Light detection device

Abstract

A light detection device according to one embodiment of the present disclosure includes: a first semiconductor layer having a first surface and a second surface facing each other, and having a single photon avalanche diode as a light receiving element provided for each pixel; an on-chip lens disposed on the second surface side of the first semiconductor layer for each pixel; and a photoelectric conversion layer disposed between the second surface of the first semiconductor layer and the on-chip lens, and an area of the photoelectric conversion layer is smaller than an area of a light receiving portion of the light receiving element in a plan view.

Description

Technical Field

[0001] This disclosure relates to a light detection device using an avalanche photodiode capable of acquiring phase difference information. Background Technology

[0002] For example, Patent Document 1 discloses a sensor chip in which single photon avalanche diode (SPAD) pixels are arranged in an array on a semiconductor substrate, and pixel separation portions are provided between adjacent pixels. [List of Citations] [Patent Literature]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-167249 Summary of the Invention

[0004] Incidentally, in photon counting camera sensors using SPADs, there is a technique that acquires phase difference information by setting an on-chip lens spanning multiple pixels. However, for SPAD pixels without inter-pixel light-blocking walls between phase difference pixels, color mixing is significant due to emission during the doubling period, and the separation ratio between phase difference pixels decreases. Therefore, in light detection devices using avalanche photodiodes capable of acquiring phase difference information, improvements in imaging characteristics are needed.

[0005] The aim is to provide a light detection device that can improve camera characteristics.

[0006] A light detection device according to one embodiment of the present disclosure includes: a first semiconductor layer having a first surface and a second surface opposite to each other, and having a single-photon avalanche diode as a light receiving element disposed for each pixel; an on-chip lens disposed for each pixel on the second surface side of the first semiconductor layer; and a photoelectric conversion layer disposed between the second surface of the first semiconductor layer and the on-chip lens, wherein the area of ​​the photoelectric conversion layer in a plan view is smaller than the area of ​​the light receiving portion of the light receiving element.

[0007] In a photodetector according to one embodiment of the present disclosure, a photoelectric conversion layer is disposed between a first semiconductor layer and an on-chip lens. A single-photon avalanche diode serving as a light-receiving element is disposed in the first semiconductor layer for each pixel. The on-chip lens is arranged for each pixel. The area of ​​the photoelectric conversion layer in a planar view is smaller than the area of ​​the light-receiving portion of the light-receiving element. Therefore, while suppressing the decrease in sensitivity of the light-receiving element, the separation ratio of the photoelectric conversion layer can be ensured. Attached Figure Description

[0008] Figure 1 This is a schematic cross-sectional view showing an example of a light detection device according to a first embodiment of the present disclosure. Figure 2 It is shown Figure 1 A schematic plan view showing the relationship between the light receiving section and the photoelectric conversion layer of the light receiving element. Figure 3 It is shown Figure 1 A block diagram illustrating an example of the schematic construction of the light detection device. Figure 4 It is shown Figure 1 A schematic diagram illustrating an example of the planar layout of phase difference pixels in a light detection device. Figure 5 It is shown Figure 1 A schematic diagram of another example of the planar layout of phase difference pixels in the light detection device shown. Figure 6 It is shown Figure 1 A schematic diagram of yet another example of the planar layout of phase difference pixels in the light detection device shown. Figure 7 It is shown Figure 1 A schematic diagram of another example of the planar layout of phase difference pixels in the light detection device shown. Figure 8 It is shown Figure 1 A schematic diagram of another example of the planar layout of phase difference pixels in the light detection device shown. Figure 9 It is shown Figure 1 The flowchart illustrates an example of the processing flow of the optical detection device during readout. Figure 10 This is a block diagram illustrating an example of a schematic construction of a light detection device according to a variation of this disclosure, Example 1. Figure 11 This is a flowchart illustrating an example of the processing flow of the optical detection device during readout according to a variation of this disclosure, Example 2. Figure 12 This is a schematic cross-sectional view showing an example of a light detection device according to a second embodiment of the present disclosure. Figure 13 It shows the use Figure 1 A block diagram illustrating an example of the construction of an electronic device for a light detection apparatus. Figure 14A It shows the use Figure 1 A schematic diagram illustrating an example of the overall structure of the optical detection system of the optical detection device shown. Figure 14B It is shown Figure 14AA diagram showing an example of the circuit structure of the optical detection system. Figure 15 It shows the use Figure 1 Functional block diagram of an example electronic device for a light detection device, as shown. Figure 16 This is a diagram illustrating an example of a schematic construction of an endoscopic surgical system. Figure 17 This is a block diagram illustrating an example of the functional structure of a camera head and a CCU. Figure 18 This is a block diagram illustrating an example of a schematic construction of a vehicle control system. Figure 19 This is an explanatory diagram showing an example of the installation location of the vehicle exterior information detection unit and the camera unit. Detailed Implementation

[0009] In the following description, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspects. Furthermore, the present disclosure is not limited to the arrangement, dimensions, aspect ratios, etc., of the various components shown in the various drawings. The order of description is as follows. 1. First Implementation Plan (An example of a photodetector in which a photoelectric conversion layer is arranged between a semiconductor layer on which SPAD elements are disposed and an on-chip lens.) 2. Variations 2-1. Modification 1 (Another example of the construction of an optical detection device) 2-2. Variation Example 2 (Another example of the construction of an optical detection device) 3. Second Implementation Plan 4. Applicable Examples 5. Application Examples

[0010] <1. First Implementation Plan> Figure 1 An example of the cross-sectional structure of a light detection device (light detection device 1) according to a first embodiment of the present disclosure is shown schematically. Figure 2 It is shown Figure 1 This is a schematic plan view showing the relationship between the light receiving section 13 of the light receiving element 12 and the photoelectric conversion layer 44. For example, the light detection device 1 is applied to image sensors such as digital cameras and camcorders, as well as distance image sensors that perform distance measurements using the time-of-flight (ToF) method.

[0011] The light detection device 1 has a light receiving element 12 provided for each unit pixel P. The light receiving element 12 has a light receiving portion 13 and a multiplying portion 14, and is disposed in a semiconductor layer 11. The semiconductor layer 11 has a first surface 11S1 and a second surface 11S2 facing each other. On the second surface 11S2 side, which serves as the light incident surface, an on-chip lens 62 is provided for each unit pixel P. In the light detection device 1 of this embodiment, a photoelectric conversion layer 44 is provided between the second surface 11S2 of the semiconductor layer 11 and the on-chip lens 62. In a plan view, the area of ​​the photoelectric conversion layer 44 is smaller than the area of ​​the light receiving portion 13 of the light receiving element 12.

[0012] Here, semiconductor layer 11 corresponds to a specific example of the "first semiconductor layer" in the first embodiment of this disclosure, and light receiving element 12 corresponds to a specific example of the "light receiving element" in the first embodiment of this disclosure. On-chip lens 62 corresponds to a specific example of the "on-chip lens" in the first embodiment of this disclosure, and photoelectric conversion layer 44 corresponds to a specific example of the "photoelectric conversion layer" in the first embodiment of this disclosure.

[0013] [Schematic diagram of the optical detection device]

[0014] The light detection device 1 includes: a light receiving element 12 disposed for each unit pixel P; an on-chip lens 62 disposed for each unit pixel P; and a photoelectric conversion layer 44 disposed between the second surface 11S2 of the semiconductor layer 11 on which the light receiving element 12 is disposed and the on-chip lens 62, and stacked on the light receiving element 12. For example, the light receiving element 12 is a single-photon avalanche diode (SPAD) element. As described above, the area of ​​the photoelectric conversion layer 44 in the plan view is smaller than the area of ​​the light receiving portion 13 of the light receiving element 12, and for example, multiple (e.g., two or four) photoelectric conversion layers 44 are disposed within a unit pixel P. In the light detection device 1, the subject image imaged by the imaging lens is photoelectrically converted by the light receiving element 12 to obtain pixel signals for image generation, and the pupil region of the imaging lens is divided by the photoelectric conversion layer 44, and the subject image from the divided pupil region is photoelectrically converted to obtain pixel signals for phase difference detection. In this way, image plane phase difference autofocus can be performed in the light detection device 1.

[0015] In other words, a unit pixel P includes imaging pixels and image plane phase difference pixels. In the following text, the imaging pixel formed by the SPAD element, which serves as the light receiving element 12, is referred to as a "SPAD pixel." The image plane phase difference pixel formed by the photoelectric conversion layer 44 is referred to as a "phase difference pixel," and when it is necessary to distinguish multiple phase difference pixels disposed within a unit pixel P, P1, P2, P3, and P4 are added after each name. These phase difference pixels correspond to specific examples of "sub-pixels" in the first embodiment of this disclosure.

[0016] In the light detection device 1, for example, a readout circuit board 20 and a logic board 50 are stacked on the front side of the sensor substrate 10 (e.g., the front side (first surface 11S1) of the semiconductor layer 11 that forms the sensor substrate 10), and a photoelectric conversion layer 44 and an on-chip lens 62 are stacked on the back side of the sensor substrate 10 (e.g., the back side (second surface 11S2) of the semiconductor layer 11 that forms the sensor substrate 10). The light detection device 1 is a so-called back-illuminated type light detection device that receives light from the back side of the sensor substrate 10.

[0017] Figure 3 It is shown Figure 1 The diagram shows a schematic construction of the light detection device 1. Note that... Figure 3 The stacking relationship of the various components in the light detection device 1 is shown, and the size of each block is not necessarily completely consistent with the size of the actual components mounted in the device.

[0018] The sensor substrate 10 includes a semiconductor layer 11 having a first surface 11S1 and a second surface 11S2 facing each other. The semiconductor layer 11 has a pixel array portion in which a plurality of unit pixels P are arranged in an array along the row and column directions, and a light-receiving element 12 is disposed in each unit pixel P. The readout circuit substrate 20 includes a semiconductor layer 21 having a front side (surface 21S1) and a back side (surface 21S2) facing each other. A plurality of transistors (e.g., one or more pMOS transistors 211 and one or more nMOS transistors 212) for constituting a readout circuit are disposed in the semiconductor layer 21, which outputs a pixel signal based on the charge output from, for example, a phase difference pixel of the unit pixel P. In this embodiment, the readout circuit includes a readout circuit (photon counting circuit) for acquiring pixel signals from SPAD pixels and a readout circuit (analog-to-digital conversion circuit) for acquiring pixel signals from phase difference pixels. A logic circuit is formed in the logic substrate 50. For example, the logic circuit includes a pixel front end (PFE) circuit 511, a vertical drive circuit 512, an analog-to-digital conversion circuit 513, a photon counting readout circuit 514, and an output circuit 515.

[0019] In the optical detection device 1, such as Figure 3 As shown, SPAD pixels (light receiving element 12) and phase difference pixels (photoelectric conversion layer 44) are stacked on top of each other, and for example, pixel transistors for forming a readout circuit (readout circuit 210) for acquiring pixel signals from the phase difference pixels are formed in the semiconductor layer 21 below the SPAD pixels. For example, a photon counting circuit (PFE circuit 511) for acquiring pixel signals from the SPAD pixels is formed in the logic substrate 50 below the readout circuit 210. In addition, in the logic substrate 50, for example in the periphery of the pixel array section, a vertical drive circuit 512, an analog-to-digital converter circuit 513, a photon counting readout circuit 514, and an output circuit 515 for outputting pixel signals acquired from the phase difference pixels are provided.

[0020] [Cross-sectional structure of the optical detection device] like Figure 1 As shown, for example, the photodetector 1 has a readout circuit board 20 and a logic board 50 stacked on the front side of the sensor substrate 10. On the back side of the sensor substrate 10, a photoelectric conversion layer 44, a protective layer 61, and an on-chip lens 62 are stacked sequentially across an interlayer insulating layer 41 containing a color filter 42.

[0021] Note that the symbols "p" and "n" in the figure represent p-type and n-type semiconductor regions, respectively. Furthermore, the "+" or "-" at the end of "p" indicates the impurity concentration in the p-type semiconductor region. Similarly, the "+" or "-" at the end of "n" indicates the impurity concentration in the n-type semiconductor region. More "+" signs indicate a higher impurity concentration, and more "-" signs indicate a lower impurity concentration. This also applies to the subsequent figures.

[0022] For example, the sensor substrate 10 includes a semiconductor layer 11, and the semiconductor layer 11 has a light-receiving portion 13 and a multiplier portion 14 embedded for each unit pixel P to form a light-receiving element 12. On the first surface 11S1 of the semiconductor layer 11, a contact layer 15 (anode) electrically connected to the light-receiving portion 13 and a contact layer 16 (cathode) electrically connected to the multiplier portion 14 are provided. A pixel separation portion 17 is also provided in the semiconductor layer 11, which electrically separates adjacent unit pixels P from each other.

[0023] For example, the semiconductor layer 11 is made of a silicon (Si) substrate and has a first surface 11S1 and a second surface 11S2 facing each other. The semiconductor layer 11 has a p-well (p) shared by multiple unit pixels P. In the semiconductor layer 11, for each unit pixel P, an n-type semiconductor region (n) 111 is provided for constituting a light receiver 13 and whose impurity concentration is controlled, for example, to be n-type. In the semiconductor layer 11, a p-type semiconductor region (p) is also provided on the first surface 11S1 side. + ) 14X and n-type semiconductor regions (n + These components 14Y are used to form the multiplication section 14. This forms a light-receiving element 12 for each unit pixel P. Around each unit pixel P, a pixel separation section 17 is provided to electrically separate adjacent unit pixels P from each other. Between the light-receiving element 12 and the pixel separation section 17, a p-type semiconductor region (p) 112 with a higher impurity concentration than the p-well is provided.

[0024] The light receiving element 12 converts incident light into an electrical signal via photoelectric conversion and outputs the electrical signal. Incidentally, the light receiving element 12 converts incident light (photons) into an electrical signal via photoelectric conversion and outputs a pulse corresponding to the incident photon. For example, the light receiving element 12 is a single-photon avalanche diode (SPAD) element. A SPAD element has the following characteristics: by applying a large negative voltage to the cathode (contact layer 16) to form an avalanche multiplication region 12X (depletion layer), and causing electrons generated in response to the incident photon to undergo avalanche multiplication, thereby causing a large current to flow.

[0025] The light receiving element 12 is composed of a light receiving section 13 and a multiplier section 14.

[0026] The light receiver 13 has a photoelectric conversion function, which absorbs light incident from the second surface 11S2 side of the semiconductor layer 11 and generates charge carriers corresponding to the amount of light received. As described above, the light receiver 13 is configured to include an n-type semiconductor region (n) 111 in which the impurity concentration is controlled to be n-type, and the charge carriers (e.g., electrons) generated in the light receiver 13 are transported to the multiplier 14 by means of a potential gradient.

[0027] The multiplier 14 performs avalanche multiplication on the charge carriers (electrons) generated in the photoreceiver 13. For example, the multiplier 14 is formed by a p-type semiconductor region (p0) with a higher impurity concentration than the p-well (p0). + )14X and n-type semiconductor regions (n) with higher impurity concentrations than n-type semiconductor regions (n)111. + )14Y constitutes. p-type semiconductor region (p + ) 14X and n-type semiconductor regions (n +)14Y is disposed on the first surface 11S1 side, and extends from the first surface 11S1 side according to the n-type semiconductor region (n + )14Y and p-type semiconductor regions (p + The 14X layers are stacked in sequence. The p-type semiconductor region (p...) + The area of ​​14X in the XY plane is larger than that of the n-type semiconductor region (n + The area of ​​14Y in the XY plane, and for example, the p-type semiconductor region (p + ) 14X is configured to cover the entire surface of the unit pixel P divided by the pixel separation section 17. However, this is not limiting, and for example, as Figure 5 As shown, the p-type semiconductor region (p + )14X can be formed inside the p-type semiconductor region (p)112.

[0028] In the light-receiving element 12, the avalanche multiplication region 12X is formed in the p-type semiconductor region (p + ) 14X and n-type semiconductor regions (n + The junction between 14Y and 12X. The avalanche multiplication region 12X is formed in the p-type semiconductor region by applying a large negative voltage to the cathode. + ) 14X and n-type semiconductor regions (n + A high electric field region (depletion layer) is formed at the interface between 14Y and 14Y. In the avalanche multiplication region 12X, electrons (electrons) generated by a photon incident on the light-receiving element 12... - () was multiplied.

[0029] On the first surface 11S1 of the semiconductor layer 11, a contact layer 15 and a contact layer 16 are further provided. The contact layer 15 is composed of a p-type semiconductor region (p) electrically connected to the n-type semiconductor region (n) 111 used to constitute the light receiving section 13. ++ The contact layer 16 is composed of n-type semiconductor regions (n) used to form the multiplier section 14. + )14Y electrically connected n-type semiconductor region (n ++ For example, the contact layer 15 is configured to surround the light receiving portion 13 along the pixel separation portion 17. For example, the contact layer 16 is formed approximately at the center of the unit pixel P.

[0030] The pixel separation section 17 electrically separates adjacent unit pixels P from each other. For example, the pixel separation section 17 is arranged in a grid pattern in the pixel array section in a planar view to separate each of the multiple unit pixels P. The pixel separation section 17 extends between the first surface 11S1 and the second surface 11S2 of the semiconductor layer 11, and for example, penetrates the semiconductor layer 11. For example, the pixel separation section 17 is composed of an insulating film 17A and a light-shielding film 17B embedded in the insulating film 17A. The pixel separation section 17 can be provided from the first surface 11S1 side of the semiconductor layer 11, or it can be formed from the second surface 11S2 side of the semiconductor layer 11. The pixel separation section 17 can also serve as a through electrode for transferring charge carriers (e.g., electrons) generated in the photoelectric conversion layer 44 provided on the second surface 11S2 side of the semiconductor layer 11 to the readout circuit 210 provided on the first surface 11S1 side of the semiconductor layer 11.

[0031] For example, insulating film 17A is made by using silicon oxide (SiO2). x It is formed by, etc.

[0032] For example, the light-shielding film 17B is formed using a conductive material with light-shielding properties. Examples of conductive materials with light-shielding properties include metals such as tungsten (W), aluminum (Al), copper (Cu), cobalt (Co), nickel (Ni), or titanium (Ti), or their silicon compounds. Alternatively, the light-shielding film 17B can be formed using polycrystalline silicon (Poly-Si). The light-shielding film 17B may have an extension formed on the second surface 11S2 of the semiconductor layer 11, which is used to suppress the incidence of oblique incident light between adjacent unit pixels P, or to connect to a via (vertical interconnect channel) that electrically connects the photoelectric conversion layer 44 and the light-shielding film 17B.

[0033] For example, a layer with a fixed charge (fixed charge film 18) may be provided on the side and bottom surfaces of the pixel separation section 17 and on the second surface 11S2 of the semiconductor layer 11. The fixed charge film 18 may be a film with a positive fixed charge or a film with a negative fixed charge.

[0034] As the constituent material of the fixed charge film 18, a semiconductor material or conductive material having a wider band gap than that of the semiconductor layer 11 is preferably used. This suppresses the generation of dark current at the interface of the semiconductor layer 11. Examples of constituent materials for the fixed charge film 18 include hafnium oxide (HfO). x ), aluminum oxide (AlO) x Zirconium oxide (ZrO) x ), tantalum oxide (TaO) x Titanium oxide (TiO) xlanthanum oxide (LaO) x ), praseodymium oxide (PrO) x ), cerium oxide (CeO) x ), neodymium oxide (NdO) x ), Promethium oxide (PmO) x ), samarium oxide (SmO) x europium oxide (EuO) x ), gadolinium oxide (GdO) x ), terbium oxide (TbO) x ), Dysprosium oxide (DyO) x ), holmium oxide (HoO) x Thulium oxide (TmO) x ), Ytterbium oxide (YbO) x ), Lutene oxide (LuO) x ), Yttrium oxide (YO) x ), Hafnium nitride (HfN) x Aluminum nitride (AlN) x Hafnium oxide (HfO) x N y ) and aluminum oxynitride (AlO) x N y ).

[0035] For example, the readout circuit substrate 20 includes: a semiconductor layer 21 formed of a Si substrate; and an interlayer insulating layer 221 in which the semiconductor layer 21 is embedded. As described above, a plurality of transistors (e.g., pMOS transistor 211 and nMOS transistor 212) for constituting a readout circuit 210 are formed in the semiconductor layer 21, which outputs a pixel signal based on carriers from a unit pixel P, for example, a phase difference pixel output. Within the interlayer insulating layer 221, one or more wiring layers 222, 223, and 224 are provided on the surface 21S1 side of the semiconductor layer 21. For example, one or more wiring layers 222, 223, 224 include wiring for providing voltages applied to SPAD pixels and phase difference pixels and for extracting carriers generated in SPAD pixels and phase difference pixels. Furthermore, one or more wiring layers 222, 223, 224 are electrically connected to contact layers 15, 16, and the light-shielding film 17B respectively via through-paths V1a, V1b, and V1c penetrating the semiconductor layer 21 in the stacking direction (Z-axis direction). For example, one or more wiring layers 222, 223, 224 also include wiring for providing voltages applied to the semiconductor layer 21 and one or more pMOS transistors 211 and one or more nMOS transistors 212. Furthermore, for example, one or more wiring layers 222, 223, 224 are electrically connected to the gate electrode, source region, drain region, and well contact region (not shown) of each of the plurality of pMOS transistors 211 and the plurality of nMOS transistors 212 via vias V2 and V3. Multiple pads 225 for electrically connecting the readout circuit board 20 and the logic board 50 to each other are further embedded in the surface of the interlayer insulating layer 221.

[0036] For example, the semiconductor layer 21 is separated into multiple islands, and an insulating layer serving as a component separation portion is buried between the separated island semiconductor layers 21. For example, on the front side (surface 21S1) of each of the separated island semiconductor layers 21, multiple transistors for constituting a readout circuit 210 are formed, which outputs a pixel signal based on carriers output from the photoelectric conversion layer 44. Specifically, for example, one or more pMOS transistors 211 and one or more nMOS transistors 212 are formed. For example, the pMOS transistor 211 has a planar structure and includes a gate electrode and a p-type semiconductor region (p + The source and drain regions are formed by n-type semiconductor regions. For example, the nMOS transistor 212 has a planar structure and includes a gate electrode and a source and drain region formed by n-type semiconductor regions. + The source and drain regions are formed by the pMOS transistor 211 and the nMOS transistor 212. Although not shown, the semiconductor layer 21 in which the pMOS transistor 211 and the nMOS transistor 212 are formed has n-type semiconductor regions (n...) +) or p-type semiconductor region (p + The well contact region is formed by applying a predetermined potential to the semiconductor layer 21.

[0037] For example, the interlayer insulating layer 221 is composed of a single-layer film or a stacked film, wherein the single-layer film is made of silicon oxide (SiO2). x TEOS, silicon nitride (SiN) x ) and silicon oxynitride (SiO) x N y The laminated film is formed from one or more of the following:

[0038] For example, the gate electrodes of one or more pMOS transistors 211 and one or more nMOS transistors 212, as well as the wiring layers 222, 223, 224, are formed using aluminum (Al), copper (Cu), or tungsten (W).

[0039] For example, through-paths V1a, V1b, V1c and through-paths V2, V3 are formed by using light-shielding metallic materials such as tungsten (W), aluminum (Al), copper (Cu), cobalt (Co), nickel (Ni) or titanium (Ti) or their silicon compounds.

[0040] For example, the pad portion 229 is formed by using copper (Cu).

[0041] For example, the logic substrate 50 includes a semiconductor substrate 51 formed from a Si substrate and includes a multilayer wiring layer 52. The multilayer wiring layer 52 includes an interlayer insulating layer 521, and within the interlayer insulating layer 521, gate electrodes 522 of a plurality of transistors formed on the surface 51S1 of the semiconductor substrate 51 are formed, and one or more wiring layers are formed, and a plurality of pad portions 523 are buried in the surface of the interlayer insulating layer 521 facing the readout circuit substrate 20. As described above, logic circuits are formed in the logic substrate 50, for example, the logic circuits include a pixel front-end (PFE) circuit 511, a vertical drive circuit 512, an analog-to-digital converter circuit 513, a photon counting readout circuit 514, and an output circuit 515, etc.

[0042] For example, similar to interlayer insulating layer 221, interlayer insulating layer 521 is composed of a single-layer film or a stacked film, wherein the single-layer film is made of a material selected from SiO2. x TEOS, SiN x and SiO x N y One of the formations, wherein the laminated film is formed from two or more selected from there.

[0043] For example, similar to wiring layers 222, 223, 224, gate electrode 522 and one or more wiring layers are formed by using Al, Cu or W.

[0044] For example, similar to pad portion 229, pad portion 523 is formed by using Cu.

[0045] In the photodetector 1, a hybrid bonding (e.g., Cu-Cu bonding) is performed between the pad portion 229 and the pad portion 523. This enables the readout circuit board 20 and the logic board 50 to be electrically connected to each other.

[0046] On the back side of the sensor substrate 10, as described above, a photoelectric conversion layer 44, a protective layer 61, and an on-chip lens 62 are sequentially stacked across an interlayer insulating layer 41 containing a color filter 42. Within the interlayer insulating layer 41, in addition to the color filter 42, one or more wiring layers 432, 432 are also provided. For example, one or more wiring layers 432, 432 include wiring for providing a voltage applied to the photoelectric conversion layer 44 for forming a phase difference pixel and for extracting carriers generated in the photoelectric conversion layer 44. Furthermore, one or more wiring layers 431, 432 are electrically connected via a passage V4 to a light-shielding film 17B, which also serves as a through electrode.

[0047] For example, similar to interlayer insulating layers 221 and 521, interlayer insulating layer 41 is composed of a single-layer film or a stacked film, wherein the single-layer film is made of a material selected from SiO2. x TEOS, SiN x and SiO x N y One of the formations, wherein the laminated film is formed from two or more selected from there.

[0048] Color filters 42 selectively transmit light of a predetermined wavelength. For example, each unit pixel P may have a red filter that selectively transmits red light (R), a green filter that selectively transmits green light (G), or a blue filter that selectively transmits blue light (B). In a pixel array where multiple unit pixels P are arranged in an array along the row and column directions, for example, for four unit pixels P arranged in a 2x2 column configuration, two color filters that selectively transmit green light (G) are provided on one diagonal, and one color filter that selectively transmits red light (R) and one color filter that selectively transmits blue light (B) are provided on the diagonal perpendicular to it. Furthermore, in each SPAD pixel provided with color filters 42 of various colors, for example, the corresponding color light is detected in each light receiving element 12. In other words, in the pixel array section, the red pixel Pr for detecting red light (R), the green pixel Pg for detecting green light (G), and the blue pixel Pb for detecting blue light (B) are arranged in a Bayer pattern (for example, see...). Figure 4 ).

[0049] For example, wiring layers 432, 432 are formed using a transparent conductive material. Examples of transparent conductive materials include indium tin oxide (ITO), which is In2O3 with tin (Sn) added as a dopant.

[0050] For example, pathway V4 is formed by using a light-shielding metallic material such as W, Al, Cu, Co, Ni, or Ti, or its silicon compound.

[0051] The photoelectric conversion layer 44 selectively absorbs light in a predetermined wavelength band and performs charge separation. The photoelectric conversion layer 44 is configured to absorb some or all wavelengths in a band different from that absorbed by the light receiving element 12, such as the near-infrared band, and transmit wavelengths in other bands.

[0052] As described above, in the light detection device 1 of this embodiment, the photoelectric conversion layer 44 is used to form a phase difference pixel. As described above, the area of ​​the photoelectric conversion layer 44 in the plan view is smaller than the area of ​​the light receiving portion 13 of the light receiving element 12, and for example, the photoelectric conversion layer 44 is provided with a pitch of half (a / 2) of the pitch (a) of the SPAD pixel. That is, as... Figure 2 As shown, for example, four phase difference pixels P1, P2, P3, and P4 are provided on a single SPAD pixel (unit pixel P). A voltage is applied to each photoelectric conversion layer 44 provided in the phase difference pixels P1, P2, P3, and P4 respectively, thereby enabling each photoelectric conversion layer 44 to be driven independently.

[0053] For example, the photoelectric conversion layer 44 is an organic photoelectric conversion layer containing two or more organic materials that function as p-type semiconductors or n-type semiconductors, and has a junction surface (p / n junction surface) between p-type semiconductors and n-type semiconductors within the layer. Alternatively, the photoelectric conversion layer 44 may have a stacked structure of a layer formed of p-type semiconductors (p-type semiconductor layer) and a layer formed of n-type semiconductors (n-type semiconductor layer) (p-type semiconductor layer / n-type semiconductor layer), a stacked structure of a p-type semiconductor layer and a mixed layer of p-type and n-type semiconductors (bulk hetero layer) (p-type semiconductor layer / bulk hetero layer), or a stacked structure of an n-type semiconductor and a bulk hetero layer (n-type semiconductor layer / bulk hetero layer). The photoelectric conversion layer 44 may also be formed solely of a mixed layer of p-type and n-type semiconductors (bulk hetero layer).

[0054] The protective layer 61 protects the photoelectric conversion layer 44 and flattens the surface of the sensor substrate 10 on the light incident side, where the interlayer insulating layer 41 and the photoelectric conversion layer 44 are provided. The protective layer 61 is made of a light-transmitting material, for example, a single-layer film formed of any one of silicon oxide, silicon nitride, and silicon oxynitride, or a laminated film formed of two or more of them.

[0055] The on-chip lens 62 is used to focus light incident from above onto the light-receiving element 12, and, for example, by using SiO2. x And thus formed. For example, the on-chip lens 62 is set at the same pitch (a) as the SPAD pixel pitch, i.e., as... Figure 1 As shown, it is set for each unit pixel P. In other words, the on-chip lens 62 is set at a pitch of half (a / 2) with respect to the photoelectric conversion layer 44 that constitutes the phase difference pixel.

[0056] [Layout of phase difference pixels] Figures 4 to 8 An example of a planar layout of phase difference pixels in a pixel array section is schematically shown, in which multiple unit pixels P are arranged in an array along the row and column directions.

[0057] For example, such as Figure 4 As shown, the photoelectric conversion layer 44 can be disposed on all SPAD pixels in both the row direction (X-axis direction) and column direction (Y-axis direction) at half the pitch of the SPAD pixels, thereby providing four phase difference pixels P1, P2, P3, and P4 for each SPAD pixel. In this configuration, autofocus can be performed in all unit pixels P. Furthermore, in this configuration, vertical and horizontal separation can be selected in any unit pixel P, thus achieving high autofocus accuracy.

[0058] For example, such as Figure 5 As shown, the photoelectric conversion layer 44 can be disposed on all SPAD pixels in the row direction (X-axis direction) or column direction (Y-axis direction) at half the pitch of the SPAD pixels, thereby setting two phase difference pixels P1 and P2 for each SPAD pixel. In this configuration, autofocus can be performed in all unit pixels P. In this configuration, vertical and horizontal information will use information from different unit pixels P respectively, thus... Figure 4 Compared to the previous layout, the autofocus accuracy is reduced, but the number of phase difference pixels is also reduced, making control easier and improving readout speed. In addition, the number of wiring and transistors is also reduced.

[0059] For example, such as Figure 6As shown, the photoelectric conversion layer 44 can be disposed on only half of the vertical or horizontal direction of all SPAD pixels, thereby arranging a phase difference pixel P1 for each SPAD pixel. In this configuration, autofocus is possible in all unit pixels P. In this configuration, as shown... Figure 4 and Figure 5 Compared to the case where the photoelectric conversion layer 44 is provided on all SPAD pixels, the reduction in SPAD pixel sensitivity caused by absorption by the photoelectric conversion layer 44 can be suppressed. In this configuration, vertical and horizontal information will use information from different unit pixels P, thus... Figure 4 Compared to the previous layout, the autofocus accuracy will be lower, but compared to Figure 5 Compared to the previous layout, the number of phase difference pixels is further reduced, making control easier and improving readout speed. Furthermore, the number of wiring and transistors is also reduced.

[0060] For example, such as Figure 7 As shown, phase difference pixels can be arranged only on specific SPAD pixels. Specifically, phase difference pixels can be arranged only on the green pixel Pg. On the green pixel Pg, as... Figure 7 As shown, two phase-difference pixels P1 and P2, set at half the pitch of the SPAD pixels, can be arranged in the row direction (X-axis direction) or column direction (Y-axis direction). Alternatively, as... Figure 4 As shown, four phase difference pixels P1, P2, P3, and P4, set according to half the pitch of the SPAD pixels, can be arranged in both the row direction (X-axis direction) and column direction (Y-axis direction), or as shown in the diagram. Figure 6 As shown, a phase difference pixel P1 can be arranged only on half of the vertical or horizontal axis of the PAD pixels. In this configuration, while autofocus cannot be performed on all unit pixels P, it can be performed at almost all viewing angles. Furthermore, in this configuration, the reduction in sensitivity can be suppressed, especially in the red pixel Pr and blue pixel Pb, where sensitivity is particularly low.

[0061] For example, such as Figure 8 As shown, phase difference pixels can be set only on some SPAD pixels among the multiple unit pixels P used to form the pixel array section. The phase difference pixel layout on the SPAD pixels can be as follows: Figure 8 As shown, there are two phase difference pixels P1 and P2 in the row direction (X-axis direction) or column direction (Y-axis direction), set according to half the pitch of the SPAD pixels, or as shown in the diagram. Figure 4 As shown, it has four phase difference pixels P1, P2, P3, and P4 arranged in a 2x2 grid, or it can be arranged as follows: Figure 6As shown, there is only one phase difference pixel P1 on either the vertical or horizontal half of the PAD pixel. In this configuration, although autofocus cannot be performed in all unit pixels P, the sensitivity reduction of the SPAD pixel due to absorption by the photoelectric conversion layer 44 can be significantly suppressed.

[0062] [Readout Processing of the Optical Detection Device] Figure 9 An example of the processing flow of the light detection device 1 during readout is shown. As described above, the light detection device 1 of this embodiment has a readout circuit (photon counting circuit) for acquiring pixel signals from SPAD pixels and a readout circuit (analog-to-digital conversion circuit) for acquiring pixel information from phase difference pixels, serving as the readout circuit. This enables simultaneous exposure and phase difference acquisition.

[0063] In the light detection device 1, when the exposure frame begins, a reset operation is first performed in both the light receiving element 12 and the photoelectric conversion layer 44 (step S101). After the reset operation is completed, exposure begins, and carriers generated by photoelectric conversion are accumulated in both the light receiving element 12 and the photoelectric conversion layer 44 (step S102). Subsequently, carrier readout is performed in the SPAD pixel (step S103), and the pixel signal generated in the photon counting circuit is output to the interface I / F (step S104). Furthermore, the readout processing in the phase difference pixel is performed in parallel with the readout processing in the SPAD pixel. First, carrier readout is performed in the phase difference pixel P1 (step S105), and the pixel signal generated in the analog-to-digital conversion circuit is output to the interface I / F (step S106). Next, carrier readout is performed in the phase difference pixel P2 (step S107), and the pixel signal generated in the analog-to-digital conversion circuit is output to the interface I / F (step S108), thus ending the exposure frame.

[0064] [Functions and Effects] The light detection device 1 of this embodiment includes a photoelectric conversion layer 44, which is located between a semiconductor layer 11 having SPAD elements as light receiving elements 12 for each unit pixel P and an on-chip lens 62 for each unit pixel P. The area of ​​the photoelectric conversion layer 44 in the plan view is smaller than the area of ​​the light receiving portion 13 of the light receiving element 12. Therefore, while suppressing the decrease in sensitivity of the light receiving element 12, the separation ratio of the photoelectric conversion layer 44 is ensured. This will be explained below.

[0065] As mentioned earlier, in photon counting camera sensors using single-photon avalanche diodes (SPADs), there is a technique for acquiring phase difference information by setting an on-chip lens spanning multiple pixels. However, in typical SPAD pixels without inter-pixel light-shielding walls between phase difference pixels, color mixing due to emission during doubling is significant, and the separation ratio between phase difference pixels decreases. While setting inter-pixel light-shielding walls between phase difference pixels can ensure the separation ratio, light absorption at these walls leads to reduced sensitivity. In particular, when an on-chip lens spanning multiple pixels is used, these inter-pixel light-shielding walls are formed at the central portion of the lens, i.e., the light convergence point, thus amplifying the sensitivity reduction. Appropriate design structures can be considered to balance the separation ratio between phase difference pixels and the suppression of sensitivity reduction, but this increases structural complexity and cost.

[0066] In contrast, this embodiment includes a photoelectric conversion layer 44, which is located, for example, between a semiconductor layer 11 having SPAD elements (light receiving elements 12) for each unit pixel P and an on-chip lens 62 for each unit pixel P. The area of ​​the photoelectric conversion layer 44 in the plan view is smaller than the area of ​​the light receiving portion 13 of the light receiving element 12, and phase difference information is obtained from this photoelectric conversion layer 44. Therefore, compared to the photon counting camera sensor described above, while suppressing the decrease in sensitivity of the light receiving element 12 (SPAD pixel), the separation ratio of the photoelectric conversion layer 44 (phase difference pixel) can be ensured.

[0067] As mentioned above, the light detection device 1 of this embodiment can improve imaging characteristics. Specifically, the light detection device 1 of this embodiment can improve autofocus accuracy.

[0068] Furthermore, compared to cases with complex pixel separation structures, the light detection device 1 of this embodiment can achieve both a good separation ratio between phase difference pixels and suppression of sensitivity reduction with a simpler structure and lower cost.

[0069] Furthermore, in the light detection device 1 of this embodiment, by adding the near-infrared information obtained from the phase difference pixel during imaging to the visible light information of the SPAD pixel, the resolution and the S / N ratio (signal-to-noise ratio) under low illumination conditions can be improved.

[0070] Next, the second embodiment, variation 1 and variation 2, as well as applicable and application examples of this disclosure will be described. In the following, the same constituent elements as those in the above embodiments are given the same reference numerals, and their descriptions are appropriately omitted.

[0071] <2. Variations> (2-1. Variation Example 1) Figure 10 This is a block diagram illustrating a schematic structure of a light detection device (light detection device 1A) according to a variation of this disclosure.

[0072] In the first embodiment described above, an example is shown in which the vertical drive circuit 512 and the analog-to-digital converter circuit 513 are disposed on the logic substrate 50, but this is not limiting. In the light detection device 1A of this variant, a portion of the vertical drive circuit 512 and the analog-to-digital converter circuit 513 are disposed together with the readout circuit 210 in the semiconductor layer 21.

[0073] This results in the optical detection device 1A of this variant having a smaller chip size compared to the optical detection device 1 of the first embodiment described above.

[0074] Note that part of the analog-to-digital conversion circuit 513, which serves as the readout circuit for the phase difference pixels, can be disposed in the semiconductor layer 21. In this way, by appropriately disposing of the circuitry located at the periphery of the pixel array portion in the logic substrate 50 into the semiconductor layer 21, the chip size can be reduced.

[0075] (2-2. Variation Example 2) Figure 11 An example of the processing flow of the optical detection device according to a variation of this disclosure 2 during readout is shown.

[0076] In the light detection device 1 described in the first embodiment above, since the SPAD pixels and the phase difference pixels differ in height relative to the incident direction of light L, their focal distances are different. Therefore, when focusing on the phase difference pixel, a shift may occur on the SPAD pixel. In this modified example, for example, after obtaining pixel information from the phase difference pixel, a process for correcting the focal deviation caused by the height difference between the SPAD pixels and the phase difference pixel (focal shift correction) is performed.

[0077] In this modified example, when the exposure frame begins, firstly, as in the first embodiment described above, a reset operation is performed in both the light receiving element 12 and the photoelectric conversion layer 44. After the reset operation is completed, exposure begins, and carriers generated by photoelectric conversion are accumulated in both the light receiving element 12 and the photoelectric conversion layer 44 (step S201). Subsequently, carrier readout is performed in the SPAD pixels, and a pixel signal generated in the photon counting circuit is produced (step S202). Then, the obtained pixel signal is output as image information (step S203). Furthermore, in parallel with the readout processing in the SPAD pixels, readout processing is performed in the phase difference pixels P1 and P2 (steps S212, S213). Next, after performing focus calculation (step S214), focus shift correction is performed based on the obtained result (step S215). Afterward, autofocus (AF) driving is performed (step S216), and the processing moves to the next frame.

[0078] In this modified example, after obtaining pixel information from the phase difference pixels, a process (focus shift correction) is performed to correct focus deviation caused by the height difference between the SPAD pixels and the phase difference pixels. This further improves the imaging characteristics.

[0079] <3. Second Implementation Plan> Figure 12 An example of the cross-sectional structure of a light detection device (light detection device 2) according to a second embodiment of the present disclosure is schematically shown. For example, the light detection device 2 is applied to image sensors such as digital cameras and camcorders, as well as distance image sensors that perform distance measurements using the Time-of-Flight (ToF) method.

[0080] The light detection device 2 has a light receiving element 12 provided for each unit pixel P. The light receiving element 12 has a light receiving portion 13 and a multiplying portion 14, and is disposed in a semiconductor layer 11. The semiconductor layer 11 has a first surface 11S1 and a second surface 11S2 that are opposite to each other. On the second surface 11S2 side, which serves as the light incident surface, an on-chip lens 62 is provided for each unit pixel P. In the light detection device 2 of this embodiment, a sensor substrate 70 is disposed between the second surface 11S2 of the semiconductor layer 11 and the on-chip lens 62. The sensor substrate 70 includes a semiconductor layer 71, which has a third surface 71S1 and a fourth surface 71S2 that are opposite to each other, and a photodiode (PD) 73 is embedded in the semiconductor layer 71. In a plan view, the area of ​​the photodiode (PD) 73 is smaller than the area of ​​the light receiving portion 13 of the light receiving element 12.

[0081] Here, semiconductor layer 71 corresponds to a specific example of the "third semiconductor layer" in the second embodiment of this disclosure, and PD 73 corresponds to a specific example of the "photoelectric conversion layer" in the second embodiment of this disclosure.

[0082] For example, the sensor substrate 70 has: a semiconductor layer 71 formed of a Si substrate; and a multilayer wiring layer 75 disposed on the third surface 71S1 side of the semiconductor layer 71. The semiconductor layer 71 has: a p-well 72 located in a predetermined region; a PD 73 for non-multiplicatively accumulating charge carriers (e.g., electrons) generated by photoelectric conversion; and a separation portion 74 separating adjacent PDs from each other. On the third surface of the semiconductor layer 71, for example, a transfer transistor for reading out the charge carriers generated and accumulated in the PD 73 is disposed. The multilayer wiring layer 75 includes an interlayer insulating layer 751, and within the interlayer insulating layer 751, a gate electrode 752 of the transfer transistor and one or more wiring layers 753 are formed, the one or more wiring layers 753 including wiring for transferring the charge carriers read out by the transfer transistor to the readout circuit 210. A plurality of pad portions 754 are buried in the surface of the interlayer insulating layer 751.

[0083] In the interlayer insulating layer 41 disposed on the back side of the sensor substrate 10, in addition to a color filter 42 and one or more wiring layers 432, an infrared cut-off filter 45 is also disposed, for example. A plurality of pads 433 are embedded in the surface of the interlayer insulating layer 41.

[0084] In the photodetector 2, a hybrid bonding (e.g., Cu-Cu bonding) is performed between the pad portion 433 and the pad portion 754. This enables the sensor substrate 10 and the sensor substrate 70 to be electrically connected to each other.

[0085] In this manner, the light detection device 2 of this embodiment includes a sensor substrate 70 located between a semiconductor layer 11 having SPAD elements (light receiving elements 12) provided for each unit pixel P and an on-chip lens 62 provided for each unit pixel P. The sensor substrate 70 includes a semiconductor layer 71 having a third surface 71S1 and a fourth surface 71S2 opposite to each other, and a PD 73 is embedded in the semiconductor layer 71. The area of ​​the PD 73 in the plan view is smaller than the area of ​​the light receiving portion 13 of the light receiving element 12, and phase difference information is obtained from the PD 73. In this way, while suppressing the decrease in sensitivity of the light receiving element 12 (SPAD pixel), the separation ratio of the PD 73 (phase difference pixel) can be ensured.

[0086] As mentioned above, similar to the first embodiment described above, the light detection device 2 in this embodiment can improve the imaging characteristics.

[0087] <4. Applicable Examples> (Applicable Example 1) The light detection device (e.g., light detection device 1) according to the first and second embodiments described above, as well as modifications 1 and 2, can be applied to various electronic devices such as camera systems like digital cameras and digital camcorders; mobile phones equipped with camera functions; or other devices equipped with camera functions.

[0088] Figure 13 This is a block diagram illustrating a construction example of an electronic device 1000.

[0089] like Figure 13 As shown, the electronic device 1000 includes an optical system 1001, a light detection device 1, and a digital signal processor (DSP) 1002. The electronic device 1000 is equipped with a DSP 1002, a memory 1003, a display device 1004, a recording device 1005, an operating system 1006, and a power supply system 1007, which are interconnected via a bus 1008, and is capable of capturing still images and moving images.

[0090] The optical system 1001 is provided with one or more lenses and captures incident light (image light) from the subject, thereby forming an image on the imaging surface of the light detection device 1.

[0091] The light detection device 1 converts the amount of incident light imaged on the imaging surface by the optical system 1001 into an electrical signal in units of pixels, and provides the electrical signal as a pixel signal to the DSP 1002.

[0092] The DSP 1002 performs various signal processing operations on the signals from the photodetector 1 to acquire images, and temporarily stores the image data in the memory 1003. The image data stored in the memory 1003 is recorded in the recording device 1005 or provided to the display device 1004 to display the images. In addition, the operating system 1006 accepts various operations from the user and provides operation signals to the various blocks of the electronic device 1000, and the power supply system 1007 provides the power required to drive the various blocks of the electronic device 1000.

[0093] (Applicable Example 2) Figure 14A An example of the overall structure of a light detection system 2000 equipped with a light detection device 1 is shown schematically. Figure 14BAn example of the circuit structure of the light detection system 2000 is shown. The light detection system 2000 includes: a light-emitting device 2001 as a light source for emitting infrared light L2; and a light detection device 2002 as a light receiving device having a photoelectric conversion element. The light detection device 1 described above can be used as the light detection device 2002. The light detection system 2000 may also include a system control unit 2003, a light source driving unit 2004, a sensor control unit 2005, a light source-side optical system 2006, and a camera-side optical system 2007.

[0094] The light detection device 2002 can detect light L1 and light L2. Light L1 is ambient light from the external source, detected by the subject (the object being measured) 2100 ( Figure 14A Light L1 is the light emitted by the light-emitting device 2001 and then reflected by the subject 2100. For example, light L1 is visible light, and light L2 is infrared light. Light L1 can be detected in the photoelectric conversion section of the light detection device 2002, and light L2 can be detected in the photoelectric conversion area of ​​the light detection device 2002. Image information of the subject 2100 can be obtained from light L1, and distance information between the subject 2100 and the light detection system 2000 can be obtained from light L2. For example, the light detection system 2000 can be installed on electronic devices such as smartphones or mobile bodies such as automobiles. For example, the light-emitting device 2001 can be equipped with a semiconductor laser, a surface-emitting semiconductor laser, or a vertical cavity surface-emitting laser (VCSEL). As a method for detecting light L2 emitted from the light-emitting device 2001 using the light detection device 2002, for example, the iTOF (indirect TOF) method can be used, but it is not limited to this. In the iTOF method, for example, the photoelectric conversion unit can measure the distance to the subject 2100 using time-of-flight (TOF). As a method for detecting light L2 emitted from the light-emitting device 2001 using the light detection device 2002, structured light or stereoscopic vision methods can also be employed, for example. For example, in the structured light method, light of a predetermined pattern is projected onto the subject 2100, and the distance between the light detection system 2000 and the subject 2100 can be measured by analyzing the degree of distortion of the pattern. Furthermore, in the stereoscopic vision method, for example, two or more cameras are used, and the distance between the light detection system 2000 and the subject can be measured by acquiring two or more images of the subject 2100 observed from two or more different viewpoints. Note that the light-emitting device 2001 and the light detection device 2002 can be synchronously controlled by the system control unit 2003.

[0095] (Applicable Example 3) Figure 15An example of a schematic construction of a distance imaging device 3000 is shown, which is an electronic device equipped with a light detection device (e.g., light detection device 1) according to the first and second embodiments described above, as well as modifications 1 and 2.

[0096] For example, the distance imaging device 3000 includes a light source device 3100, an optical system 3200, a light detection device 1, an image processing circuit 3300, a monitor 3400, and a memory 3500.

[0097] The distance imaging device 3000 can acquire a distance image corresponding to the distance to the irradiated object 4000 by projecting light from the light source device 3100 toward the irradiated object 4000 and receiving light (modulated light or pulsed light) reflected from the surface of the irradiated object 4000.

[0098] The optical system 3200 is provided with one or more lenses and guides the image light (incident light) from the irradiated object 4000 to the light detection device 1, thereby forming an image on the light receiving surface (sensor section) of the light detection device 1.

[0099] The image processing circuit 3300 performs image processing to construct a distance image based on the distance signal provided from the light detection device 1, and the distance image (image data) obtained by the image processing is provided to the monitor 3400 for display or to the memory 3500 for storage (recording).

[0100] In the distance imaging device 3000 constructed in this way, by applying the aforementioned light detection device (e.g., light detection device 1), the distance to the illuminated object 4000 can be calculated solely based on the highly stable light received signal from the unit pixel P, and a high-precision distance image can be generated. In other words, the distance imaging device 3000 can acquire a more accurate distance image.

[0101] <5. Application Examples> (Examples of the application of endoscopic surgical systems) The technology disclosed herein (the Technology) can be applied to a variety of products. For example, the Technology disclosed herein can be applied to endoscopic surgical systems.

[0102] Figure 16 This is a diagram illustrating an example of a schematic construction of an endoscopic surgical system applicable to the technology (the present technology) according to this disclosure.

[0103] exist Figure 16The figure illustrates a surgeon (physician) 11131 performing surgery on a patient 11132 on a bed 11133 using an endoscopic surgical system 11000. As shown in the figure, the endoscopic surgical system 11000 includes: an endoscope 11100; other surgical instruments 11110 such as a pneumoperitoneum tube 11111 and an energy delivery device 11112; a support arm device 11120 for supporting the endoscope 11100; and a trolley 11200 equipped with various devices for endoscopic surgery.

[0104] Endoscope 11100 includes: a tube 11101, a portion of which, measured from its tip, of a predetermined length, is inserted into a body cavity of patient 11132; and a camera head 11102, which is connected to the base of the tube 11101. In the example shown in the figure, endoscope 11100 is illustrated as a so-called rigid endoscope with a rigid tube 11101, but endoscope 11100 can also be configured as a so-called flexible endoscope with a flexible tube.

[0105] An opening is provided at the front end of the endoscope tube 11101, into which the objective lens is inserted. A light source device 11203 is connected to the endoscope 11100. Light generated by the light source device 11203 is guided to the front end of the endoscope tube by a light guide extending inside the endoscope tube 11101, and then irradiated towards the object of observation within the body cavity of the patient 11132 via the objective lens. Note that the endoscope 11100 can be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0106] An optical system and an image sensor are housed inside the camera head 11102. Reflected light from the object being observed (observation light) is converged onto the image sensor via the optical system. The image sensor performs photoelectric conversion on the observation light and generates an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. This image signal is transmitted as RAW (raw) data to the camera control unit (CCU) 11201.

[0107] The CCU 11201 includes a central processing unit (CPU) or a graphics processing unit (GPU), and comprehensively controls the operation of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives image signals from the camera head 11102 and performs various image processing operations on the image signals, such as image processing (de-mosaicing), to display an image based on the image signals.

[0108] Under the control of CCU 11201, display device 11202 displays an image based on the image signal that has been processed by CCU 11201.

[0109] For example, the light source device 11203 includes a light source such as a light emitting diode (LED) and supplies illumination light to the endoscope 11100 when imaging the surgical site, etc.

[0110] Input device 11204 is an input interface for endoscopic surgical system 11000. Users can input various information and commands into endoscopic surgical system 11000 through input device 11204. For example, users can input commands to change the imaging conditions of endoscope 11100 (type of illumination light, magnification, focal distance, etc.).

[0111] The treatment device control unit 11205 controls the actuation of the energy treatment device 11112 used for tissue cauterization, incision, or vascular closure. The pneumoperitoneum device 11206 delivers gas into the body cavity of the patient 11132 via the pneumoperitoneum tube 11111 to inflate the cavity, thereby ensuring the field of vision of the endoscope 11100 and ensuring the surgeon's working space. The recorder 11207 is a device capable of recording various information related to the surgery. The printer 11208 is a device capable of printing various information related to the surgery in various forms such as text, images, or charts.

[0112] Note that, for example, the light source device 11203 used to supply illumination light to the endoscope 11100 when imaging the surgical site may include an LED, a laser light source, or a white light source formed by a combination of the two. When the white light source is formed by a combination of red, green, and blue (RGB) laser light sources, the output intensity and timing of each color (wavelength) can be controlled with high precision, thus enabling white balance adjustment of the captured image via the light source device 11203. Furthermore, in this case, by illuminating the object of observation with lasers from each of the RGB laser light sources in a time-division manner, and controlling the driving of the imaging element of the camera head 11102 in sync with the illumination timing, images corresponding to each of the RGB light sources can be captured in a time-division manner. According to this method, color images can be obtained even when no color filter is provided on the imaging element.

[0113] Furthermore, the drive of the light source device 11203 can be controlled so that the intensity of the light to be output changes at predetermined intervals. By controlling the drive of the imaging element of the camera head 11102 in time sequence with the change in light intensity, images can be acquired and synthesized in a time-division manner, thereby generating high dynamic range images that do not suffer from underexposure or overexposure.

[0114] Furthermore, the light source device 11203 can be configured to provide light within a predetermined wavelength range corresponding to special light observation. In special light observation, for example, so-called narrowband imaging is performed by utilizing the wavelength dependence of light absorption in body tissues and irradiating light with a narrow band range compared to the irradiation light during ordinary observation (i.e., white light), thereby imaging predetermined tissues such as blood vessels in the mucosal surface with high contrast. Alternatively, in special light observation, fluorescence observation can be performed to obtain an image using fluorescence generated by irradiating excitation light. In this fluorescence observation, excitation light is irradiated onto body tissue and fluorescence from that body tissue is observed (autofluorescence observation), or a reagent such as indocyanine green (ICG) is locally injected into body tissue, and excitation light corresponding to the fluorescence wavelength of the reagent is irradiated onto the body tissue to obtain a fluorescence image. The light source device 11203 can be configured to provide narrowband light and / or excitation light corresponding to this special light observation.

[0115] Figure 17 It is shown Figure 16 A block diagram illustrating an example of the functional configuration of the camera head 11102 and CCU 11201.

[0116] Camera head 11102 includes a lens unit 11401, an image capturing unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. CCU 11201 includes a communication unit 11411, an image processing unit 11412, and a control unit 11413. Camera head 11102 and CCU 11201 are communicatively connected to each other via a transmission cable 11400.

[0117] The lens section 11401 is an optical system provided at the connection point with the lens barrel 11101. Observation light received from the front end of the lens barrel 11101 is guided to the camera head 11102 and introduced into the lens section 11401. The lens section 11401 is constructed by combining multiple lenses, including a zoom lens and a focusing lens.

[0118] The imaging unit 11402 may include one (so-called single-plate type) or multiple (so-called multi-plate type). When the imaging unit 11402 is configured as a multi-plate type, for example, each imaging element generates an image signal corresponding to each of the RGB values, and a color image can be obtained by combining these image signals. The imaging unit 11402 may also be configured to have a pair of imaging elements, which are used to acquire right-eye and left-eye image signals respectively for 3D (three-dimensional) display. By performing 3D display, the surgeon 11131 can more accurately grasp the depth of biological tissue in the surgical site. Note that when the imaging unit 11402 is configured as a multi-plate type, multiple lens units 11401 are provided corresponding to each imaging element.

[0119] Furthermore, the camera unit 11402 does not necessarily have to be located in the camera head 11102. For example, the camera unit 11402 can be located inside the lens barrel 11101 and immediately behind the objective lens.

[0120] The drive unit 11403 includes an actuator, and under the control of the camera head control unit 11405, moves the zoom lens and focusing lens of the lens unit 11401 a predetermined distance along the optical axis. This allows for appropriate adjustment of the magnification and focus of the image captured by the imaging unit 11402.

[0121] The communication unit 11404 includes communication devices for sending various information to and receiving various information from the CCU 11201. The communication unit 11404 transmits image signals acquired from the camera unit 11402 as RAW data to the CCU 11201 via the transmission cable 11400.

[0122] Furthermore, the communication unit 11404 receives control signals from the CCU 11201 for controlling the drive of the camera head 11102, and supplies these control signals to the camera head control unit 11405. For example, the control signals include information related to the shooting conditions, such as information for specifying the frame rate of the captured image; information for specifying the exposure value during shooting; and / or information for specifying the magnification and focus of the captured image.

[0123] Note that the aforementioned imaging conditions, such as frame rate, exposure value, magnification, and focus, can be appropriately specified by the user, or can be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with so-called automatic exposure (AE), automatic focus (AF), and automatic white balance (AWB) functions.

[0124] The camera head control unit 11405 controls the drive of the camera head 11102 based on the control signal received from the CCU 11201 via the communication unit 11404.

[0125] The communication unit 11411 includes a communication device for sending various information to and receiving various information from the camera head 11102. The communication unit 11411 receives image signals transmitted from the camera head 11102 via the transmission cable 11400.

[0126] In addition, the communication unit 11411 sends control signals for controlling the camera head 11102 to the camera head 11102. Image signals and control signals can be transmitted via electrical communication, optical communication, etc.

[0127] The image processing unit 11412 performs various image processing operations on the image signal transmitted from the camera head 11102 as RAW data.

[0128] The control unit 11413 performs various controls related to imaging the surgical site, etc., through the endoscope 11100 and displaying the captured images obtained by imaging the surgical site, etc. For example, the control unit 11413 generates control signals for controlling the drive of the camera head 11102.

[0129] Furthermore, based on the image signal that has already undergone image processing by the image processing unit 11412, the control unit 11413 causes the display device 11202 to display the captured image reflecting the surgical site, etc. At this time, the control unit 11413 can use various image recognition techniques to identify various objects within the captured image. For example, the control unit 11413 can identify surgical instruments such as forceps, specific biological sites, bleeding, and fogging when using the energy device 11112 by detecting the edge shape, color, etc., of objects contained in the captured image. When the control unit 11413 causes the display device 11202 to display the captured image, the control unit 11413 can overlay various surgical assistance information onto the image of the surgical site using the recognition results. By overlaying and displaying the surgical assistance information and providing it to the surgeon 11131, the workload of the surgeon 11131 can be reduced, and the surgeon 11131 can perform the surgery reliably.

[0130] The transmission cable 11400 that connects the camera head 11102 and CCU 11201 to each other is an electrical signal cable for electrical signal communication, an optical fiber for optical communication, or a composite cable thereof.

[0131] Here, in the illustrated example, communication is conducted via a wired connection using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 can be conducted wirelessly.

[0132] The examples of endoscopic surgical systems to which the technology according to this disclosure can be applied have been described above. The technology according to this disclosure can be applied to the imaging unit 11402 in the configuration described above. By applying the technology according to this disclosure to the imaging unit 11402, detection accuracy is improved.

[0133] Note that although the endoscopic surgical system is used as an example here, the technology disclosed herein can be applied to other systems such as microsurgical systems.

[0134] (Example of the application of moving objects) The technology disclosed herein can be applied to a variety of products. For example, the technology disclosed herein can be implemented as a device mounted on any type of mobile body such as automobiles, electric vehicles, hybrid vehicles, autonomous two-wheelers, bicycles, personal motor vehicles, airplanes, unmanned aerial vehicles, ships, robots, construction machinery, or agricultural machinery (tractors).

[0135] Figure 18 This is a block diagram illustrating a schematic construction example of a vehicle control system, which serves as an example of a mobile body control system to which the technology according to this disclosure can be applied.

[0136] The vehicle control system 12000 includes multiple electronic control units interconnected via a communication network 12001. Figure 18 In the example shown, 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 a comprehensive control unit 12050. Furthermore, as part of the functional configuration of the comprehensive control unit 12050, a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface (I / F) 12053 are shown.

[0137] The drive system control unit 12010 controls the operation of equipment related to the vehicle's drive system according to various programs. For example, the drive system control unit 12010 functions as a control device for various devices such as: a drive force generating device for generating vehicle driving force, such as an internal combustion engine or drive motor; a drive force transmission mechanism for transmitting driving force to the wheels; a steering mechanism for adjusting the vehicle's steering angle; and a braking device for generating vehicle braking force.

[0138] The body system control unit 12020 controls the operation of various devices equipped on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for various devices such as: keyless entry system; smart key system; power windows; or various lights such as headlights, reversing lights, brake lights, turn signals, or fog lights. In this case, radio waves emitted from a portable device that replaces the 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 signal inputs and controls the vehicle's door locking devices, power windows, lights, etc.

[0139] The exterior information detection unit 12030 detects external information of the vehicle equipped with the vehicle control system 12000. For example, a camera unit 12031 is connected to the exterior information detection unit 12030. The exterior information detection unit 12030 causes the camera unit 12031 to capture images of the exterior of the vehicle and receives the captured images. Based on the received images, the exterior information detection unit 12030 can perform object detection processing such as people, vehicles, obstacles, signs, and text on the road surface, or distance detection processing.

[0140] The camera unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The camera unit 12031 can output the electrical signal as an image or as ranging information. Furthermore, the light received by the camera unit 12031 can be visible light or non-visible light such as infrared light.

[0141] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 for detecting the driver's state is connected to the in-vehicle information detection unit 12040. For example, the driver state detection unit 12041 includes a camera that captures images of the driver, and based on the detection information input from the driver state detection unit 12041, the in-vehicle information detection unit 12040 can calculate the driver's fatigue level or the driver's concentration level, or it can determine whether the driver is dozing off.

[0142] Based on information about the exterior or interior of the vehicle acquired by the exterior information detection unit 12030 or the interior information detection unit 12040, the microcomputer 12051 can calculate target control values ​​for the drive force generating device, steering mechanism, or braking device, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform coordinated control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, distance-based following, constant speed control, collision warning, and lane departure warning.

[0143] Furthermore, based on information about the vehicle's surroundings obtained by the external information detection unit 12030 or the internal information detection unit 12040, the microcomputer 12051 can perform coordinated control, such as autonomous driving, which aims to enable the vehicle to drive autonomously without relying on the driver's operation, by controlling the drive force generating device, steering mechanism, braking device, etc.

[0144] Furthermore, based on the external information obtained by the external information detection unit 12030, the microcomputer 12051 can output control commands to the body system control unit 12020. For example, based on the position of the vehicle in front or oncoming vehicle detected by the external information detection unit 12030, the microcomputer 12051 can perform coordinated control aimed at achieving anti-glare, such as controlling the headlights to switch from high beam to low beam.

[0145] The sound / image output unit 12052 sends an output signal of at least one of sound and image to an output device capable of visually or audibly notifying vehicle occupants or external to the vehicle. Figure 18 In the example shown, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are shown as output devices. For example, the display unit 12062 may include at least one of an onboard display and a head-up display.

[0146] Figure 19 This is a diagram showing an example of the mounting position of the camera unit 12031.

[0147] exist Figure 19 In the middle, as a camera unit 12031, camera units 12101, 12102, 12103, 12104 and 12105 are provided.

[0148] For example, cameras 12101, 12102, 12103, 12104, and 12105 are installed at the front bumper, side mirrors, rear bumper, trunk lid, and the upper part of the windshield inside the vehicle 12100. Camera 12101 at the front bumper and camera 12105 at the upper part of the windshield inside the vehicle primarily acquire images of the front of the vehicle 12100. Cameras 12102 and 12103 at the side mirrors primarily acquire images of the sides of the vehicle 12100. Camera 12104 at the rear bumper or trunk lid primarily acquires images of the rear of the vehicle 12100. Camera 12105 at the upper part of the windshield inside the vehicle is mainly used to detect vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc., ahead.

[0149] Notice, Figure 19 An example of the camera range of camera units 12101 to 12104 is shown. Camera range 12111 represents the camera range of camera unit 12101 located at the front bumper, camera ranges 12112 and 12113 represent the camera ranges of camera units 12102 and 12103 located at the side mirrors, respectively, and camera range 12114 represents the camera range of camera unit 12104 located at the rear bumper or trunk lid. For example, by superimposing the image data captured by camera units 12101 to 12104, a top-down view of vehicle 12100 can be obtained.

[0150] At least one of the camera units 12101 to 12104 may have the function of acquiring distance information. For example, at least one of the camera units 12101 to 12104 may be a stereo camera composed of multiple camera elements or a camera element having pixels for phase difference detection.

[0151] For example, based on distance information obtained from cameras 12101 to 12104, microcomputer 12051 can extract three-dimensional objects as the preceding vehicle by calculating the distances to each three-dimensional object within the camera range 12111 to 12114 and how these distances change over time (relative speed to vehicle 12100). Specifically, it can identify the three-dimensional object closest to the preceding vehicle on its path and that is traveling in approximately the same direction as vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, microcomputer 12051 can set a pre-defined distance that should be ensured for the preceding vehicle and execute automatic braking control (including follow-stop control) and automatic acceleration control (including follow-start control). In this way, coordinated control can be performed to achieve autonomous driving, enabling the vehicle to operate autonomously without driver intervention.

[0152] For example, based on distance information obtained from cameras 12101 to 12104, microcomputer 12051 can classify three-dimensional object data into three-dimensional object data for two-wheeled vehicles, ordinary cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, extract the three-dimensional object data, and use the extracted three-dimensional object data to automatically avoid obstacles. For example, microcomputer 12051 distinguishes obstacles around vehicle 12100 into obstacles that the driver of vehicle 12100 can visually identify and obstacles that are difficult to visually identify. Then, microcomputer 12051 determines the collision risk, which represents the degree of danger of colliding with each obstacle, and when the collision risk is above a set value and a collision is likely to occur, microcomputer 12051 provides collision-avoidance assisted driving by issuing a warning to the driver via audio speaker 12061 or display unit 12062, or by performing forced deceleration or evasive steering via drive system control unit 12010.

[0153] At least one of the camera units 12101 to 12104 can be an infrared camera that detects infrared light. For example, the microcomputer 12051 can identify a pedestrian by determining whether a pedestrian exists in the images captured by the camera units 12101 to 12104. This pedestrian identification is performed through the following process: extracting feature points from the images captured by the camera units 12101 to 12104, which are infrared cameras; and performing pattern matching processing on a series of feature points representing the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian exists in the images captured by the camera units 12101 to 12104 and identifies the pedestrian, the sound / image output unit 12052 controls the display unit 12062 to overlay a square outline for emphasis on the identified pedestrian. The sound / image output unit 12052 can also control the display unit 12062 to display an icon or the like representing a pedestrian at a desired location.

[0154] The above have described examples of a mobile body control system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to the camera unit 12031 in the configuration described above. Specifically, the light detection device (e.g., light detection device 1) according to the first and second embodiments and modifications 1 and 2 can be applied to the camera unit 12031. By applying the technology according to the present disclosure to the camera unit 12031, a high-definition captured image with very little noise can be obtained, and therefore high-precision control utilizing the captured image can be performed in the mobile body control system.

[0155] The first and second embodiments, variations 1 and 2, as well as applicable and application examples have been described above. However, the content of this disclosure is not limited to the above embodiments, and various variations are possible. For example, in the above embodiments, the technology was described using a SPAD sensor as an example, but it is not limited thereto. This technology can achieve similar effects by being applied to any semiconductor device in which a through-wire penetrating one semiconductor layer is electrically connected to an impurity region disposed on the surface of another semiconductor layer in a stack of multiple semiconductor layers.

[0156] Furthermore, the optical detection device disclosed herein does not necessarily include all the constituent elements described in the above embodiments, and on the contrary, may include other layers.

[0157] Furthermore, the polarity of the semiconductor regions used to constitute the photodetector of this disclosure can be reversed. Additionally, the photodetector of this disclosure can use holes as signal charges.

[0158] Furthermore, in the photodetector disclosed herein, the potentials of each are not limited as long as a reverse bias voltage is applied between the anode and the cathode to induce avalanche multiplication.

[0159] Furthermore, in the first embodiment described above, an example of using a Si substrate as the semiconductor layer 11 is shown. However, for example, the semiconductor layer 11 can also use a germanium (Ge) substrate, or a compound semiconductor substrate of silicon (Si) and germanium (Ge) (e.g., silicon-germanium (SiGe)). When a Si substrate is used as the semiconductor layer 11, information about visible light can be primarily acquired in the SPAD pixel. When the aforementioned compound semiconductor substrate is used as the semiconductor layer 11, information about short-wave infrared band wavelengths can be primarily acquired.

[0160] Furthermore, the shape of the unit pixel P is not limited to a rectangular shape. For example, the unit pixel P can be octagonal, and the multiple unit pixels P used to constitute the pixel array section 100A can also be arranged in a honeycomb pattern.

[0161] Note that the effects described in the above implementation schemes are examples, and other effects may exist or may include other effects.

[0162] Note that this disclosure can have the following configuration. According to this technology with the following configuration, a photoelectric conversion layer is disposed between a first semiconductor layer and an on-chip lens disposed for each pixel, wherein the first semiconductor layer has a single-photon avalanche diode as a light-receiving element disposed for each pixel. The area of ​​this photoelectric conversion layer in a planar view is smaller than the area of ​​the light-receiving portion of the light-receiving element. Therefore, while suppressing the decrease in sensitivity of the light-receiving element, the separation ratio of the photoelectric conversion layer is ensured. Thus, imaging characteristics can be improved. (1) A light detection device, comprising: A first semiconductor layer having a first surface and a second surface opposite to each other, and having a single-photon avalanche diode as a light receiving element for each pixel; On-chip lenses, arranged for each pixel on the second surface side of the first semiconductor layer; and A photoelectric conversion layer is disposed between the second surface of the first semiconductor layer and the on-chip lens, and the area of ​​the photoelectric conversion layer in the plan view is smaller than the area of ​​the light receiving part of the light receiving element. (2) The optical detection device according to (1) further includes: A second semiconductor layer is disposed on the first surface side of the first semiconductor layer. In this process, a plurality of transistors for constituting a readout circuit are disposed in the second semiconductor layer, and the readout circuit outputs a pixel signal based on the charge output from each pixel. (3) The optical detection device according to (2) further includes: Through-wires penetrating the first semiconductor layer The photoelectric conversion layer and the readout circuit are electrically connected via the through wiring. (4) The optical detection device according to (2) or (3), wherein, The readout circuit includes: a first readout circuit for acquiring a first pixel signal from the light receiving element; and a second readout circuit for acquiring a second pixel signal from the photoelectric conversion layer. (5) The optical detection device according to (4), wherein, At least a portion of the first readout circuit is disposed in the second semiconductor layer. (6) The optical detection device according to (4) or (5), wherein, At least a portion of the second readout circuit is disposed in the second semiconductor layer. (7) The light detection apparatus according to any one of (3) to (6), wherein, The through wiring is positioned between adjacent pixels. (8) The light detection apparatus according to any one of (1) to (7), wherein, The photoelectric conversion layer is an organic photoelectric conversion layer containing organic materials. (9) The light detection apparatus according to any one of (1) to (8), wherein, The first semiconductor layer has a pixel array portion, in which a plurality of pixels are arranged in an array along an in-plane direction, and The organic photoelectric conversion layer is disposed in a portion or all of the pixels among the plurality of pixels. (10) The light detection apparatus according to any one of (1) to (9), wherein, The first semiconductor layer has a pixel array portion, in which a plurality of pixels, including red pixels, green pixels, and blue pixels, are arranged in an array along an in-plane direction. The organic photoelectric conversion layer is disposed only in the green pixel among the plurality of pixels. (11) The light detection apparatus according to any one of (1) to (10), wherein, The first semiconductor layer has a pixel array portion in which a plurality of pixels are arranged in an array along an in-plane direction. Each of the plurality of pixels includes a plurality of sub-pixels capable of acquiring phase difference information, and The organic photoelectric conversion layer is disposed in a portion or all of the sub-pixels among the plurality of sub-pixels. (12) The optical detection device according to (11), wherein, A voltage is applied individually to each of the photoelectric conversion layers disposed in the plurality of sub-pixels. (13) The light detection apparatus according to any one of (1) to (12) further comprises: A third semiconductor layer has a third surface and a fourth surface that are opposite to each other, and the third semiconductor layer is arranged between the first semiconductor layer and the on-chip lens with the second surface and the third surface of the first semiconductor layer facing each other. The photoelectric conversion layer is a photodiode embedded in and formed within the third semiconductor layer. (14) The optical detection device according to (13) further includes: A first wiring layer is disposed on the second surface side of the first semiconductor layer, and has one or more first pad portions on the surface of the first wiring layer; and A second wiring layer is disposed on the third surface side of the third semiconductor layer, and has one or more second pad portions on the surface of the second wiring layer. The first semiconductor layer and the third semiconductor layer are electrically connected via one or more first pad portions and one or more second pad portions. (15) The light detection apparatus according to any one of (1) to (14) further comprises: A wavelength-selective layer is located between the first semiconductor layer and the photoelectric conversion layer, and selectively transmits light of a predetermined wavelength band. (16) The light detection apparatus according to any one of (1) to (15), wherein, The photoelectric conversion layer performs photoelectric conversion on light with a wavelength band different from that of the light receiving unit. (17) The optical detection device according to (16), wherein, The light receiving unit performs photoelectric conversion on light in the visible light region, and the photoelectric conversion layer performs photoelectric conversion on light in the near-infrared region. (18) The optical detection device according to (17) further includes: A near-infrared cutoff filter is located between the first semiconductor layer and the photoelectric conversion layer, and selectively removes light in the near-infrared region.

[0163] This application claims priority to Japanese Patent Application No. 2023-181236, filed with the Japan Patent Office on October 20, 2023, the entire contents of which are incorporated herein by reference.

[0164] Those skilled in the art should be able to conceive of various modifications, combinations, sub-combinations and variations based on design requirements and other factors, and it should be understood that such modifications, combinations, sub-combinations and variations all fall within the scope of the appended claims and their equivalents.

Claims

1. A light detection device, comprising: A first semiconductor layer having a first surface and a second surface opposite to each other, and having a single-photon avalanche diode as a light receiving element for each pixel; On-chip lenses are arranged on the second surface side of the first semiconductor layer for each pixel; as well as A photoelectric conversion layer is disposed between the second surface of the first semiconductor layer and the on-chip lens, and the area of ​​the photoelectric conversion layer in the plan view is smaller than the area of ​​the light receiving part of the light receiving element.

2. The optical detection device according to claim 1, further comprising: A second semiconductor layer is disposed on the first surface side of the first semiconductor layer. In this process, a plurality of transistors for constituting a readout circuit are disposed in the second semiconductor layer, and the readout circuit outputs a pixel signal based on the charge output from each pixel.

3. The optical detection device according to claim 2, further comprising: Through-wires penetrating the first semiconductor layer The photoelectric conversion layer and the readout circuit are electrically connected via the through wiring.

4. The optical detection device according to claim 2, wherein, The readout circuit includes: a first readout circuit for acquiring a first pixel signal from the light receiving element; and a second readout circuit for acquiring a second pixel signal from the photoelectric conversion layer.

5. The optical detection device according to claim 4, wherein, At least a portion of the first readout circuit is disposed in the second semiconductor layer.

6. The optical detection device according to claim 4, wherein, At least a portion of the second readout circuit is disposed in the second semiconductor layer.

7. The optical detection device according to claim 3, wherein, The through wiring is positioned between adjacent pixels.

8. The optical detection device according to claim 1, wherein, The photoelectric conversion layer is an organic photoelectric conversion layer containing organic materials.

9. The optical detection device according to claim 1, wherein, The first semiconductor layer has a pixel array portion, in which a plurality of pixels are arranged in an array along an in-plane direction, and The organic photoelectric conversion layer is disposed in a portion or all of the pixels among the plurality of pixels.

10. The optical detection device according to claim 1, wherein, The first semiconductor layer has a pixel array portion, in which a plurality of pixels, including red pixels, green pixels, and blue pixels, are arranged in an array along an in-plane direction. The organic photoelectric conversion layer is disposed only in the green pixel among the plurality of pixels.

11. The optical detection device according to claim 1, wherein, The first semiconductor layer has a pixel array portion in which a plurality of pixels are arranged in an array along an in-plane direction. Each of the plurality of pixels includes a plurality of sub-pixels capable of acquiring phase difference information, and The organic photoelectric conversion layer is disposed in a portion or all of the sub-pixels among the plurality of sub-pixels.

12. The optical detection device according to claim 11, wherein, A voltage is applied individually to each of the photoelectric conversion layers disposed in the plurality of sub-pixels.

13. The optical detection device according to claim 1, further comprising: A third semiconductor layer has a third surface and a fourth surface that are opposite each other, and the third semiconductor layer is arranged between the first semiconductor layer and the on-chip lens such that the second surface and the third surface of the first semiconductor layer face each other. The photoelectric conversion layer is a photodiode embedded in and formed within the third semiconductor layer.

14. The optical detection device according to claim 13, further comprising: A first wiring layer is disposed on the second surface side of the first semiconductor layer, and has one or more first pad portions on the surface of the first wiring layer; and A second wiring layer is disposed on the third surface side of the third semiconductor layer, and has one or more second pad portions on the surface of the second wiring layer. The first semiconductor layer and the third semiconductor layer are electrically connected via one or more first pad portions and one or more second pad portions.

15. The optical detection device according to claim 1, further comprising: A wavelength-selective layer is located between the first semiconductor layer and the photoelectric conversion layer, and selectively transmits light of a predetermined wavelength band.

16. The optical detection device according to claim 1, wherein, The photoelectric conversion layer performs photoelectric conversion on light with a wavelength band different from that of the light receiving unit.

17. The optical detection device according to claim 16, wherein, The light receiving unit performs photoelectric conversion on light in the visible light region, and the photoelectric conversion layer performs photoelectric conversion on light in the near-infrared region.

18. The optical detection device according to claim 17, further comprising: A near-infrared cutoff filter is located between the first semiconductor layer and the photoelectric conversion layer, and selectively removes light in the near-infrared region.

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