Solid-state imaging device

Abstract

[Problem] To provide a solid-state imaging device capable of improving captured image quality. [Solution] The solid-state imaging device comprises: a first semiconductor layer of a first conductivity type which performs photoelectric conversion; a second semiconductor layer of the first conductivity type which is disposed on the opposite side to a light entrance surface of the first semiconductor layer, includes a material having a greater bandgap than the first semiconductor layer, and performs photoelectric conversion; a diffusion layer of a second conductivity type disposed extending from the opposite side to the interface between the second semiconductor layer and the first semiconductor layer, through the second semiconductor layer, to the inside of the first semiconductor layer; an electrode connected to the diffusion layer on the opposite side to the interface between the second semiconductor layer and the first semiconductor layer; and a pixel separation part disposed in the depth direction of the first semiconductor layer and the second semiconductor layer along a plurality of pixel regions partitioning the first semiconductor layer and the second semiconductor layer, wherein a plurality of diffusion layers are disposed in each of the plurality of pixel regions.

Description

solid-state imaging device

[0001] The present disclosure relates to a solid-state imaging device.

[0002] A solid-state imaging device having sensitivity in the infrared region uses a photoelectric conversion layer containing a compound semiconductor material such as InGaAs (indium gallium arsenide) or InP (indium phosphide) (see Patent Document 1).

[0003] International Publication No. 2019 / 211968

[0004] A solid-state imaging device having sensitivity in the infrared region generally does not include a pixel separating section, and therefore has a problem in that crosstalk, in which charges generated by photoelectric conversion flow into adjacent pixels, is likely to occur.

[0005] When a pixel separating portion is formed in the pixel boundary region of the photoelectric conversion layer, damage during processing may cause defects in the photoelectric conversion layer, which may increase dark current.

[0006] A diffusion layer is disposed in part of the photoelectric conversion layer to read out the charges generated by photoelectric conversion. If the size of the diffusion layer is small, the charges generated by photoelectric conversion near the pixel boundaries will recombine due to the defects mentioned above, resulting in a decrease in quantum efficiency.

[0007] Conversely, if the size of the diffusion layer is increased, the capacitance of the PN junction formed at the interface of the diffusion layer increases, resulting in a decrease in readout speed and a dark current due to a depletion layer formed near the PN junction, degrading the image quality.

[0008] Therefore, the present disclosure provides a solid-state imaging device capable of improving image quality.

[0009] In order to solve the above-described problems, according to the present disclosure, there is provided a solid-state imaging device comprising: a first semiconductor layer of a first conductivity type that performs photoelectric conversion; a second semiconductor layer of the first conductivity type that is arranged on a surface opposite to a light incident surface of the first semiconductor layer, contains a material having a larger band gap than the first semiconductor layer, and performs photoelectric conversion; a diffusion layer of a second conductivity type that is arranged from a surface of the second semiconductor layer opposite to an interface with the first semiconductor layer, penetrating the second semiconductor layer to an interior of the first semiconductor layer; an electrode connected to the diffusion layer on a surface of the second semiconductor layer opposite to the interface with the first semiconductor layer; and a pixel separation portion that is arranged in a depth direction of the first semiconductor layer and the second semiconductor layer along a plurality of pixel regions that divide the first semiconductor layer and the second semiconductor layer, and a plurality of the diffusion layers are arranged in each of the plurality of pixel regions.

[0010] Each of the plurality of pixel regions may have a rectangular shape having a short side and a long side that is longer than the short side when viewed in a plane, and the plurality of diffusion layers included in one pixel region may be arranged spaced apart from each other along the long side of the pixel region when viewed in a plane.

[0011] a first semiconductor layer of a first conductivity type that performs photoelectric conversion; a second semiconductor layer of the first conductivity type that is arranged on a surface opposite to a light incident surface of the first semiconductor layer, contains a material having a larger band gap than the first semiconductor layer, and performs photoelectric conversion; a diffusion layer of a second conductivity type that is arranged from a surface of the second semiconductor layer opposite to an interface with the first semiconductor layer, penetrating the second semiconductor layer to an interior of the first semiconductor layer; and an electrode connected to the diffusion layer on a surface of the second semiconductor layer opposite to the interface with the first semiconductor layer, wherein each of a plurality of pixel regions that partition the first semiconductor layer and the second semiconductor layer has a rectangular shape having short sides and long sides that are longer than the short sides when viewed in a plan view, and a plurality of the diffusion layers may be arranged in each of the plurality of pixel regions along the long sides.

[0012] The semiconductor device may further include a pixel separating portion disposed in a depth direction of the first semiconductor layer and the second semiconductor layer along a boundary between the plurality of pixel regions.

[0013] The plurality of diffusion layers may be arranged along the center of the short side of each of the plurality of pixel regions, spaced apart in the direction of the long side.

[0014] The pixel separating portion may be arranged along the long side of each of the plurality of pixel regions.

[0015] The first semiconductor layer and the second semiconductor layer may be III-V compound semiconductor layers.

[0016] Each of the plurality of diffusion layers may be a diffusion layer containing impurity ions of a second conductivity type, and the second semiconductor layer may be disposed between two adjacent diffusion layers and have a non-diffusion layer that does not contain the impurity ions of the second conductivity type.

[0017] The electrode may be provided for each of the plurality of pixel regions and connected to the plurality of diffusion layers in the corresponding pixel region.

[0018] The electrodes may be provided separately for each of the plurality of diffusion layers in the corresponding pixel region and connected to the corresponding diffusion layer.

[0019] The light emitting device may further include a conductive member connected to the plurality of electrodes and arranged opposite the plurality of diffusion layers with the plurality of electrodes sandwiched therebetween.

[0020] 1. A solid-state imaging device comprising: a photoelectric conversion layer including a compound semiconductor material; and a plurality of light-shielding members each spaced apart on a light incident surface side of the photoelectric conversion layer; wherein the photoelectric conversion layer is divided into a plurality of pixel regions each arranged in a first direction and a second direction intersecting each other; wherein, of the plurality of pixel regions, two pixel regions arranged adjacent to each other in the first direction are covered with the light-shielding member, and the other pixel region is not covered with the light-shielding member; and wherein, of the plurality of pixel regions, two pixel regions arranged adjacent to each other in the second direction are covered with the light-shielding member, and the other pixel region is not covered with the light-shielding member.

[0021] The photoelectric conversion layer may have: a first semiconductor layer of a first conductivity type that performs photoelectric conversion; a second semiconductor layer of the first conductivity type that is arranged on the surface opposite to the light incident surface of the first semiconductor layer, contains a material having a larger band gap than the photoelectric conversion layer, and performs photoelectric conversion; and a diffusion layer of a second conductivity type that is arranged from the surface of the second semiconductor layer opposite to the interface with the first semiconductor layer, through the second semiconductor layer, to the inside of the first semiconductor layer, and the multiple light-shielding members may be arranged spaced apart from each other on the light incident surface side of the first semiconductor layer.

[0022] The pixel array may include a first pixel group including two or more of the pixel regions arranged along the first direction; and a second pixel group arranged adjacent to the first pixel group in the second direction and including two or more of the pixel regions arranged along the first direction, wherein all pixel regions in the first pixel group that are not covered by the light-shielding member and all pixel regions in the second pixel group that are not covered by the light-shielding member may be arranged offset from each other in the first direction.

[0023] Two or more pixel group regions each including the first pixel group and the second pixel group that are arranged adjacent to each other in the second direction may be arranged along the second direction.

[0024] The pixel array may include a third pixel group arranged between two pixel group regions arranged adjacent to each other in the second direction, and in which all of two or more pixel regions arranged along the first direction are covered by the light-shielding member.

[0025] The pixel array comprises: a first pixel group including two or more pixel regions arranged along the first direction; a second pixel group arranged apart from the first pixel group in the second direction and including two or more pixel regions arranged along the first direction; and a third pixel group arranged between the first pixel group and the second pixel group in the second direction, in which all of the two or more pixel regions arranged along the first direction are covered with the light-shielding member, wherein all pixel regions in the first pixel group that are not covered with the light-shielding member and all pixel regions in the second pixel group that are not covered with the light-shielding member may be arranged offset from each other in the first direction.

[0026] The pixel group may include a plurality of pixel group regions arranged in the second direction in the order of the first pixel group, the third pixel group, and the second pixel group, and the third pixel group may be arranged between two of the pixel group regions arranged adjacent to each other in the second direction.

[0027] The display device may include a plurality of pixel groups that are arranged along the second direction and each of the pixel groups includes two or more of the pixel regions that are arranged along the first direction, and the pixel regions that are not covered by the light-shielding member in each of the plurality of pixel groups may be arranged so as to be shifted from one another in the first direction.

[0028] The light blocking member may be a light reflecting layer that reflects incident light or a light absorbing layer that absorbs incident light.

[0029] 11. A block diagram showing an outline of an imaging device according to the present disclosure. A schematic diagram showing a layered structure of a solid-state imaging device 1 according to the present disclosure. A plan view of a solid-state imaging device 1 according to a first embodiment of the present disclosure. A cross-sectional view taken along line A-A' in FIG. 3. A cross-sectional view taken along line B-B' in FIG. 3. A plan view of a solid-state imaging device according to a first comparative example. A cross-sectional view taken along line A-A' in FIG. 5. A plan view of a solid-state imaging device according to a second comparative example. A cross-sectional view taken along line A-A' in FIG. 7. A plan view of a solid-state imaging device according to a first modified example of the first embodiment. A cross-sectional view taken along line A-A' in FIG. 9. A cross-sectional view taken along line B-B in FIG. 9. A plan view of a solid-state imaging device according to a second modified example of the first embodiment. A cross-sectional view taken along line A-A' in FIG. 11. A plan view of a solid-state imaging device according to a third modified example of the first embodiment. A cross-sectional view taken along line A-A' in FIG. 13. A plan view of a solid-state imaging device according to a second embodiment. A plan view of a solid-state imaging device according to a comparative example. A cross-sectional view when the light-shielding member is a light-reflecting layer. FIG. 1 is a cross-sectional view in a case where the light-shielding member is a light-absorbing layer. FIG. 2 is a plan view of a solid-state imaging device according to a first modified example of the second embodiment. FIG. 3 is a plan view of a solid-state imaging device according to a second modified example of the second embodiment. FIG. 4 is a plan view of a solid-state imaging device according to a fourth modified example of the second embodiment. FIG. 5 is a plan view of a solid-state imaging device according to a fifth modified example of the second embodiment. FIG. 6 is a block diagram showing an example of the schematic configuration of a vehicle control system. FIG. 7 is an explanatory diagram showing an example of the installation positions of an outside vehicle information detection unit and an imaging unit.

[0030] Hereinafter, an embodiment of a solid-state imaging device will be described with reference to the drawings. The following description will focus on the main components of the solid-state imaging device, but the solid-state imaging device may include components and functions that are not shown or described. The following description does not exclude components and functions that are not shown or described.

[0031] (Overview of Imaging Device) Fig. 1 is a block diagram showing an overview of a solid-state imaging device 1 according to the present disclosure. The solid-state imaging device 1 according to the present disclosure captures images of light in the infrared band, for example. The solid-state imaging device 1 according to the present disclosure includes a pixel region 2 and a circuit unit 3. The circuit unit 3 includes a row scanning unit 31, a horizontal selection unit 32, a column scanning unit 33, and a system control unit 34.

[0032] The pixel region 2 has a configuration in which a plurality of pixels 20 are two-dimensionally arranged in a matrix. Here, the column direction refers to the direction in which a plurality of pixel drive lines 35 are arranged and the direction in which each signal line 36 extends. The row direction (also referred to as the first direction) refers to the direction in which a plurality of signal lines 36 are arranged and the direction in which each pixel drive line 35 extends. In this specification, a row of pixels 20 arranged in the row direction is referred to as a pixel row, and a column of pixels 20 arranged in the column direction (also referred to as the second direction) is referred to as a pixel column. In the pixel region 2, a pixel drive line 35 is arranged for each pixel row. One end of the pixel drive line 35 is connected to an output terminal of the row scanning unit 31 corresponding to each row. In addition, a signal line 36 is arranged for each pixel column. Each signal line 36 transmits pixel signals output from each pixel 20 in the corresponding pixel column.

[0033] Although not shown, the row scanning unit 31 and the column scanning unit 33 each include a shift register, an address decoder, and the like. The horizontal selection unit 32 also includes an amplifier, a horizontal selection switch, and the like. As described above, the row scanning unit 31 is connected to a plurality of pixel drive lines 35. The row scanning unit 31 sequentially drives the plurality of pixel drive lines 35 to sequentially select corresponding pixel rows in the pixel region 2. Each pixel 20 in the selected pixel row supplies a pixel signal to the horizontal selection unit 32 via a corresponding signal line 36. The column scanning unit 33 controls the selection of the signal line by the horizontal selection unit 32. Under the control of the column scanning unit 33, the horizontal selection unit 32 sequentially selects pixel signals on the plurality of signal lines and supplies them to a signal processing unit (not shown) or the like via a signal line 37 extending in the horizontal direction.

[0034] The system control unit 34 receives an externally applied clock and synchronously controls the row scanning unit 31, the horizontal selection unit 32, and the column scanning unit 33. It also receives data instructing an operation mode and outputs data such as internal information of the solid-state imaging device 1.

[0035] FIG. 2 is a schematic diagram showing the stacked structure of a solid-state imaging device 1 according to the present disclosure. The solid-state imaging device 1 according to the present disclosure can be configured, for example, with a stacked structure of semiconductor chips. The solid-state imaging device 1 of FIG. 2 is configured by stacking a pixel chip 11 on which a pixel region 2 is arranged and a circuit chip 12 on which a pixel circuit, a circuit unit 3, and the like are arranged. These chips are connected by Cu-Cu bonding or the like to transmit various signals. Note that the pixel chip 11 and the circuit chip 12 may be connected by vias, bumps, or the like in addition to Cu-Cu bonding. However, the solid-state imaging device 1 is not limited to the stacked structure shown in FIG. 2. For example, the solid-state imaging device 1 may be configured by stacking three or more chips, or may have a flat-type chip structure in which the pixel region 2 and the circuit unit 3 are arranged on the same chip.

[0036] First Embodiment FIG. 3 is a plan view of a solid-state imaging device 1 according to a first embodiment of the present disclosure, FIG. 4A is a cross-sectional view taken along line AA' in FIG. 3, and FIG. 4B is a cross-sectional view taken along line BB' in FIG.

[0037] 3, the solid-state imaging device 1 according to the first embodiment includes a rectangular pixel region 21 and pixel separation sections 22. Each pixel separation section 22 is disposed in a pixel boundary region in a first direction (horizontal direction) X, and extends in a second direction (vertical direction) Y along the pixel boundary region.

[0038] The dashed lines in Figure 3 indicate a single pixel region 21. Figure 3 shows an example in which the pixel region 21 has a rectangular shape in plan view, with a short side in the first direction X and a long side in the second direction Y that is longer than the short side. The ratio of the lengths of the short side and the long side of the pixel region 21 is arbitrary. A plurality of openings 23 are arranged in the pixel region 21. As will be described later, these openings 23 are used to connect the diffusion layer and the p-type electrode. In plan view, the openings 23 are covered with an electrode, but the electrode is not shown in Figure 3. The periphery of the plurality of openings 23 is covered with an insulating layer 24. The insulating layer 24 is made of, for example, SiO2 or SiN.

[0039] 3 shows an example in which four openings 23 are provided in a single pixel region 21, but the number of openings 23 may vary depending on the lengths of the pixel region 21 in the first direction X and the second direction Y. However, providing a plurality of openings 23 in a single pixel region 21 is one of the technical features of the solid-state imaging device 1 according to the first embodiment.

[0040] 4A and 4B , the solid-state imaging device 1 according to the first embodiment has a stacked structure in which a second semiconductor layer 26 is disposed on a first semiconductor layer 25. Both the first semiconductor layer 25 and the second semiconductor layer 26 are semiconductor layers whose base material is, for example, a III-V group compound semiconductor material, and are capable of photoelectric conversion. In this specification, the first semiconductor layer 25 and the second semiconductor layer 26 may be collectively referred to as a photoelectric conversion layer.

[0041] The first semiconductor layer 25 and the second semiconductor layer 26 are divided into a plurality of pixel regions 21. A pixel separating section 22 is arranged in the depth direction of the first semiconductor layer 25 and the second semiconductor layer 26 along the boundary region between the plurality of pixel regions 21. As shown in FIG. 3 , the pixel separating section 22 is arranged, for example, along the long side of each of the plurality of pixel regions 21.

[0042] The second semiconductor layer 26 is made of a material having a larger energy gap than the first semiconductor layer 25. The first semiconductor layer 25 is made of, for example, InGaAs as a base material, and the second semiconductor layer 26 is made of, for example, InGaP as a base material. The first semiconductor layer 25 and the second semiconductor layer 26 contain impurity ions of a first conductivity type (for example, n-type). The n-type impurity concentration of the second semiconductor layer 26 is higher than the n-type impurity concentration of the first semiconductor layer 25.

[0043] The light incident surface is the surface of the first semiconductor layer 25 opposite to the interface with the second semiconductor layer 26. A transparent electrode layer or the like is disposed on the light incident surface of the first semiconductor layer 25, but is not shown in FIGS.

[0044] A plurality of diffusion layers 27 are arranged on the surface of the second semiconductor layer 26 opposite to the interface with the first semiconductor layer 25. These diffusion layers 27 are arranged to penetrate the second semiconductor layer 26 and into the first semiconductor layer 25. The conductivity type (second conductivity type) of these diffusion layers 27 is opposite to the conductivity type (first conductivity type) of the first semiconductor layer 25 and the second semiconductor layer 26. The first semiconductor layer 25 and the second semiconductor layer 26 are, for example, n-type (first conductivity type), whereas the plurality of diffusion layers 27 are, for example, p-type (second conductivity type).

[0045] The multiple diffusion layers 27 are arranged spaced apart from one another in the second direction Y along the center of the short side of the pixel region 21. For example, the multiple diffusion layers 27 are arranged at regular intervals in the second direction Y. The size of the diffusion layers 27 is arbitrary, but the larger the size of the diffusion layers 27 in the planar direction, the larger the capacitance of the PN junctions formed at the interfaces between the diffusion layers 27 and the first and second semiconductor layers 26. The larger the capacitance of the PN junctions, the slower the readout speed of charges generated by photoelectric conversion and the larger the dark current. Therefore, the size of the diffusion layers 27 is determined taking these factors into consideration.

[0046] The second semiconductor layer 26 has a diffusion layer 27 containing p-type impurities and a non-diffusion layer 28 not containing p-type impurities. That is, the non-diffusion layer 28 is disposed between two diffusion layers 27 adjacent to each other in the surface direction.

[0047] 4B , the pixel separating portion 22 between two pixel regions 21 adjacent to each other in the first direction X is disposed so as to separate at least a part of the first semiconductor layer 25 and the second semiconductor layer 26. The pixel separating portion 22 is formed by depositing a layer of, for example, SiO 2 inside a trench formed along the pixel boundary region. ２ Alternatively, the trench may be filled with an insulating material such as SiN. Alternatively, the trench may be filled with a metal material such as aluminum (Al). By providing the pixel separation portion 22, it is possible to prevent charges generated by photoelectric conversion in the pixel region 21 from flowing into an adjacent pixel region 21, thereby suppressing the occurrence of crosstalk.

[0048] An insulating layer 24 is disposed on the surface of the second semiconductor layer 26 opposite the interface with the first semiconductor layer 25, and as shown in Fig. 3, a plurality of openings 23 are provided in the insulating layer 24 to correspond to the locations of the plurality of diffusion layers 27. Electrodes (not shown) are connected to the plurality of diffusion layers 27 via these openings 23. Charges (e.g., holes) generated by photoelectric conversion in the first semiconductor layer 25 and the second semiconductor layer 26 are collected in the electrodes via the plurality of diffusion layers 27.

[0049] In the process of forming the pixel separation portion 22, defects may occur in the first semiconductor layer 25 and the second semiconductor layer 26, which may cause dark current to occur near the defective portion. Charges generated by photoelectric conversion near the defective portion are likely to recombine with charges due to dark current, resulting in a decrease in quantum efficiency.

[0050] In this embodiment, multiple diffusion layers 27 are arranged along the long side direction within a single pixel region 21. This makes it easier for the charges generated by photoelectric conversion near the pixel separating portion 22 to be collected by the nearest diffusion layer 27, reducing the probability of recombination due to dark current and suppressing a decrease in quantum efficiency.

[0051] Fig. 5 is a plan view of a solid-state imaging device 100 according to a first comparative example, and Fig. 6 is a cross-sectional view taken along line A-A' in Fig. 5. The solid-state imaging device 100 according to the first comparative example includes a rectangular pixel region 21, similar to the solid-state imaging device 1 according to the first embodiment. The pixel region 21 according to the first comparative example has a rectangular opening 23 extending in its longitudinal direction. The opening 23 has a size and shape similar to the outer shape of the pixel region 21.

[0052] In the solid-state imaging device 100 according to the first comparative example, as shown in FIG. 6, the diffusion layer 27 is disposed over most of the second semiconductor layer 26, and the size of the non-diffusion layer 28 is extremely small compared to the diffusion layer 27.

[0053] In the first comparative example, the capacitance due to the PN junction formed at the interface between the diffusion layer 27 and the first and second semiconductor layers 25 and 26 (hereinafter referred to as the PN junction capacitance) increases, the readout speed of the charge generated by photoelectric conversion decreases, and the dark current due to the depletion layer formed near the PN junction surface increases, resulting in a decrease in quantum efficiency.

[0054] Fig. 7 is a plan view of a solid-state imaging device 100a according to a second comparative example, and Fig. 8 is a cross-sectional view taken along line A-A' in Fig. 7. The solid-state imaging device 100a according to the second comparative example has a rectangular pixel region 21, similar to the solid-state imaging device 1 according to the first embodiment. The pixel region 21 according to the second comparative example has only one opening 23 of approximately the same size as the opening 23 in the pixel region 21 according to the first embodiment.

[0055] 8, in the solid-state imaging device 100a according to the second comparative example, the diffusion layer 27 in the second semiconductor layer 26 is extremely smaller than the size of the non-diffusion layer 28. As a result, the distance over which the charges generated by photoelectric conversion near the four corners of the pixel region 21 are transferred to the diffusion layer 27 becomes longer, making it easier for the charges to recombine with charges due to dark current generated by defects near the pixel separating portion 22, resulting in a decrease in quantum efficiency.

[0056] Compared to the first and second comparative examples, the solid-state imaging device 1 according to the first embodiment has a plurality of diffusion layers 27 provided within a single pixel region 21, which makes it easier to collect charges generated by photoelectric conversion near the pixel separating section 22 via the nearest diffusion layer 27. Providing a plurality of diffusion layers 27 makes it less likely for recombination to occur with charges due to dark current generated by defects near the pixel separating section 22, thereby suppressing a decrease in quantum efficiency.

[0057] 3, 4A, and 4B show examples in which the pixel separating section 22 is provided, but it is also possible to consider an example in which the pixel separating section 22 is not provided. Fig. 9 is a plan view of a solid-state imaging device 1a according to a first modified example of the first embodiment, Fig. 10A is a cross-sectional view taken along line A-A' in Fig. 9, and Fig. 10B is a cross-sectional view taken along line B-B in Fig. 9.

[0058] 9, 10A, and 10B differ from those of FIGS. 3, 4A, and 4B in that the solid-state imaging device 1a according to the first modification does not have a pixel separating portion 22 in the pixel boundary region. The cross-sectional view taken along line A-A in FIG. 10A is the same as that in FIG. 4A.

[0059] The solid-state imaging device 1a according to the first modification does not have pixel separation portions 22, and therefore is less likely to have defects near pixel boundary regions, making it less likely for charge recombination with dark current due to defects to occur, but on the other hand, there is a risk that charges generated by photoelectric conversion near pixel boundary regions may flow into adjacent pixel regions 21. In the first modification, multiple diffusion layers 27 are disposed inside pixel regions 21, which makes it easier to transfer charges generated by photoelectric conversion near pixel boundary regions to the nearest diffusion layers 27, and makes it possible to suppress crosstalk, in which charges flow into adjacent pixel regions 21.

[0060] As described above, the plurality of diffusion layers 27 in the pixel region 21 are connected to the electrodes via the plurality of openings 23. Various modifications are possible for the arrangement of the electrodes.

[0061] Fig. 11 is a plan view of a solid-state imaging device 1b according to a second modified example of the first embodiment, and Fig. 12 is a cross-sectional view taken along line A-A' in Fig. 11. The second modified example has a structure in which an electrode 41 is added to the pixel region 21 according to the first embodiment shown in Figs. 3, 4A, and 4B.

[0062] The electrode 41 according to the second modification is provided for each pixel region 21 and is connected to the plurality of diffusion layers 27 via the plurality of openings 23 in the pixel region 21. That is, in the second modification, a single electrode 41 is provided for each pixel region 21, and all of the diffusion layers 27 in the pixel region 21 are connected to this electrode 41. An insulating layer 24 is disposed on the surface of the second semiconductor layer 26 opposite the interface with the first semiconductor layer 25, and the electrode 41 is disposed so as to cover the top surface of the insulating layer 24 and the side and bottom surfaces of the openings 23. Therefore, the cross-sectional structure of the electrode 41 in the long side direction of the pixel region 21 has an uneven structure as shown in FIG.

[0063] The electrode 41 functions as a p-type electrode 41 and collects holes generated by photoelectric conversion via the electrode 41. A transparent electrode layer 48 (not shown) disposed on the light incident surface side of the first semiconductor layer 25 functions as an n-type electrode 41 and discharges electrons generated by photoelectric conversion via the transparent electrode layer 48.

[0064] In the second modification, a single electrode 41 is disposed for each pixel region 21, so there is no need to provide an electrode 41 for each diffusion layer 27, and the manufacturing process can be simplified.

[0065] On the other hand, because the electrode 41 covers most of the pixel region 21, a large capacitance is formed between the electrode 41 and the second semiconductor layer 26, which may cause problems such as a decrease in readout speed. Therefore, a structure that reduces the capacitance between the electrode 41 and the second semiconductor layer 26 may be considered.

[0066] Fig. 13 is a plan view of a solid-state imaging device 1c according to a third modified example of the first embodiment, and Fig. 14 is a cross-sectional view taken along line A-A' in Fig. 13. In the solid-state imaging device 1c according to the third modified example, an individual electrode 41 is disposed for each diffusion layer 27, and each electrode 41 is disposed separately.

[0067] The plurality of electrodes 41 are connected to a wiring layer (conductive member) 43 via contacts 42 extending upward. An insulating layer 44 made of SiO2, SiN, or the like is disposed between the wiring layer 43 and the plurality of electrodes 41. The wiring layer 43 is electrically connected to the plurality of electrodes 41 and is disposed opposite the plurality of diffusion layers 27 with the plurality of electrodes 41 sandwiched therebetween.

[0068] The wiring layer 43 is disposed so as to cover the entire area of ​​the second semiconductor layer 26. Therefore, there is a risk that capacitance may be formed between the wiring layer 43 and the second semiconductor layer 26, but since the distance between the wiring layer 43 and the second semiconductor layer 26 is much longer than the distance between the electrode 41 and the second semiconductor layer 26 shown in FIG.

[0069] In this way, in the first embodiment, a plurality of diffusion sections are provided at intervals along the long sides of the rectangular pixel region 21, so even if the pixel separation section 22 is provided, charges generated by photoelectric conversion near the pixel separation section 22 can be easily transferred to the nearest diffusion layer 27. Therefore, the probability of charge recombination with dark current due to defects caused by forming the pixel separation section 22 can be reduced, and a decrease in quantum efficiency can be suppressed.

[0070] Second Embodiment A solid-state imaging device 10 according to a second embodiment is characterized in that it can suppress crosstalk even if it has a structure that does not include a pixel separation unit 22. When crosstalk occurs, a reduction in resolution occurs, such as blurring of the contours of a captured image, so the solid-state imaging device 10 according to the second embodiment is characterized in that it can improve the quality of a captured image.

[0071] The solid-state imaging device 10 according to the second embodiment has the same block configuration as that shown in Fig. 1. The solid-state imaging device 10 according to the second embodiment can have a stacked structure in which a plurality of chips (substrates) are stacked, as shown in Fig. 2. The solid-state imaging device 10 according to the second embodiment is characterized in that it can be used as a line sensor.

[0072] The solid-state imaging device 10 according to the second embodiment includes a photoelectric conversion layer containing a compound semiconductor material, and a plurality of light-shielding members 45 arranged at a distance from each other on the light incident surface side of the photoelectric conversion layer.

[0073] The photoelectric conversion layer is divided into a plurality of pixel regions 21, each of which is arranged in a first direction X and a second direction Y that intersect with each other. Of the plurality of pixel regions 21, one of two pixel regions 21 arranged adjacent to each other in the first direction X is covered with a light-shielding member 45. Also, of the plurality of pixel regions 21, one of two pixel regions 21 arranged adjacent to each other in the second direction Y is covered with a light-shielding member 45, and each light-shielding member 45 is arranged to cover the entire area of ​​the corresponding pixel region 21.

[0074] 15 is a plan view of a solid-state imaging device 10 according to the second embodiment. The solid-state imaging device 10 according to the second embodiment includes at least two pixel rows, each including a plurality of pixel regions 21 arranged in a first direction X. Hereinafter, these two pixel rows (pixel groups) will be referred to as a first pixel row (first pixel group) PL1 and a second pixel row (second pixel group) PL2.

[0075] In each of the first pixel row PL1 and the second pixel row PL2, pixel regions 21 covered with the light blocking member 45 and pixel regions 21 not covered with the light blocking member 45 are arranged alternately in the first direction X.

[0076] In both the first direction X and the second direction Y, one of two adjacent pixel regions 21 is covered with the light-shielding member 45, and the other is not covered with the light-shielding member 45. When the first pixel row PL1 and the second pixel row PL2 are combined, the pixel regions 21 that are not covered with the light-shielding member 45 are arranged in a staggered pattern.

[0077] Since light from the light incident surface is not incident on the pixel region 21 covered with the light-shielding member 45, photoelectric conversion does not occur within the pixel region 21. Therefore, photoelectric conversion occurs only in the pixel region 21 that is not covered with the light-shielding member 45. In this specification, the pixel region 21 that is not covered with the light-shielding member 45 may be referred to as an effective pixel, and the pixel region 21 that is covered with the light-shielding member 45 may be referred to as an ineffective pixel.

[0078] In this way, only one of two adjacent pixel regions 21 is covered by the light-shielding member 45 in both the first direction X and the second direction Y. Therefore, even if charges generated by photoelectric conversion flow from a pixel region 21 not covered by the light-shielding member 45 into an adjacent pixel region 21 in the first direction X or the second direction Y, the adjacent pixel region 21 is an ineffective pixel that is not used for photoelectric conversion, and therefore does not become a factor that degrades the image quality of the captured image, such as by reducing the resolution.

[0079] 16 is a plan view of a solid-state imaging device 101 according to a comparative example. The solid-state imaging device 101 according to the comparative example includes pixel rows each including a plurality of pixel regions 21 arranged in a first direction X. Each pixel region 21 constituting a pixel row is not covered with a light-shielding member 45, and each pixel region 21 performs photoelectric conversion. Therefore, charges photoelectrically converted near the pixel boundary of each pixel region 21 easily flow into adjacent pixel regions 21, causing a decrease in resolution.

[0080] The light blocking member 45 provided in the pixel region 21 according to the second embodiment can be configured as either a light reflecting layer or a light absorbing layer.

[0081] 17A is a cross-sectional view when the light blocking member 45 is a light reflecting layer 46, and Fig. 17B is a cross-sectional view when the light blocking member 45 is a light absorbing layer 47. In Fig. 17A and Fig. 17B, the light blocking member 45 is disposed at a distance from the light incident surface side of the first semiconductor layer 25.

[0082] 17A and 17B show an example in which the photoelectric conversion layer has a stacked structure in which a second semiconductor layer 26 and a third semiconductor layer 29 are disposed on both sides of a first semiconductor layer 25. The first semiconductor layer 25, the second semiconductor layer 26, and the third semiconductor layer 29 are all III-V compound semiconductor layers. The second semiconductor layer 26 and the third semiconductor layer 29 have a larger energy gap than the first semiconductor layer 25. A diffusion layer 27 is disposed from the surface of the second semiconductor layer 26 opposite the interface with the first semiconductor layer 25, penetrating the second semiconductor layer 26, and into the inside of the first semiconductor layer 25. One or more diffusion layers 27 are provided for each pixel region 21. The diffusion layer 27 contains impurity ions of a conductivity type different from that of the first semiconductor layer 25 and the second semiconductor layer 26. The first semiconductor layer 25 is made of, for example, n-type InGaAs, the second semiconductor layer 26 and the third semiconductor layer 29 are made of, for example, n+-type InP, and the diffusion layer 27 contains, for example, p+-type impurity ions. A non-diffusion layer 28 that does not contain p-type impurity ions is disposed between two adjacent diffusion layers 27.

[0083] 17A, when the light blocking member 45 is configured with the light reflecting layer 46, a metal material with high reflectivity is used. Specific examples of the metal material include tungsten (W) and aluminum (Al).

[0084] A transparent electrode layer 48 is usually disposed on the light incident surface side of the photoelectric conversion layer. Therefore, when the light blocking member 45 is used as the light reflecting layer 46, as shown in FIG. 17A, a SiO ２ Alternatively, it is desirable to provide an insulating layer 49 such as SiN to ensure electrical insulation between the light blocking member 45 and the transparent electrode layer 48 .

[0085] When the light blocking member 45 is configured with the light absorbing layer 47 , the material of the light blocking member 45 can be a semiconductor material such as InGaAs or InAs, and can be disposed directly on the transparent electrode layer 48 .

[0086] The location of the light blocking member 45 in the solid-state imaging device 10 according to the second embodiment is not necessarily limited to the location shown in FIG. 15, and various modifications are possible.

[0087] 18 is a plan view of a solid-state imaging device 10a according to a first modified example of the second embodiment. The solid-state imaging device 10a according to the first modified example includes three pixel rows arranged adjacent to each other in the second direction Y. Hereinafter, the three pixel rows will be referred to as a first pixel row PL1, a third pixel row PL3, and a second pixel row PL2 in order of arrangement in the second direction Y.

[0088] In the first pixel row PL1 and the second pixel row PL2, pixel regions 21 that are not covered with the light-shielding member 45 and pixel regions 21 that are covered with the light-shielding member 45 are alternately arranged in the first direction X. Also in the second direction Y, in the first pixel row PL1 and the second pixel row PL2, pixel regions 21 that are not covered with the light-shielding member 45 and pixel regions 21 that are covered with the light-shielding member 45 are alternately arranged in the first direction X.

[0089] Between the first pixel row PL1 and the second pixel row PL2 in the second direction Y, a third pixel row PL3 is arranged, the entire pixel region 21 of which is covered with a light blocking member 45.

[0090] According to the first modified example shown in FIG. 18, the distance between the first pixel row PL1 and the second pixel row PL2 in the second direction Y can be increased more than in FIG. 15, making crosstalk less likely to occur.

[0091] 19 is a plan view of a solid-state imaging device 10b according to a second modification of Embodiment 2. The solid-state imaging device 10b according to the second modification includes four pixel rows arranged adjacent to each other in the second direction Y.

[0092] Of the four pixel rows, the arrangement of the pixel regions 21 covered with the light-shielding member 45 is the same for the upper two pixel rows PL1, PL2 and the lower two pixel rows PL1, PL2 in the second direction Y. That is, the second modified example has a configuration in which two multi-pixel row regions PLG1, PLG2, each including the first pixel row PL1 and the second pixel row PL2 shown in Figure 15, are arranged side by side in the second direction Y. Note that three or more multi-pixel row regions PLG1, PLG2, each including the first pixel row PL1 and the second pixel row PL2, may be arranged side by side in the second direction Y.

[0093] Fig. 20 is a plan view of a solid-state imaging device 10c according to a third modification of the second embodiment. The solid-state imaging device 10c according to the third modification has a configuration in which two pixel row regions, each including the first pixel row PL1 and the second pixel row PL2 shown in Fig. 15, are arranged side by side in the second direction Y, sandwiching a third pixel row PL3 in which all pixel regions 21 are covered with a light-shielding member 45. Two or more of the five pixel rows shown in Fig. 20 may be arranged in the second direction Y, sandwiching the third pixel row PL3 therebetween.

[0094] Fig. 21 is a plan view of a solid-state imaging device 10d according to a fourth modification of the second embodiment. The solid-state imaging device 10d according to the fourth modification has a configuration in which two pixel row regions PLG1, PLG2, each including a first pixel row PL1, a third pixel row PL3, and a second pixel row PL2 shown in Fig. 18, are arranged in the second direction Y with the third pixel row PL3 sandwiched therebetween. Note that three or more pixel row regions, each including the first pixel row PL1, the third pixel row PL3, and the second pixel row PL2 shown in Fig. 18, may be arranged in the second direction Y with the third pixel row PL3 sandwiched therebetween.

[0095] 22 is a plan view of a solid-state imaging device 10e according to a fifth modification of the second embodiment. The solid-state imaging device 10e according to the fifth modification includes three pixel rows PL1 to PL3, and the positions of pixels covered by the light-shielding members 45 included in each pixel row are shifted in the second direction Y. As a further modification of the fifth modification, the solid-state imaging device 10e may include four or more pixel rows, and the positions of pixels covered by the light-shielding members 45 included in each pixel row may be shifted in the second direction Y.

[0096] As described above, in the second embodiment, a solid-state imaging device 1 that does not include a pixel separation portion 22 includes at least two pixel rows, and at least one of two pixel regions 21 that are arranged adjacent to each other in the first direction X and the second direction Y is covered with a light-shielding member 45. As a result, even if charges generated by photoelectric conversion in a pixel region 21 that is not covered with the light-shielding member 45 flow into an adjacent pixel region 21 in the first direction X or the second direction Y, the pixel region 21 is covered with the light-shielding member 45 and is not an effective pixel that performs photoelectric conversion, and therefore there is no risk of the quality of the captured image being degraded.

[0097] <Application to a Mobile Body> The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0098] FIG. 23 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0099] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 23, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (Interface) 12053.

[0100] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0101] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0102] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0103] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0104] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0105] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the distance between vehicles, maintaining vehicle speed, vehicle collision warning, vehicle lane departure warning, etc.

[0106] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0107] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12030 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0108] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying information to vehicle occupants or the outside of the vehicle. In the example of Fig. 23, the output devices are exemplified by an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0109] FIG. 24 is a diagram showing an example of the installation position of the imaging unit 12031.

[0110] In FIG. 24, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0111] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided on the top of the windshield inside the vehicle cabin is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0112] 24 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0113] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0114] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation.

[0115] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0116] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0117] An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging unit 12031 and the like among the configurations described above. More specifically, the solid-state imaging device 1 according to the present disclosure can be applied to the imaging unit 12031. By applying the technology according to the present disclosure to the imaging unit 12031 and the like, it is possible to obtain a captured image that is easier to see, thereby reducing driver fatigue.

[0118] The present technology can be configured as follows:

[0119] (1) A solid-state imaging device comprising: a first semiconductor layer of a first conductivity type that performs photoelectric conversion; a second semiconductor layer of the first conductivity type that is disposed on a surface opposite to a light incident surface of the first semiconductor layer, includes a material having a larger band gap than the first semiconductor layer, and performs photoelectric conversion; a diffusion layer of a second conductivity type that is disposed from a surface of the second semiconductor layer opposite to an interface with the first semiconductor layer, penetrating the second semiconductor layer to an interior of the first semiconductor layer; an electrode connected to the diffusion layer on a surface of the second semiconductor layer opposite to the interface with the first semiconductor layer; and a pixel separation portion that is disposed in a depth direction of the first semiconductor layer and the second semiconductor layer along a plurality of pixel regions that divide the first semiconductor layer and the second semiconductor layer, wherein a plurality of the diffusion layers are disposed in each of the plurality of pixel regions. (2) The solid-state imaging device described in (1), wherein each of the plurality of pixel regions has a rectangular shape having a short side and a long side longer than the short side when viewed in a plane, and the plurality of diffusion layers included in one of the pixel regions are arranged spaced apart from each other along the long side of the pixel region when viewed in a plane. (3) A solid-state imaging device comprising: a first semiconductor layer of a first conductivity type that performs photoelectric conversion; a second semiconductor layer of the first conductivity type that is disposed on a surface opposite to a light incident surface of the first semiconductor layer, contains a material having a larger band gap than the first semiconductor layer, and performs photoelectric conversion; a diffusion layer of a second conductivity type that is disposed from a surface opposite to an interface between the second semiconductor layer and the first semiconductor layer, penetrating the second semiconductor layer to an interior of the first semiconductor layer; and an electrode connected to the diffusion layer on a surface opposite to the interface between the first semiconductor layer and the second semiconductor layer, wherein each of a plurality of pixel regions obtained by dividing the first semiconductor layer and the second semiconductor layer has a rectangular shape having short sides and long sides longer than the short sides in a plan view, and a plurality of the diffusion layers are disposed in each of the plurality of pixel regions along the long sides. (4) The solid-state imaging device according to (3), further comprising: a pixel separating portion that is disposed along a boundary of the plurality of pixel regions in a depth direction of the first semiconductor layer and the second semiconductor layer.(5) The solid-state imaging device according to any one of (2) to (4), wherein the plurality of diffusion layers are arranged along a center of a short side of each of the plurality of pixel regions and spaced apart in the direction of the long side. (6) The solid-state imaging device according to (1), (2), or (4), wherein the pixel separation portion is arranged along the long side of each of the plurality of pixel regions. (7) The solid-state imaging device according to any one of (1) to (6), wherein the first semiconductor layer and the second semiconductor layer are III-V compound semiconductor layers. (8) The solid-state imaging device according to any one of (1) to (7), wherein each of the plurality of diffusion layers is a diffusion layer containing impurity ions of a second conductivity type, and the second semiconductor layer is arranged between two adjacent diffusion layers and has a non-diffusion layer not containing the impurity ions of the second conductivity type. (9) The solid-state imaging device according to any one of (1) to (8), wherein the electrode is provided for each of the plurality of pixel regions and is connected to the plurality of diffusion layers in the corresponding pixel region. (10) The solid-state imaging device according to any one of (1) to (8), wherein the electrode is provided separately for each of the plurality of diffusion layers in the corresponding pixel region and connected to the corresponding diffusion layer. (11) The solid-state imaging device according to (10), further comprising a conductive member connected to the plurality of electrodes and arranged facing the plurality of diffusion layers with the plurality of electrodes sandwiched therebetween. (12) The solid-state imaging device according to (12), further comprising: a photoelectric conversion layer including a compound semiconductor material; and a plurality of light-shielding members each arranged separately on a light incident surface side of the photoelectric conversion layer, wherein the photoelectric conversion layer is divided into a plurality of pixel regions arranged in a first direction and a second direction intersecting each other, wherein one of two pixel regions arranged adjacent to each other in the first direction is covered with the light-shielding member and the other is not covered with the light-shielding member, and wherein one of two pixel regions arranged adjacent to each other in the second direction is covered with the light-shielding member and the other is not covered with the light-shielding member.(13) The solid-state imaging device described in (12), wherein the photoelectric conversion layer includes: a first semiconductor layer of a first conductivity type that performs photoelectric conversion; a second semiconductor layer of the first conductivity type that is arranged on the surface opposite to the light incident surface of the first semiconductor layer, contains a material having a larger band gap than the photoelectric conversion layer, and performs photoelectric conversion; and a diffusion layer of a second conductivity type that is arranged from the surface opposite to the interface between the second semiconductor layer and the first semiconductor layer, through the second semiconductor layer, to the inside of the first semiconductor layer; and the plurality of light-shielding members are arranged spaced apart from each other on the light incident surface side of the first semiconductor layer. (14) The solid-state imaging device according to (12) or (13), comprising: a first pixel group including two or more of the pixel regions arranged along the first direction; and a second pixel group arranged adjacent to the first pixel group in the second direction and including two or more of the pixel regions arranged along the first direction, wherein all of the pixel regions in the first pixel group that are not covered with the light-shielding member and all of the pixel regions in the second pixel group that are not covered with the light-shielding member are arranged so as to be shifted from each other in the first direction. (15) The solid-state imaging device according to (14), wherein two or more pixel group regions each including the first pixel group and the second pixel group arranged adjacent to each other in the second direction are arranged along the second direction. (16) The solid-state imaging device according to (15), comprising: a third pixel group arranged between two pixel group regions arranged adjacent to each other in the second direction, wherein all of the two or more pixel regions arranged along the first direction are covered with the light-shielding member. (17) A solid-state imaging device according to (16), comprising: a first pixel group including two or more pixel regions arranged along the first direction; a second pixel group arranged apart from the first pixel group in the second direction and including two or more pixel regions arranged along the first direction; and a third pixel group arranged between the first pixel group and the second pixel group in the second direction, in which all of the two or more pixel regions arranged along the first direction are covered with the light-shielding member, wherein all pixel regions in the first pixel group that are not covered with the light-shielding member and all pixel regions in the second pixel group that are not covered with the light-shielding member are arranged offset from each other in the first direction.(18) The solid-state imaging device according to (17), comprising a plurality of pixel group regions respectively arranged in the second direction in the order of the first pixel group, the third pixel group, and the second pixel group, wherein the third pixel group is arranged between two of the pixel group regions arranged adjacently in the second direction. (19) The solid-state imaging device according to (12) or (13), comprising a plurality of pixel groups arranged along the second direction, each including two or more of the pixel regions arranged along the first direction, wherein pixel regions in each of the plurality of pixel groups that are not covered by the light-shielding member are arranged so as to be shifted in the first direction. (20) The solid-state imaging device according to any one of (12) to (19), wherein the light-shielding member is a light-reflecting layer that reflects incident light or a light-absorbing layer that absorbs incident light.

[0120] The aspects of the present disclosure are not limited to the individual embodiments described above, but include various modifications that may be conceived by those skilled in the art, and the effects of the present disclosure are not limited to the above-described contents. In other words, various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and spirit of the present disclosure, which is derived from the contents defined in the claims and their equivalents.

[0121] REFERENCE SIGNS LIST 1, 1a, 1b, 1c solid-state imaging device, 2 pixel region, 3 circuit section, 10, 10a, 10b, 10c, 10d, 10e solid-state imaging device, 11 pixel chip, 12 circuit chip, 20 pixel, 21 pixel region, 22 pixel separation section, 23 opening, 24 insulating layer, 25 first semiconductor layer, 26 second semiconductor layer, 27 diffusion layer, 28 non-diffusion layer, 29 third semiconductor layer, 31 row scanning section, 32 horizontal selection section, 33 column scanning section, 34 system control section, 35 pixel drive line, 36, 37 signal line, 41 electrode, 42 contact, 43 wiring layer, 44 insulating layer, 45 light-shielding member, 46 light-reflecting layer, 47 light-absorbing layer, 48 transparent electrode layer, 49 insulating layer, 100, 100a, 101 solid-state imaging device

Claims

1. A solid-state imaging device comprising: a first semiconductor layer of a first conductivity type that performs photoelectric conversion; a second semiconductor layer of a first conductivity type that is arranged on a surface side opposite to a light incident surface of the first semiconductor layer, contains a material having a larger band gap than the first semiconductor layer, and performs photoelectric conversion; a diffusion layer of a second conductivity type that is arranged from the surface side of the second semiconductor layer opposite to an interface with the first semiconductor layer, penetrating the second semiconductor layer to an interior of the first semiconductor layer; an electrode connected to the diffusion layer on the surface side of the second semiconductor layer opposite to the interface with the first semiconductor layer; and a pixel separation section that is arranged in a depth direction of the first semiconductor layer and the second semiconductor layer along a plurality of pixel regions that divide the first semiconductor layer and the second semiconductor layer, and a plurality of the diffusion layers are arranged in each of the plurality of pixel regions.

2. The solid-state imaging device of claim 1, wherein each of the plurality of pixel regions is rectangular in shape having a short side and a long side longer than the short side when viewed in a plane, and the plurality of diffusion layers included in one of the pixel regions are arranged at a distance from each other along the long side of the pixel region when viewed in a plane.

3. A solid-state imaging device comprising: a first semiconductor layer of a first conductivity type that performs photoelectric conversion; a second semiconductor layer of a first conductivity type that is arranged on a surface side opposite to a light incident surface of the first semiconductor layer, contains a material having a larger band gap than the first semiconductor layer, and performs photoelectric conversion; a diffusion layer of a second conductivity type that is arranged from the surface side of the second semiconductor layer opposite to an interface with the first semiconductor layer, penetrating the second semiconductor layer to an interior of the first semiconductor layer; and an electrode connected to the diffusion layer on the surface side of the second semiconductor layer opposite to the interface with the first semiconductor layer, wherein each of a plurality of pixel regions obtained by dividing the first semiconductor layer and the second semiconductor layer has a rectangular shape having short sides and long sides longer than the short sides when viewed in a plan view, and a plurality of the diffusion layers are arranged along the long sides in each of the plurality of pixel regions.

4. The solid-state imaging device according to claim 3, further comprising a pixel separating section disposed in a depth direction of the first semiconductor layer and the second semiconductor layer along a boundary between the plurality of pixel regions.

5. The solid-state imaging device according to claim 2, wherein the plurality of diffusion layers are arranged spaced apart in the direction of the long sides along the center of the short sides of each of the plurality of pixel regions.

6. The solid-state imaging device according to claim 2, wherein the pixel separating portion is disposed along the long side of each of the plurality of pixel regions.

7. The solid-state imaging device according to claim 1, wherein the first semiconductor layer and the second semiconductor layer are III-V compound semiconductor layers.

8. The solid-state imaging device according to claim 1, wherein each of the plurality of diffusion layers is a diffusion layer containing impurity ions of a second conductivity type, and the second semiconductor layer is disposed between two adjacent diffusion layers and has a non-diffusion layer that does not contain the impurity ions of the second conductivity type.

9. The solid-state imaging device according to claim 1, wherein the electrode is provided for each of the plurality of pixel regions and is connected to the plurality of diffusion layers in the corresponding pixel region.

10. The solid-state imaging device according to claim 1, wherein the electrodes are provided separately for each of the plurality of diffusion layers in the corresponding pixel region and connected to the corresponding diffusion layer.

11. The solid-state imaging device according to claim 10, further comprising a conductive member connected to the plurality of electrodes and disposed opposite the plurality of diffusion layers with the plurality of electrodes interposed therebetween.

12. A solid-state imaging device comprising: a photoelectric conversion layer containing a compound semiconductor material; and a plurality of light-shielding members each arranged at a distance on the light incident surface side of the photoelectric conversion layer, wherein the photoelectric conversion layer is divided into a plurality of pixel regions each arranged in a first direction and a second direction which intersect with each other, wherein of the plurality of pixel regions, one of two pixel regions arranged adjacent to each other in the first direction is covered by the light-shielding member and the other is not covered by the light-shielding member, and wherein of two pixel regions arranged adjacent to each other in the second direction, one of the two pixel regions arranged adjacent to each other in the second direction is covered by the light-shielding member and the other is not covered by the light-shielding member.

13. The solid-state imaging device of claim 12, wherein the photoelectric conversion layer comprises: a first semiconductor layer of a first conductivity type that performs photoelectric conversion; a second semiconductor layer of a first conductivity type that is arranged on the side opposite to the light incident surface of the first semiconductor layer, contains a material having a larger band gap than the photoelectric conversion layer, and performs photoelectric conversion; and a diffusion layer of a second conductivity type that is arranged from the side opposite to the interface of the second semiconductor layer with the first semiconductor layer, penetrating the second semiconductor layer to the inside of the first semiconductor layer; and the multiple light-shielding members are each arranged at a distance on the light incident surface side of the first semiconductor layer.

14. A solid-state imaging device as described in claim 12, comprising: a first pixel group including two or more of the pixel regions arranged along the first direction; and a second pixel group arranged adjacent to the first pixel group in the second direction and including two or more of the pixel regions arranged along the first direction, wherein all pixel regions in the first pixel group that are not covered by the light-shielding member and all pixel regions in the second pixel group that are not covered by the light-shielding member are arranged offset from each other in the first direction.

15. The solid-state imaging device according to claim 14, wherein two or more pixel group regions each including the first pixel group and the second pixel group arranged adjacent to each other in the second direction are arranged along the second direction.

16. The solid-state imaging device according to claim 15, further comprising a third pixel group arranged between two pixel group regions arranged adjacent to each other in the second direction, and in which all of two or more pixel regions arranged along the first direction are covered by the light-shielding member.

17. A solid-state imaging device as described in claim 16, comprising: a first pixel group including two or more of the pixel regions arranged along the first direction; a second pixel group arranged at a distance in the second direction from the first pixel group and including two or more of the pixel regions arranged along the first direction; and a third pixel group arranged between the first pixel group and the second pixel group in the second direction, and in which all of the two or more pixel regions arranged along the first direction are covered by the light-shielding member, wherein all pixel regions in the first pixel group that are not covered by the light-shielding member and all pixel regions in the second pixel group that are not covered by the light-shielding member are arranged so as to be shifted from each other in the first direction.

18. A solid-state imaging device as described in claim 17, comprising a plurality of pixel group regions arranged in the second direction in the order of the first pixel group, the third pixel group, and the second pixel group, and the third pixel group is arranged between two pixel group regions arranged adjacent to each other in the second direction.

19. A solid-state imaging device as described in claim 12, comprising a plurality of pixel groups arranged along the second direction, each of which includes two or more of the pixel regions arranged along the first direction, and wherein pixel regions in each of the plurality of pixel groups that are not covered by the light-shielding member are arranged so as to be shifted in the first direction.

20. The solid-state imaging device according to claim 12, wherein the light-shielding member is a light-reflecting layer that reflects incident light, or a light-absorbing layer that absorbs incident light.

Images