• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
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  • 优先权
    • 专利摘要:
    Semiconductor device, comprising a substrate (40), metallized contacts (30, 32), a succession of regions (10) formed by highly misaligned semiconductor alloys in a network, arranged one after another and with opposite doped types between adjacent regions, and carrier blocking regions (20, 22) with the same type of doping and located at both ends of the succession of regions (10). The succession of regions (10) may comprise a first region (12) with a first semiconductor of a highly network mismatched alloy with doping of a first type, a second region (14) with a second semiconductor of a highly network mismatched alloy with doping of a second type as opposed to the first type, optionally, a third region (16) with a third semiconductor of a highly network mismatched alloy with a doping like that of the first type, so on can increase the number of regions. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2810599A1
    申请号:ES201930783
    申请日:2019-09-06
    公开日:2021-03-08
    发明作者:MARTÍNEZ Mª NAIR LÓPEZ；Carretero Basilio Javier García；De Cal Alejandro Braña；Palazón José Luis Castaño
    申请人:Universidad Autonoma de Madrid；
    IPC主号:
    专利说明:

    [0003] Technical field of the invention
    [0005] The present invention relates to solid state physics and belongs to the field of semiconductor electronics. Its applications are diverse and cover telecommunications (detection of signals from ultraviolet to infrared, emission of ultraviolet, visible or infrared light), medicine (tissue temperature sensor), photovoltaic solar energy (multi-junction solar cells without the need for creation tunnel junctions, multi-band forbidden solar cells), microelectronic devices (variable resistors), among others.
    [0007] Background of the invention
    [0009] Knowledge of semiconductor physics has allowed the creation of new electronic devices such as semiconductor diodes, transistors, amplifiers, thyristors, operational amplifiers, among others. Microelectronics has allowed technological advancement and is currently present in all electronic devices: radios, televisions, computers, audio and video players, tomographs, mobile phones, solar cells, etc.
    [0011] Within microelectronics, diodes are currently made up of a single bandgap semiconductor material doped to create a region containing negatively charged carriers (n-type semiconductor, electrons) and a region doped with positively charged carriers ( p-type semiconductor, holes) creating a pn junction between both regions. The junction between both regions is called the space charge region. The diode conducts a current of electrons from the n side to the p side known as the electron diffusion current. The difference in carriers between zone n and zone p generates an electric field that acts on the free electrons in zone n giving rise to a displacement force that is opposite to the movement of the electrons. When we subject the diode to an external potential, a potential difference is produced between the area n and p, being able to polarize the diode in direct or inverse. Currently known conventional diodes allow the passage of current under conditions of forward polarization, with only a minimal leakage current in the case of reverse polarization.
    [0012] The transistor is a semiconductor electronic device used to deliver an output signal in response to an input signal. On a double diode structure in phase contrast, that is, two bipolar junctions ( pnp or npn), a structure with triple connection is generated where: the emitter emits carriers, the collector that receives or collects them and the third, which is interleaved between the first two, it modulates the passage of said carriers (base). It is a current-controlled active device that returns an amplified current.
    [0014] The state of the art regarding the photovoltaic field, has as one of its main objectives, the creation of new photovoltaic materials that reduce the cost in order to make solar energy a competitive source of electrical energy in the market. An efficient use of the full solar spectrum, ranging from near infrared to ultraviolet, is therefore one of the main challenges for solar energy conversion technologies, thus allowing better use of the photons emitted by the Sun with an increase in the photocurrent of the semiconductor device.
    [0016] In a first stage, in order to achieve cost reductions in the manufacture of photovoltaic (PV) solar cells, the researchers worked on the design of high-quality solar cells that could increase the efficiency of the semiconductor layers by reducing impurities. in the material, the material used in this first generation of solar cells was silicon. The conversion efficiency of a solar cell is limited by the trade-off between the open circuit voltage and the photocurrent draw from the cell. The semiconductor with which the photovoltaic device is made converts the absorbed photons into electrical current. These absorbed photons promote electrons from the valence band (VB) to the conduction band (CB) creating an electron-hole pair. As is well known, under illumination and polarization conditions, a separation of the pseudo Fermi levels occurs, forming an electric field that promotes the transport of the carriers to the contacts of the semiconductor device. The open circuit voltage will be set by the Fermi pseudo-levels that are limited by the bandwidth of the semiconductor. However, photocurrent extraction is proportional to the number of photons that can be absorbed by the semiconductor, in which case a smaller bandwidth would correspond to an increase in the photon absorption spectrum. The theoretical maximum limit was calculated by Shockley and Quiesser which describes the behavior of diodes in a single spectral region. As a consequence of this limitation, the maximum theoretical conversion limit for cells with a single band prohibited is 40.7%, being known as first photovoltaic generation. This first generation of solar cells is mainly based on monocrystalline Si. In order to improve the performance of semiconductor devices, engineering layers were used as window layers, or back surface field ( BSF) layers, mono texture, and so on.
    [0018] The second generation of solar cells was born in order to lower costs within photovoltaic energy, in this sense two lines were proposed: 1) use of less efficient materials, but cheaper to generate thin films and 2) solar concentrators. Solar cells were designed to work under high concentrations of solar radiation. In this way, the area of the photovoltaic materials used is reduced and the front surface of the cell is covered with solar concentrators that can increase the density of photons absorbed by the cell, increasing the photocurrent of the semiconductor device. Solar concentrators are based on lenses and mirrors, which have a lower cost than photovoltaic material. In this way, they reduce the total cost of the system as well as an increase in the efficiency of the cell as a consequence of the high concentration. On the other hand, the second generation was also based on materials that made it possible to lower costs by generating thin films. Thin film technology was suggested as a low cost alternative, because of the high absorption coefficient of the semiconductors used, so it requires much less semiconductor material. Some examples are: cadmium telluride (CdTe), amorphous silicon (a Si) or indium-copper selenide, or indium-gallium-copper selenide (CIS or CIGS), and more recently KESTERITAS.
    [0020] Both generations of solar cells, first and second, are based on semiconductors of a single spectral region ( pn junction), which, as mentioned, have their conversion energy limited by the Shockley and Quiesser limit. For the development of highly efficient solar cells, which can break the efficiency limit of single pn junction diodes, the third generation of solar cells, also known as highly efficient solar cells, has been created. This third generation includes multi-junction (tandem) solar cells, multi-band solar cells (MSC), up- and down-converters, and nanowire-based solar cells, among others. Multi-junction (tandem) cells are characterized by the use of various complementary semiconductor materials joined by a tunnel junction that allow photons of radiation from UV to near IR to be absorbed using each cell (or pn junction) for different regions of the spectrum. However, the The main disadvantage of this technology is the high cost associated with the complex manufacturing process generated by tunnel junctions, which are necessary to isolate some devices ( pn junctions) from others.
    [0022] In view of the limitations observed in the state of the art, it would be desirable to have semiconductor electronic devices with advantageous properties in various applications, such as those mentioned above.
    [0024] Brief description of the invention
    [0026] A different type of semiconductor device is proposed with multiple bipolar junctions, consisting of two or more diodes in phase opposition. An essential part of these structures is, at least, a layer formed by highly networked mismatched semiconductor alloys ( "Highly Mismatched Alloys" HMAs), such as dilute nitrides, for example. In these materials, a third band of intermediate energy other than the valence band and the conduction band that also allows the transport of charge carriers.
    [0028] In turn, another essential part for the operation of these devices requires the existence of one or more blocking layers that allow limiting the transport of the load carriers of the intermediate band formed by the HMAs to one side, or the other, or in both directions, that is to say limit the exchange of charge with the contacts of the semiconductor device.
    [0030] These new semiconductor devices have, at least, a double region of space charge, being formed by the different pn junctions of the device and / or by the blocking layers. The blocking layers are responsible for at least one of the space charge regions. This double region of space charge, together with the blocked intermediate band of the contacts, allows the operation of the semiconductor device regardless of the number of layers that form it.
    [0032] Although such a two-junction structure ( npn or pnp) may appear similar to a transistor, it is not an equivalent device. In fact, these devices, even being made up of more than two layers, do not need a contact in each of them, but allow the transport of charge with only two contacts in the first and last layer (an upper metallized region to a first contact and a lower metallized region for a second contact), which results in a significant simplification in your manufacturing process. However, by adding contact terminals to one or more of its intermediate layers, new control elements are obtained over the transport of cargo in the device as a whole.
    [0034] The transistor-like structure in terms of n and p layer stacking has demonstrated the generation of photovoltaic energy through the absorption of light, as well as the transport of charge in both forward and reverse polarization.
    [0036] In line with the above, one of the objects of the present invention refers to a new semiconductor electronic device of npn homo-junctions (with different polarity between the layers) or, alternatively, pnp (homo-junctions exist when the material is the same and change the doping). The device is made up of a succession of regions, one after the other, each with a specific conductivity. In the npn case:
    [0037] - There is a first region with an n- type doped first semiconductor (GaAsN) of a highly network mismatched alloy (HMA).
    [0038] - A second region follows with the first p- doped semiconductor (GaAsN) of a highly network mismatched alloy (HMA).
    [0039] - It continues with a third region with the first n- doped semiconductor (GaAsN) of a highly network mismatched alloy (HMA).
    [0040] - The previous regions are placed between two carrier blocking regions, an upper blocking region and a lower blocking region, both of a second n- type semiconductor (AlGaAs), which block the passage of carriers between the energy band E formed by the HMA and the contacts of the semiconductor device and that are responsible for a double region of space charge in the device for each np and pn junction.
    [0042] For the pnp case, the above sequence of regions with a given conductivity would be modified to the opposite conductivity type. That is, the areas doped with impurities n would become doped with p and vice versa (those of p would be n).
    [0044] Another object of the present invention refers to a new pnp hetero-junction semiconductor electronic device formed by a succession of regions, one after the other (hetero-junctions exist when, in addition to changing the doping, the materials change, that is, not all the materials used are the same).
    [0045] - There is a first region with a first semiconductor (AlGaAs) with p- type doping of a blocking layer.
    [0046] - A second region follows with a second semiconductor (GaAsN) with n- type doping of a highly network mismatched alloy (HMA).
    [0047] - It continues with a third region with the second semiconductor (GaAsN) with p- type doping of a highly network mismatched alloy (HMA).
    [0048] - The anterior region is covered with a last p-type first semiconductor (AlGaAs) blocking layer, which blocks the passage of carriers between the E- energy band formed by the HMA and the contacts of the semiconductor device. Like the first blocking layer, they are responsible for a double region of space charge in the device for each pn and np junction.
    [0050] Brief description of the figures
    [0052] For a better understanding of the invention, both with regard to its structure and its operation and its advantages, they are explained with the help of exemplary embodiments with reference to the attached drawings in which:
    [0054] FIG. 1 illustrates a diagram of the energy bands under equilibrium conditions for an example of a device with pnp homo-junctions according to the invention.
    [0056] FIG. 2A illustrates the layer structure of a diode of the state of the art. FIG.
    [0057] 2B illustrates the layer structure of a transistor of the state of the art. FIG. 2C illustrates an example of a device according to the invention for 3 layers and 2 joints. FIG.
    [0058] 2D illustrates an example of a device according to the invention for a greater number of layers and joints.
    [0060] FIG. 3 illustrates a schematic structure of the layers of an example of a device with pnp homo-junctions according to the invention, presenting the semiconductor layers HMA (GaAsN) placed between blocking layers (AlGaAs).
    [0062] FIG. 4 illustrates the band structure calculated from the model of the bands without crossing ( band anticrossing BAC) of a highly mismatched alloy (HMA) with dilute nitrides together with the possible optical transitions.
    [0064] FIG. 5 illustrates a band diagram under polarization conditions for an example of a device according to the invention.
    [0065] FIG. 6 illustrates the characteristic curve of current-voltage (I-V) experimental results under light and dark conditions for an example of a device according to the invention.
    [0067] FIG. 7A illustrates a possible structure of a device with pnp hetero-junctions according to the invention. FIG. 7B illustrates a possible structure of a device with npn homojunctions according to the invention.
    [0069] Detailed description of the invention
    [0071] With reference to the previous figures, various embodiments of the device object of the invention are described.
    [0073] In one embodiment of the device, it has a pnp or npn bipolar double junction structure, with a double region of space charge for each junction. However, in other embodiments of the device, it may have a greater number of layers p and n interspersed, forming a greater number of pn junctions.
    [0075] Highly network mismatched (HMA) semiconductor alloys are employed in the embodiments. HMAs are a class of materials created from very different semiconductors. Generally, they are formed by diluting nitrides (oxides) in which column V (VI) atoms in a standard group of compounds III-V (II-VI) are partially replaced with nitrogen (oxygen).
    [0077] One of the salient characteristics of these HMA materials is a massive modification of the energy band structure produced by small changes in the alloy composition. The structure of the band is well described by the model of bands without crossing ( “band anticrossing” or BAC) that is generated by the interaction between the level of the diluted element and the conduction band of the semiconductor that receives nitrogen (oxygen ) diluted. This model has shown that some of the dilute nitrides or oxides exhibit an unusual energy band structure containing a narrow band within the bandgap of the host material.
    [0079] FIG. 1 shows a band diagram of an example device according to one embodiment. Four regions of space charge are observed, two for each pn or np junction.
    [0080] This double region of space charge generated at each pn or np junction, together with the energy band generated from the HMAs, allows the transport of carriers in both forward and reverse polarization conditions, as well as producing photovoltaic energy generation by absorbing light. .
    [0082] FIGS. 2A and 2B respectively show the layer structure of a diode and a transistor according to the state of the art. FIG. 2C shows an example of a device according to the present invention for 3 layers and 2 joints. FIG. 2D shows an example of a device according to the present invention for a greater number of layers and junctions (x layers and x-1 junctions), with two regions of space charge.
    [0084] In FIG. 3 shows a simple schematic structure of the layers of the HMA semiconductor (GaAsN), a succession of highly mismatched regions in lattice 10, of an example of a semiconductor device 1 with pnp homo-junctions according to the invention, where the highly mismatched regions in lattice 10 they are positioned between two carrier blocking regions, lower blocking region 20 and upper blocking region 22, of a semiconductor (AlGaAs). The figure also shows a substrate 40 (or substrate region) on which a buffer region (50) is arranged, the metallized contacts of the semiconductor device (lower contact 30 and upper contact 32) and a protective region 60 located between the region upper blocker 22 and upper contact 32. All indicated regions, which are explained in detail in the embodiments of Figures 7A and 7B, can be layers or nanowires.
    [0086] In FIG. 4 shows the band structure (band of intermediate energy E- generated in the alloy, valence band VB and conduction band CB) of a GaAsN alloy calculated from the model of the bands without crossing (“band anticrossing”, BAC) also representing the possible optical transitions, A being the possible absorptions between the valence band VB and the energy band E-, B the transition between the energy band E- and the conduction band E + and C the possible transitions between the band of valence VB and the conduction band E +. The nitrogen level, which will limit the position of the energy band E-, is denoted by E n .
    [0088] In FIG. 5 shows how, under polarization conditions, the bands of the semiconductor device are modified showing the front region 2, formed by a first pn junction and two regions of space charge, under reverse polarization and the other rear region 3, formed by a second np junction and two regions of space charge, under forward polarization. The region that is in direct polarization allows the passage of current like any normal diode, while the region that is in reverse polarization also allows the passage of current, thanks to the tunnel current that occurs through the E- band in said double charging region space.
    [0090] When a forward bias voltage is applied (as shown in Figure 5), the potential drop is distributed between the front and back space charge regions. In the regions of frontal space charge the valence band (VB) moves upwards and injects electrons from the valence band (VB) to the E- band and the conduction band (E +). In the later regions of space charge, forward polarization shifts the conduction band (E +) of the substrate downward and injects gaps in the valence band (VB) and in the E- band. As a result, there is a reversal in the occupation with electrons in E + (CB), holes in the valence band (VB) and both carriers in the E- band.
    [0092] Thanks both to these double regions of space charge and to the blocking layers of carriers, the current can pass from one of the junctions to the other junction without the breaking phenomenon occurring and giving rise to a symmetrical behavior with respect to the passage of device current. This property of the passage of current through the two junctions with reversed polarity is what makes it possible to generate a device with a pnp (or npn) structure allowing the generation of photocurrent from the absorption of light as occurs in two junction devices. (solar cells), but having a higher number of layers and pn junctions.
    [0094] The first known material with a structure of three separate bands that allows photons from three different spectral regions to be absorbed and converted into electricity is GaAsN. However, it has been used in multiband diodes, that is, only in a pn junction.
    [0096] The highly network mismatched alloy (HMA), be it a tertiary or quaternary element (it is demonstrated with dilute nitrides in GaAs to form the tertiary GaAsN), must be placed between two p on-type doped blocking layers, depending on whether the structure is pnp or npn respectively. The blocking layers have been generated in such a way as to prohibit the passage of carriers between the intermediate energy band E- generated in the alloy and the contacts of the semiconductor device 1. The semiconductor material used for the blocking layers in the examples shown in the figures is AlGaAs, although others such as GaP or the GaAsIn. Both the pnp structure and the blocking layers do not need to be heavily doped. In the same way, the width of the different layers can vary.
    [0098] Depending on the concentrations of the diluted element, the energy bands E- and E + will separate more or less with respect to the valence band. In this way, the spectral region where the semiconductor device 1 is effective can be modulated.
    [0100] FIG. 6 shows the characteristic curves of experimental results of current-voltage (IV) under lighting conditions (curve 4) and under dark conditions (curve 5) for an example of a semiconductor device 1 according to the invention. This experimental result is the demonstration of photocurrent generation by light absorption for a 3 junction-4 layer npnp device.
    [0102] Details corresponding to different possible embodiments are explained with the aid of FIGS. 7A and 7B. For clarity, the simplest structure with 3 layers and 2 seams is chosen. However, it is expandable to a greater number of layers (e.g.
    [0103] 4 or more layers) and of joints (e.g. 3 or more joints).
    [0105] FIG. 7A exhibits a "hetero-linkage" of p-AlGaAs / n-GaAsN / p-GaAsN / p-AlGaAs ( pn-p). FIG. 7B exhibits a "homo-bonding" n-AlGaAs / n-GaAsN / p-GaAsN / n-GaAsN / n-AlGaAs (npn).
    [0107] With these two examples, it is wanted to prove that a device according to the present invention can be advantageously manufactured in various ways. One, using the same material for its layers simply by varying the doping. Another, using the same blocking layer to perform a hetero-union, where not only doping but also the material used is varied (and that allows reducing the number of total layers of the device).
    [0109] To illustrate the first case, that of a semiconductor device with p-np hetero-junctions, reference is made to FIG. 7A. A possible manufacturing method would be the following:
    [0110] - A buffer layer 50: By means of epitaxial growth of molecular beams (MBE) or chemical beams (CBE), a buffer layer 50 of p- type GaAs is grown on a substrate 40 of GaAs that allows to accommodate the growth with a thickness 0.04 mm. This buffer layer 50 also acts as a back surface field layer. ("Back surface field") in order to reduce the speed of subsequent surface recombination. Next, the rest of the structure of the device is grown starting with:
    [0111] - A lower blocking layer 20: The lower blocking layer 20 has a thickness of 0.05 mm of p-type AlGaAs, it is doped with carbon with an impurity concentration of 10 18 cm -3 . This lower blocking layer 20 hinders the flow of carriers between the E- band and the lower contact 30 of the device (lower metallized layer).
    [0112] - A first layer of a highly network mismatched alloy 12: This first layer 12 has a thickness of 0.5 mm of GaAsN, type n- doped with tin with an impurity concentration of 10 18 cm -3 . The diluted element in this case is nitrogen with a concentration of 3% to produce the effect "band anticrossing" (bands without crossing), appearing two bands formed and separated from each other above the valence band. In this way the first pn heterojunction of p- AlGaAs / n-GaAsN is formed.
    [0113] - A second layer of a highly network mismatched alloy 14: This second layer 14 has a thickness of 0.06 mm of GaAsN, p- doped with carbon with an impurity concentration of 10 18 cm -3 . The dilute nitrogen concentration is identical to the previous layer, being 3%. The difference between these two layers lies in the type of doping to be able to create a np homo-union.
    [0114] - An upper blocking layer 22: The upper blocking layer 22 grows on top of the pnp structure of the HMAs, being of the p- type of Al 0.45 Ga 0.55 As, doped with carbon with a concentration of 5x10 18 cm -3 and a thickness of 0 , 03 mm. This upper blocking layer 22 prevents the passage of carriers between the E- band and the upper contact 32 of the semiconductor device 1 (upper metallized layer) and also passivates the front emitter.
    [0115] - A protective layer 60: A 5 nm thick layer of p- type GaAs is grown with the same concentration as the upper blocking layer 22 in order to prevent oxidation of the upper blocking layer 22 of AlGaAs.
    [0116] - Metallized contacts: To finish the semiconductor device 1, by using conventional techniques of photolithography and a controlled chemical attack, the metallization of the upper contact 32 is carried out. Again, by using photolithographic techniques, the semiconductor devices are isolated from each other. by making tables. Finally, metal is deposited on the bottom (or back) of the semiconductor device to form the bottom contact 30. In the case of the bottom contact 30 a continuous metallic layer is deposited without the need to leave windows for the entry of light. In the case of the upper contact 32, a metallic discontinuous layer is deposited to leave windows 34 that allow light to enter.
    [0118] Similarly, referring to FIG. 7B, a possible method of manufacturing a semiconductor device with npn homo-junctions is explained:
    [0119] - A buffer layer 50: Through epitaxial growth, applying molecular beam epitaxy (MBE) or chemical beam (CBE) techniques, a buffer layer 50 of type n GaAs is grown on a substrate 40, a buffer layer 50 of type n GaAs that allows to accommodate growth with a thickness of 0.04 pm. The buffer layer 50 also acts as a back surface field layer in order to reduce the rate of back surface recombination. Next, the structure of the device is grown starting with:
    [0120] - A lower blocking layer 20: A layer of 0.05 pm thickness of AlGaAs type n, doped with tin, Sn, with an impurity concentration of 1018 cm-3. This layer is a carrier blocking layer ("blocking layer") between the E- band and the lower contact 30 of the semiconductor device.
    [0121] - A first layer of a highly misadjusted alloy in lattice 12: The layer is 0.06 µm thick of GaAsN, n- doped with tin, with an impurity concentration of 1018 cm-3. The diluted element used is nitrogen with a concentration of 3% to produce the "band anticrossing" effect, with two bands formed and separated from each other above the valence band.
    [0122] - A second layer of a highly misadjusted alloy in lattice 14: The layer is 0.5 pm thick of GaAsN, p- doped with carbon with an impurity concentration of 1018 cm-3. The dilute nitrogen concentration is identical to the first layer 12, the difference between these two layers is the type of doping to be able to create a first np homo-bond.
    [0123] - A third layer of a highly misaligned alloy in lattice 16: Again, a layer of 0.06 pm thick of GaAsN doped type n with tin is grown, with an impurity concentration of 1018 cm-3. The dilute nitrogen concentration is also the same as the two previous layers (12, 14), in this case again being type n in order to grow the second pn homo-bond and giving rise to the npn homo-structure.
    [0124] - An upper blocking layer 22: The new carrier blocking layer grows on top of the npn structure of the HMAs, being of the n- type of Al 0 . 45 Ga 0 . 55 As, doped with tin, with a concentration of 1018 cm-3 and a thickness of 0.03 pm. This Blocking layer prevents the passage of carriers between the E- band and the upper contact 32 of the semiconductor device 1, in addition to passivating the front emitter.
    [0125] - A protective layer 60: A 5 nm thick layer of n- type GaAs is grown with the same concentration as the previous layer in order to avoid oxidation of the upper blocking layer 22 of AlGaAs.
    [0126] - Metallized contacts: To finish the semiconductor device 1, by using conventional techniques of photolithography and a controlled chemical attack, the metallization of the upper contact 32 is carried out. Again by using photolithographic techniques, the semiconductor devices are isolated from each other by making tables. Finally, metal is deposited on the bottom (or rear) part of the semiconductor device to form the bottom contact 30. In the case of the bottom contact 30, a continuous metallic layer is deposited without the need to leave windows for the entry of light. In the case of the upper contact 32, a metallic discontinuous layer is deposited to leave windows 34 that allow light to enter.
    [0128] The new device has multiple applications: it is capable of detecting radiation, emitting radiation in different spectral regions, and it can also be used as a multi-junction solar cell without the need to have tunnel junctions between the different cells that make up the multi-junction solar cell. Generating in this way a great advance in the technology of multi-junction solar cells, by eliminating the most complex technological element in this type of solar cells. Furthermore, as shown in FIG. 6, the new semiconductor device 1 has a photovoltaic effect and can be used as a "multi-structure" solar cell. In this sense, when a photon is absorbed, it causes an electronic transition from the valence band to the E- and E + bands, as well as from the E- band to the E + band. These generated electron-hole pairs are extracted from the device in photocurrent mode. Additionally, by adding contact terminals to one or more of its intermediate layers, new control elements are obtained over the transport of cargo in the device as a whole.
    [0130] The semiconductor device 1 according to the invention (independent of the number of layers) can also be used as a photodetector in current or voltage mode.
    [0132] Adding more additional semiconductor layers allows you to dedicate certain layers to reduce the speed of surface recombination or, if they are highly doped, can improve the quality of the metallic contacts.
    [0133] Finally, it should be mentioned that it is not essential for the operation of the semiconductor device 1 that the structures have the form of layers. On the contrary, other types of structures can be used, such as nanowires, both columnar and core-shell. It is only necessary that there is a region with one type of conductivity, then another with the opposite, followed again by another region with the first type of conductivity (this sequence of consecutive regions can be expanded further). Thus a region p, another n and again another p of semiconductor material is presented, or alternatively a region n, another p and again another n of semiconductor material. It is also necessary that said regions have a highly misaligned material in the network (HMA) and that they are placed between blocking regions of carriers with p-doping, in case the structure is pnp or type n in case the structure is npn.
    [0135] The electronic device described can be used in different industrial applications such as photodetector, multi-color emitter and solar cell. The 4-layer, 3-junction device can be used as a thyristor without the need to generate a trigger contact, allowing it to switch between its conduction states by the action of light. As well as the 3 layer 2 junction device it can be used as a transistor with photovoltaic effect.
    [0137] As a photodetector it can be used to detect infrared radiation, both in the high wavelength infrared region (1-30mm) and in the far infrared region (more than 30mm) depending on the concentration of diluted nitrogen in the semiconductor host. This ability to detect infrared light makes them useful in manufacturing gas and molecule analyzers, flame detectors, and thermal cameras.
    [0139] It can emit in three different wavelengths depending on the concentration of dilute nitrogen introduced into the host semiconductor. It can be industrialized as an emitter with multiple wavelengths, expanding the number of wavelengths at which it is capable of acting if a different nitrogen concentration occurs between the two pn junctions that make up the semiconductor device 1. In this sense, the Semiconductor device 1 according to the invention can be forward or reverse polarized by emitting at least three different wavelengths that can range from visible light to infrared light.
    [0140] For the photovoltaic field, its application is directly related to the way it works, as well as to multi-junction solar cells or (tandems). The device has demonstrated its photovoltaic response, generating photocurrent by absorbing light. With respect to tandem cells, these cells are currently made up of different semiconductors ( pn junctions disconnected from each other, forming a strongly doped tunnel junction). Thus they achieve the isolation between the different cells that make up the photovoltaic device. On the other hand, the semiconductor devices 1 proposed in the present invention allow the formation of multi-junction cells, without the need for them to be disconnected by forming a tunnel junction between them. This fact significantly simplifies their manufacture. Another industrial advantage is linked to lower costs. Device manufacturing complexity is reduced by allowing multiple absorption regions and decreasing the number of junctions and layers that are necessary to grow in current tandem cells.
    权利要求:
    Claims (19)
    [1]
    1. Semiconductor device, comprising a substrate (40) and metallized contacts (30, 32), characterized in that the semiconductor device (1) additionally comprises:
    a succession of regions (10) formed by highly network mismatched semiconductor alloys, arranged one after another and with opposite doping types between adjacent regions of said succession of regions (10); and carrier blocking regions (20, 22) with the same type of doping and located at both ends of the succession of regions (10).
    [2]
    2. Semiconductor device according to claim 1, characterized in that the succession of regions (10) comprises:
    a first region (12) with a first semiconductor of a highly network mismatched alloy with doping of a first type;
    a second region (14) with a second semiconductor of a highly networked mismatched alloy with doping of a second type as opposed to the first type.
    [3]
    Semiconductor device according to claim 2, characterized in that the succession of regions (10) comprises:
    a third region (16) with a third semiconductor of a highly network mismatched alloy with a doping like the first type.
    [4]
    Semiconductor device according to claim 3, characterized in that the succession of regions (10) comprises one or more additional regions, with opposite doping between adjacent regions, and where each additional region is formed by a semiconductor of a highly network mismatched alloy. .
    [5]
    Semiconductor device according to any of the preceding claims 2 to 4, characterized in that the doping of the first type is n and the doping of the second type is p.
    [6]
    Semiconductor device according to any of the preceding claims 2 to 4, characterized in that the doping of the first type is p and the doping of the second type is n.
    [7]
    Semiconductor device according to any of the preceding claims, characterized in that the carrier blocking regions comprise an upper blocking region (22) and a lower blocking region (20) that enclose the succession of regions (10), where both blocking regions (20, 22) are of a fourth semiconductor.
    [8]
    Semiconductor device according to claim 7, characterized in that the semiconductor of the blocking regions (20, 22) belongs to the groups III-V or II-VI with a higher energy band gap than the highly misadjusted semiconductors in the network. succession of regions (10).
    [9]
    9. Semiconductor device according to claim 8, characterized in that the semiconductor of the blocking regions (20, 22) is any of the following: AlGaAs, GaP, GaAsIn, InGaP, ZnO, ZnTe, ZnSe.
    [10]
    Semiconductor device according to any of the preceding claims, characterized in that the highly network mismatched semiconductor alloys that form each region (12, 14, 16) of the succession of regions (10) are selected from the following: GaAsN, GaAsNP, GaInNAs, ZnOTe, ZnOSe, ZnSTe, ZnSeTe.
    [11]
    Semiconductor device according to any of the preceding claims, characterized in that it comprises a buffer region (50), located between the substrate (40) and one of the carrier blocking regions, and configured to act as a posterior surface field layer with effect to reduce the rate of subsequent surface recombination.
    [12]
    Semiconductor device according to claim 11, characterized in that the buffer region (50) is formed by a semiconductor with the same type of doping as the substrate (40) and the adjacent carrier blocking region, where the semiconductor is selected from among the following: GaAs, GaP, ZnO.
    [13]
    Semiconductor device according to any of the preceding claims, characterized in that it is comprised of metallized contacts: an upper contact (32) formed by a discontinuous metallic layer that allows light to pass through and a lower contact (30).
    [14]
    Semiconductor device according to claim 13, characterized in that it comprises a protective region (60) arranged between the upper contact (32) and one of the carrier blocking regions (22) in order to prevent oxidation of said carrier blocking region carriers.
    [15]
    Semiconductor device according to claim 14, characterized in that the protective region (60) is formed by GaAs and the adjacent carrier blocking region (22) is formed by AlGaAs.
    [16]
    16. Semiconductor device according to any of the preceding claims, characterized in that the substrate (40) is formed by a semiconductor selected from the following: GaAs, GaP, ZnO.
    [17]
    17. Semiconductor device according to any of the preceding claims, characterized in that the regions of the semiconductor device (1) are layers.
    [18]
    18. Semiconductor device according to any of the preceding claims, characterized in that the regions of the semiconductor device (1) are nanowires.
    [19]
    19. Semiconductor device according to any of the preceding claims, characterized in that it comprises at least one contact terminal in at least one intermediate layer to control charge transport in the device assembly.
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    同族专利:
    公开号 | 公开日
    WO2021044072A1|2021-03-11|
    ES2810599B2|2021-12-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO2000077829A2|1999-06-09|2000-12-21|Universidad Politecnica De Madrid|Intermediate band semiconductor photovoltaic solar cell|
    US20100180936A1|2009-01-19|2010-07-22|Samsung Electronics Co., Ltd.|Multijunction solar cell|
    US20170062651A1|2015-08-28|2017-03-02|The Regents Of The University Of California|Multicolor Electroluminescence from Intermediate Band Semiconductor Structures|
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