Photoelectric conversion device, photoelectric conversion system, and movable object

Abstract

The present application relates to a photoelectric conversion device, a photoelectric conversion system, and a movable object. A first avalanche diode including a first semiconductor region of a first conductivity type and a second avalanche diode including a second semiconductor region of the first conductivity type are provided. A first isolation portion is arranged between the first semiconductor region and the second semiconductor region. The first isolation portion is constituted by a third semiconductor region of the first conductivity type, or a fourth semiconductor region of a second conductivity type and the third semiconductor region arranged to sandwich the fourth semiconductor region in a plan view. The third semiconductor region satisfies Expression 1, where Nd is an impurity concentration of the third semiconductor region, Na is an impurity concentration of the fourth semiconductor region, q is an elementary electric charge, ε is a dielectric constant of a semiconductor, V is a potential difference between a P-N junction of the third semiconductor region and the fourth semiconductor region, and D is a length of the fourth semiconductor region sandwiched by the third semiconductor region,

Description

TECHNICAL FIELD

[0001] The present application relates to a photoelectric conversion device, a photoelectric conversion system, and a movable object. BACKGROUND

[0002] A photoelectric conversion device is known which digitally counts the number of photons reaching a light-receiving portion and outputs the count value as a digital signal from a pixel. Patent Literature 1 discloses a light detection device using an avalanche diode which causes avalanche multiplication in a P-N junction region of a semiconductor region constituting a photoelectric conversion portion. In the light detection device of Patent Literature 1, a high-concentration P-type semiconductor region for forming an electrical contact is arranged between N-type semiconductor regions of avalanche diodes adjacent to each other.

[0003] LIST OF CITATIONS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2018-201005 SUMMARY

[0006] PROBLEMS

[0007] According to Patent Literature 1, when the pixel size is reduced, the distance between the P-type semiconductor region and the N-type semiconductor region constituting the avalanche diode is reduced. When a potential is supplied to the avalanche diode in this state, a local high electric field region is formed by the N-type semiconductor region and the high-concentration P-type semiconductor region for forming an electrical contact, and it is likely that a dark current is generated.

[0008] TECHNICAL SOLUTION TO THE PROBLEM

[0009] A photoelectric conversion device according to an aspect of the present application includes a first avalanche diode including a first semiconductor region of a first conductivity type in which a majority carrier is a charge carrier of the same conductivity type as a signal charge, and a second avalanche diode including a second semiconductor region of the first conductivity type and arranged adjacent to the first avalanche diode, wherein a first isolation portion is arranged between the first semiconductor region and the second semiconductor region, the first isolation portion is constituted by a third semiconductor region of the first conductivity type, or a fourth semiconductor region of a second conductivity type and the third semiconductor region, and in the third semiconductor region, an impurity concentration Nd of the third semiconductor region, an impurity concentration Na of the fourth semiconductor region, a elementary charge q, a dielectric constant ε of a semiconductor, a potential difference V between a P-N junction of the third semiconductor region and the fourth semiconductor region, and a length D of the fourth semiconductor region sandwiched by the third semiconductor region satisfy the following expression.

[0010] [Expression 1]

[0011]

[0012] A photoelectric conversion device according to an aspect of the present application includes: a substrate having a first surface and a second surface opposite to the first surface; a first avalanche diode including a first semiconductor region of a first conductivity type arranged at a first depth of the substrate, a majority of charge carriers of which is of the same conductivity type as a signal charge, and a fifth semiconductor region of a second conductivity type arranged at a second depth between the first depth and the second surface, the second conductivity type being a different conductivity type from the first conductivity type; and a second avalanche diode including a second semiconductor region of the first conductivity type arranged at the first depth of the substrate, and a sixth semiconductor region of the second conductivity type arranged at the second depth, the second avalanche diode being arranged adjacent to the first avalanche diode, wherein a first isolation portion is arranged at the first depth between the first semiconductor region and the second semiconductor region, at least one of an intrinsic semiconductor region, a third semiconductor region of the first conductivity type, and a fourth semiconductor region of the second conductivity type is arranged in the first isolation portion, a seventh semiconductor region of the second conductivity type is arranged at the second depth between the fifth semiconductor region and the sixth semiconductor region, and on a line passing through the first isolation portion and the seventh semiconductor region, a potential height with respect to the signal charge decreases from the seventh semiconductor region toward the first isolation portion, and a difference between the potential height with respect to the signal charge in the first semiconductor region and the potential height with respect to the signal charge in the fifth semiconductor region is greater than a difference between the potential height with respect to the signal charge in the first isolation portion and the potential height with respect to the signal charge in the seventh semiconductor region.

[0013] A photoelectric conversion device according to an aspect of the present application includes: a first avalanche diode including a first semiconductor region of a first conductivity type, a majority of charge carriers of which is of the same conductivity type as a signal charge; and a second avalanche diode including a second semiconductor region of the first conductivity type and arranged adjacent to the first avalanche diode, and the photoelectric conversion device includes: a first counter circuit configured to count avalanche current generated by avalanche multiplication in the first avalanche diode; and a second counter circuit different from the first counter circuit and configured to count avalanche current generated by avalanche multiplication in the second avalanche diode, and in a plan view, a contact plug that applies a bias to one node of the first avalanche diode is not arranged between the first semiconductor region and the second semiconductor region.

[0014] Advantages of the present invention

[0015] According to the present invention, in a photoelectric conversion device using an avalanche diode, it is possible to reduce the pixel size while suppressing an increase in dark current. BRIEF DESCRIPTION OF DRAWINGS

[0016] [ FIG. 1 ] FIG. 1 is a block diagram of a photoelectric conversion device.

[0017] [ FIG. 2 ] FIG. 2 is a block diagram of a pixel.

[0018] [ FIG. 3 ] FIG. 3 is a partially enlarged plan view of a photoelectric conversion device of a first embodiment.

[0019] [ FIG. 4A ] FIG. 4A is a cross-sectional view of a photoelectric conversion device of the first embodiment.

[0020] [ FIG. 4B ] FIG. 4B is a cross-sectional view of a photoelectric conversion device of the first embodiment.

[0021] [ FIG. 5A ] FIG. 5A is a potential diagram of a photoelectric conversion device of the first embodiment.

[0022] [ FIG. 5B ] FIG. 5B is a potential diagram of a photoelectric conversion device of the first embodiment.

[0023] [ FIG. 5C ] FIG. 5C is a potential diagram of a photoelectric conversion device of the first embodiment.

[0024] [ FIG. 6A ] FIG. 6A is a cross-sectional view of a photoelectric conversion device of a comparative example.

[0025] [ FIG. 6B ] FIG. 6B is a potential diagram of a photoelectric conversion device of the comparative example.

[0026] [ FIG. 7 ] FIG. 7 is a partially enlarged plan view of a photoelectric conversion device of a second embodiment.

[0027] [ FIG. 8 ] FIG. 8 is a cross-sectional view of a photoelectric conversion device of the second embodiment.

[0028] [ FIG. 9 ] FIG. 9is a partially enlarged plan view of the photoelectric conversion device of the third embodiment.

[0029] [ FIG. 10 ] FIG. 10 is a cross-sectional view of the photoelectric conversion device of the third embodiment.

[0030] [ FIG. 11 ] FIG. 11 is a modification of the third embodiment.

[0031] [ FIG. 12 ] FIG. 12 is a partially enlarged plan view of the photoelectric conversion device of the fourth embodiment.

[0032] [ FIG. 13 ] FIG. 13 is a cross-sectional view of the photoelectric conversion device of the fourth embodiment.

[0033] [ FIG. 14 ] FIG. 14 is a cross-sectional view of the photoelectric conversion device of the fifth embodiment.

[0034] [ FIG. 15 ] FIG. 15 is a partially enlarged plan view of the photoelectric conversion device of the sixth embodiment.

[0035] [ FIG. 16 ] FIG. 16 is a cross-sectional view of the photoelectric conversion device of the sixth embodiment.

[0036] [ FIG. 17 ] FIG. 17 is a partially enlarged plan view of the photoelectric conversion device of the seventh embodiment.

[0037] [ FIG. 18 ] FIG. 18 is a cross-sectional view of the photoelectric conversion device of the seventh embodiment.

[0038] [ FIG. 19 ] FIG. 19 is a cross-sectional view of the photoelectric conversion device of the eighth embodiment.

[0039] [ FIG. 20 ] FIG. 20 is a cross-sectional view of the photoelectric conversion device of the ninth embodiment.

[0040] [ FIG. 21 ] FIG. 21 is a photoelectric conversion system according to the tenth embodiment.

[0041] [ FIG. 22 ] FIG. 22 is a photoelectric conversion system according to the eleventh embodiment.

[0042] [ FIG. 23A ]FIG. 23A is a schematic diagram of a photoelectric conversion system and a movable object of the twelfth embodiment.

[0043] [ FIG. 23B ] FIG. 23B is a schematic diagram of a photoelectric conversion system and a movable object of the twelfth embodiment.

[0044] [ FIG. 24 ] FIG. 24 is a flowchart showing the operation of the photoelectric conversion system of the twelfth embodiment.

[0045] [ FIG. 25 ] FIG. 25 is a photoelectric conversion system according to the thirteenth embodiment.

[0046] [ FIG. 26 ] FIG. 26 is a photoelectric conversion system according to the fourteenth embodiment.

[0047] [ FIG. 27 ] FIG. 27 is a block diagram of a photoelectric conversion system according to the fourteenth embodiment.

[0048] [ FIG. 28A ] FIG. 28A is a photoelectric conversion system according to the fifteenth embodiment.

[0049] [ FIG. 28B ] FIG. 28B is a photoelectric conversion system according to the fifteenth embodiment.

[0050] [ FIG. 28C ] FIG. 28C is a photoelectric conversion system according to the fifteenth embodiment.

[0051] [ FIG. 29 ] FIG. 29 is a photoelectric conversion system according to the fifteenth embodiment.

[0052] [ FIG. 30A ] FIG. 30A is an experimental example of a photoelectric conversion system according to the fifteenth embodiment.

[0053] [ FIG. 30B ] FIG. 30B is an experimental example of a photoelectric conversion system according to the fifteenth embodiment.

[0054] [ FIG. 30C ] FIG. 30C is an experimental example of a photoelectric conversion system according to the fifteenth embodiment.

[0055] [ FIG. 31A ] FIG. 31A is a photoelectric conversion device according to the sixteenth embodiment.

[0056] [ FIG. 31B ] FIG. 31B is a photoelectric conversion device according to a sixteenth embodiment.

[0057] [ FIG. 32 ] FIG. 32 is a spectral transmittance of a filter according to a seventeenth embodiment.

[0058] [ FIG. 33A ] FIG. 33A is an arrangement example of a pixel and a filter according to the seventeenth embodiment.

[0059] [ FIG. 33B ] FIG. 33B is an arrangement example of a pixel and a filter according to the seventeenth embodiment.

[0060] [ FIG. 34 ] FIG. 34 is an arrangement example of a pixel and a filter according to the seventeenth embodiment.

[0061] [ FIG. 35A ] FIG. 35A is an arrangement example of a pixel and a filter according to the seventeenth embodiment.

[0062] [ FIG. 35B ] FIG. 35B is an arrangement example of a pixel and a filter according to the seventeenth embodiment. DETAILED DESCRIPTION

[0063] The following embodiments to be exemplified are for embodying the technical idea of the present application and are not for limiting the present application. The size and positional relationship of the members shown in each drawing can be exaggerated for the convenience of description. In the following description, the same configuration is assigned the same number and its description can be omitted.

[0064] The following embodiments to be exemplified relate to, inter alia, a photoelectric conversion device including a SPAD (Single Photon Avalanche Diode) that counts the number of photons incident on an avalanche diode. The photoelectric conversion device includes at least an avalanche diode.

[0065] In the following description, the anode of the avalanche diode has a fixed potential, and a signal is acquired from the cathode side. Therefore, the semiconductor region of the first conductivity type refers to an N-type semiconductor region, and the semiconductor region of the second conductivity type refers to a P-type semiconductor region, in the semiconductor region of the first conductivity type, the majority carriers are charge carriers of the same conductivity type as the signal charge. Note that the present application holds even in the case where the cathode of the avalanche diode has a fixed potential and a signal is acquired from the anode side. In this case, the semiconductor region of the first conductivity type refers to a P-type semiconductor region, and the semiconductor region of the second conductivity type refers to an N-type semiconductor region, in the semiconductor region of the first conductivity type, the majority carriers are charge carriers of the same conductivity type as the signal charge. The case where a fixed potential is provided at one of the nodes of the avalanche diode but the potentials at both nodes can fluctuate will be described below.

[0066] FIG. 1 is a block diagram of a photoelectric conversion device 1000 of the present embodiment. The photoelectric conversion device 1000 has a pixel region 111, a horizontal scan circuit section 105, signal lines 104, and a vertical scan circuit section 103.

[0067] A plurality of pixels 110 are two-dimensionally arranged in the pixel region 111. One pixel 110 is constituted by a photoelectric conversion section 101 and a pixel signal processing section 102. The photoelectric conversion section 101 converts light into an electric signal. The pixel signal processing section 102 outputs the converted electric signal to the signal line 104.

[0068] The vertical scan circuit section 103 and the horizontal scan circuit section 105 supply control pulses to each pixel 110. A logic circuit such as a shift register or an address decoder is used as the vertical scan circuit section 103.

[0069] Each signal line 104 supplies a digital signal output from the pixel 110 selected by the vertical scan circuit section 103 to a circuit in the rear stage of the pixel 110 as a potential signal.

[0070] In FIG. 1 , the array of the pixels 110 in the pixel region 111 can be one-dimensionally arranged. In addition, the pixel region 111 can be divided into blocks each having a plurality of pixel columns, and the vertical scan circuit section 103 and the horizontal scan circuit section 105 can be arranged for each block. Further, the vertical scan circuit section 103 and the horizontal scan circuit section 105 can be arranged for each pixel column.

[0071] It is not necessary to provide the function of the pixel signal processing section 102 for each pixel 110, and for example, a single pixel signal processing section 102 can be shared by a plurality of pixels 110, and the signal processing can be performed sequentially. In addition, in order to increase the aperture ratio of the photoelectric conversion section 101, at least a part of the pixel signal processing section 102 can be provided on a semiconductor substrate (second substrate) different from the photoelectric conversion section 101. In this case, the photoelectric conversion section 101 and the pixel signal processing section 102 are electrically connected to each other via a connection line provided for each pixel. The avalanche diode of the photoelectric conversion section 101 is preferably arranged on the first substrate, and the other configurations are preferably arranged on the second substrate. The vertical scanning circuit section 103, the horizontal scanning circuit section 105, and the signal line 104 can be provided on the second substrate.

[0072] FIG. 2 is a block diagram of the pixel 110 including an equivalent circuit according to the present embodiment. In FIG. 2 , a single pixel 110 is constituted by a photoelectric conversion section 101 and a pixel signal processing section 102.

[0073] The photoelectric conversion section 101 has one or a plurality of avalanche diodes 201, quenching elements 202, and waveform shaping sections 203 arranged in line.

[0074] The avalanche diode 201 generates a pair of charges by photoelectric conversion according to incident light. A potential based on a higher potential VH than a potential VL supplied to the anode is supplied to the cathode of the avalanche diode 201. Then, a potential having such a reverse bias is supplied to the anode and the cathode of the avalanche diode 201, so that a photon incident on the avalanche diode 201 undergoes avalanche multiplication. When photoelectric conversion is performed in a state where a potential that provides a reverse bias is supplied, avalanche multiplication is caused by a charge generated by incident light to generate an avalanche current.

[0075] In the case where a potential that provides a reverse bias is supplied, when the potential difference between the anode and the cathode is greater than the breakdown voltage, the avalanche diode enters Geiger mode operation. An avalanche diode that uses Geiger mode operation for rapid detection of a weak signal of a single photon level is a SPAD (Single Photon Avalanche Diode).

[0076] The quenching element 202 is connected to the avalanche diode 201 and a power supply that supplies a high potential VH. The quenching element 202 is constituted by a P-type MOS transistor or a resistive element such as a polysilicon resistor. In addition, the quenching element 202 can be constituted by a plurality of MOS transistors connected in series. When the photo current is multiplied by avalanche multiplication in the avalanche diode 201, the current obtained by the multiplied charge flows to a connection node between the avalanche diode 201 and the quenching element 202. Due to the voltage drop caused by this current, the potential at the cathode of the avalanche diode 201 decreases, and the avalanche diode 201 no longer forms an electron avalanche. In this way, the avalanche multiplication of the avalanche diode 201 stops. Thereafter, since the potential VH of the power supply is supplied to the cathode of the avalanche diode 201 via the quenching element 202, the potential supplied to the cathode of the avalanche diode 201 returns to the potential VH. That is, the operation region of the avalanche diode 201 again enters Geiger mode operation. In this way, the quenching element 202 functions as a load circuit (quenching circuit) when the charge multiplied by avalanche multiplication is multiplied, and suppresses the avalanche multiplication (quenching operation). Furthermore, the quenching element causes the operation region of the avalanche diode to again enter the Geiger mode after the avalanche multiplication is suppressed.

[0077] The waveform shaping section 203 is connected to a connection node between the node of the avalanche diode 201 and the node of the quenching element 202. By shaping the potential change at the cathode of the avalanche diode 201 obtained at the time of photon detection, a rectangular pulse signal is output. For example, an inverter circuit is used as the waveform shaping section 203. An example in which a single inverter is used as the waveform shaping section 203 is illustrated, but a circuit obtained by connecting a plurality of inverters in series can also be used. Not only an inverter but also other circuits having a waveform shaping effect can be used.

[0078] The pixel signal processing section 102 has a counter circuit 204 and a selection circuit 205.

[0079] The counter circuit 204 is connected to the waveform shaping section 203. The pulse signal output from the waveform shaping section 203 is counted by the counter circuit 204. In the case where the counter circuit 204 is, for example, an N-bit counter (N: a positive integer), the pulse signal of a single photon can be counted up to approximately 2 raised to the power of N at the maximum. The count signal is held as a detection signal. In addition, when a control pulse Res is supplied via a control line, the signal held in the counter circuit 204 is reset.

[0080] The selection circuit 205 is connected to the counter circuit 204 and the signal line 104. The count signal held in the counter circuit 204 is supplied to the signal line 104 via the selection circuit 205. The selection circuit 205 is controlled by a control signal Sel supplied from the control circuit 101 via a control line. When the control signal Sel is at a high level, the selection circuit 205 outputs the count signal held in the counter circuit 204 to the signal line 104. When the control signal Sel is at a low level, the selection circuit 205 does not output the count signal held in the counter circuit 204 to the signal line 104. FIG. 1The vertical scanning circuit section 103 of the pixel 100 supplies a control pulse Sel to the selection circuit 205 and switches whether or not to output the count value of the counter circuit 204 to the signal line 104. The selection circuit 205 includes, for example, a buffer circuit configured to output a signal, or the like.

[0081] Note that a switch such as a transistor can be arranged between the quenching element 202 and the avalanche diode 201 to switch between a mode in which the avalanche diode 201 is able to perform avalanche multiplication and a mode in which the avalanche diode 201 is not able to perform avalanche multiplication. Similarly, a switch such as a transistor can be used to electrically switch the supply of the potential of the high potential VH or the low potential VL supplied to the avalanche diode 201. In addition, a switch such as a transistor can be arranged between the photoelectric conversion section 101 and the pixel signal processing section 102 to control the signal input from the photoelectric conversion section 101 to the counter circuit 204.

[0082] In the pixel region 111 in which a plurality of pixels 110 are arranged in a matrix shape, a captured image can be obtained by a rolling shutter operation in which the count of the counter circuit 204 is reset for each row in order and the signal held in the counter circuit 204 is output for each row in order.

[0083] Alternatively, a captured image can be obtained by a global electronic shutter operation in which the count of the counter circuit 204 is reset for all pixel rows at the same time and the signal held in the counter circuit 204 is output for each row in order. Note that in the case of performing the global electronic shutter operation, it is preferable to provide a means for switching between a case in which the count of the counter circuit 204 is performed and a case in which the count is not performed. The means for switching refers to, for example, the above-described switch.

[0084] FIG. 2 A configuration using the counter circuit 204 is shown. Instead of the counter circuit 204, a configuration for obtaining the pulse detection timing using a time-to-digital conversion circuit (time-to-digital converter: hereinafter referred to as TDC) or a memory can be employed.

[0085] At this time, the generation timing of the pulse signal output from the waveform shaping section 203 is converted into a digital signal by the TDC. In order to measure the timing of the pulse signal, a control pulse Ref (reference signal) is supplied from FIG. 1 the vertical scanning circuit section 103 of the pixel 100 to the TDC. By using the control pulse pREF as a reference, the TDC obtains a signal when the input timing of the signal output from each pixel via the waveform shaping section 203 is set to a relative time, as a digital signal.

[0086] <First Embodiment>

[0087] A configuration using FIG. 3 to FIG. 5CThe configuration of the photoelectric conversion device according to the first embodiment is described.

[0088] FIG. 3 is a partial enlarged plan view of a pixel region of the photoelectric conversion device according to the first embodiment. FIG. 4A is a schematic cross-sectional view taken along FIG. 3 A-A' in FIG. 4B is a schematic cross-sectional view taken along FIG. 3 B-B' in FIG. 5A is a potential diagram along FIG. 4A X-X' and Y-Y' in FIG. 5B is a potential diagram along FIG. 4A V-V' in FIG. 5C is a potential diagram along FIG. 4B W-W' in

[0089] FIG. 3 Four pixels including two pixels in a first direction in a plan view and two pixels in a second direction orthogonal to the first direction are shown. It can be mentioned that the first direction refers to a direction along a pixel row (row direction). That is, the first direction refers to a direction corresponding to a direction observed from one pixel to another pixel in the case where a plurality of pixels are present in a first row. Further, it can be mentioned that the second direction refers to a direction along a pixel column (column direction). A direction intersecting the first direction and the second direction refers to a third direction. Hereinafter, for the convenience of description, in FIG. 3 , an avalanche diode of a first row and a first column is referred to as a first avalanche diode, an avalanche diode of a first row and a second column is referred to as a second avalanche diode, and an avalanche diode of a second row and a second column is referred to as a third avalanche diode. According to the present embodiment, a pixel is constituted by a counter and a sensitivity region for generating a signal to be read from a single counter. In the present specification, a "plan view" refers to a view in a direction perpendicular to a plane parallel to a light incident surface of a substrate.

[0090] As shown in FIG. 4A and FIG. 4B , an avalanche diode is formed inside a substrate 40. The substrate 40 has a first surface 40A and a second surface 40B opposite to the first surface 40A. The first surface 40A is a surface on which a contact plug 6 and a contact plug 7 are formed. Further, a gate electrode of a transistor can be disposed on the first surface 40A side. The description will be provided assuming that light is incident from the second surface 40B side of the substrate 40, but light can be incident from the first surface 40A side of the substrate 40. In the present specification, "depth" refers to a depth from the first surface 40A toward the second surface 40B.

[0091] Each avalanche diode has at least a semiconductor region of a first conductivity type (N-type semiconductor region 1) formed at a first depth and a semiconductor region of a second conductivity type (P-type semiconductor region 5) formed at a second depth deeper than the first depth from the first surface. The N-type semiconductor region 1 and the P-type semiconductor region 5 (the seventh semiconductor region) form a P-N junction. The P-type semiconductor region 5 is, for example, a well region.

[0092] The contact plug 6 that supplies the potential VH via the quenching element 202 is connected to the N-type semiconductor region 1. The contact plug 7 that supplies the potential VL is connected to the P-type semiconductor region 4. The potential VL is supplied to the P-type semiconductor region 5 via the contact plug 7 and the P-type semiconductor region 4.

[0093] In a cross section that passes through the plurality of N-type semiconductor regions 1, the first isolation portion 20 is arranged between the N-type semiconductor regions 1 and the N-type semiconductor regions 1. In addition, in a cross section different from the above-described specific cross section, the second isolation portion 30 is arranged between the N-type semiconductor regions 1 and the N-type semiconductor regions 1. For example, in FIG. 3 and FIG. 4A-FIG. 4B In a cross section that passes through the N-type semiconductor region 1 of the first avalanche diode and the N-type semiconductor region 1 of the second avalanche diode, the first isolation portion 20 is arranged between the respective N-type semiconductor regions. In a cross section that passes through the N-type semiconductor region 1 of the second avalanche diode and the N-type semiconductor region 1 of the third avalanche diode, the first isolation portion 20 is arranged between the respective N-type semiconductor regions 1. In a cross section that passes through the N-type semiconductor region 1 of the first avalanche diode and the N-type semiconductor region 1 of the third avalanche diode, the second isolation portion 30 is arranged between the respective N-type semiconductor regions 1. The second isolation portion 30 includes at least the P-type semiconductor region 4.

[0094] As shown in FIG. 5A , the difference between the potential height with respect to electrons in the N-type semiconductor region 3 and the potential height with respect to electrons in the P-type semiconductor region 5 is smaller than the difference between the potential height with respect to electrons in the N-type semiconductor region 1 and the potential height with respect to electrons in the P-type semiconductor region 5. The difference between the potential height with respect to electrons in the N-type semiconductor region 1 and the potential height with respect to electrons in the P-type semiconductor region 5 along X-X' is configured so that avalanche multiplication can be performed. The difference between the potential height with respect to electrons in the first isolation portion 20 and the potential height with respect to electrons in the P-type semiconductor region 5 along Y-Y' is configured so that avalanche multiplication is not caused. The maximum potential height with respect to electrons along Y-Y' is lower than the maximum potential height with respect to electrons along X-X'.

[0095] FIG. 5B and FIG. 5CThe potential distribution with respect to the signal charge along V-V' and the potential distribution with respect to the signal charge along W-W' are shown. According to the present embodiment, in a state in which the potential of the stable avalanche diode is waiting for a photon (static), the potential height of the N-type semiconductor region 1 with respect to the signal charge is in the lowest state. Then, when a state in which a photon or a dark charge is detected and causes avalanche multiplication in the avalanche diode is established (quenching), the potential height of the N-type semiconductor region 1 with respect to the signal charge gradually increases. The height of the potential barrier in the first isolation portion 20 is preferably higher than the potential height of the N-type semiconductor region 1 with respect to the signal charge when avalanche multiplication is caused. This is because, in this way, it is possible to reduce the charge crosstalk between adjacent avalanche diodes and contribute to functioning as an isolation portion. Note that, in a case where it is not necessary to increase the resolution of the photoelectric conversion device, the potential barrier can not be formed in the first isolation portion 20. That is, in a state in which avalanche multiplication is to be caused, the potential height of the first isolation portion 20 can be substantially the same as the potential height of the N-type semiconductor region 1.

[0096] According to the present embodiment, the potential barrier formed by the first isolation portion 20 is lower than the potential barrier formed by the second isolation portion 30. Also in this case, the reduction of the pixel size contributes to reducing the crosstalk. The reason will be described below while comparing the photoelectric conversion device described in Patent Document 1 with the comparative example shown in FIG. 6A-FIG. 6B

[0097] In the comparative example shown in FIG. 6A , the N-type semiconductor region 3 is arranged between the N-type semiconductor region 1 and the N-type semiconductor region 1. In addition, the N-type semiconductor region 3 is arranged so as to sandwich the P-type semiconductor region 8.

[0098] In the photoelectric conversion device described in Patent Document 1, the P-type semiconductor region having a high impurity concentration is arranged so as to surround the entire circumference of the N-type semiconductor region constituting the avalanche diode in a plan view. In this case, each semiconductor region needs to be arranged at a predetermined distance to secure the withstand voltage between the N-type semiconductor region and the P-type semiconductor region. Therefore, the N-type semiconductor regions of each avalanche diode cannot be close to each other, and it is not possible to reduce the pixel pitch.

[0099] In addition, in the photoelectric conversion device shown in the comparative example, the impurity concentration of the P-type semiconductor region 8 is low, but the P-type semiconductor region is still a neutral region. Therefore, as shown in FIG. 6B , the potential with respect to the signal charge along Y-Y' increases as Y is approached. In this structure, the electrons generated in the region between the P-type semiconductor region 8 and the P-type semiconductor region 11 are also read as signal charges. That is, in the semiconductor region 13 between the P-type semiconductor region 8 and the P-type semiconductor region 11, it is not possible to separate the sensitivity region for each N-type semiconductor region 1. ​

[0100] Note that, when used only in this specification, the term "impurity concentration" refers to a net impurity concentration compensated by impurities of the reverse conduction type impurities. That is, the "impurity concentration" refers to the NET concentration. A region in which the P-type added impurity concentration is higher than the N-type added impurity concentration is a P-type semiconductor region. In contrast, a region in which the N-type added impurity concentration is higher than the P-type added impurity concentration is an N-type semiconductor region.

[0101] According to the present embodiment, a region between the N-type semiconductor regions 1 in which the semiconductor region is depleted is arranged as a first isolation portion 20 between the plurality of N-type semiconductor regions 1. Since the first isolation portion 20 is depleted, as shown in FIG. 6, the potential distribution along Y-Y' decreases from the P-type semiconductor region 5 toward the first isolation portion 20. In other words, the potential distribution along Y-Y' monotonically decreases from the P-type semiconductor region toward the first isolation portion 20. Thus, a state in which the charges also flow toward the first isolation portion 20 is established. The charges that have flowed toward the first isolation portion 20 flow through the N-type semiconductor region 1, but since the potential difference between the N-type semiconductor region 1 and the first isolation portion 20 is a potential difference of such a degree that does not cause avalanche multiplication, an avalanche current is not generated and is not counted by the counter circuit. Thus, the potential difference is not read as a signal. That is, not only the first isolation portion 20, but also a region between the first isolation portion 20 and the second face also substantially functions as a dead zone, and can be used as an isolation portion. Thus, even when the pixel pitch is reduced, a signal can be read for each pixel while reducing crosstalk. FIG. 5A According to the present embodiment, an N-type semiconductor region 3 in which the impurity concentration is lower than the N-type semiconductor region 1 is arranged as the first isolation portion 20. In other words, a configuration is adopted in which, instead of surrounding the entire periphery of the N-type semiconductor region 1 in a plan view by the P-type semiconductor region 4, the P-type semiconductor region 4 is arranged in a part of the periphery of the N-type semiconductor region 1, and the P-type semiconductor region 4 is not arranged in the other part. That is, a configuration is adopted in which the P-type semiconductor region 4 in which the withstand voltage needs to be ensured is arranged only partially, and in the other part, the height of the potential barrier is set to a degree at which signal charges do not leak. Not limited thereto, as in the embodiment to be described below, the P-type semiconductor region 4 and the N-type semiconductor region 3 arranged to sandwich the P-type semiconductor region 4 can be arranged as the first isolation portion 20, as long as the first isolation portion 20 is depleted. Further, an intrinsic semiconductor region (i-type semiconductor region) can be arranged in at least a part thereof. Further, only the P-type semiconductor region 4 can be arranged between the N-type semiconductor regions 1.

[0102]

[0103] ​The length of the first isolation portion 20 in the first direction is shorter than the length of the second isolation portion 30 in the third direction. In other words, the distance between the N-type semiconductor regions 1 in the first direction is shorter than the distance between the N-type semiconductor regions 1 in the third direction. For example, the ratio of the length of the first isolation portion 20 to the length of the second isolation portion 30 is less than 1 and equal to or greater than 1 / 8. For example, the distance between the avalanche multiplication portions in the first direction is preferably 1 μm or more. In order to ensure the withstand voltage, the distance between the avalanche multiplication portions in the first direction can be set to 0.5 μm or more, and is preferably set to 1 μm or more. On the other hand, in order to reduce the area of the pixel region, the distance between the avalanche multiplication portions in the first direction can be set to 10 μm or less, and is preferably set to 4 μm or less.

[0104] The impurity concentration of the N-type semiconductor region 3 is preferably lower than the impurity concentration of the P-type semiconductor region 5 arranged at a position overlapping the N-type semiconductor region 3 in a plan view. In this way, the N-type semiconductor region 3 can be depleted in the longitudinal direction toward the second face. For example, the impurity concentration of the N-type semiconductor region 3 differs by a factor of 2 or more with respect to the impurity concentration of the P-type semiconductor region 5. The impurity concentration of the N-type semiconductor region 3 is set to 1E18 cm -3 or less, for example. The N-type semiconductor region 3 preferably satisfies the following expression (2). In the following expression (2), the impurity concentration of the N-type semiconductor region 3 is set to the impurity concentration Nd2, the impurity concentration of the P-type semiconductor region 5 is set to Na2, and the elementary charge is set to q. Furthermore, the dielectric constant of the semiconductor is set to ε, the potential difference between the P-N junction of the N-type semiconductor region 3 and the P-type semiconductor region 5 is set to the potential difference V, and the depth of the N-type semiconductor region 3 is set to H. Here, the depth refers to the thickness of the N-type semiconductor region 3 in the direction from the first face toward the second face.

[0105] [Expression 2]

[0106]

[0107] The N-type semiconductor region 3 is shared by a plurality of avalanche diodes adjacent thereto. The second isolation portion 30 is constituted by the N-type semiconductor region 3 and the P-type semiconductor region 4.

[0108] The N-type semiconductor region 2 having an impurity concentration lower than that of the N-type semiconductor region 1 is preferably arranged between the N-type semiconductor region 1 and the P-type semiconductor region 4. In this way, it is facilitated to move the electric charge in the vicinity of the N-type semiconductor region 2 to a position in the N-type semiconductor region 1 close to the contact plug 6. The N-type semiconductor region 2 can be set to have the same impurity concentration as the N-type semiconductor region 3.

[0109] In FIG. 4A andFIG. 4B In this case, the N-type semiconductor region 2 and the P-type semiconductor region 4 are in contact with each other, but the N-type semiconductor region 2 and the P-type semiconductor region 4 can be physically separated from each other. In addition, in order to improve the withstand voltage between the N-type semiconductor region 2 and the P-type semiconductor region 4, trench isolation can be applied between the N-type semiconductor region 2 and the P-type semiconductor region 4. For example, STI (Shallow Trench Isolation) can be applied between the N-type semiconductor region 2 and the P-type semiconductor region 4.

[0110] Note that, FIG. 4A and FIG. 4B A configuration in which the P-type semiconductor region 5 having no impurity concentration gradient is arranged is shown, but the P-type semiconductor region 5 can be a region having an impurity concentration gradient. For example, a configuration in which the impurity concentration at a depth deeper than a certain depth is set to be higher than the impurity concentration at the certain depth can be employed.

[0111] In this case, the impurity region of the first conductivity type or the second conductivity type for adjusting the electric field of the P-N junction can be arranged directly below the N-type semiconductor region 1.

[0112] In FIG. 4A and FIG. 4B In the case where two avalanche diodes aligned in the first direction or the second direction share the semiconductor region 3, but three or more avalanche diodes aligned in the first direction or the second direction can share the N-type semiconductor region 3.

[0113] Further, in FIG. 4A and FIG. 4B In the case where the P-type semiconductor region 4 and the contact plug 7 are arranged between each N-type semiconductor region 1 in the third direction, but the P-type semiconductor region 4 and the contact plug 7 can be sparsely arranged.

[0114] In FIG. 3 and FIG. 4A-FIG. 4B In the case where the distance between the four contact plugs 6 is equal to or greater than LC and the distance between the four contact plugs 6 and the contact plug 7 is equal to or less than LC in a plan view, L represents the distance between the contact plugs 7 aligned in the first direction, and LC is L / √2. In other words, in FIG. 3 and FIG. 4A-FIG. 4BIn this configuration, contact plugs 7 are arranged at a distance equal to or less than LC relative to all four contact plugs 6. In this way, while the distances between the N-type semiconductor regions 1 and P-type semiconductor regions 4 of each avalanche diode are equally spaced, contact plugs 7 can be shared by the avalanche diodes. The distance between contact plugs can be, for example, the shortest distance between contact plugs. For example, in the case where multiple contact plugs are connected to the P-type semiconductor region 4 and multiple contact plugs 6 are connected to the N-type semiconductor region 1, it is sufficient for the contact plugs 6 and 7 at the shortest distance to satisfy the above expression. The shortest distance between the N-type semiconductor region 1 of each avalanche diode and the contact plug 7 closest to the N-type semiconductor region 1 is preferably set to an equal interval.

[0115] In addition, such as FIG. 3 and FIG. 4A-FIG. 4B As shown, in the top view, contact plugs 7, 6, 7, 6, and 7 are arranged sequentially along the third direction. Along the cross-section of the third direction, contact plug 7, P-type semiconductor region 5, N-type semiconductor region 2, N-type semiconductor region 1, and N-type semiconductor region 2 are arranged sequentially. Next, contact plug 7, N-type semiconductor region 3, N-type semiconductor region 1, N-type semiconductor region 3, P-type semiconductor region 5, and contact plug 7 are arranged sequentially. In this manner, according to this embodiment, when contact plug 7 is shared by avalanche diodes, each structure is arranged symmetrically with each other in the third direction. This reduces the fluctuation of signal readout between avalanche diodes.

[0116] <Second Embodiment>

[0117] Will use FIG. 7 and FIG. 8 The structure of the photoelectric conversion device according to the second embodiment is described. The second embodiment differs from the first embodiment in that the first isolation portion 20 is composed of an N-type semiconductor region 3 and a P-type semiconductor region 8 with a lower impurity concentration than the P-type semiconductor region 4. Items other than those described below can be constructed in a manner substantially similar to the first embodiment.

[0118] Also according to this embodiment, the height of the barrier formed by the second isolation portion 30 is higher than the height of the barrier formed by the first isolation portion 20. Furthermore, also according to this embodiment, the first isolation portion 20 is configured to be completely depleted.

[0119] The impurity concentration in region 8 of the P-type semiconductor is lower than that in region 4 of the P-type semiconductor.

[0120] The condition in the configuration in which the P-type semiconductor region 8 is to be completely depleted is shown in the following expression (3). Here, the impurity concentration of the N-type semiconductor region 3 is set to Nd, the impurity concentration of the P-type semiconductor region 8 is set to Na, and the elementary charge is set to q. Further, the dielectric constant of the semiconductor is set to ε, the potential difference between the P-N junction of the N-type semiconductor region 3 and the P-type semiconductor region 8 is set to V, and the length of the P-type semiconductor region 8 sandwiched by the N-type semiconductor region 3 is set to D.

[0121] [Expression 3]

[0122]

[0123] In the above expression (3), the dimension of D is [m], the dimension of q is [C], the dimensions of Nd and Na are [m -3 ], the dimension of ε is [F / m], and the dimension of V is [V]. That is, when the dimensions of the above expression (3) are extracted, the following expression (4) holds.

[0124] [Expression 4]

[0125]

[0126] Further, since [C] = [F][V] due to Q = CV, the following expression (5) holds when the above expression (4) is expanded.

[0127] [Expression 5]

[0128]

[0129] In the FIG. 8 , the N-type semiconductor region 3 and the P-type semiconductor region 8 are formed at the same depth, but the P-type semiconductor region 8 can be formed at a position shallower than the N-type semiconductor region 3. Further, the P-type semiconductor region 8 is configured to constitute a part of the first face 40A, but can be formed away from the first face 40A.

[0130] In the FIG. 8 , the P-type semiconductor region 8 does not have an impurity concentration gradient, but can have an impurity concentration gradient in at least one of the direction parallel to the first face 40A and the depth direction.

[0131] Also according to the present embodiment, similarly to the first embodiment, compared to Patent Literature 1, it is possible to reduce the pixel pitch. Further, since it is possible to be configured such that the electric charge generated in the region between the first isolation portion 20 and the second face is not read as a signal, it is possible to divide the sensitive region for each N-type semiconductor region 1, and it is possible to separate the signals.

[0132] <Third Embodiment>

[0133] Will use FIG. 9 to FIG. 11 The structure of the photoelectric conversion device according to the third embodiment is described. The third embodiment differs from the first embodiment in that the first isolation portion 20 is composed of an N-type semiconductor region 3 and a trench isolation portion 9. Except for the items described below, the components can be constructed in a substantially similar manner to the first embodiment.

[0134] FIG. 9 This is a partially enlarged top view of the pixel region of the photoelectric conversion device according to the third embodiment. FIG. 10 and FIG. 11 It is along FIG. 9 A schematic cross-sectional view taken from A-A' in the diagram.

[0135] It can be done as follows FIG. 10 The STI shown or as FIG. 11 The DTI (deep trench isolation) shown forms a trench isolation portion 9. For example, one end of the trench isolation portion 9 is formed at a depth greater than that of the N-type semiconductor region 1.

[0136] At least one of the following: a dielectric material formed of oxide, polycrystalline silicon arranged via a dielectric film, and a metal, is embedded in a trench isolation portion 9.

[0137] Impurity regions of a first conductivity type can be disposed on the side of the trench isolation portion 9. These impurity regions of the first conductivity type are used to deactivate defects that may form at the interface between the trench isolation portion 9 and the semiconductor region 3.

[0138] Furthermore, in the case of a back-illuminated sensor, a groove can be formed from the second side.

[0139] Similarly, according to this embodiment, as in the first embodiment, the pixel pitch can be reduced compared to Patent Document 1. Furthermore, when the trench isolation portion 9 is formed using DTI, color mixing between adjacent pixels caused by the light emission from the avalanche diode can be reduced.

[0140] Fourth embodiment

[0141] Will use FIG. 12 and FIG. 13The configuration of the photoelectric conversion device according to the fourth embodiment will be described. According to the fourth embodiment, the avalanche diode is constituted by the N-type semiconductor region 1, the N-type semiconductor region 10, and the P-type semiconductor region 11. The P-type semiconductor region 11 is also provided at a position deeper than the N-type semiconductor regions 2 and 3 and the P-type semiconductor region 5. In addition, the P-type semiconductor region 4 and the P-type semiconductor region 11 are coupled to each other via the P-type semiconductor region 5. The configuration other than this is similar to that of the first embodiment. The items other than the items to be described below can basically adopt the configuration similar to that of the first embodiment.

[0142] The N-type semiconductor region 10 is a semiconductor region having a lower impurity concentration than the N-type semiconductor region 1. In addition, the N-type semiconductor region 10 is a semiconductor region having a higher impurity concentration than the N-type semiconductor region 3. When the N-type semiconductor region 10 is formed between the N-type semiconductor region 1 and the P-type semiconductor region 11, the intensity of the electric field generated between the N-type semiconductor region 1 and the P-type semiconductor region 11 can be adjusted. In addition, since the N-type semiconductor region 10 is arranged, it is helpful to detect photocharges generated in the deep portion compared to the first embodiment, and it is possible to improve the long-wavelength sensitivity.

[0143] The P-type semiconductor region 11 is arranged continuously from a position below one contact plug 7 to a position below the other contact plug 7 in a certain cross section. Since the P-type semiconductor region 11 is arranged, it is possible to prevent unnecessary signal charges that can be generated on the second face 40B of the substrate from being read to the N-type semiconductor region 1. In FIG. 12 In the fourth embodiment, two groups of four avalanche diodes are arranged in the partition region partitioned by the P-type semiconductor regions 4, 5, and 11.

[0144] The P-type semiconductor region 5 can supply a potential to the P-type semiconductor region 11 via the P-type semiconductor region 4. The P-type semiconductor region 5 is a semiconductor region having a lower impurity concentration than the P-type semiconductor region 4.

[0145] The P-type semiconductor region 11 can have a concentration gradient in the depth direction. In addition, in FIG. 12 In the fourth embodiment, a trench isolation portion for securing a withstand voltage can be arranged between the P-type semiconductor region 4 and the N-type semiconductor region 2.

[0146] Also according to the present embodiment, similar to the first embodiment, it is possible to reduce the pixel pitch compared to Patent Literature 1. In addition, compared to the first embodiment, it is helpful to detect photocharges generated in the deep portion, and it is possible to improve the long-wavelength sensitivity.

[0147] <5th Embodiment>

[0148] The use of FIG. 14The configuration of the photoelectric conversion device according to the fifth embodiment will be described. According to the fifth embodiment, the first isolation portion 20 is constituted by the N-type semiconductor region 3 and the P-type semiconductor region 8. Since the P-type semiconductor region 8 is similar to the P-type semiconductor region 8 of the second embodiment, the description thereof will be omitted. In addition, since the configuration other than the first isolation portion 20 is the same as described according to the fourth embodiment, the description thereof will be omitted.

[0149] Also according to the present embodiment, similarly to the first embodiment, it is possible to reduce the pixel pitch as compared with Patent Literature 1. In addition, as compared with the first embodiment, it is helpful to detect photocharges generated in the deep portion, and it is possible to improve the long-wavelength sensitivity.

[0150] <Sixth Embodiment>

[0151] The configuration of the photoelectric conversion device according to the sixth embodiment will be described. FIG. 15 and FIG. 16 The configuration of the photoelectric conversion device according to the sixth embodiment will be described. FIG. 15 is a partial enlarged plan view of a pixel region of the photoelectric conversion device according to the sixth embodiment. FIG. 16 is a schematic cross-sectional view taken along A-A' in FIG. 15 According to the sixth embodiment, a P-type semiconductor region for physically separating the sensitivity regions of the respective pixels is arranged. In addition, the P-type semiconductor region 12 is arranged between the N-type semiconductor region 1 and the P-type semiconductor region 11, and the photoelectric conversion region 13 is arranged between the P-type semiconductor region 12 and the P-type semiconductor region 11. Furthermore, the P-type semiconductor region 5 is arranged between the first isolation portion 20 and the P-type semiconductor region 11. The configuration other than this is similar to the fourth embodiment. Items other than the items to be described below can basically adopt a configuration similar to the fourth embodiment.

[0152] The P-type semiconductor region 12 forms a P-N junction with the N-type semiconductor region 1. It is possible to cause avalanche multiplication in the vicinity of this P-N junction. The P-type semiconductor region 12 is continuously arranged from one P-type semiconductor region 5 to another P-type semiconductor region 5 in the cross-sectional view.

[0153] The photoelectric conversion region 13 is arranged between the P-type semiconductor region 12 and the P-type semiconductor region 11.

[0154] The photoelectric conversion region 13 is constituted by an N-type semiconductor region having a lower impurity concentration than the N-type semiconductor region 1 or a P-type semiconductor region having a lower impurity concentration than the P-type semiconductor region 5 and the P-type semiconductor region 11.

[0155] In FIG. 15 , the P-type semiconductor region 4 and the N-type semiconductor region 2 are separated from each other, but the P-type semiconductor region 4 and the N-type semiconductor region 2 can be in contact with each other.

[0156] Similarly, according to this embodiment, as in the first embodiment, the pixel pitch can be reduced compared to Patent Document 1. Furthermore, according to this embodiment, since the photoelectric conversion region is physically separated from the P-type semiconductor region 5, it helps to reduce charge crosstalk. In addition, since the avalanche multiplication region can be reduced compared to the first embodiment, dark current can be reduced while maintaining sensitivity.

[0157] <Seventh Embodiment>

[0158] Will use FIG. 17 and FIG. 18 The structure of the photoelectric conversion device according to the seventh embodiment is described. FIG. 17 This is a partially enlarged top view of the pixel region of the photoelectric conversion device according to the seventh embodiment. FIG. 18 It is along FIG. 17 A schematic cross-sectional view taken along line A-A'. According to the seventh embodiment, the first isolation portion 20 is composed of an N-type semiconductor region 3 and a P-type semiconductor region 8. Furthermore, P-type semiconductor regions 14 are arranged between P-type semiconductor regions 12 in a direction parallel to the first surface, and N-type semiconductor regions 15 are arranged between the photoelectric conversion regions. The rest of the construction is similar to that of the sixth embodiment. Except for the items described below, the items are substantially similar to those of the sixth embodiment.

[0159] In the top view, the P-type semiconductor region 14 is surrounded by the P-type semiconductor region 12. The P-type semiconductor region 14 is a P-type semiconductor region with a lower impurity concentration than the P-type semiconductor region 12. The P-type semiconductor region 14 and the N-type semiconductor region 1 form a PN junction, and the signal charge undergoes avalanche multiplication near the PN junction. Compared to the P-type semiconductor region 12, the P-type semiconductor region 14 has a lower potential height relative to electrons. Therefore, the generated signal charge is easily concentrated in the P-type semiconductor region 14 and easily crosses the PN junction interface between the P-type semiconductor region 14 and the N-type semiconductor region 1.

[0160] N-type semiconductor region 15 is disposed between P-type semiconductor region 14 and P-type semiconductor region 11. The impurity concentration of N-type semiconductor region 15 is lower than that of semiconductor region 1. When semiconductor region 14 is an N-type semiconductor region, the impurity concentration is set to be lower than that of semiconductor region 14.

[0161] Also according to this embodiment, similar to the first embodiment, the pixel pitch can be reduced compared to Patent Document 1. Furthermore, similar to the sixth embodiment, charge crosstalk can be suppressed. In addition, it helps to concentrate the charge in the N-type semiconductor region 1.

[0162] <Eighth Embodiment>

[0163] Will useFIG. 19 An opto-electric conversion device according to an eighth embodiment will be described. In the opto-electric conversion device according to the present embodiment, a substrate of an avalanche diode 201 of a pixel 110 and a substrate in which a counter circuit 204 and a quenching element 202 are arranged are separated from each other. Then, the opto-electric conversion device is constituted by laminating and bonding the substrates. FIG. 2 The substrate of the avalanche diode 201 of the pixel 110 and the substrate in which the counter circuit 204 and the quenching element 202 are arranged are separated from each other. Then, the opto-electric conversion device is constituted by laminating and bonding the substrates.

[0164] According to the present embodiment, each microlens is arranged to overlap each avalanche diode in a plan view.

[0165] FIG. 19 A state in which light is incident from a second face side corresponding to a face of a side to which a contact plug is not connected is shown. Therefore, the microlens 18 and the color filter 19 are arranged on one side of the second face of the substrate 16. In a case where light is made incident from the first face side of the substrate 16, the microlens 18 and the color filter 19 are arranged on the first face side.

[0166] Also according to the present embodiment, similarly to the first embodiment, compared with Patent Literature 1, it is possible to reduce the pixel pitch. In addition, by arranging the circuit portion on one side of the substrate 17, it is possible to reduce the area of the substrate 16.

[0167] In the opto-electric conversion device according to the seventh embodiment, the avalanche diode described according to the seventh embodiment is adopted in addition to the above-described configuration. Note that the avalanche diode described according to the first embodiment to the sixth embodiment can be adopted. In this case, similarly to the opto-electric conversion device according to the seventh embodiment, the contact plug 6 is connected to the N-type semiconductor region 1 described in each embodiment. FIG. 19 FIG. 19

[0168] <Ninth Embodiment>

[0169] An opto-electric conversion device according to a ninth embodiment will be described. The opto-electric conversion device according to the present embodiment is configured so that light that has passed through a single microlens is incident on a plurality of avalanche diodes. The configuration other than this is similar to the seventh embodiment. FIG. 20 According to the present embodiment, it is possible to perform depth detection while reducing the pixel pitch.

[0170] <Tenth Embodiment>

[0171] An opto-electric conversion system using the opto-electric conversion device according to each embodiment will be described. The opto-electric conversion system according to the present embodiment is configured so that light that has passed through a single microlens is incident on a plurality of avalanche diodes. The configuration other than this is similar to the seventh embodiment.

[0172] A non-visible light detection system and a medical diagnosis system such as PET corresponding to the example of the light detection system will be described. Portions having functions similar to those of the opto-electric conversion device according to the seventh embodiment are given similar reference numerals, and detailed description thereof will be omitted. Note that the pixel of the present embodiment has a TDC and a memory instead of the counter circuit 204 and the quenching element 202. FIG. 21 FIG. 21 FIG. 1 to FIG. 20 Note that the pixel of the present embodiment has a TDC and a memory instead of the counter circuit 204 and the quenching element 202.​​​​FIG. 2 The counter circuit is a TDC 206. Here, a description will be provided in which the TDC is set to the TDC 206 and the memory is set to the memory 207.

[0173] FIG. 21 is a block diagram for describing the configuration of the non-visible light detection system. The non-visible light detection system has a wavelength conversion section 301 and a data processing section 307, and has a plurality of photoelectric conversion devices 1010.

[0174] The irradiation object 300 emits light of a wavelength band corresponding to non-visible light. The wavelength conversion section 301 receives the light of the wavelength band corresponding to non-visible light emitted from the irradiation object 300, and emits visible light.

[0175] The avalanche diode 201, on which the visible light emitted from the wavelength conversion section 301 is incident, performs photoelectric conversion. Then, the photoelectric conversion device 1010 holds a digital signal based on a signal according to photoelectric conversion charge in the memory 207 via the control section 208, the waveform shaping section 203, and the TDC 206. The plurality of photoelectric conversion devices 1010 can be formed as a single device, or can be formed by an array of a plurality of devices.

[0176] The plurality of digital signals held in the memories 207 of the plurality of photoelectric conversion devices 1010 are subjected to signal processing by the data processing section 1207. Here, as a signal processing section, a synthesis process of a plurality of images obtained from the plurality of digital signals is performed.

[0177] Next, the configuration of a medical diagnosis system such as PET will be described as a specific example of the non-visible light detection system.

[0178] The subject corresponding to the irradiation object 300 releases pairs of radioactive rays from the inside of a living body. The wavelength conversion section 301 constitutes a scintillator, and the scintillator emits visible light upon incidence of the pairs of radioactive rays released from the subject.

[0179] The avalanche diode 201 on which the visible light emitted from the scintillator is incident performs photoelectric conversion, and the photoelectric conversion device 1010 holds a digital signal based on a signal according to photoelectric conversion charge in the memory 207 via the control section 208, the waveform shaping section 203, and the TDC 206. That is, the photoelectric conversion device 1010 is arranged to detect the arrival time of the pairs of radioactive rays released from the subject, and to detect the visible light emitted from the scintillator to hold a digital signal in the memory 207.

[0180] In the data processing section 1207, signal processing is performed on the digital signals held in the memories 207 of the plurality of photoelectric conversion devices 1010. Here, synthesis processing such as image reconstruction is performed as a signal processing section that forms an image of the inside of the living body of the subject using a plurality of images obtained from a plurality of digital signals.

[0181] <Eleventh Embodiment>

[0182] FIG. 22 is a block diagram showing the configuration of a photoelectric conversion system 1200 according to the present embodiment. The photoelectric conversion system 1200 of the present embodiment includes a photoelectric conversion device 1215. Here, any of the photoelectric conversion devices described in the above embodiments can be applied to the photoelectric conversion device 1215. The photoelectric conversion system 1200 can be used as, for example, an imaging system. Specific examples of the imaging system include a digital still camera, a digital video camera, a surveillance camera, and the like. FIG. 22 An example of a digital still camera as the photoelectric conversion system 1200 is shown.

[0183] FIG. 22 The photoelectric conversion system 1200 shown has the photoelectric conversion device 1215, a lens 1213 for imaging an optical image of a subject on the photoelectric conversion device 1215, an aperture 1214 for setting the amount of light passing through the lens 1213 to be variable, and a barrier 1212 for protecting the lens 1213. The lens 1213 and the aperture 1214 are optical systems for condensing light on the photoelectric conversion device 1215.

[0184] The photoelectric conversion system 1200 has a signal processing section 1216 that processes an output signal output from the photoelectric conversion device 1215. The signal processing section 1216 performs various types of correction and compression on an input signal as needed, and performs a signal processing operation on a signal to be output. The photoelectric conversion system 1200 also has a buffer memory section 1206 for temporarily storing image data, and an external interface section (external I / F section) 1209 for communicating with an external computer or the like. Further, the photoelectric conversion system 1200 has a recording medium 1211 (such as a semiconductor memory) for recording or reading imaging data, and a recording medium control interface section (recording medium control I / F section) 1210 for performing recording to or reading from the recording medium 1211. The recording medium 1211 can be built in the photoelectric conversion system 1200, or can be detachably attached to the photoelectric conversion system 1200. In addition, communication from the recording medium control I / F section 1210 to the recording medium 1211 and communication from the external I / F section 1209 can be performed wirelessly.

[0185] The photoelectric conversion system 1200 also has an overall control and computation section 1208 that performs various types of computation and also controls the entire digital still camera, and a timing generation section 1217 that outputs various types of timing signals to the photoelectric conversion device 1215 and the signal processing section 1216. Here, the timing signals and the like can be input from the outside, and it is sufficient that the photoelectric conversion system 1200 at least has the photoelectric conversion device 1215 and the signal processing section 1216 that processes the output signal output from the photoelectric conversion device 1215. As described according to the fourth embodiment, the timing generation section 1217 can be mounted on the photoelectric conversion device. The overall control and computation section 1208 and the timing generation section 1217 can be configured to realize part or all of the control functions of the photoelectric conversion device 1215.

[0186] The photoelectric conversion device 1215 outputs an image signal to the signal processing section 1216. The signal processing section 1216 performs predetermined signal processing on the image signal output from the photoelectric conversion device 1215 and outputs image data. Further, the signal processing section 1216 generates an image using the image signal. Further, the signal processing section 1216 can perform a ranging computation on the signal output from the photoelectric conversion device 1215. Note that the signal processing section 1216 or the timing generation section 1217 can be mounted on the photoelectric conversion device. That is, the signal processing section 1216 or the timing generation section 1217 can be provided on the substrate on which the pixels are arranged, or can have a configuration provided on another substrate. By constituting an imaging system using the photoelectric conversion device of each of the above-described embodiments, an imaging system capable of obtaining a higher quality image can be realized.

[0187] <Twelfth Embodiment>

[0188] A photoelectric conversion system and a movable object according to the present embodiment will be described using FIG. 23A-FIG. 23B and FIG. 24 A photoelectric conversion system and a movable object according to the present embodiment will be described using FIG. 23A-FIG. 23B A photoelectric conversion system and a movable object according to the present embodiment will be described using FIG. 24 is a flowchart showing the operation of a photoelectric conversion system according to the present embodiment. According to the present embodiment, as a photoelectric conversion system, an example of a vehicle-mounted camera is shown.

[0189] FIG. 23A-FIG. 23BAn example of a vehicle system and a photoelectric conversion system mounted thereon and performing image capturing is shown. The photoelectric conversion system 1301 includes a photoelectric conversion device 1302, an image pre-processing section 1315, an integrated circuit 1303, and an optical system 1314. The optical system 1314 images an optical image of a subject on the photoelectric conversion device 1302. The photoelectric conversion device 1302 converts the optical image of the subject imaged by the optical system 1314 into an electric signal. The photoelectric conversion device 1302 is any of the photoelectric conversion devices of the above-described respective embodiments. The image pre-processing section 1315 performs predetermined signal processing on a signal output from the photoelectric conversion device 1302. The function of the image pre-processing section 1315 can be embedded in the photoelectric conversion device 1302. At least two pairs of the optical system 1314, the photoelectric conversion device 1302, and the image pre-processing section 1315 are provided in the photoelectric conversion system 1301, and outputs from the image pre-processing sections 1315 of the respective pairs are input to the integrated circuit 1303.

[0190] The integrated circuit 1303 is an integrated circuit for an image capturing system, and includes an image processing section 1304 (including a memory 1305), an optical distance measuring section 1306, a distance measuring calculation section 1307, an object recognition section 1308, and an abnormality detection section 1309. The image processing section 1304 performs image processing such as development processing or defect correction on an output signal of the image pre-processing section 1315. The memory 1305 stores one-time storage of a captured image or a defect position of an image capturing pixel. The optical distance measuring section 1306 performs focusing or distance measurement of a subject. The distance measuring calculation section 1307 calculates distance measurement information from a plurality of pieces of image data obtained by a plurality of photoelectric conversion devices 1302. The object recognition section 1308 performs recognition of a vehicle, a road, a road sign, or a subject such as a person. When an abnormality of the photoelectric conversion device 1302 is detected, the abnormality detection section 1309 issues an abnormality alarm to a main control section 1313.

[0191] The integrated circuit 1303 can be realized by a specially designed hardware, can be realized by a software module, or can be realized by a combination thereof. In addition, the integrated circuit can be realized by an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like, or can be realized by a combination thereof.

[0192] The main control section 1313 manages and controls the operation of the photoelectric conversion system 1301, a vehicle sensor 1310, a control unit 1320, and the like. It is also possible to adopt a method in which the photoelectric conversion system 1301, the vehicle sensor 1310, and the control unit 1320 individually have a communication interface without the main control section 1313, and individually perform transmission and reception via a communication network (for example, CAN standard).

[0193] The integrated circuit 1303 has a function of transmitting a control signal or a setting value to the photoelectric conversion device 1302 by receiving the control signal from the main control section 1313 or by its own control section.

[0194] The photoelectric conversion system 1301 is connected with a vehicle sensor 1310, and can detect its own vehicle running state (such as vehicle speed, yaw rate, and rudder angle), as well as the state of the environment outside its own vehicle and other vehicles and obstacles. The vehicle sensor 1310 is also a distance information obtaining section configured to obtain distance information to an object. In addition, the photoelectric conversion system 1301 is connected with a driving assistance control section 1311 that performs various driving assistance such as automatic steering, automatic cruise, and collision avoidance functions. In particular, with respect to the collision determination function, collision estimation with other vehicles and obstacles and the presence or absence of collision are determined based on the detection results of the photoelectric conversion system 1301 and the vehicle sensor 1310. In this way, avoidance control in the case of estimating collision and safety device activation at the time of collision are performed.

[0195] In addition, the photoelectric conversion system 1301 is also connected with an alarm device 1312 that issues an alarm to the driver based on the determination result of the collision determination section. For example, in the case where the collision probability is high as a determination result of the collision determination section, the main control section 1313 performs vehicle control to avoid collision or mitigate damage by applying braking, releasing the accelerator, suppressing engine output, and the like. The alarm device 1312 issues a warning to the user by issuing an alarm such as a sound, displaying alarm information on the display section screen such as a car navigation system and an instrument panel, providing vibration to a seat belt or a steering wheel, and the like.

[0196] According to the present embodiment, the surroundings (for example, the front side or the rear side) of the vehicle will be photographed by the photoelectric conversion system 1301. FIG. 23B An arrangement example of the photoelectric conversion system 1301 in the case where the front side of the vehicle is to be photographed by the photoelectric conversion system 1301 is shown.

[0197] Two photoelectric conversion devices 1302 are arranged at the front side of the vehicle 1300. Specifically, it is preferable to adopt an arrangement in which the center line with respect to the front-rear orientation or the outer shape (for example, the vehicle width) of the vehicle 1300 is regarded as a symmetry axis to set the two photoelectric conversion devices 1302 to be linearly symmetrical with respect to the symmetry axis, to obtain distance information between the vehicle 1300 and an object to be photographed and determine the collision probability. In addition, the photoelectric conversion device 1302 is preferably arranged at a position where the driver's field of view is not disturbed when the driver visually recognizes the situation outside the vehicle 1300 from the driver's seat. The alarm device 1312 is preferably arranged so that the driver can easily see it.

[0198] Next, the use of the photoelectric conversion system 1301 will be described with reference to FIG. 10. FIG. 24The defect detection operation of the photoelectric conversion device 1302 in the photoelectric conversion system 1301 is described. The defect detection operation of the photoelectric conversion device 1302 is implemented in accordance with the steps S1410 to S1480 shown in FIG. 14. FIG. 24 The defect detection operation of the photoelectric conversion device 1302 is implemented in accordance with the steps S1410 to S1480 shown in FIG. 14.

[0199] Step S1410 is a step of setting at the start of the photoelectric conversion device 1302. That is, a setting for the operation of the photoelectric conversion device 1302 is transmitted from the outside of the photoelectric conversion system 1301 (for example, the main control section 1313) or the inside of the photoelectric conversion system 1301, and the imaging operation and the defect detection operation of the photoelectric conversion device 1302 are started.

[0200] Subsequently, in step S1420, a pixel signal is obtained from the effective pixels. Further, in step S1430, an output value from the defect detection pixels provided for detecting defects is obtained. Like in the effective pixels, the defect detection pixels similarly include a photoelectric conversion section. In the photoelectric conversion section, a predetermined voltage is written. The pixel output for detecting defects outputs a signal corresponding to the voltage written in the photoelectric conversion section. Note that step S1420 and step S1430 can be reversed.

[0201] Subsequently, in step S1440, a propriety determination between the expected output value of the defect detection pixels and the actual output value from the defect detection pixels is performed. As a result of the propriety determination in step S1440, in a case where the expected output value and the actual output value match, the processing step is transferred to step S1450, it is determined that the imaging operation is normally performed, and the processing step is transferred to step S1460. In step S1460, the pixel signals in the scanning row are transmitted to the memory 1305 and are preliminarily saved. Thereafter, the processing step returns to step S1420, and the defect detection operation is continued. On the other hand, as a result of the propriety determination in step S1440, in a case where the expected output value and the actual output value do not match, the processing step is transferred to step S1470. In step S1470, it is determined that there is an abnormality in the imaging operation, and an alarm is issued to the main control section 1313 or the alarm device 1312. The alarm device 1312 causes the display section to display that an abnormality has been detected. Thereafter, the photoelectric conversion device 1302 is stopped in step S1480, and the operation of the photoelectric conversion system 1301 ends.

[0202] Note that, according to the present embodiment, an example of the flowchart for each row has been illustrated, but the defect detection operation can be performed for a multi-row flowchart, or can be performed for each frame. In step S1470, the issuance of the alarm can be notified to the outside of the vehicle via a wireless network.

[0203] Further, according to the present embodiment, the control to avoid collision with other vehicles has been described, but the present embodiment can be applied to control to follow other vehicles autonomously, control to autonomously drive without deviating from a lane, and the like. Further, the photoelectric conversion system 1301 is not limited to a vehicle such as its own vehicle, but can be applied to a movable object (movable device) such as a ship, an airplane, or an industrial robot, for example. Further, the present embodiment can be applied not only to a movable object but also to an instrument that makes wide use of object recognition, such as an intelligent transport system (ITS).

[0204] The photoelectric conversion device of the present application can have a configuration capable of further obtaining various types of information such as distance information.

[0205] <Thirteenth Embodiment>

[0206] FIG. 25 is a block diagram showing a configuration example of a distance image sensor corresponding to an electronic instrument utilizing the photoelectric conversion device described according to the above-described embodiments.

[0207] As FIG. 25 indicated, the distance image sensor 401 is configured to include an optical system 402, a photoelectric conversion device 403, an image processing circuit 404, a monitor 405, and a memory 406. In addition, when light is projected from a light source device 411 to an object and light (modulated light or pulsed light) reflected on the surface of the object is received, the distance image sensor 401 can obtain a distance image according to the distance to the object.

[0208] The optical system 402 is configured to have one or a plurality of lenses and guide image light (incident light) from an object to the photoelectric conversion device 403 to form an image on a light-receiving surface (sensor portion) of the photoelectric conversion device 403.

[0209] The photoelectric conversion device of each of the above-described embodiments is used as the photoelectric conversion device 403, and a distance signal indicating a distance obtained according to a light-receiving signal output from the photoelectric conversion device 403 is supplied to the image processing circuit 404.

[0210] The image processing circuit 404 performs image processing based on the distance signal supplied from the photoelectric conversion device 403 to construct a distance image. Then, the distance image (image data) obtained by the image processing is supplied to the monitor 405 to be displayed or to the memory 406 to be stored (recorded).

[0211] In the distance image sensor 401 thus configured, by applying the above-described photoelectric conversion device along with improvement in characteristics of pixels, for example, a more accurate distance image can be obtained.

[0212] <Fourteenth Embodiment>

[0213] The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure can be applied to an endoscopic surgery system.

[0214] FIG. 26 is a drawing showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied.

[0215] FIG. 26 A situation in which an operator (a doctor) 1131 performs surgery on a patient 1132 on a patient bed 1133 using an endoscopic surgery system 1000 is shown. As shown in the drawing, the endoscopic surgery system 1000 is composed of an endoscope 1100, a surgical instrument 1110, and a cart 1140 loaded with various types of devices used for surgery under an endoscope.

[0216] The endoscope 1100 is composed of a lens barrel 1101 having a region of a predetermined length from a distal end to be inserted into a body cavity of the patient 1132, and a camera head 1102 connected to a proximal end of the lens barrel 1101. In the example shown in the drawing, an endoscope 1100 configured as a rigid scope having a rigid lens barrel 1101 is shown in the drawing, but the endoscope 1100 can be configured as a so-called flexible scope having a flexible lens barrel.

[0217] An opening portion into which an objective lens is fitted is provided at the distal end of the lens barrel 1101. A light source device 1203 is connected to the endoscope 1100, and light generated by the light source device 1203 is guided by a light guide extending inside the lens barrel 1101 to the distal end of the lens barrel, and is emitted to an observation object inside the body cavity of the patient 1132 via the objective lens. Note that the endoscope 1100 can be a direct vision scope, or an oblique or side vision scope.

[0218] An optical system and a photoelectric conversion device are provided inside the camera head 1102, and reflected light (observation light) from the observation object is collected on the photoelectric conversion device by the optical system. The observation light is photoelectrically converted by the photoelectric conversion device, and an electric signal corresponding to the observation light, that is, an image signal corresponding to an observation image is generated. The photoelectric conversion device described in each of the above-described embodiments can be used as the photoelectric conversion device. The image signal is sent to a camera control unit (CCU: camera control unit) 1201 as RAW data.

[0219] The CCU 1201 is composed of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and the like, and controls the operation of the endoscope 1100 and the display device 1202 in an integrated manner. Furthermore, the CCU 1201 receives the image signal from the camera head 1102, and applies various types of image processing, such as development processing (demosaicing processing), for displaying an image based on the image signal to the image signal.

[0220] The display device 1202 displays an image based on an image signal on which image processing has been applied by the CCU 1201, by control from the CCU 1201.

[0221] The light source device 1203 is constituted by, for example, a light source such as an LED (Light Emitting Diode), and supplies illumination light for capturing a surgical site or the like to the endoscope 1100.

[0222] The input device 1204 is an input interface for the endoscope surgery system 1000. A user can perform instruction input and input of various types of information to the endoscope surgery system 1000 via the input device 1204.

[0223] The surgical tool control device 1205 controls driving of the energy surgical tool 1112 for tissue cauterization, incision, vessel sealing, or the like.

[0224] The light source device 1203 that supplies illumination light for capturing a surgical site to the endoscope 1100 is constituted by a white light source constituted by, for example, an LED, a laser light source, or a combination thereof. In the case where the white light source is constituted by a combination of RGB laser light sources, since the output intensity and output timing of each color (each wavelength) can be controlled with high precision, adjustment of white balance of a captured image can be performed in the light source device 1203. In this case, the laser light from each RGB laser light source is emitted to an observation object in a time-division manner, and driving of the imaging element of the camera head 1102 is controlled in synchronization with the emission timing, so that an image corresponding to each of RGB can also be captured in a time-division manner. According to this method, even in the case where a color filter is not provided in the imaging element, a color image can be obtained.

[0225] Further, driving of the light source device 1203 can be controlled so that the intensity of the output light is changed every predetermined time. Driving of the imaging element of the camera head 1102 is controlled in synchronization with the timing for changing the intensity of the light, so that images are obtained in a time-division manner, and the images are synthesized, so that a high dynamic range image having no so-called black defect or white flare can be generated.

[0226] Further, the light source device 1203 can be configured to be able to supply light in a predetermined wavelength band corresponding to special light observation. In the special light observation, for example, the wavelength dependency of the absorption of light in the body system is utilized. Specifically, when light of a narrow band is emitted compared to the irradiation light at the time of normal observation, that is, white light, a predetermined tissue such as a mucosal surface layer portion is photographed with high contrast. Alternatively, in the special light observation, fluorescence observation can be performed in which an image is obtained by fluorescence generated at the time of emission of excitation light. In the fluorescence observation, fluorescence from the body system can be observed by emitting excitation light to the body system in such a manner that a reagent such as indocyanine green (ICG) is locally injected into the body system and excitation light corresponding to the fluorescence wavelength of the reagent is also emitted to the body system, or the like. The light source device 1203 can be configured to be able to supply narrow-band light and / or excitation light corresponding to the above-described special light observation.

[0227] FIG. 27 is a block diagram showing an example of the functional configuration of the camera head 1102 and the CCU 1201. FIG. 26

[0228] The camera head 1102 has a lens unit 1401, a photoelectric conversion device 1402, a driving section 1403, a communication section 1404, and a camera head control section 1405. The CCU 1201 has a communication section 1411, an image processing section 1412, and a control section 1413. The camera head 1102 and the CCU 1201 are connected by a transmission cable 1400 to be communicable with each other.

[0229] The lens unit 1401 is an optical system provided in the connection section with the barrel 1101. The observation light acquired from the distal end of the barrel 1101 is guided to the camera head 1102 and is incident on the lens unit 1401. The lens unit 1401 is configured by a combination of a plurality of lenses including a zoom lens and a focus lens.

[0230] ​The photoelectric conversion device of each of the above embodiments can be used as a photoelectric conversion device 1402. The photoelectric conversion device 1402 can be constituted by a single photoelectric conversion device, or can be constituted by a plurality of photoelectric conversion devices. In the case where the photoelectric conversion device 1402 is constituted by a plurality of photoelectric conversion devices, for example, an image signal corresponding to each of RGB can be generated by each photoelectric conversion device, and these image signals can be synthesized to obtain a color image. Alternatively, the photoelectric conversion device 1402 can be constituted to have a pair of photoelectric conversion devices for obtaining image signals for right and left eyes corresponding to 3D (dimensional) display, respectively. When 3D display is performed, the operator 1131 can more accurately grasp the depth of the living tissue at the surgical site. Note that in the case where the photoelectric conversion device 1402 is constituted by a plurality of photoelectric conversion devices, a system of a plurality of lens units 1401 can be provided in correspondence with each photoelectric conversion device.

[0231] The driving section 1403 is constituted by an actuator, and moves the zoom lens and the focus lens of the lens unit 1401 by a predetermined distance along the optical axis by control from the camera control section 1405. In this way, the magnification and the focus of the image captured by the photoelectric conversion device 1402 can be appropriately adjusted.

[0232] The communication section 1404 is constituted by a communication device configured to perform transmission and reception of various types of information with the CCU 1201. The communication section 1404 transmits the image signal obtained from the photoelectric conversion device 1402 to the CCU 1201 as RAW data via the transmission cable 1400.

[0233] Further, the communication section 1404 receives a control signal for controlling the driving of the camera head 1102 from the CCU 1201, and supplies the control signal to the camera control section 1405. The control signal includes, for example, information on the imaging conditions such as information indicating the specification of the frame rate of the captured image, information indicating the specification of the exposure value at the time of imaging, and / or information indicating the specification of the magnification and the focus of the captured image.

[0234] Note that the above imaging conditions such as the frame rate, the exposure value, the magnification, and the focus can be appropriately designated by the user, or automatically set by the control section 1413 of the CCU 1201 based on the obtained image signal. In the latter case, so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function are installed on the endoscope 1100.

[0235] The camera control section 1405 controls the driving of the camera head 1102 based on the control signal from the CCU 1201 received via the communication section 1404.

[0236] The communication section 1411 is constituted by a communication device configured to perform transmission and reception of various types of information with the camera head 1102. The communication section 1411 receives an image signal transmitted via the transmission cable 1400 from the camera head 1102.

[0237] In addition, the communication section 1411 transmits a control signal for controlling driving of the camera head 1102 to the camera head 1102. The image signal and the control signal can be transmitted by electric communication, optical communication, or the like.

[0238] The image processing section 1412 applies various types of image processing to an image signal corresponding to RAW data transmitted from the camera head 1102.

[0239] The control section 1413 performs various types of control related to imaging of a surgical site or the like by the endoscope 110 and display of a captured image obtained by the imaging of the surgical site or the like. For example, the control section 1413 generates a control signal for controlling driving of the camera head 1102.

[0240] In addition, the control section 1413 causes the display device 1202 to display a captured image in which the surgical site or the like is captured, on the basis of an image signal on which image processing is applied by the image processing section 1412. At this time, the control section 1413 can recognize various types of objects in the captured image using various types of image recognition technology. For example, the control section 1413 can recognize a surgical instrument such as forceps, a specific living body site, bleeding, fog when the energy surgical tool 1112 is used, or the like by detecting a shape, a color, or the like of an edge of an object included in the captured image. When the display device 1202 is caused to display the captured image, the control section 1413 can cause various types of surgical assistance information to be superimposed and displayed on an image of the surgical site using the recognition result. When the surgical assistance information is superimposed and displayed to be presented to the operator 1131, the burden on the operator 1131 can be reduced, and the operator 1131 can perform surgery with certainty.

[0241] The transmission cable 1400 that connects the camera head 1102 and the CCU 1201 is an electric signal cable corresponding to communication of an electric signal, an optical fiber corresponding to optical communication, or a composite cable thereof.

[0242] Here, in the example shown in the drawing, communication is performed in a wired manner using the transmission cable 1400, but communication between the camera head 1102 and the CCU 1201 can be performed wirelessly.

[0243] The above has described an example of an endoscopic surgery system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to the endoscope 1100, the camera head 1102 (the photoelectric conversion device 1402 thereof), and the like in the above-described configuration. By applying the technology according to the present disclosure to the endoscope 1100, the camera head 1102 (the photoelectric conversion device 1402 thereof), and the like, it is possible to reduce the influence of afterpulses generated by avalanche multiplication.

[0244] Note that, in this document, an endoscopic surgery system is described as an example, but the technology according to the present disclosure can be applied to other systems, such as a microscopic surgery system.

[0245] <15th Embodiment>

[0246] A photoelectric conversion system according to the 15th embodiment will be described. FIG. 28A-FIG. 28C and FIG. 29 A photoelectric conversion system according to the 15th embodiment will be described.

[0247] FIG. 28A is a diagram showing driving of a time-gated ToF (Time of Flight). Laser pulse light is emitted multiple times to an object that is a distance measurement target. Light reflected by the object is detected by a detector (the photoelectric conversion device described above) with a delay At. In a typical time-gated measurement, a gate window (a light detection period of the photoelectric conversion device) is shifted gradually to perform scanning, and information of consecutive frames is obtained. In the gate window at each position, photon counts are integrated N times. When the gate scanning is performed finely, the time resolution improves, but there is a disadvantage that the measurement time is prolonged.

[0248] FIG. 28B A measurement result converted into a histogram is shown. The histogram includes a photon count value of a background, and a value of a dark current component in a case where a reflected laser pulse is present outside the gate window. In the histogram, in a case where the peak intensity of the reflected light is greater than the count value of the background component, the profile of the count value of the reflected light is a rectangular distribution. This rectangular distribution has a width corresponding to the length of the gate window. The delay time At can be obtained from the rise or fall of the profile of the count value. The distance L from the object to the detector is calculated as L = cAt / 2. Here, c denotes the speed of light.

[0249] FIG. 28C A time-gated SPAD pixel is shown. A transistor serving as a quenching element 202 is connected to an avalanche diode 201. The quenching element 202 is an element configured to suppress electron avalanche (avalanche breakdown). When a global gate switch 280 is turned on from off, an output signal from the avalanche diode 201 is selectively output to a memory 281. The control pulse of the gate is about several nanoseconds, and is controlled in synchronization with irradiation of laser pulse light. The memory 281 provided for each pixel is provided in the vicinity of the pixel FIG. 2inside the counter circuit 204, and reads the signal stored in the memory 281 via the output section 282. Note that a certain voltage can be applied to the gate voltage VQ of the quenching element 202. In addition, in order to forcibly recharge the avalanche diode 201 before the global gate switch 280 becomes the on state, driving of a pulse signal input to VQ can be performed.

[0250] FIG. 29 The gate window curve, the reflected light distribution, and the detection intensity are shown. The detection intensity h(t) corresponds to a convolution calculation (convolution) of two functions. That is, the convolution of the gate window curve f(t) and the reflected light distribution g(t) corresponds to the detection intensity h(t). In FIG. 29 The top graph shows one reflection peak, and the bottom graph shows two reflection peaks. In an actual measurement environment, the detected intensity curve has a complex shape. For example, this is the case where laser light is emitted to an object via a translucent object (semi-reflective object), and the like. In this case, light reflected by the translucent object such as glass or transparent plastic and light transmitted through the translucent object and emitted to the object are both detected. FIG. 29 The bottom graph of FIG. 12 shows the above measurement example. Since the detection intensity h(t) is measurement data and the gate window curve f(t) is known, the reflected light distribution g(t) can be obtained by a deconvolution calculation (deconvolution). When the reflected light distribution g(t) can be obtained, distance information to the translucent object or the object can be obtained, and only distance information to the object can be separated.

[0251] This embodiment is a type of distance image sensor described according to the thirteenth embodiment, and the above detection and distance information calculation are performed by the photoelectric conversion device 403. The distance image formation is performed by the image processing circuit 404 based on the obtained distance signal. The formed distance image is supplied to the monitor 405 to be displayed, or to the memory 406 to be stored.

[0252] (Experimental Example)

[0253] FIG. 30A-FIG. 30C An experimental example of the fifteenth embodiment is shown.

[0254] FIG. 30A is a graph showing the setting of the experiment. Pulse laser light is emitted from a laser 320 of 510 nm at 40 MHz. The object 350 is irradiated with the pulse laser light diffused by a light diffusion member 330. The SPAD camera 310 and the laser 320 are configured to be synchronized with each other by a pulse generator 325. A transparent plate 340 made of plastic is provided between the SPAD camera 310 and the object 350.

[0255] FIG. 30B and FIG. 30CThe relationship between the position of the gate window (gate position) and the detected count value is shown in the pixels corresponding to the specific position of the object 350. FIG. 30B is a curve in the case where the transparent plate 340 is not provided, FIG. 30C is a curve in the case where the transparent plate 340 is provided. FIG. 30C The curve of has a two-stage rise (position 40 and position 100). The curve having such a two-stage rise corresponds to a double reflection from the transparent plate 340 and the object 350. From FIG. 30A-FIG. 30C The reflected light distribution is obtained from the measurement curve, and the distance information is obtained from the reflected light distribution. The distance information and the light intensity distribution information are obtained in each pixel arranged in two dimensions, and when the light intensity distribution information is displayed in monochrome and the distance information is displayed in color, three-dimensional imaging can be performed.

[0256] In addition, when the distance information is obtained, three-dimensional imaging of a specified distance range can be performed. For example, signals closer to the SPAD camera and signals farther from the SPAD are separated from each other, so that separate three-dimensional imaging images can be formed.

[0257] For example, in the case where the transparent plate is a window glass of a vehicle and it is desired to observe only the object behind the window glass, when distance image formation of both the window glass and the object is performed using a commonly used indirect ToF method or the like, an error can occur in distance measurement due to the influence of reflection from the window glass. In this case, as described according to the twelfth embodiment, in the case where a movable object (for example, a car) is controlled by distance measurement, unintended control can be performed, and a problem can occur in terms of safety. According to the present embodiment, since three-dimensional imaging of objects different in distance from the camera can be performed separately, such a concern can be reduced.

[0258] <Sixteenth Embodiment>

[0259] A light-receiving device according to the sixteenth embodiment will be described. FIG. 31A-FIG. 31B A light-receiving device according to the sixteenth embodiment will be described.

[0260] FIG. 31A is a circuit diagram of a pixel. Specifically, FIG. 31A The light-receiving device according to the sixteenth embodiment is shown. FIG. 2 The light-receiving device according to the sixteenth embodiment is shown. Q The avalanche current generated in the avalanche diode is converted into a voltage. The voltage pulse is transmitted to the pull-down transistor M G via the gate transistor M PD As a result, the feedback transistor M FB enters an off state. In this way, the quenching transistor M Qof the source of the pull-down transistor M PD of the drain is maintained for a sufficiently long period of time to approach a ground voltage (ground voltage) until the signal on the entire chip is read. For the next light detection, the potential charged to VDDH-VTH-VDSAT. Thereafter, the feedback transistor M FB is returned to the on state from the off state. The transistor M SW connected to the drain of the pull-down transistor M PD of the source of the transistor M RS and the source of the transistor M RS is precharged to VDD-VTH by the control signal VRES. When the transistor M SEL is brought to the on state by VSEL, the transistor M PDO is used for the entire column pull-down. For example, the row is selected in the order of the row.

[0261] Here, as shown by the dashed lines, the transistor M RS , the transistor M PDO and the transistor M SEL are shared by a plurality of pixels (a plurality of avalanche diodes). Specifically, these transistors are shared by four pixels (four avalanche diodes) of two rows and two columns. Since a plurality of pixels share the same circuit, more avalanche diodes can be arranged in the same area. According to the above-described embodiment, as shown in FIG. 5A-FIG. 5C , when the potential barrier formed by the first isolation portion 20 is set to be lower than the potential barrier formed by the second isolation portion 30, the pixel size is reduced while the crosstalk is reduced. In addition to this, by using the pixel circuit of the present embodiment, since the pixel size can be further reduced at the time of array, it is possible to provide a SPAD array sensor having more pixels.

[0262] The pixel of the present embodiment has a feedback loop that can prevent the occurrence of a subsequent avalanche in a frame. The feedback loop can suppress the current from the cathode voltage node VOP. Since the case of exceeding 100,000 counts can affect power consumption, it can be said that this is advantageous in a large-area array.

[0263] FIG. 31B is a diagram showing a driving method. When VQR and VG are transitioned from the H level to the L level, exposure is started, and when VQR and VG are transitioned from the L level to the H level, exposure of one subframe is performed. At this time, the exposure period of the subframe is basically defined as the period from the timing at which VQR is transitioned from the H level to the L level to the timing at which VG is transitioned from the H level to the L level. When the subframe period is repeated a plurality of times, a sufficient photon count value can be obtained even for a weak light signal. During the read period, VRES is first set to the H level to reset M RSsource terminal. Next, VSW is set to an H level to write the output signal into M RS source terminal. The case where a photon is detected during the exposure period corresponds to an L level, and the case where no photon is detected corresponds to an H level. Further, VSEL is set to an H level to output the pixel signal to the vertical signal line. After the read is completed, all of VRES, VSW, VQR, and VG are set to H levels at the same time to perform a reset.

[0264] <Seventeenth Embodiment>

[0265] will be described. FIG. 32 and FIG. 33A to FIG. 35B A filter corresponding to the seventeenth embodiment will be described. FIG. 32 is a graph showing spectral transmittance of each filter, FIG. 33A to FIG. 35B shows a specific arrangement example of the filter in the photoelectric conversion device of the present embodiment.

[0266] Such a filter for transmitting light of a specific wavelength component to an avalanche photodiode arranged on a substrate can be provided in the photoelectric conversion device. The filter is, for example, a color filter (may also be denoted as CF), an infrared light filter, an infrared light cut filter, or the like. These filters can be used individually or in combination.

[0267] The CF is, for example, a filter for transmitting visible light such as red, green, or blue. Hereinafter, red, green, and blue are denoted as R, G, and B. In addition, a pixel in which a CF of R is arranged is denoted as an R pixel, a pixel in which a CF of G is arranged is denoted as a G pixel, and a pixel in which a CF of B is arranged is denoted as a B pixel. Further, in the case of collectively denoting the R pixel, the G pixel, and the B pixel, they can be denoted as an RGB pixel. Further, hereinafter, infrared light is denoted as IR. A pixel on which a filter for transmitting IR is arranged is denoted as an IR pixel.

[0268] FIG. 32 shows spectral transmittance of the filter. FIG. 32 is a graph in which the horizontal axis shows wavelength (unit: nm) and the vertical axis shows spectral transmittance (unit: %). First, the wavelength range of visible light is generally in the range of 400 nm or more and less than 700 nm, and the wavelength range of infrared light is 750 nm or more and 1 mm or less. Here, the spectral transmittance of the IR filter is 50% or more in the wavelength range of at least 700 nm or more, and less than 50% in the wavelength range of less than 700 nm. That is, the IR filter refers to a filter that mainly transmits infrared light, and cuts visible light. As shown in FIG. 32The spectral transmittance of the IR filter indicates a value of 90% or more around 740 nm, but is not more than 50% at 700 nm or less, as indicated by the solid line IR in FIG. 1. On the other hand, the spectral transmittance of the visible light filter is 50% or more in the wavelength range of less than 700 nm. That is, the visible light filter refers to a filter that mainly transmits visible light. The visible light filter can transmit light in the visible light wavelength range below the infrared light wavelength as long as it transmits light in the visible light wavelength range below the infrared light wavelength (for example, transmits light with a wavelength of less than 700 nm). As FIG. 32 The spectral transmittance of each of the visible light filters exceeds 50% in a specific wavelength of less than 700 nm, as indicated by the solid lines R, G, and B in FIG. 1. For example, the peak of the spectral transmittance of the R filter is at about 650 nm, the peak of the spectral transmittance of the G filter is at about 550 nm, and the peak of the spectral transmittance of the B filter is at about 450 nm. The visible light filter can partially transmit light in the infrared light wavelength range, but in order to remove the influence of infrared light, the visible light filter can be designed not to transmit light in the infrared light wavelength range, for example, light with a wavelength of 700 nm or more. That is, the visible light filter can have a function as a so-called IR cut filter. Furthermore, the visible light filter can include an infrared light cut filter that cuts light with a wavelength of 700 nm or more, for example. FIG. 32 The range of light transmitted by the IR cut filter is exemplified. The material of each filter can be an organic material or can be an inorganic material. Note that the non-light-transmitting or non-transparent is not limited to a state of 100% non-light-transmission. For example, such a state refers to a state of transmitting light by 50% or more.

[0269] FIG. 33A An example of an arrangement of the CFs is described, which has a so-called Bayer array. The CF ratio of R:G:B is 1:2:1.

[0270] FIG. 33B An example of an arrangement of the CFs of RGBW12 is shown. According to this array, each CF is arranged in a 4x4 pixel array at a ratio of R:G:B:W=1:2:1:12. W refers to a white pixel that is a pixel in which no CF is arranged. The W pixel is arranged to be adjacent to any of the R pixel, the G pixel, and the B pixel corresponding to the color pixel in each of the up-down direction, the left-right direction, and the oblique direction in a plan view. That is, each of the R pixel, the G pixel, and the B pixel is surrounded by 8 W pixels. The W pixel occupies 3 / 4 of all the pixels. The periphery of each of the RGB pixels corresponding to the color pixel is surrounded by the W pixel, and the interpolation accuracy of the signal for interpolating the W pixel is improved for each of the signals of the R pixel, the G pixel, and the B pixel.

[0271] FIG. 34 is an example of an arrangement of the W pixel using the IR pixel instead of FIG. 33B the W pixel of FIG. 1. Such a filter arrangement can be used.

[0272] Further, as shown in FIG. 35A-FIG. 35B each pixel can be arranged in a honeycomb shape. In FIG. 35A-FIG. 35B IR pixels are arranged, but W pixels can be used instead of IR pixels.

[0273] In this way, the photoelectric conversion device according to the present embodiment can employ various filter arrangements.

[0274] The present application can be variously modified without being limited to the above-described embodiments. For example, examples in which a part of the configuration of any of the embodiments is added to other embodiments and examples in which a replacement with a part of the configuration of other embodiments is performed are also embodiments of the present application.

[0275] Note that the above-described embodiments are merely examples of embodiments of the present application, and the technical scope of the present application is not to be interpreted in a limited manner by these embodiments. That is, the present application can be implemented in various forms without departing from the technical concept thereof or the main features thereof.

[0276] For example, an example of arranging filters is shown according to the seventeenth embodiment, but the photoelectric conversion device of each embodiment can be used as a photoelectric conversion device that photoelectrically converts monochromatic light without arranging a CF or IR cut filter or a visible light cut filter.

[0277] This application claims priority from Japanese Patent Application No. 2020-015607 filed on January 31, 2020, Japanese Patent Application No. 2020-108754 filed on June 24, 2020, and Japanese Patent Application No. 2020-183448 filed on November 2, 2020, the entire contents of which are incorporated herein by reference.

Claims

1. An optical-to-electrical conversion device, comprising: a first avalanche diode including a first semiconductor region of a first conductivity type in which majority carriers are charge carriers of the same conductivity type as signal charges; and a second avalanche diode including a second semiconductor region of the first conductivity type and arranged adjacent to the first avalanche diode, wherein a first isolation portion is arranged between the first semiconductor region and the second semiconductor region, the first isolation portion is constituted by a third semiconductor region of the first conductivity type, a seventh semiconductor region of a second conductivity type is arranged at a position overlapping the third semiconductor region in a plan view and deeper than the third semiconductor region, the second conductivity type being a conductivity type different from the first conductivity type, the third semiconductor region and the seventh semiconductor region constitute a P-N junction, and an impurity concentration of the third semiconductor region is lower than an impurity concentration of the seventh semiconductor region, the seventh semiconductor region is arranged in a first portion of a periphery of the first semiconductor region, and is not arranged in a second portion of the periphery of the first semiconductor region different from the first portion, wherein no semiconductor region of the second conductivity type is arranged between the first semiconductor region and the second semiconductor region.

2. The photoelectric conversion device according to claim 1, wherein the third semiconductor region is in contact with the first semiconductor region and the second semiconductor region.

3. The optical-to-electrical conversion device according to claim 1, further comprising: a third avalanche diode arranged adjacent to the second avalanche diode and including an eighth semiconductor region of the first conductivity type, wherein in a plan view, the first avalanche diode and the second avalanche diode are aligned in a first direction, and the second avalanche diode and the third avalanche diode are aligned in a second direction intersecting the first direction, and in the plan view, a contact plug that supplies a potential to one node of the first avalanche diode is arranged between the first semiconductor region and the eighth semiconductor region.

4. The optical-to-electrical conversion device according to claim 1, wherein the first semiconductor region and the second semiconductor region are arranged on a substrate, a memory or a counter circuit configured to detect an avalanche current generated based on a signal from the first avalanche diode is arranged on a second substrate different from the substrate, and the substrate and the second substrate are laminated.

5. The photoelectric conversion device according to claim 1, wherein trench isolation is applied between the first semiconductor region and the second semiconductor region.

6. The optical-to-electrical conversion device according to claim 1, wherein the first avalanche diode and the second avalanche diode operate in a Geiger mode.

7. The optical-to-electrical conversion device according to claim 1, further comprising: a color filter, wherein light transmitted through the color filter is incident on the first avalanche diode and the second avalanche diode.

8. An optical-to-electrical conversion device, comprising: a first avalanche diode including a first semiconductor region of a first conductivity type in which majority carriers are charge carriers of the same conductivity type as signal charges; and a second avalanche diode including a second semiconductor region of the first conductivity type and arranged adjacent to the first avalanche diode, wherein a first isolation portion is arranged between the first semiconductor region and the second semiconductor region, the first isolation portion is composed of a fourth semiconductor region of a second conductivity type and a third semiconductor region of the first conductivity type, the second conductivity type being a conductivity type different from the first conductivity type, the third semiconductor region being arranged to sandwich the fourth semiconductor region in a plan view, and the impurity concentration Nd of the third semiconductor region, the impurity concentration Na of the fourth semiconductor region, the elementary charge q, the dielectric constant of the semiconductor the potential difference V between the third semiconductor region and the P-N junction of the fourth semiconductor region, and the length D of the fourth semiconductor region sandwiched by the third semiconductor region satisfy Expression 1, [Expression 1] 。 9. The photoelectric conversion device according to claim 8, wherein the third semiconductor region is in contact with the first semiconductor region and the second semiconductor region.

10. The photoelectric conversion device according to claim 8, further comprising: a third avalanche diode arranged adjacent to the second avalanche diode and including an eighth semiconductor region of the first conductivity type, wherein in a plan view, the first avalanche diode and the second avalanche diode are aligned in a first direction, and the second avalanche diode and the third avalanche diode are aligned in a second direction intersecting the first direction, and in a plan view, a contact plug that supplies a potential to one node of the first avalanche diode is arranged between the first semiconductor region and the eighth semiconductor region.

11. The photoelectric conversion device according to claim 8, wherein the first semiconductor region and the second semiconductor region are arranged on a substrate, a memory or a counter circuit configured to detect an avalanche current generated based on a signal from the first avalanche diode is arranged on a second substrate different from the substrate, and the substrate and the second substrate are laminated.

12. The photoelectric conversion device according to claim 8, wherein A trench isolation is applied between the first semiconductor region and the second semiconductor region.

13. The photoelectric conversion device according to claim 8, wherein the first avalanche diode and the second avalanche diode operate in a Geiger mode.

14. The photoelectric conversion device according to claim 8, further comprising: a color filter, wherein light transmitted through the color filter is incident on the first avalanche diode and the second avalanche diode.

15. A photoelectric conversion device comprising: a substrate having a first face and a second face opposite to the first face; a first avalanche diode including a first semiconductor region of a first conductivity type arranged at a first depth of the substrate, a majority of charge carriers being of the same conductivity type as a signal charge, and a fifth semiconductor region of a second conductivity type arranged at a second depth between the first depth and the second face and arranged between the first semiconductor region and the second face, the second conductivity type being a conductivity type different from the first conductivity type; and a second avalanche diode including a second semiconductor region of the first conductivity type arranged at the first depth of the substrate and a sixth semiconductor region of the second conductivity type arranged at the second depth and arranged between the second semiconductor region and the second face, the second avalanche diode being arranged adjacent to the first avalanche diode, wherein a first isolation portion is arranged at the first depth between the first semiconductor region and the second semiconductor region, at least one of an intrinsic semiconductor region, a third semiconductor region of the first conductivity type, and a fourth semiconductor region of the second conductivity type is arranged in the first isolation portion, a seventh semiconductor region of the second conductivity type is arranged at the second depth between the fifth semiconductor region and the sixth semiconductor region, and on a line passing through the first isolation portion and the seventh semiconductor region and perpendicular to the first face, a potential height with respect to the signal charge decreases from the seventh semiconductor region toward the first isolation portion, and a difference between the potential height in the first semiconductor region with respect to the signal charge and the potential height in the fifth semiconductor region with respect to the signal charge is greater than a difference between the potential height in the first isolation portion with respect to the signal charge and the potential height in the seventh semiconductor region with respect to the signal charge.

16. The photoelectric conversion device according to claim 15, wherein the first isolation portion includes the third semiconductor region.

17. The photoelectric conversion device according to claim 16, wherein the third semiconductor region is shared by the first avalanche diode and the second avalanche diode.

18. The photoelectric conversion device according to claim 17, wherein an impurity concentration of the third semiconductor region is lower than an impurity concentration of the first semiconductor region.

19. The photoelectric conversion device according to claim 15, further comprising: a third avalanche diode arranged adjacent to the second avalanche diode and including an eighth semiconductor region of the first conductivity type, wherein in a plan view, the first avalanche diode and the second avalanche diode are aligned in a first direction, and the second avalanche diode and the third avalanche diode are aligned in a second direction intersecting the first direction, and in a plan view, a contact plug that supplies a potential to one node of the first avalanche diode is arranged between the first semiconductor region and the eighth semiconductor region.

20. The photoelectric conversion device according to claim 19, wherein a ninth semiconductor region of the second conductivity type is arranged between the first semiconductor region and the eighth semiconductor region, a fourth semiconductor region is arranged between the first semiconductor region and the second semiconductor region, the contact plug is connected to the ninth semiconductor region, and an impurity concentration of the fourth semiconductor region is lower than an impurity concentration of the ninth semiconductor region.

21. The photoelectric conversion device according to claim 19 or 20, wherein the contact plug is formed on a first face of a substrate, and light is incident from a second face side of the substrate opposite the first face.

22. The photoelectric conversion device according to claim 19 or 20, wherein A first distance between the first semiconductor region and the second semiconductor region is shorter than a second distance between the first semiconductor region and the eighth semiconductor region.

23. The photoelectric conversion device according to claim 22, wherein The first distance is 1 / 8 or more of the second distance.

24. The photoelectric conversion device according to claim 15, wherein The first semiconductor region and the second semiconductor region are arranged on a substrate, A memory or a counter circuit configured to detect an avalanche current generated based on a signal from the first avalanche diode is arranged on a second substrate different from the substrate, and The substrate and the second substrate are stacked.

25. The photoelectric conversion device according to claim 15, wherein A trench isolation is applied between the first semiconductor region and the second semiconductor region.

26. The photoelectric conversion device according to claim 25, wherein One end of the trench isolation is formed to a position deeper than the first semiconductor region with respect to a first surface.

27. The photoelectric conversion device according to claim 15, wherein The first avalanche diode and the second avalanche diode operate in a Geiger mode.

28. The photoelectric conversion device according to claim 15, further comprising: a color filter, wherein Light transmitted through the color filter is incident on the first avalanche diode and the second avalanche diode.

29. The photoelectric conversion device according to claim 19, further comprising: at least one of a memory, a time-to-digital conversion circuit, and a counter arranged corresponding to the first avalanche diode and configured to detect an avalanche current generated by avalanche multiplication in the first avalanche diode, wherein In a plan view, a contact plug that supplies a potential to one node of the first avalanche diode is arranged between the first semiconductor region included in the first avalanche diode and the eighth semiconductor region included in the third avalanche diode, In a plan view, the contact plug that supplies the potential to the one node is not arranged between the first semiconductor region included in the first avalanche diode and the second semiconductor region included in the second avalanche diode, The contact plug is connected to a semiconductor region of the second conductivity type arranged between the first semiconductor region included in the first avalanche diode and the eighth semiconductor region included in the third avalanche diode, and The contact plug and the semiconductor region of the second conductivity type are shared by the first avalanche diode, the second avalanche diode, and the third avalanche diode.

30. The photoelectric conversion device according to claim 29, further comprising: a second contact plug that supplies a potential to the first semiconductor region of the first avalanche diode, wherein a distance between the second contact plug that supplies the potential to the first semiconductor region of the first avalanche diode and the contact plug, a distance between a third contact plug that supplies a potential to the second semiconductor region of the second avalanche diode and the contact plug, and a distance between a fourth contact plug that supplies a potential to the eighth semiconductor region of the third avalanche diode and the contact plug are equal to each other.

31. The photoelectric conversion device according to claim 29 or 30, wherein The contact plug is formed on a first surface of a substrate, and light is incident from a second surface side of the substrate opposite the first surface.

32. A photoelectric conversion system including: The photoelectric conversion device according to any one of claims 1 to 31; and a signal processing unit configured to process a signal output by the photoelectric conversion device.

33. A movable object including: The photoelectric conversion device according to any one of claims 1 to 31; and distance information obtaining means configured to obtain distance information about a distance to an object from ranging information based on a signal from the photoelectric conversion device, wherein the movable object further includes control means configured to control the movable object based on the distance information.

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