led unit for display and display device having the same

专利摘要:
A light-emitting device for a display includes the first LED subunit, the second LED subunit and the third LED subunit, an insulation layer that substantially covers the first, second and third LED subunits and the electrode pads electrically connected to the first, second and third LED subunits, in which the first LED subunit is arranged in a partial region of the second LED subunit, the second LED subunit is arranged in a partial region of the third LED subunit, the layer The insulation circuit has openings for electrical connection between the electrodes, a common electrode is connected to the first, second and third LED subunits through the openings in the insulation layers, first, second and third electrode pads are connected to the first, second and third subunits LEDs, respectively, through at least one of the openings, and the first, second and third LED subunits are configured for to be triggered independently using the electrode pads.
公开号:BR112020012281A2
申请号:R112020012281-5
申请日:2018-12-19
公开日:2020-11-24
发明作者:Jong Hyeon Chae；Chang Yeon Kim；Seong Gyu Jang；Ho Joon Lee；Jong Min JANG；Dae Sung Cho
申请人:Seoul Viosys Co., Ltd.；
IPC主号:

专利说明:

[001] [001] Exemplary implementations of the invention generally refer to a stacked light-emitting structure and a display device that includes it and, more specifically, to a micro light-emitting diode for a display and a display device including the same.
[002] [002] Display devices using light-emitting diodes (LED) were recently developed. A display device using LED can generally be formed by forming LED structures individually grown in red (R), green (G) and blue (B) on a final substrate.
[003] [003] However, in addition to meeting the needs for high resolution and color in a display device, there are increasing needs for a display device with a high level of purity and color reproducibility, which can be manufactured using a method relatively simple manufacturing.
[004] [004] A light-emitting diode (LED) generally refers to an inorganic light source and has been used in a wide range of fields, such as display devices, vehicle lamps and general lighting. As an LED has advantages with longer life, lower energy consumption and is faster than an existing light source, it quickly replaced existing light sources.
[005] [005] Until now, conventional LEDs have been mainly used as a background source in display devices. However,
[006] [006] Display devices generally emit multiple colors using mixed colors of blue, green and red. Each pixel on a display device includes blue, green, and red subpixels. A color for a specific pixel is determined based on the colors of those subpixels, and an image is implemented by a combination of those pixels.
[007] [007] In a micro LED display, the micro LEDs are arranged in a two-dimensional (2D) plane to correspond to each subpixel and, therefore, may require an arrangement of a large number of micro LEDs on a single substrate. However, a micro LED generally has a small form factor, such as a surface area of around 10,000 square micrometers or less, which can cause several problems during manufacture due to its small form factor. For example, handling a micro LED is difficult due to the small form factor and therefore it is difficult to assemble the large number of micro LEDs needed for a typical display panel, which can exceed millions of micro LEDs.
[008] [008] In addition, since the subpixels are arranged in a two-dimensional plane, an area occupied by a pixel that includes blue, green and red subpixels is relatively large. As such, organizing the subpixels within a limited area may require reducing the area of each LED chip, which in turn can deteriorate the brightness of the subpixels due to the reduction in the light emitting area.
[009] [009] The information disclosed above regarding the state of the art is only for the understanding of the foundations of the inventive concepts and, therefore, may contain information that does not constitute the prior art.
[010] [010] Light emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them have a stacked light emitting structure that is simple and can be made with a simple manufacturing method. For example, the sides of the LED cells may have a predetermined slope to facilitate the formation of an optically non-transmissive film arranged on the sides of the LED cells to prevent light leakage. In addition, when each of the LED cells has a conical shape at a predetermined angle, the light-reflecting effect of the optically non-transmissive film can be maximized or substantially increased. As such, the angles between the sides of each LED stack and the surface of the substrate can be the same or different from each other.
[011] [011] Light emitting diodes and display using light emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention provide a light emitting pixel for a display that allows a plurality of pixels to simultaneously be manufactured to avoid the process of individual assembly of the plurality of pixels.
[012] [012] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention provide a light-emitting diode for a display capable of increasing the light area of each subpixel without increasing the pixel area.
[013] [013] Light emitting diodes and display using light emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention provide a light emitting device for a display capable of reducing the process time associated with mounting LEDs.
[014] [014] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention provide a light-emitting diode for a display having a high reliability and a structure stable. For example, providing LED batteries and connection layers with sloping side surfaces can reduce or prevent the likelihood of disconnecting a connector that electrically communicates with the LED cells, compared to when the LED cells and the connection layers have vertical side surfaces and therefore pixel reliability can be improved. As another example, one or more layers of hydrophilic material can be used to improve the adhesion of one or more bonding layers provided within or between the LED cells, thereby reducing or preventing the occurrence of peeling. As another example, one or more layers of shock absorption can be used in LED batteries to reduce or prevent the occurrence of defects such as detachment.
[015] [015] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs built, in accordance with the principles and some exemplary implementations of the invention, are capable of being activated in a passive way of driving the matrix and active way of matrix activation.
[016] [016] Additional characteristics of the inventive concepts will be presented in the description below and, in part, will be evident from the description or can be learned by practicing the inventive concepts.
[017] [017] A stacked light-emitting structure, according to an exemplary embodiment, includes a substrate including an upper surface and a lower surface, a plurality of sequentially stacked epitaxial subunits arranged on the substrate and configured to emit light of different length ranges. wave, each epitaxial subunit having a light-emitting region that overlaps the light-emitting region of an adjacent epitaxial subunit and a substantially non-transmissive film covering at least a portion of the lateral surfaces of the epitaxial subunits, in which the lateral surfaces of the epitaxial subunits are inclined with respect to one of the upper and lower surfaces of the substrate.
[018] [018] An angle formed between the lateral surfaces of the epitaxial subunits and the upper surface of the substrate can be from about 45 degrees to about 85 degrees.
[019] [019] Epitaxial subunits can include first, second and third epitaxial cells stacked sequentially.
[020] [020] A lateral surface of at least one of the first, second and third epitaxial cells can form an angle with one of the upper and lower surfaces of the substrate which is different from an angle formed by a lateral surface of another of the first, second and third epitaxial cells and a substrate surface.
[021] [021] The epitaxial subunits can be arranged on the upper surface of the substrate, and the light from the epitaxial subunits can be configured to be emitted in a direction away from the upper surface of the substrate.
[022] [022] Each of the epitaxial subunits can have a peripheral region around the light-emitting region and the substantially non-transmissive film can be arranged in the peripheral region.
[023] [023] The epitaxial subunits can be arranged on the upper surface of the substrate, and the light from the epitaxial subunits can be configured to be emitted in one direction towards the lower surface of the substrate.
[024] [024] The substantially non-transmissive film can overlap the epitaxial subunits in a flat view.
[025] [025] The substantially non-transmissive film may include at least one of a light reflecting film and a dielectric mirror.
[026] [026] The substantially non-transmissive film may include metal.
[027] [027] Epitaxial subunits can be configured to be triggered independently of one another.
[028] [028] The light emitted from each of the epitaxial subunits can have different energy bands and the light emitted from each of the epitaxial subunits can have energy bands in an increasing order from the lowest epitaxial subunit to the highest epitaxial subunit.
[029] [029] The light emitted by one of the epitaxial subunits can be configured to be transmitted through another epitaxial subunit arranged above.
[030] [030] At least one of the epitaxial subunits can be configured to transmit about 80% or more of the light emitted from the epitaxial subunit arranged under it.
[031] [031] Epitaxial subunits may include a first epitaxial cell configured to emit a first colored light, a second epitaxial cell arranged in the first epitaxial cell and configured to emit a second colored light with a wavelength range different from that of the first colored light and a third epitaxial cell arranged in the second epitaxial cell and configured to emit a third colored light having a wavelength range different from the first and second colored lights.
[032] [032] The first, second and third colored lights can be red light, green light and blue light, respectively.
[033] [033] The stacked light-emitting structure can include a micro-light emitting diode with a surface area of less than about 10,000 µm square.
[034] [034] The first colored light can be any of the red, green and blue lights, the second colored light can be any of the red, green and blue lights other than the first colored light and the third colored light can be any of the light red, green and blue different from the first and second colored lights.
[035] [035] At least one of the first, second and third epitaxial cells may have irregularities formed on its upper surface.
[036] [036] A display device including a plurality of pixels, at least some of which comprise the stacked light-emitting structure, according to exemplary modalities.
[037] [037] The display device can be configured to be activated in a passive matrix way and in an active matrix way.
[038] [038] A pixel of light emitting diode (LED) for a display, according to an exemplary modality, includes a first LED subunit, a second LED subunit arranged in the first LED subunit, a third LED subunit arranged in the second LED subunit, a connector arranged on at least one side surface of the first, second and third LED subunits and electrically connected to at least one of the LED subunits, and an insulation layer to isolate the connector from at least one side surface of the subunits LED, on which at least one side surface of the LED subunits is inclined with respect to a lower surface of one of the first, second and third LED subunits, and the connector is arranged on the inclined side surface of the LED subunits.
[039] [039] The first LED subunit, the second LED subunit and the LED subunit can include a first LED battery, a second LED battery and a third LED battery, respectively, and the first, second and third LED batteries. LEDs can be configured to emit red light, green light and blue light, respectively.
[040] [040] The LED pixel can include a micro light emitting diode with a surface area of less than about 10,000 µm square.
[041] [041] The first LED subunit can be configured to emit any red, green and blue light, the second LED subunit can be configured to emit a light other than red, green and blue from the first LED subunit.
[042] [042] The light generated in the first LED subunit can be configured to pass through the second and third LED subunits and be emitted to the outside of the LED pixel, the light generated in the second LED subunit can be configured to pass through the third LED subunit and emitted to the outside of the LED pixel, the second LED subunit can be arranged in a partial region of the first LED subunit and the third LED subunit can be arranged in a partial region of the second LED subunit .
[043] [043] The light generated in the first LED subunit can be configured to be emitted to the outside of the LED pixel without going through the second LED subunit, and the light generated in the second LED subunit can be configured to be emitted outward of the LED pixel without going through the third LED subunit.
[044] [044] The LED pixel can further include a substrate on which the first LED subunit is arranged, on which the substrate includes GaAs and the first LED subunit includes semiconductor layers based on AlGaInP.
[045] [045] The LED pixel can also include a distributed Bragg reflector interposed between the substrate and the first LED subunit, in which the distributed Bragg reflector includes semiconductor layers.
[046] [046] The LED pixel may also include passageways that pass through the substrate, in which the passageways include a first passage electrically connected to a second conductivity type semiconductor layer of the first LED subunit, a second electrically connected to a second conductivity type semiconductor layer of the second LED subunit and a third path electrically connected to a second conductivity type semiconductor layer of the third LED subunit and the connector is electrically connected to at least one of the first, second and third passageways.
[047] [047] The LED pixel can also include a first layer of interposition between the first and second LED subunits and a second layer of interposition between the second and third LED subunits, in which each of the first and second layers of LED The connection includes a lateral surface inclination and the connector is arranged on at least one of the inclined lateral surfaces of the first and second connection layers.
[048] [048] The LED pixel can also include a first ohmic electrode interposed between the first and the second bonding layer, the first ohmic electrode being in ohmic contact with the second LED subunit and a second ohmic electrode interposed between the second and the third connection layer, the second ohmic electrode in ohmic contact with the third LED subunit.
[049] [049] A first conductivity type semiconductor layer of the first LED subunit, a first conductivity type semiconductor layer of the second LED subunit and a first conductivity type semiconductor layer of the third LED subunit can be electrically connected to each other. another.
[050] [050] A display device may include a circuit board, and a plurality of pixels arranged on the circuit board, in which at least some of the pixels include the LED pixel, according to exemplary modalities.
[051] [051] The circuit board can include a passive or active circuit and the subunits from the first to the third LED can be electrically connected to the circuit board.
[052] [052] A light-emitting device for a display, according to an exemplary embodiment, includes a first LED subunit, a second LED subunit located below the first LED subunit, a third LED subunit located below the second subunit of LED, an insulation layer that substantially covers the first, second and third LED subunits and electrode pads electrically connected to the first, second and third LED subunits, the electrode pads including a common electrode, a first electrode pad, a second electrode pad and a third electrode pad, in which the first LED subunit is arranged in a partial region of the second LED subunit, the second LED subunit is arranged in a partial region of the third LED subunit, the insulation has openings for electrical connection between the electrodes, the common electrode pad is connected to the first, second and third LED subunits via the To the openings in the insulation layer, the first, second and third electrode pads are connected to the first, second and third LED subunits, respectively, through at least one of the openings, and the first, second and third LED subunits. are configured to be triggered independently using the electrode pads.
[053] [053] The light generated in the first LED subunit can be configured to be emitted to the outside of the light emitting device through the second LED subunit and the third LED subunit, and the light generated in the second LED subunit can be configured to be emitted to the outside of the light emitting device through the third LED subunit.
[054] [054] The first, second and third LED subunits can include the first, second and third LED batteries configured to emit red light, green light and blue light, respectively.
[055] [055] The light-emitting device may include a micro-LED with a surface area less than about
[056] [056] The first LED subunit can be configured to emit any red, green and blue light, the second LED subunit can be configured to emit a light other than red, green and blue from the first LED subunit, and the third LED subunit can be configured to emit a light other than red, green and blue from the first and second LED subunits.
[057] [057] The light emitting device may also include a first transparent electrode interposed between the first LED subunit and the second LED subunit and in ohmic contact with a lower surface of the first LED subunit, a second transparent electrode interposed between the second LED subunit and third LED subunit and in ohmic contact with the lower surface of the second LED subunit and a third transparent electrode arranged to be in ohmic contact with the upper surface of the third LED subunit, at least some of the openings in the insulation layer exposes the first, second and third transparent electrodes.
[058] [058] One of the openings in the insulation layer can expose the second transparent electrode and the third transparent electrode together.
[059] [059] The first, second and third LED subunits can each include a first conductivity type semiconductor layer and a second conductivity type semiconductor layer, the first, second and third transparent electrodes can be electrically connected to the second conductivity type semiconductor layers of the first, second and third LED subunits, respectively, and the second conductivity type semiconductor layer of the third LED subunit can be arranged in a partial region of the first conductivity type semiconductor layer of the third subunit LED.
[060] [060] The first LED subunit and the second LED subunit can be arranged in an upper region of the second conductivity type semiconductor layer of the third LED subunit.
[061] [061] The second and third electrode pads can be electrically connected to the first conductivity type semiconductor layer of the second LED subunit and the first conductivity type semiconductor layer of the third LED subunit, respectively.
[062] [062] The second and third electrode pads can be connected directly to the first conductivity type semiconductor layers of the second LED subunit and the third LED subunit, respectively.
[063] [063] The light emitting device may also include a first color filter disposed between the third transparent electrode and the second transparent electrode and a second color filter disposed between the second LED subunit and the first transparent electrode.
[064] [064] The first color filter and the second color filter can include layers of insulation with different refractive indexes from each other.
[065] [065] The light-emitting device may further include a first bonding layer interposed between the first arranged color filter and the second transparent electrode and a second bonding layer interposed between the second color filter and the first transparent electrode.
[066] [066] The light-emitting device may further include a substrate connected to a lower surface of the third LED subunit, in which the substrate includes at least one of a sapphire material and a gallium nitride material.
[067] [067] The second LED subunit and the third LED subunit can be connected in common through one of the openings in the insulation layer.
[068] [068] The light-emitting device may also include an ohmic electrode disposed between the electrode pads and the first LED subunit and in ohmic contact with the first LED subunit, where the first electrode pad is connected to the ohmic electrode and the insulation layer comprises at least one of a light reflecting layer and a light absorbing layer.
[069] [069] A display device may include a circuit board with a drive circuit to drive light emitting devices in an active matrix drive mode or passive matrix drive mode, and a plurality of light emitter devices. light connected by plug in the circuit board, in which at least some of the light emitting devices include the light emitting device, according to exemplary modalities, in which the electrode pads are electrically connected to the circuit board.
[070] [070] The light-emitting devices can include the respective substrates connected to the third LED subunit and the substrates can be separated from each other.
[071] [071] A light emitting diode (LED) cell for a display, according to an exemplary embodiment, includes a first LED subunit, including a first conductivity type semiconductor layer and a second conductivity type semiconductor layer, a second LED subunit arranged in the first LED subunit, a third LED subunit arranged in the second LED subunit, a first connection layer arranged between the first and second LED subunits, a second connection layer arranged between the second LED and the third LED subunit, and at least one buffer layer disposed between the adjacent LED subunits.
[072] [072] The buffer layer may include a first hydrophilic layer in contact with at least two of the first LED subunit, the first bonding layer, the second bonding layer and the second LED subunit.
[073] [073] The LED stack may further include a support substrate disposed below the first LED subunit, a third bonding layer disposed between the support substrate and the first LED subunit and a second hydrophilic layer disposed on a substrate surface. of support, in which the first and second hydrophilic layers may include at least one of a SiO2 layer and a modified layer on the surface.
[074] [074] The LED stack can also include an ohmic electrode in ohmic contact with the first conductivity type semiconductor layer of the first LED subunit and disposed between the first LED subunit and the supporting substrate, a reflective electrode in ohmic contact. with the second conductivity type semiconductor layer of the first LED subunit and disposed between the first LED subunit and the supporting substrate, an interconnect line disposed below the first LED subunit, isolated from the reflecting electrode and connected to the ohmic electrode, and an insulation layer that insulates the interconnect line from the reflector electrode, in which the third connection layer is in contact with the interconnect line and the insulation layer.
[075] [075] The light generated in the first LED subunit can be configured to be transmitted through the second LED subunit and the third LED subunit and emitted to the outside of the LED stack, and the light generated in the second LED subunit can be be configured to be transmitted through the third LED subunit and output to the outside of the LED subunit.
[076] [076] The first, second and third LED subunits can be configured to emit red light, green light and blue light, respectively.
[077] [077] The LED stack can include a micro-LED with a surface area of less than about 10,000 µm square.
[078] [078] The first LED subunit can be configured to emit any red, green and blue light, the second LED subunit can be configured to emit a light other than red, green and blue from the first LED subunit, and the third LED subunit can be configured to emit a light other than red, green and blue from the first and second LED subunits
[079] [079] The LED stack can also include a first color filter interposed between the first link layer and the second LED subunit and configured to transmit light generated from the first LED subunit and reflect the light generated from the second LED subunit, and a second color filter interposed between the second link layer and the third LED subunit and configured to transmit light generated in the first and second LED subunits and reflect the light generated in the third LED subunit.
[080] [080] At least one of the first color filter and the second color filter can include a SiO2 layer and at least one of the first bonding layer and the second bonding layer can be in contact with the SiO2 layer.
[081] [081] A display device may include a plurality of pixels aligned on a support substrate, in which at least some of the pixels may include the LED stack, according to exemplary modalities.
[082] [082] The second and third LED subunits can each include a first conductivity type semiconductor layer and a second conductivity type semiconductor layer, the first conductivity type semiconductor layers of the first, second and third LED subunits of each pixels are electrically connected to a common line and the second conductivity type semiconductor layers of the first, second and third LED subunits are electrically connected to different lines.
[083] [083] The common line can include a data line, and the different lines can include scan lines.
[084] [084] The buffer layer may include a shock absorber layer configured to cushion the impact between the two adjacent LED subunits.
[085] [085] At least one of the first and second connecting layers can be arranged in the shock absorbing layer.
[086] [086] The shock absorbing layer can be arranged in at least one of the first and second bonding layers.
[087] [087] At least one of the first and second bonding layers can include spin-on glass (SOG).
[088] [088] The shock-absorbing layer may include silicon oxide.
[089] [089] The buffer layer may include a first buffer layer disposed between the first and second LED subunits and a second buffer layer disposed between the second and third LED subunits.
[090] [090] A thickness of the first buffer layer may be greater than a thickness of the second buffer layer.
[091] [091] Each of the first buffer layer and the second buffer layer can include a shock absorbing layer to cushion the impact between the two adjacent LED subunits, and the shock absorbing layer of the first buffer layer can have a thickness greater than the shock absorbing layer of the second buffer layer.
[092] [092] The LED stack may further include a first wavelength pass filter disposed between the first LED subunit and the first buffer layer and a second wavelength pass filter disposed between the second LED subunit and the second layer of buffer.
[093] [093] The LED battery can also include a contact arranged in the LED subunits to apply a common voltage and a light emitting signal, in which the contact can include first and second common contacts to apply the voltage common to the first, second and third LED subunits and first, second and third contacts to apply the light emitting signal to each of the first, second and third LED subunits.
[094] [094] The LED stack can also include first, second and third signal lines to apply the light emitting signal to the first, second and third LED subunits and a common line to apply the common voltage to the first, second and third subunits LEDs, in which the first, second and third signal lines can be connected to the first, second and third contacts, respectively, and the common line can be connected to the first and second common contacts.
[095] [095] The first, second and third signal lines can extend substantially in a first direction, and the common line can extend substantially in a second direction, crossing the first direction
[096] [096] The first common contact can be arranged in the first LED subunit.
[097] [097] A display device may include a plurality of pixels, at least some that may include the stack of light-emitting diodes, according to exemplary modalities.
[098] [098] The display device can be configured to be activated in a passive matrix way and in an active matrix way.
[099] [099] The buffer layer can have a multilayer structure including a silicon nitride film and a silicon oxide film, and the silicon nitride film can contact the first LED subunit and the silicon oxide film can contact the first adhesive layer.
[0100] [0100] The LED stack can also include a Bragg reflector distributed between the silicon nitride film and the silicon oxide film.
[0101] [0101] The first, second and third LED subunits can be configured to emit red light, green light and blue light, respectively.
[0102] [0102] A display device may include a substrate including a circuit board including a thin film transistor and a plurality of pixels arranged on the substrate, at least some of the pixels may include the stack of light emitting diodes, according to with exemplary modalities.
[0103] [0103] The display apparatus may further include a plurality of metal bonding materials disposed on the first adhesive layer.
[0104] [0104] The display apparatus may also include electrode pads disposed on the substrate and first electrode pads disposed under the first LED subunit, in which each of the metal bonding materials can connect the electrode pads of the substrate and the first electrode pads.
[0105] [0105] An empty space can be formed between the first adhesive layer and the metal bonding material.
[0106] [0106] The display apparatus may further include a second adhesive layer interposed between the first LED subunit and the second LED subunit, and a third adhesive layer interposed between the second LED subunit and the third LED subunit, in which the second and third adhesive layers may include metal bonding materials.
[0107] [0107] The first, second and third LED subunits can be electrically connected to the first electrode pads, the n-type semiconductor layers of the first, second and third LED subunits can be electrically connected in common to one of the first electrode pads , p-type semiconductor layers of the first, second and third LED subunits can be electrically connected to the first electrode pads that are different from each other, respectively, the first, second and third LED subunits can be configured to be actionable independently, the light generated in the first LED subunit can be configured to be transmitted through the second and third LED subunits and emitted to the outside, and the light generated in the second LED subunit can be configured to be transmitted through the third LED subunit. and issued abroad.
[0108] [0108] The type n semiconductor layers of the first, second and third LED subunits can be grounded.
[0109] [0109] The display device may also include connectors that electrically connect the second LED subunit and the third LED subunit to the first electrodes.
[0110] [0110] Connectors can pass through at least one of the first LED subunit and the second LED subunit, and are arranged under the third LED subunit.
[0111] [0111] Connectors can include a first connector, a second connector and a third connector that pass through the first LED subunit, the first connector can be electrically connected to the type n semiconductor layer of the first LED subunit and the second and the third connectors can be electrically isolated from the first LED subunit and electrically connected to the first electrode pads, respectively.
[0112] [0112] The connectors can also include a fourth connector and a fifth connector that pass through the second LED subunit, the fourth connector can electrically connect the n-type semiconductor layer of the second LED subunit to the first connector and the fifth connector can be electrically isolated from the second LED subunit and connected to the third connector.
[0113] [0113] The display device may also include a barrier that separates the pixels from each other.
[0114] [0114] The display device may also include a first color filter interposed between the first LED subunit and the second LED subunit, and configured to transmit light generated in the first LED subunit and reflect the light generated in the second LED subunit , and a second color filter interposed between the second LED subunit and the third LED subunit, and configured to transmit light generated in the first and second LED subunits and reflect the light generated in the third LED subunit.
[0115] [0115] The upper and lower surfaces of the metal bonding materials can be substantially flat and the side surfaces of the metal bonding materials can be substantially curved.
[0116] [0116] It should be understood that both the general description above and the detailed description below are exemplary and explanatory and are intended to provide additional explanations of the invention as claimed.
[0117] [0117] Light emitting diodes built according to the principles and some exemplary implementations of the invention and displays using them have a stacked light emitting structure that is simple and can be made with a simple manufacturing method. For example, the sides of the LED cells may have a predetermined slope to facilitate the formation of an optically non-transmissive film arranged on the sides of the LED cells to prevent light leakage. In addition, when each of the LED cells has a conical shape at a predetermined angle, the light-reflecting effect of the optically non-transmissive film can be maximized or substantially increased. As such, the angles between the sides of each LED stack and the surface of the substrate can be the same or different from each other.
[0118] [0118] Light emitting diodes and display using light emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention provide a light emitting pixel for a display that allows a plurality of pixels to simultaneously be manufactured to avoid the process of individual assembly of the plurality of pixels.
[0119] [0119] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention provide a light-emitting diode for a display capable of increasing the light area of each subpixel without increasing the pixel area.
[0120] [0120] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention provide a light-emitting device for a display capable of reducing process time associated with mounting LEDs.
[0121] [0121] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs, built according to the principles and some exemplary implementations of the invention provide a light-emitting diode for a display having a high reliability and a structure stable. For example, providing LED batteries and connection layers with sloping side surfaces can reduce or prevent the likelihood of disconnecting a connector that electrically communicates with the LED cells, compared to when the LED cells and the connection layers have vertical side surfaces and therefore pixel reliability can be improved. As another example, one or more layers of hydrophilic material can be used to improve the adhesion of one or more bonding layers provided within or between the LED cells, thereby reducing or preventing the occurrence of peeling. As another example, one of the most shock absorbing layers can be used in LED batteries to reduce or prevent the occurrence of defects, such as detachment.
[0122] [0122] Light-emitting diodes and displays using light-emitting diodes, for example, micro LEDs built, in accordance with the principles and some exemplary implementations of the invention, are capable of being activated in a passive way of driving the matrix and active way of matrix activation.
[0123] [0123] The attached figures, which are included to provide a further understanding of the invention and are incorporated and form part of this specification, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the inventive concepts.
[0124] [0124] FIG. 1 is a cross-sectional view of a stacked light-emitting structure, according to an exemplary embodiment.
[0125] [0125] FIG. 2 is a cross-sectional view of a stacked light-emitting structure including a wiring part, according to an exemplary embodiment.
[0126] [0126] FIG. 3 is a cross-sectional view of a stacked light-emitting structure, according to an exemplary embodiment.
[0127] [0127] FIG. 4 is a plan view of a display device, according to an exemplary embodiment.
[0128] [0128] FIG. 5 is an enlarged plan view of a portion P1 of FIG. 4.
[0129] [0129] FIG. 6 is a structural diagram of a display device, according to an exemplary embodiment.
[0130] [0130] FIG. 7 is a one-pixel circuit diagram in a passive display device, according to an exemplary embodiment.
[0131] [0131] FIG. 8 is a one-pixel circuit diagram of an active-type display device, according to an exemplary embodiment.
[0132] [0132] FIG. 9 is a plan view of a pixel, according to an exemplary embodiment.
[0133] [0133] FIG. 10A and FIG. 10B are cross-sectional views taken along lines I-I 'and II-II' in FIG. 10, respectively.
[0134] [0134] FIG. 11, FIG. 13, FIG. 15, FIG. 17, FIG. 19, FIG. 21 are plan views illustrating a method of manufacturing a pixel on a substrate, according to an exemplary embodiment.
[0135] [0135] FIG. 12A and FIG. 12B are cross-sectional views taken along line I-I 'and line II-II' and in FIG. 11, respectively.
[0136] [0136] FIG. 14A and FIG. 14B are cross-sectional views taken along line I-I 'and line II-II' and of FIG. 13, respectively.
[0137] [0137] FIG. 16A and FIG. 16B are cross-sectional views taken along line I-I 'and line II-II' and of FIG. 15, respectively.
[0138] [0138] FIG. 18A and FIG. 18B are cross-sectional views taken along line I-I 'and line II-II' and of FIG. 17, respectively.
[0139] [0139] FIG. 20A and FIG. 20B are cross-sectional views taken along line I-I 'and line II-II' and of FIG. 19, respectively.
[0140] [0140] FIG. 22A and FIG. 22B are cross-sectional views taken along line I-I 'and line II-II' and of FIG. 21, respectively.
[0141] [0141] FIG. 23 is a cross-sectional view of a stacked light-emitting structure, according to an exemplary embodiment.
[0142] [0142] FIG. 24 is a cross-sectional view illustrating a stacked light-emitting structure including a wiring piece, according to an exemplary embodiment.
[0143] [0143] FIG. 25 is a plan view of a stacked light-emitting structure, according to an exemplary embodiment.
[0144] [0144] FIG. 26 is a cross-sectional view taken along line III-III 'of FIG. 25.
[0145] [0145] FIG. 27, FIG. 29, FIG. 31, and FIG. 33 are plan views illustrating a method of making an epitaxial cell, according to an exemplary embodiment.
[0146] [0146] FIG. 28 is a cross-sectional view taken along line III-III of FIG. 27.
[0147] [0147] FIG. 30A and FIG. 30B are seen in cross section taken along line III-III 'of FIG. 29, respectively, according to exemplary modalities.
[0148] [0148] FIG. 32A and FIG. 32B are seen in cross section taken along line III-III 'of FIG. 31, respectively, according to exemplary modalities.
[0149] [0149] FIG. 34 is a cross-sectional view taken along line III-III of FIG. 33.
[0150] [0150] FIG. 35 is a schematic plan view illustrating a display apparatus, according to an exemplary embodiment.
[0151] [0151] FIG. 36 is a schematic cross-sectional view of a pixel-emitting diode (LED) light for a display according to an exemplary embodiment.
[0152] [0152] FIG. 37A and FIG. 37B are circuit diagrams of a display device, according to an exemplary embodiment.
[0153] [0153] FIG. 38A and FIG. 38B are an enlarged plan view and an enlarged bottom view of a pixel of a display device, according to exemplary embodiments, respectively.
[0154] [0154] FIG. 39A is a schematic cross-sectional view taken along a line A-A of FIG. 38A.
[0155] [0155] FIG. 39B is a schematic cross-sectional view taken along a line B-B of FIG. 38A.
[0156] [0156] FIG. 39C is a schematic cross-sectional view taken along a line C-C of FIG. 38A.
[0157] [0157] FIG. 39D is a schematic cross-sectional view taken along a D-D line of FIG. 38A.
[0158] [0158] FIG. 40A, FIG. 41A, FIG. 42A, FIG. 43A, FIG. 44A, FIG. 45A, FIG. 46A, and FIG. 47B are schematic plan views illustrating a method of manufacturing a display apparatus, according to an exemplary embodiment.
[0159] [0159] FIG. 40B, FIG. 41B, FIG. 42B, FIG. 43B, FIG. 44B, FIG. 45B, FIG. 46B and FIG. 47B are seen in cross section taken along line E-E of FIG. 40A, FIG. 41A, FIG. 42A, FIG. 43A, FIG. 44A, FIG. 45A, FIG. 46A, and FIG. 47B, respectively.
[0160] [0160] FIG. 48 is a schematic cross-sectional view of an LED pixel for a display, according to another exemplary embodiment.
[0161] [0161] FIG. 49 is an enlarged one-pixel plan view of a display device, according to an exemplary embodiment.
[0162] [0162] FIG. 50A and FIG. 50B are seen in cross section taken along the lines G-G and H-H of FIG. 49, respectively.
[0163] [0163] FIG. 51 is a schematic plan view of a display apparatus according to an exemplary embodiment.
[0164] [0164] FIG. 52A is a schematic plan view of a light emitting device according to an exemplary embodiment.
[0165] [0165] FIG. 52B and FIG. 52C are schematic cross-sectional views taken along line A-A and line B-B 'of FIG. 52A, respectively.
[0166] [0166] FIG. 53, FIG. 54, FIG. 55, FIG. 56, FIG. 57A, FIG. 57B, FIG. 58A, FIG. 58B, FIG. 59A, FIG. 59B, FIG. 60A, FIG. 60B, FIG. 61A, FIG. 61B, FIG. 62A, FIG. 62B, FIG. 63A, FIG.
[0167] [0167] FIG. 65 is a schematic cross-sectional view of a stack of light emitting diode (LED) lights for a display according to an exemplary embodiment.
[0168] [0168] FIG. 66A, FIG. 66B, FIG. 66C, FIG. 66D, FIG. 66E, and FIG. 66F are schematic cross-sectional views that illustrate a method of manufacturing a stack of light-emitting diodes for a display, according to an exemplary embodiment.
[0169] [0169] FIG. 67 is a schematic circuit diagram of a display apparatus according to an exemplary embodiment.
[0170] [0170] FIG. 68 is a schematic plan view of a display apparatus according to an exemplary embodiment.
[0171] [0171] FIG. 69 is an enlarged one-pixel plan view of the display apparatus of FIG. 68.
[0172] [0172] FIG. 70 and FIG. 71 are schematic cross-sectional views taken along line A-A and line B-B of FIG. 69, respectively.
[0173] [0173] FIG. 72A, FIG. 72B, FIG. 72C, FIG. 72D, FIG. 72E, FIG. 72F, FIG. 72G, and FIG. 72H are schematic plan views that illustrate a method of manufacturing a display device, according to an exemplary embodiment.
[0174] [0174] FIG. 73 is a cross-sectional view of a stacked light-emitting structure, according to an exemplary embodiment.
[0175] [0175] FIG. 74A and FIG. 74B are seen in cross section of a stacked light-emitting structure, according to exemplary modalities.
[0176] [0176] FIG. 75 is a cross-sectional view of a stacked light-emitting structure including a wiring part, according to an exemplary embodiment.
[0177] [0177] FIG. 76 is a cross-sectional view of a stacked light-emitting structure, according to an exemplary embodiment.
[0178] [0178] FIG. 77 is a plan view showing a display device, according to an exemplary embodiment.
[0179] [0179] FIG. 78 is an enlarged plan view showing a portion P1 of FIG. 77.
[0180] [0180] FIG. 79 is a structural diagram of a display device, according to an exemplary embodiment.
[0181] [0181] FIG. 80 is a one-pixel circuit diagram in a passive display device, according to an exemplary embodiment.
[0182] [0182] FIG. 81 is a schematic one-pixel circuit diagram of an active-type display device, according to an exemplary embodiment.
[0183] [0183] FIG. 82 is a one-pixel plan view, according to an exemplary embodiment.
[0184] [0184] FIG. 83A and FIG. 83B are cross-sectional views taken along lines I-I 'and II-II' of FIG. 82, respectively.
[0185] [0185] FIG. 84A, FIG. 84B and FIG. 84C are cross-sectional views taken along line I-I 'of FIG. 82 according to an exemplary embodiment.
[0186] [0186] FIG. 85, FIG. 87, FIG. 89, FIG. 91, FIG, 93, FIG. 95, and FIG. 97 are plan views showing a method of manufacturing a pixel on a substrate, according to an exemplary embodiment.
[0187] [0187] FIG. 86A and FIG. 86B are cross-sectional views taken along line I-I 'and line II-II' and of FIG. 85, respectively.
[0188] [0188] FIG. 88A and FIG. 88B are cross-sectional views taken along line I-I 'and line II-II' and in FIG. 87, respectively.
[0189] [0189] FIG. 90A and FIG. 90B are seen in cross section taken along line I-I 'and line II-II' and in FIG. 89, respectively.
[0190] [0190] FIG. 92A and FIG. 92B are cross-sectional views taken along line I-I 'and line II-II' and of FIG. 91, respectively.
[0191] [0191] FIG. 94A and FIG. 94B are seen in cross section taken along line I-I 'and line II-II' and in FIG. 93, respectively.
[0192] [0192] FIG. 96A and FIG. 96D are cross-sectional views taken along line I-I 'and line II-II' of FIG. 95, respectively.
[0193] [0193] FIG. 98A and FIG. 98B are cross-sectional views taken along line I-I 'and line II-II' and of FIG. 97, respectively.
[0194] [0194] FIG. 99 is a schematic plan view of a display apparatus according to an exemplary embodiment.
[0195] [0195] FIG. 100A is a partial cross-sectional view of the display apparatus of FIG. 1.
[0196] [0196] FIG. 100B is a schematic circuit diagram of a display device according to an exemplary embodiment.
[0197] [0197] FIG. 101A, FIG. 101B, FIG. 101C, FIG. 101D, FIG. 101E, FIG. 102A, FIG. 102B, FIG. 102C, FIG. 102D, FIG. 102E, FIG. 103A, FIG. 103B, FIG. 103C, FIG. 103D, FIG. 104A, FIG. 104B, FIG. 104C, FIG. 104D, FIG. 105A, FIG. 105B, FIG. 105C, FIG. 105D, FIG. 106A, FIG. 106B and FIG. 107 are schematic plan views and cross-sectional views that illustrate a method of manufacturing the display apparatus, according to an exemplary embodiment.
[0198] [0198] FIG. 108A, FIG. 108B and FIG. 108C are schematic views in partial cross section of a metal bonding material, according to exemplary modalities.
[0199] [0199] In the following description, for the purpose of explanation, several specific details are presented in order to provide a complete understanding of various exemplary embodiments or implementations of the invention. As used here, "modalities" and "implementations" are interchangeable words that are non-limiting examples of devices or methods that employ one or more of the inventive concepts disclosed herein. It is apparent, however, that several exemplary modalities can be practiced without these specific details or with one or more equivalent arrangements. In other cases, known structures and devices are shown in the form of a block diagram to avoid unnecessarily obscuring several exemplary modalities. In addition, several exemplary modalities may be different, but need not be exclusive. For example, forms, configurations and specific characteristics of an exemplary modality can be used or implemented in another exemplary modality without departing from inventive concepts.
[0200] [0200] Unless otherwise specified, the exemplary modalities illustrated should be understood as providing exemplary characteristics of varying details in some ways in which inventive concepts can be implemented in practice. Therefore, unless otherwise specified, resources, components, modules, layers, films, panels, regions and / or aspects, etc. (hereinafter, individually or collectively referred to as "elements"), the various modalities can be combined in another way, separated, exchanged and / or reorganized without departing from the inventive concepts.
[0201] [0201] The use of cross hatching and / or shading in the accompanying figures is generally provided to clarify the boundaries between adjacent elements. As such, neither the presence nor the absence of hatching or shading transmit or indicate any preference or requirement for materials, properties, dimensions, proportions, similarities between illustrated elements and / or any other characteristic, attribute, property, etc., of the elements , unless specified. In addition, in the accompanying figures, the size and relative size of the elements may be exaggerated for reasons of clarity and / or description. When an exemplary modality can be implemented differently, a specific process order can be carried out differently from the order described. For example, two processes described consecutively can be performed at substantially the same time or performed in an order opposite to the order described. In addition, similar reference numbers indicate similar elements.
[0202] [0202] When an element such as one or layer is referred to as "above", "connected to" or "attached to" or another element or layer, it can be directly on, connected to or attached to another element or layer or elements or intervening layers may be present. When, however, an element or layer is referred to as "directly in", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present. Finally, the term “connected” can refer to physical, electrical and / or fluid connections, with or without intervening elements, and the D1 axis, the D2 axis and the D3 axis are not limited to three axes of a rectangular coordinates, such as x, y, and z axes, and can be interpreted in a broader sense, for example, the D1 axis, the D2 axis, and the D3 axis can be perpendicular to each other or can represent different directions that are not perpendicular to each other other for the purposes of ta disclosure, "at least one of X, Y and Z" and "at least one selected from the group consisting of X, Y and Z" can be interpreted as only X, only Y, only Z, or any combination of two or more than X, Y and Z, such as XYZ, XYY, YZ and ZZ. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.
[0203] [0203] Although the terms "first", "second" etc. can be used here to describe various types of elements, these elements should not be limited by those terms. These terms are used to distinguish one element from another element. Thus, a first element discussed below could be called a second element without departing from the teachings of disclosure.
[0204] [0204] Spatially relative terms, such as "below", "below", "under", "lower", "above", "upper", "above", "above", "highest", "lateral" ( for example, as in the "side wall"), and the like, can be used here for descriptive purposes and thus to describe an element related to other elements, as illustrated in the figures. Spatially relative terms are intended to cover different orientations of a device in use, operation and / or manufacture, in addition to the orientation shown in the figures. For example, if the device in the figures is turned over, the elements described as "below" or "under" other elements or characteristics will be oriented "above" the other elements or characteristics. Thus, the exemplary term "below" can encompass an orientation above and below. In addition, the apparatus may be otherwise oriented (for example, rotated 90 degrees or in other orientations) and, as such, the spatially relative descriptors used herein interpreted accordingly.
[0205] [0205] The terminology used in this document is intended to describe particular modalities and is not intended to be limiting. As used in this document, the singular forms "one", "one" and "o / a" are also intended to include plural forms, unless the context clearly indicates otherwise. In addition, the terms "comprises", "comprising", "includes" and / or "including", when used in this specification, specify the presence of declared resources, integers, steps, operations, elements, components and / or groups, but it does not exclude the presence or addition of one or more resources, integers, steps, operations, elements, components and / or groups thereof. Note also that, as used in this document, the terms
[0206] [0206] Various exemplary modalities are described here with reference to sectional and / or exploded illustrations which are schematic illustrations of idealized exemplary modalities and / or intermediate structures. As such, variations in the shapes of the illustrations are expected as a result, for example, of manufacturing techniques and / or tolerances. Thus, exemplary modalities disclosed in this document should not necessarily be interpreted as limited to the particular illustrated shapes of the regions, but should include deviations in the shapes that result, for example, from manufacturing. In this way, the regions illustrated in the figures may be schematic in nature and the shapes of those regions may not reflect the actual shapes of the regions of a device and, as such, are not necessarily intended to be limiting.
[0207] [0207] Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meanings as those commonly understood by a specialist in the subject to which this disclosure is a part. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant technique and should not be interpreted in an ideal or excessively formal manner unless expressly defined here.
[0208] [0208] In the following, examples of modalities will be described in detail with respect to the attached figures. As used herein, a light-emitting device or a light-emitting diode according to exemplary modalities may include a micro LED, which has a surface area of less than about 10,000 µm square, as known in the art. In other exemplary embodiments, micro LEDs can have a surface area of less than about 4,000 µm square, or less than about
[0209] [0209] FIG. 1 is a cross-sectional view of a stacked light-emitting structure, according to an exemplary embodiment.
[0210] [0210] Referring to FIG. 1, a light-emitting stacked structure, according to an exemplary embodiment, includes a plurality of sequentially stacked epitaxial cells and optically non-transmissive films covering the sides of the epitaxial cells. The plurality of epitaxial cells are provided on substrate 10. Substrate 10 can have substantially a plate shape including an upper surface and a lower surface. As used in this document, a stacked light-emitting structure, according to exemplary modalities, can include a micro-light emitting structure or a micro LED, which generally has a form factor of about 200 square micrometers or less, or about 100 square micrometers or less in the surface area, as is known in the art.
[0211] [0211] A plurality of epitaxial cells can be mounted on the top surface of substrate 10, and substrate 10 can be provided in a variety of ways. The substrate 10 can be formed of an insulating material. Examples of the substrate material 10 can include glass, quartz, silicon, organic polymer, organic-inorganic composite or the like. However, the inventive concepts are not limited to a particular material of the substrate 10, as long as it has an insulating property. In an exemplary embodiment, substrate 10 may further include a spinning piece that can provide a light-emitting signal and a common voltage for the respective epitaxial cells. In particular, when each of the epitaxial cells is activated in a type of active matrix, a drive element including a thin film transistor can be further arranged on the substrate 10, in addition to the spinning piece. For this purpose, substrate 10 can be supplied as a printed circuit board 10 or as a composite substrate 10 having a spinning piece and / or a driving element formed of glass, silicon, quartz, organic polymer or organic / inorganic composite. .
[0212] [0212] Epitaxial cells are stacked sequentially on the top surface of substrate 10 and can emit light respectively. In an exemplary embodiment, two or more epitaxial cells can be provided to emit light of different wavelength bands from each other, respectively. More particularly, a plurality of epitaxial cells can be provided, having different energy bands, respectively, from each other. The epitaxial stack on substrate 10 can be arranged sequentially on top of one another. According to an exemplary embodiment, the epitaxial cell can include first, second and third epitaxial cells 20, 30 and 40 arranged sequentially on the substrate 10.
[0213] [0213] Each of the epitaxial cells can emit light towards the front of the substrate 10. The light emitted by one epitaxial cell can pass through another epitaxial cell located in the light path and travels in the frontal direction. For example, the front direction can correspond to a direction along which the first to third epitaxial cells 20, 30 and 40 are stacked, as shown in FIG. 1.
[0214] [0214] Each of the epitaxial cells can emit colored light from a visible light strip of several wavelength bands. For example, the light emitted from the lowest epitaxial cell can be colored light with the longest wavelength (for example, the lowest energy range), and the wavelength of the light emitted by the epitaxial cells can be make it shorter along a direction away from the substrate 10. The light emitted from the tallest epitaxial cell may have colored light with the shortest wavelength (for example, the highest energy range). For example, the first epitaxial cell 20 can emit the first colored light L1, the second epitaxial cell 30 can emit the second colored light L2 and the third epitaxial cell 40 can emit the third colored light L3. The first to third colored lights L1, L2 and L3 can correspond to a different colored light from each other, and the first to the third colored lights L1, L2 and L3 can be colored lights of different wavelength ranges from one another that decrease sequentially wavelengths. In particular, the first to third colored lights L1, L2 and L3 may have different wavelength ranges from one another and the colored light may be a shorter wavelength range (for example, higher energy) in order from the first colored light L1 to the third colored light L3. However, the inventive concepts are not limited to these, and the wavelength of the light emitted by each epitaxial cell can be modified in several ways.
[0215] [0215] In an exemplary embodiment, the first colored light L1 can be red light, the second colored light L2 can be green light and the third colored light L3 can be blue light.
[0216] [0216] Henceforth, in addition to the front and rear directions mentioned above, the "front" direction of substrate 10 will be called "top" direction and the "rear" direction of substrate 10 will be called "bottom" direction. The terms "upper" or "lower" refer to relative directions, which may vary according to the location and direction of the stacked light-emitting structure.
[0217] [0217] Each of the epitaxial cells emits light in the upper direction, and each of the epitaxial cells transmits most of the light emitted by the underlying epitaxial cells. In particular, the light emitted from the first epitaxial cell 20 passes through the second epitaxial cell 30 and the third epitaxial cell 40, and travels in the frontal direction. The light emitted from the second epitaxial cell 30 passes through the third epitaxial cell 40 and travels in the frontal direction. To this end, at least some, or desirably, all epitaxial cells other than the lower epitaxial cell 20 may be composed of an optically transmissive material. As used here, the material being "optically transmissive" can refer to the transmission of all light or the transmission of at least a portion of light with a predetermined wavelength. In an exemplary embodiment, each epitaxial cell can transmit about 60% or more of the light emitted from the epitaxial cell disposed in it, or about 80% or more, in another exemplary mode, or about 90% or more in yet another exemplary modality.
[0218] [0218] An optically non-transmissive film (substantially, total reflector) 80 can be provided on the sides of the epitaxial cells, more particularly, on the sides of the first to third epitaxial cells 20, 30 and 40. The optically non-transmissive film 80 can substantially cover the entire sides of the first to third epitaxial cells 20, 30 and 40 to prevent light from being emitted from it.
[0219] [0219] Optically non-transmissive film 80 is not particularly limited as long as it blocks the transmission of light by absorbing or reflecting light. In an exemplary embodiment, the optically non-transmissive film 80 may be a distributed Bragg reflector (DBR), a metal reflective film formed in an insulation film or an organic polymer film with a black color. When a metal reflective film is used as an optically non-transmissive film, the metal reflective film may be in a floating state that is electrically isolated from components within other pixels. The reflective metal film can also be supplied as an extension of one of the components within other pixels, for example, as an extension of one of the other lines; in this case, the metal reflective film is supplied within a range that is not electrically connected to the other conductive components.
[0220] [0220] In an exemplary embodiment, the optically non-transmissive film 80 may have a simple or multilayer film structure and may include two or more different types of materials when supplied as a multilayer film. In an exemplary embodiment, the optically non-transmissive film 80 can be formed by depositing two or more insulation films of different refractive indices from one another. For example, the optically non-transmissive film 80 can be formed by stacking a material with a low refractive index and a material with a high refractive index in sequence, or alternatively stacking insulation films with different refractive indexes from one another. Materials with different refractive indexes can include SiO2 or SiNx, but the inventive concepts are not limited to these. The wavelength of the light absorbed or reflected by the optically non-transmissive film 80 can be controlled by changing its materials, the thickness of the stack, the frequency of the stack or the like.
[0221] [0221] In an exemplary embodiment, the optically non-transmissive film 80 can be provided on the sides of the pixels to prevent the phenomenon in which the light emitted by a given pixel affects adjacent pixels or the phenomenon in which the color is mixed with the light emitted by the adjacent pixels. Therefore, each of the epitaxial cells has a side in a conical shape to facilitate deposition of the optically non-transmissive film 80. In particular, the side of each of the epitaxial cells may have an inclined shape in relation to a surface of the substrate 10 (for example, an upper surface or lower surface of the substrate).
[0222] [0222] In an exemplary embodiment, the side of each of the epitaxial cells has an inclined shape in relation to a surface of the substrate 10. According to an exemplary embodiment, an angle between the sides of the first to the third epitaxial cells 20, 30 and 40 and the surface of the substrate 10 can be greater than about 0 degrees and less than about 90 degrees in a cross-sectional view. For example, when the angles between the sides of the first to third epitaxial cells 20, 30 and 40 and the substrate surface 10 is the first to the third angles θ1, θ2 and θ3, the first to the third angles θ1, θ2, and θ3 can have values in a range of about 45 degrees to about 85 degrees, respectively.
[0223] [0223] When the sides of the first to third epitaxial cells 20, 30 and 40 have a predetermined slope as described above, it can be relatively easy to form the optically non-transmissive film 80. Furthermore, when each of the epitaxial cells has a tapered shape at a predetermined angle, the effect of light reflection by the optically non-transmissive film 80 can be maximized or substantially increased. The optically non-transmissive film 80 can be formed using physical and / or chemical vapor deposition, but when the sides of the first to third epitaxial cells 20, 30 and 40 are perpendicular or almost perpendicular to the surface of the substrate 10, it can be difficult to cover sufficiently the sides of the first to third epitaxial cells 20, 30 and 40 with the optically non-transmissive film
[0224] [0224] According to an exemplary modality, when the side of each of the first to third epitaxial cells 20,
[0225] [0225] In an exemplary embodiment, the optically non-transmissive film 80 can be supplied only on the sides of the epitaxial cells, but the inventive concepts are not limited to these. For example, the optically non-transmissive film 80 may extend over a portion of the upper surface of the upper epitaxial cell to cover at least a portion of the upper surface of the upper epitaxial cell where light emission is not desired. More particularly, as shown in FIG. 1, the optically non-transmissive film 80 has a window to expose the upper surface of the epitaxial cell at the top corresponding to a region where light emission is desired. As used in this document, a light-emitting region that is visible to the user can be referred to as a "light-emitting region (EA)", and the remaining light-emitting region can be referred to as a "peripheral region". The optically non-transmissive film 80 has a window in the light-emitting region and can cover a portion of the upper surface of the third epitaxial cell 40 and all sides in the peripheral region, except for the light-emitting region. Therefore, the optically non-transmissive film 80 can cover a portion of an edge of the upper surface of the epitaxial cell to reduce the directivity angle of the emitted light, and thus interference with the light from the stacked adjacent light-emitting structures can be minimized .
[0226] [0226] In the stacked light-emitting structure, according to an exemplary modality, the signal lines for applying emitting signals to the respective epitaxial cells can be connected independently. Therefore, the respective epitaxial cells can be activated independently, and the stacked light-emitting structure can implement several colors, according to the light emission of each of the epitaxial cells. In addition, epitaxial cells that can emit light of different wavelengths are superimposed vertically on each other and therefore can be formed in a narrow area. In addition, since the sides of the epitaxial cells are slanted, it is possible to easily form the non-transmissive film 80 with sufficient thickness, and the non-transmissive film 80 can prevent the phenomenon in which the light emitted by a given pixel affects the pixels adjacent or the phenomenon in which the color is mixed with the light emitted by the adjacent pixels.
[0227] [0227] FIG. 2 is a cross-sectional view of a stacked light-emitting structure including a wiring part, according to an exemplary embodiment. In FIG. 2, the inclined shapes of each of the epitaxial cells and the insulation films shown in FIG. 1 are omitted.
[0228] [0228] Referring to FIG. 2, in a stacked light-emitting structure, according to an exemplary embodiment, each of the first to third epitaxial cells 20, 30 and 40 can be provided on substrate 10, through the first to third adhesive layers 61, 63 and 65 interposed between these. The first adhesive layer 61 may include a conductive or non-conductive material. The first adhesive layer 61 may have conductivity in some regions when it needs to be electrically connected to the substrate 10 provided below. The first adhesive layer 61 can also include a transparent or opaque material. In an exemplary embodiment, when substrate 10 is provided with an opaque material and has a spinning piece or the like formed therein, the first adhesive layer 61 may include an opaque material, for example, a light-absorbing material. For the light-absorbing material that forms the first adhesive layer 61, various polymeric adhesives can be used, including, for example, an epoxy-based polymeric adhesive.
[0229] [0229] The second and third adhesive layers 63 and 65 can include a non-conductive material and can also include an optically transmissive material. For example, an optically clear adhesive can be used for the second and third adhesive layers 65. The material to form the second and third adhesive layers 63 and 65 is not particularly limited, as long as it is optically transparent and is able to fix in a stable manner each of the epitaxial cells. For example, the second and third adhesive layers 63 and 65 can be formed from an organic material, including an epoxy-based polymer, such as SU-8, various strengths, parylene, poly (methyl methacrylate) (PMMA), benzocyclocyclobene ( BCB), spin-on glass (SOG), or others, and inorganic material, such as silicon oxide, aluminum oxide or similar. According to an exemplary embodiment, a conductive oxide can also be used as an adhesive layer, in which case the conductive oxide can be isolated from other components. When an organic material is used as an adhesive layer, the organic material can be applied to the adhesive surface and then glued at a high temperature and high pressure in a vacuum state. When an inorganic material is used as an adhesive layer, the inorganic material can be deposited on the adhesive surface and then planarized by chemical-mechanical planarization (CMP) or similar, after which the surface is subjected to plasma treatment and then bonded under high vacuum.
[0230] [0230] Each of the first to third epitaxial cells 20, 30 and 40 includes semiconductor layers of type p 25, 35 and 45,
[0231] [0231] According to an exemplary embodiment, the semiconductor layer type p 25, the active layer 23 and the semiconductor layer type 21 of the first epitaxial cell 20 may include a semiconductor material that emits red light. However, the inventive concepts are not limited to a specific color of light emitted from the first epitaxial cell
[0232] [0232] Examples of a semiconductor material that emits red light may include aluminum and gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), aluminum and indium and gallium phosphide (AlGaInP), gallium phosphide (GaP) or others. However, the semiconductor material that emits red light is not limited to this and several other materials can be used.
[0233] [0233] A first p 25p contact electrode can be provided under the p 25 semiconductor layer of the first epitaxial cell 20. The first p 25p contact electrode of the first epitaxial cell 20 can be a single layer or a multilayer metal. For example, the first p 25p contact electrode can include various materials, including metals, such as Al, Ti, Cr, Ni, Au, Ag, Ti, Sn, Ni, Cr, W, Cu or others or the alloys of themselves. The first contact electrode of type p 25p can include metal with high reflectivity and, therefore, since the first contact electrode of type p 25p is formed by a metal with high reflectivity, it is possible to increase the emission efficiency of the emitted light by the first epitaxial cell 20 in the upper direction.
[0234] [0234] The second epitaxial cell 30 includes a semiconductor layer of type p 35, an active layer 33 and a semiconductor layer of type n 31, which are arranged sequentially. The semiconductor layer type p 35, the active layer 33 and the semiconductor layer type n 31 can include a semiconductor material that emits green light. However, the inventive concepts are not limited to a specific color of light emitted from the second epitaxial cell 30.
[0235] [0235] Examples of materials for emitting green light include gallium nitride (AlGaInP) and aluminum and gallium phosphide (GaP), aluminum and indium and gallium phosphide (AlGaInP), and aluminum and gallium phosphide (AlGaP). However, the green light semiconductor material is not limited to this and several other materials can be used.
[0236] [0236] A second p 35p contact electrode is provided under the p 35 semiconductor layer of the second epitaxial cell 30. The second p 35p contact electrode is provided between the first epitaxial cell 20 and the second epitaxial cell 30, or specifically, between the second adhesive layer 63 and the second epitaxial cell 30.
[0237] [0237] The third epitaxial cell 40 includes a semiconductor layer of type p 45, an active layer 43 and a semiconductor layer of type n 41, which are arranged sequentially. The semiconductor layer type p 45, the active layer 43 and the semiconductor layer type n 41 can include a semiconductor material that emits blue light. However, the inventive concepts are not limited to a specific color of light emitted from the third epitaxial cell 40.
[0238] [0238] Examples of materials that emit blue light may include gallium nitride (GaN), indium and gallium nitride (InGaN), zinc selenide (ZnSe) or others. However, the semiconductor material that emits blue light is not limited to this and several other materials can be used.
[0239] [0239] A third p 45p contact electrode is provided under the p 45 semiconductor layer of the third epitaxial cell 40. The third p 45p contact electrode is provided between the second epitaxial cell 30 and the third epitaxial cell 40, or specifically, between the third adhesive layer 65 and the third epitaxial cell 40.
[0240] [0240] In FIG. 2, although semiconductor layers of type n 21, 31 and 41 and semiconductor layers of type p 25, 35 and 45 of the first to third epitaxial cells 20, 30 and 40 are shown as a single layer, the inventive concepts are not limit to these, and these layers can be multilayered and can also include superstructure layers. In addition, the active layers of the first to third epitaxial cells 20, 30 and 40 can include a single quantum well structure or a multi-quantum well structure.
[0241] [0241] In an exemplary embodiment, the second and third contact electrodes of the type p 35p and 45p can substantially cover the second and third epitaxial cells 30 and
[0242] [0242] In an exemplary mode, common lines can be connected to the first to the third contact electrodes of the type p 25p, 35p and 45p. The common line can be a line to which the common voltage is applied. In addition, the light emitting signal lines can be connected to the type 21 semiconductor layers 21, 31 and 41 of the first to third epitaxial cells 20, 30 and 40, respectively. For example, a common voltage SC can be applied to the first contact electrode of type p 25p, the second contact electrode of type p 35p and the third contact electrode of type p 45p through the common line, and the emission signal of light is applied to type n semiconductor layers 21, 31 and 41 from the first to the third epitaxial cells 20, 30 and 40, thus controlling the light emission from the first to the third epitaxial cells 20, 30 and 40. The light emitting signal can include the first to the third light emitting signal SR, SG and SB, corresponding to the first to the third epitaxial cells 20, 30 and 40, respectively. In an exemplary embodiment, the first light emitting signal SR can be a signal corresponding to red light, the second light emitting signal SG can be a signal corresponding to green light and the third light emitting signal SB can be a signal corresponding to a blue light emission.
[0243] [0243] According to the exemplary modality, the first to third epitaxial cells 20, 30 and 40 can be activated, according to a light emitting signal applied to each of the epitaxial cells. In particular, the first epitaxial cell 20 is activated, according to a first light emitting signal SR, the second epitaxial cell 30 is activated, according to a second light emitting signal SG and the third epitaxial cell 40 is activated, according to the third SB light emitting signal. In particular, the first, second and third trigger signals SR, SG and SB can be applied independently to the first to third epitaxial cells 20, 30 and 40, so that each of the first to third epitaxial cells 20, 30 and 40 can be conducted independently. The stacked light-emitting structure can finally provide light of various colors by combining the first to third colored lights emitted on top of the first to third epitaxial cells 20, 30 and 40.
[0244] [0244] In FIG. 2, a common voltage is described as being applied to the type 25, 35 and 45 type semiconductor layers from the first to the third epitaxial cells 20, 30 and 40, and the light emitting signal is described as being applied to the type 21 semiconductor layers , 31 and 41 of the first to third epitaxial cells 20, 30 and 40; however, inventive concepts are not limited to these. In another exemplary embodiment, a common voltage can be applied to layers 21, 31 and 41 of type n semiconductors from the first to the third epitaxial cells 20, 30 and 40, and light emitting signals can be applied to the type 25 semiconductor layers, 35 and 45 from the first to the third epitaxial cells 20, 30 and 40.
[0245] [0245] In this way, the stacked light-emitting structure of FIG. 2 can implement a color so that portions of different colored light are provided in the overlapping region, instead of implementing different colored light on different planes, away from each other. Therefore, the stacked light-emitting structure can advantageously have compactness and integration of the light-emitting element. In general, conventional light-emitting elements that emit different colors, such as red, green and blue light, are moved away from each other in a plane to obtain full colors. As such, each of the conventional light-emitting elements is generally arranged in a plane, occupying a larger area. However, according to exemplary modalities, it is possible to obtain a full color in a noticeably smaller area by providing a stacked structure with the parts of the light-emitting elements that emit different colored light superimposed in one region. Consequently, it is possible to manufacture a high resolution device even in a small area.
[0246] [0246] In addition, the conventional light-emitting device can have a complex structure and its manufacture is not easy either, because the conventional light-emitting device, including the conventional stacked light-emitting device, is manufactured by preparing the respective emitting elements separately of light and then forming separate contacts, as connecting by interconnecting lines, or others, for each of the light-emitting elements. However, according to an exemplary embodiment, the stacked light-emitting structure is formed by stacking several layers of epitaxial cells sequentially on a single substrate 10 and forming contacts in the multi-layered epitaxial cells and connecting by lines through a minimal process. In addition, compared to the conventional method of manufacturing display devices in which individual colored light-emitting elements are manufactured and assembled separately, according to exemplary embodiments, only a single stacked light-emitting structure is assembled instead of a plurality light-emitting elements, which significantly simplifies its manufacturing method.
[0247] [0247] The stacked light-emitting structure, according to an exemplary embodiment, can additionally employ several components to provide high purity and high-efficiency colored light. For example, a stacked light-emitting structure, according to an exemplary embodiment, can also include a wavelength pass filter to block the shorter wavelength light from proceeding towards the epitaxial cell that emits light of wavelength. relatively bigger wave.
[0248] [0248] In the following exemplary modalities, the differences in the exemplary modalities described above will be mainly described, in order to avoid redundancy.
[0249] [0249] FIG. 3 is a cross-sectional view of a stacked light-emitting structure including a filter of passage of predetermined wavelength according to an exemplary embodiment. In FIG. 3, some components shown in FIGS. 1 and 2 are omitted.
[0250] [0250] Referring to FIG. 3, a stacked light-emitting structure, according to an exemplary embodiment, includes a first wavelength pass filter 71 disposed between the first epitaxial cell 20 and the second epitaxial cell
[0251] [0251] The first can selectively transmit a certain wavelength light. In particular, the first wavelength pass filter 71 can transmit a first colored light emitted from the first epitaxial cell 20 while blocking or reflecting light other than the first colored light. Therefore, the first colored light emitted from the first epitaxial cell 20 can travel in the upper direction, while the second and third colored lights emitted from the second and third epitaxial cells 30 and 40 are prevented from traveling towards the first cell epitaxial 20 and reflected or blocked by the first wavelength pass filter 71.
[0252] [0252] The second and third colored lights can be high energy, which have a relatively shorter wavelength than the first colored light. As such, upon entering the first epitaxial cell 20, the second and third colored lights can induce additional light emission in the first epitaxial cell 20. In an exemplary embodiment, however, the second and third colored lights are prevented from entering the first epitaxial cell 20 by the first wavelength pass filter 71.
[0253] [0253] In an exemplary embodiment, a second wavelength 73 pass filter can be provided between the second epitaxial cell 30 and the third epitaxial cell
[0254] [0254] As described above, the third colored light can be a relatively high energy light that has a shorter wavelength than the first and second colored lights. As such, when entering the first and second epitaxial cells 20 and 30, the third colored light can induce additional emission in the first and second epitaxial cells 20 and 30. In the exemplary embodiment, however, the second filter of length passage of wave 73 prevents the third light from entering the first and second epitaxial cells 20 and 30.
[0255] [0255] The first and second pass filters of wavelength 71 and 73 can be formed in various forms, but can be formed by insulation films stacked alternately with different refractive indices. For example, the wavelength of the transmitted light can be determined by alternately stacking SiO2 and TiO2 and adjusting the thickness and stacking number of SiO2 and TiO2. Insulation films with different refractive indices can include SiO2, TiO2, HfO2, Nb2O5, ZrO2, Ta2O5 or the like.
[0256] [0256] In an exemplary embodiment, the first to the third p 25p, 35p and 45p type contact electrodes, the first to the third adhesive layers 61, 63 and 65 and the first and second wavelength filters 71 and 73 they can be standardized together in the same step of standardizing one of the first to third epitaxial cells 20, 30 and 40, or alternatively, they can be standardized in a separate step. For example, the above layers can be inclined at substantially the same or similar angle as that of the first to third epitaxial cells 20, 30 and 40. FIG. 3 shows that the first to the third contact electrodes of the type p 25p, 35p and 45p, the first to the third adhesive layers 61, 63 and 65 and the first and second wavelength filters 71 and 73 are standardized on the same angle than the first to third epitaxial cells 20, 30 and 40. However, the inventive concepts are not limited to these, and the angles of inclination from the first to the third contact electrode of the type p 25p, 35p and 45p, from the first to the third adhesive layers 61, 63 and 65 and the first and second wavelength pass filters 71 and 73 can be formed differently from the first to the third epitaxial cells 20, 30 and 40, depending on the materials, conditions for the process standardization or the like of each of the first to third contact electrodes of the type p 25p, 35p and 45p, the first to the third adhesive layers 61, 63 and 65 and the first and second filters of passage of wavelength 71 and 73.
[0257] [0257] The light-emitting stacked structure, according to an exemplary embodiment, can additionally employ several components to provide uniform high-efficiency light. For example, a stacked light-emitting structure, according to an exemplary embodiment, can have several irregularities in the light-emitting surface. For example, a stacked light-emitting structure, according to an exemplary embodiment, may have irregularities formed on the upper surface of at least one n-type semiconductor layer of the first to third epitaxial cells 20, 30 and 40.
[0258] [0258] The irregularities of each epitaxial cell can be formed selectively. For example, irregularities can be provided in the first epitaxial cell 20 and irregularities can be provided in the first and third epitaxial cells 20 and 40, and irregularities can be provided in the first to third epitaxial cells 20, 30 and 40. The irregularities in each of the epitaxial cells can be provided in a n-type semiconductor layer corresponding to the emission surface of each of the epitaxial cells.
[0259] [0259] The irregularities formed in the epitaxial cells can increase the efficiency of light emission and can be provided in several ways, such as a polygonal pyramid, a hemisphere or planes with surface roughness in a random arrangement. Irregularities can be textured through various engraving processes or can be formed using a standardized sapphire substrate.
[0260] [0260] In an exemplary embodiment, the first to third colored lights of the first to third epitaxial cells 20, 30 and 40 can have different light intensities and this difference in intensity can lead to differences in visibility. For example, the efficiency of light emission can be improved by the selective formation of irregularities in the light-emitting surface of the first to third epitaxial cells 20, 30 and 40, which results in reducing the differences in visibility between the first and the third third colored lights. The colored light corresponding to the red and / or blue color may have less visibility than the green color; in this case, the first epitaxial cell 20 and / or the third epitaxial cell 40 can be textured to reduce the difference in visibility. Particularly, in the case of red light, since the light can be supplied from the lowest part of the light-emitting cells, the light intensity can be small and the light efficiency can be increased by the formation of irregularities on the surface top of it.
[0261] [0261] The light-emitting stacked structure with the structure described above may be able to express multiple colors and therefore can be employed as a pixel in a display device. In the following exemplary embodiments, a display device will be described as including the stacked light-emitting structure described above.
[0262] [0262] FIG. 4 is a plan view of a display apparatus according to an exemplary embodiment, and FIG. 5 is an enlarged plan view showing a portion P1 of FIG. 4.
[0263] [0263] Referring to FIGS. 4 and 5, the display device 100, according to an exemplary embodiment, can display any visual information such as text, video, photographs, images of two or three dimensions, or the like.
[0264] [0264] The display device 100 can take various forms, including a closed polygon that includes a straight side, such as a rectangle, or a circle, an ellipse or the like, or that includes a curved side, or a semicircle or semi-ellipse this includes a combination of straight and curved sides. In an exemplary embodiment, the display device will be described as having substantially a rectangular shape.
[0265] [0265] The display device 100 has a plurality of pixels 110 for displaying images. Each of the pixels 110 can be a minimum unit to display the image. Each pixel 110 includes the stacked light-emitting structure with the structure described above and can emit white light and / or colored light.
[0266] [0266] In an exemplary embodiment, each pixel includes a first pixel 110R that emits red light, a second pixel 110G that emits green light and a third pixel 110B that emits blue light. The first to third pixels 110R, 110G and 110B can correspond to the first to third epitaxial cells 20, 30 and
[0267] [0267] Pixels 110 are arranged in a matrix. As used here, pixels with a matrix arrangement may refer to the pixels being arranged in a line along the line or column, or that pixels 110 are generally arranged along the lines and columns, with certain modifications in detail, like pixels 110 being arranged in a zigzag shape, for example.
[0268] [0268] FIG. 6 is a structural diagram of a display device, according to an exemplary embodiment.
[0269] [0269] Referring to FIG. 6, the display apparatus 100 according to an exemplary embodiment includes a timing controller 350, a scan driver 310, a data driver 330, a spinning unit and pixels. Each of the pixels can be individually connected to the scan driver 310, data driver 330 or similar via a piece of wiring.
[0270] [0270] The timing controller 350 receives various control signals and image data necessary to drive the display device from the outside (for example, a system for transmitting image data). The timing controller 350 rearranges the received image data and transmits the image data to the data driver 330. In addition, the timing controller 350 generates scan control signals and data control signals necessary to drive the image driver. scan 310 and data driver 330 and transmits the scan control signals and data control signals that are generated to scan driver 310 and data driver 330.
[0271] [0271] Scan driver 310 receives scan control signal from timing controller 350 and generates a corresponding scan signal. The data driver 330 receives data control signal and image data from the timing controller 350 and generates corresponding data signals.
[0272] [0272] The wiring unit includes a plurality of signal lines. The wiring part specifically includes the scan lines 130 that connect the scan driver 310 and the pixels and data lines 120 connecting the data driver 330 and the pixels. The scan lines 130 can be connected to the respective pixels and, consequently, the scan lines 130 corresponding to the respective pixels are indicated with the first to the third scan lines 130R, 130G and 130B (hereinafter, collectively referred to as '130').
[0273] [0273] In addition, the wiring unit includes lines connecting between the timing controller 350 to the scanning driver 310, the timing controller 350 and the data driver 330 or other components and transmitting the signals.
[0274] [0274] Scan lines 130 provide the scan signals generated from scan driver 310 to pixels. Data signals generated from data driver 330 are sent to data lines 120.
[0275] [0275] The pixels are connected to the scan lines 130 and the data lines 120. The pixels selectively emit light in response to the data signals provided from the data lines 120 when the scan signals are provided from the data lines scan 130. For example, during each frame period, each pixel emits light with the corresponding luminance for the input data signals. The pixels provided with the data signals corresponding to the luminance of black can display black, not emitting light during the corresponding frame period.
[0276] [0276] In an exemplary mode, pixels can be activated as either passive or active. When the display device is activated in an active manner, the display device can be supplied with the first and second pixel power in addition to the scan signals and the data signals.
[0277] [0277] FIG. 7 is a one-pixel circuit diagram on a passive display device. The pixel can be one of the pixels, for example, one of the pixels R, G, B and FIG. 7 shows the first 110R pixel as an example. Since the second and third pixels can be triggered in substantially the same way as the first pixel, the circuit diagrams of the second and third pixels will be omitted to avoid redundancy.
[0278] [0278] Referring to FIG. 7, the first pixel 110R includes an emitting element 150 connected between the scanning line 130 and the data line 120. The light emitting element 150 can correspond to the first epitaxial cell 20. The epitaxial cell 20 emits light with a luminance corresponding to the magnitude of the applied voltage when a voltage equal to or greater than a threshold voltage is applied between the p-type semiconductor layer and the n-type semiconductor layer. In particular, the emission of the first pixel 110R can be controlled by controlling the voltages of the scan signal applied to the first scan line 130R and / or the data signal applied to the data line
[0279] [0279] FIG. 8 is a circuit diagram illustrating a first pixel of a display device of the active type.
[0280] [0280] When the display device is of the active type, the first pixel 110R can be supplied with the first and the second pixel power (ELVDD and ELVSS) in addition to the scan signal and the data signal.
[0281] [0281] Referring to FIG. 8, the first pixel 110R includes a light emitting element 150 and a piece of the transistor connected thereto.
[0282] [0282] The light-emitting element 150 corresponds to the first epitaxial cell 20 and the p-type semiconductor layer of the light-emitting element 150 can be connected to the first pixel energy source ELVDD through the transistor part and the semiconductor layer of the type n cannot be connected to a second ELVSS pixel power source. The first ELVDD pixel power source and the second ELVSS pixel power source can have different potentials. For example, the second sub-pixel ELVSS power source smaller than the first ELVDD pixel power source, for at least the threshold voltage of the light-emitting element 150. Each of these light-emitting elements 150 emits a luminance corresponding to a current drive controlled by the transistor part.
[0283] [0283] According to an exemplary embodiment, the transistor part includes the first and second M1 and M2 transistors and a Cst storage capacitor. However, inventive concepts are not limited and the configuration of the circuit of a pixel can be modified in several ways.
[0284] [0284] The source electrode of the first M1 transistor (for example, a switching transistor) is connected to data line 120, and a drain electrode is connected to a first node N1. In addition, a gate electrode from the first M1 transistor is connected to the first 130R scan line. The first transistor M1 can be connected when a scan signal having a voltage capable of connecting the first transistor M1 is supplied from the first scan line 130R to data line 120, to electrically connect the first node N1. For example, the data signal from the corresponding frame is supplied to data line 120 and therefore the data signal is transmitted to the first node N1. The data signal transmitted to the first node N1 is loaded into the storage capacitor Cst.
[0285] [0285] The source electrode of the second transistor M2 is connected to the first pixel energy source ELVDD and a drain electrode is connected to the n-type semiconductor layer of the light emitting element 150. The port electrode of the second transistor M2 is connected to the first N1 node. The second transistor M2 controls an amount of drive current supplied to the light-emitting element 150 to match the voltage of the first node N1.
[0286] [0286] One electrode of the Cst storage capacitor is connected to the first ELVDD subpixel power source, and the other electrode is connected to the first N1 node. The storage capacitor Cst carries a voltage corresponding to the data signal supplied to the first node N1 and keeps the voltage charged until the data signal of the next frame is supplied.
[0287] [0287] FIG. 8 shows a part of the transistor including two transistors; however, the inventive concepts are not limited to these, and several modifications may apply to the structure of the transistor part. For example, the transistor part may include more transistors, capacitors or the like, each with several structures.
[0288] [0288] Pixels can be implemented in various structures within the scope of inventive concepts. In the following, a pixel will be described as having a passive matrix type pixel.
[0289] [0289] FIG. 9 is a plan view of a pixel according to an exemplary embodiment, and FIGS. 10A and 10B are cross-sectional views taken along lines I-I 'and II-II' of FIG. 9, respectively.
[0290] [0290] Referring to FIGS. 9, 10A and 10B, a pixel, according to an exemplary embodiment, a light-emitting region in which a plurality of epitaxial cells are stacked and a peripheral region surrounding the light-emitting region. The plurality of epitaxial cells can include the first to the third epitaxial cells 20, 30 and 40.
[0291] [0291] The pixel, according to an exemplary modality, has a light-emitting region in which a plurality of epitaxial cells are stacked. At least one side of the light-emitting region is provided with a contact to connect the wiring piece to the first and third epitaxial cells 20, 30 and 40. The contact includes the first and second common contacts 50GC and 50BC for the application of a voltage common to the first and third epitaxial cells 20, 30 and 40, a first contact 20C to provide a light emitting signal for the first epitaxial cell 20, a second contact 30C to provide a light emitting signal to the second epitaxial cell 30 and a third 40C contact to provide a light emitting signal for the third epitaxial cell
[0292] [0292] In an exemplary embodiment, the stacked structure can vary depending on the polarity of the semiconductor layers from the first to the third epitaxial cells 20, 30m and 40 to which the common voltage is applied. In the following, the stacked structure will be described as being applied at a voltage common to a p-type semiconductor layer. In particular, the first to the third common contact electrodes will be described as corresponding to the first to the third type p contact electrodes, respectively.
[0293] [0293] In an exemplary mode, the first and second common contacts 50GC and 50BC, and the first to third contacts 20C, 30C and 40C can be provided in various positions. For example, when the stacked light-emitting structure has a substantially square shape, the first and second common contacts 50GC and 50BC and the first to third contacts 20C, 30C and 40C can be arranged in regions corresponding to the corresponding matrices of the square in one plan view. However, the positions of the first and second common contacts 50GC and 50BC and from the first to the third contacts 20C, 30C and 40C are not limited to these, and several modifications are applicable, according to the shape of the light-emitting stacked structure.
[0294] [0294] The plurality of epitaxial cells includes the first to third epitaxial cells 20, 30 and 40. The first to third epitaxial cells 20, 30 and 40 are connected with the first to third light-emitting signal lines to provide light emitting signals. light to each of the first to third epitaxial cells 20, 30 and 40 and common line to provide a common voltage for each of the first to third epitaxial cells 20, 30 and 40. The first to third lines of light emitting signal may correspond the first to third scan lines 130R, 130G and 130B, and the common line can correspond to data line 120. Therefore, the first to third scan lines 130R, 130G and 130B and data line 120 are connected to the first to the third epitaxial cells 20, 30 and 40, respectively.
[0295] [0295] Referring to FIG. 9, the first to third scan lines 130R, 130G and 130B can extend in a first direction (for example, in a horizontal direction). Data line 120 can extend in a second direction, crossing the first to third scan lines 130R, 130G and 130B (for example, in a vertical direction). However, the extension directions of the first to third scan lines 130R, 130G and 130B and data line 120 are not limited to these, and several modifications are applicable, depending on the arrangement of the pixels.
[0296] [0296] Data line 120 and the first type 25p contact electrode can extend in a second direction that crosses the first direction, while providing a common voltage to the type p semiconductor layer of the first epitaxial cell 20. Therefore, data line 120 and the first p-type 25p contact electrode can be substantially the same component. From now on, the first contact electrode of type p 25p can be referred to as data line 120, or vice versa.
[0297] [0297] An ohmic electrode 25p 'for ohmic contact between the first type 25p contact electrode and the first epitaxial cell 20 are provided in the light emitting region provided with the first type 25p contact electrode. A plurality of ohmic 25p 'electrodes can be provided. The ohmic electrode 25p 'is provided for ohmic contact and can include a variety of materials. For example, the ohmic electrode 25p 'corresponding to the ohmic electrode of type p 25p' may include an Au / Zn alloy or an Au / Be alloy. In this case, since the material of the ohmic electrode 25p 'has lower reflectivity than Ag, Al, Au or the like, additional reflective electrodes can be further arranged. As an additional reflective electrode, Ag, Au or the like can be used, and Ti, Ni, Cr, Ta or the like can be arranged as a buffer layer for adhesion to the adjacent components. In that case, the buffer layer can be finely deposited on the upper and lower surfaces of the reflector electrode, including Ag, Au or the like.
[0298] [0298] The first scan line 130R is connected to the first epitaxial cell 20 through the first contact hole CH1, and the data line 120 is connected through the ohmic electrode 25p '. The second scan line 130G is connected to the second epitaxial cell 30 through the second contact hole CH2 and the data line 120 is connected through the contact holes 4ath and 4bth CH4a and CH4b. The third scan line 130B is connected to the third epitaxial cell 40 through the third contact hole CH3, and the data line 120 is connected through the contact holes 5ath and 5bth CH5a and CH5b.
[0299] [0299] An adhesive layer, a contact electrode, a wavelength pass filter or the like are provided between substrate 10 and the first to third epitaxial cells 20, 30 and 40, respectively. In the following, a pixel, according to an exemplary embodiment, will be described with reference to a stacking order.
[0300] [0300] According to the exemplary embodiment, a first epitaxial cell 20 is provided on substrate 10 with an adhesive layer 61 interposed between them. The first epitaxial cell 20 may include a p-type semiconductor layer, an active layer and a n-type semiconductor layer arranged in sequence from the bottom to the top.
[0301] [0301] An insulation film 81 is stacked on a lower surface of the first epitaxial cell 20 to face the substrate 10. The insulation film 81 formed on the lower surface of the first epitaxial cell 20 can include a material that transmits or absorbs light. A plurality of contact holes are formed in the insulation film 81. The contact holes are provided with an ohmic 25p 'electrode in contact with the p-type semiconductor layer of the first epitaxial cell
[0302] [0302] When viewed from the flat view, the first p 25p contact electrode can be provided in such a way that the first p 25p contact electrode overlaps the first epitaxial cell 20 or, more particularly, overlaps the region light emitting from the first epitaxial cell 20, covering most or all of the light emitting region. The first p 25p contact electrode can include a reflective material, so that the first p 25p contact electrode can reflect the light from the first epitaxial cell 20. Insulation film 81 can also be formed to have a property reflective to facilitate the reflection of light from the first epitaxial cell 20. For example, the insulation film 81 may have an omnidirectional reflector (ODR) structure.
[0303] [0303] The material of the first layer of type 25p contact electrode is selected from metals with high reflectivity to the light emitted from the first epitaxial cell 20, to maximize the reflectivity of the light emitted from the first epitaxial cell 20 For example, when the first epitaxial cell 20 emits red light, a metal with high reflectivity to red light, for example, Au, Al, Ag or the like can be used as the material for the first p-type contact electrode layer 25p. Au does not have high reflectivity for the light emitted by the second and third epitaxial cells 30 and 40 (for example, green light and blue light) and therefore can reduce a mixture of colors by the light emitted by the second and third epitaxial cells 30 and 40 .
[0304] [0304] The third contact electrode of type n 21n is provided on an upper surface of the first epitaxial cell
[0305] [0305] The first contact electrode of type n 21n is supplied in a region corresponding to the first contact 20C and may include a conductive material.
[0306] [0306] The second adhesive layer 63 is provided on the first epitaxial cell 20. The first wavelength path filter 71, the second p 35p contact electrode and the second epitaxial cell 30 are supplied sequentially on the second adhesive layer 63 The second epitaxial cell 30 may include an n-type semiconductor layer, an active layer and a p-type semiconductor layer arranged sequentially from the bottom to the top.
[0307] [0307] The first wavelength pass filter 71 is provided on the top surface of the first epitaxial cell 20 to cover substantially the entire light-emitting region of the first epitaxial cell 20.
[0308] [0308] In an exemplary embodiment, the region corresponding to the first contact 20C of the second epitaxial cell 30 is removed, thus exposing a portion of the upper surface of the first contact electrode of type n 21n. In addition, the second epitaxial cell 30 may have a smaller area than the second p 35p contact electrode. The region corresponding to the first common contact 50GC is removed from the second epitaxial cell 30, thus exposing a portion of the upper surface of the second type 35p contact electrode.
[0309] [0309] The third adhesive layer 65 is provided on the second epitaxial cell 30. The second wavelength path filter 73 and the third contact electrode of type p 45p are supplied sequentially on the third adhesive layer 65. The third epitaxial cell 40 is supplied on the third type 45p contact electrode. The third epitaxial cell 40 may include a p-type semiconductor layer, an active layer and an n-type semiconductor layer stacked sequentially from the bottom to the top.
[0310] [0310] The third epitaxial cell 40 may have an area smaller than the second epitaxial cell 30. The third epitaxial cell 40 may have an area smaller than the third contact electrode of type p 45p. The region corresponding to the second common contact 50BC is removed from the third epitaxial cell 40, thereby exposing a portion of the upper surface of the third type 45 p contact electrode.
[0311] [0311] The first optically non-transmissive film 83 covering the stacked structure of the first to third epitaxial cells 20, 30 and 40 is provided in portions of the sides and on the upper surfaces of the first to third epitaxial cells 20, 30 and 40. The first film optically non-transmissive 83 can include and is not limited to various organic / inorganic insulating materials. For example, the first optically non-transmissive film 83 may be a DBR or an organic polymer film with a black color. In an exemplary embodiment, a floating metal reflective film can also be provided in the first optically non-transmissive film 83. In an exemplary embodiment, the optically non-transmissive film can be formed by depositing two or more insulation films with different refractive indexes than one other.
[0312] [0312] The first contact hole CH1 is formed in the first optically non-transmissive film 83 to expose an upper surface of the first type 21n contact electrode provided in the first contact 20C.
[0313] [0313] A first scan line 130R is provided on the first optically non-transmissive film 83. The first scan line 130R is connected to the first contact electrode of type n 21n through the first contact hole CH1.
[0314] [0314] A second optically non-transmissive film 85 is provided in the first optically non-transmissive film 83. The second optically non-transmissive film 85 is also provided in portions of the sides and on the upper surfaces of the first to third epitaxial cells 20, 30 and 40, covering the stacked structure of the first to third epitaxial cells 20, 30 and 40. The second optically non-transmissive film 85 may include substantially the same or different materials as the first optically non-transmissive film 83. The second optically non-transmissive film 85 may also be a DBR or an organic polymer film with a black color. In an exemplary embodiment, a floating metal reflective film may also be provided in the second optically non-transmissive film 85. In an exemplary embodiment, the optically non-transmissive film may be formed by depositing two or more insulation films with different refractive indices than one other.
[0315] [0315] The second and third scan lines 130G and 130B and the first and second bridge electrodes BRG and BRB are provided on the second optically non-transmissive film 85. The second optically non-transmissive film 85 is provided with a second contact orifice CH2 to expose an upper surface of the second epitaxial cell 30 in the second contact 30C, that is, expose the n-type semiconductor layer of the second epitaxial cell 30, a third contact hole CH3 to expose an upper surface of the third epitaxial cell 40 in the third contact 40C, that is, exposing an n-type semiconductor layer of the third epitaxial cell 40, 4ath and 4bth contact holes CH4a and CH4b to expose an upper surface of the first type 25p contact electrode and an upper surface of the second electrode of contact contact type p 35p, in the first common contact 50GC and contact holes 5ath and 5bth CH5a and CH5b to expose an upper surface of the first tip contact electrode the p 25p and an upper surface of the third contact electrode type p 45p, in the second common contact 50BC.
[0316] [0316] The second 130G scan line is connected to the n-type semiconductor layer of the second epitaxial cell 30 through the second contact hole CH2. The third scan line 130B is connected to the n-type semiconductor layer of the third epitaxial cell 40 through the third contact hole CH3. Data line 120 is connected to the second type 35p contact electrode through the contact holes 4ath and 4bth CH4a and CH4b and the first BRG bridge electrode. Data line 120 is also connected to the third p 45p contact electrode through the 5ath and 5bth CH5a and CH5b contact holes and the second BRB bridge electrode.
[0317] [0317] FIGS. 9 to 10B show that the second and third scan lines 130G and 130B are electrically connected to the n-type semiconductor layer of the second and third epitaxial cells 30 and 40 in direct contact with each other. However, the inventive concepts are not limited to these, the second and third type n contact electrodes can still be supplied between the second and third scan lines 130G and 130B and the type n semiconductor layers of the second and third epitaxial cells 30 and 40.
[0318] [0318] Irregularities can be selectively provided on the upper surfaces of the first to third epitaxial cells 20, 30 and 40, that is, on the upper surfaces of the first to third epitaxial cells 20, 30 and 40. Each of the irregularities can only be provided on a portion corresponding to the light-emitting region or can be provided over substantially the entire upper surface of the respective semiconductor layers.
[0319] [0319] In an exemplary embodiment, the first and second optically non-transmissive films 83 and 85 can completely cover the sides of the first to third epitaxial cells 20, 30 and 40. The first and second optically non-transmissive films 83 and 85 can cover a portion of the upper surface of the third epitaxial cell 40. Therefore, the first and second optically non-transmissive films 83 and 85 are not provided in the light-emitting region, so that the light emitted from the first to the third epitaxial cells can travel in the upper direction.
[0320] [0320] In addition, in an exemplary embodiment, an additional metal-based optically non-transmissive film may additionally be provided on the sides of the first and / or the second optically non-transmissive film 83 and 85 that correspond to the sides of the pixels. The additional optically non-transmissive film is an additional light blocking film that includes an absorbent or reflective material, which is provided to prevent light from the first to third epitaxial cells 20, 30 and 40 from appearing on the sides of the pixels.
[0321] [0321] In an exemplary embodiment, the additional optically non-transmissive film can be formed as a single or multilayer metal. For example, the additional optically non-transmissive film can be formed by a variety of materials, including metals such as Al, Ti, Cr, Ni, Au, Ag, Ti, Sn, Ni, Cr, W, Cu or others, or alloys of the same. The additional optically non-transmissive film may be provided on the sides of the first and / or the second insulation film 83 and 85 as a separate layer formed of a material, such as metal or alloy thereof.
[0322] [0322] The additional optically non-transmissive film can be formed separately from the first to third scan lines 130R, 130G and 130B and the first and second bridge electrodes BRG and BRB, on the same layer and using substantially the same material during the same process to form at least one of the first to third scan lines 130R, 130G and 130B and the first and second bridge electrodes BRG and BRB. In this case, the optically non-transmissive film can be electrically isolated from the first to the third scan lines 130R, 130G and 130B and the first and second bridge electrodes BRG and BRB.
[0323] [0323] In an exemplary embodiment, the additional optically non-transmissive film can be provided such that it extends laterally from at least one of the first to third scan lines 130R, 130G and 130B and the first and second BRG bridge electrodes and BRB. In this case, the optically non-transmissive film extending from one of the first to the third scan lines 130R, 130G and 130B and the first and second bridge electrodes BRG and BRB may not be electrically connected to other conductive components.
[0324] [0324] The pixel that has the structure described above can be manufactured by stacking the first to third epitaxial cells 20, 30 and 40 on the substrate 10 sequentially and standardizing it, which will be described in detail below with reference to the figures.
[0325] [0325] FIGS. 11 to 21 are plan views showing sequentially a method of making a pixel on a substrate. FIGS. 12A and 12B to 22A and 22B are seen in cross section taken along line I-I 'and line II-II' of the corresponding figures, such as FIGS. 11 and 21, respectively.
[0326] [0326] Referring to FIGS. 11, 12A and 12B, the first to third epitaxial cells 20, 30 and 40 are formed sequentially on substrate 10 and the third epitaxial cell 40 is standardized.
[0327] [0327] To sequentially form the first to third epitaxial cells 20, 30 and 40 on substrate 10, the first epitaxial cell 20 and the ohmic electrode 25p 'are formed on a first temporary substrate. In an exemplary embodiment, the first temporary substrate can be a semiconductor substrate, such as a GaAs substrate to form the first epitaxial cell 20. The first epitaxial cell 20 is manufactured by stacking the n-type semiconductor layer, the active layer and the semiconductor layer. of type p on the first temporary substrate. The insulation film 81 that has a contact hole is formed in the first temporary substrate and the ohmic electrode 25p 'is formed inside the contact hole of the insulation film
[0328] [0328] The ohmic electrode 25p 'is formed by forming the insulation film 81 on the first temporary substrate, applying photoresist, standardizing the photoresistor, depositing a material from the ohmic electrode 25p' on the standardized photoresistor and then removing the photoresistor pattern . However, the method of forming the ohmic 25p 'electrode is not limited to this. For example, insulation film 81 can be formed by forming insulation film 81, standardizing insulation film 81 by photolithography, forming the ohmic electrode film 25p 'with the material of the ohmic electrode film 25p' and standardizing the 25p 'ohmic electrode film by photolithography.
[0329] [0329] The first p 25p type contact electrode layer (also serving as data line 120) is formed on the first temporary substrate on which the ohmic electrode 25p 'is formed. The first p 25p type contact electrode layer may include a reflective material. The first p 25p contact electrode layer can be formed by, for example, depositing a metal material and then standardizing it using photolithography.
[0330] [0330] The first epitaxial cell 20 formed on the first temporary substrate is inverted and fixed to substrate 10 through the first adhesive layer 61 interposed between them.
[0331] [0331] After the first epitaxial cell 20 is deposited on substrate 10, the first temporary substrate is removed. The first temporary substrate can be removed by various methods, such as wet etching, dry etching, physical removal, laser removal or the like.
[0332] [0332] After removing the first temporary substrate, the first n 21n contact electrode is provided on an upper surface of the first epitaxial cell 20. The first n 21n contact electrode can be formed by depositing a conductive material and then standardizing by the photolithography process.
[0333] [0333] After the elevation of the first temporary substrate, irregularities can be formed on an upper surface (type n semiconductor layer) of the first epitaxial pile 20. The irregularities can be formed by textures with various engraving processes. For example, irregularities can be formed by various methods, such as dry engraving using a microphotography process, wet engraving using a crystal feature, texturing using a physical method, such as sandblasting, ion beam engraving, texturing with based on the difference in the recording rates of block copolymers or the like.
[0334] [0334] The second epitaxial cell 30, the second p 35p contact electrode layer and the first wavelength pass filter 71 are formed on a second separate temporary substrate.
[0335] [0335] The second temporary substrate may be a sapphire substrate. The second epitaxial cell 30 can be manufactured by forming the n-type semiconductor layer, the active layer and the p-type semiconductor layer on the second temporary substrate.
[0336] [0336] The second epitaxial cell 30 formed on the second temporary substrate is inverted and attached to the first epitaxial cell 20 through the second adhesive layer 63 interposed between them.
[0337] [0337] After connection, the second temporary substrate is removed. The second temporary substrate can be removed by various methods, such as wet etching, dry etching, physical removal, laser removal or the like.
[0338] [0338] After the elevation of the second temporary substrate, irregularities can be formed on an upper surface (type n semiconductor layer) of the second epitaxial cell 30. The irregularities can be textured through various engraving processes, or can be formed using a sapphire substrate standardized for the second temporary substrate.
[0339] [0339] The third epitaxial cell 40, the third p 45p contact electrode layer and the second wavelength pass filter 73 are formed on a third separate temporary substrate.
[0340] [0340] The third temporary substrate may be a sapphire substrate. The third epitaxial cell 40 can be manufactured by forming the n-type semiconductor layer, the active layer and the p-type semiconductor layer on the third temporary substrate.
[0341] [0341] The third epitaxial cell 40 formed on the third temporary substrate is inverted and attached to the second epitaxial cell 30 through the third adhesive layer 65 interposed between them.
[0342] [0342] After connection, the third temporary substrate is removed. The temporary third substrate can be removed by various methods, such as wet etching, dry etching, physical removal, laser removal or the like. After the elevation of the third temporary substrate, irregularities can be formed on the upper surface (semiconductor layer type n) of the third epitaxial cell 40. The irregularities can be textured through various engraving processes, or they can be formed using a standard sapphire substrate for the third temporary substrate.
[0343] [0343] Next, the third epitaxial cell 40 is standardized. Portions of the third epitaxial cell 40, except for the light-emitting region, are removed. In particular, the portions corresponding to the first and second contacts 20C and 30C and the first and second common contacts 50GC and 50BC are removed. As such, a portion of the upper surface of the third p 45p contact electrode is exposed to the outside in the second common contact 50BC. The third epitaxial cell 40 can be removed by various methods, such as wet recording or dry recording using photolithography, and the third p 45p contact electrode can function as a recording stopper.
[0344] [0344] According to an exemplary embodiment, the side of the third epitaxial cell 40 is obliquely standardized with respect to one side of the substrate 10, and the angle formed between the third epitaxial cell 40 and one side of the substrate 10 can be between about 45 degrees and about 85 degrees.
[0345] [0345] The third p 45p contact electrode, the second wavelength filter 73 and the third adhesive layer 65 are then standardized. As such, a portion of the upper surface of the second epitaxial cell 30 is exposed.
[0346] [0346] The third p 45p type contact electrode, the second pass filter 73 and the third adhesive layer 65 can be removed by various methods, such as wet etching or dry etching using photolithography.
[0347] [0347] Referring to FIGS. 13, 14A and 14B, a portion of the second epitaxial cell 30 is removed, exposing a portion of the upper surface of the second type 35p contact electrode in the second common contact 50GC to the outside. The third p 45p type contact electrode can act as an attack stopper during recording.
[0348] [0348] The side of the second epitaxial cell 30 is obliquely standardized with respect to one side of the substrate 10, and the angle formed between the second epitaxial cell 30 and one side of the substrate 10 can be between about 45 degrees and about 85 degrees .
[0349] [0349] Then, portions of the second p 35p type contact electrode, the first wavelength pass filter 71 and the second adhesive layer 63 are recorded. Accordingly, the upper surface of the first n 21n contact electrode is exposed in the first contact 20C, and the upper surface of the first epitaxial cell 20 is exposed in portions other than the light-emitting region.
[0350] [0350] The second epitaxial cell 30, the second p 35p contact electrode, the first wavelength pass filter 71 and the second adhesive layer 63 can be removed by various methods, such as wet etching or dry etching using photolithography.
[0351] [0351] Referring to FIGS. 15, 16A and 16B, the first epitaxial cell 20 and the insulation film 81 are removed from the region, excluding the light-emitting region. The upper surface of the first p 25p type contact electrode is exposed in the first and second common contacts 50GC and 50BC.
[0352] [0352] The side of the first epitaxial cell 20 is obliquely standardized with respect to one side of the substrate 10, and the angle formed between the first epitaxial cell 20 and one side of the substrate 10 can be between about 45 degrees and about 85 degrees .
[0353] [0353] The angles formed by the first to third epitaxial cells 20, 30 and 40 with respect to a substrate surface can be substantially the same or different from each other, although substantially the same angles are illustrated in the figure for convenience of explanation. The components, excluding the first to third epitaxial cells 20, 30 and 40, for example, the first and second contact electrodes of the type p 25p and 35p, the first and second adhesive layers 61 and 63 and the first and second Wavelength pass filters 71 and 73 can be obliquely patterned to have a predetermined angle to one side of the substrate. According to another exemplary embodiment, the angles formed by the first and second contact electrodes of the type p 25p and 35p, the first and second adhesive layers 61 and 63, the first and the second wavelength filters 71 and 73 with respect to one side of the substrate are not limited to them, and therefore the angles may vary depending on the components engraved together in the same process, or they may have angles individually different from each other, provided that the angle formed between each of the components and one side of the substrate can be between about 45 degrees and about 85 degrees.
[0354] [0354] Referring to FIGS. 17, 18A and 18B, the first optically non-transmissive film 83 is formed on the front side of the substrate 10. Then, after lifting the first optically non-transmissive film 83 from the top surface of the substrate 10, which corresponds to the light-emitting region, the first to third contact holes CH1, CH2 and CH3, contact holes 4ath and 4bth CH4a and CH4b and contact holes 5ath and 5bth CH5a and CH5b are formed.
[0355] [0355] After deposition, the first optically non-transmissive film 83 can be standardized by various methods, such as wet recording or dry recording using photolithography.
[0356] [0356] Referring to FIGS. 19, 20A and 20B, the first scan line 130R is formed on the first standard optically non-transmissive film 83. The first scan line 130R is connected to the first contact electrode of type n 21n through the first contact hole CH1 at the first contact 20C. The first 130R scan line can be formed in several ways. For example, the first 130R scan line can be formed by photolithography.
[0357] [0357] Next, the second optically non-transmissive film 85 is formed at the front of the substrate 10. Then, preferably simultaneously with the elevation of the first optically non-transmissive film 83 from the upper surface of the substrate 10 which corresponds to the light-emitting region. , the second and third contact holes CH2 and CH3, the contact holes 4ath and 4bth CH4a and CH4b, and the contact holes 5ath and 5bth CH5a and CH5b are formed. After deposition, the second optically non-transmissive film 85 can be standardized by various methods, such as wet recording or dry recording using photolithography.
[0358] [0358] Referring to FIGS. 21, 22A and 22B, the second scan line 130G, the third scan line 130B, the first BRG bridge electrode and the second BRB bridge electrode are formed in the second standardized, non-transmissive 85 film.
[0359] [0359] The second 130G scan line is connected to the n-type semiconductor layer of the second epitaxial cell 30 through the second contact hole CH2 on the second contact 30C. The third scan line 130B is connected to the n-type semiconductor layer of the third epitaxial cell 40 through a third contact hole CH3 in the third contact 40C. The first BRG bridge electrode pad is connected to the first type 25p contact electrode through the contact holes 4ath and 4bth CH4a and CH4b in the fourth common contact 50GC. The second BRB bridge electrode is connected to the first type 25p contact electrode through the 5ath and 5bth contact holes CH5a and CH5b in the second common contact 50BC.
[0360] [0360] The second scan line 130G, the third scan line 130B and the bridge electrode 120b can be formed on the second non-transmissive film 85 in various ways, for example, by photolithography.
[0361] [0361] The second scan line 130G, the third scan line 130B and the first and second bridge electrodes BRG and BRB can be formed by applying photoresist to substrate 10 on which the second optically non-transmissive film 85 is formed and standardizing the photoresist, and depositing materials from the second 130G scan line, the third 130B scan line and the bridge electrode on the standard photoresistor and then removing the photoresistor pattern.
[0362] [0362] According to an exemplary modality, the order to form the first to third scan lines 130R, 130G and 130B and the first and second bridge electrodes BRG and BRB of the spinning part is not particularly limited and can be formed in different sequences. More particularly, the second scan line 130G, the third scan line 130B and the first and second bridge electrodes BRG and BRB are described as being formed in the second optically non-transmissive film 85 during the same stage, but can be formed in a different order. For example, the first scan line 130R and the second scan line 130G can be formed first in the same step, followed by the formation of the additional insulation film and then by the third scan line 130B. Alternatively, the first scan line 130R and the third scan line 130B can be formed first in the same step, followed by the formation of the additional insulation film and then the formation of the second scan line 130G. In addition, the first and second BRG and BRB bridge electrodes can be formed together at any of the forming stages from the first to the third scan lines 130R, 130G and 130B.
[0363] [0363] In addition, in an exemplary embodiment, the contact positions of the respective epitaxial cells 20, 30 and 40 can be formed differently, in which case the positions of the first to the third scan lines 130R, 130G and 130B and the first and second bridge electrodes BRG and BRB can also be changed.
[0364] [0364] In an exemplary embodiment, an additional optically non-transmissive film may also be provided in the first optically non-transmissive film 83 or in the second optically non-transmissive film 85, in a portion corresponding to the pixel side.
[0365] [0365] As described above, in a display device, according to an exemplary embodiment, it is possible to stack a plurality of epitaxial cells sequentially and then form contacts with a spinning piece in a plurality of epitaxial cells at the same time.
[0366] [0366] A stacked light-emitting structure, according to an exemplary modality, can be modified in several ways. In the exemplary modalities below, the differences in relation to the stacked light-emitting structure described above will be described mainly to avoid redundancy.
[0367] [0367] FIG. 23 is a cross-sectional view of a stacked light-emitting structure, according to an exemplary embodiment.
[0368] [0368] Referring to FIG. 23, a light-emitting stacked structure, according to an exemplary embodiment, includes a plurality of sequentially stacked epitaxial cells and optically non-transmissive films covering the sides of the epitaxial cells and a plurality of epitaxial cells sequentially arranged on the upper surface of the substrate 10.
[0369] [0369] A plurality of epitaxial cells are stacked on the top surface of the substrate 10 in the order of the third epitaxial cell 40, the second epitaxial cell 30 and the first epitaxial cell 20.
[0370] [0370] Substrate 10 may be formed from an optically transmissive insulation material. As used in this document, substrate 10 being "optically transmissive" not only refers to a transparent substrate that transmits all light, but also to a semi-transparent or partially transparent substrate that transmits only a light of predetermined wavelength or transmits only one portion of a light of predetermined wavelength or similar.
[0371] [0371] Substrate 10 can allow the third epitaxial cell 40 to grow on it. For example, substrate 10 can be a sapphire substrate. However, the inventive concepts are not limited to a particular type of substrate 10 and can be any type of substrate, as long as the epitaxial cell can be grown on it and has transmissive and insulating optical properties. Examples of the substrate 10 material include glass, quartz, organic polymer, organic / inorganic composite and so on. In an exemplary embodiment, substrate 10 may further include a spinning piece that can provide a light-emitting signal and a common voltage for the respective epitaxial cells. As such, substrate 10 can be supplied as a printed circuit board or as a composite substrate with a spinning piece and / or a drive element formed of glass, silicon, quartz, organic polymer or organic / inorganic composite.
[0372] [0372] Each of the epitaxial cells emits light in the rear direction of the substrate 10, as shown in FIG. 23. The light emitted from an epitaxial cell is passed through another epitaxial cell located in the light path and travels to the rear direction. In this case, the return direction corresponds to a direction along which the first to third epitaxial cells 20, 30 and 40 are stacked.
[0373] [0373] In the exemplary embodiment, the first epitaxial cell 20 can emit a first colored light L1, the second epitaxial cell 30 can emit a second colored light L2 and the third epitaxial cell 40 can emit the third colored light L3. The first to third colored lights L1, L2 and L3 correspond to a different colored light from each other, and the first to the third colored lights L1, L2 and L3 can be colored lights of different wavelength bands from each other, which decrease sequentially wavelengths. In particular, the first to third colored lights L1, L2 and L3 may have different wavelength bands,
[0374] [0374] An optically non-transmissive film 80 is provided on the sides of the first to third epitaxial cells 20, 30 and
[0375] [0375] In an exemplary embodiment, the side of each epitaxial cell has an inclined shape in relation to one side of the substrate 10. According to an exemplary embodiment, an angle between the sides of the first to third epitaxial cells 20, 30 and 40 and one side of the substrate 10 is greater than about 0 degrees and less than about 90 degrees. For example, when the angles between the sides of the first to third epitaxial cells 20, 30 and 40 and one side of the substrate is from the first to the third angle θ1, θ2 and θ3, from the first to the third angle θ1, θ2 and θ3 can have values in a range of about 45 degrees to about 85 degrees, respectively.
[0376] [0376] When the sides of the first to third epitaxial cells 20, 30 and 40 have a predetermined slope, the optically non-transmissive film 80 can be easily formed. In addition, in an exemplary embodiment, each of the epitaxial cells has a tapered shape at a predetermined angle, which can maximize the effect of light reflection by the optically non-transmissive film 80. In particular, according to an exemplary embodiment, it is it is possible to easily adjust the angles of the sides of the first to the third epitaxial cells 20, 30 and 40, to increase the efficiency of extracting the light emitted from the first to the third epitaxial cells 20, 30 and 40.
[0377] [0377] In an exemplary embodiment, the angles between the sides of each of the first to third epitaxial cells 20, 30 and 40 and one side of the substrate 10 can be substantially the same or different from each other. For example, between the angles formed between the sides of the first to third epitaxial cells 20, 30 and 40 and one side of the substrate 10, the first angle θ1, the second angle θ2 and the third angle θ3 may be different from each other, or alternatively, the second angle θ2 and the third angle θ3 can be substantially the same and different from the first angle θ1.
[0378] [0378] In the light-emitting stacked structure, according to an exemplary modality, the signal lines to apply emitting signals to the respective epitaxial cells are connected independently and, consequently, the respective epitaxial cells can be activated independently and, thus, the structure stacked light emitter can implement various colors, according to the light emission in each of the epitaxial cells. In addition, epitaxial cells for emitting light of different wavelengths are superimposed vertically on top of each other and therefore can be formed in a narrow area. In addition, as the sides of the epitaxial cells are slanted, it is possible to easily form the non-transmissive film with sufficient thickness, and the non-transmittance film can prevent the phenomenon in which the light emitted by a given pixel affects the adjacent pixels or which color is mixed with the light emitted by the adjacent pixels.
[0379] [0379] FIG. 24 is a cross-sectional view of a stacked light-emitting structure including a wiring part, according to an exemplary embodiment. In FIG. 24, the inclined shapes of each of the epitaxial cells and the insulation films shown in FIG. 23 are omitted.
[0380] [0380] Referring to FIG. 24, in the stacked light-emitting structure, according to an exemplary embodiment, the third epitaxial cell 40 can be provided on the substrate 10 and the second adhesive layer 63 can be provided on the third epitaxial cell 40 through the second epitaxial cell 30, interposed between them, and the first epitaxial cell 20 can be provided in the second epitaxial cell 30 through the first adhesive layer 61 interposed between them.
[0381] [0381] The first and second adhesive layers 61 and 63 can include a non-conductive material and an optically transmissive material. For example, an optically clear adhesive can be used for the first and second adhesive layers 61 and 63. The material for forming the first and second adhesive layers 61 and 63 is not particularly limited, as long as it is optically transparent and capable of fixing each epitaxial cell in a stable manner.
[0382] [0382] The third epitaxial cell 40 includes the semiconductor layer type n 41, the active layer 43 and the semiconductor layer type p 45, which are arranged sequentially from the bottom to the top. The type n semiconductor layer 41, the active layer 43 and the type p semiconductor layer 45 of the third epitaxial cell 40 may include a semiconductor material that emits blue light. However, the inventive concepts are not limited to these, and the third epitaxial cell 40 can emit a color of light other than blue. A third p 45p contact electrode is provided above the p 45 semiconductor layer of the third epitaxial cell 40.
[0383] [0383] The second epitaxial cell 30 includes the semiconductor layer type p 35, the active layer 33 and the semiconductor layer type n 31, which are arranged sequentially from bottom to top. The type p semiconductor layer 35, the active layer 33 and the type n semiconductor layer 31 of the second epitaxial cell 30 may include a semiconductor material that emits green light. However, the inventive concepts are not limited to these, and the second epitaxial cell 30 can emit a color of light other than green. A second p 35p contact electrode is provided under the p 35 semiconductor layer of the second epitaxial cell 30.
[0384] [0384] The first epitaxial cell 20 includes the n-type semiconductor layer 21, the active layer 23 and the p-type semiconductor layer 25, which are arranged sequentially from the bottom to the top. The type n semiconductor layer 21, the active layer 23 and the p-type semiconductor layer 25 of the first epitaxial cell 20 may include a semiconductor material that emits red light. However, the inventive concepts are not limited to these, and the first epitaxial cell 20 can emit a color of light other than red. A first p 25p contact electrode is provided above the p 25 semiconductor layer of the first epitaxial cell 20.
[0385] [0385] In an exemplary mode, common lines can be connected to third contact electrodes of type p 45p, to the second contact electrode of type p 35p and to the first contact electrodes of type p 25p. The common line can be a line to which the common voltage is applied. In addition, the light emitting signal lines can be connected to the type 21 semiconductor layers 21, 31 and 41 of the first to third epitaxial cells 20, 30 and 40, respectively. In the exemplary mode, a common voltage SC is applied to the first to the third contact electrodes of type p 25p, 35p and 45p through the common line, and the light emitting signal is applied to semiconductor layers of type n 21, 31, and 41 from the first to the third epitaxial cells 20, 30 and 40 through the light emitting signal lines, thus controlling the light emission from the first to the third epitaxial cells 20, 30 and 40. In this case, the light emitting signal includes the first to the third light emitting signal SR, SG and SB, corresponding to the first to third epitaxial cells 20, 30 and 40, respectively. In an exemplary embodiment, the first light emitting signal SR can be a signal corresponding to red light, the second light emitting signal SG can be a signal corresponding to green light and the third light emitting signal SB can be a signal corresponding to a blue light emission.
[0386] [0386] According to the exemplary modality, the first to third epitaxial cells 20, 30 and 40 are activated, according to a light emitting signal applied to each of the epitaxial cells.
[0387] [0387] In the exemplary embodiment described above, a common voltage is described as being applied to semiconductor layers of type p 25, 35 and 45 of the first to third epitaxial cells 20, 30 and 40, and the light emitting signal is described as being applied to type n semiconductor layers 21, 31 and 41 of the first to third epitaxial cells 20, 30 and 40, however, the inventive concepts are not limited to these.
[0388] [0388] The stacked light-emitting structure, according to an exemplary embodiment, may be able to implement a color so that portions of different colored light are provided in the overlapping region, rather than implementing different colored light in different planes, apart each other's. Therefore, the stacked light-emitting structure, according to an exemplary embodiment, can advantageously provide compactness and integration of the light-emitting element. In addition, according to an exemplary embodiment, since only a stacked light-emitting structure, instead of a plurality of light-emitting elements, is mounted on the stacked light-emitting structure, the manufacturing method is significantly simplified.
[0389] [0389] The stacked light-emitting structure can be a light-emitting element capable of expressing various colors and, therefore, can be employed as a pixel in a display device. In the following, a stacked light-emitting structure will be described that can be used as a pixel in a display device.
[0390] [0390] FIG. 25 is a plan view of a stacked light-emitting structure, according to an exemplary embodiment, and FIG. 26 is a cross-sectional view taken along line III-III 'of FIG. 25.
[0391] [0391] Referring to FIGS. 25 and 26, a stacked light-emitting structure, according to an exemplary embodiment, includes a light-emitting region in which a plurality of epitaxial cells are stacked and a peripheral region surrounding the light-emitting region. The plurality of epitaxial cells includes the first to third epitaxial cells 20, 30 and 40.
[0392] [0392] At least one side of the light-emitting region is provided with a contact to connect the wiring piece to the first and third epitaxial cells 20, 30 and 40. The contact includes a first common contact 50C to apply a voltage common to the first to the third epitaxial cell 20, 30 and 40, a first contact 20C to provide a light emitting signal for the first epitaxial cell 20, a second contact 30C to provide a light emitting signal to the second epitaxial cell 30 and a third contact 40C to provide a light-emitting signal for the third epitaxial cell 40.
[0393] [0393] In an exemplary embodiment, when the stacked light-emitting structure has a substantially square shape in a flat view, the common contact 50C and the first to third contacts 20C, 30C and 40C can be arranged in regions corresponding to the respective corners of the square. However, the positions of the common contact 50C and from the first to the third contacts 20C, 30C and 40C are not limited to them and several modifications are applicable, according to the shape of the stacked light-emitting structure.
[0394] [0394] The first contact 20C is provided with a first pad 20p electrically connected to the first epitaxial cell 20 through the first contact electrode of type n 21n. The second contact 30C is provided with a second pad 30p electrically connected to the type n semiconductor layer of the second epitaxial cell 30. The third contact 40C is provided with a third pad 40p electrically connected to the type n semiconductor layer of the third epitaxial cell 40.
[0395] [0395] The 50C common contact is supplied with a 50P common pad. The common pad 50P is electrically connected to the first to third epitaxial cells 20, 30 and 40 through the first to third contact electrodes of the type p 25p, 35p and 45p, respectively.
[0396] [0396] The common contact 50C is provided with an ohmic electrode 25p 'in a position superimposed on the first contact electrode of type p 25p. The ohmic electrode 25p 'is provided to electrically connect the p-type semiconductor layer of the first epitaxial cell 20 and the first p-type 25p contact electrode, and can be supplied in various positions in various ways. For example, while the ohmic electrode 25p 'is provided in the common contact 50C, the inventive concepts are not limited to these, and the ohmic electrode 25p' can be provided in the light-emitting region.
[0397] [0397] The ohmic electrode 25p 'can be substantially thread-shaped. The ohmic electrode 25p 'is provided for ohmic contact and can include various materials. In an exemplary embodiment, the ohmic electrode 25p 'corresponding to the ohmic electrode of type p may include an Au / Zn alloy or an Au / Be alloy. In this case, since the material of the ohmic electrode 25p 'is lower in reflectivity than Ag, Al, Au or the like, additional reflective electrodes can be further arranged. As an additional reflective electrode, Ag, Au or the like can be used, and Ti, Ni, Cr, Ta or the like can be arranged as a metallic adhesive layer for adhesion to the adjacent components. In that case, the metal adhesive layer can be deposited finely on the upper and lower surfaces of the reflector electrode, including Ag, Au or the like.
[0398] [0398] An adhesive layer, a contact electrode, a wavelength pass filter or the like are provided between substrate 10 and the first to third epitaxial cells 20, 30 and 40, respectively.
[0399] [0399] Referring to FIG. 26, the third to first epitaxial cells 40, 30 and 20 are provided sequentially on substrate 10.
[0400] [0400] The third p 45p contact electrode is provided on the third epitaxial cell 40. Specifically, the third p 45p contact electrode is provided, which contacts the p type semiconductor layer of the third epitaxial cell 40. The third contact electrode type p 45p can include a transparent conductive material, such as transparent conductive oxide (TCO), for example.
[0401] [0401] In an exemplary embodiment, a second filter of passage wavelength 73 can be provided on the third contact electrode of type p 45p. The second wavelength filter 73 is configured to provide high purity, high efficiency colored light, and can be selectively employed in the stacked light-emitting structure. The second wavelength pass filter 73 is configured to block light with a relatively short wavelength from traveling towards the epitaxial cell that emits light with a longer wavelength.
[0402] [0402] In an exemplary embodiment, the second wavelength filter 73 can transmit the second colored light emitted by the second epitaxial cells 30, while blocking or reflecting light other than the second colored light. Therefore, the second colored light emitted from the second epitaxial cell 30 can travel in a direction from the upper to the lower sides, while the third light emitted by the third epitaxial cell 40 is prevented from traveling towards the second epitaxial cell 30 and is reflected or blocked by the second wavelength pass filter 73.
[0403] [0403] The second epitaxial cell 30 is provided in the third epitaxial cell 40 formed with the third contact electrode of the type p 45p, through the second adhesive layer 63 interposed between them.
[0404] [0404] The second p 35p contact electrode is provided under the second epitaxial cell 30, that is, between the second epitaxial cell 30 and the second adhesive layer 63.
[0405] [0405] The first wavelength pass filter 71 can be provided in the second epitaxial cell 30. The first wavelength pass filter 71 is configured to prevent light with relatively short wavelengths from traveling towards the stack. epitaxial that emits light with longer wavelengths and, as will be described below, the first wavelength pass filter 71 can transmit a first colored light emitted by the first epitaxial cell 20, while blocking or reflecting light different from the first colored light . Therefore, the second colored light emitted from the first epitaxial cell 20 can travel in a direction from the upper to the lower sides, while the second colored light emitted from the second epitaxial cell 30 is prevented from traveling towards the first epitaxial cell 20 and is reflected or blocked by the first wavelength pass filter 71.
[0406] [0406] The first epitaxial cell 20 is provided in the second epitaxial cell 30 formed with the second contact electrode of the type p 35p, through the second adhesive layer 63 interposed between them.
[0407] [0407] Portions of the n-type semiconductor layer, the active layer and the p-type semiconductor layer are removed, thus forming a table in the first epitaxial cell 20. The non-table region where the table is not formed is removed when a portion of the semiconductor layer (specifically, portion of the n-type semiconductor layer is removed), which may expose the upper surface of the n-type semiconductor layer. The table region generally overlaps the light-emitting region and the non-table region can overlap the surrounding region in general, and it particularly overlaps the contact.
[0408] [0408] The first n 21n contact electrode is provided on the upper surface of the exposed n type semiconductor layer. The first p 25p contact electrode is supplied above the p type semiconductor layer that has the table, via the ohmic electrode 25p 'and the first optically non-transmissive film 83 interposed between them.
[0409] [0409] The first optically non-transmissive film 83 covers the upper surface of the first epitaxial cell 20 and has a contact orifice in a portion provided with the ohmic 25p 'electrode. The ohmic electrode 25p 'is provided to correspond to the region where the common contact 50C is provided, and can be provided in various forms, for example, substantially a threaded shape.
[0410] [0410] The first p 25p contact electrode is provided in the first optically non-transmissive film 83. When viewed from the flat view, the first p 25p contact electrode can be supplied in a way that the first contact electrode of the type p 25p overlaps the light-emitting region, while covering the entire light-emitting region. The first p 25p type contact electrode may include a reflective material to reflect the light from the first epitaxial cell 20 in a lower direction. Various reflective metals can be used as a reflective material to form the first p 25p contact electrode, such as Ag, Al, Au or similar. If necessary, Ti, Ni, Cr, Ta or others can be arranged as an adhesive layer for adhesion to adjacent components.
[0411] [0411] According to an exemplary modality, the first p 25p type contact electrode can be selected from a material with high reflectivity in the red light wavelength range of the first epitaxial cell
[0412] [0412] The first optically non-transmissive film 83 can also be formed to have a reflective property to facilitate the reflection of light from the first epitaxial cell
[0413] [0413] A second optically non-transmissive film 85 is provided in the first optically non-transmissive film 83, where the first p 25p type contact electrode is provided. The second optically non-transmissive film 85 covers the upper surface of the first epitaxial cell 20 and the sides of each component under the second optically non-transmissive film
[0414] [0414] The first to third pads 20P, 30P and 40P and the common pad 50P are provided on the second optically non-transmissive film 85. The first to third pads 20P, 30P and 40P and the common pad 50P can be connected to the first to third pads scan lines and data lines, respectively.
[0415] [0415] The first to third pads 20P, 30P and 40P and the common pad 50P can be formed of single layer or multilayer metals. For example, the first to third pads 20P, 30P and 40P and the common pad 50P can be formed from various materials, such as Al, Ti, Cr, Ni, Au, Ag, Ti, Sn, Ni, Cr, W, Cu, or others, or their alloys.
[0416] [0416] Each of the first to third pads 20P, 30P and 40P and the common pad 50P are connected to the corresponding corresponding components through the holes provided below, as the first to the fourth contact holes CH1, CH2, CH3 and CH4 and one first contact hole CH1 '.
[0417] [0417] The common pad 50P is connected to the first contact electrode of type p 25p through the first contact hole CH1 'and connected to the second and third contacts of type p 35p and 45p through the first contact hole CH1. The first pad 20P is connected to the n-type semiconductor layer of the first epitaxial cell 20 through the second contact hole CH2. The second pad 30P is connected to the n-type semiconductor layer of the second epitaxial cell 30 through the third contact hole CH3. The third pad 40P is connected to the n-type semiconductor layer of the second epitaxial cell 30 through the fourth contact hole CH4.
[0418] [0418] The stacked light-emitting structure described above can emit light in the lower direction, emitting light from the first to the third epitaxial cells 20, 30 and 40. The first to the third pads 20P, 30P and 40P and the common pad 50P can be connected , each of the first to third scan lines and data lines and, consequently, separate direction signals can be applied to the first and third epitaxial cells 20, 30 and 40 through the first to third pads 20P, 30P and 40P, and a common voltage can be applied via the 50P common pad. In this way, the light emission from the first to the third epitaxial cells 20, 30 and 40 can be controlled independently.
[0419] [0419] FIGS. 27, 29, 31 and 33 are plan views illustrating a method of making an epitaxial cell, according to an exemplary embodiment, and FIGS. 28, 30A and 30B, 32A and 32B and 34 are sectional views taken along line III-III 'in FIGS. 27, 29, 31 and 33, respectively, according to exemplary modalities.
[0420] [0420] Referring to FIGS. 27 and 28, a stacked light-emitting structure, according to an exemplary embodiment, has a third epitaxial cell 40 formed on the substrate 10. The third contact electrode of type p 45p and the second wavelength filter 73 are formed in the third epitaxial cell 40.
[0421] [0421] Then, the second epitaxial cell 30 is formed on a fourth temporary substrate. The fourth temporary substrate can be a semiconductor substrate on which the second epitaxial cell 30 can be formed on it. The fourth temporary substrate can be defined differently depending on the desired semiconductor layer to be formed. The second epitaxial cell 30 can be manufactured by forming the n-type semiconductor layer, the active layer and the p-type semiconductor layer on the fourth temporary substrate. The second p 35p contact electrode is formed on the upper surface of the second epitaxial cell 30.
[0422] [0422] The second epitaxial cell 30 formed on the fourth temporary substrate is inverted and then adhered to the third epitaxial cell 40 formed with the second adhesive layer 63 and then the fourth temporary substrate is removed. The fourth temporary substrate can be removed by various methods, such as wet etching, dry etching, physical removal, laser removal or the like.
[0423] [0423] Next, the first epitaxial cell 20 is formed on the second epitaxial cell 30. The first epitaxial cell 20 can be formed on a fifth temporary substrate and the fifth temporary substrate can be a semiconductor substrate on which the second epitaxial cell 30 can be formed. be formed. The fifth temporary substrate can be defined differently, depending on the desired semiconductor layer to be formed. The first epitaxial cell 20 is manufactured by forming the n-type semiconductor layer, the active layer and the p-type semiconductor layer on the fifth temporary substrate.
[0424] [0424] The first epitaxial cell 20 formed on the fifth temporary substrate is inverted and then adhered to the second epitaxial cell 30 formed with the first adhesive layer 61 and then the fifth temporary substrate is removed. The fifth temporary substrate can be removed by various methods, such as wet etching, dry etching, physical removal, laser removal or the like.
[0425] [0425] Next, the active layer of the first epitaxial cell 20, a portion of the p-type semiconductor layer and, if necessary, a portion of the n-type semiconductor layer are removed to form a table structure. Formation of the table structure allows the upper surface of the n-type semiconductor layer of the first epitaxial cell 20 to be exposed.
[0426] [0426] The first n 21n contact electrode is formed on the exposed upper surface of the n type semiconductor layer and a first optically non-transmissive film 83 is formed on the first n 21n contact electrode. The contact orifice is provided in the first optically non-transmissive film 83 to expose a portion of the upper surface of the first epitaxial cell 20, and the ohmic electrode 25p 'is formed in the contact orifice.
[0427] [0427] In an exemplary embodiment, a component such as the table structure is described as being formed in the first epitaxial cell 20, in the first contact electrode of type n 21n, in the ohmic electrode 25p 'or similar after the transfer of the first epitaxial cell 20 for the second epitaxial cell 30, but the inventive concepts are not limited to these. According to an exemplary embodiment, the first contact electrode of type n 21n, the ohmic electrode 25p 'or the like can be formed for the first time in the first epitaxial cell 20 on the first temporary substrate or using a separate additional temporary substrate and then transferring the first standardized epitaxial cell 20 to the second epitaxial cell 30.
[0428] [0428] Referring to FIGS. 29, 30A and 30B, the first p 25p contact electrode is formed in the first epitaxial cell 20 which is formed with the first optically non-transmissive film 83, or the like. The first p 25p type contact electrode can include a reflective material and is formed to cover the light-emitting region. The first p 25p contact electrode can be formed by forming a reflective conductive material on the front side and then standardizing it using photolithography, or the like.
[0429] [0429] After the formation of the first p 25p type contact electrode, the portions of the first epitaxial cell 20, the first adhesive layer 61 and the first wavelength pass filter 71 are removed in the regions corresponding to the light-emitting region other than the light emitting region, the common contact 50C, the second contact 30C and the third contact 40C, resulting in the formation of the first to fourth contact holes CH1, CH2, CH3 and CH4. As such, the upper surface of the n-type semiconductor layer of the second epitaxial cell 30 is exposed at the second contact 30C.
[0430] [0430] In this case, the first epitaxial cell 20, the first adhesive layer 61 and the first wavelength pass filter 71 can be standardized by dry recording or wet recording using photolithography. The sides of the first epitaxial cell 20, the first adhesive layer 61 and the first wavelength pass filter 71 are obliquely patterned with respect to a substrate surface 10. Specifically, the angle formed between the first epitaxial cell 20 and a side of the substrate can be between about 45 degrees and about 85 degrees.
[0431] [0431] Referring to FIGS. 31, 32A and 32B, in the first contact hole CH1 of the common contact 50C, which is one of the regions corresponding to the light-emitting region other than the light-emitting region, the common contact 50C, the second contact 30C, the third contact 40C, and a portion of the upper surface of the second epitaxial cell 30 is removed, thereby exposing a portion of the upper surface of the second p-type 35p contact electrode. In this case, the side of the second epitaxial cell 30 is obliquely patterned with respect to the upper surface of the substrate 10, and the angle formed between the second epitaxial cell 30 and the upper surface of the substrate 10 can be between about 45 degrees and about 85 degrees.
[0432] [0432] Then, the portions of the second p 35p type contact electrode, the second adhesive layer 63 and the second wavelength pass filter 73 are additionally removed,
[0433] [0433] The sides of the third epitaxial cell 40, the second adhesive layer 63, the second wavelength pass filter 73 and the third type p 45p contact electrode are obliquely standardized in relation to the top surface of the substrate 10. Specifically , the angle formed between the third epitaxial cell 40 and the upper side of the substrate 10 can be between about 45 degrees and about 85 degrees.
[0434] [0434] Next, the second optically non-transmissive film 85 is formed on the substrate 10 which is formed with the contact holes, or the like. Since the other components, including the first to third epitaxial cells 20, 30 and 40, are angled, the second optically non-transmissive film 85 can be formed with sufficient thickness along the inclined sides. In general, it may be difficult to form the second optically non-transmissive film 85 with sufficient thickness if the other components including the first to the third epitaxial cells 20, 30 and 40 have vertical or almost vertical sides. The second optically non-transmissive film 85 may also be a DBR or an organic polymer film with a black color. In an exemplary embodiment, a floating metal reflective film can also be provided in the first optically non-transmissive film 83. In an exemplary embodiment, the optically non-transmissive film can be formed by depositing two or more insulation films with different refractive indexes than one other.
[0435] [0435] The second optically non-transmissive film 85 is formed on the front of the substrate 10 and then standardized to expose the underlying components in some regions. Therefore, the second optically non-transmissive film 85 has the first "CH1 contact hole" partially exposing the top surface of the first type 25p contact electrode in common contact 50C, the first CH1 contact hole exposing the upper surfaces of the second and third type n contact electrodes, the second contact hole CH2 exposing the upper surface of the first type n contact electrode 21n in the first contact 20C, the third contact hole CH3 exposing the upper surface of the type n semiconductor layer of the second epitaxial cell 30 at the second contact 30C and fourth contact hole CH4 exposing the upper surface of the type n semiconductor layer of the third epitaxial cell 40 at the third contact 40C.
[0436] [0436] Referring to FIGS. 33 and 34, the common pad 50P and the first to third pads 20P, 30, P and 40P are then formed in the common contact 50C formed with the first to fourth contact holes CH1, CH2, CH3 and CH4 and the first to the third contacts 20C, 30C and 40C.
[0437] [0437] According to an exemplary embodiment, irregularities can be selectively provided on the lower surfaces of the first to third epitaxial cells 20, 30 and 40. Each of the irregularities can be provided only in a portion corresponding to the light-emitting region.
[0438] [0438] In addition, according to an exemplary embodiment, an additional optically non-transmissive film can still be supplied on the side of the stacked light-emitting structure.
[0439] [0439] By providing the optically non-transmissive film on the sides of the stacked light-emitting structure, it is possible to prevent the phenomenon in which the light emitted by a certain stacked light-emitting structure affects the adjacent stacked-light-emitting structures or the phenomenon in that the color is mixed with the light emitted by the adjacent stacked light-emitting structures.
[0440] [0440] As described above, since the common voltage and the light emitting signal are applied to the common contact 50C and the first to the third contact 20C, 30C and 40C, respectively, whether or not to emit the light in the first to the third epitaxial cells 20, 30 and 40 can be controlled independently and, as a result, various colors can be implemented using the light emission of each of the epitaxial cells.
[0441] [0441] FIG. 35 is a schematic plan view of a display apparatus according to an exemplary embodiment. FIG. 36 is a schematic cross-sectional view of an LED pixel for a display, according to an exemplary embodiment.
[0442] [0442] Referring to FIGS. 35 and 36, the display apparatus 201 includes a circuit board 251 and a plurality of pixels
[0443] [0443] Circuit board 251 can have either a passive circuit or an active circuit. For example, the passive circuit can include data lines and scan lines. For example, the active circuit can include a transistor and / or a capacitor. Circuit board 251 may have a circuit located on or on a surface. Circuit board 251 can include, for example, a glass substrate, a sapphire substrate, a Si substrate or a Ge substrate.
[0444] [0444] Substrate 221 can support the first to third subpixel R, G and B. When substrate 221 is omitted, the first to third subpixels R, G and B can be supported by circuit board 251. Substrate 221 can be formed continuously over the plurality of pixels 200 and electrically connect the first to the third subpixel R, G and B to the circuit board 251. The substrate 221 can be, for example, a GaAs substrate, but is not limited to it.
[0445] [0445] The first subpixel R includes the first LED battery 223, the second subpixel G includes the second LED battery 233 and the third subpixel B includes the third LED battery 243. The first subpixel R is configured so that light is emitted from the first LED stack 223, the second subpixel G is configured so that light is emitted from the second LED stack 233 and the third subpixel B is configured so that light is emitted from the third LED stack 243. The first to third LED batteries 223, 233 and 243 can be activated independently of each other.
[0446] [0446] The first LED stack 223, the second LED stack 233 and the third LED stack 243 are stacked in a vertical direction to overlap. The second 233 LED stack can be arranged in a partial region of the first 223 LED stack. The second 233 LED stack can be arranged in the side direction on the first 223 LED stack. The third 243 LED stack can be arranged in a side direction. a partial region of the second 233 LED battery. The third 243 LED battery can be arranged towards one side on the second 233 LED battery. However, the inventive concepts are not limited to these and the third LED battery may be towards the left side of the second 233 LED stack.
[0447] [0447] The R light generated in the first LED battery 223 can be emitted from a region that is not covered by the second LED battery 233 and the G light generated in the second LED battery 233 can be emitted from a region which is not covered by the third LED battery 243. In particular, the light generated from the first LED battery 223 can be emitted to the outside without going through the second LED battery 233 and the third LED battery 243, and the light generated in the second battery of LED 233 can be emitted to the outside without passing through the third battery of LED 243.
[0448] [0448] In addition, an area of a region from which R light is emitted from the first LED stack 223, an area of a region from which G light is emitted from the second LED stack 233 and an area of a region of the third LED stack 243 can be different from each other and an intensity of light emitted from each of the first to the third LED stack 223, 233 and 243 can be adjusted by adjusting these areas.
[0449] [0449] However, inventive concepts are not limited to these. The light generated in the first LED battery 223 can pass through the second LED battery 233 or pass through the second LED battery 233 and the third LED battery 243 and emitted to the outside. The light generated in the second LED battery 233 can pass through the third LED battery 243 and emitted to the outside.
[0450] [0450] Each of the first LED stack 223, the second LED stack 233 and the third LED stack 243 includes a first conductivity-type semiconductor layer (for example, an n-type semiconductor layer), a second semiconductor layer conductivity type (for example, a p-type semiconductor layer) and an active layer interposed between them. The active layer may, in particular, have a multi-quantum well structure. The first to third LED batteries 223, 233 and 243 can include different active layers and therefore can emit light of different wavelengths. For example, the first battery of LED 223 can be an inorganic LED that emits red light, the second battery of LED 233 can be an inorganic LED that emits green light and the third battery of LED 243 can be an inorganic LED that emits blue light . For this purpose, the first stack of LED 223 may include a well layer based on AlGaInP, the second stack of LED 233 may include a well layer based on AlGaInP or based on AlGaInN and the third stack of LED 243 may include a layer well based on AlGaInN. However, the inventive concepts are not limited to these, and an order of the light emitted from the first LED battery 223, the second LED battery 233 and the third LED battery 243 can be modified. For example, the first battery of LED 223 can emit any of the red, green and blue lights, and the second battery of LED 233 and the third battery of LED 243 can, respectively, emit a different one from the red, green and blue light of each other.
[0451] [0451] In addition, a distributed Bragg reflector can be disposed between substrate 221 and the first LED stack 223 to prevent the light generated in the first LED stack 223 from being absorbed by the substrate 221 and lost. For example, a distributed Bragg reflector formed by the alternate stacking of an AlAs-based semiconductor layer and an AlGaAs-based semiconductor layer.
[0452] [0452] The third LED stack 243 and the second LED stack 233 can have sloping side surfaces. Angled side surfaces can improve the reliability of a display device by increasing the coverage of an insulation layer or interconnect line, such as a connector, formed on the side surface of the 233 and 243 LED cells. The first LED cell 223 can also have an inclined side surface. As used herein, a connector can be any type of structure, including through holes, pathways, wires, lines, conductive material and the like, which serve to connect two elements, electrically and / or mechanically, as layers.
[0453] [0453] FIGS. 37A 37B are schematic circuit diagrams of a display device, according to exemplary modalities.
[0454] [0454] Referring to FIG. 37A, the display apparatus, according to an exemplary embodiment, can be operated in an active matrix manner. For this purpose, a circuit board may include an active circuit.
[0455] [0455] For example, a drive circuit, according to an exemplary mode, can include two or more transistors, for example, Tr1 and Tr2, and a capacitor. When a power source is connected to the selection lines Vrow1 to Vrow3, and when the voltage is applied to the data lines Vdata1 to Vdata3, the voltage can be applied to the corresponding LED. In addition, a corresponding capacitor can be charged with electrical charges based on the values of data lines Vdata1 to Vdata3. A state in which transistor Tr2 is connected can be maintained by the charged voltage of the capacitor and therefore the capacitor voltage can be maintained and applied to LEDs LED1 to LED3, even if a power supply for the Vrow1 line is cut. In addition, the current flowing from LEDs LED1 to LED3 can be changed based on the values of data lines Vdata1 to Vdata3. The current can be supplied through the Vdd all the time and, therefore, it is possible to continue emitting light.
[0456] [0456] Transistors Tr1 and Tr2 and capacitor can be formed on a circuit board 251. Here, LEDS LED1 to LED3 can correspond to the first to third batteries of LEDs 223, 233, and 243 stacked in a single pixel, respectively. The anodes of the first to the third LED batteries 223, 233 and 243 are connected to the transistors Tr2 and their cathodes can be grounded. As shown in Fig. 37A, the cathodes from the first to the third stack of LEDs 223, 233 and 243 can be commonly connected in common and grounded.
[0457] [0457] FIG. 37A show a circuit diagram to drive an active matrix, however, the inventive concepts are not limited to these and another circuit can be used. Furthermore, although the anodes of LEDs LED1 to LED3 are described as connected to different transistors (for example, transistors Tr2) and their cathodes are described as grounded, according to some exemplary modalities, the anodes of the first to the third batteries LEDs 223, 233 and 243 can be connected in common and the cathodes can be connected to different transistors.
[0458] [0458] FIG. 37B is a schematic circuit diagram for passive matrix conduction.
[0459] [0459] Circuit board 251 can include data lines,
[0460] [0460] According to an exemplary modality, each of the first to third LED batteries 223, 233 and 243 can be activated using a pulse width modulation method or by changing a current intensity, so that a brightness from each subpixel can be adjusted. In addition, the brightness can be adjusted by changing an area from each of the first to the third LED batteries 223, 233 and 243, and an area of a region from which the R, G and B lights are emitted in each of the first to third LED batteries 223, 233 and 243. For example, an area of one LED battery, for example, the first LED battery 223, which emits light with low visibility may be larger than an area of the second LED battery 233 or an area of the third LED stack 243, in order to emit light with greater intensity under the same current density. In addition, since the area of the second LED battery 233 is larger than the area of the third LED battery 243, the second LED battery 233 can emit light with a higher density than the third LED battery 3430 under the same current density. As such, a light output can be controlled by considering the visibility of the light emitted from the first LED battery 223, the second LED battery 233 and the third LED battery 243 by adjusting an area of each of the first to the third battery cells. LED 223, 233 and 243.
[0461] [0461] FIGS. 38A and 38B are an enlarged plan view and an enlarged bottom view of a pixel region of a display apparatus, according to exemplary embodiments, respectively. FIGS. 39A, 39A, 39C, and 39D are schematic cross-sectional views taken along lines A-A, B-B, C-C and D-D of FIG. 38A, respectively.
[0462] [0462] A pixel of a display device is arranged on a circuit board (for example, circuit board 251 of FIG. 35) and each substrate 221, and the first to the third subpixels R, G and B. O substrate 221 can be continuous across the plurality of pixels. In the following, a single pixel will be described in more detail.
[0463] [0463] Referring to FIGS. 38A, 38B, 39A, 39B, 39C, and 39D, a pixel can include a substrate 221, a distribution Bragg reflector 222, an insulation layer 225, passageways 227a, 227b, and 227c, a first LED stack 223 , a second battery of LED 233, a third battery of LED 243, a first ohmic electrode 1 229a, a first ohmic electrode 2 229b, a second ohmic electrode 1 239, a second ohmic electrode 2 235, a third ohmic electrode 1 249, a third ohmic electrode 2 245, a first connection layer 253, a second connection layer 255, an upper insulation layer 261, connectors 271, 272, and 273, a lower insulation layer 275, and electrode pads 277a, 277b , 277c, and 277d.
[0464] [0464] The first to the third subpixels R, G and B can include 223, 233 and 243 LED batteries and ohmic electrodes,
[0465] [0465] Substrate 221 supports the first to third LED cells 223, 233 and 243. Substrate 221 can be a growth substrate capable of growing semiconductor layers based on AlGaInP and can include, for example, a GaAs substrate. In particular, substrate 221 can be a semiconductor substrate and can exhibit n-type conductivity.
[0466] [0466] The first LED stack 223 includes a first semiconductor layer of conductivity type 223a and the second semiconductor layer of conductivity type 233b, and the second LED stack 233 includes a first semiconductor layer of conductivity type 233a and a second semiconductor layer of conductivity type 233b. The third LED stack 243 includes a first conductivity-type semiconductor layer 243a and a second conductivity-type semiconductor layer 243b. An active layer can be interposed in each of the first semiconductor layers of conductivity type 223a, 233a or 243a and each of the second semiconductor layers of conductivity type 223b, 233b or 243b.
[0467] [0467] According to an exemplary embodiment, each of the first semiconductor layers of conductivity type 223a, 233a, and 243a can be a semiconductor layer of type n and each of the semiconductor layers of conductivity type 223b, 233b, 243b can be a p-type semiconductor layer. A rough surface by surface texturing (or irregularities) can be formed on an upper surface of each of the first semiconductor layers of conductivity type 223a, 233a, and 243a. However, the inventive concepts are not limited to them, and the types of semiconductors in the first conductivity semiconductor layer and the second conductivity semiconductor layer can be reversed.
[0468] [0468] The first 223 LED stack is located near circuit board 251, the second 233 LED stack is located on the first 223 LED stack and the third 243 LED stack is located on the second 233 LED stack. The second LED stack 233 is arranged in a partial region of the first LED stack 223 so that the first LED stack 223 partially overlaps the second LED stack 233. The third LED stack 243 is arranged in a partial region of the second stack LED 233 so that the second LED 233 battery partially overlaps the third LED 243 battery. Thus, the light generated in the first LED 223 battery can be emitted to the outside without going through the second and third LED 233 batteries and
[0469] [0469] The materials of the first LED battery 223, the second LED battery 233 and the third LED battery 243 are substantially the same as those described with reference to FIG. 36 and therefore duplicate descriptions will be omitted to avoid redundancy.
[0470] [0470] The first 223 LED battery has an inclined side surface. As used herein, the "inclined side surface" can refer to a surface that is not perpendicular to an upper surface or to a lower surface of the first LED stack 223 and, in particular, that forms an angle of inclination between a lateral surface and the bottom surface of the first 223 LED stack less than about 90 degrees. The second LED stack 233 and the third LED stack 243 can also include angled side surfaces. In particular, a side surface of the second LED stack 233 can have an angle of inclination less than 90 degrees with respect to a bottom surface of the second LED stack 233 and a side surface of the third LED stack 243 can also have an angle of inclination less than 90 degrees in relation to a lower surface of the third LED stack 243.
[0471] [0471] Although FIG. 39A show that all first to third LED batteries 223, 233 and 243 have inclined side surfaces, however, the inventive concepts are not limited to these. For example, at least one of the first to third LED batteries 223, 233 and 243 may not have an inclined side surface. In addition, according to some exemplary embodiments, only a portion of the side surface of the first LED stack 223, the second LED stack 233 or the third LED 243 can be tilted.
[0472] [0472] The distributed Bragg reflector 222 is interposed between substrate 221 and the first LED stack 223. The distributed Bragg reflector 222 can be formed with semiconductor layers grown on substrate 221. For example, the distributed Bragg reflector 222 can be formed by alternately stacking a layer of AlAs and a layer of AlGaAs. The distributed Bragg reflector 222 can be semiconductor layers, which electrically connect substrate 221 to the first conductivity-type semiconductor layer 223a of the first LED stack 223. The distributed Bragg reflector 222 can also have an inclined side surface, but is not limited this.
[0473] [0473] Passage ways 227a, 227b and 227c that pass through substrate 221 can be formed. Orifice paths 227a, 227b and 227c can also pass through the first LED stack 223. Orifice paths 227a, 227b, and 227c can be formed of conductive or plating pastes. Although passageways 227a, 227b and 227c are shown to be of constant width, the inventive concepts are not limited to these. The widths of passageways 227a, 227b and 227c can vary along the horizontal or vertical direction. For example, the widths of passageways 227a, 227b and 227c can decrease from top to bottom of substrate 221.
[0474] [0474] Insulation layer 225 is arranged between orifice paths 227a, 227b and 227c and an inner wall of a through hole passing through substrate 3210 and the first stack of LED 223, to prevent through holes 227a , 227b and 227c short-circuit the substrate 221 and the first LED stack 223.
[0475] [0475] The first ohmic electrode 1 229a is in ohmic contact with the first semiconductor layer of conductivity type 223a of the first LED stack 223. The first ohmic electrode 1 229a can be formed, for example, by an Au- Te or an Au-Ge alloy.
[0476] [0476] To form the first ohmic electrode 229a, the second semiconductor layer of conductivity type 223b and the active layer can be partially removed, and the first semiconductor layer of conductivity type 223a can be exposed. The first ohmic electrode 1 229a can be disposed away from the region where the second LED stack 233 is disposed. In addition, the first ohmic electrode 1 229a can include a pad region and an extension, and connector 271 can be connected to the pad region, as shown in FIG. 38A.
[0477] [0477] The first ohmic electrode 2 229b is in ohmic contact with the second semiconductor layer of conductivity type 223b of the first LED stack 223. For current dispersion, the first ohmic electrode 2 229b can be formed to partially surround the first electrode ohmic 1 229a, as shown in FIG. 38A. However, the first ohmic electrode pad 2 229b is not necessarily formed to have an extension. The first ohmic electrode 1 229b can be formed from, for example, an Au-Zn alloy or an Au-Be alloy, or others. In addition, the first ohmic electrode pad 2 229b can be formed as a single layer, but is not limited to this, and can be formed of multiple layers.
[0478] [0478] The first ohmic electrode 2 229b can be connected to the passageway 227a, so that the passageway 227a can be electrically connected to the second semiconductor layer of conductivity type 223b.
[0479] [0479] The second ohmic electrode 1 239 is in ohmic contact with the first semiconductor layer of conductivity type 233a of the second LED stack 233. The second ohmic electrode 1 239 can also include a pad region and an extension. The connector 271 can electrically connect the second ohmic electrode 1 239 to the first ohmic electrode 1 229a, as shown in FIG. 38A. The second ohmic electrode 1 239 can be separated from the region where the third LED battery 243 is located.
[0480] [0480] The second ohmic electrode 2 235 is in ohmic contact with the second semiconductor layer of conductivity type 233b of the second LED stack 233. The second ohmic electrode 2 235 may include a reflective layer 235a and a barrier layer 235b. The reflective layer 235a can reflect the light generated in the second 233 LED stack to improve the luminous efficacy of the second 233 LED stack. The barrier layer 235b can protect the reflective layer 235a and can act as a connection pad to which the connector 272 is connected. The second ohmic electrode 2235 may be formed, for example, by a metal layer, but is not limited to this. For example, the second ohmic electrode 2235 may be formed from a transparent conductive layer such as a conductive oxide semiconductor layer.
[0481] [0481] The third ohmic electrode 1 249 is in ohmic contact with the first semiconductor layer of conductivity type 243a of the third LED stack 243. The third ohmic electrode 1 249 may also include a pad region and an extension. The connector 271 can connect the third ohmic electrode 1 249 to the first ohmic electrode 1 229a, as shown in FIG. 38A.
[0482] [0482] The third ohmic electrode 2 245 is in ohmic contact with the second semiconductor layer of conductivity type 243b of the third LED stack 243. The third ohmic electrode 2 245 may include a reflective layer 245a and a barrier layer 245b. The reflective layer 245a can reflect the light generated in the third LED stack 243 to improve the luminous efficacy of the third LED stack 243. The barrier layer 245b can protect the reflective layer 245a and can function as a connection pad to which the connector 273 is connected. The third ohmic electrode 2 245 may include a reflective layer 245a and a barrier layer 245b. For example, the third ohmic electrode 2 245 can be formed from a transparent conductive layer such as a conductive oxide semiconductor layer.
[0483] [0483] The first ohmic electrode 2 229b, the second ohmic electrode 2 235 and the third ohmic electrode 2 245 can be in ohmic contact with the p-type semiconductor layers of the LED cells, respectively, to aid in current dispersion. The first ohmic electrode 1 229a, the second ohmic electrode 1 239 and the third ohmic electrode 1 249 may be in ohmic contact with the n-type semiconductor layers of each of the LED cells, to aid in current dispersion.
[0484] [0484] The first connection layer 253 couples the second battery of LED 233 to the first battery of LED 223. The second ohmic electrode 2 235 can be in contact with the first connection layer 253. The first connection layer 253 can be transmissive to light or non-transmissive to light. The first bonding layer 253 can be formed by a layer of organic material, or a layer of inorganic material. The organic material layer may include, for example, SU8, poly (methyl methacrylate) (PMMA), polyimide, parylene, benzocyclobutene (BCB) or others, and the inorganic material layer may include, for example, Al2O3, SiO2, SiNx, or others. The layer of organic material can be bonded at high vacuum and high pressure. The layers of inorganic material can be planarized by the surface by, for example, a mechanical chemical polishing process, so the surface energy can be controlled using plasma, or others, and can be connected in high vacuum using the surface energy. The first bonding layer 253 can also be formed by a spin-on glass method and can be formed as a metal bonding layer, such as AuSn. When a metal bonding layer is adopted, an insulating layer for electrical insulation of the first LED stack and the metal bonding layer can be disposed on the first 223 LED stack. In addition, to prevent the light generated in the first LED stack 223 is incident on the second LED stack 233, a reflective layer can be added between the first link layer 253 and the first LED stack 223.
[0485] [0485] The first connection layer 253 can also have an inclined side surface. In particular, the first link layer 253 can have an angle of inclination less than about 90 degrees with respect to the top surface of the first LED stack 223. Although the angle of inclination of the first link layer 253 can be substantially the same as an angle of inclination of the second LED stack 233, the inventive concepts are not limited to these. For example, the angle of inclination of the first link layer 253 may differ from the angle of inclination of the second LED stack 233. In an exemplary embodiment, the angle of inclination of the second LED stack 233 may be greater than the angle of inclination. of the first connection layer 253 and, consequently, it is possible to improve a step cover of the connectors 271, 272 and 273 or the insulation layer 261 formed on a side surface of the second LED stack 233 and / or on a side surface of the first link layer 253. In another exemplary embodiment, the angle of inclination of the second LED stack 233 may be less than the angle of inclination of the first link layer 253 and, consequently, it is possible to increase a light emission area of the second stack 233 LED.
[0486] [0486] The second connection layer 255 couples the second battery of LED 233 and the third battery of LED 243. The second connection layer 255 can be arranged between the second battery of LED 233 and the third ohmic electrode 2 245, can connect the second LED stack 233 to the third ohmic electrode 2 245. The second bonding layer 255 can also be formed of bonding material. In addition, an insulating layer and / or a reflective layer can be added between the second LED stack 233 and the second connection layer 255.
[0487] [0487] The second connection layer 255 can also have an inclined side surface. In particular, the second connection layer 255 may have an angle of inclination less than about 90 degrees with respect to the upper surface of the second LED stack 233. Although the angle of inclination of the second connection layer 255 may be substantially the same as an angle of inclination of the third LED stack 243, the inventive concepts are not limited to these. For example, the inclination angle of the second connection layer 255 may be different from the inclination angle of the third LED stack 243. In an exemplary embodiment, the inclination angle of the third LED stack 243 may be greater than the inclination angle of the second connection layer 255 and, consequently, it is possible to improve a step covering of the connectors 271 and 273 or of the insulation layer 261 formed on a side surface of the third LED stack 243 and / or on a side surface of the second layer of connection 255. In another exemplary embodiment, the angle of inclination of the third LED stack 243 may be less than the angle of inclination of the second connection layer 255 and, consequently, it is possible to increase a light emission area of the third LED stack 243.
[0488] [0488] When the first bonding layer 253 and the second bonding layer 255 are formed of a light transmitting material, and when the second ohmic electrode 2 235 and the third ohmic electrode 2 245 are formed of a transparent oxide material, a portion of the light generated in the first LED stack 223 can pass through the first link layer 253 and the second ohmic electrode 2 235 and can be incident on the second LED stack 233 and can be emitted to the outside via the second LED stack 233. In addition, a portion of light generated in the first LED battery 223 can pass through the second connection layer 255 and the third ohmic electrode 2 245, can be incident on the third LED battery 243 and then be emitted to the outside. In addition, a portion of the light generated in the second LED battery 233 can pass through the second connection layer 255 and the third ohmic electrode 245, can fall on the third LED battery 243 and then be emitted to the outside.
[0489] [0489] In this case, there is a need to prevent the light generated in the first LED stack 223 from being absorbed by the second LED stack 233 while the light passing through the second LED stack 233. To that end, the light generated in the first LED stack 223 may need to have an energy less than a gap energy of the second LED stack 233 and, therefore, a wavelength of the light generated in the first LED stack 223 may be greater than that of light generated in the second LED stack. LED 233.
[0490] [0490] Furthermore, to prevent the light generated from the second LED 233 battery from being absorbed by the third LED 243 battery while the light passes through the third LED 243 battery, the light generated in the second 233 LED battery may have a wavelength greater than the light generated in the third LED stack 243.
[0491] [0491] Meanwhile, when the first link layer 253 and the second link layer 255 are not light transmissive, the reflective layers can be interposed between the first LED stack 223 and the first link layer 253 and between the second LED stack 233 and second link layer 255, respectively, to reflect light generated from the first LED stack 223 and incident on the first link layer 253 and light generated on the second LED stack 233 and incident on the second layer of connection 255. The reflected light can be emitted to the outside through the first battery of LED 223 and the second battery of LED 233, respectively.
[0492] [0492] The top insulation layer 261 can substantially the first to the third LED batteries 223, 233 and
[0493] [0493] The top insulation layer 261 has openings that expose the first to third orifice paths 227a, 227b and 227c and also openings that expose the first semiconductor layer of conductivity type 233a of the second LED stack 223, the first semiconductor layer conductivity type 243a of the third LED battery 243, the second ohmic electrode 2 235 and the third ohmic electrode 2 245.
[0494] [0494] The top insulating layer 261 can be, but is not particularly limited to, a layer of insulating material and can be formed, for example, by silicon oxide or silicon nitride. The upper insulating layer 261 can be formed using a chemical vapor deposition technique, but is not limited to it, and can be formed using a spraying technique. In particular, when an inclination angle of the first link layer 253 (or the second link layer 255) is greater than an inclination angle of the second LED stack 233 (or the third LED stack 243), a step cover can be improved using the spray technique.
[0495] [0495] Connector 271 electrically connects the first ohmic electrode 1 229a, the second ohmic electrode 1 239 and the third ohmic electrode 1 249 to each other. The connector 271 is formed in the upper insulation layer 261 and is isolated from the second semiconductor layer of conductivity type 243b of the third LED stack 243, the second semiconductor layer of conductivity type 233b from the second LED stack 233 and the second semiconductor layer conductivity type 223b of the first 223 LED battery.
[0496] [0496] The connector 271 can be formed substantially of the same material as those of the second ohmic electrode 1 239 and the third ohmic electrode 1 249 and therefore can be formed together with the second ohmic electrode 1 239 and the third ohmic electrode 1 249 However, the inventive concepts are not limited to these and the connector 271 can be formed from a different layer from the second ohmic electrode 1 239 or from the third ohmic electrode 1 249 and therefore can be formed separately by a different process than the second ohmic electrode 1 239 and / or the third ohmic electrode 1 249.
[0497] [0497] As shown in Fig. 39A, connector 271 can be formed on sloping side surfaces of the second and third LED stacks 233 and 243 and the first and second connecting layers 253 and 255. Since the second and third LED batteries 233 and 243 and the first and second connection layers 253 and 255 have slanted side surfaces, the likelihood of disconnection of connector 271 can be reduced or avoided compared to when the second and third LED batteries 233 and 243 and the first and second link layers 253 and 255 have vertical side surfaces and therefore the reliability of a pixel can be improved.
[0498] [0498] Connector 272 can electrically connect the second ohmic electrode 2 235, for example, the barrier layer 235b, and the second passageway 227b. The connector 273 electrically connects the third ohmic electrode 2 245, for example, the barrier layer 245b, to the third orifice path 227c. The connector 272 can be isolated from the first LED stack 223 by the top insulation layer 261. The connector 273 can also be isolated from the second LED stack 233 and the first LED stack 223 by the top insulation layer 261.
[0499] [0499] As shown in Fig. 39C, connector 272 can be formed on the sloping side surface of the first connection layer 253 and, consequently, a disconnection occurrence of connector 272 can be avoided compared to when the first connection layer 253 has a vertical side surface. In addition, as shown in FIG. 39D, connector 273 can be formed on the side surfaces of the second link layer 255, the second LED stack 233 and the first link layer 253 and the second link layer 255, the second LED stack 233 and the first layer of connection 253 have slanted side surfaces and, consequently, an occurrence of disconnection of connector 273 can be avoided.
[0500] [0500] Connectors 272 and 273 can be formed together in the same process. Connectors 272 and 273 can also be formed in conjunction with connector 271. In addition, connectors 272 and 273 can be formed from substantially the same material as those of the second ohmic electrode 1 239 and the third ohmic electrode 1 249 in conjunction with the second ohmic electrode 1 239 and the third ohmic electrode 1 249. However, the inventive concepts are not limited to these and connectors 272 and 273 can be formed from layers other than the second ohmic electrode 1 239 or the third ohmic electrode 1 249 and, therefore, they can be formed separately by a process to form the second ohmic electrode 1 239 and / or the third ohmic electrode 1
[0501] [0501] The bottom insulation layer 275 covers a bottom surface of the substrate 221. The bottom insulation layer 275 can have openings that expose the first passageways 227a, 227b and 227c under the substrate 221 and can also have an opening that exposes the bottom surface of the substrate 221.
[0502] [0502] The electrode pads 277a, 277b, 277c and 277d are disposed under the substrate 221. The electrode pads 277a, 277b and 277c are connected to the passageways 227a, 227b and 227c through the openings of the lower insulation layer 275 , respectively, and the electrode pad 277d is connected to substrate 221.
[0503] [0503] The electrode pads 277a, 277b and 277c are arranged for each pixel and are electrically connected to the first to third LED cells 223, 233 and 243 of each pixel. The 277d electrode pad can be arranged for each pixel. However, since substrate 221 is disposed continuously over a plurality of pixels, electrode 277d may not need to be disposed for each pixel.
[0504] [0504] When connecting the electrode pads 277a, 277b, 277c and 277d to the circuit board 251, a display device, according to an exemplary embodiment, can be provided.
[0505] [0505] From now on, a method of manufacturing the display apparatus will be described, according to an exemplary modality.
[0506] [0506] FIGS. 40A to 47B are planar and schematic cross-sectional views illustrating a method of manufacturing a display device, according to an exemplary embodiment. Each of the cross-sectional views is taken along an E-E line of a corresponding plane view.
[0507] [0507] Referring to FIGS. 40A and 40B, a first LED stack 223 is grown on a substrate 221. The substrate 221 can be, for example, a GaAs substrate. The first LED stack 223 is formed with semiconductor layers based on AlGaInP, and includes a first semiconductor layer of conductivity type 223a, an active layer and a second semiconductor layer of conductivity type 223b. Before the first LED stack 223 grows, a distributed Bragg reflector 222 can be formed first on substrate 221. The distributed Bragg reflector 222 can have, for example, a stack structure of alternating layers of AlAs and AlGaAs.
[0508] [0508] Then, grooves are formed in the substrate 221 and in the first LED stack 223 using a photolithography and engraving process. The grooves can pass through the substrate 221, or can be formed to be less than a thickness of the substrate 221, as shown in the figures.
[0509] [0509] Next, an insulating layer 225 is formed covering a side wall of each of the grooves and formed through the orifices 227a, 227b and 227c that fill the grooves. For example, after an insulation layer 225 covering a side wall of each groove is formed,
[0510] [0510] Referring to FIGS. 41A and 41B, a second LED battery 233 and a second ohmic electrode 2 235 can be coupled to the third LED battery 223 through the first connection layer
[0511] [0511] The second 233 LED stack is grown on a second substrate and the second ohmic electrode 2 235 is formed on the second 233 LED stack. The second 233 LED stack can be formed with AlGaInP-based semiconductor layers or layers semiconductors based on AlGaInN and may include a first semiconductor layer of conductivity type 233a, an active layer and a second semiconductor layer of conductivity type 233b. The second substrate can be a substrate, for example, a GaAs substrate, capable of growing AlGaInP-based semiconductor layers or a sapphire substrate, capable of growing AlGaInN-based semiconductor layers. A composition ratio of Al, Ga and In can be determined so that the second LED stack 233 can emit green light. The second ohmic electrode 2 235 is in ohmic contact with the second semiconductor layer of conductivity type 233b, for example, a semiconductor layer of type p. The second ohmic electrode 2 235 may include a reflective layer 235a to reflect the light generated in the second LED stack 233 and a barrier layer 235b.
[0512] [0512] The second ohmic electrode 2 235 is arranged to face the first LED stack 223 and is connected to the first LED stack 223 by the first link layer 253. Then the second substrate is removed from the second LED stack 233 using a chemical engraving technique or a laser removal technique, and the first semiconductor layer of conductivity type 233a is exposed. A surface roughened by surface texturing can be formed on the first exposed conductivity type semiconductor layer 233a.
[0513] [0513] According to an exemplary embodiment, before the formation of the first connection layer 253, an insulation layer and a reflective layer can be added to the first LED stack 223.
[0514] [0514] Referring to FIGS. 42A and 42B, a third LED battery 243 and a third ohmic electrode 2 245 can be connected to the second LED battery 233 through the second connection layer
[0515] [0515] First, the third LED stack 243 is grown on a third substrate and the third ohmic electrode 2 245 is formed on the third LED stack 243. The third LED stack 243 can be formed with semiconductor layers based on AlGaInP, and may include a first conductivity type semiconductor layer 243a, an active layer and a second conductivity type semiconductor layer 243b. The third substrate is a substrate capable of growing in a semiconductor layer based on gallium nitride and is different from the first substrate 221. A proportion of AlGaInN composition can be determined so that the third LED stack 243 can emit blue light. The third ohmic electrode 2 245 is in ohmic contact with the second semiconductor layer of conductivity type 243b, for example, a semiconductor layer of type p. The third ohmic electrode 2 245 may include a reflective layer 245a to reflect the light generated in the third LED stack 243 and a barrier layer 245b.
[0516] [0516] The third ohmic electrode 2 245 is arranged to face the second stack of LED 233 and is connected to the second stack of LED 233 by the second layer of connection 255. Then the third substrate is removed from the third stack of LED 243 using a chemical removal technique or a laser removal technique, and the first semiconductor layer of conductivity type 243a is exposed. A rough surface by surface texturing can be formed on the first exposed conductivity type semiconductor layer 243a.
[0517] [0517] According to an exemplary embodiment, before the second connection layer 255 is formed, an insulation layer and a reflective layer can be added to the second LED stack 233.
[0518] [0518] Referring to FIGS. 43A and 43B, in each pixel region, the third stack of LED 243 is removed, except for a region of a third subpixel B, standardizing the third stack of LED 243. In addition, in the region of the third subpixel B, an indented part can be formed in the third LED stack 243 and the barrier layer 245b can be exposed in the recessed part. The third LED stack 243 is formed to have an inclined side surface, as shown in FIG. 43B. For example, a photoresistor pattern with an inclined side surface can be formed using a reflector process of a photoresistor, and the third LED stack 243 can be recorded using the photoresistor pattern with the tilted side surface, so that the third stack of LED 243 having the inclined side surface can be formed.
[0519] [0519] Then, in regions other than that of the third subpixel B, the third ohmic electrode 2 245 and the second connection layer 255 are removed and the second LED stack 233 is exposed. The third ohmic electrode 245 and the second connection layer 255 can also be formed to have sloping side surfaces. In particular, an angle of inclination of a lateral surface of the second connection layer 255 may be substantially the same as an angle of inclination of a lateral surface of the third LED stack 243, but is not limited to these. The third ohmic electrode 2 245 is restricted near the region of the third subpixel B.
[0520] [0520] Meanwhile, in each pixel region, the second 233 LED stack is removed from the regions, except for a second G sub pixel region of each pixel, standardizing the second 233 LED stack. A second 233 LED stack from region of the second subpixel G partially overlaps with the third LED stack 243. As shown in Fig. 43B, the second LED stack 233 is also patterned to have an inclined side surface.
[0521] [0521] When standardizing the second 233 LED battery, the second ohmic electrode 2 235 is exposed. The second LED stack 233 can include an indented part, and the second ohmic electrode 2 235, for example, barrier layer 235b, can be exposed through the indented part.
[0522] [0522] Then, the second ohmic electrode 2 235 and the first connection layer 253 are removed and the first LED battery 223 is exposed. The second ohmic electrode 2 235 and the first connection layer 253 can also be standardized to have sloping side surfaces. In particular, an angle of inclination of a lateral surface of the first connection layer 253 can be substantially the same as an angle of inclination of a lateral surface of the second LED stack 233, but is not limited to that. The second ohmic electrode 2 235 is restricted close to the region of the second subpixel G. Furthermore, the first to third passageways 227a, 227b and 227c can be exposed together when the first LED stack 223 is exposed.
[0523] [0523] Meanwhile, in each pixel region, the first semiconductor layer of conductivity type 223a is exposed by standardizing the second semiconductor layer of conductivity type 223b from the first LED stack 223. The first semiconductor layer of conductivity type 223a can be exposed to have an elongated shape, as shown in FIG. 43A, but is not limited to this.
[0524] [0524] In addition, the pixel regions can be separated by standardization of the first 223 LED stack. Therefore, a region of the first subpixel R is defined. Here, the distributed Bragg reflector 222 can also be divided. As shown in Fig. 43B, the first LED stack 223 can be standardized to have an inclined side surface and the distributed Bragg reflector 222 can also have an inclined side surface. However, inventive concepts are not limited to these. For example, the distributed Bragg reflector 222 can be continuous over a plurality of pixels, instead of being divided. In addition, the first 223 LED stack can substantially have a vertical side surface. In addition, the first conductivity type semiconductor layer 223a can be continuous across a plurality of pixels instead of being divided into pixel regions.
[0525] [0525] Referring to FIGS. 44A and 44B, a first ohmic electrode 1 229a and a first ohmic electrode 2 229b are formed in the first LED stack 223. The first ohmic electrode 1 229a can be formed from, for example, an Au-Te alloy, an alloy of Au-Ge, or others, in the first semiconductor layer of exposed conductivity type 223a. The first ohmic electrode 2 229b can be formed from, for example, an Au-Be alloy, an Au-Zn alloy, or others, in the second semiconductor layer of conductivity type 223b. The first ohmic electrode 2 229b can be formed first and the first ohmic electrode 1 229a can be formed, or the first ohmic electrode 1 229a can be formed before the first ohmic electrode 2 229b is formed. The first ohmic electrode 2 229b can be connected to the first passageway 227a. The first ohmic electrode 1 229a may include a pad region and an extension and the extension may extend from the pad region towards the first passageway 227a.
[0526] [0526] In addition, for current propagation, the first ohmic electrode 2 229b can be arranged to at least partially surround the first ohmic electrode 1 229a. The first ohmic electrode 1 229a and the first ohmic electrode 1 229b are formed to have an extended length as shown in the figures, however, the inventive concepts are not limited to these. For example, the first ohmic electrode 1 229a and the first ohmic electrode 2 229b can be formed to be substantially circular in shape.
[0527] [0527] Referring to FIGS. 45A and 45B, a top insulation layer 261 covering the first to third LED batteries 223, 233 and 243 is formed. The upper insulating layer 261 can cover the first ohmic electrode 1 229a and the first ohmic electrode 2 229b. The top insulation layer 261 can also cover the side surfaces of the first to third LED cells 223, 233 and 243 and can cover a side surface of the distributed Bragg reflector 222. The top insulation layer 261 can be formed using a deposition of chemical vapor. According to some exemplary embodiments, the top insulating layer 261 can be formed using a spraying technique.
[0528] [0528] The upper insulating layer 261 may have an opening 261a that exposes the first ohmic electrode 1 229a, openings 261b and 261c that expose barrier layers 235b and 245b, openings 261d and 261e that expose the second and third passageways 227b and 227c and openings 261f and 261g that expose the first conductivity type semiconductor layer 233a of the second LED stack 233 and the first conductivity type semiconductor layer 243a of the third LED stack 243. The openings 261a to 261g can be formed using a photolithography and recording technique.
[0529] [0529] Referring to FIGS. 46A and 46B, a second ohmic electrode 1 239, a third ohmic electrode 1 249, and connectors 271, 272, 273 are formed. The second ohmic electrode 1 239 is formed at opening 261f and is in ohmic contact with the first semiconductor layer of conductivity type 233a. The third ohmic electrode 1,249 is formed at the opening 261g and is in ohmic contact with the first semiconductor layer of conductivity type 243a.
[0530] [0530] Connector 271 electrically connects the second ohmic electrode 1 239 and the third ohmic electrode 1 249 to the first ohmic electrode 1 229a. For example, connector 271 can be connected to the first ohmic electrode 1 229a exposed at opening 261a. The connector 271 is formed in the upper insulating layer 261 and is isolated from the second semiconductor layers of conductivity type 223b, 233b and 243b.
[0531] [0531] Connector 272 electrically connects the second ohmic electrode 2 235 to the second passageway 227b and connector 273 electrically connects the third ohmic electrode 2 245 to the third passageway 227c. Connectors 272 and 273 and are also arranged in the top insulation layer 261 to prevent short-circuiting the first to third LED batteries 223, 233 and 243.
[0532] [0532] Connectors 271, 272 and 273 are formed on the sloping side surfaces of the first and second connection layers 253 and 255, the second LED stack 233 and the third LED stack 243 and therefore it is possible to avoid disconnection due to to coverage problems in stages.
[0533] [0533] The second ohmic electrode 1 239, the third ohmic electrode 1 249 and connectors 271, 272, and 273 can be formed of substantially the same material in the same process. However, the inventive concepts are not limited to these, and connectors 271, 272 and 273 can be formed from different materials in different processes.
[0534] [0534] Next, with reference to FIGS. 47A and 47B, a lower insulating layer 275 is formed on the substrate 221. The lower insulating layer 275 can have openings that expose the first to third passageways 227a, 227b and 227c and an opening that exposes the bottom surface of the substrate. 221.
[0535] [0535] The electrode pads 277a, 277b, 277c, and 277d are formed in the bottom insulation layer 275. The electrode pads 277a, 277b, and 277c are connected to the first through third passageways 227a, 227b, and 227c, respectively, and the electrode pad 277d is connected to substrate 221.
[0536] [0536] Therefore, the electrode pad 277a is electrically connected to the second semiconductor layer of conductivity type 223b of the first LED stack 223 through the first through hole 227a, the electrode pad 277b is electrically connected to the second layer conductivity type semiconductor 233b from the second LED stack 233 through the second passageway 227b and the electrode pad 277c is electrically connected to the second conductivity type semiconductor layer 243b from the third LED stack 243 through the third passageway 227c . The first semiconductor layers of conductivity type 223a, 233a, and 243a from the first to the third LED stack 223, 233, and 243 are commonly electrically connected to the electrode pad 277d.
[0537] [0537] The electrode pads 277a, 277b, 277c and 277d of the substrate 221 are connected to the circuit board 251 of FIG. 35, so that a display device, according to an exemplary embodiment, will be provided. The circuit board 251 can include an active circuit or a passive circuit, and therefore the display device can be operated in an active or passive matrix manner.
[0538] [0538] FIG. 48 is a schematic cross-sectional view of an LED pixel for a display, according to another exemplary embodiment.
[0539] [0539] Referring to FIG. 48, the LED pixel 202 of the display apparatus, according to an exemplary embodiment, is substantially similar to the LED pixel 200 of the display apparatus of FIG. 36, except that the second 233 LED battery covers most regions of a first 223 LED battery, and the third 243 LED battery covers most regions of the second 233 LED battery. Thus, the light generated in a first subpixel R passes substantially through the second LED battery 233 and the third LED battery 243 and is emitted to the outside. In addition, the light generated in the second LED battery 233 passes substantially through the third LED battery 243 and is emitted to the outside.
[0540] [0540] The first stack of LED 223 can include an active layer with a narrow band of band compared to the second stack of LED 233 and the third stack of LED 243, and can emit light with a relatively long wavelength than the one emitted by the second battery of LED 233 and the third battery of LED 243. The second battery of LED 233 can include an active layer with a narrow band gap compared to the third battery of LED 243 and can emit light with a length of relatively longer wave than that emitted in the third 243 LED stack.
[0541] [0541] FIG. 49 is an enlarged view of a pixel of a display device, according to an exemplary embodiment, and FIGS. 50A and 50B are seen in cross section taken along the lines G-G and H-H of FIG. 49, respectively.
[0542] [0542] Referring to FIGS. 49, 50A and 50B, the pixel, according to an exemplary embodiment, is generally similar to the pixel described with reference to FIGS. 38, 39A, 39B and 39C, except that the second 233 LED battery covers most regions of a first 223 LED battery and a third 243 LED battery covers most regions of the second 233 LED battery. third passageways 227a, 227b, and 227c can be arranged outside the second LED stack 233 and the third LED stack 243.
[0543] [0543] An upper surface of the first LED stack 223 exposes the orifices 227a, 227b and 227c, as shown in the figures, however, according to some exemplary embodiments, the orifices 227a, 227b and 227c can be omitted .
[0544] [0544] A portion of a first ohmic electrode 1 229a and a portion of a second ohmic electrode 2 239 can be arranged under the third LED stack 243. To this end, the first ohmic electrode 1 229a can be formed before the second battery of LED 233 is connected to the first battery of LED 223 and the second ohmic electrode 1 239 can also be formed before the third battery of LED 243 is connected to the second battery of LED 233.
[0545] [0545] The light generated in the first LED battery 223 passes substantially through the second LED battery 233 and the third LED battery 243 and is emitted to the outside. The light generated in the second LED battery 233 passes substantially through the third LED battery 243 and is emitted to the outside. Thus, a first bonding layer 253 and a second bonding layer 255 can be formed of light transmitting materials, and a second ohmic electrode 2 235 and a third ohmic electrode 2 245 can be formed of transparent conductive layers.
[0546] [0546] An indented piece is formed on the third LED stack 243 to expose the third ohmic electrode 2 245 and an indented piece is formed continuously on the third LED stack 243 and the second LED stack 233 to expose the second ohmic electrode 2 235 The second ohmic electrode 2 235 and the third ohmic electrode 2 245 are electrically connected to the second passageway 227b and the third passageway 227c via connectors 272 and 273, respectively.
[0547] [0547] Furthermore, since the indented part is formed in the third LED stack 243, the second ohmic electrode 239 formed in the first conductivity type semiconductor layer 233a of the second LED stack 233 can be exposed. In addition, since the indented part is formed continuously on the third LED stack 243 and the second LED stack 233, the first ohmic electrode 229a formed on the first conductivity type semiconductor layer 223a of the first LED stack 223 can be exposed . The connector 271 can connect the first ohmic electrode 1 229a and the second ohmic electrode 1 239 to the third ohmic electrode 1 249. The third ohmic electrode 1 249 can be formed together with connector 271, and can be connected to the pad regions of the first ohmic electrode 1 229a and the second ohmic electrode 1 239.
[0548] [0548] A portion of the first ohmic electrode 1 229a and a portion of the second ohmic electrode 1 239 are disposed under the third LED stack 243, but the inventive concepts are not limited to these. The portions of the first ohmic electrode 1 229a and the portion of the second ohmic electrode 1 239 arranged under the third LED stack 243 can be omitted. In addition, the second ohmic electrode 1 239 can be omitted, and the connector 271 can be in ohmic contact with the first semiconductor layer of conductivity type 233a.
[0549] [0549] As in the exemplary embodiment described above, the third LED stack 243, the second link layer 255, the second LED stack 233 and the first link layer 253 include inclined side surfaces, connectors 271 and 273 are formed on the inclined side surfaces, and the connector 272 is formed on the included side surface of the first connection layer 253.
[0550] [0550] According to exemplary modalities, a plurality of pixels can be formed at the wafer level through the connection of the wafer and, thus, the individual LED assembly step can be avoided.
[0551] [0551] Furthermore, since orifice pathways 227a, 227b and 227c are formed on substrate 221 and are used as current paths, it is not necessary to remove substrate 221. Thus, a growth substrate used to grow the first LED stack 223 can be used as substrate 221 without removing the growth substrate from the first LED stack 223. However, the inventive concepts are not limited to these, and substrate 221 can be removed from the first LED stack 223 and the first stack of LED 223 can be connected to circuit board 251 using a link layer. Here, connectors 271, 272 and 273 can be connected directly to circuit board 251. For this purpose, the first stack of LEDs 223 and the connecting layer can be formed to have sloping side surfaces.
[0552] [0552] In addition, the first LED battery 223, the second LED battery 233 and the third LED battery 243 are stacked in the vertical direction and, consequently, when the first to the third LED batteries 223, 233 and 243 and the first and second connection layer 253 and 255 have vertical side surfaces, it can be difficult to safely form connectors 271, 272 and 273 on vertical side surfaces. According to exemplary modalities, a lateral surface on which the wiring, such as connectors 271, 272 and 273, must be formed between the lateral surfaces of the first to the third LED batteries 223, 233 and 243, and the first and second layers of connection 253 and 255 can be tilted, so that the wiring can be formed safely. Thus, it is possible to increase the reliability of the display device.
[0553] [0553] FIG. 51 is a schematic plan view of a display apparatus according to an exemplary embodiment.
[0554] [0554] Referring to FIG. 51, the display apparatus includes a circuit board 401 and a plurality of light-emitting devices 400.
[0555] [0555] Circuit board 401 may include a circuit for passively driving the matrix or active driving the matrix. In an exemplary embodiment, circuit board 401 may include interconnect lines and resistors thereon. In another exemplary embodiment, circuit board 401 may include interconnect lines, transistors and capacitors. The circuit board 401 may include a circuit for passively driving the matrix or active driving the matrix.
[0556] [0556] A plurality of light-emitting devices 400 are arranged on circuit board 401. Each light-emitting device 400 can constitute a pixel. The light emitting device 400 includes electrode pads 481a, 481b, 481c and 481d electrically connected to the circuit board 401. The light emitting device 400 can also include a substrate 441 on the top surface thereof. Since the light-emitting devices 400 are spaced apart, the substrates 441 arranged on the upper surfaces of the light-emitting devices 400 are also spaced apart from each other.
[0557] [0557] The configuration of the light emitting device 400 will be described in detail with reference to FIGS. 52A, 52B and 52C. FIG. 52A is a schematic plan view of the light emitting device 400 according to an exemplary embodiment, FIG. 52B is a cross-sectional view taken along a line A-A of FIG. 52A, and FIG. 52C is a cross-sectional view taken along line B-B of FIG. 52A. Although it is shown and described here that the electrode pads 481a, 481b, 481c and 481d are arranged on the upper side, however, the inventive concepts are not limited to these, and the light-emitting device 400, according to some exemplary modalities , can be inverted connected to circuit board 401 of FIG. 51 and, in this case, the electrode pads 481a, 481b, 481c and 481d can be arranged on the underside of the light emitting device 400.
[0558] [0558] Referring to FIGS. 52A, 52B and 52C, the light-emitting device 400 includes substrate 441, electrode pads 481a, 481b, 481c and 481d, a first stack of LED 423, a second stack of LED 433, a third stack of LED 443, a first transparent electrode 435, a third transparent electrode 445, an ohmic electrode 427, a first color filter 447, a second color filter 457, a first connection layer 449, a second connection layer 459 and an insulation layer 461 .
[0559] [0559] Substrate 441 can support semiconductor cells 423, 433 and 443. In addition, substrate 441 can be a growth substrate for the growth of the third LED stack 443. For example, substrate 441 can be a substrate for sapphire or a gallium nitride substrate, in particular, a standardized sapphire substrate. The LED batteries are arranged on the substrate 441 in the order of the third LED battery 443, the second LED battery 433 and the first LED battery 423.
[0560] [0560] In an exemplary embodiment, a single third LED stack can be arranged on a 441 substrate, and therefore, the light-emitting device 400 can have a single-pixel single chip structure. According to another exemplary embodiment, the substrate 441 can be omitted and the bottom surface of the third LED stack 443 can be exposed. In this case, a rough surface can be formed on the bottom surface of the third stack of LED 443 by surface textures.
[0561] [0561] According to yet another exemplary embodiment, a plurality of third LED stack 443 can be arranged on a substrate 441, and the second LED stack 433 and the first LED stack 423 can be arranged on each third LED stack. 443. Therefore, the light-emitting device 400 may include a plurality of pixels.
[0562] [0562] The first LED battery 423, the second LED battery 433 and the third LED battery 443 include a first semiconductor layer of conductivity type 423a, 433b or 443a, a second semiconductor layer of conductivity type 423b, 433b or 443b and an active layer interposed between them. The active layer can have a multi-quantum well structure.
[0563] [0563] For LED cells 423, 433 and 443, the closer to substrate 441 the LED cell is, the smaller the wavelength light can be emitted from the LED cell. For example, the first 423 LED battery can be an inorganic light emitting diode that emits red light, the second 433 LED battery can be an inorganic light emitting diode that emits green light, and the third 443 LED battery can be an inorganic LED emitting blue light. The first 423 LED stack can include AlGaInP-based semiconductor layers, the second 433 LED stack can include AlGaInN-based or AlGaInN-based semiconductor layers, and the third 443 LED stack can include AlGaInN-based semiconductor layers. However, the inventive concepts are not limited to these, and when LED cells include micro LEDs, the LED stack positioned closest to substrate 440 can emit light with the longest wavelength or light with the intermediate wavelength that the stack of LEDs arranged above, without adversely affecting the operation and without the need for color filters due to the small form factor of a micro LED.
[0564] [0564] The first semiconductor layers of conductivity type 423a, 433a and 443a of the respective LED cells 423, 433 and 443 can be semiconductor layers of type n and the second semiconductor layers of conductivity type 423b, 433b and 443b of the respective LED cells 423 , 433 and 443 can be p-type semiconductor layers. In particular, the upper surface of the first 423 LED stack can be a n 423a semiconductor layer, the upper surface of the second 433 LED stack can be a n 433a semiconductor layer and the upper surface of the third 443 LED stack it can be a p 443b type semiconductor layer. That is, the order of the semiconductor layers is reversed only in the third stack of LED 443. Therefore, the p-type semiconductor layers of the second stack of LED 433 and the third stack of LED 443 are arranged facing each other. However, the inventive concepts are not limited to these, and the p-type semiconductor layer 423b of the first LED stack 423 and the p-type semiconductor layer 433b of the second LED stack 433 can be arranged facing each other. In addition, the type 433a semiconductor layer of the second LED stack 433 and the type 443a semiconductor layer of the third LED stack 443 can be arranged facing each other, or the type 423a semiconductor layer of the first LED stack 423 and the type 433a semiconductor layer of the second LED stack 433 can be arranged facing each other.
[0565] [0565] In the first LED stack 423, the first semiconductor layer of conductivity type 423a can have substantially the same area as the second semiconductor layer of conductivity type 423b and thus the first semiconductor layer of conductivity type 423a and the second semiconductor layer of conductivity type 423b can overlap with each other. Also in the second LED stack 433, the first semiconductor layer of conductivity type 433a may have substantially the same area as the second semiconductor layer of conductivity type 433b and thus the first semiconductor layer of conductivity type 433a and the second layer semiconductor conductivity type 433b may overlap with each other. In the third LED stack 443, the second semiconductor layer of conductivity type 443b can be arranged in a partial region of the first semiconductor layer of conductivity type 443a and, thus, the first semiconductor layer of conductivity type 443a is partially exposed.
[0566] [0566] The first 423 LED battery and the second 433 LED battery can be arranged in a partial region of the third 443 LED battery. In addition, the first and second LED batteries 423 and 433 can be arranged in the upper region of the second semiconductor layer of conductivity type 443b. More specifically, the second LED stack 433 can be arranged in a partial region of the second semiconductor layer of conductivity type 443b, and the first LED stack 423 can be arranged in a partial region of the second LED stack 433. The second battery 433 LED can include a region disposed outside the first 423 LED stack and the third 443 LED stack can include a region disposed outside the second 433 LED stack.
[0567] [0567] The first battery of LED 423 is disposed away from the substrate 441, the second battery of LED 433 is disposed below the first battery of LED 423 and the third battery of LED 443 is disposed below the second battery of LED 433. The first 423 LED battery emits light with a wavelength greater than the second and third LED batteries 433 and 443, so that the light generated in the first 423 LED battery can be emitted to the outside through the second and third battery cells. LED 433 and 443 and substrate 441. In addition, the second stack of LED 433 emits light with a wavelength greater than the third stack of LED 443, so that the light generated in the second stack of LED 433 can be emitted to the through the third LED stack 443 and the substrate 441. However, the inventive concepts are not limited to these and, when the LED cells include micro LEDs, the LED stack positioned closest to the substrate 440 can emit light with the longer wavelength or compressed light intermediate wave that the LED stack arranged above, without adversely affecting the operation or requiring color filters due to the small form factor of a micro LED.
[0568] [0568] The first transparent electrode 425 is in ohmic contact with the second semiconductor layer of conductivity type 423b of the first LED stack 423 and transmits light generated in the first LED stack 423. The first transparent electrode 425 can be formed by a layer metal or a conductive oxide layer that is transparent to red light.
[0569] [0569] As shown in Fig. 52B, the first transparent electrode 425 can include a protruding portion outside the first LED stack 423. That is, the first transparent electrode 425 can include an exposed region outside the first LED stack 423.
[0570] [0570] The ohmic electrode 427 is in ohmic contact with the first semiconductor layer of conductivity type 423a of the first LED stack layer 423. In an exemplary embodiment, the ohmic electrode 427 can include a reflective metal layer and therefore it can reflect the light generated in the first LED stack 423 towards substrate 441. The ohmic electrode 427 can be formed, for example, by Au-Te, Au-Ge or other alloys. In another exemplary embodiment, the ohmic electrode 427 can be formed from a layer of material transparent to red light, such as a layer of conductive oxide.
[0571] [0571] The ohmic electrode 427 can cover most of the region of the first 423 LED battery, but is not limited to this one, and may be partially in contact with the first conductivity type 423a semiconductor layer.
[0572] [0572] The second transparent electrode 435 in ohmic contact with the second semiconductor layer of conductivity type 433b of the second LED cell 433. As shown in the figure, the second transparent electrode 435 is in contact with a lower surface of the second LED cell 433 between the second LED battery 433 and the third LED battery 443. In addition, as shown in FIG. 52B, the second transparent electrode 435 can include a region protruding out of the second LED cell 433. That is, the second transparent electrode 435 can include a region exposed outside the second LED cell 433. The second transparent electrode 435 can be formed by a layer of metal or a layer of conductive oxide that is transparent to red light and green light.
[0573] [0573] The third transparent electrode 445 is in ohmic contact with the second semiconductor layer of conductivity type 443b of the third LED stack 433. The third transparent electrode 445 can be arranged between the second LED stack 433 and the third LED stack 443 and is in contact with an upper surface of the third 443 LED stack. The third transparent electrode 445 can be formed by a metal layer or a conductive oxide layer that is transparent to red light and green light. The third transparent electrode 445 can also be transparent to blue light. The third transparent electrode 445 is in ohmic contact with the second semiconductor layer of conductivity type 443b of the third LED stack 433.
[0574] [0574] The first transparent electrode 425, the second transparent electrode 435 and the third transparent electrode 445 can assist the current distribution by being in ohmic contact with the p-type semiconductor layer of each LED cell. Examples of the conductive oxide layer used for the first, second and third transparent electrodes 425, 435 and 445 include SnO2, InO2, ITO, ZnO, IZO or others. In addition, the first, second and third pads of transparent electrodes 425, 435 and 445 can be used as a chemical stopper layer, and the exposed portion and the unexposed portion may be of different thickness.
[0575] [0575] The first color filter 447 can be disposed between the third transparent electrode 445 and the second battery of LED 433 and the second color filter 457 can be disposed between the second battery of LED 433 and the first battery of LED 423. The first 447 color filter transmits light generated in the first and second LED batteries 423 and 433 and reflects the light generated in the third 443 LED battery. The second 457 color filter transmits light generated in the first 423 LED battery and reflects the light generated in the second stack of LED 433. Therefore, the light generated in the first stack of LED 423 can be emitted outwards through the second stack of LED 433 and the third stack of LED 443, and the light generated in the second stack of LEDs. LED 433 can be emitted to the outside through the third battery of LED 443. In addition, the light generated in the second battery of LED 433 can be prevented from being lost by being incident in the first battery of LED 423, or the light generated in the third 443 LED battery can be prevented from being due to being incident on the second 433 LED battery.
[0576] [0576] In some exemplary embodiments, the second color filter 457 can reflect the light generated in the third LED stack 443.
[0577] [0577] The first and second color filters 447 and 457 are, for example, a low pass filter that passes only in a low frequency band, that is, a long wavelength band, a band pass filter which passes only one band of predetermined wavelength or a band interrupt filter that blocks only one band of predetermined wavelength. In particular, the first and second color filters 447 and 457 can be formed by alternately stacking insulation layers with different refractive indexes, for example, they can be formed by alternately stacking the TiO2 insulation layer and the insulation layer of SiO2. In particular, the first and second color filters 447 and 457 may include a distributed Bragg reflector (DBR). The interruption band of the distributed Bragg reflector can be controlled by adjusting the thickness of TiO2 and SiO2. The low-pass filter and the band-pass filter can also be formed by layers of insulation stacked alternately with different refractive indices.
[0578] [0578] The first link layer 449 joins the second stack of LED 433 to the third stack of LED 443. The first link layer 449 substantially covers the first color filter 447 and is connected to the second transparent electrode 435. For example, the the first bonding layer 449 can be a transparent organic layer or a transparent inorganic layer. Examples of the organic layer include SU8, poly (methylmethacrylate) (PMMA), polyimide, parylene and benzocyclobutene (BCB), examples of the inorganic layer include Al2O3, SiO2, SiNx or others. The first bonding layer 449 can also be formed of spin-on glass (SOG). The organic layers can be connected to a high vacuum and a high pressure, and the inorganic layers can be connected to a high vacuum, in a state in which the surface energy is modified using plasma or others, after planarizing the surface by a process of mechanical chemical polishing, for example.
[0579] [0579] The second layer of connection 459 couples the second battery of LED 433 to the first pile of LED 423. As shown in the figure, the second layer of connection 459 can cover the second color filter 457 and be in contact with the first electrode transparent 425. The second bonding layer 459 can be formed from substantially the same material as the first bonding layer 449 described above.
[0580] [0580] The insulation layer 461 covers the side surfaces and the upper region of the first, second and third LED batteries 423, 433 and 443. The first color filter 447 can be placed between the third transparent electrode 445 and the second battery of LED 433 and the second color filter 457 can be arranged between the second LED stack 433 and the first LED stack 423. In another exemplary embodiment, the insulation layer 461 may contain a light-reflecting material or a layer of light blocking as the light absorbing layer to prevent optical interference with the adjacent light emitting device. For example, the insulating layer 461 can include a distributed Bragg reflector that reflects red light, green light and blue light, or a SiO2 layer with a reflective metallic layer or a highly reflective organic layer deposited on it. Alternatively, the insulating layer 461 may contain an absorbent layer, such as a black epoxy, to block light. The light blocking layer can increase the contrast ratio of an image, preventing optical interference between light-emitting devices.
[0581] [0581] The insulation layer 461 can have openings 461a, 461b, 461c, 461d and 461e for electrical paths. For example, insulation layer 461 includes openings 461a, 461b, 461c, 461d and 461e to expose the ohmic electrode 427, the first transparent electrode 425, the second and third transparent electrodes 435 and 445 and the second and third LED batteries 433 and 443. Opening 461a exposes the ohmic electrode 427, opening 461b exposes the first conductivity-type semiconductor layer 433a from the second LED stack 433 and opening 461c exposes the first conductivity-type semiconductor layer 443a from the third LED stack 443a Opening 461d exposes the first transparent electrode 425 and the opening 461e exposes the second transparent electrode 435 and the third transparent electrode 445 together. In another exemplary embodiment, the second transparent electrode 435 and the third transparent electrode 445 can be exposed through different openings. However, when the second and third transparent electrode pads 435 and 445 are exposed through an opening 461e, the second and third transparent electrode pads 435 and 445 can be exposed to a relatively large extent.
[0582] [0582] The electrode pads 481a, 481b, 481c and 481d are arranged above the first LED battery 423, and are electrically connected to the first, second and third LED batteries 423, 433 and 443. The electrode pads 481a, 481b , 481c and 481d may include the first, second and third electrode pads 481a, 481b and 481c and the common electrode pad. The electrode pads 481a, 481b, 481c and 481d can be arranged in the insulation layer 461 and be connected to the ohmic electrode 427 exposed through the openings 461a, 461b, 461c, 461d and 461e of the insulation layer 461, the first, second and third transparent electrodes 425, 435 and 445, and the first semiconductor layers of conductivity type 433a and 443a of the second and third LED batteries. For example, the first electrode pad 481a can be connected to ohmic electrode 427 through opening 461a. The first electrode pad 481a is electrically connected to the first conductivity type semiconductor layer 423a of the first LED stack 423 through the ohmic electrode 427.
[0583] [0583] In addition, the second electrode pad 481b can be connected to the first semiconductor layer of conductivity type 433a of the second LED stack 433 through the opening 461b of the insulation layer 461 and the third electrode pad 481c can be electrically connected. to the first conductivity type semiconductor layer 443a of the third LED stack 443 through opening 461c of insulation layer 461.
[0584] [0584] The common electrode pad 481d can be connected in common to the first transparent electrode 425, the second transparent electrode 435 and the third transparent electrode 445 through the openings 461d and 461e. Therefore, the common electrode pad 481d is electrically connected in common to the second semiconductor layer of conductivity type 423b of the first LED stack 423, the second semiconductor layer of conductivity type 433b of the second LED stack 433 and the second layer of conductivity type semiconductor 443b from the third LED stack 443.
[0585] [0585] According to an exemplary embodiment, the first 423 LED battery is electrically connected to the 481d and 481a electrode pads, the second 433 LED battery is electrically connected to the 481d and 481b electrode pads and the third 443 LED battery. is electrically connected to the 481d and 481c electrode pads. Therefore, the anodes of the first 423 LED battery, the second 433 LED battery and the third 443 LED battery are electrically connected in common to the electrode pad 481d, and their cathodes are electrically connected to the first, second and third pads electrodes 481a, 481b and 481c, respectively. Thus, the first, second and third LED batteries 423, 433 and 443 can be activated independently.
[0586] [0586] While the first, second and third electrode pads 481a, 481b and 481c are described as being electrically connected to the first semiconductor layers of conductivity type 423a, 433a and 443a and the common electrode pad 481d is described as being electrically connected to the second semiconductor layers of conductivity type 423b, 433b and 443b, the inventive concepts are not limited to these. For example, the first, second and third electrode pads 481a, 481b and 481c can be electrically connected to the second semiconductor layers of conductivity type 423b, 433b, 443b and the common electrode pad 481d can be electrically connected to the first layers conductivity type 423a, 433a and 443a semiconductors.
[0587] [0587] FIGS. 53, 54, 55, 56, 57A, 57B, 58A, 58B, 59A, 59B, 60A, 60B, 61A, 61B, 62A, 62B, 63A, 63B, 64A, and 64B are flat schematic views and cross-sectional views that illustrate a method of manufacturing the light-emitting device 400, according to an exemplary embodiment. In the figures, each plan view corresponds to a plan view of FIG. 52A, and each cross-sectional view corresponds to the cross-sectional view taken from line A-A of FIG. 52A.
[0588] [0588] Referring to FIG. 53, the first LED stack 423 is grown on a first substrate 421. The first substrate 421 can be a GaAs substrate, for example. The first LED stack 423 is formed by semiconductor layers based on AlGaInP and includes the first semiconductor layer of conductivity type 423a, the active layer and the second semiconductor layer of conductivity type 423b. Here, the first type of conductivity can be type n and the second type of conductivity can be type p.
[0589] [0589] The first transparent electrode 425 can be formed in the first stack of LED 423. The first transparent electrode 425 can be formed from a layer of conductive oxide, such as SnO2, InO2, ITO, ZnO, IZO or others.
[0590] [0590] Referring to FIG. 54, the second LED stack 433 is grown on a second substrate 31 and the second transparent electrode 435 is formed on the second LED stack 433. The second LED stack 433 is semiconductor layers based on AlGaInP or AlGaInN and can include the first layer semiconductor of conductivity type 433a, the active layer and the second semiconductor layer of conductivity type 433b. The active layer can include a well layer based on AlGaInP or AlGaInN. Here, the first type of conductivity can be type n and the second type of conductivity can be type p.
[0591] [0591] The second substrate 31 can be a substrate on which the AlGaInP-based semiconductor layer can be grown, for example, a GaAs substrate or a substrate on which the AlGaInN-based semiconductor layer can be grown, for example, a substrate of GaN or a sapphire substrate. The composition ratio of the well layer can be determined so that the second 433 LED stack emits green light. The second transparent electrode 435 is in ohmic contact with the second semiconductor layer of conductivity type 433b. The second transparent electrode 435 can be formed from a conductive oxide layer, such as SnO2, InO2, ITO, ZnO, IZO or others.
[0592] [0592] Referring to FIG. 55, the third LED stack 443 is grown on a third substrate 441 and the third transparent electrode 445 and the first color filter 447 are formed on the third LED stack 443. The third LED stack 443 is formed by semiconductor layers based on AlGaInN and includes the first semiconductor layer of conductivity type 443a, the active layer and the second semiconductor layer of conductivity type 443b. The active layer can also include a well layer based on AlGaInN. Here, the first type of conductivity can be type n and the second type of conductivity can be type p.
[0593] [0593] The third substrate 441 is a substrate on which a semiconductor layer based on gallium nitride can be grown and can be different from sapphire substrate or a GaN substrate. The composition ratio of the AlGaInN layer can be determined so that the third stack of LED 443 emits blue light. The third transparent electrode 445 is in ohmic contact with the second semiconductor layer of conductivity type 443b. The third transparent electrode 445 can be formed from a conductive oxide layer, such as SnO2, InO2, ITO, ZnO, IZO or others.
[0594] [0594] Since the first color filter 447 is substantially the same as that described with reference to FIGS. 52A, 52B, and, 52C, detailed descriptions will be omitted to avoid redundancy.
[0595] [0595] Referring to FIG. 56, the second LED stack 433 described with reference to FIG. 54 is connected to the third LED stack 443 of FIG. 55.
[0596] [0596] The first color filter 447 and the second transparent electrode 435 are connected so that they are facing each other. For example, layers of bonding material are formed in the first color filter 447 and the second transparent electrode 435, respectively, and by connecting the first color filter 447 and the second transparent electrode 435, the first connection layer 449 can be formed. The layers of the bonding material can be, for example, a transparent organic layer or a transparent inorganic layer. Examples of the organic layer include SU8, poly (methylmethacrylate) (PMMA), polyimide, parylene, benzocyclobutene (BCB) or others, and examples of the inorganic layer include Al2O3, SiO2, SiNx or others. In addition, the first bonding layer 449 can be formed using spin-on glass (SOG).
[0597] [0597] Then, the second substrate 31 is removed from the second stack of LED 433, using techniques such as laser removal, chemical removal or others. Therefore, the first conductivity type semiconductor layer 433a of the second LED stack 433 is exposed from above. A surface roughened by surface texturing may be formed on the surface of the first semiconductor layer of exposed conductivity type 433a.
[0598] [0598] Then, the second color filter 457 is formed on the first exposed semiconductor layer 433a of conductivity type of the second LED stack 433. Since the second color filter 457 is substantially the same as that described with reference to FIGS . 52A, 52B, and, 52C, detailed descriptions will be omitted to avoid redundancy.
[0599] [0599] The first LED stack 423 of FIG. 53 is connected to the second LED battery 433. The second color filter 457 and the first transparent electrode 425 can be connected to each other. For example, layers of bonding material are formed in the second color filter 457 and the first transparent electrode 425, respectively, and by connecting the second color filter 457 and the first transparent electrode 425, the second connection layer 459 can be formed. The layers of the bonding material can be, for example, a transparent organic layer or a transparent inorganic layer as described above.
[0600] [0600] Then, the first substrate 421 is removed from the first stack of LED 423. The first substrate 421 can be removed, for example, a wet etching technique. Therefore, the first conductivity type semiconductor layer 423a is exposed. The surface of the first conductivity type 423a semiconductor layer exposed can be textured to improve the efficiency of light extraction, which makes it possible to form a rough surface or light extraction structure on the surface of the first conductivity type 423a semiconductor layer .
[0601] [0601] Referring to FIGS. 57A and 57B, the first 423 LED battery is standardized to expose the first transparent electrode
[0602] [0602] Referring to FIGS. 558A and 58B, subsequently, the first transparent electrode 425, the second connection layer 459 and the second color filter 457 are standardized so that the first conductivity type semiconductor layer 433a of the second LED stack 433 is exposed. As shown in Fig. 58A, the first transparent electrode 425 is standardized so that part of the first transparent electrode 425 remains outside the first LED stack 423 in a flat view.
[0603] [0603] Referring to FIGS. 59A and 59B, the first and second semiconductor layers of conductivity type 433a and 433b are standardized to expose the second transparent electrode 435. As shown in Fig. 59A, the first semiconductor layer of conductivity type 433a is standardized so that a part of the first semiconductor layer of conductivity type 433a remains outside the first LED stack 423 in a plan view. The second transparent electrode 435 can be used as a recording stopper layer during the pattern of the first and second semiconductor layers of conductivity type 433a and 433b. Therefore, on the second transparent electrode 435, a part disposed outside the second LED stack 433 can be thinner than a part disposed below the second LED stack 433, so that a step is formed.
[0604] [0604] Referring to FIGS. 60A and 60B, the second transparent electrode 435, the first connection layer 449 and the first color filter 447 are sequentially standardized to expose the third transparent electrode 445. The third transparent electrode 445 can be used as a recording stop layer, so that a step can also be formed on the third transparent electrode 445. That is, on the third transparent electrode 445, an exposed part outside the first color filter 447 can be relatively thin compared to a part disposed below the first color filter. color 447.
[0605] [0605] As shown in Fig. 58A, the second transparent electrode 435 is standardized so that a part of the second transparent electrode 435 remains outside the second LED stack 433 in a plan view. The second exposed transparent electrode 435 is disposed adjacent to the first exposed transparent electrode 425.
[0606] [0606] Referring to FIGS. 61A and 61B, the third transparent electrode 445 and the second semiconductor layer of conductivity type 443a are standardized to expose the first semiconductor layer of conductivity type 443a.
[0607] [0607] A part of the third transparent electrode 445 is exposed to the outside of the second battery of LED 433 to be seen in a flat view. The third exposed transparent electrode 445 is disposed adjacent to the second exposed transparent electrode 435.
[0608] [0608] Referring to FIGS. 62A and 62B, the ohmic electrode 427 is formed in the first semiconductor layer of conductivity type 423a of the first LED stack 423. The ohmic electrode 427 is in ohmic contact with the first semiconductor layer of the conductivity type 423a and can be formed of a layer metal, such as AuTe or AuGe
[0609] [0609] Referring to FIGS. 63A and 63B, insulation layer 461 covering the first, second and third LED batteries 423, 433 and 443 is formed. The insulation layer 461 can be formed by a single layer or multiple layers of SiO2, Si3N4, SOG or others. Alternatively, the insulating layer 461 may include a light-reflecting material or a light-absorbing layer to prevent optical interference with the adjacent light-emitting device. For example, the insulating layer 461 can include a distributed Bragg reflector that reflects red light, green light and blue light, or a SiO2 layer with a reflective metallic layer or a highly reflective organic layer deposited on it. Alternatively, the insulating layer 461 may include, for example, black epoxy as a light-absorbing material. The light-reflecting layer or the light-absorbing layer prevents optical interference between the light-emitting devices, which results in an increase in the contrast ratio of the image.
[0610] [0610] The insulation layer 461 can cover the top surface and the side surfaces of the first, second and third LED batteries 423, 433 and 443. The insulation layer
[0611] [0611] Insulation layer 461 is standardized to include openings 461a, 461b, 461b, 461c, 461d and 461e to expose ohmic electrode 427, the first semiconductor layers of conductivity type 433a and 443a and the first, second and third transparent electrode pads 425, 435 and 445. In particular, opening 461a can expose the second transparent electrode 435 and the third transparent electrode 445 together.
[0612] [0612] Although the ohmic electrode 427, the first semiconductor layer of conductivity type 433a and the first semiconductor layer of conductivity type 443a are shown and described as exposed by an opening, each can be exposed through a plurality of openings. In addition, the second and third transparent electrode pads 435 and 445 can be exposed through different openings, respectively, and the first, second and third transparent electrode pads 425, 435 and 445 each can be exposed through a plurality of openings. .
[0613] [0613] Referring to FIGS. 64A and 64B, electrode pads 481a, 481b, 481c and 481d are formed in insulation layer 461. Electrode pads 481a, 481b, 481c and 481d include the first electrode pad 481a, the second electrode pad 481b, the third electrode pad 481c and the common electrode pad 481d.
[0614] [0614] The electrode pads 481a, 481b, 481c and 481d include the first electrode pad 481a, the second electrode pad 481b, the third electrode pad 481c and the common electrode pad 481d. Thus, the common electrode pad 481d is electrically connected in common to the anodes of the first, second and third LED batteries 423, 433 and 443. In particular, the common electrode pad 481d can be connected simultaneously to the second transparent electrode 435 and the third transparent electrode 445 through an opening 461e.
[0615] [0615] The first electrode pad 481a is connected to ohmic electrode 427 and electrically connected to the cathode of the first LED stack 423, that is, the first semiconductor layer of conductivity type 423a through opening 461a. The second electrode pad 481b is electrically connected to the cathode of the second LED stack 433, that is, the first semiconductor layer of conductivity type 433a through opening 461b, and the third electrode pad 481c is electrically connected to the cathode of the third cell of LED 443, that is, the first semiconductor layer of conductivity type 443a through opening 461c.
[0616] [0616] The electrode pads 481a, 481b, 481c and 481d are electrically separated from each other, so that each of the first, second and third LED batteries 423, 433 and 443 are electrically connected to two electrode pads and is adapted to be triggered independently.
[0617] [0617] Subsequently, the light emitting device 400 of FIG. 52A, according to an exemplary embodiment, is provided by dividing substrate 441 into regions of light emitting devices.
[0618] [0618] As shown in Fig. 64A, electrode pads 481a, 481b, 481c and 481d can be arranged in four corners of each light emitting device 400. In addition, electrode pads 481a, 481b, 481c and 481d can have a substantially rectangular shape, but the inventive concepts are not limited to them.
[0619] [0619] Still, although substrate 441 is described as being divided, substrate 441 can be removed so that the surface of the first conductivity type 443 semiconductor layer exposed can be textured.
[0620] [0620] A light emitting device, according to an exemplary modality, in which anodes of the first, second and third LED batteries 423, 433 and 443 are electrically connected in common and their cathodes are connected independently. However, the inventive concepts are not limited to them, and the anodes of the first, second and third LED batteries 423, 433 and 443 can be connected independently to the electrode pads, and the cathodes can be electrically connected in common.
[0621] [0621] The light emitting device 400 can include the first, second and third LED batteries 423, 433 and 443 to emit red, green and blue light and therefore can be used as a single pixel on a display device. As described with reference to FIG. 51, a display apparatus may be provided by arranging a plurality of light-emitting devices 400 on circuit board 401. Since the light-emitting device 400 includes the first, second and third LED batteries 423, 433 and 443 , the subpixel area in a pixel can be increased. In addition, the first, second and third LED batteries 423, 433 and 443 can be mounted by mounting a light emitting device 400, thereby reducing the number of assembly processes.
[0622] [0622] According to the illustrated embodiment, the second transparent electrode 435 and the third transparent electrode 445 can be exposed together through an opening 461e, and the common electrode pad 481d can be connected to the second transparent electrode 435 and the third electrode transparent 445 in common through aperture 461e. Since the semiconductor layers of the same type of conductivity of the second LED stack 433 and the third LED stack 443 are arranged facing each other, a short circuit may not occur through the common electrode pad 481d. The semiconductor layers of the second semiconductor layers of conductivity type 433b and 443b of the second LED stack 433 and the third LED stack 443 are described as facing each other, but the inventive concepts are not limited to it.
[0623] [0623] As described with reference to FIG. 51, the light-emitting devices 400 mounted on the circuit board 401 can be driven by a passive matrix method or an active matrix method.
[0624] [0624] FIG. 65 is a schematic cross-sectional view of a stack of light emitting diode (LED) lights for a display according to an exemplary embodiment.
[0625] [0625] Referring to FIG. 65, the stack of light-emitting diodes 4000 for a display can include a support substrate 4051, a first stack of LED 4023, a second stack of LED 4033, a third stack of LED 4043, a reflective electrode 4025, an ohmic electrode 4026, a first insulating layer 4027, a second insulating layer 4028, an interconnecting line 4029, a second transparent electrode p 4035, a third transparent electrode p 4045, a first color filter 4037, a second color filter 4047, a second color filter 4047, layers of hydrophilic material 4052, 4054 and 4056, a first connection layer 4053 (a lower connection layer), a second connection layer 4055 (an intermediate connection layer) and a third connection layer 4057 (an upper bonding layer).
[0626] [0626] The support substrate 4051 supports semiconductor cells 4023, 4033 and 4043. The support substrate 4051 can have a circuit on its surface or inside, but is not limited to this. The support substrate 4051 can include, for example, a glass, a sapphire substrate, a Si substrate or a Ge substrate.
[0627] [0627] The first 4023 LED battery, the second 4033 LED battery and the 4043 LED battery include the first semiconductor layers of conductivity type 4023a, 4033a and 4043a, the semiconductor layers of the second conductivity type 4023b, 4033b and 4043b and the active layers interposed between the first conductivity-type semiconductor layers and the second conductivity-type semiconductor layers. The active layer can have a multi-quantum well structure.
[0628] [0628] The first 4023 LED battery can be an inorganic LED that emits red light, the second 4033 LED battery can be an inorganic LED that emits green light and the third 4043 LED battery can be an inorganic LED that emits blue light . The first 4023 LED stack can include a GaInP based well layer, and the second 4033 LED stack and the third 4043 LED stack can include a GaInN based well layer. However, the inventive concepts are limited to them and, when the LED batteries include micro LEDs, the first 4023 LED battery can emit any red, green and blue light, and the second and third 4033 and 4043 LED batteries they can emit a different one of the red, green and blue lights without adversely affecting the operation or require color filters due to their small form factor.
[0629] [0629] The opposite surfaces of each 4023, 4033 or 4043 LED stack are a n-type semiconductor layer and a p-type semiconductor layer, respectively. The illustrated exemplary embodiment describes a case in which the first semiconductor layers of conductivity type 4023a, 4033a and 4043a of each of the first to the third LED cells 4023, 4033 and 4043 are of type n and the second semiconductor layers of conductivity type 4023b , 4033b and 4043b are of the p type. A rough surface can be formed on the upper surfaces of the first to the third 4023, 4033 and 4043 LED batteries. However, the inventive concepts are not limited to them, and the type of semiconductor types on the upper and lower surfaces of each one of the LED batteries can be reversed.
[0630] [0630] The first 4023 LED stack is arranged to be adjacent to the support substrate 4051, the second 4033 LED stack is arranged on the first 4023 LED stack and the third 4043 LED stack is arranged on the second 4033 LED stack. Since the first 4023 LED battery emits light of a wavelength greater than the wavelengths of the second and third 4033 and 4043 LED batteries, the light generated in the first 4023 LED battery can be transmitted through the second and third batteries LED 4033 and 4043 and can be sent abroad. In addition, since the second 4033 LED battery emits light of a wavelength greater than the length of the third 4043 LED battery, the light generated in the second 4033 LED battery can be transmitted through the third 4043 LED battery and can be issued abroad.
[0631] [0631] The reflecting electrode 4025 is in ohmic contact with the second conductivity type semiconductor layer of the first 4023 LED stack and reflects the light generated in the first 4023 LED stack. For example, the reflecting electrode 4025 may include a layer in ohmic contact 4025a and a reflective layer 4025b.
[0632] [0632] The ohmic contact layer 4025a is partially in contact with the second conductivity-type semiconductor layer, that is, a p-type semiconductor layer. In order to prevent the absorption of light by the ohmic contact layer 4025a, an area in which the ohmic contact layer 4025a is in contact with the p-type semiconductor layer cannot exceed about 50% of a total area of the semiconductor layer of the like p. The reflective layer 4025b covers the ohmic contact layer 4025a and also covers the first insulating layer 4027. As illustrated, the reflective layer 4025b can substantially cover the entire ohmic contact layer 4025a, or a portion of the ohmic contact layer 4025a.
[0633] [0633] The reflective layer 4025b covers the first insulating layer 4027, so that an omnidirectional reflector can be formed by a stack of the first 4023 LED stack with a relatively high refractive index and the first insulating layer 4027 and the layer reflector 4025b with a relatively low refractive index. The reflective layer 4025b covers about 50% or more of the area of the first 4023 LED stack, preferably most of the region of the first 4023 LED stack, thus improving light efficiency.
[0634] [0634] The ohmic contact layer 4025a and the reflective layer 4025b can be formed by a metal layer containing gold (Au). The ohmic contact layer 4025a can be formed, for example, by an Au-Zn alloy or an Au-Be alloy. The reflective layer 4025b can be formed by a metal layer with high reflectivity in relation to the light generated in the first 4023 LED stack, for example, red light, such as aluminum (Al), silver
[0635] [0635] The first insulating layer 4027 is disposed between the support substrate 4051 and the first 4023 LED stack and has an opening exposing the first 4023 LED stack. The ohmic contact layer 4025a is connected to the first 4023 LED stack. inside the opening of the first insulating layer 4027.
[0636] [0636] The ohmic electrode 4026 is in ohmic contact with the first semiconductor layer of conductivity type 4023a of the first layer of LED stack 4023. The ohmic electrode 4026 can be disposed in the first semiconductor layer of conductivity type 4023a partially exposed by removing the second semiconductor layer of conductivity type 4023b. Although FIG. 65 illustrates an ohmic electrode 4026, a plurality of ohmic electrodes 4026 are aligned in a plurality of regions on the support substrate 4051. The ohmic electrode 4026 can be formed, for example, by an Au-Te alloy or an Au-Ge alloy.
[0637] [0637] The second insulation layer 4028 is disposed between the supporting substrate 4051 and the reflective electrode 4025 to cover the reflective electrode 4025. The second insulation layer 4028 has an opening exposing the ohmic electrode 4026. The second insulation layer 4028 it can be formed from SiO2 or SOG.
[0638] [0638] The first interconnection line 4029 is arranged between the second insulation layer 4028 and the supporting substrate 4051, and is connected to the ohmic electro 4026 through the opening of the second insulation layer 4028. The interconnection line 4026 can connect a plurality of ohmic electrodes 4026 to each other on the support substrate 4051.
[0639] [0639] The second transparent electrode p 4035 is in ohmic contact with the second semiconductor layer of conductivity type 4033b of the second LED stack 4033, that is, the semiconductor layer of type p. The second transparent electrode p 4035 can be formed by a metal layer or a layer of conductive oxide that is transparent to red light and green light.
[0640] [0640] The third transparent electrode p 4045 is in ohmic contact with the second semiconductor layer of conductivity type 4043b of the third battery of LED 4043, that is, the semiconductor layer of type p. The third transparent electrode p 4045 can be formed by a metal layer or a layer of conductive oxide that is transparent to red light, green light and blue light.
[0641] [0641] The reflective electrode 4025, the second transparent electrode p 4035 and the third transparent electrode p 4045 can be in ohmic contact with the type p semiconductor layer of each LED cell to assist in the dispersion of the current.
[0642] [0642] The first 4037 color filter can be disposed between the first 4023 LED battery and the second 4033 LED battery. In addition, the second 4047 color filter can be disposed between the second 4033 LED battery and the third battery 4043 LED. The first 4037 color filter transmits light generated in the first 4023 LED stack and reflects the light generated in the second LED stack.
[0643] [0643] According to some exemplary modalities, the first 4037 color filter can also reflect the light generated in the third 4043 LED battery. According to some exemplary modalities, when the LED batteries include micro LEDs, the color filters can omitted due to the small form factor of the micro LEDs.
[0644] [0644] The first and second color filters 4037 and 4047 can be, for example, a low pass filter that passes through only a low frequency region, that is, a long wavelength region, a low pass filter. band that passes only through a predetermined wavelength range or a band interrupt filter that blocks only the predetermined wavelength range. In particular, the first and second color filters 4037 and 4047 can be formed by alternating stacking of insulation layers with different refractive indices and can be formed by alternating stacking, for example, TiO2 and SiO2, Ta2O5 and SiO2, Nb2O5 and SiO2, HfO2 and SiO2 or ZrO2 and SiO2. In addition, the first and / or second 4037 and / or 4047 color filters may include a distributed Bragg reflector (DBR). The distributed Bragg reflector can be formed by alternately stacking layers of insulation with different refractive indices. In addition, an interrupted band of the distributed Bragg reflector can be controlled by adjusting a thickness of TiO2 and SiO2.
[0645] [0645] The first 4053 link layer couples the first 4023 LED stack to the 4051 support substrate. As illustrated, the 4029 interconnect line can be in contact with the first 4053 link layer. In addition, the 4029 interconnect line is arranged below some regions of the second insulation layer 4028, and a region of the second insulation layer 4028 that does not have the interconnect line 4029 may be in contact with the first connection layer 4053. The first connection layer 4053 can be transmissive to light or non-transmissive to light. In particular, a contrast of the display device can be improved by using a light-absorbing adhesive layer, such as black epoxy, as the first bonding layer
[0646] [0646] The first bonding layer 4053 can be in direct contact with the support substrate 4051, but, as illustrated, the layer of hydrophilic material 4052 can be arranged at an interface between the support substrate 4051 and the first bonding layer 4053. The hydrophilic material layer 4052 can alter a surface of the support substrate 4051 to be hydrophilic to improve adhesion of the first 4053 bonding layer. As used herein, the bonding layer and the hydrophilic material layer can collectively be referred to as a buffer layer.
[0647] [0647] The first bonding layer 4053 has a strong adhesion to the layer of hydrophilic material, while it has a weak adhesion to a layer of hydrophobic material. Therefore, peeling can occur in a portion where adhesion is poor. The layer of hydrophilic material 4052, according to an exemplary embodiment, can change a hydrophobic surface to be hydrophilic to improve the adhesion of the first bonding layer 4053, thus preventing peeling from occurring.
[0648] [0648] The layer of hydrophilic material 4052 can also be formed by depositing, for example, SiO2 or others on the surface of the support substrate 4051, and can also be formed by treating the surface of the support substrate 4051 with plasma to modify the surface. The modified layer on the surface increases the energy of the surface to change the hydrophobic property to hydrophilic property. In a case where the second insulation layer 4028 has hydrophobic property, the layer of hydrophilic material can also be disposed in the second layer of insulation 4028, and the first connection layer 4052 can be in contact with the layer of hydrophilic material in the second insulation layer 4028.
[0649] [0649] The second 4055 link layer couples the second 4033 LED stack to the first 4023 LED stack. The second 4055 link layer can be arranged between the first 4023 LED stack and the first 4037 color filter and can be contact with the first 4037 color filter. The second link layer 4055 can transmit light generated in the first 4023 LED stack. A layer of hydrophilic material 4054 can be arranged at an interface between the first 4023 LED stack and the second layer of connection 4055. The first semiconductor layer of conductivity type 4023a of the first 4023 LED stack generally exhibits hydrophobic properties. Therefore, in a case where the second bonding layer 4055 is in direct contact with the first semiconductor layer of conductivity type 4023a, peeling is likely to occur at an interface between the second bonding layer 4055 and the first semiconductor layer of conductivity type 4023a.
[0650] [0650] The layer of hydrophilic material 4054, according to an exemplary embodiment, changes the surface of the first 4023 LED stack from having hydrophobic properties to having hydrophilic properties and thus improves the adhesion of the second 4055 bonding layer, thereby reducing or preventing peeling from occurring. The layer of hydrophilic material 4054 can be formed by depositing SiO2 or modifying the surface of the first 4023 LED plasma stack, as described above.
[0651] [0651] A surface layer of the first color filter 4037 which is in contact with the second layer of connection 4055 may be a layer of hydrophilic material, for example, SiO2. In a case where the surface layer of the first color filter 4037 is not hydrophilic, the layer of hydrophilic material can be formed on the first color filter 4037 and the second bonding layer 4055 can be in contact with the layer of hydrophilic material .
[0652] [0652] The third layer of connection 4057 couples the third battery of LED 4043 to the second pile of LED 4033. The third layer of connection 4057 can be arranged between the second battery of LED 4033 and the second color filter 4047 and can be in contact with the second color filter 4047. The third connection layer 4057 transmits light generated in the first battery of LED 4023 and in the second battery of LED 4033. A layer of hydrophilic material 4056 can be arranged at an interface between the second battery of LED 4033 and the third 4057 link layer. The second 4033 LED stack may exhibit hydrophobic property and, as a result, in a case where the third 4057 link layer is in direct contact with the second 4033 LED stack, it is likely that stripping occurs at an interface between the third 4057 link layer and the second 4033 LED stack.
[0653] [0653] The layer of hydrophilic material 4056, according to an exemplary modality, changes the surface of the second LED stack 4033 from hydrophobic to hydrophilic property and therefore improves the adhesion of the third layer of bond 4057, thus preventing the peeling. The layer of hydrophilic material 4056 can be formed by depositing SiO2 or modifying the surface of the second 4033 LED plasma stack as described above.
[0654] [0654] A surface layer of the second color filter 4047 which is in contact with the third layer of connection 4057 may be a layer of hydrophilic material, for example, SiO2. In a case where the surface layer of the second color filter 4047 is not hydrophilic, the layer of hydrophilic material can be formed in the second color filter 4047 and the third bonding layer 4057 can be in contact with the layer of hydrophilic material.
[0655] [0655] The first to third bonding layers 4053, 4055 and 4057 can be formed by light transmitting SOC, but are not limited to this, and other layers of transparent organic material or layers of transparent inorganic material can be used. Examples of the organic material layer can include SU8, poly (methylmethacrylate) (PMMA), polyimide, parylene, benzocyclobutene (BCB) or others, and examples of the inorganic material layer can include Al2O3, SiO2, SiNx or others. The layers of organic material can be bonded at high vacuum and high pressure, and the layers of inorganic material can be bonded by planarizing a surface with, for example, a chemical mechanical polishing process, changing the energy of the surface using plasma or others and, then using the altered surface energy method.
[0656] [0656] FIGS. 66A to 66F are schematic cross-sectional views illustrating a method of manufacturing the 4000 LED light stack for a display according to the exemplary embodiment.
[0657] [0657] Referring to FIG. 66A, a first 4023 LED stack is first grown on a first 4021 substrate. The first 4021 substrate can be, for example, a GaAs substrate. The first 4023 LED stack consists of semiconductor layers based on AlGaInP and includes a first semiconductor layer of conductivity type 4023a, an active layer and a second semiconductor layer of conductivity type 4023b.
[0658] [0658] Next, the second conductivity semiconductor layer 4023b is partially removed to expose the first conductivity semiconductor layer 4023a. Although FIG. 66A showing only one pixel region, the first semiconductor layer of conductivity type 4023a is partially exposed for each of the pixel regions.
[0659] [0659] A first 4027 insulation layer is formed on the first 4023 LED stack and is standardized to form openings. For example, SiO2 is formed on the first 4023 LED stack, a photoresistor is applied to it and a photoresistor pattern is formed through photolithography and development. Then, the first insulation layer 4027 in which the openings are formed can be formed by standardizing SiO2 using the photoresistor pattern as a recording mask. One of the openings in the first insulation layer 4027 can be arranged in the first semiconductor layer of conductivity type 4023a, and other openings can be arranged in the second semiconductor layer of conductivity type 4023b.
[0660] [0660] Thereafter, an ohmic contact layer 4025a and an ohmic electrode 4026 are formed in the openings of the first insulation layer 4027. The ohmic contact layer 4025a and the ohmic electrode 4026 can be formed using a lifting technique. The ohmic contact layer 4025a can be formed first and the ohmic electrode 4026 can be formed or vice versa. In addition, according to an exemplary embodiment, the ohmic electrode 4026 and the ohmic contact layer 4025a can be formed simultaneously from the same material layer.
[0661] [0661] After the formation of the ohmic contact layer 4025a, a reflective layer 4025b covering the ohmic contact layer 4025a and the first insulation layer 4027 is formed. The reflective layer 4025b can be formed using a lifting technique. The reflective layer 4025b can also cover a portion of the ohmic contact layer 4025a and can also substantially cover the entire ohmic contact layer 4025a, as illustrated. A reflective electrode 4025 is formed by the ohmic contact layer 4025a and the reflective layer 4025b.
[0662] [0662] The reflecting electrode 4025 may be in ohmic contact with a p-type semiconductor layer of the first 4023 LED stack and may thus be referred to as a first reflecting electrode of the type p 4025. The reflecting electrode 4025 is spaced from the ohmic electrode 4026 and therefore is electrically isolated from the first semiconductor layer of conductivity type 4023a.
[0663] [0663] A second insulation layer 4028 covering the reflective electrode 4025 and having an opening exposing the ohmic electrode 4026 is formed. The second insulation layer 4028 can be formed from, for example, SiO2 or SOG.
[0664] [0664] Then, an interconnection line 4029 is formed in the second insulation layer 4028. Interconnection line 4029 is connected to the ohmic electrode 4026 through the opening of the second insulation layer 4028 and therefore is electrically connected to the first semiconductor layer. 4023a of the conductivity type.
[0665] [0665] Although the 4029 interconnect line is illustrated in FIG. 66A as covering the entire surface of the second insulation layer 4028, the interconnect line 4029 can be partially arranged in the second insulation layer 4028, and an upper surface of the second insulation layer 4028 can be exposed around the interconnect line 4029.
[0666] [0666] Although the exemplary embodiment illustrated shows a pixel region, the first 4023 LED stack disposed on substrate 4021 can cover a plurality of pixel regions and interconnect line 4029 can normally be connected to ohmic electrodes 4026 formed in a plurality of regions. In addition, a plurality of interconnect lines 4029 can be formed on substrate 4021.
[0667] [0667] Referring to FIG. 66B, a second 4033 LED stack is grown on a second 4031 substrate and a second transparent p 4035 electrode and a first 4037 color filter are formed on the second 4033 LED stack. The second 4033 LED stack can include a first semiconductor layer conductivity type 4033a based on gallium nitride, a second semiconductor layer conductivity type 4033b and an active layer disposed between them, and the active layer can include a GaInN well layer. The second substrate 4031 is a substrate on which a semiconductor layer based on gallium nitride can be grown and is different from the first substrate 4021. A combination ratio of GaInN can be determined so that the second 4033 LED stack can emit green light . The second transparent electrode p 4035 is in ohmic contact with the second semiconductor layer of conductivity type 4033b.
[0668] [0668] The first color filter 4037 can be formed on the second transparent electrode p-4035, and since its details are substantially the same as those described with reference to FIG. 65, its detailed descriptions will be omitted to avoid redundancy.
[0669] [0669] Referring to FIG. 66C, a third 4043 LED stack is grown on a third 4041 substrate and a third transparent 4045 electrode and a second 4047 color filter are formed on the third 4043 LED stack. The third 4043 LED stack can include a first semiconductor layer Conductivity type 4043a based on gallium nitride, a second semiconductor layer of conductivity type 4043b and an active layer disposed between them, and the active layer can include a GaInN well layer. The third 4041 substrate is a substrate on which a semiconductor layer based on gallium nitride can be grown and is different from the first 4021 substrate. A combination ratio of GaInN can be determined so that the third 4043 LED stack emits blue light . The third transparent electrode 4045 is in ohmic contact with the second semiconductor layer of conductivity type 4043b.
[0670] [0670] Since the second color filter 4047 is substantially the same as that described with reference to FIG. 65, its detailed descriptions will be omitted to avoid redundancy.
[0671] [0671] Meanwhile, since the first 4023 LED battery, the second 4033 LED battery and the third 4043 LED battery are grown on different substrates, their order of formation is not particularly limited.
[0672] [0672] Referring to FIG. 66D, the first 4023 LED stack is then coupled to a support substrate 4051 through the first bonding layer 4053. The layers of bonding material can be arranged on the support substrate 4051 and the second insulation layer 4028 and can be connected together to form the first 4053 bonding layer. The interconnect line 4029 is arranged to face the supporting substrate
[0673] [0673] Meanwhile, in a case where a surface of the support substrate 4051 has hydrophobic property, a layer of hydrophilic material 4052 can be formed first on the support substrate 4051. The layer of hydrophilic material 4052 can also be formed by depositing a layer of material such as SiO2 on the surface of the support substrate 4051, or by treating the surface of the support substrate 4051 with plasma or the like to increase surface energy. The surface of the support substrate 4051 is modified by plasma treatment, and a modified surface layer with high surface energy can be formed on the surface of the support substrate 4051. The first bonding layer 4053 can be bonded to the layer of hydrophilic material 4052 , and the adhesion of the first bonding layer 4053 is thus improved.
[0674] [0674] The first 4021 substrate is removed from the first 4023 LED stack using a chemical etching technique. Therefore, the first conductivity type semiconductor layer of the first 4023 LED stack is exposed on the top surface. The exposed surface of the first semiconductor layer of conductivity type 4023a can be textured to increase the efficiency of light extraction, and a light extraction structure, such as a rough or other surface, can thus be formed on the surface of the first semiconductor layer of conductivity. conductivity type 4023a.
[0675] [0675] Referring to FIG. 66E, the second 4033 LED stack is coupled to the first 4023 LED stack via the second 4055 link layer. The first 4037 color filter is arranged to face the first 4023 LED stack and is connected to the second 4055 link layer. The layers of bonding material are arranged in the first 4023 LED stack and the 4037 first color filter and are bonded together to form the second bonding layer
[0676] [0676] Meanwhile, before the second link layer 4055 is formed, a layer of hydrophilic material 4054 can be formed first on the first 4023 LED stack. The layer of hydrophilic material 4054 changes the surface of the first 4023 LED stack to from the hydrophobic property to the hydrophilic property and thus improves the adhesion of the second bonding layer 4055. The layer of hydrophilic material 4054 can also be formed by depositing a layer of material like SiO2 or treating the surface of the first 4023 LED stack with plasma or others to increase the energy of the surface. The surface of the first 4023 LED stack is modified by plasma treatment, and a modified surface layer with high surface energy can be formed on the surface of the first 4023 LED stack. The second 4055 bonding layer can be bonded to the material layer hydrophilic 4054, and the adhesion of the second bonding layer 4055 is thus improved.
[0677] [0677] The second 4031 substrate can be separated from the second 4033 LED stack using a technique such as a laser lift or a chemical lift. In addition, in order to improve light extraction, a rough surface can be formed on the exposed surface of the first semiconductor layer of conductivity type 4033a using surface texturing.
[0678] [0678] Referring to FIG. 66F, a layer of hydrophilic material 4056 can be formed on the second stack of LED 4033. The layer of hydrophilic material 4056 changes the surface of the second stack of LED 4033 to hydrophilic property and thus improves the adhesion of the third layer of connection 4057. The 4056 hydrophilic material layer can also be formed by depositing a material layer like SiO2 or treating the surface of the second 4033 LED stack with plasma or the like to increase the surface energy. However, in a case where the surface of the second 4033 LED stack has hydrophilic property, the layer of hydrophilic material 4056 can be omitted.
[0679] [0679] Next, with reference to FIGS. 65 and 66C, the third battery of LED 4043 is coupled to the second battery of LED 4033 through the third layer of connection 4057. The second color filter 4047 is arranged to face the second battery of LED 4033 and is connected to the third layer of connection 4057. The layers of bonding material are arranged in the second LED stack 4033 (or in the hydrophilic material layer 4056) and in the third color filter 4047, and are bonded together to form the third bonding layer 4057.
[0680] [0680] The third 4041 substrate can be separated from the third 4043 LED stack using a technique such as a laser lift or a chemical lift. Therefore, as illustrated in FIG. 65, the LED stack for a display to which the first conductive layer 4043a of the third 4043 LED stack is exposed is provided. In addition, a rough surface can be formed on the exposed surface of the first semiconductor layer of conductivity type 4043a by texturing the surface.
[0681] [0681] A battery from the first to the third LED batteries 4023, 4033 and 4043 arranged on the support substrate 4051 is standardized in a pixel unit, and the standardized batteries are connected to each other using the interconnect lines, thus making it possible to provide a display device. In the following, a display device according to exemplary modalities will be described.
[0682] [0682] FIG. 67 is a schematic circuit diagram of a display apparatus according to an exemplary embodiment, and FIG. 68 is a schematic plan view of a display apparatus according to an exemplary embodiment.
[0683] [0683] Referring to FIGS. 67 and 68, the display apparatus according to an exemplary modality can be implemented to be operated in a passive way.
[0684] [0684] For example, since the LED stack for a display is described with reference to FIG. 65 has a structure in which the first to the third LED batteries 4023, 4033 and 4044 are stacked in a vertical direction, one pixel including three light-emitting diodes R, G and B. Here, a first LED R can match to the first 4023 LED battery, a second LED light G can correspond to the second 4033 LED battery and a third LED light B can correspond to the third 4043 LED battery.
[0685] [0685] In FIGS. 67 and 68, a pixel includes the first to third light-emitting diodes R, G and B, and each light-emitting diode corresponds to a sub-pixel. The anodes of the first to the third light-emitting diodes R, G and B are connected to a common line, for example, a data line and their cathodes are connected to different lines, for example, scanning lines. For a first pixel, as an example, the anodes from the first to the third light-emitting diodes R, G and B are commonly connected to a Vdata1 data line and their cathodes are connected to the Vscan1-1, Vscan1-2 scan lines , and Vscan1-3, respectively. Therefore, the light emitting diodes R, G and B in the same pixel can be activated separately.
[0686] [0686] In addition, each of the light emitting diodes R, G and B can be activated by modulating the pulse width or changing the current intensity, thus making it possible to adjust the brightness of each subpixel.
[0687] [0687] Referring again to FIG. 68, a plurality of patterns are formed by patterning the stacks described with reference to FIG. 65, and the respective pixels are connected to the reflecting electrodes 4025 and to the interconnecting lines 4071, 4073 and 4075. As illustrated in FIG. 67, the reflective electrode 4025 can be used as a Vdata data line and the interconnect lines 4071, 4073 and 4075 can be formed as the scan lines. Here, interconnect line 4075 can be formed by interconnect line 4029. Reflective electrode 4025 can electrically connect the first semiconductor layers of conductivity type 4023a, 4033a and 4043a from the first to the third 4023, 4033 and 4043 LED batteries of the plurality of pixels to each other, and the interconnect line 4029 can be arranged as being substantially perpendicular to the reflective electrode 4025 to electrically connect the first semiconductor layers of conductivity type 4023a of the plurality of pixels to each other.
[0688] [0688] The pixels can be arranged in a matrix form, and the anodes of the light-emitting diodes R, G and B of each pixel are commonly connected to the reflective electrode 4025 and their cathodes are connected to the interconnection lines 4071, 4073 , and 4075 that are spaced from each other. Here, interconnect lines 4071, 4073 and 4075 can be used as Vscan scan lines.
[0689] [0689] FIG. 69 is an enlarged one-pixel plan view of the display apparatus of FIG. 68, FIG. 70 is a schematic cross-sectional view taken along a line A-A of FIG. 69, and FIG. 71 is a schematic cross-sectional view taken along a line B-B of FIG. 69.
[0690] [0690] Referring back to FIGS. 68 to 71, at each pixel, a portion of the reflective electrode 4025, a portion of the second transparent electrode p 4035, a portion of the upper surface of the second LED battery 4033, a portion of the third transparent electrode p 4045 and the upper surface of the third 4043 LED stack are exposed to the outside.
[0691] [0691] The third 4043 LED stack may have a 4043r rough surface formed on its upper surface. The rough surface 4043r can also be formed on the entire upper surface of the third 4043 LED stack, or on a portion of the upper surface of the third 4043 LED stack.
[0692] [0692] A lower layer of insulation 4061 can cover a side surface of each pixel. The lower insulation layer 4061 can be formed of a light transmitting material, such as SiO2, and in this case, the lower insulation layer 4061 can also substantially cover the entire upper surface of the third 4043 LED stack. Alternatively, the layer 4061 bottom insulation, according to an exemplary embodiment, may include a light-reflecting layer or a light-absorbing layer to prevent light from traveling from the first to the third 4023, 4033 and 4043 LED batteries to the side surface and, in this case, the bottom insulation layer 4061 exposes at least partially the top surface of the third 4043 LED stack. The bottom insulation layer 4061 may include, for example, a distribution Bragg reflector or a metallic reflective layer, or a layer organic reflector in a transparent insulation layer, and can also include a light absorbing layer, such as black epoxy. The light-absorbing layer, such as black epoxy, can prevent light from being emitted to the outside of the pixels, thereby improving a contrast ratio between the pixels on the display device.
[0693] [0693] The bottom insulation layer 4061 can have an opening 4061a exposing the top surface of the third LED battery 4043, an opening 4061b exposing the top surface of the second LED battery 4033, an opening 4061c exposing the third transparent electrode p 4045, an opening 4061d and exposing the second transparent electrode p 4035 and an opening 4061e exposing the first reflective electrode of type p 4025. The top surface of the first LED battery 4023 cannot be exposed to the outside.
[0694] [0694] The interconnect line 4071 and the interconnect line 4073 can be formed on the support substrate 4051 in the vicinity of the first to the third LED cells 4023, 4033 and 4043, and can be arranged in the bottom insulation layer 4061 to be isolated of the first reflective electrode of type p 4025. A connector 4077ab connects the second transparent electrode p 4035 and the third transparent electrode 4045 to the reflective electrode 4025. Therefore, the anodes of the first 4023 LED battery, the second 4033 LED battery and the third 4043 LED stack are commonly connected to the reflective electrode
[0695] [0695] The interconnection line 4075 or 4029 can be arranged to be substantially perpendicular to the reflecting electrode 4025 below the reflecting electrode 4025 and is connected to the ohmic electrode 4026, thus being electrically connected to the first conductivity type 4023a semiconductor layer. The ohmic electrode 4026 is connected to the first semiconductor layer of conductivity type 4023a below the first LED stack
[0696] [0696] The 4071a connector connects the top surface of the third 4043 LED stack to the 4071 interconnect line and the 4073a connector connects the top surface of the second 4033 LED stack to the 4073 interconnect line.
[0697] [0697] An upper insulation layer 4081 can be arranged on interconnect lines 4071 and 4073 and the lower insulation layer 4061 to protect interconnect lines 4071, 4073 and 4075. The upper insulation layer 4081 can have openings that expose the interconnect lines 4071, 4073 and 4075, and a connecting wire and the like can be connected to it through the openings.
[0698] [0698] According to an exemplary modality, the anodes from the first to the third LED batteries 4023, 4033 and 4043 are commonly and electrically connected to the reflective electrode 4025, and their cathodes are electrically connected to the interconnection lines 4071, 4073 and 4075 , respectively. Therefore, the first to third LED batteries 4023, 4033 and 4043 can be driven independently. However, inventive concepts are not limited to them, and electrode and wiring connections can be modified in a number of ways.
[0699] [0699] FIGS. 72A to 72H are schematic views of the plan to describe a method for manufacturing a display device according to an exemplary embodiment. Next, a method for making the pixel of FIG. 69 will be described.
[0700] [0700] First, the stack of light-emitting diodes 4000, as described with reference to FIG. 65 is prepared.
[0701] [0701] Next, with reference to FIG. 72A, the rough surface 4043r can be formed on the top surface of the third 4043 LED stack. The rough surface 4043r can be formed to match each pixel region on the top surface of the third 4043 LED stack. The rough surface 4043r can be formed. by a chemical engraving technique, for example, by a photo-enhanced chemical engraving technique (PEC).
[0702] [0702] The rough surface 4043r can be partially formed within each pixel region in consideration of a region in which the third 4043 LED stack is to be engraved in the future. In particular, the rough surface 4043r can be formed so that the ohmic electrode 4026 is disposed outside the rough surface 4043r. However, the inventive concepts are limited to these, and the rough surface 4043r can also be formed over substantially the entire upper surface of the third 4043 LED stack.
[0703] [0703] Referring to FIG. 72B, a peripheral region of the third 4043 LED cell is then etched into each pixel region to expose the third transparent electrode p 4045. The third 4043 LED cell can have a substantially rectangular or square shape, as illustrated, but at least two depression parts can be formed along the edges. In addition, as illustrated, a part of the depression can be formed to be larger than another part of the depression.
[0704] [0704] Referring to FIG. 72C, the exposed third transparent electrode p 4045 is then removed, except for a portion of the third transparent electrode p 4045 exposed in a relatively large depression portion, to thereby expose the upper surface of the second 4033 LED stack. The upper surface of the second 4033 LED stack is exposed around the third 4043 LED stack and is also exposed in another part of the depression. A region in which the third transparent electrode p 4045 is exposed and a region in which the second battery of LED 4033 is exposed are formed in the relatively large depression part.
[0705] [0705] Referring to FIG. 72D, the second battery of LED 4033 exposed in the remaining region is removed, except the second battery of LED 4033 formed in a relatively small depression part to expose the second transparent electrode p 4035. The second transparent electrode p is exposed around the third battery of LED 4043 and the second transparent electrode p 4035 are also exposed in the relatively large depression part.
[0706] [0706] Referring to FIG. 72E, the second transparent electrode p 4035 exposed around the second battery of LED 4043 is then removed, except for the second transparent electrode p 4035 exposed in the relatively large depression part, to thereby expose the upper surface of the first battery of LED 4023.
[0707] [0707] Referring to FIG. 72F, the first 4023 LED battery exposed around the third 4043 LED battery continues to be removed and the first insulation layer 4027 is removed to thereby expose the reflective electrode 4025. Consequently, the reflective electrode 4025 is exposed around the third 4043 LED stack. The exposed reflective electrode 4025 is standardized so that it is substantially elongated in the vertical direction to form a linear interconnect line. The standardized reflective electrode 4025 is arranged over the plurality of pixel regions in the vertical direction and is spaced from a neighboring pixel in the horizontal direction.
[0708] [0708] In the exemplary example illustrated, it is described that the reflective electrode 4025 is standardized after the first stack of LED 4023 is lifted, but the reflective electrode 4025 can also be formed in advance to have the standardized shape when the reflective electrode 4025 is formed in the substrate 4021. In this case, it is not necessary to standardize the reflective electrode 4025 after removing the first 4023 LED battery.
[0709] [0709] When standardizing the reflective electrode 4025, the second insulation layer 4028 can be exposed. The interconnect line 4029 is arranged to be perpendicular to the reflective electrode 4025 and is isolated from the reflective electrode 4025 by the second insulation layer 4028.
[0710] [0710] Referring to FIG. 72G, the bottom insulating layer 4061 (FIGS. 70 and 71) covering the pixels is then formed. The lower insulation layer 4061 covers the reflective electrode 4025 and covers the side surfaces of the first to the third LED batteries 4023, 4033 and 4043. In addition, the lower insulation layer 4061 can at least partially cover the upper surface of the third battery. LED 4043. In a case where the bottom insulation layer 4061 is a transparent layer like SiO2, the bottom insulation layer 4061 can also substantially cover the entire upper surface of the third 4043 LED stack. Alternatively, the bottom insulation layer 4061 may also include a reflective layer or a light absorbing layer, in which case the lower insulating layer 4061 exposes at least partially the upper surface of the third 4043 LED stack, so that the light is emitted to the outside.
[0711] [0711] The bottom insulating layer 4061 can have an opening 4061a exposing the third stack of LED 4043, an opening 4061b exposing the second stack of LED 4033, an opening 4061c exposing the third transparent electrode p 4045, an opening 4061d exposing the second transparent electrode p 4035 and an opening 4061e exposing the reflective electrode 4025. One or more openings 4061e that expose the reflective electrode 4025 can be formed.
[0712] [0712] Referring to FIG. 72H, interconnection lines 4071 and 4073 and connectors 4071a, 4073a and 77ab are then formed by a lifting technique. Interconnect lines 4071 and 4073 are isolated from reflective electrode 4025 by the bottom insulation layer 4061. Connector 4071a electrically connects the third 4043 LED stack to the 4071 interconnect line and connector 4073a connects the second 4033 LED stack to the interconnection 4073. Connector 77ab electrically connects the third transparent electrode p 4045 and the second transparent electrode p 4035 to the first reflective electrode of type p 4025.
[0713] [0713] The interconnection lines 4071 and 4073 can be arranged to be substantially perpendicular to the reflective electrode 4025 and can connect the plurality of pixels to each other.
[0714] [0714] Then, the upper insulating layer 4081 (FIGS. 70 and 71) covers the interconnection lines 4071 and 4073 and the connectors 4071a, 4073a and 4077ab. The upper insulating layer 4081 can also substantially cover the entire upper surface of the third 4043 LED stack. The upper insulating layer 4081 can be formed, for example, of silicon oxide film or silicon nitride film, and also can include a distribution Bragg reflector. In addition, the top insulating layer 4081 may include a transparent insulating film and a reflective metal layer, or an organic reflective layer of a multilayer structure on top of it to reflect light, or it may include a light absorbing layer , as a black-based epoxy to protect the light.
[0715] [0715] In a case where the upper insulating layer 4081 reflects or protects the light, to emit light to the outside, it is necessary to expose at least partially the upper surface of the third 4043 LED stack. In the meantime, to allow a connection electrical on the outside, the upper insulation layer 4081 is partially removed to thereby partially expose the interconnect lines 4071, 4073 and 4075. In addition, the upper insulation layer 4081 can also be omitted.
[0716] [0716] As the upper insulating layer 4081 is formed, the pixel region illustrated in FIG. 69 is completed. In addition, as shown in FIG. 68, the plurality of pixels can be formed on the support substrate 4051, and these pixels can be connected to each other by the first reflective electrode of type p 4025 and by the interconnecting lines 4071, 4073 and 4075, and can be activated in a matrix passive.
[0717] [0717] In the exemplary example illustrated, the method for making the display apparatus that can be operated in the passive matrix manner is described, but the inventive concepts are not limited to these, and a display apparatus including the stack of light emitting diodes light illustrated in FIG. 65 can be configured to be triggered in several ways.
[0718] [0718] For example, it is described that interconnect lines 4071 and 4073 are formed together in the lower insulation layer 4061, but interconnect line 4071 can be formed in the lower insulation layer 4061 and interconnect line 4073 can also be formed. formed in the upper insulating layer layer 4081.
[0719] [0719] Meanwhile, in FIG. 65, it is described that the reflective electrode 4025, the second transparent electrode p 4035 and the third transparent electrode p 4045 are in ohmic contact with the second semiconductor layers of conductivity type 4023b, 4033b and 4043b of the first 4023 LED stack, the second LED battery 4033 and the third LED battery 4043, respectively, and the ohmic electrode 4026 is described in ohmic contact with the first semiconductor layer of conductivity type 4023a of the first LED battery 4023, but the ohmic contact layer does not. is supplied separately for the first semiconductor layers of conductivity type 4033a and 4033b of the second LED battery 4033 and the third LED battery
[0720] [0720] According to exemplary modalities, the plurality of pixels can be formed at a wafer level using the stack of light-emitting diodes 4000 for a display and, therefore, the individual assembly steps of the light-emitting diodes can be avoided . In addition, since the light emitting diode stack has a structure that the first to third 4023, 4033 and 4043 LED batteries are stacked vertically, an area of the subpixel can be protected within a limited pixel area. In addition, as the light generated in the first 4023 LED battery, the second 4033 LED battery and the third 4043 LED battery is transmitted through these LED batteries and emitted to the outside, it is possible to reduce light loss.
[0721] [0721] However, the inventive concepts are not limited to these, and light-emitting devices can also be provided in which the respective pixels are separated, and these light-emitting devices are individually mounted on a circuit board, thus making it possible to supply the display device.
[0722] [0722] Furthermore, it is described that the ohmic electrode 4026 is formed in the first semiconductor layer of conductivity type 4023a adjacent to the second semiconductor layer of conductivity type 4023b, but the ohmic electrode 4026 can also be formed on the surface of the first semiconductor layer conductivity type 4023a opposite the second semiconductor layer of conductivity type 4023b. In this case, the third 4043 LED battery and the second 4033 LED battery are standardized to expose the 4026 ohmic electrode and, instead of the 4029 interconnect line, a separate interconnect line is provided that connects the 4026 ohmic electrode to the circuit.
[0723] [0723] FIG. 73 is a cross-sectional view of a stacked light-emitting structure, according to an exemplary embodiment.
[0724] [0724] Referring to FIG. 73, a stacked light-emitting structure, according to an exemplary embodiment, includes a plurality of sequentially stacked epitaxial cells. A plurality of epitaxial cells are provided on substrate 5010.
[0725] [0725] Substrate 5010 is substantially plate-shaped having an upper surface and a lower surface.
[0726] [0726] A plurality of epitaxial cells can be mounted on the top surface of substrate 5010, and substrate 5010 can be provided in a variety of ways. The substrate 5010 can be formed of an insulating material. Examples of the 5010 substrate material include glass, quartz, silicon, organic polymer, organic / inorganic composite or others. However, the material of the substrate 5010 is not limited to it and is not particularly limited as long as it has an insulating property. In an exemplary embodiment, the substrate 5010 can also include a piece of wiring that can provide a light-emitting signal and a common voltage for the respective epitaxial cells. In an exemplary embodiment, in addition to the spinning piece, substrate 5010 may also include a drive element including a thin film transistor, in which case the respective epitaxial cells can be driven in the type of active matrix. For this purpose, substrate 5010 can be supplied as a printed circuit board 5010 or as a composite substrate with a spinning piece and / or a driving element formed of glass, silicon, quartz, organic polymer or organic / inorganic composite.
[0727] [0727] A plurality of epitaxial cells are stacked sequentially on an upper surface of the substrate 5010 and emit light respectively.
[0728] [0728] In an exemplary embodiment, two or more epitaxial cells can be provided, each emitting light of different wavelength bands from one another. That is, a plurality of epitaxial cells can be supplied, respectively, having different energy bands from each other. In an exemplary embodiment, the epitaxial cell on substrate 5010 is illustrated as being provided with three layers stacked sequentially, including the first to third epitaxial cells 5020, 5030 and 5040.
[0729] [0729] Each of the epitaxial cells can emit colored light from a visible light strip of several wavelength bands. The light emitted by the lowest epitaxial cell is colored light of the longest wavelength with the smallest energy range, and the wavelength of the colored light emitted is shorter in the order from the bottom to the top. The light emitted by the epitaxial cell at the top is colored light with the shortest wavelength and the largest energy range. For example, the first epitaxial cell 5020 can emit the first colored light L1, the second epitaxial cell 5030 can emit the second colored light L2 and the third epitaxial cell 5040 can emit the third colored light L3. The first to third colored lights L1, L2 and L3 correspond to a different colored light from each other, and the first to the third colored lights L1, L2 and L3 can be colored lights of different wavelength ranges from each other that have lengths waveforms that decrease sequentially. That is, the first to third colored lights L1, L2 and L3 can have different wavelength ranges from one another and the colored light can be a shorter wavelength range of higher energy, in the order of the first light colored L1 to third colored light L3. However, inventive concepts are not limited to these, and when the stacked light-emitting structure includes micro LEDs, the lower epitaxial cell can emit colored light with any energy range, and the epitaxial cells arranged in it can emit a colored light having a different energy band than the lower epitaxial cell due to the small form factor of the micro LEDs.
[0730] [0730] In the exemplary mode, the first colored light L1 can be red light, the second colored light L2 can be green light and the third colored light L3 can be blue light, for example.
[0731] [0731] Each of the epitaxial cells emits light towards a frontal direction of the 5010 substrate. In particular, the light emitted by one epitaxial cell is passed through another epitaxial cell located in the light path and travels in the frontal direction. The frontal direction can correspond to a direction along which the first to third epitaxial cells 5020, 5030 and 5040 are stacked.
[0732] [0732] From now on, in addition to the front and rear directions mentioned above, the "front" direction of the 5010 substrate will be called the "top" direction and the "rear" direction of the 5010 substrate will be called the "bottom" direction. Obviously,
[0733] [0733] Each of the epitaxial cells emits light in the upper direction, and each of the epitaxial cells transmits most of the light emitted by the underlying epitaxial cells. In particular, the light emitted from the first epitaxial cell 5020 passes through the second epitaxial cell 5030 and the third epitaxial cell 5040 and travels to the front direction, and the light emitted from the second epitaxial cell 5030 passes through the third epitaxial cell 5030 and travels for the front direction. To this end, at least some, or desirably, all epitaxial cells other than the lower epitaxial cell may include an optically transmissive material. As used herein, the material being "optically transmissive" not only includes a transparent material that transmits all light, but also a material that transmits light with a predetermined wavelength or transmits a portion of light with a predetermined wavelength. In an exemplary embodiment, each epitaxial cell can transmit about 60% or more of the light emitted from the epitaxial cell disposed in it, or about 80% or more, in another exemplary mode, or about 90% or more in yet another exemplary modality.
[0734] [0734] In the light-emitting stacked structure, according to an exemplary embodiment, the signal lines for applying emitting signals to the respective epitaxial cells are connected independently and, therefore, the respective epitaxial cells can be activated independently and the stacked structure emitting light can implement several colors, according to whether light is emitted from each of the epitaxial cells. Besides that,
[0735] [0735] FIGS. 74A and 74B are seen in cross-section illustrating a stacked light-emitting structure according to an exemplary embodiment.
[0736] [0736] Referring to FIG. 74A, in a stacked light-emitting structure, according to an exemplary embodiment, each of the first to third epitaxial cells 5020, 5030 and 5040 can be supplied on a 5010 substrate via an adhesive layer or a buffer layer interposed between them.
[0737] [0737] Adhesive layer 5061 adheres to substrate 5010 and first epitaxial stack 5020 to substrate 5010. Adhesive layer 5061 can include a conductive or non-conductive material. The adhesive layer 5061 can have conductivity in some areas, when it needs to be electrically connected to the substrate 5010 provided below. The adhesive layer 5061 can include a transparent or opaque material. In an exemplary embodiment, when substrate 5010 is provided with an opaque material and has a spinning part or the like formed therein, the adhesive layer 5061 may include an opaque material, for example, a light-absorbing material. For the light-absorbing material that forms the 5061 adhesive layer, several polymeric adhesives can be used, including, for example, an epoxy-based polymeric adhesive.
[0738] [0738] The buffer layer acts as a component to adhere two layers adjacent to each other, while also serving to relieve stress or impact between two adjacent layers. The buffer layer is provided between two adjacent epitaxial cells to adhere the two adjacent epitaxial cells together, while also serving to relieve stress or impact that can affect the two adjacent epitaxial cells.
[0739] [0739] The buffer layer includes the first and second layers 5063 and 5065. The first buffer layer 5063 can be provided between the first and second epitaxial cells 5020 and 5030, and a second buffer layer 5065 can be provided between the second and the third epitaxial cells 5030 and 5040.
[0740] [0740] The buffer layer includes a material capable of relieving stress or impact, for example, a material which is capable of absorbing stress or impact when there is stress or impact on the outside. The buffer layer may have a certain elasticity for this purpose. The buffer layer can also include a material having an adhesive force. In addition, the first and second buffer layers 5063 and 5065 can include a non-conductive material and an optically transmitting material. For example, an optically clear adhesive can be used for the first and second layers of buffer 5063 and 5065.
[0741] [0741] The material to form the first and second layers of buffer 5063 and 5065 is not particularly limited as long as it is optically transparent and is able to cushion stress or impact by connecting each of the epitaxial cells in a stable manner. For example, the first and second layers of buffer 5063 and 5065 can be formed from an organic material, including an epoxy-based polymer, such as SU-8, various strengths, parylene, poly (methyl methacrylate) (PMMA), benzocyclocyclobutene (BCB), spin-on glass (SOG), or others, and inorganic material, such as silicon oxide, aluminum oxide or similar. If necessary, a conductive oxide can also be used as a buffer layer, in which case the conductive oxide must be isolated from other components. When an organic material is used as a buffer layer, the organic material can be applied to the adhesive surface and then glued at a high temperature and high pressure in a vacuum state. When an inorganic material is used as a buffer layer, the inorganic material can be deposited on the adhesive surface and then planarized by chemical-mechanical planarization (CMP) or similar, after which the surface is subjected to plasma treatment and then bonded under high vacuum.
[0742] [0742] Referring to FIG. 74B, each of the first and second layers of buffer 5063 and 5065 may include an adhesion enhancement layer 5063a or 5065a to adhere two epitaxial cells adjacent to each other and a shock absorbing layer 5063b or 5065b to relieve stress or impact between the two adjacent epitaxial cells.
[0743] [0743] The shock-absorbing layer 5063b and 5065b between two adjacent epitaxial cells plays a role in absorbing stress or impact when at least one of the two adjacent epitaxial cells is exposed to stress or impact.
[0744] [0744] The material that forms the shock-absorbing layer 5063b and 5065b may include, but is not limited to, silicon oxide, silicon nitride, aluminum oxide or others. In an exemplary embodiment, the shock-absorbing layer 5063b and 5065b can include silicon oxide.
[0745] [0745] In an exemplary embodiment, in addition to voltage or impact absorption, the shock absorbing layer 5063b and 5065b may have a predetermined adhesion force to adhere to two adjacent epitaxial cells. In particular, the shock-absorbing layer 5063b and 5065b can include a material with surface energy similar to or equivalent to the surface energy of the epitaxial cell to facilitate adhesion to the epitaxial cell. For example, when the surface of the epitaxial cell is hydrophilicized through plasma or other treatment, a hydrophilic material, such as silicon oxide, can be used as the shock absorbing layer in order to improve adhesion to the hydrophilic epitaxial cell.
[0746] [0746] Layer 5063a or 5065a to improve adhesion serves to firmly adhere two adjacent epitaxial cells. Examples of the material to form the 5063a or 5065a layer to improve adhesion include, but are not limited to, epoxy based polymers such as SOG, SU-8, various strengths, parylene, poly (methyl methacrylate) (PMMA), benzocyclocyclobene (BCB) or others. In an exemplary embodiment, the adhesion enhancement layer 5063a or 5065a may include SOG.
[0747] [0747] In an exemplary embodiment, the first buffer layer 5063 may include a first layer 5063a for improving adhesion and a first layer 5063b of shock absorption, and the second layer 5065b of damping and the second layer of buffer 5065b may include a second adhesion enhancing layer 5065a and a second shock absorbing layer 5065b. In an exemplary embodiment, each adhesion enhancement layer and the shock absorption layer can be provided as a layer, but are not limited to it, and in another exemplary embodiment, each adhesion enhancement layer and the absorption layer. shock can be provided as a plurality of layers.
[0748] [0748] In an exemplary embodiment, the stacking order of the adhesion improvement layer and the shock absorption layer can be changed in several ways. For example, the shock absorbing layer can be stacked on the adhesion enhancement layer or, conversely, the adhesion improvement layer can be stacked on the shock absorbing layer. In addition, the stacking order of the adhesion enhancing layer and the shock absorbing layer in the first buffer layer 5063 and in the second buffer layer 5065 may be different. For example, in the first buffer layer 5063, the first shock-absorbing layer 5063b and the first adhesion enhancement layer 5063a can be stacked sequentially, while in the second buffer layer 5065, the first adhesion enhancement layer 5065a and the second layer shock absorbers 5065b can be stacked sequentially. FIG. 74B shows an exemplary embodiment in which the first shock-absorbing layer 5063b is stacked in the first adhesion enhancement layer 5063a in the first buffer layer 5063, and the second shock-absorbing layer 5065b is stacked in the second shock-absorbing layer 5065a in the second layer of buffer 5065.
[0749] [0749] In an exemplary embodiment, the thicknesses of the first buffer layer 5063 and the second buffer layer 5065 may be substantially the same or different from each other. The thickness of the first buffer layer 5063 and the second buffer layer 5065 can be determined in consideration of the amount of impact on the epitaxial cells in the process of stacking the epitaxial cells. In an exemplary embodiment, the thickness of the first buffer layer 5063 may be greater than the thickness of the second buffer layer 5065. In particular, the thickness of the first shock-absorbing layer 5063b in the first layer of buffer 5063 may be greater than the thickness of the second shock absorber layer 5065b in the second layer of buffer 5065.
[0750] [0750] The stacked light-emitting structure, according to an exemplary embodiment, can be manufactured through a process in which the first to third epitaxial cells 5020, 5030 and 5040 are stacked sequentially and, consequently, the second epitaxial cell 5030 is stacked after the first epitaxial cell 5020 is stacked and the third epitaxial cell 5040 is stacked after the first and second epitaxial cells 5020 and 5030 are stacked. Therefore, the amount of voltage or impact that can be applied to the first 5020 epitaxial cell during a process is greater than the amount of voltage or impact that can be applied to the second 5030 epitaxial cell and at an increased frequency. In particular, since the second epitaxial cell 5030 is stacked in a state where the cell is shallow in thickness, the second epitaxial cell 5030 is subjected to a greater amount of voltage or impact than the voltage or impact exerted on the third cell epitaxial 5040 which is stacked on the underlying pile of relatively greater thickness. In an exemplary embodiment, the thickness of the first buffer layer 5063 is greater than the thickness of the second buffer layer 5065 to compensate for the voltage or impact difference mentioned above.
[0751] [0751] FIG. 75 is a cross-sectional view of a stacked light-emitting structure, according to an exemplary embodiment.
[0752] [0752] Referring to FIG. 75, each of the first to third epitaxial cells 5020, 5030 and 5040 can be provided on the substrate 5010 through the adhesive layer 5061 and the first and second buffer layers 5063 and 5065 interposed between them.
[0753] [0753] Each of the first to third epitaxial cells 5020, 5030 and 5040 includes semiconductor layers of type p 5025, 5035 and 5045, active layers 5023, 5033 and 5043 and semiconductor layers of type n 5021, 5031 and 5041, which are arranged sequentially.
[0754] [0754] The p-type semiconductor layer 5025, the active layer 5023 and the n-type semiconductor layer 5021 of the first epitaxial cell 5020 may include a semiconductor material that emits red light.
[0755] [0755] Examples of a semiconductor material that emits red light may include aluminum and gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), aluminum and indium and gallium phosphide (AlGaInP), gallium phosphide (GaP) or others. However, the semiconductor material that emits red light is not limited to this and several other materials can be used.
[0756] [0756] A first type 5050p contact electrode can be supplied under the type 5025 semiconductor layer of the first 5020 epitaxial cell. The first type 5050p contact electrode of the first 5020 epitaxial cell can be a single layer or a multilayer metal. For example, the first 5025p type p contact electrode can include various materials, including metals such as Al, Ti, Cr, Ni, Au, Ag, Ti, Sn, Ni, Cr, W, Cu or others or their alloys. The first contact electrode of type p 5025p can include metal with high reflectivity and, therefore, since the first contact electrode of type p 5025p is formed of metal with high reflectivity, it is possible to increase the efficiency of light emission emitted by first 5020 epitaxial cell in the upper direction.
[0757] [0757] A first n-type contact electrode 5021n can be provided in an upper portion of the n-type semiconductor layer of the first 5020 epitaxial cell. The first n-type contact electrode 5021n of the first 5020 epitaxial cell can be a single layer or a multilayer metal. For example, the first contact electrode of type n 5021n can be formed from various materials, including metals such as Al, Ti, Cr, Ni, Au, Ag, Ti, Sn, Ni, Cr, W, Cu or others or alloys thereof . However, the material of the first contact electrode of type n 5021n is not limited to those mentioned above and, consequently, other conductive materials can be used.
[0758] [0758] The second epitaxial cell 5030 includes a semiconductor layer of type n 5031, an active layer 5033 and a semiconductor layer of type p 5035, which are arranged sequentially. The semiconductor layer type 5031, the active layer 5033 and the semiconductor layer type p 5035 can include a semiconductor material that emits green light. Examples of materials for emitting green light include gallium nitride (AlGaInP) and aluminum and gallium phosphide (GaP), aluminum and indium and gallium phosphide (AlGaInP), and aluminum and gallium phosphide (AlGaP). However, the semiconductor material that emits the green light is not limited to it and several other materials can be used.
[0759] [0759] A second p 5035p contact electrode is provided under the p 5035 semiconductor layer of the second 5030 epitaxial cell. The second p 5035p contact electrode is provided between the first 5020 epitaxial cell and the second epitaxial cell 5030, or specifically, between the first buffer layer 5063 and the second epitaxial cell 5030.
[0760] [0760] Each of the second type 5035p contact electrodes can include a transparent conductive oxide (TCO). The transparent conductive oxide can include tin oxide (SnO), indium oxide (InO2), zinc oxide (ZnO), indium and tin oxide (ITO), indium and tin oxide (ITZO) or others. The transparent conductive compound can be deposited by chemical vapor deposition (CVD), physical vapor deposition (PVD), such as an evaporator, a spray or others. The second contact electrode of type p 5035p can be supplied with a thickness sufficient to serve as an attack stopper in the manufacturing process to be described below, for example, with a thickness of about 5001 angstroms at about 2 micrometers, at insofar as transparency is satisfied.
[0761] [0761] The third epitaxial cell 5040 includes a semiconductor layer of type p 5045, an active layer 5043 and a semiconductor layer of type n 5041, which are arranged sequentially. The semiconductor layer type p 5045, the active layer 5043 and the semiconductor layer type n 5041 can include a semiconductor material that emits blue light. Examples of materials that emit blue light may include gallium nitride (GaN), indium and gallium nitride (InGaN), zinc selenide (ZnSe) or others. However, the semiconductor material that emits blue light is not limited to this and several other materials can be used.
[0762] [0762] A third p 5045p contact electrode is provided under the p 5045 semiconductor layer of the third 5040 epitaxial cell. The third p 5045p contact electrode is supplied between the second 5030 epitaxial cell and the third epitaxial cell 5040, or specifically, between the second buffer layer 5065 and the third epitaxial cell 5040.
[0763] [0763] The second p 5035p contact electrode and the third p 5045p contact electrode between the p 5035 semiconductor layer of the second 5030 epitaxial cell and the p 5045 semiconductor layer of the third 5040 epitaxial cell are electrodes shared by the second epitaxial cell 5030 and the third epitaxial cell 5040.
[0764] [0764] Since the second type p contact electrode
[0765] [0765] In the exemplary example illustrated, although semiconductor layers of type 5021, 5031 and 5041 and semiconductor layers of type p 5025, 5035 and 5045 from the first to the third epitaxial cells 5020, 5030 and 5040 are shown as a single layer, these layers can be multilayered and can also include superstructure layers. In addition, active layers 5023, 5033 and 5043 of the first to third epitaxial cells 5020, 5030 and 5040 can include a single quantum well structure or a multi-quantum well structure.
[0766] [0766] In an exemplary embodiment, the second and third contact electrodes of the type p 5035p and 5045p, which are shared electrodes, substantially cover the second and third epitaxial cells 5030 and 5040. The second and third contact electrodes of the type p 5035p and 5045p can include a transparent conductive material to transmit light from the epitaxial cell below. For example, each of the second and third contact electrodes of the type p 5035p and 5045p may include a transparent conductive oxide (TCO). The transparent conductive oxide can include tin oxide (SnO), indium oxide (InO2), zinc oxide (ZnO), indium and tin oxide (ITO), indium and tin oxide (ITZO) or others. The transparent conductive compound can be deposited by chemical vapor deposition (CVD), physical vapor deposition (PVD), such as an evaporator, a spray or others. The second and third contact electrodes of the type p 5035p and 5045p can be supplied with a thickness sufficient to serve as an attack stopper in the manufacturing process to be described below, for example, with a thickness of about 5001 angstroms at about 2 micrometers to the extent that transparency is met.
[0767] [0767] In an exemplary mode, common lines can be connected to the first to third contact electrodes of the type p 5025p, 5035p and 5045p. In this case, the common line is a line to which the common voltage is applied. In addition, the light emitting signal lines can be connected to semiconductor layers of type n 5021, 5031 and 5041 of the first to third epitaxial cells 5020, 5030 and 5040, respectively. A common SC voltage is applied to the first p 5025p contact electrode, the second p 5035p contact electrode and the third p 5045p contact electrode through the common line, and the light emitting signal is applied to the layer type n semiconductor 5021 from the first epitaxial cell 5020, type n semiconductor layer 5031 from the second epitaxial cell 5030 and type n semiconductor layer 5041 from the third epitaxial cell 5040 through the light emitting signal line, thus controlling the light emission of the first to third epitaxial cells 5020, 5030 and 5040. The light emitting signal includes the first to third light emitting signals SR, SG and SB corresponding to the first to third epitaxial cells 5020, 5030 and 5040, respectively. In an exemplary embodiment, the first light emitting signal SR can be a signal corresponding to red light, the second light emitting signal SG can be a signal corresponding to green light and the third light emitting signal SB can be a signal corresponding to a blue light emission.
[0768] [0768] In the exemplary illustrated mode described above, it is described that a common voltage is applied to layers 5025, 5035 and 5045 of type p semiconductors of the first to third epitaxial cells 5020, 5030 and 5040, and the light emitting signal is applied to semiconductor layers of type n 5021, 5031 and 5041 from the first to the third epitaxial cell 5020, 5030 and 5040, but the inventive concepts are not limited to these. In another exemplary embodiment, a common voltage can be applied to layers 5021, 5031 and 5041 of type n semiconductors from the first to the third epitaxial cells 5020, 5030 and 5040, and light emitting signals can be applied to the type 5025 semiconductor layers, 5035 and 5045 from the first to the third epitaxial cells 5020, 5030 and 5040.
[0769] [0769] In this way, the first to third epitaxial cells 5020, 5030 and 5040 are activated, according to a light emitting signal applied to each of the epitaxial cells. In particular, the first epitaxial cell 5020 is activated according to a first light emitting SR signal, the second epitaxial cell 5030 is activated according to a second light emitting SG signal and the third epitaxial cell 5040 is activated according to the third SB light emitting signal. In this case, the first, second and third trigger signals SR, SG and SB are applied independently to the first to third epitaxial cells 5020, 5030 and 5040 and, as a result, each of the first to third epitaxial cells 5020, 5030 and 5040 are triggered independently. The stacked light-emitting structure can finally provide light of various colors by combining the first to third colors emitted upwards from the first to the third epitaxial cell 5020, 5030 and 5040.
[0770] [0770] The stacked light-emitting structure, according to an exemplary embodiment, can implement a color in such a way that portions of different colored lights are provided in the overlapping region, instead of implementing different colored lights in different planes, apart one on the other, providing, with advantage, compactness and integration of the light emitting element. In a conventional light-emitting element, to obtain full colors, the light-emitting elements that emit different colors, such as red, green and blue light, are generally separated from each other in a plane, which would occupy a relatively large area like each other. of the light-emitting elements is laid out in a plane. However, in the stacked light-emitting structure, according to an exemplary embodiment, it is possible to obtain a full color in a noticeably smaller area compared to the conventional light-emitting element, providing a stacked structure with the portions of the light-emitting elements that emit different colored light superimposed on a region. Consequently, it is possible to manufacture a high resolution device even in a small area.
[0771] [0771] In addition, the stacked light-emitting structure, according to an exemplary modality, significantly reduces defects that may occur during manufacture. In particular, the stacked light-emitting structure can be manufactured by stacking in the order of the first to third epitaxial cells; in this case, the second epitaxial cell is stacked in a state where the first epitaxial cell is stacked and the third epitaxial cell is stacked in a state where the first and second epitaxial cells are stacked. However, since the first to third epitaxial cells are manufactured first on a separate temporary substrate and then stacked when transferred to the substrate, defects may occur during the transfer to the substrate and removal of the temporary substrate, from the first to the third. third epitaxial cells and other components of the first to third epitaxial cells can be exposed to stress or impact. However, since the light-emitting stacked structure, according to an exemplary embodiment, includes a buffer layer, or a stress or shock absorbing layer, between adjacent epitaxial cells, defects that can occur during processing can be reduced .
[0772] [0772] In addition, the conventional light-emitting device has a complex structure and therefore requires a complicated manufacturing process, as it would require separate preparation of the respective light-emitting elements and the formation of separate contacts, such as connection by lines interconnection or other, for each of the light-emitting elements. However, according to an exemplary embodiment, the stacked light-emitting structure is formed by stacking several layers of epitaxial cells sequentially on a single 5010 substrate and forming contacts in the multilayer epitaxial cells and connecting by lines through a minimal process. Furthermore, since the individual colored light-emitting elements are manufactured and assembled separately, only a single stacked light-emitting structure is assembled, according to an exemplary embodiment, instead of a plurality of light-emitting elements. Therefore, the manufacturing method is significantly simplified.
[0773] [0773] The stacked light-emitting structure, according to an exemplary embodiment, can additionally employ several components to provide high purity and high-efficiency colored light. For example, a stacked light-emitting structure, according to an exemplary embodiment, may include a wavelength pass filter to prevent short-wavelength light from proceeding towards the epitaxial cell that emits wavelength light. relatively long.
[0774] [0774] In the following exemplary modalities, in order to avoid redundant descriptions, the differences in the exemplary modalities described above will mainly be described.
[0775] [0775] FIG. 76 is a cross-sectional view of a stacked light-emitting structure including a pass filter of predetermined wavelength according to an exemplary embodiment.
[0776] [0776] Referring to FIG. 76, a first wavelength pass filter 5071 can be provided between the first epitaxial cell 5020 and the second epitaxial cell 5030 in a stacked light-emitting structure, according to an exemplary embodiment.
[0777] [0777] The first 5071 wavelength pass filter selectively transmits a certain wavelength light and can transmit a first colored light emitted from the first 5020 epitaxial cell while blocking or reflecting light other than the first colored light. Therefore, the first colored light emitted from the first epitaxial cell 5020 can travel in the upper direction, while the second and third colored lights emitted from the second and third epitaxial cells 5030 and 5040 are prevented from traveling towards the first epitaxial cell 5020, and can be reflected or blocked by the first 5071 wavelength pass filter.
[0778] [0778] The second and third colored lights are high energy light that can have a relatively shorter wavelength than the first colored light, which can emit additional light emission in the first 5020 epitaxial cell upon entering the first 5020 epitaxial cell. In an exemplary embodiment, the second and third colored lights can be prevented from entering the first 5020 epitaxial cell by the first 5071 wavelength pass filter.
[0779] [0779] In an exemplary embodiment, a second 5073 wavelength pass filter can be provided between the second 5030 epitaxial cell and the third 5040 epitaxial cell. The second 5073 wavelength pass filter transmits the first colored light and the second colored light emitted from the first and second epitaxial cells 5020 and 5030, while blocking or reflecting light other than the first and second colored lights. Therefore, the second and second colored lights emitted by the first and second epitaxial cells 5020 and 5030 can travel in the upper direction, while the third colored light emitted by the third epitaxial cell 5040 cannot travel in one direction towards the first and second cells epitaxial 5020 and 5030, but reflected or blocked by the second 5073 wavelength pass filter.
[0780] [0780] As described above, the third colored light is a relatively high energy light, with a shorter wavelength than the first and second colored lights and, when entering the first and second epitaxial cells 5020 and 5030, the third colored light can induce additional emission in the first and second 5020 and 5030 epitaxial cells. In an exemplary embodiment, the second 5073 wavelength pass filter prevents the third light from entering the first and second 5020 and 5030 epitaxial cells.
[0781] [0781] The first and second 5071 and 5073 wavelength pass filters can be formed in various forms and can be formed by insulation films stacked alternately with different refractive indices. For example, the wavelength of the transmitted light can be determined by alternately stacking SiO2 and TiO2 and adjusting the thickness and stacking number of SiO2 and TiO2. Insulation films with different refractive indices can include SiO2, TiO2, HfO2, Nb2O5, ZrO2, Ta2O5 or others.
[0782] [0782] When the first and second 5071 and 5073 wavelength pass filters are formed by stacking inorganic insulation films with different refractive indices from one another, defects due to stress or impact during the manufacturing process, for example For example, peeling or cracking may occur. However, according to an exemplary embodiment, these defects can be significantly reduced by providing a buffer layer to alleviate the impact.
[0783] [0783] The stacked light-emitting structure, according to an exemplary embodiment, can additionally employ several components to provide uniform high-efficiency light. For example, a stacked light-emitting structure, according to an exemplary embodiment, may have several irregularities (or rough surfaces) in the light-emitting surface. For example, a stacked light-emitting structure, according to an exemplary embodiment, may have irregularities formed on the upper surface of at least one n-type semiconductor layer of the first to third epitaxial cells 5020, 5030 and 5040.
[0784] [0784] In an exemplary mode, the irregularities of each epitaxial cell can be formed selectively. For example, irregularities can be provided in the first epitaxial cell 5020, irregularities can be provided in the first and third epitaxial cells 5020 and 5040, or irregularities can be provided in the first to third epitaxial cells 5020, 5030 and 5040. The irregularities in each of the epitaxial cells can be provided in a n-type semiconductor layer corresponding to the emission surface of each of the epitaxial cells.
[0785] [0785] Irregularities are provided to increase the efficiency of light emission and can be provided in several ways, such as a polygonal pyramid, a hemisphere or planes with a roughness of the surface in a random arrangement. The irregularities can be textured through various engraving processes or using a standardized sapphire substrate.
[0786] [0786] In an exemplary embodiment, the first to third colored lights of the first to third epitaxial cells 5020, 5030 and 5040 can have different light intensities and this difference in intensity can lead to differences in visibility. The efficiency of the light emission can be improved by the selective formation of irregularities in the light output surface of the first to the third epitaxial cells 5020, 5030 and 5040, which results in the reduction of the differences in visibility between the first and the third colored lights . The colored light corresponding to the red and / or blue color may have less visibility than the green color; in this case, the first epitaxial cell 5020 and / or the third epitaxial cell 5040 can be textured to reduce the difference in visibility. In particular, when the lower part of the light-emitting batteries emits red light, the light intensity may be small. As such, the luminous efficiency can be increased by the formation of irregularities on its upper surface.
[0787] [0787] The stacked light-emitting structure with the structure described above is a light-emitting element capable of expressing various colors and therefore can be used as a pixel in a display device. In the exemplary embodiment below, a display device will be described as including the stacked light-emitting structure according to exemplary embodiments.
[0788] [0788] FIG. 77 is a plan view of a display apparatus according to an exemplary embodiment, and FIG. 78 is an enlarged plan view showing a portion P1 of FIG.
[0789] [0789] Referring to FIGS. 77 and 78, a display device 5110 according to an exemplary embodiment can display any visual information, text, video, photographs, two-dimensional or three-dimensional image, or others.
[0790] [0790] The 5110 display device can be supplied in several forms, including a closed polygon that includes a straight side, such as a rectangle or circle, an ellipse or the like, which includes a curved side, a semicircle or semi-ellipse that includes a combination of straight and curved sides. In an exemplary embodiment, the display device will be described as having substantially a rectangular shape.
[0791] [0791] The 5110 display device has a plurality of 5110 pixels for displaying images. Each of the 5110 pixels can be a minimum unit to display the image. Each 5110 pixel includes the stacked light-emitting structure with the structure described above and can emit white light and / or colored light.
[0792] [0792] In an exemplary embodiment, each pixel includes a first 5110R pixel that emits red light, a second 5110G pixel that emits green light, and a third 5110B pixel that emits blue light. The first to third pixels 5110R, 5110G and 5110B can correspond to the first to third epitaxial cells 5020, 5030 and 5040 of the stacked light-emitting structure described above, respectively.
[0793] [0793] The 5110 pixels are arranged in a matrix. As used here, pixels arranged in "a matrix" may not only refer to when 5110 pixels are arranged in a row along the line or column, but also when 5110 pixels are arranged in any repetitive pattern, as generally along the rows and columns, with certain modifications in the details, such as the 5110 pixels, being arranged in a zigzag shape, for example.
[0794] [0794] FIG. 79 is a structural diagram of a display device, according to an exemplary embodiment.
[0795] [0795] Referring to FIG. 79, the display device 5110 according to an exemplary embodiment includes a 5350 timing controller, a 5310 scanning driver, a 5330 data driver, a spinning unit and pixels. When the pixels include a plurality of pixels, each of the pixels is individually connected to the 5310 scan driver, the 5330 data driver or the like via a portion of the wiring.
[0796] [0796] The 5350 timing controller receives various control signals and image data necessary to drive the display device from the outside (for example, a system for transmitting image data). The 5350 timing controller reorganizes the received image data and transmits the image data to the 5330 data driver. In addition, the 5350 timing controller generates scan control signals and data control signals necessary to drive the image driver. scan 5310 and 5330 data driver and transmit the scan control signals and data control signals that are generated to the 5310 scan driver and 5330 data driver.
[0797] [0797] The scan driver 5310 receives scan control signal from the 5350 timing controller and generates a corresponding scan signal. The 5330 data driver receives data control signal and image data from the 5350 timing controller, and generates corresponding data signals.
[0798] [0798] The wiring unit includes a plurality of signal lines. The wiring portion includes the 5130 scan lines connecting the 5310 scan driver and the pixels and the 5120 data lines connecting the 5330 data driver and the pixels. The scan lines 5130 can be connected to the respective pixels and, consequently, the scan lines
[0799] [0799] In addition, the wiring unit includes lines connecting between the 5350 timing controller to the 5310 scanning driver, the 5350 timing controller and the 5330 data driver or other components and transmitting the signals.
[0800] [0800] The 5130 scan lines provide the scan signals generated from the 5310 scan driver to the pixels. The data signals generated from the 5330 data driver are sent to the 5120 data lines.
[0801] [0801] The pixels are connected to the 5130 scan lines and the 5120 data lines. The pixels selectively emit light in response to the data signals emitted from the 5120 data lines when the scan signals are provided from the data lines. scan 5130. For example, during each frame period, each of the pixels emits light with the corresponding luminance for the input data signals. The pixels provided with the data signals corresponding to the black luminance display black, emitting no light during the corresponding frame period.
[0802] [0802] In an exemplary mode, pixels can be activated as either passive or active. When the display device is activated in an active manner, the display device can be supplied with the first and second pixel power in addition to the scan signals and the data signals.
[0803] [0803] FIG. 80 is a one-pixel circuit diagram of a passive display device. The pixel can be one of the R, G, B pixels and the first 5110R pixel is illustrated as an example. Since the second and third pixels can be triggered in substantially the same way as the first pixel, circuit diagrams for the second and third pixels will be omitted.
[0804] [0804] Referring to FIG. 80, the first pixel 5110R includes an emitting element 150 connected between the scan line 5130 and the data line 5120. The light emitting element 150 can correspond to the first epitaxial cell 5020. The epitaxial cell 5020 emits light with a luminance corresponding to a magnitude of the applied voltage when a voltage equal to or greater than a threshold voltage is applied between the p-type semiconductor layer and the n-type semiconductor layer. In particular, the emission of the first 5110R pixel can be controlled by controlling the voltages of the scan signal applied to the first scan line 5130R and / or the data signal applied to the data line
[0805] [0805] FIG. 81 is a circuit diagram of a first pixel of an active type display device.
[0806] [0806] When the display device is of the active type, the first 5110R pixel can be supplied with the first and second pixel power (ELVDD and ELVSS) in addition to the scan signal and the data signal.
[0807] [0807] Referring to FIG. 81, the first pixel 5110R includes a light-emitting element 150 and a piece of the transistor connected thereto. The light-emitting element 150 can correspond to the first epitaxial cell 5020, and the p-type semiconductor layer of the light-emitting element 150 can be connected to the first pixel energy source ELVDD through the transistor part and the n-type semiconductor layer. can be connected to a second pixel ELVSS power supply. The first source of pixel energy ELVDD and the second source of pixel energy
[0808] [0808] According to an exemplary embodiment, the transistor part includes the first and second transistors M1 and M2 and a Cst storage capacitor. However, the inventive concepts are not limited to these and the structure of the transistor part can be varied.
[0809] [0809] The source electrode of the first M1 transistor (for example, a switching transistor) is connected to the 5120 data line, and a drain electrode is connected to a first N1 node. In addition, a gate electrode from the first transistor is connected to the first scan line 5130R. The first transistor is activated when a scan signal of a voltage capable of connecting the first transistor M1 is provided from the first scan line 5130R to the data line 5120, to electrically connect the first node N1. The data signal of the corresponding frame is supplied to data line 5120 and, therefore, the data signal is transmitted to the first node N1. The data signal transmitted to the first node N1 is loaded into the storage capacitor Cst.
[0810] [0810] The source electrode of the second transistor M2 is connected to the first pixel energy source ELVDD, and a drain electrode is connected to the first type n semiconductor layer of the light emitting element. The gate electrode of the second transistor M2 is connected to the first node N1. The second transistor M2 controls an amount of drive current supplied to the light-emitting cell in response to the voltage of the first node N1.
[0811] [0811] One electrode of the Cst storage capacitor is connected to the first ELVDD subpixel power source, and the other electrode is connected to the first N1 node. The storage capacitor Cst carries a voltage corresponding to the data signal supplied to the first node N1 and keeps the voltage charged until the data signal of the next frame is supplied.
[0812] [0812] FIG. 81 shows a transistor part including two transistors. However, the inventive concepts are not limited to these, and several modifications are applicable to the structure of the transistor part. For example, the transistor part may include more transistors, capacitors or the like. In addition, although the specific structures of the first and second transistors, storage capacitors and lines are not shown, the first and second transistors, storage capacitors and lines are not particularly limited and can be provided in a variety of ways.
[0813] [0813] Pixels can be implemented in various structures within the scope of inventive concepts. In the following, a pixel, according to an exemplary embodiment, will be described with reference to a pixel of the passive matrix type.
[0814] [0814] FIG. 82 is a plan view of a pixel according to an exemplary embodiment, and FIGS. 83A and 83B are cross-sectional views taken along lines I-I 'and II-II' of FIG. 82, respectively.
[0815] [0815] Referring to FIGS. 82, 83A and 83B, viewing from a flat view, one pixel, according to an exemplary modality,
[0816] [0816] When viewed from a flat view, the pixel, according to an exemplary mode, has a light-emitting region in which a plurality of epitaxial cells are stacked. At least one side of the light-emitting region is provided with a contact to connect the wiring piece to the first and third 5020, 5030 and 5040 epitaxial cells. The contact includes the first and second 5050GC and 5050BC common contacts for applying a voltage common to the first and third 5020, 5030 and 5040 epitaxial cells, a first 5020C contact to provide a light emitting signal for the first 5020 epitaxial cell, a second 5030C contact to provide a light emitting signal to the second 5030 epitaxial cell and a third 5040C contact to provide a light emitting signal for the third epitaxial cell
[0817] [0817] In an exemplary embodiment, the stacked structure can vary depending on the polarity of the semiconductor layers from the first to the third 5020, 5030 and 5040 epitaxial cells to which the common voltage is applied. That is, with respect to the first and second common contacts 5050GC and 5050BC, when contact electrodes are provided to apply a common voltage to each of the first to third epitaxial cells 5020, 5030 and 5040, these contact electrodes can be referred to as "first to third common contact electrodes" and first to third contact electrodes can be "first to third p type contact electrodes",
[0818] [0818] In an exemplary embodiment, when viewed from a plan view, the first and second common contacts 5050GC and 5050BC and the first to third contacts 5020C, 5030C and 5040C can be supplied in various positions. For example, when the light-emitting stacked structure is substantially square in shape, the first and second common contacts 5050GC and 5050BC and the first to third contacts 5020C, 5030C and 5040C can be arranged in regions corresponding to the respective corners of the square. However, the positions of the first and second common contacts 550GC and 550BC and from the first to the third contacts 5020C, 5030C and 5040C are not limited to these, and several modifications are applicable, according to the shape of the stacked light-emitting structure.
[0819] [0819] The plurality of epitaxial cells includes the first to third epitaxial cells 5020, 5030 and 5040. The first to third epitaxial cells 5020, 5030 and 5040 are connected with the first to third light-emitting signal lines to provide light emitting signals. light to each of the first to third epitaxial cells 5020, 5030 and 5040 and a common line to provide a voltage common to each of the first to third epitaxial cells 5020, 5030 and 5040. In an exemplary embodiment, the first to third lines of light-emitting signals can correspond to the first to the third scan lines 5130R, 5130G and 5130B, and the common line can correspond to the data line 5120. Therefore, the first to the third scan lines 5130R, 5130G and 5130B and the 5120 data is connected to the first to third epitaxial cells 5020, 5030 and 5040, respectively.
[0820] [0820] In an exemplary embodiment, the first to third scan lines 5130R, 5130G and 5130B can extend substantially in a first direction (for example, in a transverse direction, as shown in the figure). The 5120 data line can extend substantially in a second direction, crossing the first to third scan lines 5130R, 5130G and 5130B (for example, in a longitudinal direction, as shown in the figure). However, the extension directions of the first to third scan lines 5130R, 5130G and 5130B and the data line 5120 are not limited to these, and several modifications are applicable, depending on the arrangement of the pixels.
[0821] [0821] Data line 5120 and the first 5025p type p contact electrode extend substantially in a second direction that crosses the first direction, while providing a voltage common to the type p semiconductor layer of the first epitaxial cell 5020. Therefore, the 5120 data line and the first 5025p type p contact electrode can be substantially the same component. From now on, the first contact electrode of type p 5025p can be referred to as data line 5120 or vice versa.
[0822] [0822] An ohmic electrode 5025p 'for ohmic contact between the first contact electrode of type p 5025p and the first epitaxial cell 5020 are provided in the light emitting region provided with the first contact electrode of type p 5025p.
[0823] [0823] The first scan line 5130R is connected to the first 5020 epitaxial cell through the first contact hole CH1, and the data line 5120 is connected via the ohmic electrode 5025p '. The second scan line 5130G is connected to the second epitaxial cell 5030 through the second contact hole CH2 and the data line 5120 is connected through the contact holes 4ath and 4bth CH4a and CH4b. The third scan line 5130B is connected to the third epitaxial cell 5040 through the third contact hole CH3 and the data line 5120 is connected through the contact holes 5ath and 5bth CH5a and CH5b.
[0824] [0824] A buffer layer, a contact electrode, a wavelength pass filter or the like are provided between substrate 5010 and the first to third epitaxial cells 5020, 5030 and 5040, respectively. Next, the pixel, according to an exemplary mode, will be described in the stacking order.
[0825] [0825] According to an exemplary embodiment, a first epitaxial cell 5020 is provided on the substrate 5010 through an adhesive layer 5061 interposed between them. In the first 5020 epitaxial cell, a p-type semiconductor layer, an active layer and an n-type semiconductor layer are arranged sequentially from the bottom to the top.
[0826] [0826] A first 5081 insulation film is stacked on a bottom surface of the first 5020 epitaxial pile, that is, on the surface facing the 5010 substrate. A plurality of contact holes are formed in the first 5081 insulation film. contact are provided with a 5025p ohmic electrode in contact with the p-type semiconductor layer of the first 5020 epitaxial cell. The 5025p ohmic electrode can include a variety of materials. In an exemplary embodiment, the ohmic electrode 5025p 'corresponding to the ohmic electrode 5025p' type p may include an Au / Zn alloy or an Au / Be alloy. In this case, since the material of the ohmic electrode 5025p 'is lower in reflectivity than Ag, Al, Au or the like, additional reflective electrodes can be further arranged. As an additional reflective electrode, Ag, Au or the like can be used, and Ti, Ni, Cr, Ta or the like can be arranged as an adhesive layer for adhesion to adjacent components. In that case, the adhesive layer can be deposited finely on the upper and lower surfaces of the reflector electrode, including Ag, Au or the like.
[0827] [0827] The first contact electrode of type p 5025p and data line 5120 are in contact with the ohmic electrode 5025p ’. The first contact type electrode p 5025p (also serving as data line 5120) is provided between the first insulating film 5081 and the adhesive layer 5061.
[0828] [0828] When viewed from a flat view, the first p 5025p contact electrode can be provided in such a way that the first p 5025p contact electrode overlaps the first 5020 epitaxial cell, or more particularly, overlaps the light-emitting region of the first 5020 epitaxial cell, while covering most or all of the light-emitting region. The first p 5025p contact electrode may include a reflective material, so that the first p 5025p contact electrode can reflect the light from the first epitaxial cell
[0829] [0829] In addition, the material of the first 5025p type p contact electrode layer is selected from metals with high reflectivity to the light emitted from the first 5020 epitaxial cell, to maximize the reflectivity of the light emitted from the first epitaxial cell 5020. For example, when the first 5020 epitaxial cell emits red light, the metal with a high reflectivity to red light, for example Au, Al, Ag or the like can be used as material for the first contact electrode layer of the type p 5025p. Au does not have a high reflectivity to the light emitted by the second and third epitaxial cells 5030 and 5040 (for example, green light and blue light) and therefore can reduce a mixture of colors by the light emitted from the second and third epitaxial cells 5030 and 5040
[0830] [0830] The first 5071 wavelength pass filter and the first n 5021n contact electrode are provided on an upper surface of the first 5020 epitaxial cell. In an exemplary embodiment, the first n 5021n contact electrode can include various metals and metal alloys, including Au / Te alloy or Au / Ge alloy, for example.
[0831] [0831] The first 5071 wavelength pass filter is provided on the top surface of the first 5020 epitaxial cell to cover substantially the entire light-emitting region of the first 5020 epitaxial cell.
[0832] [0832] The first contact electrode of type n 5021n is supplied in a region corresponding to the first contact 5020C and may include a conductive material. The first 5071 wavelength pass filter is provided with a contact orifice through which the first type n contact electrode 5021n is placed in contact with the type n semiconductor layer on the top surface of the first 5020 epitaxial cell.
[0833] [0833] The first buffer layer 5063 is supplied in the first epitaxial cell 5020, and the second contact electrode of type p 5035p and the second epitaxial cell 5030 are supplied sequentially in the first buffer layer 5063. In the second epitaxial cell 5030, a semiconductor layer p-type, an active layer and a n-type semiconductor layer are arranged sequentially from the bottom to the top.
[0834] [0834] In an exemplary embodiment, the region corresponding to the first contact 5020C of the second epitaxial cell 5030 is removed, thus exposing a portion of the upper surface of the first contact electrode of type n 5021n. In addition, the second 5030 epitaxial cell may have a smaller area than the second type 5035p contact electrode. The region corresponding to the first common 550GC contact is removed from the second 5030 epitaxial cell, thus exposing a portion of the upper surface of the second type 5035p contact electrode.
[0835] [0835] The second 5073 wavelength pass filter, the second layer of buffer 5065 and the third p type contact electrode 5045p are supplied sequentially in the second epitaxial cell 5030. The third epitaxial cell 5040 is provided in the third electrode contact type p 5045p. In the third epitaxial cell 5040, a n-type semiconductor layer, an active layer and a p-type semiconductor layer are arranged sequentially from the bottom to the top.
[0836] [0836] The third epitaxial cell 5040 may have a smaller area than the second epitaxial cell 5030. The third epitaxial cell 5040 may have an area smaller than the third contact electrode of type p 5045p. The region corresponding to the second common contact 5050BC is removed from the third epitaxial cell 5040, thus exposing a portion of the upper surface of the third contact electrode of type p 5045p.
[0837] [0837] The second 5083 insulation film covering the stacked structure of the first to third 5020, 5030 and 5040 epitaxial cells is provided in the third 5040 epitaxial cell. The second 5083 insulation film may include various organic / inorganic insulating materials, but is not limited to them. For example, the second 5083 insulation film may include inorganic insulation material, including silicon nitride and silicon oxide, or organic insulation material, including polyimide.
[0838] [0838] The first contact hole CH1 is formed in the second insulation film 5083 to expose an upper surface of the first contact electrode of type n 5021n provided in the first contact 5020C. The first scan line is connected to the first 5021n n type contact electrode through the first CH1 contact orifice.
[0839] [0839] A third insulation film 5085 is provided on the second insulation film 5083. The third insulation film 5085 may include a material substantially the same or different from the second insulation film 5083. The third insulation film 5085 may include various insulating materials organic / inorganic, but is not limited to them.
[0840] [0840] The second and third scan lines 5130G and 5130B and the first and second bridge electrodes BRG and BRB are provided in the third insulation film 5085.
[0841] [0841] The third insulation film 5085 is provided with a second contact hole CH2 to expose an upper surface of the second epitaxial cell 5030 in the second contact 5030C, that is, to expose the n-type semiconductor layer of the second epitaxial cell 5030, a third contact hole CH3 to expose an upper surface of the third epitaxial cell 5040 in the third contact 5040C, that is, to expose a semiconductor type n layer of the third epitaxial cell 5040, 4ath and 4bth contact holes CH4a and CH4b to expose an upper surface of the first contact electrode of type p 5025p and an upper surface of the second contact electrode of type p 5035p, in the first common contact 5050GC and contact holes 5ath and 5bth CH5a and CH5b to expose an upper surface of the first contact of type p electrode 5025p and an upper surface of the third contact electrode of type p 5045p, in the second common contact 5050BC.
[0842] [0842] The second scan line 5130G is connected to the n-type semiconductor layer of the second 5030 epitaxial cell through the second contact hole CH2. The third scan line 5130B is connected to the n-type semiconductor layer of the third epitaxial cell 5040 through the third contact hole CH3.
[0843] [0843] The 5120 data line is connected to the second type 5035p contact electrode through the 4ath and 4bth contact holes CH4a and CH4b and the first BRG bridge electrode. The 5120 data line is also connected to the third type 5050p contact electrode through the 5ath and 5bth contact holes CH5a and CH5b and the second BRB bridge electrode.
[0844] [0844] It is illustrated in this document that the second and third scan lines 5130G and 5130B in an exemplary mode are electrically connected to the type n semiconductor layer of the second and third epitaxial cells 5030 and 5040 in direct contact with each other. However, in another exemplary embodiment, the second and third type n contact electrodes can still be provided between the second and third scan lines 5130G and 5130B and the type n semiconductor layers of the second and third epitaxial cells 5030 and 5040.
[0845] [0845] According to an exemplary embodiment, irregularities can be selectively provided on the upper surfaces of the first to third epitaxial cells 5020, 5030 and 5040, that is, on the upper surface of the type n semiconductor from the first to the third epitaxial cells. Each of the irregularities can be supplied only in a portion corresponding to the light-emitting region or can be supplied over the entire upper surface of the respective semiconductor layers.
[0846] [0846] In addition, in an exemplary embodiment, a substantially non-transmissive film can still be provided on the sides of the second and / or third insulation films 5083 and 5085 that correspond to the sides of the pixel. Non-transmissive film is a light blocking film that includes an absorbent or light reflecting material, which is provided to prevent light from the first to third 5020, 5030 and 5040 epitaxial cells from appearing on the sides of the pixel.
[0847] [0847] In an exemplary embodiment, the optically non-transmissive film can be formed as a single or multilayer metal. For example, optically non-transmissive film can be formed from a variety of materials,
[0848] [0848] The optically non-transmissive film can be supplied on the side of the second insulating film 5083 as a separate layer formed of a material such as metal or alloy thereof.
[0849] [0849] The optically non-transmissive film can be provided in a way that extends laterally from at least one of the first to the third scan lines 5130R, 5130G and 5130B and the first and second bridge electrodes BRG and BRB. In this case, the optically non-transmissive film extending from one of the first to the third scan lines 5130R, 5130G and 5130B and the first and second bridge electrodes BRG and BRB are provided within a limit that is not electrically connected to others conductive components.
[0850] [0850] In addition, a substantially non-transmissive film can be provided, formed separately from the first to third scan lines 5130R, 5130G and 5130B and the first and second bridge electrodes BRG and BRB, on the same layer and using substantially the same material during the same formation process of at least one of the first to third scan lines 5130R, 5130G and 5130B and the first and second bridge electrodes BRG and BRB. In this case, the non-transmissive film can be electrically isolated from the first to the third scan lines 5130R, 5130G and 5130B and the first and second bridge electrodes BRG and BRB.
[0851] [0851] Alternatively, when no optically non-transmissive film is supplied separately, the second and third insulation films 5083 and 5085 can serve as optically non-transmissive films. When the second and third insulation films 5083 and 5085 are used as an optically non-transmissive film, the second and third insulation films 5083 and 5085 may not be provided in a region corresponding to an upper portion (front direction) of the first to the third epitaxial cells 5020, 5030 and 5040 to allow the light emitted from the first to the third epitaxial cells 5020, 5030 and 5040 to travel in the frontal direction.
[0852] [0852] The substantially non-transmissive film is not particularly limited as long as it blocks the transmission of light by absorbing or reflecting light. In an exemplary embodiment, the non-transmissive film may be a distributed Bragg reflector (DBR) dielectric mirror, a metal reflective film formed in an insulation film, or a black organic polymer film. When a metal reflective film is used as a non-transmissive film, the metal reflective film may be in a floating state that is electrically isolated from components within other pixels.
[0853] [0853] By providing the non-transmissive film on the sides of the pixels, it is possible to avoid the phenomenon in which the light emitted by a given pixel affects the adjacent pixels or in which the color is mixed with the light emitted by the adjacent pixels.
[0854] [0854] The pixel that has the structure described above can be manufactured by sequentially stacking the first to third epitaxial cells 5020, 5030 and 5040 on the substrate 5010 sequentially and standardizing it, which will be described in detail below.
[0855] [0855] FIGS. 84A to 84C are seen in cross section of line I-I 'in FIG. 82, illustrating a process of stacking first to third epitaxial cells on a substrate.
[0856] [0856] Referring to FIG. 84A, the first epitaxial cell 5020 is formed on the substrate 5010.
[0857] [0857] The first epitaxial cell 5020 and the ohmic electrode 5025p 'are formed on a first temporary substrate 5010p. In an exemplary embodiment, the first temporary substrate 5010p can be a semiconductor substrate, such as a GaAs substrate, to form the first 5020 epitaxial cell. The first 5020 epitaxial cell is manufactured in a way to stack the n-type semiconductor layer, the active layer and the p-type semiconductor layer on the first temporary substrate 5010p. The first insulation film 5081 having a contact orifice formed on it is formed on the first temporary substrate 5010p, and the ohmic electrode 5025p 'is formed within the contact orifice of the first insulation film 5081.
[0858] [0858] The ohmic electrode 5025p 'is formed by forming the first insulating film 81 on the first temporary substrate 5010p, applying photoresist, standardizing the photoresistor, depositing an ohmic electrode material 5025p' on the standardized photoresistor and then removing the pattern photoresistor. However, the method of forming the 5025p ohmic electrode is not limited to this. For example, the first insulation film 81 can be formed by forming the first insulation film 81, standardizing the first insulation film 81 by photolithography, forming the ohmic electrode film 5025p 'with the material of the ohmic electrode film 5025p' and standardizing the ohmic electrode film 5025p 'by photolithography.
[0859] [0859] The first 5025p type p contact electrode layer (also serving as data line 5120) is formed on the first temporary substrate 5010p on which the ohmic electrode 5025p 'is formed. The first 5025p type p contact electrode layer may include a reflective material. The first layer of contact electrode type p 5025p can be formed by, for example, depositing a metal material and then standardizing it using photolithography.
[0860] [0860] The first epitaxial cell 5020 formed on the first temporary substrate 5010p is inverted and fixed to the substrate 5010 through the adhesive layer 5061 interposed between them.
[0861] [0861] After the first 5020 epitaxial cell is attached to substrate 5010, the first temporary substrate 5010p is removed. The first temporary 5010p substrate can be removed by various methods, such as wet etching, dry etching, physical removal, laser removal or the like.
[0862] [0862] Referring to FIG. 84B, after removing the first temporary substrate 5010p, the first type n contact electrode 5021n, the first wavelength pass filter 5071 and the first adhesion enhancement layer 5063a are formed in the first epitaxial cell 5020. The first contact electrode type n 5021n can be formed by depositing a conductive material and then standardizing by the photolithography process. The first 5071 wavelength pass filter can be formed by alternately stacking insulation films with different refractive indices from one another.
[0863] [0863] After lifting the first temporary substrate 5010p, irregularities can be formed on an upper surface (type n semiconductor layer) of the first 5020 epitaxial pile. Irregularities can be formed by textures with various engraving processes. For example, irregularities can be formed by various methods, such as dry engraving using a microphotography process, wet engraving using a crystal feature, texturing using a physical method such as sandblasting, ion beam engraving, texturization based the difference in the recording rates of block copolymers or the like.
[0864] [0864] The second epitaxial cell 5030, the second p type contact electrode layer 5035p and the first shock absorption layer 5063b are formed on a separate second temporary substrate 5010q.
[0865] [0865] The second temporary substrate 5010q can be a sapphire substrate. The second epitaxial cell 5030 can be manufactured by forming the n-type semiconductor layer, the active layer and the p-type semiconductor layer on the second temporary substrate 5010q.
[0866] [0866] The second epitaxial cell 5030 formed on the second temporary substrate 5010q is inverted and attached to the first epitaxial cell 5020. In this case, the first layer 5063a for improving adhesion and the second layer 5063b for shock absorption can be arranged one in front to the other and then joined. In an exemplary embodiment, the first adhesion enhancing layer 5063a and the first shock absorbing layer 5063b can include various materials, such as SOG and silicon oxide, respectively.
[0867] [0867] After connection, the second temporary substrate 5010q is removed. The second temporary 5010q substrate can be removed by various methods, such as wet etching, dry etching, physical removal, laser removal or the like.
[0868] [0868] According to an exemplary embodiment, in the process of attaching the second epitaxial cell 5030 formed on the second temporary substrate 5010q to the substrate 5010, and in the process of removing the second temporary substrate 5010q from the second epitaxial cell 5030, the impact applied to the first epitaxial cell 5020, the second epitaxial cell 5030, the first wavelength pass filter 5071 and the second contact electrode of type p 5035p, are absorbed and / or relieved by the first buffer layer 5063, more particularly, by the first layer of shock absorption 5063b within the first layer 5063. This minimizes the cracking and peeling that can occur in the first epitaxial cell 5020, the second epitaxial cell 5030, the first 5071 wavelength pass filter and the second type contact electrode p 5035p. More particularly, when the first 5071 wavelength pass filter is formed on the top surface of the first 5020 epitaxial cell, the possibility of peeling is noticeably reduced compared to when the first 5071 wavelength pass filter is formed on the side of the second epitaxial cell 5030. When the first 5071 wavelength pass filter is formed on the upper surface of the second epitaxial cell 5030 and then attached to the first side of the epitaxial cell 5020, due to the impact generated in the process of lifting the second temporary substrate 5010q, there may be a peeling defect of the first 5071 wavelength pass filter. However, according to an exemplary embodiment, in addition to the first 5071 wavelength pass filter being formed on the first side of the 5020 epitaxial cell, the shock-absorbing effect by the first 5063b shock-absorbing layer can prevent the occurrence defects, such as peeling.
[0869] [0869] Referring to FIG. 84C, the second wavelength pass filter 5073 and the second adhesion enhancement layer 5065a are formed in the second epitaxial stack 5030 from which the second temporary substrate 5010q has been removed.
[0870] [0870] The second 5073 wavelength pass filter can be formed by alternately stacking insulation films with different refractive indices from one another.
[0871] [0871] Irregularities can be formed on an upper surface (type n semiconductor layer) of the second 5030 epitaxial cell after removal of the second temporary substrate. Irregularities can be textured through various engraving processes, or they can be formed using a standard sapphire substrate for the second temporary substrate.
[0872] [0872] The third epitaxial cell 5040, the third layer of contact type electrode p 5045p and the second layer of shock absorption 5065b are formed on a separate third temporary substrate 5010r.
[0873] [0873] The third temporary substrate 5010r may be a sapphire substrate. The third epitaxial cell 5040 can be manufactured by forming the n-type semiconductor layer, the active layer and the p-type semiconductor layer on the third temporary substrate 5010r.
[0874] [0874] The third epitaxial cell 5040 formed on the third temporary substrate 5010r is inverted and attached to the second epitaxial cell 5030. In this case, the second layer 5065a of adhesion improvement and the second layer 5065b of shock absorption can be arranged one in front to the other and then joined. In an exemplary embodiment, the second adhesion enhancing layer 5065a and the second shock absorbing layer 5065b can include various materials, such as SOG and silicon oxide, respectively.
[0875] [0875] After fixing, the third temporary substrate 5010r is removed. The third temporary substrate 5010r can be removed by various methods, such as wet etching,
[0876] [0876] According to an exemplary embodiment, in the process of attaching the third epitaxial cell 5040 formed on the third temporary substrate 5010r to the substrate 5010, and in the process of removing the third temporary substrate 5010r from the third epitaxial cell 5040, the impact applied to the second and third epitaxial cells 5030 and 5040, the second wavelength pass filter 5073 and the third p type contact electrode 5045p are absorbed and / or relieved by the second layer of buffer 5065, in particular, by the second layer of absorption of shock 5065b within the second layer of buffer 5065.
[0877] [0877] Therefore, all the first to third epitaxial cells 5020, 5030 and 5040 are stacked on the substrate 5010.
[0878] [0878] Irregularities can be formed on an upper surface (type n semiconductor layer) of the third epitaxial cell 5040 after the elevation of the second temporary substrate. The irregularities can be textured through various engraving processes or can be formed using a sapphire substrate standardized for the second temporary substrate 5010q.
[0879] [0879] Next, a method of manufacturing a pixel will be described, standardizing epitaxial cells stacked according to an exemplary modality.
[0880] [0880] FIGS. 85, 87, 89, 91, 93, 95 and 97 are plan views showing sequentially a method of manufacturing a pixel on a substrate, according to an exemplary modality.
[0881] [0881] FIGS. 86A, 86B, 88A, 88B, 90A, 90B, 92A, 92B, 94A, 94B, 96A, 96B, 98A and 98B are views taken along line I-I 'and line II-II' of the corresponding figures, respectively.
[0882] [0882] Referring to FIGS. 85, 86A and 86B, first, the third 5040 epitaxial cell is standardized. Most of the third 5040 epitaxial cell, except for the light emitting region, is removed and, in particular, the portions corresponding to the first and second contacts 5030C and the first and second common contacts 5050GC and 5050BC are removed. The third 5040 epitaxial cell can be removed by various methods, such as wet etching or dry etching using photolithography, and the third p 5045p type contact electrode can function as a recording stopper.
[0883] [0883] Referring to FIGS. 87, 88A and 88B, the third p-type contact electrode 5045p, the second layer of buffer 5065 and the second wavelength filter 5073 are removed from the region, excluding the light-emitting region. As such, a portion of the upper surface of the second epitaxial cell 5030 is exposed at the second contact 5030C.
[0884] [0884] The third p 5045p type contact electrode, the second 5065 buffer layer and the second 5073 wavelength pass filter can be removed by various methods, such as wet recording or dry recording using photolithography.
[0885] [0885] Referring to FIGS. 89, 90A to 90, a portion of the second 5030 epitaxial cell is removed, exposing a portion of the upper surface of the second type 5035p contact electrode to the second common contact 5050GC to the outside. The third contact electrode of type p 5045p serves as an engraving stopper during engraving.
[0886] [0886] Then, parts of the second p type contact electrode 5035p, the first layer of buffer 5063 and the first pass filter of wavelength 5071 are recorded. Accordingly, the upper surface of the first n-type contact electrode 5021n is exposed in the first contact 5020C, and the upper surface of the first epitaxial cell 5020 is exposed in portions other than the light-emitting region.
[0887] [0887] The second epitaxial cell 5030, the second p type contact electrode 5035p, the first buffer layer 5063 and the first 5071 wavelength pass filter can be removed by various methods, such as wet recording or dry recording using photolithography.
[0888] [0888] Referring to FIGS. 91, 92A and 92B, the first 5020 epitaxial cell and the first 5081 insulation film are recorded in the region excluding the light-emitting region. The upper surface of the first 5025p type p contact electrode is exposed on the first and second common contacts 5050GC and 5050BC.
[0889] [0889] Referring to FIGS. 93, 94A and 94B, the second insulation film 5083 is formed in front of the substrate 5010 and first to the third contact holes CH1, CH2, CH3, contact holes 4ath and 4bth CH4a and CH4b and 5ath and 5bth the contact holes CH5a and CH5b are formed.
[0890] [0890] After deposition, the second 5083 insulation film can be standardized by various methods, such as wet recording or dry recording using photolithography.
[0891] [0891] Referring to FIGS. 95, 96A and 96B, the first scan line 5130R is formed on the second standardized insulation film 5083. The first scan line 5130R is connected to the first contact electrode of type n 5021n through the first contact hole CH1 on the first contact 5020C .
[0892] [0892] The first scan line 5130R can be formed in several ways. For example, the first scan line 5130R can be formed by photolithography using a plurality of mask sheets.
[0893] [0893] Next, the third insulation film 5085 is formed on the front of the substrate 5010, and the second and third contact holes CH2 and CH3, the contact holes 4ath and 4bth CH4a and CH4b and the contact holes 5ath and 5bth CH5a and CH5b are formed.
[0894] [0894] After deposition, the third 5085 insulation film can be standardized by several methods, such as wet recording or dry recording using photolithography.
[0895] [0895] Referring to FIGS. 97, 98A and 98B, the second scan line 5130G, the third scan line 5130B, the first BRG bridge electrode and the second BRB bridge electrode are formed from a third standardized 5085 insulation film.
[0896] [0896] The second scan line 5130G is connected to the type n semiconductor layer of the second 5030 epitaxial cell through the second contact hole CH2 on the second contact 5030C. The third scan line 5130B is connected to the n-type semiconductor layer of the fourth epitaxial cell 5040 through a third contact hole CH3 in the third contact 5040C. The first BRG bridge electrode is connected to the first 5025p type p contact electrode through the 4ath and 4bth CH4a and CH4b contact holes in the first 5050GC common contact. The second BRB bridge electrode is connected to the first type 5025p contact electrode through the 5ath and 5bth contact holes CH5a and CH5b on the second common contact 5050BC.
[0897] [0897] The second scan line 5130G, the third scan line 5130B and the bridge electrode 5120b can be formed on the third insulation film 5085 in several ways, for example, by photolithography using a plurality of mask sheets.
[0898] [0898] The second scan line 5130G, the third scan line 5130B and the first and second bridge electrodes BRG and BRB can be formed by applying photoresist to substrate 5010 on which the third insulation film 5085 is formed and standardizing the photoresistor and depositing materials from the second scan line, the third scan line and the bridge electrode onto the standard photoresistor and then removing the photoresistor pattern.
[0899] [0899] According to an exemplary embodiment, the order to form the first to third scan lines 5130R, 5130G and 5130B and the first and second bridge electrodes BRG and BRB of the wiring piece is not particularly limited and can be formed in multiple strings. For example, it is illustrated that the second scan line 5130G, the third scan line 5130B and the first and second bridge electrodes BRG and BRB are formed in the third insulation film 5085 at the same stage, but can be formed in a different order. For example, the first scan line 5130R and the second scan line 5130G can be formed first in the same step, followed by the formation of the additional insulation film and then by the third scan line 5130B. Alternatively, the first scan line 5130R and the third scan line 5130B can be formed first in the same step, followed by the formation of the additional insulation film and then the formation of the second scan line 5130G. In addition, the first and second BRG and BRB bridge electrodes can be formed together at any of the forming stages from the first to the third scan lines 5130R, 5130G and 5130B.
[0900] [0900] In addition, in an exemplary embodiment, the contact positions of the respective 5020 epitaxial cells,
[0901] [0901] In an exemplary embodiment, an optically non-transmissive film can also be provided in the second insulation film 5083 or in the third insulation film 5085, in the fourth insulation film corresponding to the pixel. The optically non-transmissive film can be formed from a DBR dielectric mirror, a metal reflective film in an insulation film or an organic polymer film. When a metallic reflective film is used as an optically non-transmissive film it is manufactured in a floating state that is electrically isolated from components in other pixels. In an exemplary embodiment, the optically non-transmissive film can be formed by depositing two or more insulation films with different refractive indexes. For example, the optically non-transmissive film can be formed by stacking a material with a low refractive index and a material with a high refractive index in sequence, or alternatively, formed by insulation films stacked alternately with different refractive indexes from each other. . Materials with different refractive indexes are not particularly limited, but examples include SiO2 and SiNx.
[0902] [0902] As described above, in a display device, according to an exemplary embodiment, it is possible to stack sequentially a plurality of epitaxial cells and then form contacts with a spinning piece in a plurality of epitaxial cells at the same time.
[0903] [0903] FIG. 99 is a schematic plan view of a display apparatus, according to an exemplary embodiment, FIG. 100A is a partial cross-sectional view of FIG. 99, and FIG. 100B is a schematic circuit diagram.
[0904] [0904] Referring to FIGS. 99 and 100A, the display apparatus may include a substrate 6021, a plurality of pixels, a first stack of LED 6100, a second stack of LED 6200, a third stack of LED 6300, an insulation layer (or a buffer layer) 6130 with a multilayer structure, a first color filter 6230, a second color filter 6330, a first adhesive layer 6141, a second adhesive layer 6161, a third adhesive layer 6261 and a barrier 6350. In addition, the display device can include multiple pads and electrode connectors.
[0905] [0905] The substrate 6021 supports semiconductor batteries 6100, 6200 and 6300. In addition, the substrate 6021 can have a circuit in it. For example, substrate 6021 may be a silicon substrate on which thin film transistors are formed. TFT substrates are widely used to actively activate the matrix of a display field, as in an LCD display field or the like. Since a TFT substrate configuration is well known in the art, its detailed descriptions will be omitted. A plurality of pixels can be activated in an active matrix manner, but the inventive concepts are not limited to these. In another exemplary embodiment, substrate 6021 can include a passive circuit including data lines and scan lines and, therefore, the plurality of pixels can be passively driven in a matrix.
[0906] [0906] A plurality of cells can be arranged on the substrate 6021. The pixels can be separated from each other by a 6350 barrier. The 6350 barrier can be formed by a light reflecting material or a light absorbing material. The 6350 barrier can block light that travels to a neighboring pixel region by reflection or absorption, thereby preventing light interference between pixels. Examples of the light-reflecting material may include a light-reflecting material, such as a white photosensitive solder resistor (PSR), and examples of the light-absorbing material may include black epoxy or the like.
[0907] [0907] Each pixel includes the first to the third batteries of LED 6100, 6200 and 6300. The second battery of LED 6200 is disposed in the first battery of LED 6100 and the third battery of LED 6300 is disposed in the second battery of LED 6200.
[0908] [0908] The first stack of LED 6100 includes a semiconductor layer of type 6123 and a semiconductor layer of type p 6125, the second stack of LED 6200 includes a semiconductor layer of type 6223 and a semiconductor layer of type 6225 and the The third 6300 LED stack includes a n 6323 type semiconductor layer and a 6325 p type semiconductor layer. In addition, the first to the third 6100, 6200 and 6300 LED stack includes an active layer interposed between the 6123 n type semiconductor layer. , 6223 or 6323 and the semiconductor layer type p 6125, 6225 or 6325. The active layer may, in particular, have a multi-quantum well structure.
[0909] [0909] As an LED stack is positioned closer to the 6021 substrate, the LED stack can emit light with a longer wavelength. For example, the first 6100 LED battery can be an inorganic light emitting diode that emits red light, the second 6200 LED battery can be an inorganic light emitting diode that emits green light, and the third 6300 LED battery can be an inorganic LED emitting blue light. For example, the first 6100 LED stack can include an AlGaInP based well layer, the second 6200 LED stack can include an AlGaInP or AlGaInN based well layer and the third 6300 LED stack can include a well based layer in AlGaInN. However, inventive concepts are not limited to these. In particular, when the LED cells include micro LEDs, an LED cell positioned closer to the 6021 substrate can emit light with a shorter wavelength, and the LED cells disposed on it can emit light with a longer wavelength. no adverse affection operation or the need for color filters due to the small form factor of a micro LED.
[0910] [0910] An upper surface of each of the first to third LED batteries 6100, 6200 and 6300 can be of type n and a lower surface of it can be of type p. According to some exemplary modalities, however, the types of semiconductors on the top and bottom surfaces of each of the LED cells can be reversed.
[0911] [0911] When the top surface of the third 6300 LED stack is of type n, the top surface of the third 6300 LED stack can be textured by chemical engraving to form a rough surface (or irregularities). The top surface of the first 6100 LED stack and the second 6200 LED stack can also be roughened by surface textures. Meanwhile, when the second 6200 LED battery emits green light, since green light has greater visibility than red light or blue light, it is preferable to increase the light emission efficiency of the first 6100 LED battery and the third LED stack
[0912] [0912] The light generated in the first battery of LED 6100 can be transmitted through the second and third batteries of LED 6200 and 6300 and emitted to the outside. In addition, since the second 6200 LED battery emits light at a wavelength greater than the third 6300 LED battery, the light generated in the second 6200 LED battery can be transmitted through the third 6300 LED battery and emitted to the outside.
[0913] [0913] The first 6230 color filter can be disposed between the first 6100 LED stack and the second 6200 LED stack. In addition, the second 6330 color filter can be disposed between the second 6200 LED stack and the third stack 6300 LED filter. The first 6230 color filter transmits light generated in the first 6100 LED stack and reflects the light generated in the second LED stack.
[0914] [0914] In some exemplary embodiments, the first 6230 color filter can reflect the light generated in the third 6300 LED stack.
[0915] [0915] The first and second color filters 6230 and 6330 can be, for example, a low pass filter that passes through only a low frequency region, that is, a long wavelength region, a low pass filter. band that passes through only one band of predetermined wavelength, or a band interrupt filter that blocks only the band of predetermined wavelength. In particular, the first and second color filters 6200 and 6300 can be formed by alternately stacking the insulation layers with different refractive indices. For example, the first and second color filters 6200 and 6300 can be formed by alternately stacking TiO2 and SiO2. In particular, the first and second color filters 6200 and 6300 may include a distributed Bragg reflector (DBR). The interruption band of the distributed Bragg reflector can be controlled by adjusting the thicknesses of TiO2 and SiO2. The low-pass filter and the band-pass filter can also be formed by alternately stacking the insulation layers with different refractive indices.
[0916] [0916] The first adhesive layer 6141 is disposed between substrate 6021 and the first pile of LED 6100 and connects the first pile of LED 6100 to substrate 6021. The second adhesive layer 6161 is disposed between the first pile of LED 6100 and the second 6200 LED battery and connects the second 6200 LED battery to the first 6100 LED battery. In addition, the third adhesive layer 6261 is placed between the second 6200 LED battery and the third 6300 LED battery and connects the third LED battery 6300 to the second stack of
[0917] [0917] As shown, the second adhesive layer 6161 can be disposed between the first stack of LED 6100 and the first color filter 6230 and can contact the first color filter 6230. The second adhesive layer 6161 transmits light generated in the first 6100 LED stack.
[0918] [0918] The third adhesive layer 6261 can be placed between the second stack of LED 6200 and the second color filter 6330 and can contact the second color filter 6330. The second adhesive layer 6161 transmits light generated in the first pile of LED 6100 and the second LED stack 6200.
[0919] [0919] Each of the first to third adhesive layers 6141, 6161 and 6261 is formed by an adhesive material that can be standardized. Such adhesive layers 6141, 6161 and 6261 can include, for example, epoxy, polyimide, SU8, spin-on glass (SOG), benzocyclocyclobutene (BCB) or others, but are not limited to them.
[0920] [0920] A metal bonding material can be disposed in each of the adhesive layers 6141, 6161 and 6261, described in more detail below.
[0921] [0921] The 6130 insulation layer is disposed between the first adhesive layer 6141 and the first 6100 LED stack. The 6130 insulation layer has a multilayer structure and can include a first 6131 insulation layer in contact with the first LED stack. 6100 and a second insulation layer 6135 in contact with the first adhesive layer 6141. The first insulation layer 6131 can be formed by a silicon nitride film (SiNx layer) and the second insulation layer 6135 can be formed by a film of silicon oxide (SiO2 layer). As the silicon nitride film has a strong adhesive force to the GaP-based semiconductor layer and the SiO2 layer has a strong adhesive force to the first 6141 adhesive layer, the first 6100 LED stack can be stably attached to the 6021 substrate by stacking the silicon nitride film and the SiO2 layer.
[0922] [0922] According to an exemplary embodiment, a distributed Bragg reflector can also be disposed between the first insulation layer 6131 and the second insulation layer 6135. The distributed Bragg reflector prevents the light generated in the first 6100 LED stack absorbed into the substrate 6021, thus improving light efficiency.
[0923] [0923] In FIG. 100A, while the first adhesive layer 6141 is shown and described as being divided in each pixel unit by the barrier 6350, the first adhesive layer 6141 can be continuous across a plurality of pixels in some exemplary embodiments. The insulation layer 6130 can also be continuous across a plurality of pixels.
[0924] [0924] The first to third batteries of LED 6100, 6200 and 6300 can be electrically connected to a circuit on substrate 6021 using electrode pads, connectors and ohmic electrodes and therefore, for example, a circuit as shown in FIG. 100B can be implemented. The electrode pads, connectors and ohmic electrodes are described in more detail below.
[0925] [0925] FIG. 100B is a schematic circuit diagram of a display device according to an exemplary embodiment.
[0926] [0926] Referring to FIG. 100B, a drive circuit according to an exemplary embodiment can include two or more transistors Tr1 and Tr2 and a capacitor. When the power supply is connected to the selection lines Vrow1 to Vrow3 and a data voltage is applied to the data lines Vdata1 to Vdata3, a voltage is applied to the corresponding LED. In addition, the charges are charged to the corresponding capacitor according to the values of Vdata1 and Vdata3. An activation state of transistor Tr2 can be maintained by the charged voltage of the capacitor, and thus, even when the power is cut off at the selection line Vrow1, the voltage of the capacitor can be maintained and the voltage can be applied to the LEDs1 to LED3. In addition, the currents that flow through LED1 to LED3 can be changed according to the values from Vdata1 to Vdata3. The current can always be supplied by Vdd and, therefore, continuous light emission is possible.
[0927] [0927] Transistors Tr1 and Tr2 and capacitor can be formed on a substrate of 6021. Here, the light emitting diodes LED1 to LED3 can correspond to the first to third batteries of LEDs 6100, 6200 and 6300 stacked in one pixel, respectively . The anodes from the first to the third 6100, 6200 and 6300 LED batteries are connected to transistor Tr2 and their cathodes are grounded. The first to the third LED batteries 6100, 6200 and 6300 can be electrically grounded in common.
[0928] [0928] FIG. 100B shows an example for a circuit diagram for an active matrix drive, but other circuits for the active matrix drive can be used. In addition, according to an exemplary modality, passive driving of the matrix can also be implemented.
[0929] [0929] In the following, a method of manufacturing a display device will be described in detail.
[0930] [0930] FIGS. 101A to 107 are schematic plan views and cross-sectional views illustrating a method of manufacturing a display apparatus according to an exemplary embodiment. In each of the figures, the cross-sectional view is taken along the line shown in the corresponding plan view.
[0931] [0931] First, with reference to FIG. 101A, the first LED stack 6100 is grown on the first substrate 6121. The first substrate 6121 can be, for example, a GaAs substrate. The first 6100 LED stack is made up of semiconductor layers based on AlGaInP and includes a n 6123 type semiconductor layer, an active layer and a p 6125 type semiconductor layer. The first 6100 LED stack can have, for example, a composition of Al, Ga and In to emit red light.
[0932] [0932] The semiconductor layer type p 6125 and the active layer are engraved to expose the semiconductor layer type n
[0933] [0933] Referring to FIG. 101B, the ohmic contact layers 6127 and 6129 are formed. The ohmic contact layers 6127 and 6129 can be formed for each pixel region. The ohmic contact layer 6127 is in ohmic contact with the semiconductor layer of type 6123 and the ohmic contact layer 6129 is in ohmic contact with the semiconductor layer of type 6125. For example, the ohmic contact layer 6127 can include AuTe or AuGe, and the 6129 ohmic contact layer can include AuBe or
[0934] [0934] Referring to FIG. 101C, a 6130 insulation layer is formed in the first 6100 LED stack. The 6130 insulation layer has a multilayer structure and is patterned to have openings that expose the 6127 and 6129 ohmic contact layers. The 6130 insulation layer can include a first insulation layer 6131 and a second insulation layer 6135 and may also include a distributed Bragg reflector 6133. The second insulation layer 6135 can be incorporated into the distributed Bragg reflector 6133 as a part of the distributed Bragg reflector 6133.
[0935] [0935] The first insulation layer 6131 can include, for example, a silicon nitride film, and the second insulation layer 6135 can include a silicon oxide film. The silicon nitride film exhibits good adhesion properties to the AlGaInP-based semiconductor layer, but the silicon oxide film has low adhesion properties to the AlGaInP-based semiconductor layer. The silicon oxide film has good adhesion to the first adhesive layer 6141, which will be described below, while the silicon nitride film has poor adhesion properties to the first adhesive layer 6141. Like the silicon nitride film and the oxide film of silicon exhibit mutually complementary voltage characteristics, it is possible to improve the stability of the process using the silicon nitride film and the silicon oxide film together, thus preventing the occurrence of defects.
[0936] [0936] While the ohmic contact layers 6127 and 6129 are described as being formed first and the insulation layer 6130 is formed from then on, according to some exemplary embodiments, the insulation layer 6130 can be formed first and the layers of ohmic contact 6127 and 6129 can be formed in the openings of the insulation layer 6130 which expose the semiconductor layer of the type 6123 and the semiconductor layer of the type 6125.
[0937] [0937] Referring to FIG. 101D, subsequently, the first electrode pads 6137, 6138, 6139 and 6140 are formed. The first electrode pads 6137 and 6139 are connected to the ohmic contact layers 6127 and 6129 through the openings of the insulation layer 6130, respectively. The first 6138 and 6140 electrode pads are disposed in the 6130 insulation layer and are isolated from the first 6100 LED stack. As described below, the first 6138 and 6140 electrode pads will be electrically connected to the type 6225 and 6325 semiconductor layers of the second battery of LED 6200 and third battery of LED 6300, respectively. The first 6137, 6138, 6139 and 6140 electrode pads may have a multilayer structure and, particularly, may include a metal barrier layer on their upper surface.
[0938] [0938] Referring to FIG. 101E, a first adhesive layer 6141 is then formed on the first electrode pads 6137, 6138, 6139 and 6140. The first adhesive layer 6141 can contact the second insulation layer 6135.
[0939] [0939] The first adhesive layer 6141 is standardized to have openings that expose the first electrode pads 6137, 6138, 6139 and 6140. As such, the first adhesive layer 6141 is formed by a material that can be standardized and can be formed, for example, by epoxy, polyimide, SU8, SOG, BCB or others.
[0940] [0940] Metal bonding materials 6143 that have substantially a sphere shape are formed in the openings of the first adhesive layer 6141. The metal bonding material
[0941] [0941] Referring to FIG. 102A, subsequently, the substrate 6021 and the first stack of LED 6100 are connected. Electrode pads 6027, 6028, 6029 and 6030 are arranged on substrate 6021 in correspondence with the first electrode pads 6137, 6138, 6139 and 6140, and metal bonding materials 6143 connect the first electrode pads 6137, 6138, 6139 and 6140 with electrode pads 6027, 6028, 6029 and 6030. In addition, the first adhesive layer 6141 bonds substrate 6021 and insulation layer 6130.
[0942] [0942] Substrate 6021 can be a glass substrate on which a thin film transistor is formed, a Si substrate on which a CMOS transistor is formed, or others, for active activation of the matrix.
[0943] [0943] While the first electrode pads 6137 and 6139 are shown as spaced from the ohmic contact layers 6127 and 6129, the first electrode pads 6137 and 6139 are electrically connected to the ohmic contact layers 6127 and 6129 through the insulation layer 6130 , respectively.
[0944] [0944] Although the first adhesive layer 6141 and the metal bonding materials 6143 are described as being formed on the first side of the substrate 6121, the first adhesive layer 6141 and the metal bonding materials 6143 can be formed on the side of the substrate 6021, or adhesive layers can be formed on the first side of substrate 6121 and on the side of substrate 6021, respectively, and these adhesive layers can be bonded together.
[0945] [0945] Metal bonding materials 6143 are pressed by these pads between the first electrode pads 6137, 6138, 6139 and 6140, and the electrode pads 6027, 6028, 6029 and 6030 on the substrate 6021 and thus the surfaces upper and lower are deformed to have a flat shape, according to the shape of the electrode pads. Since the metal bonding materials 6143 are deformed in the openings of the first adhesive layer 6141, the metal bonding materials 6143 can substantially completely fill the openings of the first layer of adhesive 6141 to be in close contact with the first layer of adhesive 6141, or an empty space can be formed in the openings of the first adhesive layer 6141. The first adhesive layer 6141 can contract in the vertical direction and can expand in the horizontal direction under heating and pressurizing conditions, and thus a shape of an inner wall the openings may be deformed.
[0946] [0946] The shapes of the metal connecting elements 6143 and the first adhesive layer 6141 are described below with reference to FIGS. 108A, 108B and 108C.
[0947] [0947] Referring to FIG. 102B, the first substrate 6121 is removed and the semiconductor layer type n 6123 is exposed. The first 6121 substrate can be removed using a wet etching technique or the like. A surface roughened by surface texturing can be formed on the surface of the exposed 612 semiconductor layer.
[0948] [0948] Referring to FIG. 102C, the H1 holes that pass through the first LED stack 6100 and the insulation layer 6130 can be formed using a hard mask or the like. H1 holes can expose the first electrode pads 6137, 6138 and 6140, respectively. The H1 hole is not formed in the first 6139 electrode pad and therefore the first 6139 electrode pad is not exposed through the first LED stack
[0949] [0949] Next, a 6153 insulation layer is formed to cover the surface of the first 6100 LED stack and the side walls of the H1 holes. The insulation layer 6153 is standardized to expose the first electrode pads 6137, 6138, 6139 and 6140 in the H1 holes. The insulation layer 6153 can include a silicon nitride film or a silicon oxide film.
[0950] [0950] Referring to FIG. 102D, first connectors 6157, 6158 and 6160 that are electrically connected to the first electrode pads 6137, 6138 and 6140 through holes H1, respectively, are formed.
[0951] [0951] The first connector 6157 is connected to the first pad of electrodes 6137, the first connector 2 6158 is connected to the first pad of electrodes 6138 and the first connector 3 6160 is connected to the first pad of electrodes 6140. The first pad of electrodes 6140 is electrically connected to the n 6123 type semiconductor layer of the first 6100 LED stack and therefore the first 6157 connector is also electrically connected to the n 6123 type semiconductor layer. The first 2 6158 connector and the first 6160 3 connector are isolated electrically from the first 6100 LED battery.
[0952] [0952] Referring to FIG. 102E, a second adhesive layer 6161 is then formed on the first connectors 6157, 6158 and 6160.
[0953] [0953] The second adhesive layer 6161 is patterned to have openings that expose the first connectors 6157, 6158 and 6160. As such, the second adhesive layer 6161 is formed by a material that can be patterned in a similar way to the first adhesive layer 6141 and it can be formed by, for example, epoxy, polyimide, SU8, SOG, BCB or others.
[0954] [0954] Metal bonding materials 6163 having substantially a sphere shape are formed in the openings of the second adhesive layer 6161. The material and shape of the metal bonding material 6163 are similar to those of the metal bonding material 6143 described above and therefore detailed descriptions of it are omitted.
[0955] [0955] Referring to FIG. 103A, the second LED stack 6200 is grown on a second substrate 6221 and a second transparent electrode 6229 is formed on the second LED stack 6200.
[0956] [0956] The second substrate 6221 can be a substrate capable of increasing the second stack of LED 6200, for example, a sapphire substrate or a GaAs substrate.
[0957] [0957] The second LED stack 6200 can be formed from semiconductor layers based on AlGaInP or semiconductor layers based on AlGaInN. The second LED stack 6200 may include a semiconductor layer type n 6223, a semiconductor layer type p 6225 and an active layer, and the active layer may have a multi-quantum well structure. A composition ratio of the well layer to the active layer can be determined so that the second 6200 LED stack emits green light, for example.
[0958] [0958] The second transparent electrode 6229 is in ohmic contact with the p-type semiconductor layer. The second transparent electrode 6229 can be formed by a metal layer or a conductive oxide layer that is transparent to red light and green light. Examples of the conductive oxide layer can include SnO2, InO2, ITO, ZnO, IZO or others.
[0959] [0959] Referring to FIG. 103B, the second transparent electrode 6229, the semiconductor layer type p 6225 and the active layer are standardized to partially expose the semiconductor layer type n 6223. The semiconductor layer type n 6223 will be exposed in a plurality of regions corresponding to a plurality of pixel regions on the second substrate 6221.
[0960] [0960] Although the semiconductor type n 6223 layer is described as being exposed after the formation of the second transparent electrode 6229, in some exemplary embodiments, the semiconductor type n 6223 layer can be exposed first and the second transparent electrode 6229 can be formed posteriorly.
[0961] [0961] Referring to FIG. 103C, a first 6230 color filter is formed on the second transparent electrode 6229. The first 6230 color filter is formed to transmit light generated in the first 6100 LED stack and to reflect the light generated in the second 6200 LED stack.
[0962] [0962] Then, a 6231 insulation layer can be formed on the first 6230 color filter. The 6231 insulation layer can be formed to control stress and can be formed, for example, by a silicon nitride film (SiNx) or a silicon oxide (SiO2) film. Insulation layer 6231 can be formed first before forming the first color filter
[0963] [0963] The openings that expose the type 6 semiconductor layer 6223 and the second transparent electrode 6229 are formed by standardizing the insulation layer 6231 and the first color filter 6230.
[0964] [0964] Although the first 6230 color filter is described as being formed after the type 6 6223 semiconductor layer is exposed, according to some exemplary embodiments, the first 6230 color filter can be formed first and then the first color filter 6230, the second transparent electrode 6229, the semiconductor layer type p 6225 and the active layer can be standardized to expose the semiconductor layer type n 6223. Then, the insulation layer 6231 can be formed to cover side surfaces of the semiconductor layer type p 6225 and the active layer.
[0965] [0965] Referring to FIG. 103D, subsequently, the second electrode pads 6237, 6238 and 6240 are formed on the first color filter 6230 or on the insulation layer 6231. The second electrode pad 6237 can be electrically connected to the semiconductor layer type n 6223 by opening the the first color filter 6230 and the second electrode pad 6238 can be electrically connected to the second transparent electrode 6229 through the opening of the first color filter 6230. The second electrode pad 6240 is arranged on the first color filter 6240 and is isolated from the second 6200 LED stack.
[0966] [0966] With reference to FIG. 104A, the second LED stack 6200 and the second electrode pads 6237, 6238 and 6240 which are described with reference to FIG. 103D, are coupled to the second adhesive layer 6161 and to the metal bonding materials 6163 which are described with reference to FIG. 102E. The metal bonding materials 6163 can connect the first connectors 6157, 6158 and 6160 and the second electrode pads 6237, 6238 and 6240,
[0967] [0967] The second substrate 6221 is separated from the second stack of LED 6200 and the surface of the second stack of LED 6200 is exposed. The second 6221 substrate can be separated using a technique such as chemical attack, laser removal or the like. A rough surface by surface texturing can be formed on the surface of the exposed second LED stack 6200, that is, the surface of the n 6223 type semiconductor layer.
[0968] [0968] Although the second adhesive layer 6161 and the metal bonding materials 6163 are described as being formed in the first stack of LED 6100 to connect the second stack of LED 6200, according to some exemplary embodiments, the second layer of adhesive 6161 and metal bonding materials 6163 can be formed on the second side of the LED stack
[0969] [0969] With reference to FIG. 104B, the H2 holes that pass through the second LED stack 6200, the second transparent electrode 6229, the first color filter 6230 and the insulation layer 6231 can be formed using a rigid mask or the like. H2 holes can expose second electrode pads 6237 and 6240, respectively. Hole H2 is not formed in the second electrode pad 238 and therefore the second electrode pad 238 is not exposed through the second battery of
[0970] [0970] Next, an insulation layer 6253 is formed to cover the surface of the second stack of LED 6200 and the side walls of the H2 holes. The insulation layer 6253 is standardized to expose the second electrode pads 6237 and 6240 in the H2 holes. The insulation layer 6253 may include a silicon nitride film or a silicon oxide film.
[0971] [0971] With reference to FIG. 104C, the second connectors 6257 and 6260 that are electrically connected to the second electrode pads 6237 and 6240 through holes H2, respectively, are formed. The second connector 1 6257 is connected to the second electrode 6237 and therefore electrically connected to the semiconductor layer of type n 6223. The second connector 2 6260 is isolated from the second battery of LED 6200 and isolated from the first battery of LED 6100.
[0972] [0972] In addition, the second connector 1 6257 is electrically connected to the electrode pad 6027 through the first connector 1 6157 and the second connector 2 6260 is electrically connected to the electrode pad 6030 through the first connector 3 6160. The second connector 1 6257 can be stacked in a vertical direction to the first connector 1 6157 and the second connector 2 6260 can be stacked in a vertical direction to the first connector 3 6160. However, the inventive concepts are not limited to these.
[0973] [0973] With reference to FIG. 104D, a third adhesive layer 6261 is then formed in the second connectors 6257 and 6260. The third adhesive layer 6261 can contact the insulation layer 6253.
[0974] [0974] The third adhesive layer 6261 is standardized to have openings that expose the second connectors 6257 and 6260. As such, the third adhesive layer 6261 is formed by a material that can be patterned in a similar way to the first adhesive layer 6141 and can be formed, for example, by epoxy, polyimide, SU8, SOG, BCB or others.
[0975] [0975] Metal bonding materials 6263 having substantially a sphere shape are formed in the openings of the third adhesive layer 6261. The material and shape of the metal bonding material 6263 are similar to those of the metal bonding material 6143 described above and therefore detailed descriptions of it are omitted.
[0976] [0976] With reference to FIG. 105A, the third 6300 LED stack is grown on a third 6321 substrate and a third transparent 6329 electrode is formed on the third LED stack
[0977] [0977] The third substrate 6321 can be a substrate capable of growing the third stack of LED 6300, for example, a sapphire substrate. The third 6300 LED stack can be formed by layers of semiconductors based on AlGaInN. The third 6300 LED stack can include a n 6323 type semiconductor layer, a p 6325 type semiconductor layer and an active layer, and the active layer can have a multi-quantum well structure. A composition ratio of the well layer to the active layer can be determined so that the third 6300 LED stack emits blue light, for example.
[0978] [0978] The third transparent electrode 6329 is in ohmic contact with the semiconductor type p 6325. The third transparent electrode 6329 can be formed by a metal layer or a layer of conductive oxide that is transparent to red light, green light and blue light. Examples of the conductive oxide layer can include SnO2, InO2, ITO, ZnO, IZO or others.
[0979] [0979] With reference to FIG. 105B, the third transparent electrode 6329, the semiconductor layer type p 6325 and the active layer are standardized to partially expose the semiconductor layer type n 6323. The semiconductor layer type n 6323 will be exposed in a plurality of regions corresponding to a plurality of pixel regions on the third substrate 6321.
[0980] [0980] Although the semiconductor type n 6323 layer is described as being exposed after the formation of the third transparent electrode 6329, according to some exemplary embodiments, the semiconductor layer type n 6323 can be exposed before the first and the third transparent electrode 6329 can be formed.
[0981] [0981] With reference to FIG. 105C, a second 6330 color filter is formed on the third transparent electrode 6329. The second 6330 color filter is formed to transmit light generated in the first 6100 LED battery and the second 6200 LED battery and to reflect the light generated in the third battery 6300 LED.
[0982] [0982] Then, an insulation layer 6331 can be formed on the second color filter 6330. The insulation layer 6331 can be formed to control stress and can be formed, for example, by a silicon nitride film (SiNx) or a silicon oxide (SiO2) film. The insulation layer 6331 can be formed first before the formation of the second color filter 6330. Meanwhile, openings that expose the type 6 semiconductor layer 6323 and the second transparent electrode 6329 are formed by standardizing the insulation layer 6331 and the second filter of color 6330.
[0983] [0983] Although the second color filter 6330 is described as being formed after the semiconductor layer of type n 6323 is exposed, according to some exemplary modalities,
[0984] [0984] With reference to FIG. 105D, subsequently, the third electrode pads 6337 and 6340 are formed on the second color filter 6330 or on the insulation layer 6331. The third electrode pad 6337 can be electrically connected to the semiconductor layer type n 6323 by opening the second filter color 6330, and the third electrode pad 6340 can be electrically connected to the third transparent electrode 6329 through the opening of the second color filter 6330.
[0985] [0985] With reference to FIG. 106A, the third 6300 LED stack and the third electrode pads 6337 and 6340 which are described with reference to FIG. 105D, are attached to the third adhesive layer 6261 by the metal bonding materials 6263 which are described with reference to FIG. 104E. The metal connection materials 6263 can connect the second connectors 6257 and 6260 and the third electrode pads 6337 and 6340, respectively, and the third adhesive layer 6261 can connect the insulation layer 6331 and the insulation layer 6253. The connection using the third adhesive layer 6261 and the metal bonding materials 6263 is similar to that described with reference to FIG. 102A and therefore their detailed descriptions are omitted.
[0986] [0986] The third substrate 6321 is separated from the third 6300 LED stack and the surface of the third 6300 LED stack is exposed. The third 6321 substrate can be separated using a technique such as laser removal, chemical removal or others. A rough surface by surface texturing can be formed on the surface of the third exposed 6300 LED stack, that is, the surface of the n 6323 type semiconductor layer.
[0987] [0987] Although the third adhesive layer 6261 and the metal bonding materials 6263 are described as being formed in the second LED stack 6200 to connect the third LED stack 6300, according to some exemplary embodiments, the third adhesive layer 6261 and metal bonding materials 6263 can be formed on the side of the third stack of LED 6300. In addition, an adhesive layer can be formed on the second stack of LED 6200 and the third stack of LED 6300, respectively, and these adhesive layers can be formed connected to each other.
[0988] [0988] With reference to FIG. 106B, subsequently, regions between adjacent pixels are then recorded to separate the pixels, and an insulating layer 6341 can be formed. The insulating layer 6341 can cover a side surface and an upper surface of each pixel. A region between adjacent pixels can be removed to expose the substrate 6021, but the inventive concepts are not limited to these. For example, the first adhesive layer 6141 can be formed continuously over a plurality of pixel regions without being separated, and the insulation layer 6130 can also be continuous.
[0989] [0989] With reference to FIG. 107, subsequently, a 6350 barrier can be formed in a region of separation between the pixel regions. The 6350 barrier can be formed by a light reflecting layer or a light absorbing layer and, therefore, light interference between pixels can be avoided. The light reflecting layer may include, for example, a white PSR, a distributed Bragg reflector, an insulation layer such as SiO2 and a reflective metal layer deposited on it, or a highly reflective organic layer. For a light blocking layer, black epoxy, for example, can be used.
[0990] [0990] Thus, a display device, according to an exemplary embodiment, in which a plurality of pixels are arranged on the substrate 6021, can be provided. The first to third batteries of LED 6100, 6200 and 6300 in each pixel can be triggered independently by the power input through the electrode pads 6027, 6028, 6029 and 6030.
[0991] [0991] FIGS. 108A, 108B and 108C are schematic cross-sectional views of metal bonding materials 6143, 6163 and
[0992] [0992] With reference to FIG. 108A, metal bonding materials 6143, 6163 and 6263 are arranged in the openings of the first to third adhesive layers 6141, 6161 and 6261. A lower surface of metal bonding materials 6143, 6163 and 6263 is in contact with the electrode 6030 or connector 6160 or 6260 and therefore metal bonding materials 6143, 6163 and 6263 can have a substantially flat shape depending on an upper surface shape of the electrode pads or connectors. The upper surfaces of the metal bonding materials 6143, 6163 and 6263 can be substantially flat in shape, depending on the shape of the electrode pads 6140, 6240 and 6340. A side surface of the metal bonding materials 6143, 6163 and 6263 can have a substantially curved shape. A central portion of the metal bonding materials 6143, 6163 and 6263 may be outwardly convex in shape.
[0993] [0993] An internal wall of the adhesive layer openings
[0994] [0994] With reference to FIG. 108B, the shapes of the metal bonding materials 6143, 6163 and 6263 and the adhesive layers 6141, 6161 and 6261, according to an exemplary embodiment, are substantially similar to those described with reference to FIG. 108A, but there is a difference in that a convex portion of the side surface is arranged in a relatively lower position by heating.
[0995] [0995] With reference to FIG. 108C, the shapes of the metal bonding materials 6143, 6163 and 6263, according to an exemplary embodiment, are similar to those described with reference to FIG. 108B, but are different from the shapes of the inner walls of the adhesive layer openings 6141, 6161 and
[0996] [0996] Although certain exemplary modalities and implementations have been described here, other modalities and modifications will be evident from this description. Therefore, the inventive concepts are not limited to these modalities, but to the broader scope of the appended claims and to several obvious modifications and equivalent arrangements, as would be evident to a person skilled in the art.

权利要求:
Claims (20)
[1]
1. Light-emitting device, comprising: a first LED subunit; a second LED subunit arranged below the first LED subunit; a third LED subunit arranged below the second LED subunit; an insulation layer that substantially covers the first, second and third LED subunits; and electrode pads electrically connected to the first, second and third LED subunits, the electrode pads comprising a common electrode pad, a first electrode pad, a second electrode pad and a third electrode pad, where: the third LED subunit is arranged in a partial region of the second LED subunit; the second LED subunit is arranged in a partial region of the third LED subunit; the insulation layer has openings for electrical connection between the electrodes; the common electrode pad is connected to the first, second and third LED subunits through the openings in the insulation layer; the first, second and third electrode pads are connected to the first, second and third LED subunits, respectively, through at least one of the openings; and the first, second and third LED subunits are configured to operate independently using the electrodes.
[2]
2. Light-emitting device according to claim 1, characterized in that: the light generated in the first LED subunit is configured to be emitted outside the light emitting device through the second LED subunit and the third LED subunit ; and the light generated in the second LED subunit is configured to be emitted to the outside of the light emitting device through the third LED subunit.
[3]
Light emitting device according to claim 2, characterized in that the first, second and third LED subunits comprise the first, second and third LED batteries configured to emit red light, green light and blue light, respectively.
[4]
Light-emitting device according to claim 2, characterized in that the light-emitting device comprises a micro-emitting diode having a surface area of less than about 10,000 µm square.
[5]
5. Light-emitting device, according to claim 4, characterized by: the first LED subunit is configured to emit any red, green and blue light; the second LED subunit is configured to emit a light other than red, green and blue from the first LED subunit; and a third LED subunit is configured to emit a different red, green and blue light from the first and second LED subunits.
[6]
6. Light-emitting device according to claim 1, further comprising: a first transparent electrode interposed between the first LED subunit and the second LED subunit and in ohmic contact with a lower surface of the second LED subunit; a second transparent electrode interposed between the second LED subunit and the third LED subunit and in ohmic contact with a lower surface of the second LED subunit; and a third transparent electrode arranged to be in ohmic contact with an upper surface of the third LED subunit, in which at least some of the openings in the insulation layer expose the first, second and third pads of transparent electrodes.
[7]
7. Light-emitting device according to claim 6, characterized in that one of the openings in the insulation layer exposes the second transparent electrode and the third transparent electrode together.
[8]
Light-emitting device according to claim 7, characterized in that: the first, second and third LED subunits comprise a first conductivity-type semiconductor layer and a second conductivity-type semiconductor layer; the first, second and third pads of transparent electrodes are electrically connected to the second conductivity type semiconductor layers of the first, second and third LED subunits, respectively; and
[9]
Light-emitting device according to claim 8, characterized in that the first LED subunit and the second LED subunit are arranged in an upper region of the second conductivity type semiconductor layer of the third LED subunit.
[10]
Light-emitting device according to claim 8, characterized in that the second and third electrode pads are electrically connected to the first conductivity type semiconductor layer of the second LED subunit and to the first conductivity type semiconductor layer of the third subunit LED, respectively.
[11]
11. Light-emitting device according to claim 9, characterized in that the second and third electrode pads are directly connected to the first conductivity type semiconductor layers of the second LED subunit and the third LED subunit, respectively.
[12]
Light emitting device according to claim 6, further comprising: a first colored filter disposed between the third transparent electrode and the second transparent electrode; and a second color filter with a refractive index different from the first color filter and disposed between the second LED subunit and the first transparent electrode pad.
[13]
Light-emitting device according to claim 12, further comprising: a first bonding layer interposed between the first color filter and the second transparent electrode; and a third bond layer interposed between the second color filter and the first transparent electrode.
[14]
Light emitting device according to claim 1, further comprising: a substrate connected to a lower surface of the third LED subunit, wherein the substrate comprises at least one of a sapphire material and a nitride material of gallium.
[15]
15. Light-emitting device according to claim 1, characterized in that the second LED subunit and the third LED subunit are connected in common through one of the openings in the insulation layer.
[16]
16. Light-emitting device according to claim 1, characterized by further comprising an ohmic electrode disposed between the electrode pads and the first LED subunit and in ohmic contact with the first LED subunit, in which: the first pad electrode is connected to the ohmic electrode; and the insulating layer comprises at least one of a light reflecting layer and a light absorbing layer.
[17]
17. Display apparatus comprising: a circuit board with a drive circuit for driving light emitting devices in an active matrix drive mode or passive matrix drive mode; and a plurality of light emitting devices fitted to the circuit board, at least some of the light emitting devices comprise the light emitting device according to claim 1, wherein the electrode pads are electrically connected to the circuit board.
[18]
18. Apparatus according to claim 17, characterized in that: the light-emitting devices comprise the respective substrates connected to the third LED subunit; and the substrates are spaced apart.
[19]
19. Light-emitting stacked structure, characterized by comprising: a substrate including an upper surface and a lower surface; a plurality of sequentially stacked epitaxial subunits arranged on the substrate and configured to emit light of different wavelength bands, each epitaxial subunit has a light-emitting region that overlaps the light-emitting region of an adjacent epitaxial subunit; and a substantially non-transmissive film covering at least a portion of the lateral surfaces of the epitaxial subunits, wherein the lateral surfaces of the epitaxial subunits are inclined with respect to one of the upper and lower surfaces of the substrate.
[20]
20. Light emitting diode (LED) stack for a display, characterized by comprising: a first LED subunit; a second LED subunit arranged in the first LED subunit; a third LED subunit arranged in the second LED subunit; a connector disposed on at least one side surface of the first, second and third LED subunits and electrically connected to at least one of the LED subunits; and an insulating layer to insulate the connector from at least one side surface of the LED subunits, wherein: the at least one side surface of the LED subunits is inclined with respect to a lower surface of one of the first, second and third subunits LED; and the connector is arranged on the sloping side surface of the LED subunits.

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引用文献:

---

公开号 | 申请日 | 公开日 | 申请人 | 专利标题

---

---

JP3259931B2|1992-04-17|2002-02-25|シャープ株式会社|Semiconductor light emitting device and semiconductor display device|

---

US5703436A|1994-12-13|1997-12-30|The Trustees Of Princeton University|Transparent contacts for organic devices|

---

US5583349A|1995-11-02|1996-12-10|Motorola|Full color light emitting diode display|

---

KR100298205B1|1998-05-21|2001-08-07|오길록|Integrated tri-color light emitting diode and method for fabricating the same|

---

JP2005072323A|2003-08-26|2005-03-17|Oki Data Corp|Semiconductor device|

---

JP2007095844A|2005-09-27|2007-04-12|Oki Data Corp|Semiconductor light-emitting composite device|

---

JP5030742B2|2006-11-30|2012-09-19|株式会社半導体エネルギー研究所|Light emitting element|

---

JP2008263127A|2007-04-13|2008-10-30|Toshiba Corp|Led apparatus|

---

KR101332794B1|2008-08-05|2013-11-25|삼성전자주식회사|Light emitting device, light emitting system comprising the same, and fabricating method of the light emitting device and the light emitting system|

---

JP5097057B2|2008-08-29|2012-12-12|株式会社沖データ|Display device|

---

JP5854419B2|2011-03-18|2016-02-09|国立大学法人山口大学|Multi-wavelength light emitting device and manufacturing method thereof|

---

TW201438188A|2013-03-25|2014-10-01|Miracle Technology Co Ltd|Stacked LED array structure|

---

KR101452801B1|2014-03-25|2014-10-22|광주과학기술원|Light emitting diode and method for manufacturing thereof|

---

JP6413460B2|2014-08-08|2018-10-31|日亜化学工業株式会社|LIGHT EMITTING DEVICE AND LIGHT EMITTING DEVICE MANUFACTURING METHOD|

---

KR20170115142A|2016-04-04|2017-10-17|삼성전자주식회사|Led lighting source module and display apparatus|JP2019120844A|2018-01-10|2019-07-22|キヤノン株式会社|Display device and imaging apparatus|

---

KR20190098308A|2018-02-13|2019-08-22|삼성디스플레이 주식회사|Method for fabricating thin film transistor substrate|

---

US10879419B2|2018-08-17|2020-12-29|Seoul Viosys Co., Ltd.|Light emitting device|

---

KR20200070901A|2018-12-10|2020-06-18|삼성전자주식회사|Display module, display apparatus including the same and method of manufacturing display module|

---

US10971650B2|2019-07-29|2021-04-06|Lextar Electronics Corporation|Light emitting device|

---

US11038088B2|2019-10-14|2021-06-15|Lextar Electronics Corporation|Light emitting diode package|

---

US20210126174A1|2019-10-28|2021-04-29|Seoul Viosys Co., Ltd.|Light emitting device for display and led display apparatus having the same|

---

US20210202815A1|2019-12-28|2021-07-01|Seoul Viosys Co., Ltd.|Light emitting device and led display apparatus having the same|

---

CN113556882A|2020-04-23|2021-10-26|鹏鼎控股股份有限公司|Manufacturing method of transparent circuit board and transparent circuit board|

---

CN214672654U|2020-06-03|2021-11-09|首尔伟傲世有限公司|Light emitting element module and display device including the same|

---

CN111697122A|2020-07-13|2020-09-22|东莞市中麒光电技术有限公司|Display module and manufacturing method thereof, LED display module and LED display screen|

---

CN112736169A|2021-03-30|2021-04-30|北京芯海视界三维科技有限公司|Light emitting device and display apparatus|

法律状态:
2021-12-07| B350| Update of information on the portal [chapter 15.35 patent gazette]|

优先权:

---

申请号 | 申请日 | 专利标题

---

US201762608297P| true| 2017-12-20|2017-12-20|

---

US62/608,297|2017-12-20|

---

US201862613333P| true| 2018-01-03|2018-01-03|

---

US62/613,333|2018-01-03|

---

US201862614900P| true| 2018-01-08|2018-01-08|

---

US62/614,900|2018-01-08|

---

US201862638797P| true| 2018-03-05|2018-03-05|

---

US62/638,797|2018-03-05|

---

US201862683564P| true| 2018-06-11|2018-06-11|

---

US201862683553P| true| 2018-06-11|2018-06-11|

---

US62/683,553|2018-06-11|

---

US62/683,564|2018-06-11|

---

US16/198,850|2018-11-22|

---

US16/198,850|US20190189596A1|2017-12-20|2018-11-22|Led unit for display and display apparatus having the same|

---

PCT/KR2018/016170|WO2019124952A1|2017-12-20|2018-12-19|Led unit for display and display apparatus having the same|

---