Light detection device and distance measuring device

Abstract

A light detection device according to an embodiment of the present disclosure is provided with: a semiconductor substrate having a first surface and a second surface opposite each other, and including a pixel array section in which a plurality of pixels are arranged in an array; a semiconductor layer provided on the first surface side of the semiconductor substrate; a light receiving section which is provided in the semiconductor substrate for each pixel and that generates, by photoelectric conversion, a carrier corresponding to an amount of light received; a multiplier section comprising a first conductivity-type region and a second conductivity-type region stacked in order on the first surface side, at least the second conductivity-type region being provided in the semiconductor layer, the multiplier section avalanche-multiplying the carrier generated in the light receiving section; a first electrode provided on the first surface side and electrically connected to the light receiving section; and a second electrode provided on the first surface side and electrically connected to the multiplier section.

Description

Technical Field

[0001] The present disclosure relates to, for example, a light detection device using an avalanche photodiode and a distance measurement device including the same.

Background Art

[0002] For example, Patent Document 1 discloses a photodetector in which an avalanche photodiode is provided for each pixel and a semiconductor region surrounding the avalanche photodiode is provided to separate adjacent pixels.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] By the way, in the light detection device constituting the distance measurement device, suppression of unintentional edge breakdown is required.

[0005]

[0006] The semiconductor substrate further has an insulating layer on the first surface side, and the semiconductor layer is embedded in the insulating layer for each pixel, and further has a reflective layer provided within the insulating layer and surrounding the semiconductor layer. A light detection device according to an embodiment of the present disclosure includes a semiconductor substrate having opposing first and second surfaces and a pixel array portion in which a plurality of pixels are arranged in an array, a semiconductor layer provided on the first surface side of the semiconductor substrate, a light receiving portion provided inside the semiconductor substrate for each pixel and generating carriers corresponding to the amount of received light by photoelectric conversion, a first conductivity type region and a second conductivity type region laminated in order on the first surface side, at least the second conductivity type region being provided in the semiconductor layer, a multiplication portion that multiplies the carriers generated in the light receiving portion by avalanche multiplication, a first electrode provided on the first surface side and electrically connected to the light receiving portion, and a second electrode provided on the first surface side and electrically connected to the multiplication portion. The semiconductor substrate further has an insulating layer on the first surface side, and the semiconductor layer is embedded in the insulating layer for each pixel, and further has a reflective layer provided within the insulating layer and surrounding the semiconductor layer. .

[0007] A distance measuring device according to one embodiment of the present disclosure comprises an optical system, a light detection device, and a signal processing circuit that calculates the distance to an object to be measured from the output signal of the light detection device, wherein the light detection device is the light detection device according to the present disclosure described above.

[0008] In one embodiment of the optical detection device and one embodiment of the distance measuring device of the present disclosure, a semiconductor layer is provided on the first surface side of a semiconductor substrate having opposing first and second surfaces, and at least the second conductivity type region of the first and second conductivity type regions constituting the multiplication section is provided within the semiconductor layer. This ensures a distance between the first electrode electrically connected to the light receiving section and the second conductivity type region constituting the multiplication section. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to an embodiment of the present disclosure. [Figure 2] Figure 1 is a block diagram showing an example of a schematic configuration of the photodetector shown. [Figure 3] Figure 1 shows an example of an equivalent circuit diagram for a unit pixel of the photodetector. [Figure 4] This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 1 of this disclosure. [Figure 5] This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 2 of this disclosure. [Figure 6A] Figure 5 is a schematic diagram illustrating an example of the planar shape of the semiconductor layer in a unit pixel of the photodetector shown. [Figure 6B] Figure 5 is a schematic diagram illustrating another example of the planar shape of the semiconductor layer in a unit pixel of the photodetector shown in Figure 5. [Figure 6C] Figure 5 is a schematic diagram illustrating another example of the planar shape of the semiconductor layer in a unit pixel of the photodetector shown in Figure 5. [Figure 7] This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 3 of this disclosure. [Figure 8]This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 4 of this disclosure. [Figure 9] This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 5 of the present disclosure. [Figure 10] This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 6 of this disclosure. [Figure 11] This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 7 of this disclosure. [Figure 12] This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 8 of this disclosure. [Figure 13] Figure 12 is a schematic planar diagram showing an example of the planar layout of the p-type and n-type semiconductor regions in a unit pixel of the photodetector. [Figure 14] This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 9 of this disclosure. [Figure 15] Figure 14 is a schematic plan view illustrating an example of the layout of the reflective layer in a unit pixel of the photodetector shown. [Figure 16] This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 10 of this disclosure. [Figure 17] Figure 16 is a schematic plan view showing an example of the wiring layout for the reflective layer at a unit pixel of the photodetector shown. [Figure 18] This is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 11 of the present disclosure. [Figure 19] This is a functional block diagram illustrating an example of an electronic device using the photodetector shown in Figure 1, etc. [Figure 20] This block diagram shows an example of a schematic configuration of a vehicle control system. [Figure 21] This is an explanatory diagram showing an example of the installation location of the external information detection unit and the imaging unit. [Modes for carrying out the invention]

[0010] The embodiments described below will be explained in detail with reference to the drawings. The following description is one specific example of the disclosure, and the disclosure is not limited to the following embodiments. Furthermore, the disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc., of each component shown in each drawing. The order of explanation is as follows. 1. Embodiment (A photodetector in which the n-type semiconductor region constituting the multiplication section is provided within a semiconductor layer on a semiconductor substrate.) 1-1. Configuration of the photodetector 1-2. Method for manufacturing a photodetector 1-3. Action and Effects 2. Variations 2-1. Variation 1 (An example in which n-type semiconductor regions and p-type semiconductor regions constituting the multiplication section are provided in the semiconductor layer) 2-2. Variation 2 (An example in which a semiconductor layer is provided for each pixel, and an insulating layer is provided around it.) 2-3. Variation 3 (An example in which n-type semiconductor regions and p-type semiconductor regions constituting the multiplication section are provided in a semiconductor layer for each pixel.) 2-4. Variation 4 (Example where the pixel separation portion protrudes into the semiconductor layer) 2-5. Variation 5 (Example where the side surface of the semiconductor layer is sloped) 2-6. Variation 6 (An example in which an n-type semiconductor region constituting the multiplication area is provided inside the side surface of the semiconductor layer.) 2-7. Variation 7 (An example in which n-type and p-type semiconductor regions constituting the multiplication area are provided inside the side surface of the semiconductor layer.) 2-8. Variation 8 (An example in which multiple n-type semiconductor regions constituting a multiplication zone are provided within a semiconductor layer) 2-9. Variation 9 (An example in which a reflective layer is provided within the insulating layer surrounding the semiconductor layer.) 2-10. Variation 10 (Example of using a reflective layer as a resistive element in a readout circuit) 2-11. Variation 11 (Example where wiring within a multilayer wiring layer is used as a reflective layer) 3. Examples of application 4. Application Examples

[0011] <1. Embodiment> Figure 1 schematically shows an example of a cross-sectional configuration of a photodetector (photodetector 1) according to one embodiment of the present disclosure. Figure 2 is a block diagram showing the schematic configuration of the photodetector 1 shown in Figure 1, and Figure 3 shows an example of an equivalent circuit of a unit pixel P of the photodetector 1 shown in Figure 1. The photodetector 1 is applied, for example, to distance image sensors (distance image device 1000 described later, see Figure 19) and image sensors that measure distance using the ToF (Time-of-Flight) method.

[0012] (1-1. Configuration of the photodetector) The photodetector 1 has, for example, a pixel array section 100A in which multiple unit pixels P are arranged in an array in the row and column directions. As shown in Figure 2, the photodetector 1 has a bias voltage application section 110 together with the pixel array section 100A. The bias voltage application section 110 applies a bias voltage to each unit pixel P of the pixel array section 100A. In this embodiment, the case in which electrons are read out as signal charges will be described.

[0013] As shown in Figure 3, a unit pixel P comprises a photodetector 12, a quenching resistor element 120 made of a p-type MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), and an inverter 130 made of, for example, a complementary type MOSFET.

[0014] The light-receiving element 12 converts incident light into an electrical signal by photoelectric conversion and outputs it. Incidentally, the light-receiving element 12 converts incident light (photons) into an electrical signal by photoelectric conversion and outputs a pulse corresponding to the incident photons. The light-receiving element 12 is, for example, a SPAD element, and the SPAD element has the characteristic that, for example, when a large negative voltage is applied to the cathode, an avalanche multiplication region (depletion layer) 12X is formed, and electrons generated in response to the incident 1 photon undergo avalanche multiplication, causing a large current to flow. The light-receiving element 12 has, for example, an anode connected to a bias voltage application unit 110 and a cathode connected to the source terminal of a quenching resistor element 120. The anode of the light-receiving element 12 is supplied with a device voltage V from the device voltage application unit. B It is applied.

[0015] The quenching resistor element 120 is connected in series with the photodetector element 12, with its source terminal connected to the cathode of the photodetector element 12 and its drain terminal connected to a power supply (not shown). An excitation voltage V is supplied from the power supply to the drain terminal of the quenching resistor element 120. E A voltage is applied. The quenching resistor element 120 is subjected to a negative voltage V due to the voltage generated by electrons avalanche multiplied by the photodetector element 12. BD When it reaches this point, the photodetector 12 emits electrons that have been multiplied, performing quenching to return the voltage to its initial voltage.

[0016] The inverter 130 has input terminals connected to the cathode of the photodetector 12 and the source terminal of the quenching resistor element 120, and output terminals connected to a subsequent arithmetic processing unit (not shown). The inverter 130 outputs a photodetected signal based on the carriers (signal charges) multiplied by the photodetector 12. More specifically, the inverter 130 shapes the voltage generated by the electrons multiplied by the photodetector 12. The inverter 130 then outputs a photodetected signal (APD OUT) to the arithmetic processing unit, starting from the arrival time of one font, generating a pulse waveform, for example, as shown in Figure 3. For example, the arithmetic processing unit performs calculations to determine the distance to the subject based on the timing of the pulse indicating the arrival time of one font in each photodetected signal, and calculates the distance for each unit pixel P. Based on these distances, a distance image is generated by arranging the distances to the subject detected by multiple unit pixels P in a planar manner.

[0017] The light detection device 1 is a so-called back-illuminated light detection device in which a logic board 20 is laminated on the surface side of the sensor substrate 10 (for example, the surface side (first surface 11S1) of the semiconductor substrate 11 constituting the sensor substrate 10), and light is received from the back side of the sensor substrate 10 (for example, the back side (second surface 11S2) of the semiconductor substrate 11 constituting the sensor substrate 10). The light detection device 1 of this embodiment has a light-receiving element 12 for each unit pixel P. The light-receiving element 12 has a light-receiving portion 13 and a multiplier portion 14, and the light-receiving portion 13 is embedded in the semiconductor substrate 11. The semiconductor substrate 11 further has a p-type semiconductor region (p) constituting the multiplier portion 14 on the first surface 11S1. + )14X and n-type semiconductor region (n + ) The p-type semiconductor region of 14Y (p + A 14X is provided. A semiconductor layer 15 is provided on the first surface 11S1 side of the semiconductor substrate 11, and an n-type semiconductor region (n + )14Y is provided.

[0018] In the diagrams, the symbols "p" and "n" represent the p-type and n-type semiconductor regions, respectively. Furthermore, the "+" or "-" at the end of "p" both represent the impurity concentration in the p-type semiconductor region. Similarly, the "+" or "-" at the end of "n" both represent the impurity concentration in the n-type semiconductor region. Here, a higher number of "+" signs indicates a higher impurity concentration, and a higher number of "-" signs indicates a lower impurity concentration. This also applies to subsequent diagrams.

[0019] The sensor substrate 10 includes, for example, a semiconductor substrate 11 made of a silicon substrate, a semiconductor layer 15, and a multilayer wiring layer 18. The semiconductor substrate 11 has opposing first surfaces 11S1 and second surfaces 11S2. The semiconductor substrate 11 has a common p-well (p) 111 for a plurality of unit pixels P. The semiconductor substrate 11 is provided with an n-type semiconductor region (n) 112 for each unit pixel P, for example, an n-type semiconductor region with controlled impurity concentration, thereby forming a light-receiving element 12 for each unit pixel P. The semiconductor substrate 11 is further provided with a pixel separation portion 17 extending between the first surface 1S1 and the second surface 11S2.

[0020] The photodetector 12 has a multiplication region (avalanche multiplication region) that multiplies carriers by a high electric field region. As described above, by applying a large positive voltage to the cathode, an avalanche multiplication region (depletion layer) is formed, and the SPAD element is capable of multiplying electrons generated by the incidence of one photon by avalanche.

[0021] The light-receiving element 12 consists of a light-receiving section 13 and a light-multiplier section 14.

[0022] The light-receiving portion 13 corresponds to a specific example of the "light-receiving portion" of the present disclosure, and has a photoelectric conversion function of absorbing light incident from the second surface 11S2 side of the semiconductor substrate 11 and generating carriers according to the amount of received light. As described above, the light-receiving portion 13 is configured to include an n-type semiconductor region (n) 112 in which the impurity concentration is controlled to be n-type. The carriers (electrons) generated in the light-receiving portion 13 are transferred to the multiplication portion 14 by the potential gradient.

[0023] The multiplication portion 14 corresponds to a specific example of the "multiplication portion" of the present disclosure, and avalanche multiplies the carriers (here, electrons) generated in the light-receiving portion 13. The multiplication portion 14 includes, for example, a p-type semiconductor region (p + ) 14X having a higher impurity concentration than the p-well (p) 111, and an n-type semiconductor region (n + ) 14Y having a higher impurity concentration than the n-type semiconductor region (n) 112. The p-type semiconductor region (p + ) 14X is provided in the semiconductor substrate 11 facing the first surface 11S1. The n-type semiconductor region (n + ) 14Y is provided protruding from the first surface 11S1 of the semiconductor substrate 11. Specifically, as described above, it is embedded and formed in the semiconductor layer 15 provided on the first surface of the semiconductor substrate 11 facing the second surface 15S2 of the semiconductor layer 15.

[0024] In the light-receiving element 12, an avalanche multiplication region 12X is formed at the junction between the p-type semiconductor region (p + ) 14X provided facing the first surface 11S1 of the semiconductor substrate 11 and the n-type semiconductor region (n + ) 14Y provided facing the second surface 15S2 of the semiconductor layer 15. The avalanche multiplication region 12X is a high electric field region (depletion layer) formed at the interface between the p-type semiconductor region (p + ) 14X and the n-type semiconductor region (n + ) 14Y by a large negative voltage applied to the cathode. In the avalanche multiplication region 12X, the electrons (e - ) generated by 1 photon incident on the light-receiving element 12 are multiplied.

[0025] The semiconductor layer 15 is a semiconductor layer made of, for example, silicon, formed on the first surface 11S1 of the semiconductor substrate 11 using, for example, an epitaxial crystal growth method, and corresponds to one specific example of the "semiconductor layer" of this disclosure. The semiconductor layer 15 has opposing first surface 15S1 and second surface 15S2. The first surface 15S1 faces the multilayer wiring layer 18, and the second surface 15S2 faces the semiconductor substrate 11. As described above, the semiconductor layer 15 has an n-type semiconductor region (n + )14Y is embedded and formed.

[0026] The semiconductor layer 15 further includes a cathode, which corresponds to a specific example of the "second electrode" of this disclosure, and a contact electrode 16 for electrically connecting the multiplication unit 14, in an n-type semiconductor region (n + )14Y is provided facing the first surface 15S1. The contact electrode 16 is, for example, an n-type semiconductor region (n + )n-type semiconductor region with higher impurity concentration than 14Y (n ++ It is composed of ).

[0027] The pixel separation section 17 electrically and / or optically separates adjacent unit pixels P and is provided, for example, in a grid pattern on the pixel array section 100A. The pixel separation section 17 is composed of, for example, a light-shielding film 17A extending between the first surface 11S1 and the second surface 11S2 of the semiconductor substrate 11, and insulating films 17B and 17C provided between the light-shielding film 17A and the semiconductor substrate 11. The light-shielding film 17A has a light-shielding section 17X that is extended and formed on the second surface 11S2 of the semiconductor substrate 11. The light-shielding section 17X suppresses crosstalk of obliquely incident light between adjacent unit pixels P. The light-shielding film 17A and the light-shielding section 17X are formed using, for example, a conductive material with light-shielding properties. Examples of such materials include tungsten (W), silver (Ag), copper (Cu), aluminum (Al), or an alloy of Al and copper (Cu). Insulating films 17B and 17C are, for example, silicon oxide (SiO2). x ) It is formed using a membrane or the like.

[0028] Around the pixel separation area 17, there is a p-type semiconductor region (p) with a higher impurity concentration than the p-well 111. + )113 is provided. p-type semiconductor region (p + )113 extends inward toward the unit pixel P near the first surface 11S1 of the semiconductor substrate 11 (extension portion 113X). This extension portion 113X also serves as a contact electrode that electrically connects the anode, which corresponds to one specific example of the "first electrode" of this disclosure, and the light receiving portion 13. p-type semiconductor region (p + )113 further extends in the vicinity of the second surface 11S2 of the semiconductor substrate 11, for example, over the pixel array portion 100A.

[0029] On the first surface 11S1 side of the semiconductor substrate 11, opposite to the light incident surface (second surface 11S2), a multilayer wiring layer 18 is provided with a semiconductor layer 15 in between. In the multilayer wiring layer 18, one or more wiring layers 181 are formed within the interlayer insulating layer 182. The wiring layers 181 are used, for example, to supply voltage to be applied to the semiconductor substrate 11 or the photodetector 12, or to extract carriers generated in the photodetector 12. Some of the wiring in the wiring layer 181 is electrically connected to the contact electrode 16 and the extension portion 113X via via V1. Multiple pad electrodes 183 are embedded in the surface of the interlayer insulating layer 182 opposite to the semiconductor substrate 11 side (the surface 18S1 of the multilayer wiring layer 18). The multiple pad electrodes 183 are electrically connected to some of the wiring in the wiring layer 181 via via V2. Although Figure 1 shows an example in which one wiring layer 181 is formed within the multilayer wiring layer 18, the total number of wiring layers within the multilayer wiring layer 18 is not limited, and two or more wiring layers may be formed.

[0030] The interlayer insulating layer 182 is, for example, silicon oxide (SiO x ), TEOS, silicon nitride (SiN x ) and silicon oxynitride (SiO x N y It is composed of a single layer film made of one of the following, or a laminated film made of two or more of these.

[0031] The wiring layer 181 is formed using, for example, aluminum (Al), copper (Cu), or tungsten (W).

[0032] The pad electrode 183 is exposed on the junction surface with the logic board 20 (the surface 18S1 of the multilayer wiring layer 18) and is used, for example, for connection with the logic board 20. The pad electrode 183 is formed using, for example, copper (Cu).

[0033] The logic board 20 includes, for example, a semiconductor substrate 21 made of a silicon substrate and a multilayer wiring layer 22. The logic board 20 includes logic circuits such as the bias voltage application unit 110 described above, a readout circuit that outputs a pixel signal based on the charge output from the unit pixel P of the pixel array unit 100A, a vertical drive circuit, a column signal processing circuit, a horizontal drive circuit, and an output circuit.

[0034] The multilayer wiring layer 22 consists of, for example, the gate wiring 221 of a transistor constituting a readout circuit, and wiring layers 222, 223, 224, and 225 containing one or more wirings, which are stacked sequentially from the semiconductor substrate 21 side with an interlayer insulating layer 226 in between. Multiple pad electrodes 227 are embedded in the surface of the interlayer insulating layer 226 opposite to the semiconductor substrate 21 side (the surface 22S1 of the multilayer wiring layer 22). The multiple pad electrodes 227 are electrically connected to some of the wiring in the wiring layer 225 via vias V3.

[0035] The interlayer insulating layer 117, like the interlayer insulating layer 182, is made of, for example, silicon oxide (SiO2). x ), TEOS, silicon nitride (SiN x ) and silicon oxynitride (SiO x N y It is composed of a single layer film made of one of the following, or a laminated film made of two or more of these.

[0036] The gate wiring 221 and wiring layers 222, 223, 224, and 225 are formed using materials such as aluminum (Al), copper (Cu), or tungsten (W), similar to the wiring layer 181.

[0037] The pad electrode 227 is exposed on the bonding surface with the sensor substrate 10 (the 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 using, for example, copper (Cu), similar to the pad electrode 183.

[0038] In the photodetector 1, a CuCu junction, for example, is formed between the pad electrode 183 and the pad electrode 227. As a result, the cathode of the photodetector 12 is electrically connected to the quenching resistor element 120 provided on the logic board 20 side, and the anode of the photodetector 12 is electrically connected to the bias voltage application unit 110.

[0039] On the light incident surface (second surface 11S2) side of the semiconductor substrate 11, for example, microlenses 33 are provided for each unit pixel P via a passivation film 31 and a color filter 32.

[0040] The microlens 33 focuses light incident from above onto the photoreceiving element 12, and is made of, for example, silicon oxide (SiO x It is formed using ) etc.

[0041] (1-2. Method for manufacturing a photodetector) The sensor substrate 10 can be manufactured, for example, as follows: First, the semiconductor substrate 11 is implanted with p-type or n-type impurity concentrations to control the concentration of p-type or n-type impurities, resulting in p-wells (p) 111, n-type semiconductor regions (n) 112, and p-type semiconductor regions (p + Next, a layer 14X is formed on the first surface 11S1 of the semiconductor substrate 11, for example, silicon oxide (SiO x ) or an oxide film such as (SiN xAfter patterning with a nitride film such as ) as a hard mask, through holes are formed by etching, for example, penetrating the semiconductor substrate 11. Subsequently, insulating films 17B, 17C and a light-shielding film 17A are sequentially deposited in the through holes by methods such as CVD (Chemical Vapor Deposition), PVD (Physical Vapor Deposition), ALD (Atomic Layer Deposition), or vapor deposition.

[0042] Next, a semiconductor layer 15 made of, for example, silicon (Si) is formed on the first surface 11S1 of the semiconductor substrate 11 by an epitaxial crystal growth method such as metal-organic chemical vapor deposition (MOCVD). Subsequently, the surface of the semiconductor layer 15 is planarized by, for example, chemical mechanical polishing (CMP), and then n-type semiconductor regions (n) are formed in the semiconductor layer 15 by ion implantation. + )14Y and contact electrode 16(n-type semiconductor region (n ++ This forms an n-type semiconductor region (n + )14Y can be formed with a film thickness of, for example, 1 μm or less.

[0043] Next, the first surface 15S1 of the semiconductor layer 15 is polished, for example by CMP, and then a multilayer wiring layer 18 is formed on the first surface 15S1 of the semiconductor layer 15. After that, a separately prepared logic board 20 is bonded to it. At this time, a plurality of pad electrodes 183 exposed on the bonding surface (surface 18S1) of the multilayer wiring layer 18 and a plurality of pad portions 217 exposed on the bonding surface (surface 22S) of the multilayer wiring layer 22 on the logic board 20 are bonded together using CuCu bonding.

[0044] Next, the second surface 11S2 of the semiconductor substrate 11 is polished, for example by CMP, and then the light-shielding portion 17X, passivation film 31, color filter 32, and microlens 33 are formed in sequence. This completes the photodetector 1 shown in Figure 1.

[0045] (1-3. Action / Effect) In this embodiment, the photodetector 1 has a semiconductor layer 15 on the first surface 1S1 of the semiconductor substrate 11, and within this semiconductor layer 15, an n-type semiconductor region (n + )14Y is provided. This provides an anode that is electrically connected to the light receiving unit 13 and an n-type semiconductor region (n + Ensure sufficient spacing between 14Y and the cathode. This will be explained below.

[0046] In photodetectors with the general SPAD structure described above, it is necessary to increase the lateral distance between the anode and the n-type semiconductor region of the avalanche photodiode (APD) in order to suppress edge breakdown. For this reason, it has been unsuitable for miniaturization.

[0047] One possible solution to this problem is an embedded structure in which the anode is embedded within the silicon substrate. However, this structure requires contact ion implantation after forming an opening for the anode in the silicon substrate, which complicates the manufacturing process.

[0048] In contrast, in this embodiment, a semiconductor layer 15 is provided on the first surface 1S1 of the semiconductor substrate 11, for example, using an epitaxial crystal growth method, and an n-type semiconductor region (n) constituting the multiplication portion 14 is provided within this semiconductor layer 15. + )14Y is provided by ion implantation. This allows the n-type semiconductor region (n + Compared to the case of forming 14Y, the diffusion of impurities is suppressed, making it possible to form a steep charge.

[0049] As described above, the photodetector 1 of this embodiment has an anode that is easily electrically connected to the light receiving section 13 compared to the embedded structure described above, and an n-type semiconductor region (n + This allows for sufficient spacing between the 14Y and cathode, suppressing unintended edge breakdown.

[0050] Furthermore, in the photodetector 1 of this embodiment, the n-type semiconductor region (n + Since 14Y is provided within the semiconductor layer 15, the n-type semiconductor region (n + The light-receiving area (light-receiving section 13) can be expanded by 14Y. Therefore, it becomes possible to improve sensitivity.

[0051] Next, modifications 1 to 11 of the present disclosure, as well as examples of application and application, will be described. In the following, components similar to those in the above embodiments will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0052] <2. Variant> (2-1. Variation 1) Figure 4 schematically shows an example of the cross-sectional configuration of a photodetector (photodetector 1A) according to Modification 1 of the present disclosure. The photodetector 1A is applied to a distance image sensor (distance image device 1000) or image sensor that measures distance by the ToF method, for example, similar to the embodiment described above. In this modified example, the photodetector 1A has a p-type semiconductor region (p + )14X and n-type semiconductor region (n + The difference from the above embodiment is that both ) and 14Y are provided within the semiconductor layer 15.

[0053] Thus, in the modified photodetector 1A, the p-type semiconductor region (p + )14X and n-type semiconductor region (n + Both )14Y are formed within the semiconductor layer 15. This provides, in addition to the effects of the above embodiment, a p-type semiconductor region (p + The 14X magnification allows for a further expansion of the light-receiving area (light-receiving section 13). Therefore, it becomes possible to further improve sensitivity.

[0054] (2-2. Variation 2) Figure 5 schematically shows an example of the cross-sectional configuration of a photodetector (photodetector 1B) according to Modification 2 of the present disclosure. The photodetector 1B is applied to a distance image sensor (distance image device 1000) or image sensor that measures distance by the ToF method, for example, as in the above embodiment. The photodetector 1B of this modified example differs from the above embodiment in that a semiconductor layer 15 is partially provided on the first surface 11S1 of the semiconductor substrate 11 for each unit pixel P.

[0055] Figures 6A to 6C schematically represent an example of the planar shape of the semiconductor layer 15. The semiconductor layer 15 may be rectangular, as shown in Figure 6A, similar to the unit pixel P, or it may be a polygonal shape other than a rectangle, as shown in Figure 6B. Alternatively, it may be circular, as shown in Figure 6C. In particular, when the pixel size is small, the circular shape shown in Figure 6C is preferable from the viewpoint of edge electric field relaxation in the lateral direction (for example, the XY plane direction).

[0056] Such a semiconductor layer 15 can be manufactured as follows. For example, in the same manner as in the above embodiment, a p-well (p) 111, an n-type semiconductor region (n) 112 and a p-type semiconductor region (p + )14X is formed. Next, an insulating layer 19 having openings at predetermined positions is patterned on the first surface 11S1 of the semiconductor substrate 11. The insulating layer 19 is made of, for example, silicon oxide (SiO x ) and silicon nitride (SiN x It can be formed using ). Subsequently, a semiconductor layer 15 is formed in the opening by epitaxial crystal growth.

[0057] Furthermore, in the case where the semiconductor layer 15 is partially provided for each unit pixel P, as in this modified example, the semiconductor substrate 11 can be processed to form a convex structure, and this convex structure portion can be used as the semiconductor layer 15.

[0058] Thus, in the modified photodetector 1B, the semiconductor layer 15 is embedded within the insulating layer 19 for each unit pixel P, and within the semiconductor layer 15, an n-type semiconductor region (n) constituting the multiplication section 14 is formed. +)14Y is provided. As a result, compared to the above embodiment, the anode and the n-type semiconductor region (n + This allows for more reliable spacing from 14Y. Therefore, in addition to the effects of the above embodiment, it becomes possible to further suppress unintended edge breakdown.

[0059] (2-3. Variation 3) Figure 7 schematically shows an example of the cross-sectional configuration of a photodetector (photodetector 1C) according to Modification 3 of this disclosure. The photodetector 1C is applied to a distance image sensor (distance image device 1000) or image sensor that measures distance by the ToF method, for example, similar to the above embodiment. The photodetector 1C of this modification combines Modification 1 and Modification 2, and partially provides a semiconductor layer 15 on the first surface 11S1 of the semiconductor substrate 11 for each unit pixel P, and also provides a p-type semiconductor region (p) that constitutes the multiplication section 14. + )14X and n-type semiconductor region (n + Both ) and 14Y are provided within the semiconductor layer 15.

[0060] Thus, the semiconductor layer 15 is partially provided for each unit pixel P, and within the semiconductor layer 15, a p-type semiconductor region (p) constituting the multiplication section 14 is provided. + )14X and n-type semiconductor region (n + )14Y may also be provided. This allows for the provision of both the anode and the n-type semiconductor region (n) constituting the multiplication section 14. + )This allows for a more reliable spacing with 14Y, and also ensures the p-type semiconductor region (p + The 14X magnification allows for a further expansion of the light-receiving area (light-receiving section 13). This further suppresses unintended edge breakdown and improves sensitivity.

[0061] (2-4. Modification 4) Figure 8 schematically shows an example of the cross-sectional configuration of a photodetector (photodetector 1D) according to Modification 4 of the present disclosure. The photodetector 1D is applied to a distance image sensor (distance image device 1000) or image sensor that measures distance by the ToF method, for example, as in the above embodiment. The photodetector 1D in this modified example differs from the above embodiment in that the pixel separation portion 17 extends further into the semiconductor layer 15, and the pixel separation portion 17 penetrates the semiconductor layer 15.

[0062] Furthermore, in this modified example, the p-type semiconductor region (p + The )113 extends into the semiconductor layer 15 together with the pixel separation portion 17, and is extended toward the inside of the unit pixel P near the first surface 15S1 of the semiconductor layer 15 (extension portion 113X).

[0063] Thus, in this modified optical detection device 1D, the pixel separation unit 17 extends from the semiconductor substrate 11 into the semiconductor layer 15, and the semiconductor layer 15 is separated by the pixel separation unit 17 for each unit pixel P. This makes it possible to suppress crosstalk caused by light emission during avalanche multiplication in the multiplication unit 14. Therefore, in addition to the effects of the above embodiment, it is possible to improve the device characteristics.

[0064] (2-5. Modification 5) Figure 9 schematically shows an example of the cross-sectional configuration of a photodetector (photodetector 1E) according to Modification 5 of this disclosure. The photodetector 1E is applied to a distance image sensor (distance image device 1000) or image sensor that measures distance by the ToF method, for example, as in the above embodiment. The photodetector 1E of this modification differs from the above embodiment in that, in a configuration that combines Modification 1 and Modification 2 above, the side surface of the semiconductor layer 15 partially provided for each unit pixel P is inclined.

[0065] Thus, the angle of the side surface of the semiconductor layer 15, which is partially provided for each unit pixel P, is not particularly limited and may be perpendicular to the first surface 11S1 of the semiconductor substrate 11, or it may be inclined.

[0066] (2-6. Variation 6) Figure 10 schematically shows an example of the cross-sectional configuration of a photodetector (photodetector 1F) according to Modification 6 of this disclosure. The photodetector 1F is applied to a distance image sensor (distance image device 1000) or image sensor that measures distance by the ToF method, for example, as in the above embodiment. The photodetector 1F of this modification is a further modification of Modification 2 above, and has an n-type semiconductor region (n + The difference from the above embodiment is that the end face of 14Y is formed inward from the side surface of the semiconductor layer 15.

[0067] Thus, in the modified photodetector 1F, the n-type semiconductor region (n + The end face of 14Y is formed inward from the side surface of the semiconductor layer 15 provided for each unit pixel P, and an n-type semiconductor region (n + An unformed region of 14Y was provided. This makes it possible to reduce the avalanche multiplication of dark current generated at the interface on the side surface of the semiconductor layer 15.

[0068] (2-7. Variation 7) Figure 11 schematically shows an example of the cross-sectional configuration of a photodetector (photodetector 1G) according to Modification 7 of this disclosure. The photodetector 1G is applied to a distance image sensor (distance image device 1000) or image sensor that measures distance by the ToF method, for example, similar to the above embodiment. The photodetector 1G of this modification is a combination of Modification 1 and Modification 6, and the p-type semiconductor region (p + )14X and n-type semiconductor region (n + Both end faces of 14Y are formed inward from the side surfaces of the semiconductor layer 15, which is partially provided for each unit pixel P.

[0069] This makes it possible to further expand the light-receiving area (light-receiving section 13) while reducing the avalanche multiplication of dark current generated at the interface on the side surface of the semiconductor layer 15.

[0070] (2-8. Variation 8) Figure 12 schematically shows an example of the cross-sectional configuration of a photodetector (photodetector 1H) according to Modification 8 of the present disclosure. Figure 13 shows the p-type semiconductor region (p) in the unit pixel P of the photodetector 1H shown in Figure 12. + )14X and n-type semiconductor region (n + This schematically represents the planar layout of 14Y. The photodetector 1H is applied to a distance image sensor (distance image device 1000) or image sensor that measures distance by the ToF method, for example, as in the above embodiment. In this modified example, the photodetector 1H has an n-type semiconductor region (n + This modification differs from the above modification 2 in that multiple semiconductor layers 15 on which 14Y is formed are provided for each unit pixel P.

[0071] Thus, the n-type semiconductor region (n + Multiple semiconductor layers 15 on which 14Y is formed may be provided in a unit pixel P. This makes it possible to improve the light absorption efficiency in addition to the effects of the above embodiment.

[0072] (2-9. Variation 9) Figure 14 schematically shows an example of the cross-sectional configuration of a photodetector (photodetector 1I) according to Modification 9 of this disclosure. Figure 15 schematically shows an example of the planar layout of the reflective layer 41 in a unit pixel P of the photodetector 1I shown in Figure 14. The photodetector 1I is applied to a distance image sensor (distance image device 1000) or an image sensor that measures distance by the ToF method, for example, similar to the embodiment described above. In addition to the configuration of Modification 2 described above, the photodetector 1I of this modification is provided with a reflective layer 41 surrounding the semiconductor layer 15 within an insulating layer 19 provided around the semiconductor layer 15.

[0073] The reflective layer 41 can be formed using, for example, a wiring material having light reflectivity such as aluminum (Al).

[0074] Thus, in this modified photodetector 1I, a reflective layer 41 is provided within the insulating layer 19 surrounding the semiconductor layer 15, for example, surrounding the semiconductor layer 15. As a result, light that is transmitted without being absorbed by the light-receiving unit 13 is reflected by the reflective layer 41 and re-incidentated to the light-receiving unit 13. Therefore, in addition to the effects of the modified example 2 described above, it is possible to further improve the sensitivity.

[0075] (2-10. Variation 10) Figure 16 schematically shows an example of a cross-sectional configuration of a photodetector (photodetector 1J) according to Modification 10 of the present disclosure. Figure 17 schematically shows an example of a wiring layout for the reflective layer 41 shown in Figure 16. The photodetector 1J is applied to a distance image sensor (distance image device 1000) or image sensor that measures distance by the ToF method, for example, similar to the embodiment described above. The reflective layer 41 may be partially divided, with one end electrically connected to the cathode (contact electrode 16) via a via V1, for example, and the other end electrically connected to the readout circuit. This allows the reflective layer 41 to be used as a resistive element in the readout circuit. Therefore, it is possible to improve the area efficiency of the readout circuit.

[0076] (2-11. Variation 11) Figure 18 schematically shows an example of a cross-sectional configuration of a photodetector (photodetector 1K) according to Modification 11 of this disclosure. The photodetector 1K is applied to a distance image sensor (distance image device 1000) or an image sensor that measures distance by the ToF method, for example, similar to the above embodiment. In Modification 9 above, a reflective layer 41 is provided in an insulating layer 19 provided around the semiconductor layer 15, so that light that is transmitted without being absorbed by the light receiving unit 13 is re-incidentated to the light receiving unit 13. In contrast, in this modification, a portion of the wiring (for example, wiring 181A) of the wiring layer 181 provided in the interlayer insulating layer 182 is extended in the XY plane direction and used as a reflective layer. As a result, similar to Modification 0 above, light that is transmitted without being absorbed by the light receiving unit 13 can be re-incidentated to the light receiving unit 13.

[0077] <3. Application Examples> Figure 19 shows an example of a schematic configuration of a distance imaging device 1000 as an electronic device equipped with a light detection device (for example, light detection device 1) according to the above embodiment and modifications 1 to 11. This distance imaging device 1000 corresponds to one specific example of the "distance measuring device" of this disclosure.

[0078] The distance imaging device 1000 includes, for example, a light source device 1100, an optical system 1200, a light detection device 1, an image processing circuit 1300, a monitor 1400, and a memory 1500.

[0079] The distance imaging device 1000 emits light from the light source device 1100 toward the object 2000 to be illuminated, and by receiving the light (modulated light or pulsed light) reflected from the surface of the object 2000, it can acquire a distance image corresponding to the distance to the object 2000.

[0080] The optical system 1200 is composed of one or more lenses and guides the image light (incident light) from the object to be illuminated 2000 to the light detection device 1, and forms an image on the light-receiving surface (sensor part) of the light detection device 1.

[0081] The image processing circuit 1300 performs image processing to construct a distance image based on the distance signal supplied from the light detection device 1. The distance image (image data) obtained through this image processing is supplied to the monitor 1400 for display or supplied to the memory 1500 for storage (recording).

[0082] In the distance imaging device 1000 configured in this way, by applying the above-described light detection device (for example, light detection device 1), it becomes possible to calculate the distance to the illuminated object 2000 based only on the light received signal from the highly stable unit pixel P, and to generate a highly accurate distance image. In other words, the distance imaging device 1000 can acquire a more accurate distance image.

[0083] <4. Application Examples> (Examples of applications to mobile devices) The technology disclosed herein can be applied to a variety of products. For example, the technology disclosed herein may be implemented as a device mounted on any type of mobile vehicle, such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, robots, construction machinery, or agricultural machinery (tractors).

[0084] Figure 20 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0085] The vehicle control system 12000 comprises multiple electronic control units connected via a communication network 12001. In the example shown in Figure 20, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is also shown, consisting of a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0086] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0087] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0088] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0089] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0090] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that images the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0091] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking system based on information from inside and outside the vehicle acquired by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0092] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0093] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0094] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 20, the output devices are exemplified as an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

[0095] Figure 21 shows an example of the installation position of the imaging unit 12031.

[0096] In Figure 21, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0097] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0098] Figure 21 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0099] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0100] For example, the microcomputer 12051, based on distance information obtained from imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to vehicle 12100). In particular, it can extract the nearest object on the vehicle 12100's path that is traveling in approximately the same direction as vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0101] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, heavy vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid collisions by outputting a warning to the driver via the audio speaker 12061 or display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0102] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio-image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio-image output unit 12052 may also control the display unit 12062 to display an icon indicating a pedestrian at a desired position.

[0103] Although embodiments and modifications 1 to 11, as well as application examples and usage examples, have been described above, the contents of this disclosure are not limited to the above embodiments, and various modifications are possible. For example, the photodetector in this disclosure does not need to have all of the components described in the above embodiments, and conversely, it may have other layers. For example, if the photodetector 1 detects light other than visible light (for example, near-infrared light (IR)), the color filter 32 may be omitted.

[0104] Furthermore, the polarity of the semiconductor region constituting the photodetector device of this disclosure may be reversed. Moreover, the photodetector device of this disclosure may use holes as signal charges.

[0105] Furthermore, the photodetector device of this disclosure is not limited in terms of the potentials of the anode and cathode, provided that avalanche multiplication occurs when a reverse bias is applied between them.

[0106] Furthermore, although the above embodiments show examples in which silicon is used as the semiconductor substrate 11 and semiconductor layer 15, the semiconductor substrate 11 and semiconductor layer 15 can also be, for example, germanium (Ge) or a compound semiconductor of silicon (Si) and germanium (Ge) (for example, silicon germanium (SiGe)).

[0107] The effects described in the above embodiments are merely examples, and other effects may also be present, or even further effects may be included.

[0108] Furthermore, this disclosure may also have the following configuration. According to the technology with the following configuration, a semiconductor layer is provided on the first surface side of a semiconductor substrate having opposing first and second surfaces, and at least the second conductivity type region of the first and second conductivity type regions constituting the multiplication portion is provided within the semiconductor layer. As a result, a gap is secured between the first electrode electrically connected to the light receiving portion and the second conductivity type region constituting the multiplication portion, making it possible to suppress unintended edge breakdown. (1) A semiconductor substrate having a first surface and a second surface facing each other, and a pixel array portion in which a plurality of pixels are arranged in an array, A semiconductor layer provided on the first surface side of the semiconductor substrate, Each of the aforementioned pixels is provided inside the semiconductor substrate and includes a light-receiving unit that generates carriers by photoelectric conversion according to the amount of light received, The semiconductor layer has a first conductive type region and a second conductive type region stacked sequentially on the first surface side, with at least the second conductive type region provided in the semiconductor layer, and a multiplier that avalanches the carriers generated in the light receiving section, A first electrode provided on the first surface side and electrically connected to the light receiving portion, A second electrode is provided on the first surface side and is electrically connected to the multiplier. Equipped with 、 The semiconductor substrate further has an insulating layer on the first surface side, The semiconductor layer is embedded in the insulating layer for each pixel, The insulating layer is provided within the insulating layer and further comprises a reflective layer surrounding the semiconductor layer. Light detection device. (2) The photodetector according to (1), wherein both the first conductivity type region and the second conductivity type region are provided in the semiconductor layer. (3) The multiplication portion formed within the semiconductor layer has an end face that is inward from the side surface of the semiconductor layer. (1) or (2) above The light detection device described above. (4) The side surface of the semiconductor layer is inclined with respect to the first surface. The above (1) to (3) A light detection device as described in any one of the following. (5) The semiconductor substrate further comprises a pixel separation portion that divides each of the plurality of pixels and penetrates between the first surface and the second surface. The above (1) to (4) A light detection device as described in any one of the following. (6) The aforementioned pixel separation portion further penetrates the semiconductor layer, (5) above The light detection device described above. (7) The pixel separation portion is composed of a light-shielding conductive film and an insulating film provided between the conductive film and the semiconductor substrate. (5) or (6) above The light detection device described above. (8) The pixel separation portion further has an impurity region of the first conductivity type, The light-receiving portion and the first electrode are electrically connected via the impurity region of the first conductivity type. The above (5) to (7) A light detection device as described in any one of the following. (9) The reflective layer is divided, one end of which is connected to the second electrode, and the other end of which is connected to a readout circuit that reads out the carriers amplified in the multiplication unit. Any one of the above (1) through (8) The light detection device described above. (10) The semiconductor substrate and the semiconductor layer are formed containing silicon. The above (1) to (9) A light detection device as described in any one of the following. (11) The system comprises an optical system, a light detection device, and a signal processing circuit that calculates the distance to the object to be measured from the output signal of the light detection device. The aforementioned light detection device is A semiconductor substrate having a first surface and a second surface facing each other, and a pixel array portion in which a plurality of pixels are arranged in an array, A semiconductor layer provided on the first surface side of the semiconductor substrate, Each of the aforementioned pixels is provided inside the semiconductor substrate and includes a light-receiving unit that generates carriers by photoelectric conversion according to the amount of light received, The semiconductor layer has a first conductive type region and a second conductive type region stacked sequentially on the first surface side, with at least the second conductive type region provided in the semiconductor layer, and a multiplier that avalanches the carriers generated in the light receiving section, A first electrode provided on the first surface side and electrically connected to the light receiving portion, A second electrode is provided on the first surface side and is electrically connected to the multiplier. to have death, The semiconductor substrate further has an insulating layer on the first surface side, The semiconductor layer is embedded in the insulating layer for each pixel, The insulating layer is provided within the insulating layer and further comprises a reflective layer surrounding the semiconductor layer. Ranging device.

[0109] This application claims priority based on Japanese Patent Application No. 2021-011535, filed with the Japan Patent Office on 27 January 2021, and all contents of that application are incorporated herein by reference.

[0110] Those skilled in the art will understand that various modifications, combinations, subcombinations, and changes can be conceived depending on design requirements and other factors, and that these fall within the scope of the attached claims and their equivalents.

Claims

1. A semiconductor substrate having a first surface and a second surface facing each other, and a pixel array portion in which a plurality of pixels are arranged in an array, A semiconductor layer provided on the first surface side of the semiconductor substrate, Each of the aforementioned pixels is provided inside the semiconductor substrate and includes a light-receiving unit that generates carriers by photoelectric conversion according to the amount of light received, The semiconductor layer has a first conductive type region and a second conductive type region sequentially stacked on the first surface side, with at least the second conductive type region provided in the semiconductor layer, and a multiplier that avalanches the carriers generated in the light receiving section, A first electrode provided on the first surface side and electrically connected to the light receiving portion, A second electrode provided on the first surface side and electrically connected to the multiplier portion and Equipped with, The semiconductor substrate further has an insulating layer on the first surface side, The semiconductor layer is embedded in the insulating layer for each pixel, The insulating layer is provided within the insulating layer and further comprises a reflective layer surrounding the semiconductor layer. Light detection device.

2. The photodetector according to claim 1, wherein both the first conductivity type region and the second conductivity type region are provided in the semiconductor layer in the amplification section.

3. The photodetector according to claim 1, wherein the multiplier formed in the semiconductor layer has an end face that is inward from the side surface of the semiconductor layer.

4. The photodetector according to claim 1, wherein the side surface of the semiconductor layer is inclined with respect to the first surface.

5. The photodetector according to claim 1, wherein the semiconductor substrate further comprises a pixel separation portion that partitions each of the plurality of pixels and penetrates between the first surface and the second surface.

6. The photodetector according to claim 5, wherein the pixel separation portion further penetrates the semiconductor layer.

7. The photodetector according to claim 5, wherein the pixel separation portion is composed of a light-shielding conductive film and an insulating film provided between the conductive film and the semiconductor substrate.

8. The pixel separation portion further has an impurity region of a first conductivity type, The photodetector according to claim 5, wherein the light-receiving unit and the first electrode are electrically connected via the impurity region of the first conductivity type.

9. The photodetector according to claim 1, wherein the reflective layer is divided, one end of which is connected to the second electrode, and the other end of which is connected to a readout circuit that reads out the carriers amplified in the multiplication unit.

10. The photodetector according to claim 1, wherein the semiconductor substrate and the semiconductor layer are formed by including silicon.

11. The system comprises an optical system, a light detection device, and a signal processing circuit that calculates the distance to the object to be measured from the output signal of the light detection device. The aforementioned light detection device is A semiconductor substrate having a first surface and a second surface facing each other, and a pixel array portion in which a plurality of pixels are arranged in an array, A semiconductor layer provided on the first surface side of the semiconductor substrate, Each of the aforementioned pixels is provided inside the semiconductor substrate and includes a light-receiving unit that generates carriers by photoelectric conversion according to the amount of light received, The semiconductor layer has a first conductive type region and a second conductive type region sequentially stacked on the first surface side, with at least the second conductive type region provided in the semiconductor layer, and a multiplier that avalanches the carriers generated in the light receiving section, A first electrode provided on the first surface side and electrically connected to the light receiving portion, A second electrode provided on the first surface side and electrically connected to the multiplier portion and It has, The semiconductor substrate further has an insulating layer on the first surface side, The semiconductor layer is embedded in the insulating layer for each pixel, The insulating layer is provided within the insulating layer and further comprises a reflective layer surrounding the semiconductor layer. Ranging device.

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