Distance sensor and distance image sensor.

专利摘要:
A distance sensor includes: a light receiving area having a first side edge and a second side edge; a photo gate electrode disposed on the light receiving area; a plurality of signal charge collection regions on the first side edge side; a plurality of signal charge collection regions on the second side edge side; a plurality of first side edge side transfer electrodes provided with charge transfer signals having phases different from each other; a plurality of transfer electrodes on the second side edge side, which can be charged with the charge transfer signals having phases different from each other; and a potential adjusting device positioned between the first side edge and the second side edge and adapted to raise the potential of the light receiving area extending toward the first and second side edges to be higher than a potential of an area adjacent to first side edge, and an area disposed adjacent to the second side edge, so that an inclination of the potential is formed from the area to the side of the first side edge and the side of the second side edge.
公开号:CH709088B1
申请号:CH00600/15
申请日:2013-07-05
公开日:2017-10-13
发明作者:Mase Mitsuhito；Hiramitsu Jun；Suzuki Takashi
申请人:Hamamatsu Photonics Kk；
IPC主号:

专利说明:

Description TECHNICAL FIELD The present invention relates to a distance sensor and a distance image sensor.
Background Art TOF (time-off flight) type diatancy image sensors (distance sensors) are known. For example, Patent Literature 1 and 2 disclose technologies for improving the transfer speed of distance image sensors. In the sensors described in Patent Literature 1 and 2, a pair of transfer electrodes used for transferring an electric charge generated in an electric charge generating region to an electric charge collecting region along a predetermined one side of the FIG Electric charge generating region arranged with a rectangular shape. In the electric charge generation region, the impurity concentration increases to the predetermined one side, and a slope in the potential distribution is formed to the predetermined one side. Accordingly, the electric charge generated in the electric charge generating region can easily move to the transmitting electrodes.
For example, in Patent Literature 3 for a distance image sensor, technology for suppressing crosstalk between transfer electrodes to which signals of mutually different phases are input is disclosed. In a sensor disclosed in Patent Literature 3, the transfer electrodes to which signals of phases different from each other are input are arranged to oppose each other across an electric charge generating region. In the electric charge generation region, an impurity region which is an isolation region is disposed between the transfer electrodes. Accordingly, only an electric charge generated in a portion located on one side of the impurity region in the electric charge generation region moves to the transfer electrode on one side and only an electric charge generated in one portion is located on the other side of the impurity region in the electric charge generation region, moves to the transfer electrode of the other side.
CITATION
Patent Literature [0004]
Patent Literature 1: Publication of Japanese Patent Application Laid-Open No. 2010-40594
Patent Literature 2: Publication of U.S. Patent Application No. 2011/01998481
Patent Literature 3: Publication of US Patent Application No. 2011/0188,026
SUMMARY OF THE INVENTION Technical Problem It is an object of the present invention to provide a distance sensor and a distance image sensor capable of achieving an improvement in the transfer speed, an improvement in transfer accuracy, and an improvement in an aperture ratio. Solution to Problem [0006] According to one aspect of the present invention, there is provided a distance sensor according to claims 1 to 9.
According to another aspect of the present invention, there is provided a distance image sensor having an image sensing area configured by a plurality of units arranged in a one-dimensional pattern or a two-dimensional pattern on a semiconductor substrate, and a distance image based on sets electric charges acquired by the units, each of the units being the distance sensor according to one of the distance sensors described above.
According to the present invention, as described above, an improvement in the transfer speed, an improvement in transfer accuracy, and an improvement in the aperture ratio can be achieved.
Advantageous Effects of Invention According to the present invention, it is possible to provide a diatonic sensor and a distance image sensor capable of achieving an improvement in transfer speed, an improvement in transfer accuracy, and an improvement in an aperture ratio.
Brief description of the drawings [0010]
FIG. 1 is a configuration diagram of a distance measuring device according to an embodiment. FIG.
FIG. 2 is a cross-sectional view of a distance image sensor according to an embodiment. FIG.
FIG. 3 is a plan view of the distance image sensor illustrated in FIG. 2. FIG.
FIG. 4 is a plan view illustrating a part of a distance sensor illustrated in FIG. 3. FIG.
Fig. 5 is a cross-sectional view taken along a line V-V illustrated in Fig. 4;
Fig. 6 is a cross-sectional view taken along a line Vl-Vl illustrated in Fig. 4;
Fig. 7 is a cross-sectional view taken along a line VII-VII illustrated in Fig. 4;
Fig. 8 is a diagram illustrating a potential distribution for describing an operation for accumulating an electric charge.
9 is a diagram illustrating a potential distribution for describing an operation for accumulating an electric charge, as shown in FIG. 8.
10 is a diagram illustrating a potential distribution for describing an operation for discharging an electric charge.
Fig. 11 is a timing chart of various signals.
Fig. 12 is a plan view illustrating a part of a distance sensor according to another embodiment.
Fig. 13 is a plan view illustrating a part of a distance sensor according to still another embodiment.
Fig. 14 is a plan view illustrating a part of a distance sensor according to still another embodiment.
Fig. 15 is a plan view illustrating a part of a distance sensor according to still another embodiment.
16 is a plan view illustrating a part of a distance sensor according to still another embodiment.
Fig. 17 is a plan view illustrating a part of a distance sensor according to still another embodiment.
Fig. 18 is a plan view illustrating a part of a distance sensor according to still another embodiment.
Fig. 19 is a plan view illustrating a part of a distance sensor according to still another embodiment.
Fig. 20 is a diagram illustrating a potential distribution on a cross section taken along a line XX-XX illustrated in Fig. 19.
Fig. 21 is a plan view illustrating a part of a distance sensor according to still another embodiment.
Fig. 22 is a cross-sectional view taken along a line XXII-XXII illustrated in Fig. 21;
Fig. 23 is a plan view illustrating a part of a distance sensor according to still another embodiment.
Fig. 24 is a cross-sectional view taken along a line XXIV-XXIV illustrated in Fig. 23; DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numeral becomes the same
Elements or elements with the same function will be used, and a duplicate description of them will not be presented.
Fig. 1 is a configuration diagram of a distance measuring device according to an embodiment.
This distance measuring device includes: a distance image sensor 1; a light source 3 that emits near-infrared light; a drive circuit 4; a control circuit 2; and a working circuit 5. The drive circuit 4 supplies a pulse drive signal SP to the light source 3. The control circuit 2 supplies a detection gate signal S-1 synchronized with the pulse drive signal SP to first gate electrodes TXI-i and TX12 (see FIG ) included in each distance sensor P1 (see Fig. 3) of the distance image sensor 1 as a charge transfer signal, supplies a detection gate signal S2 having a phase different from the pulse drive signal SP and a detection Ga signal Si second gate electrodes TX2- |. and TX22 (see Fig. 4) as a charge transfer signal, and supplies a discharge gate signal S3 to third gate electrodes TX3i and TX32 (see Fig. 4) as a charge transfer signal. The working circuit 5 calculates a distance to a target object H such as a pedestrian based on signals d-1 and d2 from first semiconductor regions FD 13 and FD12 (see FIG. 4) and second semiconductor regions FD2- | and FD22 (see Fig. 4) of each distance sensor P1 are read and represent distance information. It is assumed that a distance from the distance image sensor 1 to the target object H in the horizontal direction D is "d".
The control circuit 2 inputs the pulse drive signal SP to a switch 4b of the drive circuit 4. The light source 3, which is configured by LEDs or laser diodes and used for illuminating, is connected to a power source 4a through the switch 4b. When the pulse drive signal SP is input to the switch 4b, a drive current having the same waveform as the pulse drive signal SP is supplied to the light source 3, and an emission pulse light LP as a probe light used to measure a distance is output from the light source 3. When the emission pulse light LP is emitted to the target object H, the pulse light is reflected by the target object H. The reflected pulse light impinges on the distance image sensor 1 as detection pulse light LD. While the detection pulse light LD is incident on the distance image sensor 1, a pulse detection signal SD is output from the distance image sensor 1.
The distance image sensor 1 is arranged on a wiring substrate 10. The signals di and d2 each having distance information are output from each distance sensor P1 of the distance image sensor 1 by wirings formed on the wiring substrate 10.
Fig. 2 is a cross-sectional view of the distance image sensor according to the embodiment.
The distance image sensor 1 is a front-illuminated type distance image sensor and includes a semiconductor substrate IA. The semiconductor substrate 1A is formed by using Si or the like. The detection pulse light LD is incident on the distance image sensor 1 from a light entrance surface 1FT of the semiconductor substrate 1A. A back surface 1BK of the distance image sensor 1, which is opposite to the light entrance surface 1FT, is connected to the wiring substrate 10 through an adhesion region AD. The adhesion region AD contains insulating adhesives, fillers and the like. The distance image sensor 1 includes a light shielding layer LI in which an opening Lla (see FIGS. 5 to 7) is formed at a predetermined position. The light shielding layer LI is disposed on the front side of the light entrance surface 1FT. The light-shielding layer LI is formed, for example, by using metal such as aluminum.
FIG. 3 is a plan view of the distance image sensor illustrated in FIG. 2. FIG.
In the distance image sensor, the semiconductor substrate 1A has an imaging region 1B configured by a plurality of (here three) distance sensors (units) P1 arranged in a one-dimensional pattern along the X direction. Image region 1B shows a rectangular shape (more precisely, a square shape). The distance sensor P1 shows a rectangular shape with the Y-direction being perpendicular to the X-direction as its longitudinal direction in the plan view. For example, in the distance sensor P1, a ratio of a shorter side to a longer side is about 1/3. An electric charge amount Q1 and an electric charge amount Q2 are output from the distance sensor P1 as the signals d-1 and d2 with distance information as described above. Between the distance sensors P1 and P1 which are adjacent to each other, a wiring used for outputting the electric charge amount Q1 is shared, and a wiring used for outputting the electric charge amount Q2 is shared. The distance sensor P1 is a micro-area sensor, and outputs the electric charge amount Q1 and the electric charge amount Q2 according to a distance to the target object H. Thus, by forming an image of the reflected light reflected from the target object H in the imaging region IB, a distance image of the target object can be acquired as an aggregation of distance information to each point on the target object H. The distance sensor P1 serves as a pixel.
FIG. 4 is a plan view illustrating a part of the distance sensor illustrated in FIG. 3. FIG. Fig. 5 is a cross-sectional view taken along a line V-V illustrated in Fig. 4; Fig. 6 is a cross-sectional view taken along a line Vl-Vl illustrated in Fig. 4; Fig. 7 is a cross-sectional view taken along a line VII-VII illustrated in Fig. 4; In Fig. 4, the light-shielding layer LI is not illustrated (the same applies to Figs. 12 to 19, Fig. 21 and Fig. 23).
The distance image sensor 1 as described above includes the semiconductor substrate 1A including the light entrance surface 1FT and the back surface 1BK facing each other (see FIG. 2). The semiconductor substrate 1A has a first p-type substrate region 1Aa positioned on the back surface 1BK side and a second p "-type substrate region 1Ab positioned on the light-incident surface 1FT side. The impurity concentration of the second substrate region 1Ab is lower than that of the first substrate region 1Aa. For example, the semiconductor substrate 1A may be acquired by growth on a p-type semiconductor substrate, a p "-type epitaxial layer having an impurity concentration lower than the semiconductor substrate.
The distance sensor P1 includes: a photo gate electrode PG1; a plurality of first semiconductor regions FDI-i and FD12; a plurality of second semiconductor regions FD2-I and FD22; a plurality of third semiconductor regions FD3i and FD32; a fourth semiconductor region SR1; fifth semiconductor regions SR2-I and SR22; a plurality of first gate electrodes TX1 -i and TX12; a plurality of second gate electrodes TX2-I and TX22; and a plurality of third gate electrodes TX3i and TX32.
The photo gate electrode PG1 is disposed on the light incident surface 1FT through an insulating layer 1E formed using SiO 2 or the like. The photo gate electrode PG1 is arranged in association with the opening Lla formed in the light shielding layer LI. The shape of the opening Lla shows a rectangular shape with the Y direction as its longitudinal direction in the plan view. The photo-gate electrode PG1 shows a shape corresponding to the opening Lla, and shows a rectangular shape with the Y direction as its longitudinal direction in plan view. The photo-gate electrode PG1 is formed using polysilicon, but may be formed using any other material.
Light (reflected light from the target object H) is incident on the semiconductor substrate 1A through the opening Lla. A light receiving area is defined in the semiconductor substrate 1A through the opening Lla. The light receiving area corresponds to the shape of the opening Lla and shows a rectangular shape with the Y direction as its longitudinal direction. The light receiving area includes: first and second longer sides LS1 and LS2 facing each other in the X direction, extending in the Y direction; and first and second shorter sides SSI and SS2 facing each other in the Y direction extending in the K direction (see Fig. 3). The length of each of the first and second longer sides LS1 and LS2 is longer than a space between the first and second longer sides LS1 and LS2.
In the light receiving area, an area corresponding to the photo gate electrode PG1 (an area just below the photo gate electrode PG1) serves as an electric charge generating region in which an electric charge according to the incident light is produced. In this embodiment, the shape of the light receiving area, the shape of the photo gate electrode PG1, and the shape of the electric charge generating region coincide with each other in plan view. In each plan view, for description, each side of the light receiving area and each side of the photo-gate electrodes PG1 are shown to be shifted.
In the light receiving area, an area including the first longer side LS1 and extending in a direction in which the first longer side LS1 extends is a first area. Moreover, in the light receiving area, an area including the second longer side LS2 and extending in a direction in which the second longer side LS2 extends is a second area. Between the first region and the second region, the fourth semiconductor region SR1 is arranged.
A region (the first to third semiconductor regions FD1i to FD32, the fifth semiconductor region SR2, and an area having regions in which the first to third gate electrodes TXI-i to TX32 are arranged) of the semiconductor substrate 1A are different from the light receiving region is covered with the light shielding layer LI, and light is prevented from being incident on such a region. Accordingly, generation of unnecessary electric charge caused by light incident on the area can be prevented.
In a region of the first longer side LS1 side separated from the light receiving region in the X direction, a plurality of first semiconductor regions FDI-i are arranged to be separated from each other along the first longer side LS1. In a region of the second longer side LS2 side separated from the light receiving region in the X direction, a plurality of first semiconductor regions FD12 are arranged to be separated from each other along the second longer side LS2 and connected to the respective first semiconductor regions FDI12, respectively. i, which are located on the side of the first longer side LS1, over the light receiving area. In this embodiment, the first semiconductor region FD1-i disposed on the side of the first longer side LS1 and the first semiconductor region FD12; which is arranged on the side of the second longer side LS2, facing each other in the X direction.
In the area of the first longer side LS1 side separated from the light receiving area in the X direction, a plurality of second semiconductor regions FD2-I are arranged to be separated from each other along the first longer side LS1. In the area of the side of the second longer side LS2 separated from the light receiving area in the X direction, a plurality of second semiconductor regions FD22 are arranged to be separated from each other along the second longer side LS2 and to surround the corresponding second semiconductor regions FD2- I, which are located on the side of the first longer side LS1, above the light receiving area. The first semiconductor region FDI-i and the second semiconductor region FD2 · are alternately arranged in the Y direction so as to be separated from each other. The first semiconductor region FD12 and the second semiconductor region FD22 are alternately arranged in the Y direction so as to be separated from each other. In this embodiment, the second semiconductor region FD2-I disposed on the first longer side LS1 side and the second semiconductor region FD22 located on the second longer side LS2 side face each other in the X direction.
The first and second gate electrodes ΤΧΉ and TX22 are disposed on the light incident surface 1FT through the insulating layer 1E. A plurality of first gate electrodes TXI-i are arranged to be separated from each other along the first longer side LS1 on the first longer side LS1 side, and the first gate electrode TX1 · i is interposed between the corresponding first semiconductor region FDI-i and the photo gate electrode PG1. A plurality of first gate electrodes TX12 are arranged to be separated from each other along the second longer side LS2 on the side of the second longer side LS2, and the first gate electrode TX12 is interposed between the corresponding first semiconductor region FD12 and the photo gate. Electrode PG1 arranged. The first gate electrodes TX1i disposed on the first longer side LS1 side and the first gate electrodes TX12 located on the second longer side LS2 side face each other in the X direction.
[0031] A plurality of second gate electrodes TX21 are arranged to be separated from each other along the first longer side LS1 on the first longer side LS1 side, and the second gate electrode TX2-I is interposed between the corresponding second semiconductor region FD2- I and the photo gate electrode PG1. A plurality of second gate electrodes TX22 are arranged to be separated from each other along the second longer side LS2 on the side of the second longer side LS2, and the second gate electrode TX22 is interposed between the corresponding second semiconductor region FD22 and the photo gate. Electrode PG1 arranged. The first gate electrode TXI-i and the second gate electrode TX2-I are alternately arranged in the Y direction and are separated from each other. The first gate electrode TX12 and the second gate electrode TX22 are alternately arranged in the Y direction and are separated from each other. The second gate electrodes TX2-I disposed on the first longer side LS1 side and the second gate electrodes TX22 located on the second longer side LS2 side face each other in the X direction.
The first and second semiconductor regions FDI-i to FD22 show a polygon shape in plan view. In this embodiment, the first and second semiconductor regions to FD22 show a rectangular shape (more precisely, a square shape). However, the shape of the first and second semiconductor regions FDI-i to FD22 is not limited to a polygon. The first and second semiconductor regions FDI-i to FD22 accumulate an electric charge flowing into regions just below the respective first and second gate electrodes TXI-i to TX22. The first and second semiconductor regions FD1 | and FD21 disposed on the first longer side LS1 side serve as a first side signal charge collection region. The first and second semiconductor regions FD12 and FD22 disposed on the second longer side LS2 side serve as a second-side signal charge collection region. The first and second semiconductor regions FD1 * to FD22 are regions formed by an n-type semiconductor having a high impurity concentration, and are floating diffusion regions.
Each of the first and second gate electrodes TX1i to TX22 shows a polygon shape in plan view. In this embodiment, each of the first and second gate electrodes TXI-i to TX22 exhibits an approximate rectangular shape (more specifically, a rectangular shape with the Y direction as its longer-side direction). However, the shapes of the first and second gate electrodes TX11 to TX22 are not limited to one polygon. The first gate electrodes TXI-i and TX12 selectively perform blocking and enabling the flow of a signal charge to the first semiconductor regions FDI-i and FD12, respectively, based on a given corresponding detection gate signal S-ι. The second gate electrodes TX2-I and TX22 selectively perform blocking and enabling the flow of a signal charge to the second semiconductor regions FD2-I and FD22, respectively, based on a given corresponding detection gate signal S2. The first and second gate electrodes TX1 *, and TX2 * arranged on the side of the first longer side LS1 serve as first-side transfer electrodes. The first and second gate electrodes TX12 and TX22 disposed on the side of the second longer side LS2 serve as second-side transfer electrodes. The first and second gate electrodes TXI-i through TX22 may be formed using polysilicon or any other material.
In the region of the first longer side LS1 side separated from the light receiving region in the X direction, a plurality of third semiconductor regions FD3i are arranged to be separated from each other along the first longer side LS1. In the region of the second longer side LS2 side separated from the light receiving region in the X direction, a plurality of third semiconductor regions FD32 are arranged to be separated from each other along the second longer side LS2 and to the respective third semiconductor regions FD3 -I, which are arranged on the side of the first longer side LS1, over the light receiving area. The third semiconductor region FD3-I is arranged to be separated from the first and second semiconductor regions FDI-1 and FD2-I in the Y-direction, and the third semiconductor region FD32 is arranged to be separated from the first and second semiconductor regions FD12 and FD22 to be separated in the Y direction. In this embodiment, the third semiconductor regions FD3-I are disposed between all of the first and second semiconductor regions FD12 and FD2-I in the Y direction, and the third semiconductor regions FD32 are between all of the first and second semiconductor regions FD12 and FD22 in the Y direction arranged. Moreover, the third semiconductor regions FD3-I may also be arranged at both ends in the Y direction to have all of the first and second semiconductor regions FDI-1 and FD2-I interposed therebetween in the Y direction, and the third semiconductor regions FD32 may also be disposed at both ends in the Y direction to have all of the first and second semiconductor regions FD12 and FD22 interposed therebetween in the Y direction. The third semiconductor regions FD3i disposed on the first longer side LS1 side and the third semiconductor regions FD32 disposed on the second longer side LS2 side face each other in the X direction.
The third gate electrodes TX3- | and TX32 are disposed on the light entrance surface 1FT through the insulating layer 1E. A plurality of third gate electrodes TX3i are arranged to be separated from each other along the first longer side LS1 on the side of the first longer side LS1, and the third gate electrode TX3i is interposed between the corresponding third semiconductor region FD3-I and the photo-semiconductor device. Gate electrode PG1 arranged. A plurality of third gate electrodes TX32 are arranged to be separated from each other along the second longer side LS2 on the side of the second longer side LS2, and the third gate electrode TX32 is interposed between the corresponding third semiconductor region FD32 and the photo gate Electrode PG1 arranged. The third gate electrode TX32 is arranged to be separated from the first and second gate electrodes TXI-i and TX2-I in the Y direction, and the third gate electrode TX32 is arranged to be from the first and second ones Gate electrodes TX12 and TX22 to be separated in the Y direction. The third gate electrodes TX3i disposed on the first longer side LS1 side and the third gate electrodes TX32 located on the second longer side LS2 side face each other in the X direction.
The third semiconductor regions FD3-I and FD32 show a polygon shape in plan view. In this embodiment, the third semiconductor regions FD3i and FD32 show a rectangular shape (more precisely, a square shape). However, the shapes of the third semiconductor regions FD3-I and FD32 are not limited to one polygon. The third semiconductor regions FD3i and FD32 discharge an electrical charge that flows into areas just below the corresponding third gate electrodes TX3-I and TX32. The third semiconductor regions FD3-I and FD32 serve as a redundant electric charge discharge region (redundant electric charge-discharge drain) and are connected, for example, with a fixed electric potential. The third semiconductor region FD3-I, which is disposed on the first longer side LS1 side, serves as a first-side unnecessary electric charge discharge region. The third semiconductor region FD32 disposed on the side of the second longer side LS2 serves as a second-side-unnecessary-electric-charge-discharging region. The third semiconductor regions FD3i and FD32 are regions formed by an n-type semiconductor having high impurity concentration, and are floating diffusion regions.
Each of the third gate electrodes TX3i and TX32 shows a polygon shape in plan view. In this embodiment, each of the third gate electrodes TX3i and TX32 shows a rectangular shape (more specifically, a rectangular shape with the Y direction as its longer-side direction). However, the shapes of the third gate electrodes TX3i and TX32 are not limited to one polygon.
The third gate electrodes TX3i and TX32 selectively perform blocking and enabling the flow of excess electric charge to the third semiconductor regions FD3i and FD32, respectively, based on a given corresponding discharge gate signal S3. The third gate electrodes TX3i disposed on the side of the first longer side LS1 serve as first-side redundant-electric-charge-discharge gate electrodes. The third gate electrodes TX32 disposed on the side of the second longer side LS2 serve as second-side over-liquid-electric-charge-discharge gate electrodes. The third gate electrodes TX3-I and TX32 may be formed using polysilicon or any other material.
The fourth semiconductor region SR1 is disposed between the first and second longer sides LS1 and LS2 in a region just below the photo-gate electrode PG1. The fourth semiconductor region SR1 shows a rectangular shape with the Y direction as its longer-side direction in the plan view. The fourth semiconductor region SR1 extends in the Y direction to combine the first shorter side SSI and the second shorter side SS2 at a center portion between the first longer side LS1 and the second longer side LS2.
The fourth semiconductor region SR1 has the same conductivity type as that of the semiconductor substrate 1A, and is a region having an impurity concentration higher than that of the second substrate region 1Ab, in other words, is formed by a p-type semiconductor having a high impurity concentration. The fourth semiconductor region SR1 may be a p-type well region, a p-type well region, or a p-type diffusion region.
The fifth semiconductor region SR2- is arranged to extend along the first longer side LS1 in a region disposed on the side of the first longer side LS1 that is separate from the light-receiving region in the X-direction region. Direction. The fifth semiconductor region SR22 is arranged to extend along the second longer side LS2 in a region disposed on the side of the second longer side LS2 which is separated from the light receiving region in the X direction. Each of the fifth semiconductor regions SR2-I and SR22 has a rectangular shape with the Y direction as its longer-side direction in the plan view. The fifth semiconductor region SR2 ··· is disposed along the longer side of the distance sensor P1 on the first longer side LS1 side, and has a portion overlapping with the first to third semiconductor regions FDI-i to FD3-I disposed on the side of the first side longer side LS1 in plan view. The fifth semiconductor region SR22 is disposed along the longer side of the distance sensor P1 on the second longer side LS2 side, and has a portion overlapping the first to third semiconductor regions FD12 to FD32 disposed on the second longer side LS2 side in the plan view.
The fifth semiconductor regions SR2-I and SR22 have the same conductivity type as that of the semiconductor substrate 1A and are regions having impurity concentrations higher than that of the second semiconductor region 1Ab, in other words, are formed by a p-type semiconductor having a high impurity concentration. The fifth semiconductor regions SR2-I and SR22 may be p-type well regions, p-type well regions, or p-type diffusion regions, respectively. However, the fifth semiconductor regions SR2-I and SR22 need not be arranged.
The thickness / impurity concentration of each region are as follows.
[0044] First Substrate Region 1Aa of Semiconductor Substrate 1A:
Thickness of 5 to 700 pm / impurity concentration of 1 x 1018 to 1020 cm-3 Second substrate region 1Ab of semiconductor substrate 1A:
Thickness of 3 to 50 μm / impurity concentration of 1 × 10 13 to 10 16 cm -3. [0046] First semiconductor regions FDI-1 and FD12:
Thickness of 0.1 to 0.4 pm / impurity concentration of 1 x 1018 to 102 [deg.] Cm-3 Second semiconductor regions FD2-I and FD22:
Thickness from 0.1 to 0.4 pm / impurity concentration of 1 × 10 18 to 102 ° cm-3 Third semiconductor regions FD3-I and FD32:
Thickness of 0.1 to 0.4 pm / impurity concentration of 1 x 1018 to 102 ° cm-3 Fourth semiconductor region SR1:
Thickness of 1 to 5 pm / impurity concentration of 1 x 1016 to 1018 cm-3 Fifth semiconductor region SR2:
Thickness of 1 to 5 μm / impurity concentration of 1 × 10 16 to 10 18 cm -3 In the insulating layer 1E, contact holes (not illustrated in the figure) arranged to expose the surfaces of the first to third semiconductor regions FD1 -i to FD32 are arranged are used. Inside the contact holes are. Conductor (not illustrated in the figure) arranged to connect the first to third semiconductor regions FDI-i to FD32 to the outside.
When a high level signal (positive electric potential) is applied to the first gate electrodes TXI-i and TX12, the potential of regions just below the first gate electrodes TX1i and TX12 becomes lower than that of an area just below the photo-gate. Gate electrode PG1 of the semiconductor substrate 1A. Accordingly, the negative electric charge (electron) is attracted in the directions of the first gate electrodes TXI-i and TX12 and is accumulated within potential wells formed by first semiconductor regions FD11 and FD12, the first gate electrodes TXI-i and TX12 cause a signal charge to flow into the first semiconductor regions FD11 and FD12 according to an input signal. The n-type semiconductor contains positively ionized donors, has a positive potential and attracts electrons. When a low level signal (eg, a grounded electric potential) is applied to the first gate electrodes TXI-i and TX12 TXI-i, potential walls are formed according to the first gate electrodes TXI-i and TX12. Accordingly, an electric charge generated in the semiconductor substrate 1A is not attracted to the respective interior of the first semiconductor regions FDI-1 and FD12.
When a high-level signal is applied to the second gate electrodes TX2-, and TX22, the potential of regions just below the second gate electrodes TX2-I and TX22 becomes lower than that of the region just below the photo-gate electrode PG1 of the semiconductor substrate 1A. Accordingly, a negative electric charge in the directions of the second gate electrodes TX2- |. and TX22 and is accumulated within potential wells formed by the second semiconductor regions FD2-I and FD22. The second gate electrodes TX2-I and TX22 cause a signal charge to flow into the second semiconductor regions FD2-I and FD22 according to an input signal. When a low-level signal is applied to the second gate electrodes TX2-I and TX22, potential walls are formed in accordance with the second gate electrodes TX2- | and TX22. Accordingly, an electric charge generated in the semiconductor substrate 1A is not attracted to the respective interior of the second semiconductor regions FD2-I and FD22.
When a high level signal is applied to the third gate electrodes TX3-I and TX32, the potential of areas just below the third gate electrodes TX3-, and TX32 becomes lower than that of the area just below the photo gate electrode PG1 of the semiconductor substrate 1A. Accordingly, a negative electric charge is attracted in the directions of the third gate electrodes TX3i and TX32 and is discharged through potential wells formed by the third semiconductor regions FD3i and FD32. When a low-level signal is applied to the third gate electrodes TX3i and TX32, potential walls are formed in accordance with the third gate electrodes TX3i and TX32. Accordingly, an electric charge generated in the semiconductor substrate 1A is not attracted to the respective interior of the third semiconductor regions FD3-I and FD32. Part of the electric charge generated in the electric charge generating regions according to the incidence of the light is discharged to the third semiconductor regions FD3-I and FD32 as unnecessary electric charge.
The detection pulse light LD from the target object incident from the light incident surface 1 FT of the semiconductor substrate 1A reaches the light receiving region (electric charge generation region) on the front side of the semiconductor substrate 1A. The electric charge generated inside the semiconductor substrate 1A according to the incidence of the detection pulse light Ld is applied from the electric charge generating region to the regions just below the first gate electrodes TXI-i and TX12 or the second gate electrodes TX2- I and TX22 adjacent to the electric charge generation region. In other words, when a detection gate signal Si synchronized with the pulse driving signal Sp of the light source is applied to the first gate electrodes TXI-i and TX12 through the wiring board 10, an electric charge generated in the electric charge generating regions flows into the regions just below the first gate electrodes TXI-i and TX12 and flows therefrom into the first semiconductor regions FD1-I and FD12. When a detection gate signal S2 having a phase different from that of the pulse driving signal SP of the light source and the detection gate signal S-ι is applied to the second gate electrodes TX2-I and TX22 through the wiring board 10, an in The electric charge generating regions generated in the electric charge generating regions in the areas just below the second gate electrodes TX2-I and TX22 and flows thereof into the second semiconductor regions FD2-I and FD22.
Although not shown in the figure, the distance image sensor 1 includes a backside gate semiconductor region used for fixing the electric potential of the semiconductor substrate 1A to an electrical reference potential.
Figs. 8 and 9 are diagrams illustrating potential distributions for describing operations for accumulating an electric charge. 10 is a diagram illustrating a potential distribution for describing an operation for discharging an electric charge. Here, (a) illustrates potential distributions on a line taken along a line VV illustrated in FIG. 4 from FIG. 8 to FIG. 10, illustrating (b) of FIG. 8 to FIG. 10 potential distributions on one along one shown in FIG. 4 Line Vl-Vl taken cross section, and illustrates (c) of Fig. 8 to Fig. 10 potential distributions on a taken along a line VII-VII illustrated in Fig. 4 cross-section.
When light is incident, the potential rpPG1 of the electric charge generating region is set to be slightly higher than the reference potential by an electric potential applied to the photo-gate electrode PG1 (for example, an intermediate electric potential between a highest electric potential and a lowest electric potential under electric potentials applied to the first to third gate electrodes TX1-I to TX32). In each figure, the potentials φΤΧ1 · ι and φΤΧ12 of the regions just below the first gate electrodes TXI-i and TX12 are the potentials φ ΤΧ2 · ι and φΤΧ22 of the regions just below the second gate electrodes TX2-I and TX22, the potentials φΤΧ3ι and φΤΧ32 of the regions just below the third gate electrodes TX3i and TX32, the potentials (pFD1-i and rpFD12 of the first semiconductor regions FDI-i and FD12, the potentials (pFD2-i and rpFD22 of the second semiconductor regions FD2-I and FD22, the potentials rpFD3i and rpFD32 of the third semiconductor regions FD3i and FD32 and the potential rpSR1 of the fourth semiconductor region SR1 are illustrated.
A detection gate signal S1 is applied to the first gate electrodes TXI-i and TX12 as a charge transfer signal. When the high electric potential of the detection gate signal S1 is input to the first gate electrodes TXI-i and TX12, as illustrated in (a) of Fig. 8, one in the electric charge generation region (the area is straight below the photo gate electrode PG1), electric charges are accumulated in potential wells of the first semiconductor regions FDI-i and FD12 through the regions just below the first gate electrodes TXI-i and TX12 along a potential gradient. Within the potential wells of the first semiconductor regions FDI-1 and FD12, the amount of electric charge Q1 is accumulated in accordance with a pulse timing of the detection gate signal S1. A voltage output V0uti corresponding to the accumulated electric charge amount Q1 is read from the first semiconductor regions FDI-1 and FD12. The voltage output Vout1 corresponds to the signal d-i described above.
At this time, in the area just below the photo gate electrode PG1, the potential cpSR1 of the fourth semiconductor region SR1 positioned at a center portion in the X direction is higher than the potential of the first longer side sides rpPG1 LS1 and the second longer side LS2. Accordingly, in the area just below the photo gate electrode PG1, a high potential region extending in the Y direction is formed between the first longer side LS1 and the second longer side LS2, and a much steeper gradient of the potential different from that of FIG of the fourth semiconductor region SR1 is reduced to the first longer side LS1 and the second longer side LS2.
The electric charge generated in the electric charge generating region moves nimbly to the first semiconductor region FDI-1 on the side of the first longer side LS1 and the first semiconductor region FD12 on the side of the second longer side LS2 according to the potential gradient described above formed by the fourth semiconductor region SR1.
As illustrated in (b) and (c) of Fig. 8, while the detection gate signal S1 is applied to the first gate electrodes TXI-i and TX12, a low-level electric potential (e.g., grounded electric Potential) are applied to the second gate electrodes TX2-I and TX22 and third gate electrodes TX3-I and TX32. Accordingly, the potentials (pTX2 ·· and TX22 and the potentials φΤΧ3-ι and TX32 are not reduced, and an electric charge does not flow into the respective interior of the potential wells of the second semiconductor regions FD2-I and FD22 and the third semiconductor regions FD3i and FD32.
E in detection gate signal S2 is applied to second gate electrodes TX2-I and TX22 as a charge transfer signal. When the high electric potential of the detection gate signal S2 is input to the second gate electrodes TX2-I and TX22, as illustrated in (b) of Fig. 9, an electric charge generated in the electric charge generation region becomes Potential wells of the second semiconductor regions FD2-I and FD22 through the areas just below the second gate electrodes TX2-I and IX22 accumulated along a potential gradient. Within the potential wells of the second semiconductor regions FD2-I and FD22, the electric charge amount Q2 is accumulated according to a pulse timing of the detection gate signal S2. A voltage output Vout2 corresponding to the accumulated electric charge amount Q2 is read from the second semiconductor regions FD2-I and FD22. The voltage output Vout2 corresponds to the signal d2 described above.
The electric charge generated in the electric charge generating region rapidly moves to the second semiconductor region FD2-I on the side of the first longer side LS1 and the second semiconductor region FD22 on the side of the second longer side LS2 according to the potential gradient described above formed by the fourth semiconductor region SR1.
As illustrated in (a) and (c) of FIG. 9, while the detection gate signal S2 is applied to the second gate electrodes TX2-I and TX22, a low-level electric potential is applied to the first gate electrodes. Electrodes ΤΧΉ and TX12 and third gate electrodes TX3i and TX32 applied. Accordingly, the potentials φΤΧ1-ι and TX12 and the potentials φΤΧ3-ι and TX32 are not reduced, and an electric charge does not flow into the respective interior of the potential wells of the first semiconductor regions FD1- | and FD12 and the third semiconductor regions FD3 | and FD32.
A discharge gate signal S3 is applied to the third gate electrodes TX3i and TX32. When the high electric potential of the discharge gate signal S3 is input to the third gate electrodes TX3i and TX32, as illustrated in (c) of FIG. 10, an electric charge generated in the electric charge generating region flows into the respective one Inside the potential wells of the third semiconductor regions FD3-I and FD32 through the areas just below the third gate electrodes TX3-i and TX32 along the potential gradient as a superfluous electrical charge. The superfluous electric charge flowing into the potential wells of the third semiconductor regions FD3i and FD32 is discharged to the outside. While a positive electric potential is applied to the third gate electrodes TX3i and TX32, a low level electric potential is applied to the first gate electrodes TXI-i and TX12 and the second gate electrodes TX2-I and TX22. Accordingly, as illustrated in (a) and (b) of Fig. 10, the potentials φΤΧ1 · ι and TX12 and the potentials φΤΧ2 · ι and TX22 are not reduced, and an electric charge does not flow into the respective interior of the potential wells of the first one Semiconductor regions FDI-i and FD12 and the second semiconductor regions FD2-I and FD22.
Fig. 11 is a timing chart of various signals.
A frame period is configured by a duration during which a signal charge is accumulated (accumulation period), and a period during which the signal charge is read (read period). When a distance sensor P1 is observed during the accumulation period, a signal based on a pulse drive signal Sp is applied to the light source, and a detection gate signal S1 becomes in synchronization with the first gate electrodes TXI-i and TX12 created. Subsequently, a detection gate signal S2 is applied to the second gate electrodes TX2-I and TX22 with a predetermined phase difference from the detection gate signal S-1 (for example, a phase difference of 180 degrees). In other words, charge transfer signals having phases different from each other are applied to the first and second gate electrodes ΤΧΤ and TX2-I on the first longer side LS1 side, and the charge transfer signals having phases different from each other are applied to the first and second gate electrodes TX12 and TX22 are applied on the second longer LS2 side. Before the distance is measured, a reset signal is applied to the first and second semiconductor regions FDI-i to FD22, and an internal charge accumulated in the interior is discharged to the outside. After the reset signal is in the on state for a moment and then continuously in the off state, pulses of the sense gate signals S1 and S2 are sequentially applied to the first and second gate electrodes TXI-i to TX22 , and an electric charge is transferred. Then, the signal charge is added up to be accumulated within the first and second semiconductor regions FD1 -i to FD22.
Thereafter, during a reading period, accumulated signal charges are read within the first and second semiconductor regions FD11 to FD22. At this time, the discharge gate signal S3 applied to the third gate electrodes TX3i and TX32 is in the high level, positive electric potentials are applied to the third gate electrodes TX3i and TX32, and an unnecessary electric charge becomes in the potential wells of the third semiconductor regions FD3-I and FD32.
An electric potential VPG applied to the photo-gate electrode PG1 is set to be lower than the electric potentials VTXI1, V TX12, VTX2-I, VTX22, VTX3i and VTX32. Accordingly, when the detection gate signals S-1 and S3 become high level, the potentials φΤΧ1 · ι, φΤΧ12, φΤΧ2 · ι, φΤΧ22 are lower than the potential rpPG1. When the discharge gate signal S3 reaches the high level, the potentials φΤΧ3-ι and φΤΧ32 are lower than the potential rpPG1.
The electric potential VPG is set to be higher than the electric potential at a time when the detection gate signals S1 and S2 and the discharge gate signal S3 are in the low level. When the detection gate signals S-1 and S2 reach the low level, the potentials φΤΧ1 · ι, φΤΧ12, φΤΧ2-ι and φΤΧ22 are higher than the potential rpPG1. When the discharge gate signal S3 reaches the low level, the potentials φΤΧ3-ι and φΤΧ32 are higher than the potential rpPG1.
It is assumed that the pulse width of each of the pulse signals SP, S-i, S2 and SD is TP. When the detection gate signal S-1 synchronized with the pulse drive signal SP is at the high level, and the pulse detection signal SD is at the high level, the amount of electric charge generated within the distance sensor P1 (which is within the first semiconductor regions FD1-S) is high. When the detection gate signal S2 having a phase difference of 180 degrees from the pulse drive signal SP is in the high level, and the pulse detection signal SD is in the high level, the amount of electric charge inside the distance sensor P1 is .theta.1 and FD12 accumulated electric charge quantity Q1 is generated (the charge amount Q2 accumulated within the second semiconductor regions FD2-I and FD22.
A phase difference between the detection gate signal Si and the pulse detection signal So (a phase difference between the emission pulse light LP and the detection pulse light LD) is proportional to the electric charge amount Q2 described above. When a total electric charge amount generated within one pixel is Q1 + Q2, the pulse detection signal SD lags behind a duration of At = TP × Q2 / (Q1 + Q2) after the pulse drive signal SP. When a distance to the target object is d, and the speed of light is c, the propagation time At of a pulse light is given as At = 2d / c. For this reason, when two electric charge quantities Q1 and Q2 are output as signals di and d2 with distance information from a specific pixel, the duty circuit 5 calculates the distance d to the target object H by using d = (cxAt) / 2 = cxTPxQ2 / (2x (Q1 + Q2)) based on the input electric charge quantities Q1 and Q2 and the predetermined pulse width TP.
As described above, by separately reading the electric charge amounts Q1 and Q2, the duty circuit 5 can calculate the distance d. Note that the above-described pulse is repeatedly output, and integral values thereof can be output as the electric charge quantities Q1 and Q2.
The ratios of the electric charge quantities Q1 and Q2 to a total electric charge amount correspond to the phase difference described above, in other words, a distance up to the target object H. The duty circuit 5 calculates a distance up to the target object H according to the phase difference. As described above, when a time difference Δt corresponding to the phase difference is given, the distance d is preferably given as d = (c x At) / 2. An appropriate correction operation may be added to the calculation described above. In an exemplary case where an actual distance and the calculated distance d are different from each other, it may be arranged such that a calculated distance corrective coefficient β is acquired in advance, and a final calculated distance d is acquired by multiplying the calculated distance d with the coefficient β in a product after shipment. In addition, it may be arranged to measure an outside air temperature, and in a case where the speed of light differs according to the outside air temperature, after a calculation for correcting the speed of light c is performed, the distance calculation is performed. Moreover, it may be arranged such that a relation between a signal inputted to the working circuit and an actual distance is stored in a memory in advance, and the distance is calculated using a look-up table method. The calculation method may be changed based on the sensor structure, and a calculation method conventionally known may be used therefor.
As above, in the distance sensor P1 of the distance image sensor 1 according to this embodiment, a high potential is generated in the area just below the fourth semiconductor region SR1 positioned between the first longer side LS1 and the second longer side LS2 of the light receiving area, and a slope of the potential is formed between the first longer side LS1 and the second longer side LS2. Accordingly, under signal charges generated according to the incoming light, a signal charge generated in a region just below a portion of the photo gate electrode PG1 on the first longer side LS1 side is accelerated to the first longer side LS1, and a signal charge which has been generated in a region just below a portion of the photo-gate electrode PG1 on the side of the second longer side LS2 is accelerated to the second longer side LS2. Thus, the transfer speed can be improved.
In the distance sensor P1, a high potential is generated between the first longer side LS1 and the second longer side LS2, and a slope of the potential is formed to both the first longer side LS1 and the second longer side LS2. For example, the moving distance of the signal charge is shorter than that of a case where the first and second gate electrodes TX1 and TX2 are arranged along only one of the first and second longer sides LS1 and LS2, and a slope of the potential of the other of the first and second longer sides LS1 and LS2 are formed to the one of them. Accordingly, the transfer speed can be improved.
Since the fourth semiconductor region SR1, which is a potential adjusting means, is common through the area just below the portion of the photo gate electrode PG1 on the side of the first longer side LS1 and the area just below the portion of the photo gate electrode PG1 is used on the side of the second longer side LS2, the utilization efficiency of the area is improved. Accordingly, the aperture ratio can be improved.
The charge transfer signals S-ι and S2 having phases different from each other are input to the plurality of first-side transfer electrodes (TX1i and TX2- |), and the charge transfer signals S-ι and S2 having the phases different from each other also become input to the plurality of second-side transfer electrodes (TX12 and TX22). Thus, even if any one of the charge transfer signals Si and S2 is given, the signal charges in the area just below the portion of the photo-gate electrode PG1 on the side of the first longer one can be
Side LS1 and also the area just below the portion of the photo-gate electrode PG1 on the side of the second longer side LS2 have been acquired. Accordingly, a disturbance in the collection of the signal charge is reduced, and the transfer accuracy can be improved.
Since the charge transfer signals Si and S2 having mutually different phases are input to the plurality of Ers-th side transfer electrodes (TX1i and TX2-i), and the charge transfer signals Si and S2 having the phases different from each other are also applied to the Plurality of second-side transfer electrodes (TX12 and TX22) are inputted, the influence of manufacturing variations in the X direction, in which the first longer side LS1 and the second longer side LS21 face each other, can be reduced to be smaller than that of a case where only one-phase charge transfer signals are input to the first-side transfer electrode and the second-side transfer electrode, respectively. Accordingly, the transfer accuracy can be improved.
Since the distance sensor P1 includes the third semiconductor regions FD3i and FD32 and the third gate electrodes TX3i and TX32 on the sides of the first longer side LS1 and the second longer side LS2, unnecessary electric charge can be discharged, and accordingly the transfer accuracy can be improved.
Since the light receiving region includes the first region and the second region, and the potential adjusting device is the fourth semiconductor region SR1 having a high impurity concentration disposed between the first region and the second region, a high potential can be generated using a simple configuration.
Next, the configuration of a distance sensor according to another embodiment will be described. Fig. 12 is a plan view illustrating a part of the distance sensor according to another embodiment.
As illustrated in FIG. 12, a distance sensor P2 according to this embodiment differs in that the number of third semiconductor regions FD3-I and FD32 and the third gate electrodes TX3-I and TX32 is smaller compared to the distance sensor described above P1 (see Fig. 4).
In the distance sensor P2, the third semiconductor region FD3-I is alternately arranged between the first semiconductor region FD1 -i and the second semiconductor region FD2-I in the Y-direction, and the third semiconductor region FD32 is alternately interposed between the first semiconductor region FD12 and the first semiconductor region FD32 second semiconductor region FD22 arranged in the Y direction. The third semiconductor regions FD3i and FD32 may be arranged at both ends in the Y direction. The third gate electrode TX3i is alternately arranged between the first gate electrode TXI-i and the second gate electrode TX2-I in the Y direction, and the third gate electrode TX32 is alternately connected between the first gate electrode TX12 and the second gate electrode TX22 arranged in the Y direction.
In the distance sensor P2 according to this embodiment, since a slope of the potential is formed from the area just below the fourth semiconductor region SR1 to the first longer side LS1 and the second longer side LS2, the transfer speed can be improved.
Since the fourth semiconductor region SR1, which is a potential adjusting means, is shared by the area just below the portion of the photo gate electrode PG1 on the side of the first longer side LS1 and the area just below the portion of the photo gate Electrode PG1 on the side of the second longer side LS2, the use efficiency of the area is improved. Accordingly, the aperture ratio can be improved.
Since the charge transfer signals S-1 and S2 are input to the plurality of Ers-th-side transfer electrodes (TX1 -i and TX2- |) with mutually different phases, and the charge transfer signals S-1 and S2 to each other discriminating phases are also input to the plurality of second-side transfer electrodes (TX12 and TX22), a noise in the collection of the signal charge is reduced, and the influence of manufacturing variations in the X-direction is reduced. Accordingly, the transfer accuracy can be improved.
Since the distance sensor P2 includes the third semiconductor regions FD3-I and FD32 and the third gate electrodes TX3-I and TX32 on the side of the first longer side LS1 and the side of the second longer side LS2, unnecessary electric charge can be generated be discharged. Accordingly, the transfer accuracy can be improved.
Since the light receiving region includes the first region and the second region, and the potential adjusting device is the fourth semiconductor region SR1 having a high impurity concentration disposed between the first region and the second region, a high potential can be generated using a simple configuration.
Next, the configuration of a distance sensor according to still another embodiment will be described. Fig. 13 is a plan view illustrating a part of the distance sensor according to still another embodiment.
As illustrated in FIG. 13, a distance sensor P3 according to this embodiment differs in that it does not include the third semiconductor regions FD3i and FD32 and the third gate electrodes TX3i and TX32 in comparison with the above-described distance sensor P1 (see FIG. 4).
In the distance sensor P3 according to this embodiment, since the slope of the potential is formed from the area just under the fourth semiconductor region SR1 to the first longer side LS1 and the second longer side LS2, the transfer speed can be improved.
Since the fourth semiconductor region SR1, which is a potential adjusting means, is shared by the area just below the portion of the photo gate electrode PG1 on the side of the first longer side LS1 and the area just below the portion of the photo gate Electrode PG1 on the side of the second longer side LS2, the use efficiency of the area can be improved. Accordingly, the aperture ratio can be improved.
Since the charge transfer signals Si and S2 having phases different from each other are input to the plurality of Ers-th-side transfer electrodes (TX1 -i and TX2- |), and the charge transfer signals S-1 and S2 having phases different from each other are also input to the plurality of second-side transfer electrodes (TX12 and TX22), a noise in the collection of the signal charge is reduced, and the influence of manufacturing variations in the X direction is reduced. Accordingly, the transfer accuracy can be improved.
Since the light receiving region includes the first region and the second region, and the potential adjusting device is the fourth semiconductor region SR1 having a high impurity concentration disposed between the first region and the second region, a high potential can be generated using a simple configuration.
Next, the configuration of a distance sensor according to another embodiment will be described. Fig. 14 is a plan view illustrating a part of a distance sensor according to still another embodiment.
As illustrated in FIG. 14, a distance sensor P4 according to this embodiment differs in that the arrangement of the semiconductor regions and the electrodes is different between the side of the first longer side LS1 and the side of the second longer side LS2 compared to the side Distance sensor P1 described above (see Fig. 4).
In the distance sensor P4, the first gate electrode TXI-i and the second gate electrode TX22, to which charge transfer signals having phases different from each other are applied, oppose in the X direction, and the second gate electrode TX2 -i and the first gate electrode TX12, to which the charge transfer signals having mutually different phases are applied, are opposed to each other in the X direction. Accordingly, the input positions of the detection gate signals S-1 and S2 are different between the side of the first longer side LS1 and the side of the second longer side LS2. The first semiconductor region FDI-i and the second semiconductor region FD22 face each other in the X direction, and. the second semiconductor region FD2-I and the first semiconductor region FD12 face each other in the X direction.
In the distance sensor P4 according to this embodiment, since the slope of the potential is formed from the area just below the fourth semiconductor region SR1 to the first longer side LS1 and the second longer side LS2, the transfer speed can be improved.
Since the fourth semiconductor region SR1, which is a potential adjusting means, is shared by the area just below the portion of the photo gate electrode PG1 on the side of the first longer side LS1 and the area just below the portion of the photo gate Electrode PG1 on the side of the second longer side LS2, the use efficiency of the area is improved. Accordingly, the aperture ratio can be improved.
Since the charge transfer signals S1 and S2 having phases different from each other are input to the plurality of Ers-th-side transfer electrodes (TXI-i and TX2- |), and the charge transfer signals S-1 and S2 are different from each other Also, if phases are input to the plurality of second-side transfer electrodes (TX12 and TX22), interference in the collection of the signal charge is reduced, and the influence of manufacturing variations in the X direction is reduced. Accordingly, the transfer accuracy can be improved.
The gate electrodes are arranged so that the first gate electrode TXI-i and the second gate electrode TX22, to which charge transfer signals having phases different from each other are applied, oppose each other in the X direction, and the second one Gate electrode TX2-I, and the first gate electrode TX12, to which charge transfer signals having phases different from each other are applied, face each other in the X direction. Accordingly, input positions of the same phase detection gate signals are different between the first longer side LS1 side and the second longer side LS2 side. For this reason, the dependence on the input positions of the detection gate signals can be balanced. Accordingly, the transfer accuracy can be improved.
Since the distance sensor P4 includes the third semiconductor regions FD3i and FD32 and the third gate electrodes TX3i and TX32 on the side of the first longer side LS1 and the side of the second longer side LS2, unnecessary electric charge is discharged. Accordingly, the transfer accuracy can be improved.
Since the light receiving region includes the first region and the second region, and the potential adjusting device is the fourth semiconductor region SR1 having a high impurity concentration disposed between the first region and the second region, a high potential can be generated using a simple configuration.
Next, the configuration of a distance sensor according to still another embodiment will be described. Fig. 15 is a plan view illustrating a part of the distance sensor according to still another embodiment.
As illustrated in FIG. 15, a distance sensor P5 according to this embodiment differs in that the arrangement of the semiconductor regions and the electrodes is different between the side of the first longer side LS1 and the side of the second longer side LS2, as compared with FIG the above-described distance sensor P2 (see Fig. 12).
In the distance sensor P5, the first gate electrode TX1i and the second gate electrode TX22, to which charge transfer signals having phases different from each other are applied, face each other in the X direction, and the second gate electrode TX2-I and the first gate electrode TX12, to which the charge transfer signals having mutually different phases are applied, oppose each other in the X direction. Accordingly, the input positions of the detection gate signals Si and S2 are different between the side of the first longer side LS1 and the side of the second longer side LS2. The first semiconductor region FD11 and the second semiconductor region FD22 face each other in the X direction, and the second semiconductor region FD2-I and the first semiconductor region FD12 face each other in the X direction. In the distance sensor P5 according to this embodiment, since the slope of the potential is formed from the area just below the fourth semiconductor region SR1 to the first longer side LS1 and the second longer side LS2, the transfer speed can be improved.
Since the fourth semiconductor region SR1, which is a potential adjusting means, is shared by the area just below the portion of the photo gate electrode PG1 on the side of the first longer side LS1 and the area just below the portion of the photo gate Electrode PG1 on the side of the second longer side LS2, the use efficiency of the area is improved. Accordingly, the aperture ratio can be improved.
Since the charge transfer signals S-, and S2 are input to the plurality of Ers-th-side transfer electrodes (TXI-i and TX2- |) with phases different from each other, and the charge transfer signals S-1 and S2 with the thus, inputting to the plurality of second-side transfer electrodes (TX12 and TX22) are also reduced, disturbance in the collection of the signal charge is reduced, and the influence of manufacturing variations in the X-direction is reduced. Accordingly, the transfer accuracy can be improved.
The gate electrodes are arranged so that the first gate electrode TXI-i and the second gate electrode TX22, to which charge transfer signals having mutually different phases are applied, face each other in the X direction, and the second one Gate electrode TX2-I and the first gate electrode TX12, to which charge transfer signals having phases different from each other are applied, face each other in the X direction. Accordingly, input positions of the same phase detection gate signals are different between the first longer side LS1 side and the second longer side LS2 side. For this reason, the dependence on the input positions of the detection gate signals can be balanced. Accordingly, the transfer accuracy can be improved.
Since the light receiving region includes the first region and the second region, and the potential adjusting device is the fourth semiconductor region SR1 having a high impurity concentration disposed between the first region and the second region, a high potential can be generated using a simple configuration.
Next, the configuration of a distance sensor according to still another embodiment will be described. 16 is a plan view illustrating a part of the distance sensor according to still another embodiment.
As illustrated in FIG. 16, a distance sensor P6 according to this embodiment differs in that the positions of the semiconductor regions and the electrodes differ between the side of the first longer side LS1 and the side of the second longer side LS2, compared to FIG Distance sensor P2 described above (see Fig. 12).
In the distance sensor P6, the positions of the first and second gate electrodes TXI-i and TX22 are disposed on the first longer side LS1 side and the first and second gate electrodes TX12 and TX22 on the second longer side LS2 side to deviate with each other in the Y direction. Accordingly, the input positions of the detection gate signals S-1 and S2 are different between the side of the first longer side LS1 and the side of the second longer side LS2. The positions of the first and second semiconductor regions FD11 and FD2-I on the first longer side LS1 side and the first and second semiconductor regions FD12 and FD22 on the second longer side LS2 side are arranged to deviate from each other in the Y direction.
In the distance sensor P6 according to this embodiment, since the slope of the potential is formed from the area just below the fourth semiconductor region SR1 to the first longer side LS1 and the second longer side LS2, the transfer speed can be improved.
Since the fourth semiconductor region SR1, which is a potential adjusting means, is shared by the area just below the portion of the photo gate electrode PG1 on the side of the first longer side LS1 and the area just below the portion of the photo gate Electrode PG1 on the side of the second longer side LS2, the use efficiency of the area is improved. Accordingly, the aperture ratio can be improved.
Since the charge transfer signals S-ι and S2 are input to the plurality of Ers-th-side transfer electrodes (TX1 -i and TX2- |) with mutually different phases, and the charge transfer signals S-ι and S2 to each other discriminating phases are also input to the plurality of second-side transfer electrodes (TX12 and TX22), a noise in the collection of the signal charge is reduced, and the influence of manufacturing variations in the X-direction is reduced. Accordingly, the transfer accuracy can be improved.
Since the first and second gate electrodes TX1i, and TX2-I are disposed on the first longer side LS1 side, and the first and second gate electrodes TX12 and TX22 on the second longer side LS2 side are in positions are different from each other in the Y direction in which the first and second longer sides LS1 and LS2 extend, the positions of the charge transfer signals having the same phase are different between the side of the first longer side LS1 and the side of the second longer side LS2 , For this reason, the dependence on the input positions of the charge transfer signals can be compensated. Accordingly, the transfer accuracy can be improved.
Since the distance sensor P6 includes the third semiconductor regions FD3-I and FD32 and the third gate electrodes TX3 ·, and TX32 on the side of the first longer side LS1 and the side of the second longer side LS2, respectively, unnecessary electric charge can be generated be discharged. Accordingly, the transfer accuracy can be improved.
Since the light receiving region includes the first region and the second region, and the potential adjusting device is the fourth semiconductor region SR1 having a high impurity concentration disposed between the first region and the second region, a high potential can be generated using a simple configuration.
Next, the configuration of a distance sensor according to still another embodiment will be described. Fig. 17 is a plan view illustrating a part of the distance sensor according to still another embodiment.
As illustrated in FIG. 17, a distance sensor P7 according to this embodiment differs in that fourth gate electrodes TX4-I and TX42 having a shape different from those of the first gate electrodes TXI-i and TX12 are included instead of first gate electrodes TXI-i and TX12, and fifth gate electrodes TX5-I and TX52 having a shape different from that of the second gate electrodes TX2-I and TX22 are included instead of the second gate electrodes TX2-I and TX22, in comparison with the above-described distance sensor P2 (see Fig. 12).
On the side of the first longer side LS1, a plurality of pairs of the fourth gate electrode TX4-, and the fifth gate electrode TX5-I are formed adjacent to each other in the Y direction in the Y direction, and on the side of the longer side LS2 are a plurality of pairs of the fourth gate electrode TX42 and the fifth gate electrode TX52 adjacent to each other in the Y direction formed in the Y direction. Between these pairs on the side of the first longer side LS1, the third gate electrode TX3i is arranged, and between the pairs on the side of the second longer side LS2, the third gate electrode TX32 is arranged.
Each of the fourth and fifth gate electrodes TX4-I to TX52 shows an "L" shape in plan view. Each of the fourth and fifth gate electrodes TX4-I to TX52 includes a first portion TX10 and a second portion TX20. The first portion TX10 extends in the Y direction and shows a rectangular shape with the Y direction as its longer-side direction in plan view. The second portion TX20 extends in the X direction from an end portion of the first portion TX10, more distant from the adjacent portion TX10, and shows a rectangular shape with the X direction as its longer-side direction in the plan view. The second portion TX20 includes a portion that overlaps the light receiving area in the plan view.
The photo gate electrode PG1 shows a shape with recessed portions to avoid the fourth and fifth gate electrodes TX4-I to TX52 for each longer side in the plan view. The second section TX20 is surrounded by the photo-gate electrode PG1 in plan view. More specifically, the second portion TX20 is surrounded by the photo gate electrode PG1 over three sides included in the edge of the second portion TX20.
As described above, in the light receiving area of the semiconductor substrate 1A, the area corresponding to the photo gate electrode PG1 (the area just below the photo gate electrode PG1) serves as an electric charge generating region in which electric charge is generated according to the incident light. Since the fourth and fifth gate electrodes TX4-I to TX52 are formed using polysilicon, light is transmitted through the second portions TX20 of the fourth and fifth gate electrodes TX4-I to TX52 and is incident on the semiconductor substrate 1A. Accordingly, a region of the semiconductor substrate 1A just below the second portion TX20 also serves as an electric charge generation region. Thus, in this embodiment, in plan view, the shape of the light receiving area and the shape of the electric charge generating region coincide with each other. The second section TX20 is positioned to overlap also the electric charge generating region. In a case where the fourth and fifth gate electrodes TX4-I to TX52 are formed using a material that does not transmit light, the electric charge generating region is defined by the photo gate electrode PG1, and the shape of the The light receiving area and the shape of the electric charge generating region are not coincident with each other.
In the distance sensor P7 according to this embodiment, since the slope of the potential is formed from the area just below the fourth semiconductor region SR1 to the first longer side LS1 and the second longer side LS2, the transfer speed can be improved.
Since the fourth semiconductor region SR1, which is a potential adjusting device, is shared by the area just below the portion of the photo gate electrode PG1 on the side of the first longer side LS1 and the area just below the portion of the photo gate Electrode PG1 on the side of the second longer side LS2, the use efficiency of the area is improved. Accordingly, the aperture ratio can be improved.
Since the charge transfer signals Si and S2 having phases different from each other are input to the plurality of Ers-th-side transfer electrodes (TX4-I and TX5-i), and the charge transfer signals S-1 and S2 are different from each other Also, if phases are input to the plurality of second-side transfer electrodes (TX42 and TX52), interference in the collection of the signal charge is reduced, and the influence of manufacturing variations in the X direction is reduced. Accordingly, the transfer accuracy can be improved.
Since the distance sensor P7, the third semiconductor regions FD3- | and FD32 and the third gate electrodes TX3- | and TX32 includes on the side of the first longer side LS1 and the side of the second longer string LS2, a superfluous electric charge can be discharged. Accordingly, the transfer accuracy can be improved.
Since the light receiving region includes the first region and the second region, and the potential adjusting device is the fourth semiconductor region SR1 having a high impurity concentration disposed between the first region and the second region, a high potential can be generated using a simple configuration.
A plurality of transfer electrodes on the first longer side LS1 side include pairs of the fourth gate electrode TX4- | and the fifth gate electrode TX5-I to which signals having mutually different phases are applied adjacent to each other in the Y direction, and a plurality of transfer electrodes on the longer side LS2 side include pairs of the fourth gate electrodes TX42 and of the fifth gate electrode TX52 to which signals having phases different from each other are applied adjacent to each other in the Y direction. Each of the fourth and fifth gate electrodes TX4-I to TX52 includes the first portion TX10 extending along the Y direction and the second portion TX20 extending to the light receiving area from the end portion of the first portion TX10 to overlap, which is located farther from the adjacent first portion TX10. When a signal charge is transferred in a region just below the transfer electrode which does not transfer the signal charge from the pair of transfer electrodes, the potential can be raised. Thus, in the light receiving area, a slope of the potential from the area just below the second portion TX20 of the transfer electrode that does not transfer a signal charge occurs along the Y direction, and the signal charge moves rapidly in the Y direction. Accordingly, the transfer speed can be improved. In particular, for a configuration that is long in the Y direction, similar to the distance sensor P7, the advantages of this embodiment can be suitably acquired.
Next, the configuration of a distance sensor according to still another embodiment will be described. Fig. 18 is a plan view illustrating a part of the distance sensor according to still another embodiment.
As illustrated in FIG. 18, a distance sensor P8 according to this embodiment differs in that sixth gate electrodes ΤΧΘ-ι and TX62 having a shape different from those of the third gate electrodes TX3a and TX32 are substituted for the third gate Electrodes TX3i and TX32, as compared with the above-described distance sensor P2 (see FIG. 12).
Each of the sixth gate electrodes TX6-1 and TX62 shows a "T" shape in plan view. Each of the sixth gate electrodes TX6-1 and TX62 includes a third portion TX30 and a fourth portion TX40. The third portion TX30 extends in the Y direction and shows a rectangular shape with the Y direction as its longer-side direction in the plan view. The fourth portion TX40 extends from the Y-direction center portion of the third portion TX30 in the X direction, and shows a rectangular shape with the X direction as its longer-side direction in the plan view. The fourth portion TX40 has a portion that overlaps the light receiving area in the plan view.
The photo gate electrode PG1 shows a shape having recessed portions to avoid the fourth portions TX40 of the sixth gate electrodes TX61 and TX62 for each longer side in the plan view. The fourth section TX40 is surrounded by the photo-gate electrode PG1 in plan view. More specifically, the fourth portion TX40 is surrounded by the photo gate electrode PG1 over three sides included in the edge of the fourth portion TX40.
As described above, in the light receiving area of the semiconductor substrate 1A, the area corresponding to the photo gate electrode PG1 (the area just below the photo gate electrode PG1) serves as an electric charge generating region in which a electric charge is generated according to the incident light. Since the sixth gate electrodes TX61 and TX62 are formed using polysilicon, light is transmitted through the fourth portions TX40 of the sixth gate electrodes TX6-1 and TX62 and is incident on the semiconductor substrate 1A. Accordingly, a region of the semiconductor substrate 1A just below the fourth portion TX40 also serves as an electric charge generation region. Thus, in this embodiment, in plan view, the shape of the light receiving area and the shape of the electric charge generating region coincide with each other. The fourth section TX40 is positioned to overlap also the electric charge generating region. In a case where the sixth gate electrodes TX61 and TX62 are formed using a material that does not transmit light, the electric charge generating region is defined by the photo gate electrode PG1 and the shape of the light receiving area and the shape of the electric charge generation region do not coincide with each other.
In the distance sensor P8 according to this embodiment, since the slope of the potential is formed from the area just below the fourth semiconductor region SR1 to the first longer side LS1 and the second longer side LS2, the transfer speed can be improved.
Since the fourth semiconductor region SR1, which is a potential adjusting device, is shared by the area just below the portion of the photo gate electrode PG1 on the side of the first longer side LS1 and the area just below the portion of the photo gate Electrode PG1 on the side of the second longer side LS2, the use efficiency of the area is improved. Accordingly, the aperture ratio can be improved.
Since the charge transfer signals S-1 and S2 are input with mutually different phases to the plurality of Ers-th-side transfer electrodes (TX1 -i and TX2- |), and the charge transfer signals S-1 and S2 to each other discriminating phases are also input to the plurality of second-side transfer electrodes (TX12 and TX22), a noise in the collection of the signal charge is reduced, and the influence of manufacturing variations in the X-direction is reduced. Accordingly, the transfer accuracy can be improved.
Since the distance sensor P8 includes the third semiconductor regions FD3-I and FD32 and the sixth gate electrodes TX61 and TX62 on the side of the first longer side LS1 and the side of the second longer side LS2, unnecessary electric charge can be discharged , Accordingly, the transfer accuracy can be improved.
Each of the sixth gate electrodes TX61 and TX62 includes the third portion TX30 extending in the Y direction in which the first and second longer sides LS1 and LS2 extend, and the fourth portion TX40 extending from the third portion TX30 to overlap the light receiving area. When a signal charge is transferred, in areas just below the sixth gate electrodes TX6-I and TX62, the potential can be raised. Accordingly, in the light receiving area, a slope of the potential along the Y direction from the areas just below the fourth portions TX40 of the sixth gate electrodes TX61 and TX62 to the periphery thereof occurs, and the signal charge moves swiftly in the Y direction. Accordingly, the transfer speed can be improved. In particular, for a configuration that is long in the Y direction, similar to the distance sensor P8, the advantages of this embodiment are appropriately acquired.
Since the light receiving region includes the first region and the second region, and the potential adjusting device is the fourth semiconductor region SR1 having a high impurity concentration disposed between the first region and the second region, a high potential can be generated using a simple configuration.
Next, the configuration of a distance sensor according to still another embodiment will be described. Fig. 19 is a plan view illustrating a part of the distance sensor according to still another embodiment.
As illustrated in FIG. 19, a distance sensor P9 according to this embodiment differs in that it includes a sixth semiconductor region SR3, the configuration of which is different from that of the fourth semiconductor region SR1 instead of the fourth semiconductor region SR1, compared to the above described distance sensor P2 (see Fig. 12.).
A plurality of sixth semiconductor regions SR3 are arranged to be separated from each other in the Y direction between the first region on the first longer side LS1 side and the second side on the second longer side LS2 side in the light receiving region. The sixth semiconductor region SR3 shows a rectangular shape (more specifically, a rectangular shape with the X direction as its longer-side direction) in plan view. In the Y direction, between the sixth semiconductor regions SR3 and SR3, the first region and the second region of the light receiving region are connected.
Fig. 20 is a diagram showing a potential distribution on a cross section taken along a line XX-XX illustrated in Fig. 19. In the region just below the photo-gate electrode PG1, the potential of the center portion in the X direction is potential rpSR3 in the regions just below the sixth semiconductor regions SR3 and higher than the potential of the first longer side LS1 and the side rpPG1 the second longer side LS2. In addition, the potential between the sixth semiconductor regions SR3 and SR3 is higher than the first longer side LS1 side potential rpPG1 and the second longer side LS2 side due to the influence of the region potential rpSR3 just below the sixth semiconductor region SR3. Accordingly, in the area just below the photo gate electrode PG1, a high potential region extending in the Y direction is formed between the first longer side LS1 and the second longer side LS2, and a much steeper gradient of the potential, which is reduced from the area just below the sixth semiconductor region SR3 to the first longer side LS1 and the second longer side LS2.
In the distance sensor P9 according to this embodiment, since the slope of the potential is formed from the high potential region including the sixth semiconductor regions SR3 to the first longer side LS1 and the second longer side LS2, the transfer speed can be improved.
Since the sixth semiconductor region SR3, which is a potential adjusting means, is shared by the area just below the portion of the photo gate electrode PG1 on the side of the first longer side LS1 and the area just below the portion of the photo gate Electrode PG1 on the side of the second longer side LS2, the use efficiency of the area is improved. Accordingly, the aperture ratio can be improved.
Since the charge transfer signals Si and S2 having phases different from each other are input to the plurality of Ers-th side transfer electrodes (TXI-i and TX2- |), and the charge transfer signals S-1 and S2 are different from each other Also, if phases are input to the plurality of second-side transfer electrodes (TX12 and TX22), interference in signal charge collection is reduced and the influence of manufacturing variations in the X direction is reduced. Accordingly, the transfer accuracy can be improved.
Since the distance sensor P9, the third semiconductor regions FD3- | and FD32 and the third gate electrodes TX3- | and TX32 includes on the side of the first longer side LS1 and the side of the second longer side LS2, an unnecessary electric charge can be discharged. Accordingly, the transfer accuracy can be improved.
Since the light receiving region includes the first region and the second region, and the potential adjusting device is the sixth semiconductor region SR3 having a high impurity concentration disposed between the first region and the second region, a high potential can be generated using a simple configuration.
Next, the configuration of a distance sensor according to another other embodiment will be described. Fig. 21 is a plan view illustrating a part of the distance sensor according to still another embodiment. Fig. 22 is a cross-sectional view taken along a line XXII-XXII illustrated in Fig. 21;
As illustrated in FIGS. 21 and 22, a distance sensor P10 according to this embodiment differs in the configuration of a light receiving area (the configuration of openings Lla of the light shielding layer LI) and the configuration of a photo gate electrode PG1, in comparison to the above-described distance sensor P1 (see Fig. 4).
In the distance sensor P10, two openings Lla of the light shielding layer LI are arranged to be separated from each other in the X direction, so that the fourth semiconductor region SR1 is not included in the light receiving area. Each opening Lla shows a rectangular shape with the Y direction as its longer-side direction.
The light receiving area is defined by the two openings Lla on the semiconductor substrate 1A. The light receiving area corresponds to the shapes of the two openings Lla and is divided into two parts in the X direction. Each divided portion of the light receiving area shows a rectangular shape with the Y direction as its longer side direction. A portion of the light receiving area on one side (left side in Fig. 21 and Fig. 22) includes first and third longer sides LS1 and LS3, which face each other in the X direction and extend in the Y direction. A portion of the light receiving area on the other side includes second and fourth longer sides LS2 and LS4, which face each other in the X direction and extend in the Y direction. The length of each first to fourth longer side LS1 to LS4 is longer than a space between the first longer side LS1 and the second longer side LS2.
The photo gate electrode PG1 is arranged in association with the two openings Lla and is divided into two parts in the X direction. In other words, the photo gate electrode PG1 is disposed on the fourth semiconductor region SR1. Each part of the split photo gate electrode PG1 corresponds to the shape of the opening Lla and shows a rectangular shape with the Y direction as its longer side direction.
In the distance sensor P10, the fifth semiconductor region SR2 is not arranged.
Also in the distance sensor P10, similarly to the above-described distance sensor P1, the potential of the area just below the fourth semiconductor region SR1 is higher than the potential of the side of the first longer side LS1 and the side of the second longer side LS2. Accordingly, in the fourth semiconductor region SR1, a high potential region extending in the Y direction is formed between the first longer side LS1 and the second longer side LS2, and a much steeper gradient of the potential extending from the region just below the fourth semiconductor region SR1 is reduced to the first longer side LS1 and the second longer side LS2 is formed.
In the distance sensor P10 according to this embodiment, since the slope of the potential is formed from the area just below the fourth semiconductor region SR1 to the first longer side LS1 and the second longer side LS2, the transfer speed can be improved.
Since the fourth semiconductor region SR1, which is a potential adjusting means, is shared by the area just below the portion of the photo gate electrode PG1 on the side of the first longer side LS1 and the area just below the portion of the photo gate Electrode PG1 on the side of the second longer side LS2, the use efficiency of the area is improved. Accordingly, the aperture ratio can be improved.
Since the charge transfer signals S-1 and S2 having mutually different phases are input to the plurality of Ers-th-side transfer electrodes (TXI-i and TX2-i), and the charge transfer signals S1 and S2 are different from each other Also, if phases are input to the plurality of second-side transfer electrodes (TX12 and TX22), interference in signal charge collection is reduced and the influence of manufacturing variations in the X direction is reduced. Accordingly, the transfer accuracy can be improved.
Since the distance sensor P10 includes the third semiconductor regions FD3-I and FD32 and the third gate electrodes TX3-I and TX32 on the side of the first longer side LS1 and the side of the second longer side LS2, unnecessary electric charge can be generated be discharged. Accordingly, the transfer accuracy can be improved.
Since the light receiving region includes the first region and the second region, and the potential adjusting device is the fourth semiconductor region SR1 having a high impurity concentration disposed between the first region and the second region, a high potential can be generated using a simple configuration.
Next, the configuration of a distance sensor according to another another embodiment will be described. Fig. 23 is a plan view illustrating a part of the distance sensor according to still another embodiment. Fig. 24 is a cross-sectional view taken along a line XXIV-XXIV illustrated in Fig. 23;
As illustrated in FIGS. 23 and 24, a distance sensor P11 according to this embodiment differs in the configuration of a potential adjusting device as compared with the above-described distance sensor P1 (see FIG. 4). More specifically, the distance sensor P11 is different from the distance sensor P1 in that the configuration of the photo gate electrode PG1 is different, a potential adjusting electrode PG2 is further included, and the fourth semiconductor region SR1 is not disposed.
In the distance sensor P10, the photo gate electrode PG1 is divided into two parts in the X direction. Each part of the split photo gate electrode PG1 shows a rectangular shape with the Y direction as its longer side direction. The part of the split photo gate electrode PG1 on the side of the first longer side LS1 serves as a first electrode part. The part of the split photo gate electrode PG1 on the side of the second longer side LS2 serves as a second electrode part.
The potential adjusting electrode PG2 is disposed on the light incident surface 1FT through the insulating layer 1E. The potential adjusting electrode PG2 is disposed between the first electrode portion and the second electrode portion of the photo gate electrode PG1 to be separate therefrom. In other words, the potential adjusting electrode PG2 is electrically disconnected from the first electrode part and the second electrode part of the photo gate electrode PG1. The potential adjusting electrode PG2 shows a rectangular shape with the Y direction as its longer-side direction in plan view. The potential insertion electrode PG2 may be formed using polysilicon or any other material.
An electric potential lower than that applied to the photo gate electrode PG1 is applied to the potential adjusting electrode PG2. Accordingly, the potential of the region just under the potential adjusting electrode PG2 is higher than that of the first longer side LS1 side and the second longer side LS2 side (the potential of the regions just below the photo gate electrode PG1). In the area just below the potential adjusting electrode PG2 between the first longer side LS1 and the second longer side LS2, accordingly, a high potential region extending in the Y direction is formed, and a much steeper gradient of the potential arising from the region just below the potential adjusting electrode PG2 decreases to the first longer side LS1 and the second longer side LS2.
In the distance sensor P10, the fifth semiconductor region SR2 is not arranged.
In the distance sensor P11 according to this embodiment, since the slope of the potential is formed from the area just below the potential adjusting electrode PG2 to the first longer side LS1 and the second longer side LS2, the transfer speed can be improved.
Since the potential adjusting electrode PG2, which is a potential adjusting means, is shared by the area just below the portion of the photo gate electrode PG1 on the side of the first longer side LS1 and the area just below the portion of the photo gate PG1 electrode on the side of the second longer side LS2, the use efficiency of the area is improved. Accordingly, the aperture ratio can be improved.
Since the charge transfer signals S-ι and S2 are input to the plurality of first-side transfer electrodes (TXI-i and TX2- |) having phases different from each other, and the charge transfer signals S-ι and S2 are applied to each other also input to the plurality of second-side transfer electrodes (TX12 and TX22), interference in the collection of the signal charge decreases, and the influence of manufacturing variations in the X-direction is reduced. Accordingly, the transfer accuracy can be improved.
Since the distance sensor P11 includes the third semiconductor regions FD3-I and FD32 and the third gate electrodes TX3-i and TX32 on the side of the first longer side LS1 and the side of the second longer side LS2, unnecessary electric charge can be generated be discharged. Accordingly, the transfer accuracy can be improved.
The photo gate electrode PG1 includes the first electrode portion disposed on the side area of the first longer side LS1 of the light receiving area and the second electrode portion separated from the first electrode portion in the X direction in which the first longer side LS1 and the second longer LS2 face each other, and is disposed on the side area of the second longer side of the light receiving area. The potential adjusting means is the potential adjusting electrode PG2 disposed between the first electrode part and the second electrode part to be electrically separated from the first and second electrode parts, and becomes lower in electrical potential than an electric potential applied to the photo gate electrode provided. That's why

权利要求:
Claims (10)
[1]
by adjusting the electric potential applied to the photo-gate electrode PG1 and the potential adjusting electrode PG2, the degree of the slope of the potential is appropriately set. As described above, while the preferred embodiments of the present invention have been described, the present invention is not necessarily limited to the above-described embodiments, and various changes can be made therein in a range that does not depart from its spirit. The distance image sensor 1 is not limited to the distance image sensor of the front-lit type. The distance image sensor 1 may be a backlit type distance image sensor. In addition, the electric-charge generating region in which an electric charge is generated in accordance with the incident light may be configured by a photo-diode (for example, a pinned photodiode). The distance image sensor 1 is not limited to a distance image sensor in which the distance sensors P1 to 10 are arranged in a one-dimensional pattern, but may be a distance image sensor in which the distance sensors P1 to 10 are arranged in a two-dimensional pattern. In the distance image sensor 1 according to this embodiment, the conductivity types of the p-type and the n-type can be exchanged to be types opposite to those described above. Industrial Applicability The present invention can be used, for example, for a distance sensor, a distance image sensor, and the like installed in a product monitor in a production line of a factory, a vehicle, or the like. [0183] 1 Distance image sensor FD1-I to FD32 First to third semiconductor regions LS1 First longer side of light receiving area LS2 Second longer side of light receiving area P1 to P10 Distance sensor PG1 Photo gate electrode PG2 Potential setting electrode SR1 Fourth semiconductor region SR3 Sixth semiconductor region TX1-I to TX62 First to sixth gate electrodes Claims 1. A distance sensor (P1) comprising: a rectangular light receiving area having a first side edge (LS1) and a second side edge (LS2) facing each other, the length of the first and second side edges (LS1, LS2) is longer than a gap between the first side edge (LS1) and the second side edge (LS2); a photo gate electrode (PG1) disposed along the first side edge (LS1) and the second side edge (LS2) in the light receiving area; a plurality of first-side signal charge collection regions (FD11, FD2-i) disposed adjacent the first side edge (LS1) of the light receiving region so as to be spaced apart along the first side edge, and one corresponding to the incident one Collect light generated signal charge; a plurality of second-side signal charge-collecting regions (FD12, FD22) disposed adjacent to the second side edge (LS2) of the light-receiving area so as to be spaced apart along the second side edge (LS2), each of the plurality of second Side signal charge collection regions (FD2-I, FD22) is arranged to face the corresponding first side signal charge collection region (FD1 -i, FD2-i) on the other side of the light receiving region, and collects another signal charge ; a plurality of first-side transfer electrodes (TX1i, TX2- |) adapted to be charged with charge transfer signals having phases different from each other and connected between the respective first-side signal charge collection regions (FD1-i, FD2- i) and the photo gate electrode (PG1) are arranged along the first side edge (LS1); a plurality of second-side transfer electrodes (TX12, TX22) adapted to be supplied with the charge transfer signals having phases different from each other and between the corresponding second-side signal charge collection regions (FD12, FD22) and the photograph Gate electrode (PG1) are arranged along the second side edge (LS2); and a potential adjusting device (SR1) positioned between the first side edge (LS1) and the second side edge (LS2), and capable of detecting the potential of an area corresponding to the light receiving area and extending in a direction in which the first and second regions second side edges (LS1, LS2) extend to be higher than a potential of an area located adjacent to the first side edge (LS1) along the first side edge (LS1), and to be higher than a potential of a region is arranged adjacent to the second side edge (LS2) along the second side edge (LS2), so that an inclination of the potential is formed from the area with the raised potential to the area adjacent to the first side edge (LS1) and the area adjacent to the second side edge (LS2). LS2).
[2]
The distance sensor according to claim 1, wherein the plurality of first-side transfer electrodes (TX1-i, TX2- |) and the plurality of second-side transfer electrodes (TX2-I, TX22) are arranged such that the first side The transfer electrode and the second-side transfer electrode, which are adapted to be charged with the charge transfer signals of the same phase, face each other in a direction in which the first side edge (LS1) and the second side edge (LS2) face each other.
[3]
The distance sensor according to claim 1, wherein the plurality of first-side transfer electrodes (TX1-i, TX2- |) and the plurality of second-side transfer electrodes (TX2-I, TX22) are arranged such that the first side Transfer electrode and the second-side transfer electrode, which are adapted to be charged with the charge transfer signals having phases different from each other, face each other in a direction in which the first side edge (LS1) and the second side edge (LS2) face each other are opposite.
[4]
4. The distance sensor according to claim 1, wherein the plurality of first-side transfer electrodes (TX1i, TX2-i) and the plurality of second-side transfer electrodes (TX2-I, TX22) are arranged at positions deviated from each other in the direction in which the first and second side edges (LS1, LS2) extend.
[5]
A distance sensor according to any one of claims 1 to 4, wherein said plurality of first-side transfer electrodes (TX1i, TX2-i) includes a pair of said first-side transfer electrodes (TX4-I, TX5i) which are suitable with Charge transfer signals to be acted upon with mutually different phases, and adjacent to each other in the direction in which the first and second side edges (LS1, LS2) extend, wherein the plurality of second-side transfer electrodes (TX2-I, TX22) a A pair of the second-side transfer electrodes (TX42, TX52), which are adapted to be charged with the charge transfer signals having phases different from each other, and adjacent to each other in the direction in which the first and second side edges (LS1, LS2 ), and wherein each of the first-side transfer electrodes of the pair (TX4-I, TX5i) and each of the second-side transfer electrodes of the pair (TX42, TX52) includes a first portion (TX10) which is si ch in the direction in which the first and second side edges (LS1, LS2) extend, and a second portion (TX20) extending perpendicular to the direction in which the first portion (TX10) extends and Light receiving area of the end portion of the first portion (TX10) overlaps, wherein the end portion is positioned more distant from the adjacent first portion (TX10) of the other transfer electrode of a pair.
[6]
The distance sensor according to any one of claims 1 to 5, further comprising: first-side surplus electric charge discharge regions (FD3-i) disposed adjacent to the first side edge (LS1) of the light receiving region so as to be along the first side edge (LS2) are spaced from each other and separate from the first-side signal charge collection regions and covered with a light-shielding layer (LI) and capable of discharging a generated excess electric charge; Second-side surplus electric charge discharge regions (FD32) disposed adjacent to the second side edge (LS2) of the light receiving area so as to be spaced apart along the second side edge (LS2) and from the second side signal charge. Collection regions are separated, and which are covered with a light shielding layer (LI) and are adapted to discharge a generated excess electric charge; First-side excess electric charge discharge gate electrodes (TX3i) disposed between the first-side surplus electric charge discharge regions (FD3-i) and the photo gate electrode are selectively arranged blocking and releasing a flow of excess electric charge to the first side excess electrical charge discharge regions (FD3-i); and second-side surplus electric charge discharge gate electrodes (TX32) interposed between the second-side excess electric charge discharge regions (FD32) and the photo-gate electrode to selectively block and release a flow of excess electrical charge to the second-side-over-electrical-charge-discharge regions (FD32).
[7]
A distance sensor according to claim 6, wherein each of said first-side surplus electric charge discharge Ga-th electrodes (TX3i) and said second-side surplus electric charge discharge gate electrodes (TX32) a third portion (TX30) extending in the direction in which the first and second side edges (LS1, LS2) extend, and a fourth portion (TX40) extending perpendicularly from the third portion in the direction, in which the third section extends to overlap the light receiving area,
[8]
A distance sensor according to any one of claims 1 to 7, wherein said light receiving area includes a first area (SR2- |) including said first side edge (LS1) and extending in a direction in which said first side edge (LS1) extends, and a second region (SR22) including the second side edge (LS2) and extending in a direction in which the second side edge (LS2) extends, and wherein the potential adjusting device (SR1) is a semiconductor region extending between the first region (SR2-i) and the second region (SR22), and has the same conductivity type as the first and second regions, and has a higher impurity concentration than those of the first and second regions.
[9]
A distance sensor according to any one of claims 1 to 7, wherein said photo gate electrode (PG1) includes a first electrode portion disposed on a side area of said first side edge (LS1) of said light receiving area and a second electrode portion spaced from said first electrode portion Electrode part is separated in a direction perpendicular to the direction in which the first region extends, and in which the first side edge (LS1) and the second side edge (LS2) are opposed to each other, and on a side region of the second side edge (LS2) the potential-adjusting device (PG2) is an electrode disposed between the first electrode part and the second electrode part to be electrically separated from the first and second electrode parts, and arranged to be lower in electrical potential as an electric potential applied to the photo gate electrode (PG1).
[10]
A distance image sensor (1) having an image sensing area configured by a plurality of units arranged in a one-dimensional pattern or a two-dimensional pattern on a semiconductor substrate and capable of acquiring a distance image based on amounts of electric charges output from the units Acquire, wherein each of the units is a distance sensor (P1) according to one of claims 1 to 9.

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EP3663806A1|2020-06-10|Photon detector, method for producing a photon detector and x-ray device

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JP2012083222A|2012-04-26|Distance sensor and distance image sensor

同族专利:

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公开号 | 公开日

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US20150276922A1|2015-10-01|

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KR102033812B1|2019-10-17|

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KR20150079545A|2015-07-08|

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JP6010425B2|2016-10-19|

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WO2014064973A1|2014-05-01|

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JP2014085314A|2014-05-12|

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US9664780B2|2017-05-30|

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DE112013005141T5|2015-08-06|

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法律状态:

优先权:

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申请号 | 申请日 | 专利标题

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JP2012236914A|JP6010425B2|2012-10-26|2012-10-26|Distance sensor and distance image sensor|

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PCT/JP2013/068525|WO2014064973A1|2012-10-26|2013-07-05|Distance sensor and distance image sensor|

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