Light detector and distance measuring device

Abstract

A photodetector according to an embodiment of the present invention includes: a first semiconductor substrate having a first surface and a second surface facing each other and including a pixel array portion in which a plurality of pixels are arranged in an array in an in-plane direction; a light-receiving section provided within the first semiconductor substrate for each pixel and generating a carrier corresponding to the amount of received light by photoelectric conversion; a multiplication section that is provided on the first surface for each pixel and that multiplies carrier avalanche generated in the light-receiving section; an insulating layer stacked on the first surface and having one or more openings provided at a predetermined position; one or more polysilicon films provided on the first surface side via the insulating layer at least along a boundary of pixels adjacent to each other and electrically connected to at least the light receiving portion through the one or more openings; one or more first wirings provided along the pixel outer shape on the first surface side; and one or a plurality of first connection wirings provided along the pixel outer shape on the first surface side and electrically connecting the one or a plurality of polysilicon films and the one or a plurality of first wirings.

Description

Technical Field

[0001] The present invention relates to a photodetector using, for example, an avalanche photodiode and a distance measuring device. Background Art

[0002] In the SPAD array sensor, photons generated when the multiplication section multiplies electrons can enter adjacent pixels directly or by reflection, and may be erroneously detected in the adjacent pixels. In order to prevent erroneous detection, for example, Patent Document 1 discloses a photodetector in which a contact electrode wiring is provided as a light shielding wall, and the contact electrode wiring divides an interlayer insulating film into respective portions corresponding to two adjacent photoelectric converters. Citation list Patent Literature

[0003] Patent Document 1: International Publication No. WO2022 / 131109 Summary of the invention

[0004] Incidentally, in the photodetector, in order to achieve miniaturization, it is necessary to improve the withstand voltage performance.

[0005] It is desirable to provide a photodetector and a distance measuring device capable of improving withstand voltage performance against edge breakdown while suppressing crosstalk.

[0006] The photodetector of the embodiment of the present disclosure includes: a first semiconductor substrate having a first surface and a second surface opposite to each other, and including a pixel array section in which a plurality of pixels are arranged in an array in an in-plane direction; a light receiving section, which is provided inside the first semiconductor substrate for each of the pixels and generates carriers corresponding to the amount of received light by photoelectric conversion; a multiplication section, which is provided on the first surface for each of the pixels and avalanche multiplies the carriers generated in the light receiving section; an insulating layer, which is stacked on the first surface, the insulating layer having one or more openings provided at predetermined positions; one or more polysilicon films, which are provided on the first surface side at least along the boundaries of the pixels adjacent to each other, the insulating layer being interposed between the first surface and the one or more polysilicon films, and the one or more polysilicon films being electrically connected to at least the light receiving section through the one or more openings; one or more first wirings, which are provided on the first surface side along the outer shape of the pixels; and one or more first connecting wirings, which are provided on the first surface side along the outer shape of the pixels and electrically connect the one or more polysilicon films and the one or more first wirings to each other.

[0007] A distance measuring device according to an embodiment of the present disclosure includes: an optical system; a photodetector; and a signal processing circuit that calculates a distance to a measurement target based on an output signal of the photodetector, and includes the photodetector according to an embodiment of the present disclosure as the photodetector.

[0008] In the photodetector and distance measuring device according to each embodiment of the present disclosure: the insulating layer having the one or more openings respectively arranged at predetermined positions and the one or more polysilicon films electrically connected to the light receiving unit through the one or more openings of the insulating layer are arranged on the first surface side of the semiconductor substrate; and the one or more first connecting wirings electrically connected to the light receiving unit provided on the first surface side of the semiconductor substrate are connected to the one or more polysilicon films. The one or more polysilicon films, the one or more first wirings and the one or more first connecting wirings have a layout formed at least along the boundaries of adjacent pixels, respectively. This prevents the entry of leakage light from adjacent pixels and can ensure the distance between the anode that applies voltage to the light receiving unit and the cathode that applies voltage to the multiplication unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 : is a schematic cross-sectional view showing an example of the configuration of a photodetector according to the first embodiment of the present disclosure. Figure 2 It is shown Figure 1 A schematic plan view of an example of the configuration of a light detector is shown. Figure 3 It is shown Figure 1 A block diagram of an example of a schematic construction of a photodetector is shown. Figure 4 yes Figure 1 An example of an equivalent circuit diagram of a unit pixel of a photodetector is shown. Figure 5 It is shown Figure 1 FIG. 2 is a schematic plan view of another example of the configuration of the photodetector. Figure 6 : is a schematic cross-sectional view showing an example of a configuration of a photodetector according to a modification example of the present disclosure. Figure 7 is a schematic cross-sectional view showing an example of a configuration of a photodetector according to a second embodiment of the present disclosure. Figure 8 yes Figure 7 An example of an equivalent circuit diagram of a unit pixel of a photodetector is shown. Fig. 9 is a schematic cross-sectional view showing an example of a configuration of a photodetector according to a third embodiment of the present disclosure. Fig.10 It is shown Fig. 9 A schematic plan view of an example of the configuration of a light detector is shown. Fig.11 It is shown that the use Figure 1 or other functional block diagrams of examples of electronic devices for light detectors shown in the accompanying drawings. Fig. 12A It is shown that the use Figure 1 The photodetector shown is a schematic diagram of an example of the overall configuration of a light detection system. Fig. 12B It is shown Fig. 12A A diagram showing an example of a circuit configuration of a light detection system. Fig.13 is a block diagram depicting an example of a schematic configuration of a vehicle control system. Fig.14 It is a diagram for assisting in explaining an example of the installation positions of the vehicle exterior information detection unit and the imaging unit. DETAILED DESCRIPTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description is only a specific example of the present disclosure, and the present disclosure should not be limited to the following aspects. In addition, the present disclosure is not limited to the arrangement, size, size ratio, etc. of the various components shown in the accompanying drawings. It should be noted that the description is given in the following order. 1. First Embodiment (Photodetector in which a connection wiring serving as a light shield and provided at the periphery of a pixel is electrically connected to an anode through a polysilicon film) 2. Modification Example (Other Examples of Photodetector Structure) 3. Second Embodiment (Photodetector in which a readout circuit is provided on a substrate different from a light receiving element and stacked together) 4. Third Embodiment (Photodetector provided with another connecting wiring directly connected to the anode which is different from the connecting wiring which plays a light shielding role and is provided at the periphery of the pixel) 5. Application Examples 6. Practical application examples [1. First embodiment]

[0011] Figure 1 An example of a cross-sectional configuration of a photodetector (photodetector 1 ) according to the first embodiment of the present disclosure is schematically shown. Figure 2 Schematically shows Figure 1 An example of a planar configuration of the photodetector 1 is shown, and Figure 1 Shown with Figure 2The light detector 1 is applied to, for example, a distance image sensor (a distance image device 1000 described later; see Fig.11 ) or image sensor, etc. [1-1. Schematic Configuration of Photodetector]

[0012] Figure 3 It is shown Figure 1 A block diagram of a schematic configuration of the optical detector 1 is shown, and Figure 4 Shows Figure 1 1 is an example of an equivalent circuit of a unit pixel P of the photodetector 1 shown in FIG. The photodetector 1 includes, for example, a pixel array section 100A in which a plurality of unit pixels P are arranged in a row direction and a column direction. Figure 3 As shown, the photodetector 1 includes a bias voltage applying section 110 and a pixel array section 100A. The bias voltage applying section 110 applies a bias voltage to each unit pixel P in the pixel array section 100A. In this embodiment, the case where electrons are read as signal charges is described.

[0013] like Figure 3 As shown, the unit pixel P includes a light receiving element 12, a quenching resistor element 120 including a p-type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), and an inverter 130 including, for example, a complementary MOSFET.

[0014] The light receiving element 12 converts incident light into an electrical signal by photoelectric conversion, and outputs the converted electrical signal. The light receiving element 12 converts incident light (photons) into electrical signals by photoelectric conversion, and outputs a pulse corresponding to the incidence of the photons. The light receiving element 12 is, for example, a SPAD (Single Photon Avalanche Diode) element. The SPAD element has, for example, the following characteristics: an avalanche multiplication region 12X (depletion layer) is formed by applying a large negative voltage to the cathode, and the electrons generated in response to the incidence of a single photon cause avalanche multiplication and cause a large current to flow. The light receiving element 12 has, for example, an anode connected to a bias voltage applying section 110 and a cathode connected to a source terminal of a quenching resistor element 120. A device voltage V is applied from the bias voltage applying section 110 to the anode of the light receiving element 12. BD .

[0015] The quenching resistor element 120 is connected in series to the light receiving element 12, and its source terminal is connected to the cathode of the light receiving element 12, and its drain terminal is connected to a power supply not shown. An excitation voltage V is applied from the power supply to the drain terminal of the quenching resistor element 120. E When the voltage of the electrons subjected to avalanche multiplication of the light receiving element 12 reaches the negative voltage V BD When , the quenching resistance element 120 performs quenching in which the electrons multiplied by the light receiving element 12 are discharged to return the voltage to the initial voltage.

[0016] The inverter 130 has an input terminal connected to the cathode of the light receiving element 12 and the source terminal of the quenching resistor element 120, and an output terminal connected to the arithmetic processing section of the later stage not shown. The inverter 130 outputs a light receiving signal based on the carriers (signal charges) multiplied by the light receiving element 12. More specifically, the inverter 130 shapes the voltage generated by the electrons multiplied by the light receiving element 12. Then, the inverter 130 outputs a light receiving signal (APD OUT) to the arithmetic processing section, in which, for example, a single font arrival time is used as a starting point, and a signal is generated. Figure 4 For example, the arithmetic processing section performs arithmetic processing for determining the distance to the object based on the timing of generating a pulse representing the arrival time of a single font in each light receiving signal, and determines the distance of each unit pixel P. Then, based on the distance, a distance image is generated in which the distances to the object detected by a plurality of unit pixels P are arranged in a planar manner. [1-1. Cross-sectional structure of photodetector]

[0017] The light detector 1 is, for example, a so-called back-illuminated light detector, in which a logic substrate 20 is stacked on the front side of a sensor substrate 10 (for example, the front side (first side 11S1) of a semiconductor substrate 11 constituting the sensor substrate 10), and receives light from the back side of the sensor substrate 10 (for example, the back side (second side 11S2) of the semiconductor substrate 11 constituting the sensor substrate 10).

[0018] As described above, the sensor substrate 10 and the logic substrate 20 are stacked in the photodetector 1. The sensor substrate 10 includes a semiconductor substrate 11 composed of, for example, a silicon substrate, and a multilayer wiring layer 19 provided on the first face 11S1 side of the semiconductor substrate 11. For each unit pixel P, the light receiving portion 13 and the multiplication portion 14 constituting the light receiving element 12 are formed, for example, to be buried in the semiconductor substrate 11. The semiconductor substrate 11 also includes a pixel isolation portion 17 that electrically isolates adjacent unit pixels P from each other. The pixel isolation portion 17 is provided between a plurality of unit pixels P adjacent in the row direction and the column direction to extend from the first face 11S1 of the semiconductor substrate 11 to the second face 11S2. The pixel isolation portion 17 is provided in a grid pattern in a plan view of the entire pixel array portion 100A. The semiconductor substrate 11 also includes a contact layer 15 (anode) electrically connected to the light receiving portion 13 and a contact layer 16 (cathode) electrically connected to the multiplication portion 14.

[0019] The photodetector 1 of the present embodiment has a structure in which the contact layer 15 and the wiring (wiring 193-1) are electrically connected to each other through the polysilicon film 192 and the through hole V1a. The wiring 193-1 is one wiring contained in the wiring layer 193 within the multilayer wiring layer 19 provided on the first face 11S1 of the semiconductor substrate 11. The polysilicon film 192, the wiring 193-1, and the through hole V1a are respectively formed continuously along the boundaries of the unit pixels P adjacent to each other, thereby surrounding the light receiving element 12 in a plan view. The gate insulating layer 191 is provided between the first face 11S1 of the semiconductor substrate 11 and the polysilicon film 192. The polysilicon film 192 is electrically connected to the contact layer 15 through the opening 191H formed in the gate insulating layer 191.

[0020] It should be noted that the symbols "p" and "n" in the figure represent a p-type semiconductor region and an n-type semiconductor region, respectively. In addition, the "+" and "-" at the end of "p" represent the impurity concentration of the p-type semiconductor region, respectively. Similarly, the "+" and "-" at the end of "n" represent the impurity concentration of the n-type semiconductor region, respectively. Here, having more "+" means a higher impurity concentration, and having more "-" means a lower impurity concentration. The same applies to the following figures.

[0021] The semiconductor substrate 11 has a first surface 11S1 and a second surface 11S2 facing each other. The semiconductor substrate 11 includes, for example, a p-well (p) shared by a plurality of unit pixels P. For each unit pixel P, the semiconductor substrate 11 is provided with an n-type semiconductor region (n) 111 constituting a light receiving portion 13, in which the impurity concentration is controlled to be, for example, n-type. The semiconductor substrate 11 is also provided with a p-type semiconductor region (p) constituting a multiplication portion 14 on the first surface 11S1 side. + )14X and n-type semiconductor region (n +)14Y. This allows the light receiving element 12 to be formed for each unit pixel P. A pixel isolation portion 17 that electrically isolates adjacent unit pixels P from each other is provided at the periphery of the unit pixel P. A p-type semiconductor region (p) 112 having an impurity concentration higher than that of the p-well is provided between the light receiving element 12 and the pixel isolation portion 17.

[0022] The light receiving element 12 has a multiplication region (avalanche multiplication region 12X) for avalanche multiplication of carriers through a high electric field region. As described above, the light receiving element 12 is a SPAD element that can form an avalanche multiplication region 12X by applying a large negative voltage to the cathode (contact layer 16) and can avalanche multiply electrons generated by the incidence of a single photon.

[0023] The light receiving section 13 corresponds to a specific example of the "light receiving section" of the present disclosure. The light receiving section 13 has a photoelectric conversion function of absorbing light incident from the second surface 11S2 side of the semiconductor substrate 11 and generating carriers corresponding to the amount of received light. As described above, the light receiving section 13 includes an n-type semiconductor region (n) 111 whose impurity concentration is controlled to be n-type, and the carriers (electrons) generated by the light receiving section 13 are transmitted to the multiplication section 14 through the potential gradient.

[0024] The multiplication section 14 corresponds to a specific example of the "multiplication section" of the present disclosure. The multiplication section 14 avalanche multiplies the carriers (electrons in this case) generated by the light receiving section 13. The multiplication section 14 is composed of, for example, a p-type semiconductor region (p-type semiconductor region) having an impurity concentration higher than that of a p-well (p-type semiconductor region). + )14X and an n-type semiconductor region (n)111 having an impurity concentration higher than that of the n-type semiconductor region (n)111 + )14Y. p-type semiconductor region (p + )14X and n-type semiconductor region (n + ) 14Y is provided on the first surface 11S1 side. The n-type semiconductor region (n + )14Y and p-type semiconductor region (p + ) 14X is formed to be stacked in sequence from the first surface 11S1 side.

[0025] The p-type semiconductor region (p + )14X area and n-type semiconductor region (n + )14Y has substantially the same area in the XY plane direction. However, the present invention is not limited thereto. For example, the n-type semiconductor region (n + )14Y in the XY plane direction can be smaller than the p-type semiconductor region (p + )14X is the area in the XY plane, or the p-type semiconductor region (p + )14X can have an area in the XY plane direction larger than the n-type semiconductor region (n+ )14Y has an area in the XY plane direction and can be set on the entire surface of the unit pixel P divided by the pixel isolation part 17.

[0026] In the light receiving element 12, an avalanche multiplication region 12X is formed in a p-type semiconductor region (p + )14X and n-type semiconductor region (n + The avalanche multiplication region 12X is formed by applying a large negative voltage to the cathode in the p-type semiconductor region (p + )14X and n-type semiconductor region (n + ) 14Y. In the avalanche multiplication region 12X, electrons (e - ).

[0027] The first surface 11S1 of the semiconductor substrate 11 is further provided with a contact layer 15 and a contact layer 16. The contact layer 15 includes a p-type semiconductor region (p) electrically connected to the n-type semiconductor region (n) 111 constituting the light receiving section 13. ++ The contact layer 16 includes an n-type semiconductor region (n + )14Y electrically connected n-type semiconductor region (n ++ ).

[0028] like Figure 2 As shown, for example, a contact layer 15 is provided at four corners of a unit pixel P having a substantially rectangular shape in the XY plane direction, and the contact layer 15 is connected to the bias application section 110 as an anode of the light receiving element 12. Figure 2 As shown, for example, one contact layer 16 is provided at the approximate center of the unit pixel P, and the contact layer 16 is connected to the source terminal of the quenching resistance element 120 as the cathode of the light receiving element 12 .

[0029] The pixel isolation section 17 electrically isolates adjacent unit pixels P from each other, and is arranged in a grid pattern, for example, in a plan view, to separate a plurality of unit pixels P in the pixel array section 100A from each other. The pixel isolation section 17 extends from the first surface 11S1 to the second surface 11S2 of the semiconductor substrate 11, and, for example, penetrates the semiconductor substrate 11. The pixel isolation section 17 is composed of, for example, an insulating film 17A and a light shielding film 17B buried in the insulating film 17A. The pixel isolation section 17 may be provided from the second surface 11S2 side of the semiconductor substrate 11. However, the present disclosure is not limited thereto, and the pixel isolation section 17 may be formed from the first surface 11S1 side of the semiconductor substrate 11.

[0030] The insulating film 17A is made of, for example, silicon oxide (SiOx ) and the like. The light shielding film 17B is formed using, for example, a metal material having a light shielding property or a silicon compound thereof, the metal material being, for example, tungsten (W), aluminum (Al), copper (Cu), cobalt (Co), nickel (Ni) or titanium (Ti). In addition, the light shielding film 17B can also be formed using polycrystalline silicon (Poly-Si). The light shielding film 17B can be provided with a widening portion 17X formed to extend on the second surface 11S2 of the semiconductor substrate 11 to suppress the incidence of oblique incident light between adjacent unit pixels P.

[0031] The side and bottom surfaces of the pixel separation section 17 and the second surface 11S2 of the semiconductor substrate 11 may be provided with, for example, a layer having fixed charges (fixed charge film 18). The fixed charge film 18 may be a film having positive fixed charges or a film having negative fixed charges.

[0032] As a constituent material of the fixed charge film 18, it is preferable to use a semiconductor material or a conductive material having a band gap wider than that of the semiconductor substrate 11. This makes it possible to suppress the generation of dark current at the interface of the semiconductor substrate 11. Examples of constituent materials of the fixed charge film 18 include hafnium oxide (HfO x ), aluminum oxide (AlO x )、ZrO x ), tantalum oxide (TaO x ), titanium oxide (TiO x ), lanthanum 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 ), Lutetium oxide (LuO x ), yttrium oxide (YO x ), Hafnium Nitride (HfN x ), aluminum nitride (AlN x ), Hafnium Oxynitride (HfO x N y ) and aluminum oxynitride (AlO x N y ).

[0033] The semiconductor substrate 11 also includes a readout circuit that outputs a pixel signal based on the charge output from the unit pixel P.

[0034] In the multilayer power distribution layer 19 , a gate insulating layer 191 and an interlayer insulating layer 194 are stacked in order from the first surface 11S1 side of the semiconductor substrate 11 .

[0035] The gate insulating layer 191 corresponds to a specific example of the “insulating layer” of the present disclosure. The gate insulating layer 191 includes, for example, a stacked film of an insulating film 191A and an insulating film 191B, and is formed on the first surface 11S1 of the semiconductor substrate 11. The gate insulating layer 191 has one or more openings 191H at predetermined positions, and the first surface 11S1 is exposed at the openings. Specifically, as shown in FIG. Figure 2 As shown, one or more openings 191H are provided on each contact layer 15 provided at each of the four corners of the unit pixel P and on the contact layer 16 provided at the approximate center of the unit pixel P. The gate insulating layer 191 may be made of, for example, silicon oxide (SiO x )、TEOS、Silicon Nitride (SiN x ), silicon oxynitride (SiO x N y ) etc. For example, the insulating film 191A includes a silicon oxide film, and the insulating film 191B includes a silicon nitride film.

[0036] For example, as a transmission path for supplying a voltage to be applied to the semiconductor substrate 11 or the light receiving element 12 or for extracting carriers generated by the light receiving element 12, the interlayer insulating layer 194 is provided with a plurality of polysilicon films 192, one or more wiring layers (for example, the wiring layer 193), a plurality of pad electrodes 195 and a plurality of through holes (for example, through hole V1a, through hole V1b and through hole V2).

[0037] The multiple polysilicon films 192 correspond to a specific example of "one or more polysilicon films" of the present disclosure. Each of the multiple polysilicon films 192 is disposed on the gate insulating layer 191 and is electrically connected to the corresponding contact layers 15 and 16 through an opening 191H disposed on the corresponding contact layers 15 and 16. The multiple polysilicon films 192 may be formed using polysilicon (Poly-Si); however, the present disclosure is not limited thereto. The multiple polysilicon films 192 may include any material that is configured to have a selectivity ratio with the insulating film included in the gate insulating layer 191 when performing an etching process, examples of which include refractory metals such as tungsten (W) or nickel (Ni), barrier metals such as titanium nitride (TiN) or tantalum nitride (TaN), and silicides such as nickel silicide (NiSi) or cobalt silicide (CoSi).

[0038] The wiring layer 193 includes a wiring 193-1 corresponding to the "first wiring" of the present disclosure and a wiring 193-2 corresponding to the "second wiring" of the present disclosure, and is provided in the interlayer insulating layer 194. The wiring layer 193 is formed using, for example, aluminum (Al), copper (Cu), tungsten (W), or the like. It should be noted that Figure 1 An example in which one wiring layer 193 is formed in the multilayer wiring layer 19 is shown; however, the total number of wiring layers in the multilayer wiring layer 19 is not limited, and two or more wiring layers may be formed.

[0039] The plurality of pad electrodes 195 are used for connection with the logic substrate 20 and are embedded in the front surface (front surface 19S1 of the multilayer wiring layer 19) on the side opposite to the semiconductor substrate 11 side of the interlayer insulating layer 194. The plurality of pad electrodes 195 are formed using, for example, copper (Cu).

[0040] The through hole V1a corresponds to a specific example of "one or more first connection wirings" of the present disclosure, and electrically connects a part of the wiring of the wiring layer 193 (wiring 193-1) to the polysilicon film 192 electrically connected to the contact layer 15. The through hole V1b corresponds to a specific example of "second connection wiring" of the present disclosure, and electrically connects a part of the wiring of the wiring layer 193 (wiring 193-2) to the polysilicon film 192 electrically connected to the contact layer 16. The through hole V2 electrically connects the plurality of wirings constituting the wiring layer 193 to the plurality of pad electrodes 195. The through holes V1a, V1b, and V2 are formed using, for example, a metal material having a light-shielding property, such as tungsten (W), aluminum (Al), copper (Cu), cobalt (Co), nickel (Ni), or titanium (Ti), or a silicon compound thereof.

[0041] like Figure 1 and Figure 2 As shown, the polysilicon film 192, a part of the wiring (wiring 193-1) in the wiring layer 193, and the through hole V1a are respectively formed continuously along the boundaries of adjacent pixels, thereby surrounding the periphery of the light receiving element 12 in a plan view. This makes it possible to prevent photons generated when carriers (electrons in this case) are multiplied by the multiplying section 14 from entering the adjacent unit pixel P by reflection between the first surface 11S1 of the semiconductor substrate 11 and the wiring layer 193. In addition, the device voltage V is increased by the opening 191H provided at each of the four corners. BD is applied to the light receiving portion 13, so that the distance between the anode and the cathode can be ensured.

[0042] It should be noted that Figure 2 In the embodiment, the contact layer 15 and the polysilicon film 192 formed at each of the four corners of the unit pixel P are connected to each other through one opening 191H; however, the present disclosure is not limited thereto. Figure 5As shown, the contact layer 15 and the polysilicon film 192 can be connected to each other through a plurality of openings 191H. In addition, for example, the through hole V1a is not necessarily formed continuously along the outer shape of the unit pixel P (for example, the boundary between adjacent unit pixels P), for example, a plurality of through holes V1a each having a columnar shape can be provided along the outer shape of the unit pixel P.

[0043] The logic substrate 20 includes a semiconductor substrate 21 composed of, for example, a silicon substrate, and a multilayer wiring layer 22. The semiconductor substrate 21 has a first surface 21S1 and a second surface 21S2 that are opposite to each other, and a logic circuit is formed on the first surface 21S1, the logic circuit including, for example: the above-mentioned bias voltage applying section 110, which has a cathode voltage generating circuit 51, an anode voltage generating circuit 52, and modulation voltage generating circuits 53A and 53B; a vertical drive circuit; a column signal processing circuit; a horizontal drive circuit; and an output circuit, etc.

[0044] In the multilayer wiring layer 22, for example, a gate wiring 221 of a transistor constituting a logic circuit and wiring layers 222, 223, 224, and 225 each including one or more wirings are stacked in order from one side of the semiconductor substrate 21, with an interlayer insulating layer 226 interposed therebetween. A plurality of pad electrodes 227 are embedded in the front surface (front surface 22S1 of the multilayer wiring layer 22) on the side opposite to the semiconductor substrate 21 side of the interlayer insulating layer 226. The plurality of pad electrodes 227 are electrically connected to a portion of the wiring of the wiring layer 225 through the through hole V3.

[0045] In the same manner as the interlayer insulating layer 194, the interlayer insulating layer 117 is made of, for example, silicon oxide (SiO x )、TEOS、Silicon Nitride (SiN x ), silicon oxynitride (SiO x N y ) or a stacked film of two or more thereof.

[0046] In the same manner as the wiring layer 193 , the gate wiring 221 and the wiring layers 222 , 223 , 224 , and 225 are formed using, for example, aluminum (Al), copper (Cu), tungsten (W), or the like.

[0047] A pad electrode 227 is exposed on the bonding surface with the sensor substrate 10 (the front surface 22S1 of the multilayer wiring layer 22) and is used, for example, for connection with the sensor substrate 10. The pad electrode 227 is formed of, for example, copper (Cu) in the same manner as the pad electrode 195.

[0048] In the photodetector 1, for example, Cu-Cu bonding is performed between the pad electrode 195 and the pad electrode 227. This allows the cathode of the light receiving element 12 to be electrically connected to the quenching resistance element 120 provided on the logic substrate 20 side, and the anode of the light receiving element 12 to be electrically connected to the bias voltage applying section 110.

[0049] On the light receiving face (second face 11S2 ) side of the semiconductor substrate 11 , for example, a microlens 33 is provided for each unit pixel P with a protective layer 31 and a color filter 32 interposed between the second face 11S2 and the microlens 33 .

[0050] The microlens 33 collects light incident on the light receiving element 12 from above and is formed using, for example, silicon oxide (SiO x ) and so on. [Function and Effect]

[0051] In the photodetector 1 of the present embodiment, a gate insulating layer 191 having an opening 191H at each of the four corners of the unit pixel P and a polysilicon film 192 in which the opening 191H is buried are provided on the first face 11S1 side of the semiconductor substrate 11, and a through hole V1a electrically connecting a wiring 193-1 provided on the first face 11S1 side of the semiconductor substrate 11 to the light receiving section 13 is connected to the polysilicon film 192. The polysilicon film 192, the through hole V1a, and the wiring 193-1 are respectively formed continuously along the boundaries of adjacent unit pixels P to surround the light receiving element 12. This prevents the entry of leakage light from adjacent unit pixels P, and ensures the distance between the anode (contact layer 15) that applies a voltage to the light receiving section 13 and the cathode (contact layer 16) that applies a voltage to the multiplication section 14. This will be described below.

[0052] In SPAD technology, a high bias voltage is applied to multiply carriers generated by photoelectric conversion of incident light, thereby enabling them to be extracted as a large signal.

[0053] In such a photodetector in which SPAD elements are arranged in an array, photons generated when one SPAD element multiplies carriers (e.g., electrons) may enter another SPAD element adjacent thereto (referred to as an adjacent element) directly or by reflection, and may be erroneously detected by photoelectric conversion and multiplication in the adjacent element. This is referred to as crosstalk.

[0054] As a method for preventing erroneous detection, the above-mentioned photodetector is proposed, wherein a contact electrode wiring having a linear shape connected to an anode or a cathode is provided as a light shielding wall that divides an interlayer insulating film into respective portions corresponding to two adjacent photoelectric converters.

[0055] However, in a photodetector where contact electrode wiring is arranged in a linear shape to surround the photoelectric converter, the shortest distance between the anode and the cathode is shortened to about half the pixel pitch. For example, in a photodetector where a voltage higher than or equal to 10V is applied, voltage resistance may be insufficient.

[0056] In contrast, in the present embodiment, the wiring 193-1 and the connecting wiring V1a are provided in the multilayer wiring layer 19 provided on the first face 11S1 side of the semiconductor substrate 11. The wiring 193-1 and the connecting wiring V1a are continuously along the outer shape of the unit pixel P (for example, the boundary of the adjacent unit pixels P) to surround the periphery of the light receiving element 12. The connecting wiring V1a electrically connects the wiring 193-1 and the contact layer 15 used as an anode to each other. In addition, the gate insulating layer 191 and the polysilicon film 192 are provided in the multilayer wiring layer 19. The gate insulating layer 191 is provided on the first face 11S1 of the semiconductor substrate 11, and has an opening 191H on the contact layer 15. Like the wiring 193-1 and the connecting wiring V1a, the polysilicon film 192 is continuously along the boundary of the adjacent unit pixels P to surround the periphery of the light receiving element 12, and buries the opening 191H, thereby contacting the contact layer 15. The connection wiring V1a is electrically connected to the contact layer 15 through the polysilicon film 192. Therefore, the entry of leakage light from adjacent pixels can be prevented through the polysilicon film 192, the through hole V1a and the wiring 193-1. In addition, the distance between the anode (contact layer 15) and the cathode (contact layer 16) in the unit pixel P is the distance from the four corners of the rectangular unit pixel P to the approximate center, that is, about √2 times the pixel pitch.

[0057] As described above, the photodetector 1 of the present embodiment can improve the withstand voltage performance against edge breakdown while suppressing crosstalk, which is advantageous for miniaturization of the unit pixel P constituting the photodetector 1 .

[0058] Next, the second and third embodiments and modified examples of the present disclosure as well as application examples and practical application examples will be described. Hereinafter, components similar to those of the above-described first embodiment are denoted by the same reference numerals, and description thereof is appropriately omitted. [2. Modifications]

[0059] Figure 6 An example of a cross-sectional structure of a light detector (light detector 1A) according to a modified example of the present disclosure is schematically shown. In the same manner as the first embodiment described above, the light detector 1A is applied to, for example, a distance image sensor (distance image device 1000 described later) or an image sensor that performs distance measurement by a ToF method.

[0060] In the first embodiment, an example has been described in which the contact layer 16 as a cathode disposed at the approximate center of the unit pixel P and the through hole V1b are electrically connected to each other through the polysilicon film 192; however, the present disclosure is not limited thereto. Figure 6 As shown, the contact layer 16 and the via V1b may be directly connected to each other.

[0061] This enables connection to be established without increasing the resistance value between the contact layer 16 and the via V1 b . [3. Second embodiment]

[0062] Figure 7 An example of a cross-sectional configuration of a photodetector (photodetector 2 ) according to a modification example of the present disclosure is schematically shown. Figure 8 Shows Figure 7 An example of an equivalent circuit of a unit pixel P of the photodetector 2 is shown. In the same manner as the first embodiment described above, the photodetector 2 is applied to, for example, a distance image sensor (distance image device 1000 described later) or an image sensor that performs distance measurement by the ToF method.

[0063] In the photodetector 2 of the present embodiment, a readout circuit that outputs a pixel signal based on the charge output from the unit pixel P is provided in a semiconductor substrate (semiconductor layer 40) that is different from the semiconductor substrate 11 on which the light receiving element 12 is provided, and the semiconductor layer 40 is arranged between the semiconductor substrate 11 and the semiconductor substrate 21.

[0064] The semiconductor layer 40 corresponds to a specific example of the "second semiconductor substrate" of the present disclosure. The semiconductor layer 40 is a semiconductor layer including, for example, silicon, and has a first face 40S1 and a second face 40S2 that are opposite to each other. The first face 40S1 of the semiconductor layer 40 is opposite to the first face 11S1 of the semiconductor substrate 11, with the multilayer wiring layer 19A interposed therebetween, and the second face 40S2 of the semiconductor layer 40 is opposite to the first face 21S1 of the semiconductor substrate 21, with the multilayer wiring layer 19B and the multilayer wiring layer 22 interposed therebetween. A portion of a plurality of transistors included in the readout circuit is provided on the second face 40S2 of the semiconductor layer 40. For example, in the readout circuit, a quenching circuit including a quenching resistance element 120 is provided on the semiconductor substrate 11 side. For example, a pulse shaping circuit including an inverting circuit including a P-type MOS transistor 140 and an N-type MOS transistor 150 is provided on the semiconductor layer 40. The semiconductor layer 40 is also provided with, for example, an isolation portion 41 that isolates the semiconductor layer 40 for each unit pixel P and an element isolation region 42 that electrically isolates transistors from each other.

[0065] In the photodetector 2, the above-mentioned wiring layer 193 is provided in a layer of a multilayer wiring layer 19B provided on the second face 40S2 side of the semiconductor layer 40. A through hole V1a electrically connecting the wiring 193-1 to the contact layer 15 and a through hole V1b electrically connecting the wiring 193-2 to the contact layer 16 respectively penetrate the semiconductor layer 40. Specifically, the through holes V1a and V1b respectively penetrate the isolation portion 41 isolating the semiconductor layer 40. Therefore, the semiconductor layer 40 is electrically insulated from the through holes V1a and V1b.

[0066] As described above, in the present embodiment, a portion of the readout circuit is disposed in the semiconductor layer 40, and the semiconductor layer 40 is stacked to form a three-dimensional structure. This makes it possible to reduce the occupied space of the readout circuit compared to the first embodiment described above. It is also possible to simplify the wiring structure of the wiring layer to be disposed in the multilayer wiring layer 19, and reduce the wiring capacitance. In addition, power consumption can also be reduced.

[0067] In addition, as in the present embodiment, the present technology can achieve a greater effect in a photodetector having a three-dimensional structure. For example, as in the present embodiment, in the case where the semiconductor layer 40 having a large refractive index difference is arranged on the first surface 11S1 side of the semiconductor substrate 11, the path for photons to leak to the adjacent unit pixel P becomes complicated due to the increase in the area of ​​the reflection surface, and the number of paths increases. However, in the photodetector 2 of the present embodiment, the through hole V1a that electrically connects the wiring 193-1 and the contact layer 15 to each other passes through the semiconductor layer 40, which makes it possible to prevent the photons reflected by the first surface 40S1 of the semiconductor layer 40 from entering the adjacent unit pixel P. This makes it possible to achieve further miniaturization of the photodetector. [4. Third embodiment]

[0068] Fig. 9 An example of a cross-sectional configuration of a photodetector (photodetector 3 ) according to a third embodiment of the present disclosure is schematically shown. Fig.10 Schematically shows Fig. 9 An example of a planar configuration of the photodetector 3 is shown. In the same manner as the above-described first embodiment, the photodetector 3 is applied to, for example, a distance image sensor (a distance image device 1000 described later) or an image sensor that performs distance measurement by a ToF method.

[0069] In the above-mentioned first embodiment, an example has been described in which the contact layer 15 serving as the anode and the through hole V1a are electrically connected to each other through the polysilicon film 192; however, for example, the polysilicon film 192 may be provided only on the pixel isolation portion 17, and the polysilicon film 192 and the wiring 193-1 may be connected to each other through the through hole V1a, while the wiring 193-1 and the contact layer 15 may be connected to each other not through the polysilicon film 192 but through the through hole V1c penetrating the gate insulating layer 191.

[0070] This makes it possible to select whether or not the through hole V1 is in direct contact with the semiconductor substrate 11 according to the presence or absence of the polysilicon film 192 while achieving advantages similar to those of the above-described first embodiment. [5. Application examples] [Application Example 1]

[0071] Fig.11 An example of a schematic configuration of a distance image device 1000 is shown, which is an electronic device including a photodetector (eg, photodetector 1) according to the above-described first to third embodiments and modifications. The distance image device 1000 corresponds to a specific example of a “distance measuring device” of the present disclosure.

[0072] The distance image apparatus 1000 includes, for example, a light source device 1100 , an optical system 1200 , a light detector 1 , an image processing circuit 1300 , a monitor 1400 , and a memory 1500 .

[0073] The distance image apparatus 1000 receives light (modulated light or pulsed light) projected from the light source device 1100 to the illumination target 1600 and reflected by the surface of the illumination target 1600 , thereby acquiring a distance image corresponding to the distance to the illumination target 1600 .

[0074] The optical system 1200 includes one or more lenses, and guides image light (incident light) from the illumination target 1600 to the photodetector 1 to form an image on a light receiving surface (sensor unit) of the photodetector 1 .

[0075] The image processing circuit 1300 performs image processing for constructing a distance image based on the distance signal supplied from the photodetector 1 , and supplies the distance image (image data) obtained by the image processing to the monitor 1400 for display, or supplies to the memory 1500 for storage (recording).

[0076] In the distance image device 1000 constructed as described above, the application of the above-mentioned light detector (e.g., light detector 1) makes it possible to calculate the distance to the irradiation target 1600 based only on the light receiving signal from the highly stable unit pixel P, and generate a high-precision distance image. That is, the distance image device 1000 is able to obtain a more accurate distance image. [Application Example 2]

[0077] Fig. 12A An example of the overall configuration of a light detection system 2000 including a light detector (eg, light detector 1 ) is schematically shown. Fig. 12BAn example of a circuit configuration of a light detection system 2000 is shown. The light detection system 2000 includes a light emitting device 2001 as a light source portion that emits infrared light L2 and a light detector 2002 as a light receiving portion. As the light detector 2002, for example, the above-described light detector 1 can be used. The light detection system 2000 may further include a system controller 2003, a light source driver 2004, a sensor controller 2005, a light source side optical system 2006, and a camera side optical system 2007.

[0078] The light detector 2002 is configured to detect light L1 and light L2. Light L1 is ambient light from the outside that is detected by an object (measurement target 2100 ( Fig. 12A )). Light L2 is light emitted by the light emitting device 2001 and then reflected by the object 2100. Light L1 is, for example, visible light, and light L2 is, for example, infrared light. Light L1 can be detected by a photoelectric converter in the light detector 2002, and light L2 can be detected in a photoelectric conversion area in the light detector 2002. Image information of the object 2100 can be acquired from light L1, and distance information between the object 2100 and the light detection system 2000 can be acquired from light L2. The light detection system 2000 can be installed on an electronic device such as a smartphone or a moving body such as a car. The light emitting device 2001 can be constructed with, for example, a semiconductor laser, a semiconductor surface emitting laser, or a vertical-cavity surface-emitting laser (VCSEL). As a method for detecting light L2 emitted from the light emitting device 2001 by the light detector 2002, for example, an iTOF method can be adopted; however, the present disclosure is not limited thereto. In the iTOF method, the photoelectric converter is constructed to measure the distance to the object 2100 by, for example, optical time of flight (TOF: Time-of-Flight). As a method for detecting the light L2 emitted from the light emitting device 2001 by the light detector 2002, for example, a structured light method or a stereoscopic vision method can be used. For example, in the structured light method, the distance between the light detection system 2000 and the object 2100 can be measured by projecting a predetermined pattern of light onto the object 2100 and analyzing the degree of distortion of the pattern. In addition, in the stereoscopic vision method, the distance between the light detection system 2000 and the object 2100 can be measured by, for example, using two or more cameras to obtain two or more images observed from two or more different viewpoints of the object 2100. It should be noted that the light emitting device 2001 and the light detector 2002 can be synchronously controlled by the system controller 2003. [6. Actual application examples] [Examples of practical applications in mobile objects]

[0079] The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure can be implemented as a device installed on any type of mobile body such as a vehicle, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility device, an airplane, a drone, a ship, a robot, a construction machine, or an agricultural machine (tractor).

[0080] Fig.13 : is a block diagram depicting an example of a schematic configuration of a vehicle control system as an example of a moving body control system to which the technology according to the embodiment of the present disclosure can be applied.

[0081] The vehicle control system 12000 includes a plurality of electronic control units interconnected via a communication network 12001. Fig.13 In the example shown, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside information detection unit 12030, an inside information detection unit 12040, and an integrated control unit 12050. In addition, as a functional configuration of the integrated control unit 12050, a microcomputer 12051, a sound / image output section 12052, and an in-vehicle network interface (I / F) 12053 are shown.

[0082] The drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various programs. For example, the drive system control unit 12010 serves as a control device for a drive force generating device (e.g., an internal combustion engine, a drive motor, etc.) for generating a drive force for the vehicle, a drive force transmitting mechanism for transmitting a drive force to wheels, a steering mechanism for adjusting a steering angle of the vehicle, a braking device for generating a braking force for the vehicle, and the like.

[0083] The body system control unit 12020 controls the operation of various devices provided in the body according to various programs. For example, the body system control unit 12020 is used as a control device for a keyless entry system, a smart key system, a power window device, or various lights (e.g., headlights, reverse lights, brake lights, turn signals, fog lights, etc.). In this case, radio waves emitted from a mobile device as a substitute for a key or signals of various switches may be input to the body system control unit 12020. The body system control unit 12020 receives these input radio waves or signals, and controls the door lock device, power window device, lights, etc. of the vehicle.

[0084] The vehicle exterior information detection unit 12030 detects information of the exterior of the vehicle including the vehicle control system 12000. For example, the vehicle exterior information detection unit 12030 is connected to the camera unit 12031. The vehicle exterior information detection unit 12030 causes the camera unit 12031 to capture an image of the exterior of the vehicle and receives the captured image. Based on the received image, the vehicle exterior information detection unit 12030 can perform a process of detecting an object such as a person, a vehicle, an obstacle, a sign, a text on the road, or a process of detecting a distance therefrom.

[0085] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as information related to the measured distance. In addition, the light received by the imaging unit 12031 can be visible light or invisible light such as infrared light.

[0086] The in-vehicle information detection unit 12040 detects information about the interior of the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver state detection unit 12041 that detects the state of the driver. The driver state detection unit 12041 includes, for example, a camera that images the driver. 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 can determine whether the driver is dozing off.

[0087] The microcomputer 12051 can calculate the control target value of the driving force generation device, the steering mechanism or the braking device based on the information about the inside or outside of the vehicle obtained by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, and output a control command to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control to realize the functions of an advanced driver assistance system (ADAS) including collision avoidance or collision mitigation of the vehicle, following driving based on a following distance, speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0088] In addition, the microcomputer 12051 can perform collaborative control by controlling the driving force generating device, steering mechanism, braking device, etc. according to the information about the outside or inside of the vehicle obtained by the outside information detection unit 12030 or the inside information detection unit 12040, so as to realize automatic driving that allows the vehicle to drive autonomously without relying on the driver's operation.

[0089] In addition, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information about the exterior of the vehicle obtained by the exterior information detection unit 12030. For example, the microcomputer 12051 can perform cooperative control aimed at preventing glare by controlling the headlights to change from high beam to low beam based on the position of the preceding vehicle or the oncoming vehicle detected by the exterior information detection unit 12030.

[0090] The sound / image output unit 12052 transmits an output signal of at least one of sound and image to an output device capable of notifying the vehicle occupants or the outside of the vehicle of information in a visual or auditory manner. Fig.13 In the example of FIG. 1 , as the output device, an audio speaker 12061, a display portion 12062, and an instrument panel 12063 are shown. The display portion 12062 may include, for example, at least one of an in-vehicle display and a head-up display.

[0091] Fig.14 This is a diagram illustrating an example of the installation position of the camera unit 12031.

[0092] exist Fig.14 In the figure, the camera unit 12031 includes camera units 12101, 12102, 12103, 12104 and 12105.

[0093] Camera units 12101, 12102, 12103, 12104 and 12105 are arranged, for example, at the front nose, rearview mirror, rear bumper and rear door of the vehicle 12100 and at the upper part of the windshield in the vehicle. The camera unit 12101 arranged at the front nose and the camera unit 12105 arranged at the upper part of the windshield in the vehicle mainly obtain images in front of the vehicle 12100. The camera units 12102 and 12103 arranged at the rearview mirror mainly obtain images of the side of the vehicle 12100. The camera unit 12104 arranged at the rear bumper or rear door mainly obtains images of the rear of the vehicle 12100. The camera unit 12105 arranged at the upper part of the windshield in the vehicle is mainly used to detect vehicles in front, pedestrians, obstacles, signals, traffic signs, lanes, etc.

[0094] By the way, Fig.14 An example of the photographing range of the camera units 12101 to 12104 is depicted. The photographing range 12111 indicates the photographing range of the camera unit 12101 provided at the front nose. The photographing ranges 12112 and 12113 respectively indicate the photographing ranges of the camera units 12102 and 12103 provided at the rearview mirror. The photographing range 12114 indicates the photographing range of the camera unit 12104 provided at the rear bumper or the rear door. For example, by superimposing the image data photographed by the camera units 12101 to 12104, a bird's-eye view image of the vehicle 12100 seen from above is obtained.

[0095] At least one of the imaging units 12101 to 12104 may have a function of obtaining distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.

[0096] For example, the microcomputer 12051 can determine the distance to each three-dimensional object within the shooting ranges 12111 to 12114 and the time change of these distances (relative speed with respect to the vehicle 12100) based on the distance information obtained from the camera units 12101 to 12104, thereby extracting the nearest three-dimensional object, in particular, the nearest three-dimensional object that exists on the driving path of the vehicle 12100 and travels in the same direction as the vehicle 12100 at a predetermined speed (e.g., equal to or greater than 0 km / h) as the front vehicle. In addition, the microcomputer 12051 can pre-set the following distance to be maintained with the front vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. Therefore, cooperative control of automatic driving aimed at autonomous driving without relying on the operation of the driver, etc. can be performed.

[0097] For example, the microcomputer 12051 can classify the three-dimensional object data about the three-dimensional object into three-dimensional object data of two-wheeled vehicles, standard-sized vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on the distance information obtained from the camera units 12101 to 12104, extract the classified three-dimensional object data, and use the extracted three-dimensional object data to automatically avoid obstacles. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 as obstacles that can be visually recognized by the driver of the vehicle 12100 and obstacles that are difficult for the driver of the vehicle 12100 to visually recognize. Then, the microcomputer 12051 determines the collision risk representing the risk of collision with each obstacle. When the collision risk is equal to or higher than the set value and there is a possibility of collision, the microcomputer 12051 outputs a warning to the driver through the audio speaker 12061 or the display unit 12062, and performs forced deceleration or evasive steering through the drive system control unit 12010. Therefore, the microcomputer 12051 can assist driving to avoid collision.

[0098] At least one of the camera units 12101 to 12104 may be an infrared camera that detects infrared rays. The microcomputer 12051 may identify a pedestrian, for example, by determining whether a pedestrian exists in the captured images of the camera units 12101 to 12104. This recognition of pedestrians is performed, for example, by extracting feature points in the captured images of the camera units 12101 to 12104 as infrared cameras, and determining whether the object is a pedestrian by pattern matching a series of feature points representing the contour of the object. When the microcomputer 12051 determines that a pedestrian exists in the captured images of the camera units 12101 to 12104 and thus identifies the pedestrian, the sound / image output unit 12052 controls the display unit 12062 so as to display a quadrilateral contour line for emphasis in a manner superimposed on the recognized pedestrian. The sound / image output unit 12052 may also control the display unit 12062 so that an icon representing a pedestrian or the like is displayed at a desired position.

[0099] Although the description has been made with reference to the first to third embodiments, modifications, application examples, and practical application examples, the contents of the present disclosure are not limited to the above-mentioned embodiments, etc. For example, in the above-mentioned embodiments, etc., the present technology is described as using a unit pixel P having a rectangular shape; however, the shape of the unit pixel P is not limited to a rectangular shape. For example, the unit pixel P may have a polygonal shape such as an octagonal shape. In this case, by providing a contact layer 15 at each corner and electrically connecting the contact layer 15 to the opening 191H of the polysilicon film 192, a similar effect can be achieved.

[0100] In addition, the photodetector of the present disclosure does not necessarily include all the components described in the above embodiments, etc., and may include other layers. For example, when the photodetector 1 is to detect light other than visible light (e.g., near infrared light (IR)), the color filter 32 may be omitted.

[0101] Furthermore, the polarity of the semiconductor region constituting the photodetector according to the present disclosure may be reversed. Furthermore, in the photodetector according to the present disclosure, holes may be used as signal charges.

[0102] Furthermore, as long as the photodetector according to the present disclosure is in a state where avalanche multiplication occurs by applying a reverse bias between the anode and the cathode, the respective potentials are not limited.

[0103] Furthermore, the above-described embodiments and the like exemplify the semiconductor substrate 11 including silicon; however, the semiconductor substrate 11 may include, for example, germanium (Ge) or a composite semiconductor of silicon (Si) and germanium (Ge) (eg, silicon germanium (SiGe)).

[0104] It should be understood that the effects described herein are merely examples, and the present disclosure may include any effects other than the effects described herein, or may also include other effects other than the effects described herein.

[0105] It should be noted that the present disclosure may have the following configuration. According to the present technology having the following configuration, it is possible to prevent the entry of leakage light from adjacent pixels, and ensure the distance between the anode for applying voltage to the light receiving unit and the cathode for applying voltage to the multiplication unit. Therefore, it is possible to improve the voltage resistance to edge breakdown while suppressing crosstalk. (1) A light detector comprising: a first semiconductor substrate having a first surface and a second surface facing each other and including a pixel array section in which a plurality of pixels are arranged in an array in an in-plane direction; a light receiving section which is provided inside the first semiconductor substrate for each of the pixels and generates carriers corresponding to the amount of received light by photoelectric conversion; a multiplication section provided on the first surface for each of the pixels and avalanche multiplying the carriers generated in the light receiving section; an insulating layer stacked on the first surface, the insulating layer having one or more openings disposed at predetermined positions; one or more polysilicon films provided at least along a boundary of the pixels adjacent to each other on the first face side, the insulating layer interposed between the first face and the one or more polysilicon films, and the one or more polysilicon films being electrically connected to at least the light receiving portion through the one or more openings; one or more first wirings provided along the outer shape of the pixel on the first surface side; and One or more first connection wirings are provided along the outer shape of the pixel on the first surface side and electrically connect the one or more polysilicon films and the one or more first wirings to each other. (2) The photodetector according to (1), wherein the one or more polysilicon films, the one or more first wirings, and the one or more first connection wirings are respectively formed continuously along boundaries of the pixels adjacent to each other. (3) The photodetector according to (1) or (2), wherein: Each of the plurality of pixels has a polygonal planar shape, and The one or more openings are disposed at a corner of each of the plurality of pixels. (4) The photodetector according to any one of (1) to (3), wherein Each of the plurality of pixels has a rectangular planar shape, and The one or more polysilicon films and the light receiving section are electrically connected to each other through the one or more openings, and the one or more openings are provided at four corners of each of the pixels. (5) The photodetector according to any one of (1) to (4), further comprising: A pixel isolation portion is provided between the plurality of pixels adjacent to each other so as to extend from the first surface to the second surface and electrically isolates the plurality of pixels adjacent to each other. (6) The optical detector according to (5), further comprising: a plurality of first contact layers which are arranged on the first surface along the pixel isolation portion and are electrically connected to the light receiving portion, The one or more polysilicon films disposed along the boundary between adjacent pixels are electrically connected to the light receiving portion through the plurality of first contact layers. (7) The photodetector according to (6), wherein Each of the plurality of pixels has a polygonal planar shape, and The plurality of first contact layers are disposed at a corner of each of the plurality of pixels. (8) The photodetector according to (6) or (7), wherein: Each of the plurality of pixels has a rectangular planar shape, and The plurality of first contact layers are disposed at four corners of each of the pixels. (9) The photodetector according to any one of (1) to (8), further comprising: a second contact layer disposed approximately at the center of the pixel on the first face and electrically connected to the multiplication section, wherein one of the one or more openings is disposed on the second contact layer, and One of the one or more polysilicon films is electrically connected to the multiplication portion through the second contact layer. (10) The photodetector according to any one of (1) to (9), further comprising: a second contact layer disposed at an approximate center of the pixel on the first face and electrically connected to the multiplication section; a second wiring provided in a wiring layer including the one or more first wirings; and a second connecting wiring which electrically connects the second contact layer and the second wiring to each other, wherein one of the one or more openings is disposed on the second contact layer, and The second connection wiring is directly electrically connected to the second contact layer without passing through the one or more polysilicon films. (11) The photodetector according to any one of (1) to (10), further comprising: a multilayer wiring layer having the one or more first wirings and the one or more first connecting wirings; and A second semiconductor substrate is arranged between the first surface and the multi-layer wiring layer, wherein the one or more first connecting wirings pass through the second semiconductor substrate. (12) The photodetector according to (11), wherein the second semiconductor substrate is provided with a plurality of transistors constituting a readout circuit that outputs a pixel signal based on the charge output from each of the plurality of pixels. (13) The photodetector according to any one of (1) to (12), wherein the first connection wiring is formed using tungsten, aluminum, copper, cobalt, nickel, titanium, or a silicon compound thereof. (14) A distance measuring device comprising: Optical system; a light detector; and a signal processing circuit for calculating the distance to a measurement target based on an output signal of the light detector, Wherein, the light detector comprises: a first semiconductor substrate having a first surface and a second surface facing each other and including a pixel array section in which a plurality of pixels are arranged in an array in an in-plane direction; a light receiving section which is provided inside the first semiconductor substrate for each of the pixels and generates carriers corresponding to the amount of received light by photoelectric conversion; a multiplication section provided on the first surface for each of the pixels and avalanche multiplying the carriers generated in the light receiving section; an insulating layer stacked on the first surface, the insulating layer having one or more openings disposed at predetermined positions; one or more polysilicon films provided at least along a boundary of the pixels adjacent to each other on the first face side, the insulating layer interposed between the first face and the one or more polysilicon films, and the one or more polysilicon films being electrically connected to at least the light receiving portion through the one or more openings; one or more first wirings provided along the outer shape of the pixel on the first surface side; and One or more first connection wirings are provided along the outer shape of the pixel on the first surface side and electrically connect the one or more polysilicon films and the one or more first wirings to each other.

[0106] This application claims the benefit of Japanese Priority Patent Application JP2022-140195 filed in the Japan Patent Office on September 2, 2022, the entire contents of which are incorporated herein by reference.

[0107] It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims

1. A light detector comprising: A first semiconductor substrate having a first surface and a second surface facing each other and including a pixel array section in which a plurality of pixels are arranged in an array in an in-plane direction; a light receiving section which is provided inside the first semiconductor substrate for each of the pixels and generates carriers corresponding to the amount of received light by photoelectric conversion; a multiplication section provided on the first surface for each of the pixels and avalanche multiplying the carriers generated in the light receiving section; an insulating layer stacked on the first surface, the insulating layer having one or more openings disposed at predetermined positions; one or more polysilicon films provided at least along a boundary of the pixels adjacent to each other on the first face side, the insulating layer interposed between the first face and the one or more polysilicon films, and the one or more polysilicon films being electrically connected to at least the light receiving portion through the one or more openings; One or more first wirings arranged along the outer shape of the pixel on the first surface side; as well as One or more first connection wirings are provided along the outer shape of the pixel on the first surface side and electrically connect the one or more polysilicon films and the one or more first wirings to each other.

2. The optical detector according to claim 1, wherein The one or more polysilicon films, the one or more first wirings, and the one or more first connection wirings are respectively formed continuously along boundaries of the pixels adjacent to each other.

3. The light detector according to claim 1, wherein Each of the plurality of pixels has a polygonal planar shape, and The one or more openings are disposed at a corner of each of the plurality of pixels.

4. The light detector according to claim 1, wherein Each of the plurality of pixels has a rectangular planar shape, and The one or more polysilicon films and the light receiving section are electrically connected to each other through the one or more openings, and the one or more openings are provided at four corners of each of the pixels.

5. The light detector according to claim 1, further comprising: A pixel isolation portion is provided between the plurality of pixels adjacent to each other so as to extend from the first surface to the second surface and electrically isolates the plurality of pixels adjacent to each other.

6. The light detector according to claim 5, further comprising: a plurality of first contact layers which are arranged on the first surface along the pixel isolation portion and are electrically connected to the light receiving portion, The one or more polysilicon films disposed along the boundary between adjacent pixels are electrically connected to the light receiving portion through the plurality of first contact layers.

7. The light detector according to claim 6, wherein Each of the plurality of pixels has a polygonal planar shape, and The plurality of first contact layers are disposed at a corner of each of the plurality of pixels.

8. The light detector according to claim 6, wherein Each of the plurality of pixels has a rectangular planar shape, and The plurality of first contact layers are disposed at four corners of each of the pixels.

9. The light detector according to claim 1, further comprising: a second contact layer disposed approximately at the center of the pixel on the first face and electrically connected to the multiplication section, wherein one of the one or more openings is disposed on the second contact layer, and One of the one or more polysilicon films is electrically connected to the multiplication portion through the second contact layer.

10. The light detector according to claim 1, further comprising: a second contact layer disposed at an approximate center of the pixel on the first face and electrically connected to the multiplication section; a second wiring line disposed in a wiring layer, the wiring layer including the one or more first wiring lines; as well as a second connecting wiring which electrically connects the second contact layer and the second wiring to each other, wherein one of the one or more openings is disposed on the second contact layer, and The second connection wiring is directly electrically connected to the second contact layer without passing through the one or more polysilicon films.

11. The light detector according to claim 1, further comprising: a multilayer wiring layer having the one or more first wirings and the one or more first connecting wirings; as well as a second semiconductor substrate disposed between the first surface and the multilayer wiring layer, The one or more first connecting wires pass through the second semiconductor substrate.

12. The optical detector according to claim 11, wherein The second semiconductor substrate is provided with a plurality of transistors constituting a readout circuit that outputs a pixel signal based on the charge output from each of the plurality of pixels.

13. The light detector according to claim 1, wherein The first connection wiring is formed using tungsten, aluminum, copper, cobalt, nickel, titanium, or a silicon compound thereof.

14. A distance measuring device, comprising: Optical system; Light detector; as well as a signal processing circuit for calculating the distance to a measurement target based on an output signal of the light detector, Wherein, the light detector comprises: a first semiconductor substrate having a first surface and a second surface facing each other and including a pixel array section in which a plurality of pixels are arranged in an array in an in-plane direction; a light receiving section which is provided inside the first semiconductor substrate for each of the pixels and generates carriers corresponding to the amount of received light by photoelectric conversion; a multiplication section provided on the first surface for each of the pixels and avalanche multiplying the carriers generated in the light receiving section; an insulating layer stacked on the first surface, the insulating layer having one or more openings disposed at predetermined positions; one or more polysilicon films provided at least along a boundary of the pixels adjacent to each other on the first face side, the insulating layer interposed between the first face and the one or more polysilicon films, and the one or more polysilicon films being electrically connected to at least the light receiving portion through the one or more openings; one or more first wirings provided along the outer shape of the pixel on the first surface side; and One or more first connection wirings are provided along the outer shape of the pixel on the first surface side and electrically connect the one or more polysilicon films and the one or more first wirings to each other.

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