Light detection circuit

Abstract

[Problem] To provide a light detection device capable of reducing the resistance of a voltage path connected to each pixel. [Solution] This light detection device comprises: a first pixel region having a plurality of effective pixels arranged in a two-dimensional direction; a second pixel region disposed around the first pixel region and having a plurality of dummy pixels; a plurality of first pixel separation members disposed in the pixel boundary region of the plurality of effective pixels in the first pixel region, the first pixel separation member having a conductor; and a plurality of second pixel separation members disposed in the pixel boundary region of the plurality of dummy pixels in the second pixel region, the second pixel separation member having the conductor. The plurality of first pixel separation members and the plurality of second pixel separation members are set to a predetermined voltage level by the conductors.

Description

Photodetection Circuit

[0001] The present disclosure relates to a photodetection circuit.

[0002] A dToF (direct Time of Flight) ranging device is known, which irradiates an object with light emitted from a light-emitting device, receives reflected light from the object by a light-receiving device, and measures the distance to the object based on the time difference between the light emission timing of the light-emitting device and the light reception timing of the light-receiving device.

[0003] A light-receiving device provided in this type of ranging device has a plurality of pixels arranged in a two-dimensional direction, and a light-receiving element is provided for each pixel to detect light reception timing. Therefore, the ranging device can perform distance measurement for each pixel. Each pixel detects incident photons using, for example, a SPAD (Single Photon Avalanche Diode).

[0004] When the anodes of each SPAD are set to a common voltage level (for example, a ground voltage level), a reverse bias voltage is supplied to the cathodes, and a photon is detected, the cathode voltage decreases and a pulse signal is generated.

[0005] As described above, the cathode of the SPAD of each pixel must always be set to the same voltage level. In Patent Document 1, a light shielding member provided in a pixel boundary region of each pixel is connected to the cathode of the SPAD, and each light shielding member is electrically connected to a power supply unit of a circuit chip via a contact provided outside the pixel array. The contacts are provided for each pixel row.

[0006] International Publication No. WO 2024 / 024515

[0007] In Patent Document 1, the plurality of contacts provided for each pixel row outside the pixel array are provided only along one side of the pixel array, and the light shielding members of all pixels in the corresponding pixel row are connected to each contact, so that parasitic resistance increases. This makes it difficult to set the anode voltage of the SPAD of each pixel to a desired voltage level. In addition, a voltage drop occurs from the power supply unit through each contact to the anode of each SPAD, which may increase power consumption.

[0008] Therefore, this disclosure provides an optical detection device that can reduce the resistance of the voltage path connected to each pixel.

[0009] To solve the above problems, the present disclosure provides a photodetector comprising: a first pixel region having a plurality of effective pixels arranged in a two-dimensional direction; a second pixel region arranged to surround the first pixel region and having a plurality of dummy pixels; a plurality of first pixel separation members arranged in the pixel boundary region of the plurality of effective pixels in the first pixel region, each having a conductor; and a plurality of second pixel separation members arranged in the pixel boundary region of the plurality of dummy pixels in the second pixel region, each having the conductor, wherein the plurality of first pixel separation members and the plurality of second pixel separation members are set to a predetermined voltage level by the conductor.

[0010] Each of the plurality of effective pixels has a photodiode, and the conductors of the plurality of first pixel separators and the plurality of second pixel separators are electrically connected to the anodes of the plurality of photodiodes of the plurality of effective pixels, and the anodes may be set to the predetermined voltage level.

[0011] The output nodes of the plurality of dummy pixels may be set to a predetermined voltage level regardless of the presence or absence of incident light, or they may be at an undefined level.

[0012] Each of the plurality of dummy pixels may have a capacitor connected between the corresponding output node and the conductor.

[0013] The plurality of first pixel separation members and the plurality of second pixel separation members are arranged in a grid pattern along four sides in a plan view, and the spacing between two adjacent first pixel separation members along each of the four sides may be the same as the spacing between two adjacent second pixel separation members along each of the four sides.

[0014] The plurality of first pixel separation members and the plurality of second pixel separation members are arranged in a grid pattern along four sides in a plan view, and the spacing between two adjacent first pixel separation members along each of the four sides may be different from the spacing between two adjacent second pixel separation members along each of the four sides.

[0015] The plurality of first pixel separation members and the plurality of second pixel separation members are arranged in a grid pattern along four sides in a plan view, and the second pixel region may have a plurality of the second pixel separation members arranged along each of the four sides.

[0016] The silicon layer may include a first diffusion region provided along each of the four sides and surrounded by four second pixel separation members arranged adjacently in the two-dimensional direction, a plurality of contacts electrically connected to the first diffusion region, and a wiring layer electrically connected to the plurality of contacts.

[0017] A plurality of the silicon layers and a plurality of the first diffusion regions are arranged along each of the four sides, and the wiring layer may be connected to a plurality of contacts provided for each of the plurality of first diffusion regions.

[0018] The system may include a conductive member positioned between the first diffusion region and the plurality of contacts.

[0019] The first conductive layer is positioned in a location that overlaps with the plurality of second pixel separation regions in a plan view and is connected to the conductor of each of the plurality of second pixel separation members, and the first conductive layer and the first diffusion region may be arranged to be in contact with each other.

[0020] The device may also include: a plurality of first conductive layers arranged in a position overlapping with the plurality of second pixel separation regions in a plan view and connected to the conductor of each of the plurality of second pixel separation members; a plurality of contacts connected to each of the plurality of first conductive layers; and a plurality of wiring layers connected to each of the plurality of contacts.

[0021] The contact may be made of a metal or polysilicon.

[0022] The device comprises a third pixel region having a plurality of light-shielding pixels and positioned between the first pixel region and the second pixel region, and a plurality of third pixel separation members positioned in the pixel boundary region of the plurality of light-shielding pixels in the third pixel region, each having the conductor, wherein the plurality of first pixel separation members, the plurality of second pixel separation members, and the plurality of third pixel separation members may be set to the predetermined voltage level by the conductor.

[0023] The device comprises two first pixel regions and two third pixel regions, wherein one third pixel region is arranged to surround one first pixel region, the other first pixel region is arranged to surround the one third pixel region, the other third pixel region is arranged to surround the other first pixel region, and the second pixel region is arranged to surround the other third pixel region, and the plurality of effective pixels in the one first pixel region and the plurality of effective pixels in the other first pixel region may output different types of signals.

[0024] A silicon layer surrounded by four of the aforementioned second pixel separation members, which are connected to the light incident surface side of the plurality of second pixel separation members and include a light-shielding member having the conductive material, may have a second diffusion region connected to the light-shielding member.

[0025] The silicon layer comprises: a third pixel region having a plurality of light-shielding pixels and positioned between the first pixel region and the second pixel region; a plurality of third pixel separation members, each having the conductor, positioned in the pixel boundary region of the plurality of light-shielding pixels in the third pixel region; and a light-shielding member having the conductor, connected to the light incident surface side of the plurality of second pixel separation members and the third pixel separation member, wherein the silicon layer surrounded by four of the second pixel separation members positioned adjacent to each other in the two-dimensional direction has a third diffusion region connected to the light-shielding member, and the third diffusion region may be the cathode region of the photodiodes of each of the plurality of light-shielding pixels.

[0026] The device includes a guard ring region arranged to surround the second pixel region, wherein the guard ring region may have the conductor or, without the conductor, an insulating layer.

[0027] The device may also include a guard ring region arranged to surround the second pixel region, and a contact region between the guard ring region and the second pixel region, which is arranged to surround the second pixel region and in which a plurality of contacts connected to the conductors of each of the plurality of second pixel separating members are arranged.

[0028] Each of the plurality of effective pixels is a SPAD (Single Photon Avalanche Diode), and the conductor may be set to the anode voltage of the SPAD.

[0029] A block diagram showing the schematic configuration of the photodetector according to the present disclosure. A plan view of the vicinity of the corner of the pixel array portion of the photodetector according to the first embodiment. A cross-sectional view of the line A-A' in Figure 2 in the first embodiment. A plan view of the vicinity of the corner of the pixel array portion of the photodetector according to a comparative example. A cross-sectional view of the line A-A' in Figure 4. A cross-sectional view of the line A-A' in Figure 2 in the second embodiment. A cross-sectional view of the line A-A' in Figure 2 in the third embodiment. A cross-sectional view of the line A-A' in Figure 2 in the fourth embodiment. A cross-sectional view showing the cross-sectional structure of capacitor C. A cross-sectional view showing the cross-sectional structure of effective pixel PX1. A cross-sectional view of the line A-A' in Figure 2 in the fifth embodiment. A cross-sectional view of the line A-A' in Figure 2 in the sixth embodiment. A cross-sectional view of the line A-A' in Figure 2 in the seventh embodiment. A cross-sectional view of the line A-A' in Figure 2 in a modified example of the seventh embodiment. A cross-sectional view of the line A-A' in Figure 2 in the eighth embodiment. A cross-sectional view of the line A-A' in Figure 2 in the ninth embodiment. A plan view of the area near the corner of the pixel array of the photodetector according to the 10th embodiment. A plan view of a part of one side of the pixel array of the photodetector according to the 11th embodiment. A plan view of a part of one side of the pixel array of the photodetector according to the 12th embodiment. A plan view of a part of one side of the pixel array of the photodetector according to the 13th embodiment. An equivalent circuit diagram of the first to third pixel regions of the photodetector according to the 14th embodiment. An equivalent circuit diagram of the first to third pixel regions of the photodetector according to the first modified example of the 14th embodiment. An equivalent circuit diagram of the first to third pixel regions of the photodetector according to the second modified example of the 14th embodiment. An equivalent circuit diagram of the first to third pixel regions of the photodetector according to the third modified example of the 14th embodiment. An equivalent circuit diagram of the first to third pixel regions of the photodetector according to the fourth modified example of the 14th embodiment. A block diagram showing an example of the schematic configuration of a vehicle control system. An explanatory diagram showing an example of the installation positions of the external information detection unit and the imaging unit.

[0030] The embodiments of the photodetector will be described below with reference to the drawings. While the main components of the photodetector will be described below, there may be components and functions not shown or described in the drawings. The following description does not exclude any components or functions not shown or described.

[0031] Figure 1 is a block diagram showing the schematic configuration of the photodetector 1 according to the present disclosure. As shown in Figure 1, the photodetector 1 according to the present disclosure comprises a pixel array unit 2, a column drive unit 3, a signal processing unit 4, and a histogram generation unit 5.

[0032] The pixel array section 2 has a plurality of pixels PX arranged in two dimensions (first direction and second direction). Each pixel PX has a SPAD 6, a quench circuit 7, and a pulse generation circuit 8.

[0033] The anode voltage of SPAD6 is fixed to, for example, the ground voltage. During the period when SPAD6 detects the incidence of a photon, a reverse bias voltage higher than the anode voltage is supplied to the cathode of SPAD6 by the quench circuit 7. When SPAD6 detects the incidence of a photon, it lowers the cathode voltage. The pulse generation circuit 8 has, for example, an inverter and generates a pulse signal by inverting the cathode voltage of SPAD6.

[0034] The quench circuit 7 performs a process to restore the original reverse bias voltage when the cathode voltage of the SPAD 6 drops. The quench circuit 7 may be an active quench circuit using active elements such as transistors, or a passive quench circuit using passive elements such as resistors.

[0035] The column drive unit 3 outputs a drive signal for each pixel column. An AND circuit 9 is provided at the output node of each pixel PX. The AND circuit 9 outputs a logical AND signal of the pulse signal output from each pixel PX and the drive signal output from the column drive unit 3. When the drive signal is at a high level, the AND circuit 9 outputs a pulse signal.

[0036] Each pixel row is connected to a signal processing unit 4 having an OR circuit 10 and a TDC (Time Digital Converter) 11. Each OR circuit 10 outputs a signal obtained by taking the logical OR of the output signals of a plurality of AND circuits 9 provided in the corresponding pixel row.

[0037] The output signal of each OR circuit 10 is input to the TDC 11. The TDC 11 converts the output signal of each OR circuit 10 into a digital signal. This digital signal represents the time information when the SPAD 6 detected the photon.

[0038] The digital signals output from each TDC 11 are input to the histogram generation unit 5. The histogram generation unit 5 generates a histogram representing the frequency of times when each SPAD 6 detected a photon. The distance to the object is measured from the peak position of this histogram.

[0039] The photodetector 1 according to this disclosure is composed of a single-layer semiconductor chip, or a semiconductor chip having a first layer and a second layer stacked on top of each other. In the latter case, the first layer is arranged on the light incident surface side and has, for example, a pixel array section 2. The second layer is arranged on the opposite side from the light incident surface and has, for example, a column drive section 3, a signal processing section 4, and a histogram generation section 5.

[0040] The photodetector 1 according to this disclosure is characterized by reducing the resistance of the voltage path connected to the anode of the photodiode of each pixel PX. In the following description, an example in which the photodiode of each pixel PX is a SPAD6 will be mainly explained, but the photodetector 1 according to this disclosure is also applicable when each pixel PX is a grayscale pixel that outputs a pixel signal containing grayscale information, or when each pixel PX is an EVS (Event Based Vision Sensor) that outputs an event signal containing event information.

[0041] (First Embodiment) Figure 2 is a plan view of the area near the corner of the pixel array section 2 of the light detection device 1 according to the first embodiment, and Figure 3 is a cross-sectional view taken along line A-A' in Figure 2 in the first embodiment. The pixel array section 2 has a rectangular shape as shown in Figure 1, and a planar shape similar to the area near the corner in Figure 2 extends in two dimensions.

[0042] In this specification, the plurality of pixels PX in the pixel array unit 2 are referred to as effective pixels PX1, and the arrangement area of ​​the pixel array unit 2 is referred to as the first pixel area 21. Each pixel PX in the first pixel area 21 has a SPAD 6 as described above. The anodes of each SPAD 6 are set to the same voltage level (for example, the ground voltage level).

[0043] In the pixel boundary region of the plurality of effective pixels PX1 in the first pixel region 21, as shown in FIG. 3, a plurality of first pixel separation members 22 are provided. The plurality of first pixel separation members 22 extend in the depth direction of the substrate. As shown in FIG. 2, the plurality of first pixel separation members 22 are arranged in a grid pattern along four sides in a plan view. Each of the plurality of first pixel separation members 22 comprises a conductor 20, and each of them is electrically conductive.

[0044] A region surrounded by four first pixel separation members 22 arranged adjacently in a two-dimensional direction is a region of each pixel PX, and a SPAD 6 is arranged in this region. A contact 48 connected to the cathode electrode of the SPAD 6 is arranged on the lower surface of the central portion of this region.

[0045] The photodetection device 1 according to the first embodiment comprises a second pixel region 24 arranged to surround the first pixel region 21. The second pixel region 24 has a plurality of dummy pixels PX2. A dummy pixel PX2 is a pixel that does not detect photons. The output node of the dummy pixel PX2 may be preset to a predetermined voltage level, or may be in an indeterminate state. The second pixel region 24 is a pull-in portion for setting the anode voltage of each SPAD 6 in the second pixel region 24.

[0046] In the pixel boundary region of the plurality of dummy pixels PX2 in the second pixel region 24, a plurality of second pixel separation members 25 are provided. The plurality of second pixel separation members 25 extend in the depth direction of the substrate. As shown in FIG. 2, the plurality of second pixel separation members 25 are arranged in a grid pattern along four sides in a plan view. Each of the plurality of second pixel separation members 25 comprises a conductor 20, and each of them is electrically conductive. Each dummy pixel PX2 is arranged in a region surrounded by four second pixel separation members 25 arranged in a two-dimensional direction.

[0047] The first pixel separation members 22 and the second pixel separation members 25 are set to a predetermined voltage level by the conductors 20. The conductors 20 comprised by the plurality of first pixel separation members 22 and the plurality of second pixel separation members 25 are electrically connected to the anodes of the plurality of SPADs 6 comprised by the plurality of effective pixels PX1, and the anodes are set to a predetermined voltage level.

[0048] In the first embodiment, the interval between two first pixel separation members 22 arranged adjacent to each other along each of the four sides is the same as the interval between two second pixel separation members 25 arranged adjacent to each other along each of the four sides.

[0049] The photodetection device 1 according to the first embodiment includes a third pixel region 26 arranged between the first pixel region 21 and the second pixel region 24. The third pixel region 26 has a plurality of light-shielding pixels PX3. A light-shielding pixel PX3 is a pixel in which a light-shielding member 27 that shields incident light is disposed. Like the dummy pixels PX2, the light-shielding pixels PX3 do not detect photons.

[0050] In the pixel boundary regions of the plurality of light-shielding pixels PX3 in the third pixel region 26, a plurality of third pixel separation members 28 are provided. The plurality of third pixel separation members 28 extend in the depth direction of the substrate. As shown in FIG. 2, the plurality of third pixel separation members 28 are arranged in a grid pattern within the third pixel region 26 in a plan view. Each of the plurality of third pixel separation members 28 includes a conductor 20, and each is electrically conductive. Each light-shielding pixel PX3 is arranged in a region surrounded by four third pixel separation members 28 arranged in a two-dimensional direction.

[0051] The photodetection device 1 according to the first embodiment includes a guard ring 29 arranged so as to surround the second pixel region 24. The guard ring 29 electrically separates an inner region and an outer region of the guard ring 29. The conductor 20 is connected to the guard ring 29. This conductor 20 is formed in the step of forming the conductors 20 of the first to third pixel separation members 22, 25, and 28.

[0052] The photodetection device 1 according to the first embodiment has a plurality of contacts 30 arranged at regular intervals so as to surround the guard ring 29. These contacts 30 are set to, for example, a ground voltage level.

[0053] The photodetection device 1 according to the first embodiment includes a plurality of pads 32 arranged so as to surround the plurality of contacts 30. Bonding wires (not shown) are connected to these pads 32.

[0054] Figure 3 shows an example in which the light detection device 1 according to the first embodiment is formed in a single layer. The top surface of Figure 3 is the light incident surface.

[0055] As shown in Figure 3, a color filter layer 42 is placed on top of a silicon layer 41, and an on-chip lens layer 43 is placed on top of that. Note that Figure 3 shows a simplified representation of the first layer configuration, and in reality, multiple layers not shown in Figure 3 may be stacked.

[0056] As shown in Figure 3, a plurality of second pixel separation members 25 are arranged in the second pixel region 24. Light-shielding members 27 are connected to the upper surfaces of the plurality of second pixel separation members 25. The light-shielding members 27 are arranged from the second pixel region 24 to the third pixel region 26. Since both the plurality of second pixel separation members 25 and the light-shielding members 27 have a conductor 20, they are electrically conductive to each other.

[0057] The second pixel region 24 has a plurality of second pixel separation members 25 arranged along each of its four sides. A first diffusion region 44 is provided in the center of the lower surface of the silicon layer 41 surrounded by four second pixel separation members 25 arranged adjacently in the two-dimensional direction. The first diffusion region 44 is a diffusion region containing P-type or N-type impurity ions.

[0058] The first diffusion region 44 is in contact with a conductive layer (first conductive layer) 45 connected to the lower end of the second pixel separation member 25. The conductive layer 45 is, for example, a polysilicon layer. When viewed from the light incident surface, the second pixel separation member 25 and the conductive layer 45 overlap in at least a portion. By bringing the first diffusion region 44 into contact with the conductive layer 45, the second pixel separation member 25, the silicon layer 41, and the light-shielding member 27 can be electrically connected.

[0059] Multiple contacts 31 are connected to the first diffusion region 44. Each contact 31 is made of a conductive material. The conductive material of each contact 31 is, for example, a metallic material such as tungsten (W), copper (Cu), or aluminum (Al), or polysilicon.

[0060] A wiring layer 46 is connected to multiple contacts 31. The wiring layer 46 is a metal layer, such as copper (Cu). The wiring layer 46 may be composed of multiple layers via contacts or vias. A predetermined voltage is applied to the wiring layer 46. This voltage is transmitted to the conductors 20 of the first to third pixel separation members 22, 25, and 28 via the wiring layer 46 and the contacts 31.

[0061] More specifically, multiple dummy pixels PX2 are arranged along each of the four sides, and multiple first diffusion regions 44 are arranged along each side. Multiple contacts 31 are connected to each of the multiple first diffusion regions 44. These contacts are connected to a common wiring layer 46. In this specification, multiple contacts 31 connected to one first diffusion region 44 are referred to as a contact group 31.

[0062] Thus, in the first embodiment, each of the four sides has a plurality of contact groups 31 connected to the wiring layer 46, and each contact group 31 is connected to the corresponding first diffusion region 44. This allows the voltage paths connected to the wiring layer 46 to be distributed.

[0063] Light-shielding members 27 are connected to the upper surfaces of multiple third pixel separation members 28 within the third pixel region 26. Since both the multiple third pixel separation members 28 and the light-shielding members 27 have a conductor 20, they are electrically conductive to each other.

[0064] A third diffusion region 47 is provided in the center of the lower surface of the silicon layer 41, which is surrounded by four third pixel separation members 28 arranged adjacently in the two-dimensional direction. The third diffusion region 47 is a diffusion region containing, for example, N-type impurity ions. The third diffusion region 47 corresponds to the cathode of the light-shielding pixel PX3. A contact 48 is connected to the third diffusion region 47, and a wiring layer 46 is connected to the contact 48. The contact 48 and the contact 31 may be formed from the same conductive material or using the same manufacturing process.

[0065] A P-type diffusion region 49 is arranged around the lower surfaces of the first to third pixel separation members 22, 25, and 28 within the first to third pixel regions 21, 24, and 26, and around the conductive layer 45. This P-type diffusion region 49 corresponds to the anode region of the SPAD 6, dummy pixel PX2, or light-shielding pixel PX3.

[0066] Figure 4 is a plan view of the area near the corner of the pixel array section 2 of the optical detection device 1 according to one comparative example. As shown in Figure 4, in one comparative example, the second pixel region 24 in the first embodiment does not exist, and instead a retraction section 11 is provided. The retraction section 11 in one comparative example is arranged to surround the third pixel region 26. Although the retraction section 11 in one comparative example has a plurality of contacts 12, they are not separated for each pixel PX and do not have a pixel separation member.

[0067] Figure 5 is a cross-sectional view taken along the line A-A' in Figure 4. The pull-in section 11 according to one comparative example has, for example, a diffusion region 13 containing P-type impurity ions and a high-concentration P-type diffusion region 14 positioned between the diffusion region 13 and the light-shielding member 27. A P-type diffusion region 49 is positioned on the lower surface of this diffusion region 13, and a plurality of contacts 12 are connected to the P-type diffusion region 49. These contacts 12 are connected to the wiring layer 46 and are electrically connected to the conductor 20 of the third pixel separation member 28 and the light-shielding member 27 via the diffusion region 13 and the P-type diffusion region 14. Since there is only one conductive member 15 on each side, the parasitic resistance is large, and the anode voltage of the SPAD 6 of each effective pixel PX1 may fluctuate to the desired voltage level. In addition, if the parasitic resistance is large, the power consumption will also increase.

[0068] In contrast, in the first embodiment, a second pixel separation member 25 is arranged in a grid pattern in the second pixel region 24 surrounding the first pixel region 21 of the pixel array 2, and the conductor 20 of the second pixel separation member 25 and the silicon layer 41 of each dummy pixel PX2 are electrically connected to the wiring layer 46 via a plurality of contacts 31. This allows the voltage supplied from the wiring layer 46 to be distributed across multiple voltage paths, and the resistance of each voltage path can be reduced. This makes it possible to stabilize the anode voltage of the SPAD 6 of each effective pixel PX1.

[0069] (Second Embodiment) The light detection device 1 according to the second embodiment has a planar layout similar to that of Figure 2, but the cross-sectional structure along line A-A' is different from that of the first embodiment.

[0070] Figure 6 is a cross-sectional view taken along line A-A' in Figure 2 in the second embodiment. In the first embodiment shown in Figure 3, the contact 31 is directly connected to the first diffusion region 44 of the silicon layer 41. If the contact 31 is made of a metallic material such as tungsten (W), the contact with the first diffusion region 44 is not good. Therefore, in the second embodiment, a plurality of polysilicon layers (conductive members) 51 are connected to the first diffusion region 44, and these polysilicon layers 51 are connected to a plurality of contacts 31 made of a metallic material. The plurality of contacts 31 are connected to the wiring layer 46 in the same way as in the first embodiment shown in Figure 3.

[0071] The photodetector 1 according to the second embodiment has a stacked structure in which a first layer LY1 and a second layer LY2 are stacked, as shown in Figure 6. The first layer LY1 and the second layer LY2 transmit and receive various signals via contacts 31. The first layer LY1 has an effective pixel PX1, a light-shielding pixel PX3, and a dummy pixel PX2. The first layer LY1 also has the polysilicon layer 51 described above. The second layer LY2 has the column drive unit 3, signal processing unit 4, histogram generation unit 5 shown in Figure 1, and a wiring layer 46. As shown in Figure 6, the second layer LY2 has a plurality of transistors 33 that constitute the column drive unit 3, signal processing unit 4, and histogram generation unit 5.

[0072] Thus, in the second embodiment, by arranging multiple polysilicon layers 51 between the first diffusion region 44 and the multiple contacts 31, contactability can be improved and resistance can be further reduced.

[0073] (Third Embodiment) The light detection device 1 according to the third embodiment has a planar layout similar to that of Figure 2, but the cross-sectional structure along line A-A' differs from that of the first embodiment.

[0074] Figure 7 is a cross-sectional view taken along line A-A' in Figure 2 in the third embodiment. In the third embodiment shown in Figure 7, there is a conductive layer 45 connected to the lower end of each second pixel separation member 25 in the second pixel region 24. Contacts 31 are connected to these conductive layers 45. These contacts 31 are connected to a wiring layer (M1 wiring layer) 46. A conductive layer 52 connected to the lower end of the third pixel separation member 28 in the third pixel region 26 is in a floating state.

[0075] In the third embodiment, the silicon layer 41 of each dummy pixel PX2 within the second pixel region 24 does not have a first diffusion region 44, and there are no multiple contacts 31. Therefore, the pixel structure of the second pixel region 24 can be simplified compared to the first and second embodiments.

[0076] The photodetector 1 according to the third embodiment has a stacked structure in which a first layer LY1 and a second layer LY2 are stacked, similar to the second embodiment. The first layer LY1 and the second layer LY2 transmit and receive various signals via contacts 31.

[0077] Thus, in the third embodiment, a desired voltage can be supplied to a plurality of second pixel isolation members 25 within the second pixel region 24 via the corresponding conductive layer 45, contact 31, and wiring layer 46. In the third embodiment as well, the voltage paths supplying the desired voltage are distributed, and the resistance of the plurality of second pixel isolation members 25 can be reduced, thereby suppressing fluctuations in the anode voltage of the SPAD 6 of each effective pixel PX1.

[0078] (Fourth Embodiment) The photodetector 1 according to the fourth embodiment has a planar layout similar to that of Figure 2, but the cross-sectional structure along line A-A' differs from that of the first to third embodiments.

[0079] Figure 8 is a cross-sectional view taken along the line A-A' in Figure 2 in the fourth embodiment. In the fourth embodiment shown in Figure 8, each dummy pixel PX2 in the second pixel region 24 has a capacitor C. This capacitor C is provided on the voltage path connected to the anode of the SPAD6 of each effective pixel PX1.

[0080] The photodetector 1 according to the fourth embodiment has a stacked structure in which a first layer LY1 and a second layer LY2 are stacked, similar to the second embodiment. The first layer LY1 and the second layer LY2 transmit and receive various signals via contacts 31.

[0081] Figure 9 is a cross-sectional view showing the cross-sectional structure of capacitor C. Figure 10 is a cross-sectional view showing the cross-sectional structure of effective pixel PX1.

[0082] As shown in Figures 8 and 9, a silicon layer 41 surrounded by four adjacent second pixel separation members 25 in the two-dimensional direction is provided with an N-type diffusion region 53 in which, for example, N-type impurity ions are implanted at a high concentration. At the lower end of this N-type diffusion region 53, a first N-type diffusion region 44 containing even more N-type impurity ions than the N-type diffusion region 53 is arranged. A contact 31 is connected to this first diffusion region 44. This contact 31 is connected to a wiring layer 46. A conductive layer 45, for example, made of a polysilicon layer 51, is connected to the lower end of the second pixel separation member 25. As a result, a capacitor C is formed with the wiring layer 46 and the conductive layer 45 as two electrodes, with the N-type diffusion region 53 sandwiched between them. Since the capacitor C is connected to the voltage path that leads to the anode of the SPAD 6 of each effective pixel PX1, it suppresses voltage fluctuations in this voltage path.

[0083] On the other hand, as shown in Figure 10, the effective pixel PX1 does not have an N-type diffusion region 53 in which N-type impurity ions are implanted at a high concentration. However, the effective pixel PX1 is provided with a P-type diffusion region 49 for the anode around the lower end of the first pixel separation member 22. This P-type diffusion region 49 is not necessary for the dummy pixel PX2.

[0084] In this way, by providing a capacitor C in each dummy pixel PX2 within the second pixel region 24, voltage fluctuations in the conductors 20 of the first and second pixel separation members 22 and 25 can be suppressed. Therefore, the anode voltage of the SPAD 6 of each effective pixel PX1 can be stabilized.

[0085] (Fifth Embodiment) The photodetector 1 according to the fifth embodiment has a planar layout similar to that of Figure 2, but the cross-sectional structure along line A-A' differs from that of the first to fourth embodiments.

[0086] Figure 11 is a cross-sectional view taken along line A-A' in Figure 2 in the fifth embodiment. The second pixel region 24 in the fifth embodiment shown in Figure 11 has, in addition to the cross-sectional structure of Figure 3, a P-type diffusion region (second diffusion region) 54 located near the upper surface of the silicon layer 41 of each dummy pixel PX2. This P-type diffusion region 54 is connected to a light-shielding member 27 which is connected to the upper surface of the second pixel separation member 25.

[0087] This improves the contact between the conductor 20 of the second pixel separation member 25 and the light-shielding member 27 and the silicon layer 41, making it possible to further reduce the resistance of the voltage path connected to the anode of the SPAD 6 of each effective pixel PX1.

[0088] Furthermore, in the fifth embodiment, the guard ring 29 is formed of an N-type diffusion region 55, and no contacts are connected to the guard ring 29. Such a guard ring 29 is also applicable to the guard ring 29 of the first to fourth embodiments described above.

[0089] (Sixth Embodiment) The photodetector 1 according to the sixth embodiment has a planar layout similar to that of Figure 2, but the cross-sectional structure along line A-A' differs from that of the first to fifth embodiments.

[0090] Figure 12 is a cross-sectional view taken along line A-A' in Figure 2 in the sixth embodiment. In the first to fifth embodiments described above, a P-type diffusion region 49 for the anode is arranged around the lower ends of the first to third pixel separation members 22, 25, and 28. However, in the sixth embodiment shown in Figure 12, a P-type diffusion region (third diffusion region) 49 is arranged around the upper ends of the first to third pixel separation members 22, 25, and 28. This ensures a distance between the P-type diffusion region 49 for the anode and the N-type diffusion region 47 for the cathode, enabling miniaturization of the pixel PX. In other words, if the P-type diffusion region 49 and the N-type diffusion region 47 are arranged in close proximity, a strong PN junction is formed between them, limiting the reduction of the pixel PX size. However, in the sixth embodiment, it is easier to ensure a distance between the P-type diffusion region 49 and the N-type diffusion region 47, allowing for a further reduction in the pixel PX size.

[0091] (Seventh Embodiment) The photodetector 1 according to the seventh embodiment has a planar layout similar to that of Figure 2, but the cross-sectional structure along line A-A' differs from that of the first to sixth embodiments.

[0092] Figure 13 is a cross-sectional view of the line A-A' in Figure 2 in the seventh embodiment, and Figure 14 is a cross-sectional view of the line A-A' in Figure 2 in a modified example of the seventh embodiment. The seventh embodiment shown in Figures 13 and 14 is characterized by shortening the lengths of the first pixel separation member 22 in the first pixel region 21 and the second pixel separation member 25 in the second pixel region 24 compared to Figure 12.

[0093] The first pixel separation member 22 and the second pixel separation member 25 shown in Figures 13 and 14 share the common characteristic of having a length that does not penetrate the silicon layer 41. The first pixel separation member 22 and the second pixel separation member 25 shown in Figure 13 extend from the upper surface (back surface) of the silicon layer 41 to a position higher than the lower surface of the silicon layer 41. On the other hand, the first pixel separation member 22 and the second pixel separation member 25 shown in Figure 14 extend from the lower surface of the silicon layer 41 to a position lower than the upper surface of the silicon layer 41.

[0094] In this way, by shortening the lengths of the first pixel separation member 22 and the second pixel separation member 25, light can more easily enter the effective pixel PX1, thereby improving the sensitivity of the SPAD 6. Although it is possible to shorten the lengths of the first pixel separation member 22 and the second pixel separation member 25, it is not desirable to eliminate the first pixel separation member 22 and the second pixel separation member 25. The reason is that since a high voltage is applied between the anode and cathode of the SPAD 6, there is a risk that it will emit light itself, and if some SPAD 6 emit light, there is a risk that adjacent SPAD 6 will react, so it is not desirable to eliminate the first pixel separation member 22 and the second pixel separation member 25.

[0095] (Eighth Embodiment) The light detection device 1 according to the eighth embodiment has a planar layout similar to that of Figure 2, but the cross-sectional structure along line A-A' differs from that of the first to seventh embodiments.

[0096] Figure 15 is a cross-sectional view taken along line A-A' in Figure 2 in the eighth embodiment. In the eighth embodiment shown in Figure 15, the cross-sectional structure of the guard ring 29 differs from that in Figure 11. In the guard ring 29 according to the eighth embodiment shown in Figure 15, a conductor 20 is connected, similar to the third pixel separation member 28. This conductor 20 can be formed in the process of forming the first to third pixel separation members 22, 25, and 28. This simplifies the process of forming the guard ring 29.

[0097] (Ninth Embodiment) The photodetector 1 according to the ninth embodiment has a planar layout similar to that of Figure 2, but the cross-sectional structure along line A-A' differs from that of the first to seventh embodiments.

[0098] Figure 16 is a cross-sectional view taken along line A-A' in Figure 2 in the ninth embodiment. The ninth embodiment shown in Figure 16 differs from the cross-sectional structure in Figure 6 in that a P-type diffusion region 54 is arranged along the upper surface of the silicon layer 41 of each dummy pixel PX2 in the second pixel region 24. By providing the P-type diffusion region 54, the conductor 20 of the second pixel separation member 25, the silicon layer 41, and the light-shielding member 27 in the second pixel region 24 can be set to the same voltage level, and the conductor 20 of the first to third pixel separation members 22, 25, and 28 can be made to have a lower resistance.

[0099] (Tenth Embodiment) The light detection device 1 according to the tenth embodiment has a different planar layout from that shown in Figure 2.

[0100] Figure 17 is a plan view of the area near the corner of the pixel array section 2 of the light detection device 1 according to the tenth embodiment. The pixel array section 2 has a rectangular shape as shown in Figure 1, and a planar shape similar to that of the area near the corner in Figure 2 extends in two dimensions.

[0101] In Figure 2, the spacing between the two first pixel separation members 22, which are arranged adjacently along each of the four sides, and the spacing between the two second pixel separation members 25, which are arranged adjacently along each of the four sides, are the same. In contrast, in the tenth embodiment shown in Figure 17, the spacing between the two first pixel separation members 22, which are arranged adjacently along each of the four sides, and the spacing between the two second pixel separation members 25, which are arranged adjacently along each of the four sides, are made different. For example, in the tenth embodiment shown in Figure 17, the spacing between the two second pixel separation members 25, which are arranged adjacently along each of the four sides, is made narrower than the spacing between the two first pixel separation members 22, which are arranged adjacently along each of the four sides. This makes it possible to reduce the size of the second pixel region 24, and thus reduce the chip size of the light detection device 1. Furthermore, in the tenth embodiment, even if the size of the second pixel region 24 is reduced, the number of contacts is not reduced, so the anode voltage of the SPAD 6 of each effective pixel PX1 can be stabilized, similar to the first embodiment.

[0102] (Eleventh Embodiment) The light detection device 1 according to the eleventh embodiment has a different planar layout from that shown in Figure 2.

[0103] Figure 18 is a plan view of a part of one side of the pixel array section 2 of the light detection device 1 according to the eleventh embodiment. The pixel array section 2 has a rectangular shape as shown in Figure 1, and a planar shape similar to that in Figure 18 extends in the two-dimensional direction.

[0104] In the eleventh embodiment shown in Figure 18, a process dummy pixel region 56 is provided between the second pixel region 24 and the third pixel region 26. The process dummy pixel region 56 has a plurality of process dummy pixels PX4, mainly for suppressing variations in the semiconductor process. Each process dummy pixel PX4 has a pixel structure similar to that of an effective pixel PX1, but does not perform photon detection.

[0105] The second pixel region 24 is arranged to surround the process dummy pixel region 56. The cross-sectional structure of the second pixel region 24 has the same pixel structure as in the first to ninth embodiments described above, and the same effects can be obtained.

[0106] (Twelfth Embodiment) The light detection device 1 according to the twelfth embodiment has a different planar layout from that shown in Figure 2.

[0107] Figure 19 is a plan view of a part of one side of the pixel array section 2 of the light detection device 1 according to the twelfth embodiment. In the twelfth embodiment shown in Figure 19, two first pixel regions 21 and two third pixel regions 26 are provided. One third pixel region 26a is arranged to surround one first pixel region 21a. The other first pixel region 21b is arranged to surround one third pixel region 26a. The other third pixel region 26b is arranged to surround the other first pixel region 21b. A second pixel region 24 is arranged to surround the other third pixel region 26b.

[0108] Multiple effective pixels PX1 in one first pixel region 21a and multiple effective pixels PX1 in the other first pixel region 21b output different types of signals. For example, multiple effective pixels PX1 in one first pixel region 21a are used for photon detection. Multiple effective pixels PX1 in the other first pixel region 21b are used for setting the driving conditions of the pixels PX, or for monitoring the characteristics of the pixels PX, or at least one of the above. The second pixel region 24 has a pixel structure similar to that of the first to ninth embodiments described above, and similar effects can be obtained.

[0109] (Third Embodiment) The light detection device 1 according to the thirteenth embodiment has a different planar layout from that shown in Figure 2.

[0110] Figure 20 is a plan view of a part of one side of the pixel array section 2 of the optical detection device 1 according to the 13th embodiment. In the 13th embodiment, a contact area 57 is provided between the guard ring 29 and the second pixel area 24, and is arranged to surround the second pixel area 24. The contact area 57 has a plurality of contacts 58 arranged in a two-dimensional direction, and each contact 58 is electrically connected to the conductor 20 of each of the plurality of second pixel separation members 25, and is also connected to the wiring layer 46. More specifically, it has two or more contacts 58 connected to the conductor 20 of each of the plurality of second pixel separation members 25. This makes it possible to make the conductors 20 of the first to third pixel separation members 22, 25, and 28 even more resistance.

[0111] (Fourteenth Embodiment) Various variations are possible for the equivalent circuits of the first to third pixel regions 21, 24, and 26 in the light detection device 1 according to the first to thirteenth embodiments. Several representative equivalent circuits will be described below.

[0112] Figure 21 is an equivalent circuit diagram of the first to third pixel regions 21, 24, and 26 of the light detection device 1 according to the 14th embodiment. The equivalent circuit in Figure 21 corresponds, for example, to the first embodiment shown in Figure 3. The multiple effective pixels PX1 in the first pixel region 21 of Figure 21 have multiple SPADs 6 and a readout circuit and a pixel control circuit 61 connected to the cathode of each SPAD 6. The anode of each SPAD 6 is electrically connected to the conductor 20 of the first pixel separation member 22. The multiple light-shielded pixels PX3 in the second pixel region 24 have multiple light-shielded SPADs 6. The cathodes of the multiple light-shielded SPADs 6 are connected to the ground voltage node. The anodes of the multiple light-shielded SPADs 6 are electrically connected to the conductor 20 of the second pixel separation member 25. The multiple dummy pixels PX2 in the third pixel region 26 are equivalently represented by low-resistance resistive elements.

[0113] Figure 22 is an equivalent circuit diagram of the first to third pixel regions 21, 24, and 26 of a photodetector 1 according to a first modification of the 14th embodiment. The equivalent circuit in Figure 22 corresponds to, for example, the third embodiment shown in Figure 7. The multiple light-shielding pixels PX3 in the second pixel region 24 of Figure 22 have multiple light-shielding SPAD6 whose cathodes are in an undefined state. The circuit configuration of the first pixel region 21 and the third pixel region 26 in Figure 22 is the same as in Figure 21.

[0114] Figure 23 is an equivalent circuit diagram of the first to third pixel regions 21, 24, and 26 of a photodetector 1 according to a second modification of the 14th embodiment. The equivalent circuit in Figure 23 corresponds to the fourth embodiment shown in Figure 8. The second pixel region 24 in the equivalent circuit of Figure 23 has a plurality of capacitors C formed in a plurality of dummy pixels PX2. Each capacitor C includes an N-type diffusion region 53 in which, for example, a high concentration of N-type impurity ions is implanted into the silicon layer 41 of the dummy pixel PX2. The circuit configuration of the first pixel region 21 and the third pixel region 26 according to the second modification is the same as in Figure 21.

[0115] Figure 24 is an equivalent circuit diagram of the first to third pixel regions 21, 24, and 26 of the photodetector 1 according to a third modification of the 14th embodiment. In the third modification, the silicon layer 41 of the light-shielding pixel PX3 in the third pixel region 26 includes a high-density N-type diffusion region. The equivalent circuit of the second pixel region 24 is the same as in Figure 21.

[0116] Figure 25 is an equivalent circuit diagram of the first to third pixel regions 21, 24, and 26 of the photodetector 1 according to the fourth modification of the fourteenth embodiment. In the fourth modification shown in Figure 25, the second pixel region 24 has an equivalent circuit that is a combination of the equivalent circuits of Figures 21 and 23. Also, the third pixel region 26 in the fourth modification has the same equivalent circuit as in Figure 24.

[0117] <Examples of application to mobile devices> The technology disclosed herein (this technology) can be applied to various products. For example, the technology disclosed herein may be implemented as a device mounted on any type of mobile device such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, and robots.

[0118] Figure 26 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0119] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 26, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0120] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0121] The body system control unit 12020 controls the operation of various devices mounted on 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 system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0122] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0123] The imaging unit 12031 is a light 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.

[0124] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that captures images of the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0125] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the external information detection unit 12030 or the internal 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 ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0126] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0127] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0128] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 26, the output devices include 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 onboard display and a head-up display.

[0129] Figure 27 shows an example of the installation position of the imaging unit 12031.

[0130] In Figure 27, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0131] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0132] Figure 27 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0133] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0134] For example, the microcomputer 12051, based on distance information obtained from the imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to the vehicle 12100). In particular, it can extract the closest object on the vehicle 12100's path that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0135] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies 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 the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid collisions by outputting a warning to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0136] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio-image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio-image output unit 12052 may also control the display unit 12062 to display an icon indicating a pedestrian at a desired position.

[0137] The above describes an example of a vehicle control system to which the technology described herein may be applied. The technology described herein may be applied to the imaging unit 12031, etc., among the configurations described above.

[0138] Furthermore, this technology can take the following configurations: (1) A photodetector comprising: a first pixel region having a plurality of effective pixels arranged in a two-dimensional direction; a second pixel region arranged to surround the first pixel region and having a plurality of dummy pixels; a plurality of first pixel separation members arranged in the pixel boundary region of the plurality of effective pixels in the first pixel region, each having a conductor; and a plurality of second pixel separation members arranged in the pixel boundary region of the plurality of dummy pixels in the second pixel region, each having the conductor, wherein the plurality of first pixel separation members and the plurality of second pixel separation members are set to a predetermined voltage level by the conductor. (2) The photodetector according to (1), wherein each of the plurality of effective pixels has a photodiode, the conductors of the plurality of first pixel separation members and the plurality of second pixel separation members are electrically connected to the anodes of the plurality of photodiodes of the plurality of effective pixels, and the anodes are set to the predetermined voltage level. (3) The photodetector according to (1) or (2), wherein the output nodes of the plurality of dummy pixels are set to a predetermined voltage level regardless of the presence or absence of incident light, or are at an undefined level. (4) The photodetector according to (1) or (2), wherein each of the plurality of dummy pixels has a capacitor connected between the corresponding output node and the conductor. (5) The photodetector according to any one of (1) to (4), wherein the plurality of first pixel separators and the plurality of second pixel separators are arranged in a grid along four sides in a plan view, and the spacing between two of the first pixel separators arranged adjacent to each of the four sides is the same as the spacing between two of the second pixel separators arranged adjacent to each of the four sides. (6) The optical detection device according to any one of (1) to (4), wherein the plurality of first pixel separation members and the plurality of second pixel separation members are arranged in a grid pattern along four sides in a plan view, and the spacing between two adjacent first pixel separation members along each of the four sides is different from the spacing between two adjacent second pixel separation members along each of the four sides.(7) The photodetector according to any one of (1) to (6), wherein the plurality of first pixel separation members and the plurality of second pixel separation members are arranged in a grid along four sides in a plan view, and the second pixel region has a plurality of the second pixel separation members arranged along each of the four sides. (8) The photodetector according to (7), comprising: a first diffusion region disposed in a silicon layer surrounded by four second pixel separation members provided along each of the four sides and arranged adjacently in a two-dimensional direction; a plurality of contacts electrically connected to the first diffusion region; and a wiring layer electrically connected to the plurality of contacts. (9) The photodetector according to (8), wherein a plurality of the silicon layers and a plurality of the first diffusion regions are arranged along each of the four sides, and the wiring layer is connected to the plurality of contacts provided for each of the plurality of first diffusion regions. (10) The photodetector according to (8) or (9), comprising a conductive member disposed between the first diffusion region and the plurality of contacts. (11) The photodetector according to any one of (8) to (10), comprising a first conductive layer positioned in a plan view to overlap with the plurality of second pixel separation regions and connected to the conductor of each of the plurality of second pixel separation members, wherein the first conductive layer and the first diffusion region are arranged to be in contact with each other. (12) The photodetector according to (7), comprising a plurality of first conductive layers positioned in a plan view to overlap with the plurality of second pixel separation regions and connected to the conductor of each of the plurality of second pixel separation members, a plurality of contacts connected to each of the plurality of first conductive layers, and a plurality of wiring layers connected to each of the plurality of contacts. (13) The photodetector according to any one of (8) to (12), wherein the contacts are made of a metallic material or polysilicon.(14) The photodetector according to any one of (1) to (13), comprising: a third pixel region disposed between the first pixel region and the second pixel region and having a plurality of light-shielding pixels; and a plurality of third pixel separation members disposed in the pixel boundary region of the plurality of light-shielding pixels in the third pixel region, each having the conductor, wherein the plurality of first pixel separation members, the plurality of second pixel separation members, and the plurality of third pixel separation members are set to the predetermined voltage level by the conductor. (15) The photodetector according to (14), comprising two first pixel regions and two third pixel regions, wherein one third pixel region is arranged to surround one first pixel region, the other first pixel region is arranged to surround the one third pixel region, the other third pixel region is arranged to surround the other first pixel region, and the second pixel region is arranged to surround the other third pixel region, wherein the plurality of effective pixels in the one first pixel region and the plurality of effective pixels in the other first pixel region output signals of different types from each other. (16) The photodetector according to any one of (8) to (15), comprising a light-shielding member having the conductive material connected to the light incident surface side of the plurality of second pixel separation members, wherein a silicon layer surrounded by four second pixel separation members arranged adjacently in a two-dimensional direction has a second diffusion region connected to the light-shielding member. (17) The photodetector according to any one of (1) to (13), comprising: a third pixel region disposed between the first pixel region and the second pixel region and having a plurality of light-shielding pixels; a plurality of third pixel separation members disposed in the pixel boundary region of the plurality of light-shielding pixels in the third pixel region, each having the conductor; and a light-shielding member having the conductor and connected to the light incident surface side of the plurality of second pixel separation members and the third pixel separation member, wherein a silicon layer surrounded by four second pixel separation members arranged adjacently in the two-dimensional direction has a third diffusion region connected to the light-shielding member, and the third diffusion region is the cathode region of a photodiode having each of the plurality of light-shielding pixels.(18) A photodetector according to any one of (1) to (17), comprising a guard ring region arranged to surround the second pixel region, wherein the guard ring region has the conductor or, without the conductor, has an insulating layer. (19) A photodetector according to any one of (8) to (17), comprising a guard ring region arranged to surround the second pixel region, and a contact region between the guard ring region and the second pixel region, arranged to surround the second pixel region, in which a plurality of contacts connected to the conductor of each of the plurality of second pixel separating members are arranged. (20) A photodetector according to any one of (1) to (19), wherein each of the plurality of effective pixels is a SPAD (Single Photon Avalanche Diode), and the conductor is set to the anode voltage of the SPAD.

[0139] The aspects of this disclosure are not limited to the individual embodiments described above, but include various modifications that a person skilled in the art could conceive, and the effects of this disclosure are not limited to those described above. In other words, various additions, modifications, and partial deletions are possible, as long as they do not depart from the conceptual idea and spirit of this disclosure derived from the claims and their equivalents.

[0140] 1. Light detection device, 2. Pixel array section, 3. Column drive section, 4. Signal processing section, 5. Histogram generation section, 7. Quench circuit, 8. Pulse generation circuit, 9. AND circuit, 10. OR circuit, 11. Pull-in section, 12. Contact, 13. Diffusion region, 14. P-type diffusion region, 15. Conductive member, 20. Conductor, 21. First pixel region, 22. First pixel separation member, 24. Second pixel region, 25. Second pixel separation member, 26. Third pixel region, 27. Light shielding member, 28. Third pixel separation member, 29. Guard ring, 30. Contact, 31. Contact, 32. Pad, 41. Silicon layer, 42. Color filter layer, 43. On-chip lens layer, 44. First diffusion region, 45. Conductive layer, 46. Wiring layer, 47. N-type diffusion region, 48. Contact, 49. P-type diffusion region, 51. Polysilicon layer, 52. Conductive layer, 53. N-type diffusion region, 54 P-type diffusion region, 55 N-type diffusion region, 56 Process dummy pixel region, 57 Contact region, 58 Contact, 61 Pixel control circuit

Claims

1. A photodetector comprising: a first pixel region having a plurality of effective pixels arranged in a two-dimensional direction; a second pixel region having a plurality of dummy pixels and arranged to surround the first pixel region; a plurality of first pixel separation members arranged in the pixel boundary region of the plurality of effective pixels in the first pixel region, each having a conductor; and a plurality of second pixel separation members arranged in the pixel boundary region of the plurality of dummy pixels in the second pixel region, each having the conductor, wherein the plurality of first pixel separation members and the plurality of second pixel separation members are set to a predetermined voltage level by the conductor.

2. The photodetector according to claim 1, wherein each of the plurality of effective pixels has a photodiode, the conductors of the plurality of first pixel separators and the plurality of second pixel separators are electrically connected to the anodes of the plurality of photodiodes of the plurality of effective pixels, and the anodes are set to the predetermined voltage level.

3. The photodetector according to claim 1, wherein the output nodes of the plurality of dummy pixels are set to a predetermined voltage level regardless of the presence or absence of incident light, or are at an undefined level.

4. The photodetector according to claim 1, wherein each of the plurality of dummy pixels has a capacitor connected between the corresponding output node and the conductor.

5. The photodetector according to claim 1, wherein the plurality of first pixel separation members and the plurality of second pixel separation members are arranged in a grid pattern along four sides in a plan view, and the spacing between two adjacent first pixel separation members along each of the four sides is the same as the spacing between two adjacent second pixel separation members along each of the four sides.

6. The photodetector according to claim 1, wherein the plurality of first pixel separation members and the plurality of second pixel separation members are arranged in a grid pattern along four sides in a plan view, and the spacing between two adjacent first pixel separation members along each of the four sides is different from the spacing between two adjacent second pixel separation members along each of the four sides.

7. The photodetector according to claim 1, wherein the plurality of first pixel separating members and the plurality of second pixel separating members are arranged in a grid pattern along four sides in a plan view, and the second pixel region has a plurality of the second pixel separating members arranged along each of the four sides.

8. The photodetector according to claim 7, comprising: a first diffusion region disposed in a silicon layer surrounded by four second pixel separation members provided along each of the four sides and arranged adjacently in a two-dimensional direction; a plurality of contacts electrically connected to the first diffusion region; and a wiring layer electrically connected to the plurality of contacts.

9. The photodetector according to claim 8, wherein a plurality of silicon layers and a plurality of first diffusion regions are arranged along each of the four sides, and the wiring layer is connected to a plurality of contacts provided for each of the plurality of first diffusion regions.

10. The photodetector according to claim 8, further comprising a conductive member disposed between the first diffusion region and the plurality of contacts.

11. The photodetector according to claim 8, comprising a first conductive layer positioned in a plan view that overlaps with the plurality of second pixel separation regions and connected to the conductor of each of the plurality of second pixel separation members, wherein the first conductive layer and the first diffusion region are arranged to be in contact with each other.

12. The photodetector according to claim 7, comprising: a plurality of first conductive layers arranged in a position overlapping with the plurality of second pixel separation regions in a plan view and connected to the conductor of each of the plurality of second pixel separation members; a plurality of contacts connected to each of the plurality of first conductive layers; and a plurality of wiring layers connected to each of the plurality of contacts.

13. The photodetector according to claim 8, wherein the contact is made of a metal material or polysilicon.

14. The photodetector according to claim 1, comprising: a third pixel region disposed between the first pixel region and the second pixel region and having a plurality of light-shielding pixels; and a plurality of third pixel separation members disposed in the pixel boundary region of the plurality of light-shielding pixels in the third pixel region, each having the conductor, wherein the plurality of first pixel separation members, the plurality of second pixel separation members, and the plurality of third pixel separation members are set to the predetermined voltage level by the conductor.

15. The photodetector according to claim 14, comprising two first pixel regions and two third pixel regions, wherein one third pixel region is arranged to surround one first pixel region, the other first pixel region is arranged to surround the one third pixel region, the other third pixel region is arranged to surround the other first pixel region, and the second pixel region is arranged to surround the other third pixel region, and the plurality of effective pixels in the one first pixel region and the plurality of effective pixels in the other first pixel region output signals of different types from each other.

16. The photodetector according to claim 8, wherein a silicon layer surrounded by four of the second pixel separation members arranged adjacently in a two-dimensional direction has a second diffusion region connected to the light incident surface side of the plurality of second pixel separation members, and comprises a light-shielding member having the conductor.

17. The photodetector according to claim 1, comprising: a third pixel region disposed between the first pixel region and the second pixel region and having a plurality of light-shielding pixels; a plurality of third pixel separation members disposed in the pixel boundary region of the plurality of light-shielding pixels in the third pixel region, each having the conductor; and a light-shielding member having the conductor and connected to the light incident surface side of the plurality of second pixel separation members and the third pixel separation member, wherein a silicon layer surrounded by four second pixel separation members arranged adjacently in the two-dimensional direction has a third diffusion region connected to the light-shielding member, and the third diffusion region is the cathode region of a photodiode having each of the plurality of light-shielding pixels.

18. The photodetector according to claim 1, further comprising a guard ring region arranged to surround the second pixel region, wherein the guard ring region has the conductor or, without the conductor, has an insulating layer.

19. The photodetector according to claim 8, comprising: a guard ring region arranged to surround the second pixel region; and a contact region between the guard ring region and the second pixel region, which is arranged to surround the second pixel region and in which a plurality of contacts connected to the conductors of each of the plurality of second pixel separating members are arranged.

20. The photodetector according to claim 1, wherein each of the plurality of effective pixels is a SPAD (Single Photon Avalanche Diode), and the conductor is set to the anode voltage of the SPAD.

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