Photoelectric conversion device, and photoelectric conversion system

Abstract

To achieve both noise reduction and pixel integration.SOLUTION: A photoelectric conversion device has a first substrate that has a first semiconductor layer having a first surface and a second surface, and a first wiring structure arranged on the first semiconductor layer, and includes an avalanche photodiode provided on the first semiconductor layer, and a resistance element connected with the avalanche photodiode. The first wiring structure has wiring that supplies first voltage to the avalanche photodiode. The distance between the resistance element and the first surface of the first semiconductor layer is longer than the distance between the wiring and the first surface of the first semiconductor layer.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a photoelectric conversion device, a photoelectric conversion system using the photoelectric conversion device, and the driving of the photoelectric conversion system. [Background technology]

[0002] As a means for operating a photoelectric conversion device using an avalanche photodiode (APD) in Geiger mode, a method is known in which a thin-wire resistor (quench element) made of a material such as polysilicon is disposed on the surface of a semiconductor layer on which the APD is provided. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-226073 A Summary of the Invention [Problem to be solved by the invention]

[0004] The configuration described in Patent Document 1 has a problem that, particularly when using fine pixels, the potential of the quenching element arranged near the APD and its fluctuation affect the electrostatic potential of the APD, causing an increase in noise. The present invention has been made in view of the above problem, and aims to achieve both noise suppression and pixel integration. [Means for solving the problem]

[0005] One aspect of the present invention is a photoelectric conversion device having a first substrate including a first semiconductor layer having a first surface and a second surface, and a first wiring structure arranged on the first semiconductor layer, the device including an avalanche photodiode provided in the first semiconductor layer, and a resistive element connected to the avalanche photodiode, the first wiring structure having wiring for supplying a first voltage to the avalanche photodiode, and the distance between the resistive element and the first surface of the first semiconductor layer being longer than the distance between the wiring and the first surface of the first semiconductor layer. Effect of the Invention

[0006] According to the present invention, it is possible to achieve both noise suppression and pixel integration in a photoelectric conversion device. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic diagram of a photoelectric conversion device according to an embodiment. [Diagram 2] 3 is a schematic diagram of a sensor substrate of the photoelectric conversion device according to the embodiment. FIG. [Diagram 3] 2 is a schematic diagram of a circuit board of a photoelectric conversion device according to an embodiment. FIG. [Figure 4] 2 is a configuration example of a pixel circuit of a photoelectric conversion device according to an embodiment. [Diagram 5] 3 is a schematic diagram showing driving of a pixel circuit of a photoelectric conversion device according to an embodiment. FIG. [Figure 6] 1 is a cross-sectional view of a pixel portion of a photoelectric conversion device according to a first embodiment. [Figure 7] FIG. 2 is a plan view of a pixel unit of the photoelectric conversion device according to the first embodiment. [Figure 8] 13 is a configuration example of a pixel circuit of a photoelectric conversion device according to a second embodiment. [Figure 9] FIG. 4 is a cross-sectional view of a pixel portion of a photoelectric conversion device according to a second embodiment. [Figure 10] FIG. 11 is a plan view of a pixel unit of a photoelectric conversion device according to a second embodiment. [Figure 11]FIG. 11 is a cross-sectional view of a photoelectric conversion device according to a modified example of the second embodiment. [Figure 12] 13 is a configuration example of a pixel circuit of a photoelectric conversion device according to a third embodiment. [Figure 13] FIG. 11 is a cross-sectional view of a pixel portion of a photoelectric conversion device according to a third embodiment. [Figure 14] FIG. 11 is a plan view of a pixel unit of a photoelectric conversion device according to a third embodiment. [Figure 15] FIG. 13 is a functional block diagram of a photoelectric conversion system according to a fourth embodiment. [Figure 16] FIG. 13 is a functional block diagram of a photoelectric conversion system according to a fifth embodiment. [Figure 17] FIG. 13 is a functional block diagram of a photoelectric conversion system according to a sixth embodiment. [Figure 18] FIG. 13 is a functional block diagram of a photoelectric conversion system according to a seventh embodiment. [Figure 19] FIG. 13 is a functional block diagram of a photoelectric conversion system according to an eighth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The following embodiments are intended to embody the technical ideas of the present invention, and are not intended to limit the present invention. The sizes and positional relationships of the components shown in the drawings may be exaggerated to clarify the description. In the following description, the same components may be designated by the same reference numerals, and the description may be omitted.

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, terms indicating specific directions or positions (for example, "upper", "lower", "right", "left" and other terms including these terms) will be used as necessary. The use of these terms is for the purpose of facilitating understanding of the embodiment with reference to the drawings, and the technical scope of the present invention is not limited by the meaning of these terms.

[0010] In this specification, the plan view refers to a view from a direction perpendicular to the light incident surface of the semiconductor layer. Also, the cross-sectional view refers to a surface in a direction perpendicular to the light incident surface of the semiconductor layer. Note that, when the light incident surface of the semiconductor layer is a rough surface when viewed microscopically, the plan view is defined based on the light incident surface of the semiconductor layer when viewed macroscopically.

[0011] In the following description, the anode of the APD is set to a fixed potential, and a signal is taken out from the cathode side. Therefore, the first conductive type semiconductor region having charges of the same polarity as the signal charge as the majority carrier is an N-type semiconductor region, and the second conductive type semiconductor region having charges of a different polarity than the signal charge as the majority carrier is a P-type semiconductor region. The present invention is also valid when the cathode of the APD is set to a fixed potential, and a signal is taken out from the anode side. In this case, the first conductive type semiconductor region having charges of the same polarity as the signal charge as the majority carrier is a P-type semiconductor region, and the second conductive type semiconductor region having charges of a different polarity than the signal charge as the majority carrier is an N-type semiconductor region. In the following, a case where one node of the APD is set to a fixed potential will be described, but the potentials of both nodes may fluctuate.

[0012] In this specification, when the term "impurity concentration" is used simply, it means the net impurity concentration minus the amount compensated by the impurity of the opposite conductivity type. In other words, "impurity concentration" refers to the NET doping concentration. A region where the P-type doped impurity concentration is higher than the N-type doped impurity concentration is a P-type semiconductor region. Conversely, a region where the N-type doped impurity concentration is higher than the P-type doped impurity concentration is an N-type semiconductor region.

[0013] A configuration common to each embodiment of a photoelectric conversion device and a driving method thereof that can be used with a processing device according to the present invention will be described with reference to Figures 1 to 5. Note that although a processing device provided outside the photoelectric conversion device will be described in this description, the processing device may be configured, for example, within the photoelectric conversion device.

[0014] FIG. 1 is a diagram showing the configuration of a stacked photoelectric conversion device 100 according to an embodiment of the present invention. The photoelectric conversion device 100 is configured by stacking and electrically connecting two substrates, a sensor substrate 11 as a first substrate and a circuit substrate 21 as a second substrate. The sensor substrate 11 has a first semiconductor layer having a photoelectric conversion element 102 described later, and a first wiring structure. The circuit substrate 21 has a second semiconductor layer having circuits such as a signal processing portion 103 described later, and a second wiring structure. The photoelectric conversion device 100 is configured by stacking the second semiconductor layer, the second wiring structure, the first wiring structure, and the first semiconductor layer in this order. The photoelectric conversion device described in each embodiment is a back-illuminated photoelectric conversion device in which light is incident from the first surface and a circuit substrate is disposed on the second surface.

[0015] In the following, the sensor substrate 11 and the circuit substrate 21 are described as diced chips, but are not limited to chips. For example, each substrate may be a wafer. Also, each substrate may be stacked in a wafer state and then diced, or may be chipped and then stacked and bonded.

[0016] A pixel region 12 is disposed on the sensor substrate 11, and a circuit region 22 that processes signals detected in the pixel region 12 is disposed on the circuit substrate 21.

[0017] 2 is a diagram showing an example of the arrangement of the sensor substrate 11. Pixels 101, each having a photoelectric conversion element 102 including an APD, are arranged in a two-dimensional array in a plan view to form a pixel region 12.

[0018] The pixel 101 is typically a pixel for generating an image, but when used for TOF (Time of Flight), it does not necessarily have to generate an image. In other words, the pixel 101 may be a pixel for measuring the time when light arrives and the amount of light.

[0019] 3 is a configuration diagram of the circuit board 21. It has a signal processing unit 103 that processes electric charges photoelectrically converted by the photoelectric conversion element 102 in FIG. 2, a readout circuit 112, a control pulse generating unit 115, a horizontal scanning circuit unit 111, a signal line 113, and a vertical scanning circuit unit 110.

[0020] The photoelectric conversion element 102 in FIG. 2 and the signal processing unit 103 in FIG. 3 are electrically connected via connection wiring provided for each pixel.

[0021] The vertical scanning circuit section 110 receives a control pulse supplied from a control pulse generating section 115 and supplies the control pulse to each pixel. The vertical scanning circuit section 110 uses logic circuits such as a shift register and an address decoder.

[0022] The signal output from the photoelectric conversion element 102 of the pixel is processed by a signal processing unit 103. The signal processing unit 103 is provided with a counter, a memory, etc., and digital values ​​are held in the memory.

[0023] The horizontal scanning circuit unit 111 inputs a control pulse for sequentially selecting each column to the signal processing unit 103 in order to read out the signal from the memory of each pixel in which the digital signal is held.

[0024] A signal is output to the signal line 113 from the signal processing unit 103 of the pixel selected by the vertical scanning circuit unit 110 for the selected column.

[0025] The signal output to the signal line 113 is output via an output circuit 114 to a recording unit or a signal processing unit outside the photoelectric conversion device 100 .

[0026] 2, the photoelectric conversion elements in the pixel region may be arranged one-dimensionally. The function of the signal processing unit does not necessarily need to be provided for each of the photoelectric conversion elements, and for example, one signal processing unit may be shared by a plurality of photoelectric conversion elements to perform signal processing sequentially.

[0027] 2 and 3, a plurality of signal processing units 103 are arranged in a region overlapping the pixel region 12 in a planar view. A vertical scanning circuit unit 110, a horizontal scanning circuit unit 111, a column circuit 112, an output circuit 114, and a control pulse generating unit 115 are arranged so as to overlap between an end of the sensor substrate 11 and an end of the pixel region 12 in a planar view. In other words, the sensor substrate 11 has the pixel region 12 and a non-pixel region arranged around the pixel region 12, and the vertical scanning circuit unit 110, the horizontal scanning circuit unit 111, the column circuit 112, the output circuit 114, and the control pulse generating unit 115 are arranged in a region overlapping the non-pixel region in a planar view.

[0028] FIG. 4 is an example of a block diagram including the equivalent circuits of FIG. 2 and FIG.

[0029] In FIG. 2, a photoelectric conversion element 102 having an APD 201 is provided on a sensor substrate 11, and other members are provided on a circuit substrate 21.

[0030] The APD201 is a photoelectric conversion unit that generates charge pairs according to incident light by photoelectric conversion. A voltage VL (first voltage) is supplied to the anode of the APD201. A voltage VH (second voltage) higher than the voltage VL supplied to the anode is supplied to the cathode of the APD201. A reverse bias voltage that causes the APD201 to perform avalanche multiplication is supplied to the anode and cathode. By supplying such a voltage, the charge generated by the incident light undergoes avalanche multiplication, generating an avalanche current. Two power supply wiring systems that supply voltages to the cathode and anode of the APD201 are arranged on the first substrate.

[0031] When a reverse bias voltage is supplied, there are two modes: Geiger mode, in which the potential difference between the anode and cathode is greater than the breakdown voltage, and linear mode, in which the potential difference between the anode and cathode is close to or less than the breakdown voltage.

[0032] An APD operated in Geiger mode is called a SPAD. For example, the voltage VL (first voltage) is −30 V, and the voltage VH (second voltage) is 1 V. The APD 201 may be operated in either linear mode or Geiger mode. A SPAD is preferable because the potential difference is larger than that of a linear mode APD, resulting in a significant improvement in the signal-to-noise ratio.

[0033] The resistive element 202 is connected between a power supply that supplies a voltage VH and the APD 201. The resistive element 202 functions as a load circuit (quench circuit) during signal multiplication by avalanche multiplication, and has a function of suppressing avalanche multiplication by suppressing the voltage supplied to the APD 201 (quench operation). The resistive element 202 also has a function of returning the voltage supplied to the APD 201 to the voltage VH by flowing a current equivalent to the voltage drop caused by the quench operation (recharge operation).

[0034] The signal processing unit 103 has a waveform shaping unit 210 and a counter circuit 211. In this specification, it is sufficient that the signal processing unit 103 has either the waveform shaping unit 210 or the counter circuit 211.

[0035] The waveform shaping unit 210 shapes the potential change of the cathode of the APD 201 obtained at the time of photon detection, and outputs a pulse signal. For example, an inverter circuit is used as the waveform shaping unit 210, but a circuit in which multiple inverters are connected in series may also be used, or other circuits having a waveform shaping effect may also be used.

[0036] The counter circuit 211 counts the pulse signal output from the waveform shaping section 210 and holds the count value.

[0037] The electrical connection may be switched by disposing a switch such as a transistor between the resistive element 202 and the APD 201 or between the photoelectric conversion element 102 and the signal processing unit 103. Similarly, the supply of the voltage VH or the voltage VL to the photoelectric conversion element 102 may be electrically switched using a switch such as a transistor.

[0038] In this embodiment, a configuration using the counter circuit 211 has been shown. However, instead of the counter circuit 211, a photoelectric conversion device 100 may be configured to acquire the pulse detection timing using a time-to-digital converter (hereinafter, TDC) and a memory. In this case, the generation timing of the pulse signal output from the waveform shaping unit 210 is converted into a digital signal by the TDC. To measure the timing of the pulse signal, a control pulse pREF (reference signal) is supplied to the TDC from the vertical scanning circuit unit 110 in FIG. 1 via a drive line. The TDC acquires, as a digital signal, a signal obtained by converting the input timing of the signal output from each pixel via the waveform shaping unit 210 into a relative time based on the control pulse pREF.

[0039] FIG. 5 is a diagram showing a schematic diagram of the relationship between the operation of an APD and an output signal.

[0040] Fig. 5(a) is a diagram excerpting the APD 201, resistive element 202, and waveform shaping unit 210 of Fig. 4. Here, the input side of the waveform shaping unit 210 is node A, and the output side is node B. Fig. 5(b) shows the waveform change of node A in Fig. 5(a), and Fig. 5(c) shows the waveform change of node B in Fig. 5(a).

[0041] Between time t0 and time t1, a potential difference of VH-VL is applied to the APD 201 in FIG. 5(a). When a photon is incident on the APD 201 at time t1, avalanche multiplication occurs in the APD 201, an avalanche multiplication current flows through the resistive element 202, and the voltage at nodeA drops. When the voltage drop amount becomes larger and the potential difference applied to the APD 201 becomes smaller, the avalanche multiplication of the APD 201 stops as at time t2, and the voltage level at nodeA does not drop by more than a certain value. After that, between time t2 and time t3, a current that compensates for the voltage drop from the voltage VL flows through nodeA, and at time t3, nodeA is stabilized to the original potential level. At this time, the part of the output waveform at nodeA that exceeds a certain threshold is shaped by the waveform shaping unit 210 and output as a signal at nodeB.

[0042] The arrangement of the signal lines 113, the column circuits 112, and the output circuits 114 is not limited to that shown in Fig. 3. For example, the signal lines 113 may be arranged to extend in the row direction, and the column circuits 112 may be arranged at the ends of the signal lines 113.

[0043] The photoelectric conversion devices of the respective embodiments will be described below.

[0044] (First embodiment) The photoelectric conversion device according to the first embodiment will be described with reference to FIGS.

[0045] FIG. 6 is a cross-sectional view of two pixels of the photoelectric conversion element 102 of the photoelectric conversion device according to the first embodiment, taken in a direction perpendicular to the surface direction of the substrate, and corresponds to the AA' cross section in FIG. 7(a).

[0046] The following describes the structure and function of the photoelectric conversion element 102. The photoelectric conversion element 102 has a first semiconductor region 311 of N type, a third semiconductor region 313, a fifth semiconductor region 315, and a sixth semiconductor region 316. It further includes a second semiconductor region 312, a fourth semiconductor region 314, a seventh semiconductor region 317, and a ninth semiconductor region 319 of P type.

[0047] 6, an N-type first semiconductor region 311 is formed in the vicinity of the surface facing the light incident surface, and an N-type third semiconductor region 313 is formed around it. A P-type second semiconductor region 312 is formed at a position overlapping the first semiconductor region and the second semiconductor region in a planar view. An N-type fifth semiconductor region 315 is further disposed at a position overlapping the second semiconductor region 312 in a planar view, and an N-type sixth semiconductor region 316 is formed around it.

[0048] The first semiconductor region 311 has a higher N-type impurity concentration than the third semiconductor region 313 and the fifth semiconductor region 315. A PN junction is formed between the P-type second semiconductor region 312 and the N-type first semiconductor region 311. By making the impurity concentration of the second semiconductor region 312 lower than that of the first semiconductor region 311, all regions of the second semiconductor region 312 that overlap the center of the first semiconductor region in a planar view become depletion layer regions. At this time, the potential difference between the first semiconductor region 311 and the second semiconductor region 312 becomes larger than the potential difference between the second semiconductor region 312 and the fifth semiconductor region 315. Furthermore, this depletion layer region extends to a partial region of the first semiconductor region 311, and a strong electric field is induced in the extended depletion layer region. This strong electric field causes avalanche multiplication in the depletion layer region that extends to a partial region of the first semiconductor region 311, and a current based on the amplified charge is output as a signal charge. When light incident on the photoelectric conversion element 102 is photoelectrically converted and avalanche multiplication occurs in the depletion layer region (avalanche multiplication region), the generated charges of the first conductivity type are collected in the first semiconductor region 311 .

[0049] 6, the third semiconductor region 313 and the fifth semiconductor region 315 are formed to have approximately the same size, but the size of each semiconductor region is not limited to this. For example, the fifth semiconductor region 315 may be formed to be larger than the third semiconductor region 313 so that charges are collected in the first semiconductor region 311 from a wider range.

[0050] Furthermore, the third semiconductor region 313 may be a P-type semiconductor region instead of an N-type. In this case, the impurity concentration of the third semiconductor region 313 is set lower than the impurity concentration of the second semiconductor region 312. If the impurity concentration of the third semiconductor region 313 is too high, an avalanche multiplication region is formed between the third semiconductor region 313 and the first semiconductor region 311, and the DCR (Dark Count Rate) increases.

[0051] A trench-based uneven structure 325 is formed on the surface of the semiconductor layer on the light incident side. The uneven structure 325 is surrounded by a P-type fourth semiconductor region 314, and scatters light incident on the photoelectric conversion element 102. Since the incident light travels obliquely inside the photoelectric conversion element, an optical path length equal to or greater than the thickness of the semiconductor layer 301 can be ensured, and light with a longer wavelength can be photoelectrically converted compared to a case without the uneven structure 325. In addition, the uneven structure 325 prevents the incident light from being reflected in the substrate, thereby improving the photoelectric conversion efficiency of the incident light. Furthermore, the light diffracted in an oblique direction by the uneven structure 325 is efficiently reflected by the wiring portion arranged in the vicinity of the surface opposite to the light incident surface, and the near-infrared sensitivity can be further improved.

[0052] The fifth semiconductor region 315 and the uneven structure 325 are formed so as to overlap in a plan view. The area where the fifth semiconductor region 315 and the uneven structure 325 overlap in a plan view is larger than the area of ​​the portion of the fifth semiconductor region 315 that does not overlap with the uneven structure 325. Charges generated at a position far from the avalanche multiplication region formed between the first semiconductor region 311 and the fifth semiconductor region 315 take a longer time to travel to the avalanche multiplication region than charges generated at a position close to the avalanche multiplication region. This may increase timing jitter. By arranging the fifth semiconductor region 315 and the uneven structure 325 at a position where they overlap in a plan view, the electric field deep in the photodiode can be increased, and the collection time of charges generated at a position far from the avalanche multiplication region can be shortened, thereby reducing timing jitter.

[0053] Furthermore, the fourth semiconductor region 314 three-dimensionally covers the concave-convex structure, so that the generation of thermally excited charges at the interface of the concave-convex structure can be suppressed, thereby suppressing the DCR of the photoelectric conversion element.

[0054] Pixels are separated from each other by a pixel isolation portion 324 having a trench structure, and a P-type seventh semiconductor region 317 formed around the same separates adjacent photoelectric conversion elements from each other by a potential barrier. Since the photoelectric conversion elements are also separated by the potential of the seventh semiconductor region 317, a trench structure such as the pixel isolation portion 324 is not essential as a pixel isolation portion, and the depth and position thereof are not limited to the configuration of FIG. 6 even when providing the pixel isolation portion 324 having a trench structure. The pixel isolation portion 324 may be a DTI (deep trench isolation) that penetrates the semiconductor layer, or may be a DTI that does not penetrate the semiconductor layer. Metal may be embedded in the DTI to improve the light shielding performance. The pixel isolation portion 324 may be composed of SiO, a fixed charge film, a metal member, polysilicon, or a combination of a plurality of these. The pixel isolation portion 324 may be configured to surround the entire circumference of the photoelectric conversion element in plan view, or may be configured only at the opposite side portions of the photoelectric conversion element, for example. A voltage may be applied to the embedded member to induce charges at the trench interface to suppress DCR.

[0055] The distance from the pixel isolation portion to the pixel isolation portion of an adjacent pixel or a pixel provided at the closest position can also be regarded as the size of one photoelectric conversion element 102. When the size of one photoelectric conversion element 102 is L, the distance d from the light incident surface to the avalanche multiplication region satisfies L√2 / 4 < d < L×√2. When the size and depth of the photoelectric conversion element satisfy this relational expression, the electric field strength in the depth direction and the electric field strength in the plane direction in the vicinity of the first semiconductor region 311 become comparable. Since the variation in the time required for charge collection can be suppressed, the timing jitter can be reduced and improved.

[0056] A pinning film 321, a planarization film 322, and a microlens 323 are further formed on the light incident surface side of the semiconductor layer. A filter layer (not shown) or the like may be further disposed on the light incident surface side. Various optical filters such as a color filter, an infrared cut filter, and a monochrome filter can be used for the filter layer. An RGB color filter, an RGBW color filter, or the like can be used for the color filter.

[0057] A wiring structure including a conductor and an insulating film is provided on the surface of the semiconductor layer facing the light incident surface. The photoelectric conversion element 102 shown in FIG. 6 has an oxide film 341 and a protective film 342 from the side closer to the semiconductor layer, and a wiring layer made of a conductor is further laminated. A wiring interlayer film 343, which is an insulating film, is provided between the wiring and the semiconductor layer and between the wiring layers. The protective film 342 is a film for protecting the APD from plasma damage and metal contamination during etching. SiN, which is a nitride film, is generally used, but SiON, SiC, SiCN, etc. may also be used.

[0058] The cathode wiring 331A is connected to the first semiconductor region 311, and the anode wiring 331B supplies a voltage to the seventh semiconductor region 317 via the ninth semiconductor region 319, which is an anode contact. In this embodiment, the cathode wiring 331A and the anode wiring 331B are arranged in the same wiring layer. The wiring portion is made of a conductor whose main material is a metal such as Cu or Al.

[0059] The resistive element 332 is connected to the cathode wiring 331A and functions as a quench resistor. Here, the resistive element 332 is formed on the opposite side of the semiconductor substrate from the cathode wiring 331A and the anode wiring 332B. The material used for the resistive element 332 may be a silicon-based material such as polysilicon or amorphous silicon, or may be a transparent electrode made of an inorganic material, a metal thin film material such as NiCr, a ceramic material such as TiN, TaN, TaSi, or WN, or an organic material. It is desirable that the material used for the resistive element 332 has a higher resistivity than the main material used for the cathode wiring 331A and the anode wiring 331B. The resistive element 332 is connected to the wiring portion 333A through a via 335. The wiring portion 333B is a wiring provided in the same wiring layer as the wiring portion 333A.

[0060] Fig. 7 is a pixel plan view of two pixels of the photoelectric conversion device according to the first embodiment, Fig. 7(a) is a plan view of each semiconductor region as viewed from the surface opposite to the light incident surface, and Fig. 7(b) is a plan view of a wiring portion as viewed from the surface opposite to the light incident surface.

[0061] 7(a), the first semiconductor region 311, the third semiconductor region 313, and the fifth semiconductor region 315 are circular and arranged concentrically. With this structure, it is possible to suppress local electric field concentration at the end of the strong electric field region between the first semiconductor region 311 and the second semiconductor region 312, thereby obtaining the effect of reducing the DCR. The shape of each semiconductor region is not limited to a circle, and may be, for example, a polygon with the center of gravity aligned.

[0062] In FIG. 7(b), the resistive element 332 is formed in a thin line pattern and is electrically connected to the cathode wiring 331A and the power supply wiring 333B through a via and a wiring layer. A via 335 is formed on the resistive element 332 and is electrically connected to the wiring portion 333A. The wiring portion 333A is electrically connected to the signal processing portion 103 arranged on the circuit board 21 through a connection wiring provided for each pixel. The resistance value of the resistive element 332 needs to be set high enough to quench the multiplied current of the APD, and a resistance of at least 10 kOhm is required. The resistance value of the resistive element 332 is preferably 50 kOhm or more, for example, but may be about 30 kOhm. On the other hand, considering the time required from the change in potential accompanying the occurrence of avalanche multiplication to recovery, it is desirable for the resistance value to be 1 MOhm or less. In order to realize a high resistance value within a limited pixel area, it is preferable to make the cross-sectional area of ​​the resistive element sufficiently small, and for example, it is preferable to set the thickness of the resistive element to 1 / 10 or less of the width of the resistive element in a certain cross section. In other words, it is desirable that the ratio of the shortest side to the longest side of the resistor element in a certain cross section be 10 or more.

[0063] In the conventional pixel configuration, it was common to place a quench resistor element near the APD. In this case, especially when using fine pixels, it is necessary to place the resistor element near the main semiconductor region that induces avalanche multiplication and the guard ring region for electric field relaxation. At this time, there was a problem that the potential of the quench element placed near the APD and the potential fluctuation due to avalanche multiplication affect the electrostatic potential of the APD, and local electric field concentration occurs, thereby increasing noise. As shown in FIG. 6, in this embodiment, the resistor element 332 is formed on the opposite side of the semiconductor substrate from the cathode wiring 331A and the anode wiring 332B, so that the wiring portion shields electrostatic interference between the semiconductor substrate and the resistor element 332. In other words, the distance between the resistor element 332 and the first surface of the first semiconductor layer is longer than the distance between the anode wiring 332B and the first surface of the first semiconductor layer. This prevents the electrostatic potential of the quench element and its fluctuations from affecting the potential of the APD, preventing localized electric field concentration, thereby enabling both noise suppression and pixel integration.

[0064] Here, in order to enhance the effect of shielding electrostatic interference caused by the wiring portion, it is desirable that at least a part of the resistance element 332 overlaps with the wiring portion in a plan view, as shown in Fig. 7(b). Also, in order to enhance the effect of shielding electrostatic interference caused by the wiring portion, it is desirable that the thickness of the wiring portion is thicker than the thickness of the resistance element 332. Furthermore, it is desirable to arrange them in such a manner that the wiring portion overlaps on a straight line connecting a point on the PN junction (strong electric field region) that induces avalanche multiplication and a point in the resistance element 332.

[0065] Of the two pixels shown in Figures 6 and 7, the first resistor element 332 connected to the first avalanche photodiode on the left and the second resistor element 332 connected to the second avalanche photodiode on the right are provided at the same height in the wiring structure. In other words, the first resistor element 332 and the second resistor element 332 are formed on the same plane parallel to the surface of the first semiconductor layer. It can also be said that the first resistor element 332 and the second resistor element 332 are provided in the same wiring layer in the wiring structure.

[0066] In this embodiment, a sensor configuration in which the sensor substrate 11 and the circuit substrate 21 are stacked has been described. However, the sensor substrate 11 may be provided with circuits such as the signal processing unit 103, and the photoelectric conversion element may be formed only by the sensor substrate 11.

[0067] Second Embodiment A photoelectric conversion device according to the second embodiment will be described with reference to Fig. 8 to Fig. 10. Portions common to the first embodiment will be omitted, and differences from the first embodiment will be mainly described. In this embodiment, a configuration that facilitates integration of pixel circuits will be described.

[0068] In this embodiment, a resistive element 222 is provided between the APD 201 and the resistive element 202 in parallel with the resistive element 202. Unlike the first embodiment, the signal amplitude is reduced by the resistive voltage division effect. This eliminates the need to use a high-voltage element in the input stage of the waveform shaping unit 210, facilitating integration of pixel circuits. The signal amplitude can be further reduced by making the resistance value of the resistive element 221 larger than the resistance value of the resistive element 201. The total value of the resistance value of the resistive element 202 and the resistance value of the resistive element 221 needs to be set sufficiently high to quench the multiplied current of the APD, similar to the resistive element 332, and is preferably, for example, 50 kOhm or more. In addition, it is desirable for the voltage division ratio to reduce the signal amplitude to about 0.9 to 0.01 times, and for example, the resistance value of the resistive element 202 may be set to about 10 kOhm, and the resistance value of the resistive element 221 may be set to about 40 kOhm.

[0069] FIG. 8 is an example of a block diagram including an equivalent circuit of a pixel unit of a photoelectric conversion device according to the second embodiment.

[0070] Fig. 9 is a cross-sectional view of two pixels of photoelectric conversion elements 102 of a photoelectric conversion device according to the second embodiment, taken in a direction perpendicular to the surface direction of the substrate, and corresponds to the A-A' cross section in Fig. 10(a). This embodiment differs from the first embodiment in that the wiring portion 333A is not directly connected to the portion where the cathode wiring 331A and the resistance element 332 are connected. In other words, the cathode wiring 331A and the wiring portion 333A are connected via the resistance element 332.

[0071] Fig. 10 is a pixel plan view of two pixels of a photoelectric conversion device according to the second embodiment, Fig. 10(a) is a plan view of each semiconductor region as viewed from the surface opposite to the light incident surface, and Fig. 10(b) is a plan view of a wiring portion as viewed from the surface opposite to the light incident surface.

[0072] FIG. 10(a) is equivalent to FIG. 7(a) according to the first embodiment.

[0073] In FIG. 10(b), the resistive element 332 is formed in a thin line pattern and is electrically connected to the cathode wiring 331A and the power supply wiring 333B through vias. A via 335 is formed on the middle part of the resistive element 332 and is electrically connected to the wiring portion 333A. The wiring portion 333A is electrically connected to the signal processing portion 103 arranged on the circuit board 21 through a connection wiring provided for each pixel. In FIG. 10(b), the cathode wiring 331A and the wiring portion 333A overlap in a planar view, but the via 335 connecting the cathode wiring 331A and the wiring portion 333A does not overlap with the cathode wiring 331A or the wiring portion 333A in a planar view. The position of the via 335 is not limited to the arrangement in FIG. 10(b).

[0074] In the plan view shown in Fig. 10, elements corresponding to the resistive element 202 and the resistive element 221 in Fig. 8 are continuously formed by one resistive element 332. This makes it easy to reduce the layout area of ​​the resistive element, but the two resistive elements may be physically separated and laid out. For example, the resistive element 202 and the resistive element 221 may be provided in different wiring layers, and the resistive elements 202 and 221 may be electrically connected to each other by a member whose main material is different from that of the resistive element 221.

[0075] (Modification of the second embodiment) A photoelectric conversion device according to a modification of the second embodiment will be described with reference to FIG.

[0076] The following description will omit the parts common to the first and second embodiments, and will mainly describe the parts different from the second embodiment. In this embodiment, a pixel configuration that is easy to manufacture will be described.

[0077] FIG. 11 is an example of a cross-sectional view of a wiring part of a pixel according to a modification of the second embodiment. An example of a method of connecting a resistive element 332 to surrounding electrodes is shown for the surfaces corresponding to the A surface and the B surface shown in FIG. 9. During manufacturing, layers are stacked in order starting from the layer closest to the A surface side to form a wiring layer. In FIG. 11(i), a contact plug (or via) 334 is formed, and then the resistive element 332 is stacked. In FIG. 11(ii), both vias provided on the A surface side and vias provided on the B surface side of the resistive element 332 are mixed. In FIG. 11(iii), one end of the resistive element 332 also serves as a barrier metal for the bottom surface (A surface side) of the wiring part 336. In FIG. 11(iv), a via is provided from the resistive element 332 toward the B surface side. In FIG. 11(v), both ends of the resistive element 332 also serve as a barrier metal for the wiring part 336. In FIG. 11(vi), after the wiring is formed, a resistor element 332 is formed so as to also function as a barrier metal on the upper surface of the wiring.

[0078] As described above, electrical connection may be made to the resistive element 332 using contacts or vias used in a general manufacturing method, or the resistive element 332 may also serve as part of the barrier metal of the wiring portion. In this way, by combining with a general semiconductor manufacturing method, a pixel structure that has a high layout area efficiency and is easy to manufacture can be realized.

[0079] (Third embodiment) A photoelectric conversion device according to the third embodiment will be described with reference to Fig. 12 to Fig. 14. Portions common to the first and second embodiments will be omitted, and mainly portions different from the first embodiment will be described. This embodiment differs from the first and second embodiments in that the resistive element 332A and the resistive element 332B have a via-type structure extending in a direction perpendicular to the substrate surface, which facilitates further integration of pixels.

[0080] 12 is an example of a block diagram including an equivalent circuit of a pixel unit of a photoelectric conversion device according to the third embodiment. In this embodiment, a resistive element 222 is provided between the cathode terminal of the APD 201 and the waveform shaping unit 210. A waveform with an amplitude lower than the signal amplitude of VC is input to the waveform shaping unit 210 due to a low-pass filter effect defined by the resistance of the resistive element 222 and the input capacitance of the waveform shaping unit 210. This eliminates the need to use a high-voltage element in the input stage of the waveform shaping unit 210, facilitating integration of pixel circuits. Furthermore, since the resistive element 202 is the only one connected in series to the APD 201, it is easier to shorten the Dead Time compared to the second embodiment.

[0081] In FIG. 11, a resistive element may be added between the APD 201 and the terminal indicated by VC, bringing the total number of resistive elements to three.

[0082] FIG. 13 is a cross-sectional view of two pixels of photoelectric conversion elements 102 of a photoelectric conversion device according to the third embodiment, taken in a direction perpendicular to the surface direction of the substrate, and corresponds to the AA' cross section in FIG. 14(a).

[0083] The cathode electrode 331A is connected to the wiring portion 337 through a via made of a normal metal material such as Cu, and the wiring portion 337 is connected to the wiring portion 333A and the power wiring 333B through a via-type resistance element 332A and a resistance element 332B made of a high resistance material. The via-type resistance element has a smaller diameter than a normal via. The material of the barrier layer of the via-type resistance element may be different from the material of the barrier layer of a normal via. In addition, it is desirable that the thickness of the interlayer film in which the via-type resistance element is provided is thicker than the thickness of the interlayer film in which a normal via is provided.

[0084] Fig. 14 is a pixel plan view of two pixels of a photoelectric conversion device according to a third embodiment, Fig. 14(a) is a plan view of each semiconductor region as viewed from the surface opposite to the light incident surface, and Fig. 14(b) is a plan view of a wiring portion as viewed from the surface opposite to the light incident surface.

[0085] FIG. 14(a) is equivalent to FIG. 7(a) according to the first embodiment.

[0086] 14(b), the resistive element 332A is formed in a via-type pattern and is electrically connected to the wiring portion 337 and the wiring portion 333A. The resistive element 332B is formed in a via-type pattern and is electrically connected to the wiring portion 337 and the power supply wiring 333B. The wiring portion 333A is electrically connected to the signal processing portion 103 arranged on the circuit board 21 through a connection wiring provided for each pixel. In this embodiment, the via-type resistive elements corresponding to the resistive elements 202 and 221 in FIG. 12 are arranged in the same plane parallel to the substrate surface, but may be formed by stacking in a direction perpendicular to the substrate surface.

[0087] In this embodiment, by using a via-type resistance element, the area efficiency of the layout is improved, and pixel integration becomes easier.

[0088] (Fourth embodiment) The photoelectric conversion system according to this embodiment will be described with reference to Fig. 15. Fig. 15 is a block diagram showing a schematic configuration of the photoelectric conversion system according to this embodiment.

[0089] The photoelectric conversion devices described in the first to sixth embodiments are applicable to various photoelectric conversion systems. Examples of the applicable photoelectric conversion systems include digital still cameras, digital camcorders, security cameras, copiers, fax machines, mobile phones, car-mounted cameras, and observation satellites. Camera modules equipped with an optical system such as a lens and an imaging device are also included in the photoelectric conversion systems. FIG. 15 illustrates a block diagram of a digital still camera as an example of these.

[0090] 15 includes an image pickup device 1004, which is an example of a photoelectric conversion device, and a lens 1002 that forms an optical image of a subject on the image pickup device 1004. The system further includes an aperture 1003 that varies the amount of light passing through the lens 1002, and a barrier 1001 that protects the lens 1002. The lens 1002 and the aperture 1003 form an optical system that focuses light on the image pickup device 1004. The image pickup device 1004 is a photoelectric conversion device according to any one of the above embodiments, and converts the optical image formed by the lens 1002 into an electrical signal.

[0091] The photoelectric conversion system also has a signal processing unit 1007 which is an image generating unit that generates an image by processing an output signal output from the imaging device 1004. The signal processing unit 1007 performs various corrections and compression as necessary to output image data. The signal processing unit 1007 may be formed on the semiconductor substrate on which the imaging device 1004 is provided, or may be formed on a semiconductor substrate separate from the imaging device 1004.

[0092] The photoelectric conversion system further includes a memory unit 1010 for temporarily storing image data, and an external interface unit (external I / F unit) 1013 for communicating with an external computer or the like. The photoelectric conversion system further includes a recording medium 1012 such as a semiconductor memory for recording or reading out imaging data, and a recording medium control interface unit (recording medium control I / F unit) 1011 for recording or reading out data on the recording medium 1012. The recording medium 1012 may be built into the photoelectric conversion system, or may be removable.

[0093] The photoelectric conversion system further includes an overall control / calculation unit 1009 that performs various calculations and controls the entire digital still camera, and a timing generation unit 1008 that outputs various timing signals to the image capture device 1004 and the signal processing unit 1007. Here, the timing signals and the like may be input from outside, and the photoelectric conversion system only needs to include at least the image capture device 1004 and the signal processing unit 1007 that processes the output signal output from the image capture device 1004.

[0094] The imaging device 1004 outputs an imaging signal to a signal processing unit 1007. The signal processing unit 1007 performs predetermined signal processing on the imaging signal output from the imaging device 1004, and outputs image data. The signal processing unit 1007 generates an image using the imaging signal.

[0095] In this way, according to this embodiment, it is possible to realize a photoelectric conversion system to which the photoelectric conversion device (imaging device) according to any one of the above embodiments is applied.

[0096] Fifth embodiment The photoelectric conversion system and the moving object of this embodiment will be described with reference to Fig. 16. Fig. 16 is a diagram showing the configuration of the photoelectric conversion system and the moving object of this embodiment.

[0097] FIG. 16(a) shows an example of a photoelectric conversion system related to an in-vehicle camera. The photoelectric conversion system 2300 has an imaging device 2310. The imaging device 2310 is the photoelectric conversion device described in any of the above embodiments. The photoelectric conversion system 2300 has an image processing unit 2312 that performs image processing on a plurality of image data acquired by the imaging device 2310, and a parallax acquisition unit 2314 that calculates parallax (phase difference of parallax images) from the plurality of image data acquired by the photoelectric conversion system 2300. The photoelectric conversion system 2300 also has a distance acquisition unit 2316 that calculates a distance to an object based on the calculated parallax, and a collision determination unit 2318 that determines whether or not there is a possibility of collision based on the calculated distance. Here, the parallax acquisition unit 2314 and the distance acquisition unit 2316 are examples of distance information acquisition means that acquire distance information to an object. That is, the distance information is information on the parallax, the defocus amount, the distance to the object, and the like. The collision determination unit 2318 may determine the possibility of a collision using any of these pieces of distance information. The distance information acquisition means may be realized by dedicated hardware, or may be realized by a software module. In addition, it may be realized by a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or the like, or may be realized by a combination of these.

[0098] The photoelectric conversion system 2300 is connected to a vehicle information acquisition device 2320, and can acquire vehicle information such as vehicle speed, yaw rate, and steering angle. The photoelectric conversion system 2300 is also connected to a control ECU 2330, which is a control unit that outputs a control signal to generate a braking force for the vehicle based on the judgment result of the collision judgment unit 2318. The photoelectric conversion system 2300 is also connected to an alarm device 2340 that issues an alarm to the driver based on the judgment result of the collision judgment unit 2318. For example, when the judgment result of the collision judgment unit 2318 indicates that there is a high possibility of a collision, the control ECU 2330 performs vehicle control to avoid a collision and reduce damage by applying the brakes, releasing the accelerator, suppressing engine output, etc. The alarm device 2340 warns the user by sounding an alarm, displaying alarm information on the screen of a car navigation system, etc., or vibrating the seat belt or steering wheel.

[0099] In this embodiment, the surroundings of the vehicle, for example, the front or rear, are imaged by the photoelectric conversion system 2300. Fig. 16(b) shows a photoelectric conversion system for imaging the area in front of the vehicle (imaging range 2350). A vehicle information acquisition device 2320 sends an instruction to the photoelectric conversion system 2300 or the imaging device 2310. This configuration can further improve the accuracy of distance measurement.

[0100] Although the above describes an example of control to prevent collision with other vehicles, the present invention can also be applied to control of automatic driving by following other vehicles, control of automatic driving to prevent deviation from lanes, etc. Furthermore, the photoelectric conversion system is not limited to vehicles such as the vehicle itself, but can be applied to moving bodies (moving devices) such as ships, aircraft, and industrial robots. In addition, the present invention can be applied not only to moving bodies, but also to a wide range of devices that use object recognition, such as intelligent transport systems (ITS).

[0101] Sixth embodiment The photoelectric conversion system of this embodiment will be described with reference to Fig. 17. Fig. 17 is a block diagram showing an example of the configuration of a range image sensor which is the photoelectric conversion system of this embodiment.

[0102] 17, the distance image sensor 401 is configured to include an optical system 407, a photoelectric conversion device 408, an image processing circuit 404, a monitor 405, and a memory 406. The distance image sensor 401 can obtain a distance image according to the distance to the subject by receiving light (modulated light or pulsed light) that is projected from a light source device 411 toward the subject and reflected by the surface of the subject.

[0103] The optical system 407 is configured to have one or more lenses, and guides image light (incident light) from a subject to a photoelectric conversion device 408 , forming an image on the light receiving surface (sensor portion) of the photoelectric conversion device 408 .

[0104] As the photoelectric conversion device 408 , the photoelectric conversion device of each of the above-mentioned embodiments is applied, and a distance signal indicating a distance determined from a light reception signal output from the photoelectric conversion device 408 is supplied to the image processing circuit 404 .

[0105] The image processing circuit 404 performs image processing to construct a distance image based on the distance signal supplied from the photoelectric conversion device 408. The distance image (image data) obtained by this image processing is then supplied to a monitor 405 for display, or supplied to a memory 406 for storage (recording).

[0106] In the range image sensor 401 configured in this way, by applying the above-described photoelectric conversion device, it is possible to obtain, for example, a more accurate range image as the pixel characteristics improve.

[0107] Seventh embodiment The photoelectric conversion system of this embodiment will be described with reference to Fig. 18. Fig. 18 is a diagram showing an example of a schematic configuration of an endoscopic surgery system which is the photoelectric conversion system of this embodiment.

[0108] 18 shows a state in which an operator (doctor) 1131 is performing surgery on a patient 1132 on a patient bed 1133 using an endoscopic surgery system 1150. As shown in the figure, the endoscopic surgery system 1150 is composed of an endoscope 1100, a surgical tool 1110, and a cart 1134 on which various devices for endoscopic surgery are mounted.

[0109] The endoscope 1100 is composed of a lens barrel 1101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 1132, and a camera head 1102 connected to the base end of the lens barrel 1101. In the illustrated example, the endoscope 1100 is configured as a so-called rigid lens barrel having a rigid lens barrel 1101, but the endoscope 1100 may be configured as a so-called flexible lens barrel having a flexible lens barrel.

[0110] An opening into which an objective lens is fitted is provided at the tip 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 to the tip of the lens barrel 1101 by a light guide extending inside the lens barrel 1101, and is irradiated via the objective lens toward an observation target in a body cavity of a patient 1132. The endoscope 1100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0111] An optical system and a photoelectric conversion device are provided inside the camera head 1102, and reflected light (observation light) from an observation target is collected on the photoelectric conversion device by the optical system. The observation light is photoelectrically converted by the photoelectric conversion device to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to an observation image. The photoelectric conversion device described in each of the above-mentioned embodiments can be used as the photoelectric conversion device. The image signal is transmitted to a camera control unit (CCU: Camera Control Unit) 1135 as RAW data.

[0112] The CCU 1135 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and performs overall control of the operations of the endoscope 1100 and the display device 1136. Furthermore, the CCU 1135 receives an image signal from the camera head 1102, and performs various types of image processing on the image signal, such as development processing (demosaic processing), for displaying an image based on the image signal.

[0113] Under the control of the CCU 1135 , the display device 1136 displays an image based on an image signal that has been subjected to image processing by the CCU 1135 .

[0114] The light source device 1203 is composed of a light source such as an LED (Light Emitting Diode), and supplies the endoscope 1100 with irradiation light when photographing an operation site or the like.

[0115] The input device 1137 is an input interface for the endoscopic surgery system 1150. A user can input various information and instructions to the endoscopic surgery system 1150 via the input device 1137.

[0116] The treatment tool control device 1138 controls the driving of the energy treatment tool 1112 for cauterizing tissue, incising, sealing blood vessels, or the like.

[0117] The light source device 1203 that supplies irradiation light to the endoscope 1100 when photographing the surgical site can be composed of a white light source composed of, for example, an LED, a laser light source, or a combination of these. When the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so that the white balance of the captured image can be adjusted in the light source device 1203. In this case, it is also possible to capture images corresponding to each of the RGB colors in a time-division manner by irradiating the observation target with laser light from each of the RGB laser light sources in a time-division manner and controlling the driving of the image sensor of the camera head 1102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter to the image sensor.

[0118] Furthermore, the light source device 1203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. By controlling the driving of the image sensor of the camera head 1102 in synchronization with the timing of the change in the light intensity to acquire images in a time-division manner and synthesizing the images, it is possible to generate an image with a high dynamic range that is free of so-called blocked-up shadows and blown-out highlights.

[0119] The light source device 1203 may be configured to supply light in a predetermined wavelength band corresponding to the special light observation. In the special light observation, for example, the wavelength dependency of light absorption in body tissue is utilized. Specifically, a predetermined tissue such as blood vessels on the mucous membrane surface is photographed with high contrast by irradiating light in a narrower band than the irradiation light (i.e., white light) in normal observation. Alternatively, the special light observation may be a fluorescent observation in which an image is obtained by fluorescence generated by irradiating excitation light. In the fluorescent observation, it is possible to irradiate excitation light to the body tissue and observe the fluorescence from the body tissue, or to locally inject a reagent such as indocyanine green (ICG) into the body tissue and irradiate the body tissue with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 1203 may be configured to supply narrow band light and / or excitation light corresponding to such special light observation.

[0120] Eighth embodiment The photoelectric conversion system of this embodiment will be described with reference to Figs. 19(a) and (b). Fig. 19(a) describes glasses 1600 (smart glasses) which are the photoelectric conversion system of this embodiment. The glasses 1600 have a photoelectric conversion device 1602. The photoelectric conversion device 1602 is the photoelectric conversion device described in each of the above embodiments. A display device including a light-emitting device such as an OLED or LED may be provided on the back side of the lens 1601. The photoelectric conversion device 1602 may be one or more. A combination of multiple types of photoelectric conversion devices may also be used. The arrangement position of the photoelectric conversion device 1602 is not limited to that shown in Fig. 19(a).

[0121] The glasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the photoelectric conversion device 1602 and the display device. The control device 1603 also controls the operations of the photoelectric conversion device 1602 and the display device. The lens 1601 is formed with an optical system for focusing light on the photoelectric conversion device 1602.

[0122] FIG. 19(b) illustrates glasses 1610 (smart glasses) according to one application example. The glasses 1610 have a control device 1612, and the control device 1612 is equipped with a photoelectric conversion device corresponding to the photoelectric conversion device 1602 and a display device. The lens 1611 is formed with an optical system for projecting light emitted from the photoelectric conversion device in the control device 1612 and the display device, and an image is projected onto the lens 1611. The control device 1612 functions as a power source for supplying power to the photoelectric conversion device and the display device, and controls the operation of the photoelectric conversion device and the display device. The control device may have a line of sight detection unit that detects the line of sight of the wearer. Infrared light may be used for detecting the line of sight. The infrared light emission unit emits infrared light to the eyeball of a user gazing at a display image. An imaging unit having a light receiving element detects the reflected light of the emitted infrared light from the eyeball, thereby obtaining an image of the eyeball. By having a reduction means for reducing light from the infrared light emission unit to the display unit in a planar view, deterioration of image quality is reduced.

[0123] The gaze of the user with respect to the displayed image is detected from an image of the eyeball obtained by capturing infrared light. Any known method can be applied to gaze detection using the image of the eyeball. As an example, a gaze detection method based on a Purkinje image formed by reflection of irradiated light on the cornea can be used.

[0124] More specifically, the gaze detection process is performed based on the pupil-corneal reflex method. Using the pupil-corneal reflex method, a gaze vector that indicates the direction (rotation angle) of the eyeball is calculated based on the pupil image and the Purkinje image included in the captured image of the eyeball, thereby detecting the user's gaze.

[0125] The display device of this embodiment may have a photoelectric conversion device having a light receiving element, and may control the display image of the display device based on information about the user's line of sight from the photoelectric conversion device.

[0126] Specifically, the display device determines a first field of view area to which the user gazes and a second field of view area other than the first field of view area based on the line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be received from an external control device. In the display area of ​​the display device, the display resolution of the first field of view area may be controlled to be higher than the display resolution of the second field of view area. In other words, the resolution of the second field of view area may be lower than that of the first field of view area.

[0127] The display area may have a first display area and a second display area different from the first display area, and a high priority area may be determined from the first display area and the second display area based on line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be determined by an external control device and received. The resolution of the high priority area may be controlled to be higher than the resolution of areas other than the high priority area. In other words, the resolution of an area with a relatively low priority may be lowered.

[0128] AI may be used to determine the first field of view area and areas with high priority. The AI ​​may be a model configured to estimate the angle of the line of sight and the distance to an object at the end of the line of sight from the image of the eyeball, using as teacher data an image of the eyeball and the direction in which the eyeball in the image was actually looking. The AI ​​program may be included in the display device, the photoelectric conversion device, or an external device. If included in the external device, it is transmitted to the display device via communication.

[0129] When display control is performed based on visual recognition detection, the present invention is preferably applicable to smart glasses further including a photoelectric conversion device for capturing an image of the outside world. The smart glasses can display captured outside information in real time.

[0130] [Modified embodiment] The present invention is not limited to the above-described embodiment, and various modifications are possible.

[0131] For example, an example in which part of the configuration of any one of the embodiments is added to another embodiment, or an example in which part of the configuration of another embodiment is substituted therefor, is also included in the embodiments of the present invention.

[0132] Further, the photoelectric conversion systems shown in the fourth and fifth embodiments are examples of photoelectric conversion systems to which the photoelectric conversion device can be applied, and the photoelectric conversion systems to which the photoelectric conversion device of the present invention can be applied are not limited to the configurations shown in Fig. 15 to Fig. 16. The same applies to the ToF system shown in the sixth embodiment, the endoscope shown in the seventh embodiment, and the smart glasses shown in the eighth embodiment.

[0133] The photoelectric conversion device of each of the above-mentioned embodiments can also be applied to sensors inside an automobile. For example, the device can be applied to sensors used to detect the driver's face, facial expression, and line of sight. The output of the sensor can be used to detect the driver's lack of attention, drowsiness, fainting, etc. Also, the driver can be identified.

[0134] It should be noted that the above-mentioned embodiments are merely examples of the implementation of the present invention, and the technical scope of the present invention should not be interpreted as being limited by these embodiments. In other words, the present invention can be implemented in various forms without departing from its technical concept or main features.

[0135] The present disclosure also includes the following configuration.

[0136] (Configuration 1) A photoelectric conversion device having a first substrate including a first semiconductor layer having a first surface and a second surface, and a first wiring structure arranged on the first semiconductor layer, the photoelectric conversion device including an avalanche photodiode provided in the first semiconductor layer, and a resistive element connected to the avalanche photodiode, the first wiring structure having wiring that supplies a first voltage to the avalanche photodiode, and the distance between the resistive element and the first surface of the first semiconductor layer is longer than the distance between the wiring and the first surface of the first semiconductor layer.

[0137] (Configuration 2) The photoelectric conversion device according to configuration 1, further comprising a second semiconductor layer laminated on the first substrate.

[0138] (Configuration 3) The photoelectric conversion device according to configuration 2, further comprising a waveform shaping section disposed on the second semiconductor layer for shaping an output signal of the avalanche photodiode.

[0139] (Configuration 4) A plurality of the avalanche photodiodes are provided, The photoelectric conversion device according to any one of configurations 1 to 3, wherein among the plurality of avalanche photodiodes, a first resistive element connected to a first avalanche photodiode and a second resistive element connected to a second avalanche photodiode are provided on the same plane parallel to a surface of the first semiconductor layer.

[0140] (Configuration 5) The photoelectric conversion device according to any one of configurations 1 to 4, wherein the resistive element includes polysilicon or amorphous silicon.

[0141] (Configuration 6) The photoelectric conversion device according to any one of configurations 1 to 5, wherein the resistive element includes a metal thin film material.

[0142] (Configuration 7) The photoelectric conversion device according to any one of configurations 1 to 6, wherein the resistor element includes a ceramic material.

[0143] (Configuration 8) The photoelectric conversion device according to any one of configurations 1 to 7, wherein the resistor element contains an organic material.

[0144] (Configuration 9) The photoelectric conversion device according to any one of configurations 1 to 8, wherein the ratio of the shortest side to the longest side of the resistor element is 10 or more.

[0145] (Configuration 10) The photoelectric conversion device according to any one of configurations 1 to 9, wherein the resistor element is made of a material having a higher resistivity than a main material of the wiring.

[0146] (Configuration 11) The photoelectric conversion device according to any one of configurations 1 to 10, wherein the resistive element is composed of a material having a higher resistivity than a main material of a via that supplies voltage to the avalanche photodiode.

[0147] (Configuration 12) The photoelectric conversion device according to any one of configurations 1 to 11, wherein the resistive element overlaps with the cathode of the avalanche photodiode in a plan view.

[0148] (Configuration 13) The photoelectric conversion device according to any one of configurations 1 to 12, wherein a resistive element is connected to both the cathode and the anode of the avalanche photodiode.

[0149] (Configuration 14) The photoelectric conversion device according to any one of configurations 1 to 13, wherein the resistor element extends in a direction perpendicular to a surface of the first substrate.

[0150] (Configuration 15) A photoelectric conversion device according to any one of configurations 1 to 14, characterized in that two power supply wiring systems for supplying voltages to the cathode and anode of the avalanche photodiode respectively are arranged on the first substrate.

[0151] (Configuration 16) The photoelectric conversion device according to any one of configurations 1 to 15, wherein at least a portion of the wiring overlaps with the resistance element in a plan view.

[0152] (Configuration 17) A photoelectric conversion device described in any one of configurations 1 to 16, characterized in that the thickness of the resistor element in a direction perpendicular to the first substrate is smaller than the thickness of the wiring in a direction perpendicular to the first substrate.

[0153] (Configuration 18) The photoelectric conversion device according to any one of configurations 1 to 17, wherein the wiring is arranged on a line connecting a multiplication region of the avalanche photodiode and a certain point of the resistance element.

[0154] (Configuration 19) The photoelectric conversion device according to any one of configurations 1 to 18, wherein contact plugs are connected to both the upper and lower sides of the resistive element.

[0155] (Configuration 20) The photoelectric conversion device according to any one of configurations 1 to 19, wherein the resistance value of the resistive element is 50 kOhm or more.

[0156] (Configuration 21) The photoelectric conversion device according to any one of configurations 1 to 20, a signal processing unit that generates an image using a signal output from the photoelectric conversion device.

[0157] (Configuration 22) A moving body including a photoelectric conversion device according to any one of configurations 1 to 20, characterized in that the moving body has a control unit that controls the movement of the moving body using a signal output by the photoelectric conversion device. [Explanation of symbols]

[0158] 100 Photoelectric conversion device 201 Avalanche photodiode 202 Resistance element 331A Cathode Wiring 331B Anode wiring

Claims

1. A photoelectric conversion device having a first substrate having a first semiconductor layer having a first surface and a second surface, and a first wiring structure disposed on the first semiconductor layer, An avalanche photodiode provided in the first semiconductor layer, And a resistive element connected to the avalanche photodiode, The first wiring structure has a first wiring for supplying a first voltage to the avalanche photodiode and a second wiring for supplying a second voltage to the avalanche photodiode, The distance between the resistive element and the first surface of the first semiconductor layer is longer than the distance between the first wiring and the first surface of the first semiconductor layer and the distance between the second wiring and the first surface of the first semiconductor layer. A photoelectric conversion device characterized by that.

2. The photoelectric conversion device according to claim 1, further comprising a second semiconductor layer laminated on the first substrate.

3. The photoelectric conversion device according to claim 2, further comprising a waveform shaping unit disposed in the second semiconductor layer for shaping an output signal of the avalanche photodiode.

4. Having a plurality of the avalanche photodiodes, Among the plurality of avalanche photodiodes, a first resistive element connected to a first avalanche photodiode and a second resistive element connected to a second avalanche photodiode are provided on the same plane parallel to the surface of the first semiconductor layer. The photoelectric conversion device according to claim 1, characterized by that.

5. The resistive element includes polysilicon or amorphous silicon. The photoelectric conversion device according to claim 1, characterized by that.

6. The resistive element includes a metal thin film material. The photoelectric conversion device according to claim 1, characterized by that.

7. The photoelectric conversion device according to claim 1, wherein the resistance element contains a ceramic material.

8. The photoelectric conversion device according to claim 1, wherein the resistance element contains an organic material.

9. The photoelectric conversion device according to claim 1, wherein a ratio of the shortest side to the longest side of the resistance element is 10 or more.

10. The photoelectric conversion device according to claim 1, wherein the resistance element is configured to contain a material having a higher resistivity than a main material of the first wiring.

11. The photoelectric conversion device according to claim 1, wherein the resistance element is configured to contain a material having a higher resistivity than a main material of a via that supplies a voltage to the avalanche photodiode.

12. The photoelectric conversion device according to claim 1, wherein the resistance element overlaps with a cathode of the avalanche photodiode in a plan view.

13. The photoelectric conversion device according to claim 1, wherein resistance elements are connected to both a cathode and an anode of the avalanche photodiode.

14. The photoelectric conversion device according to claim 2, wherein the resistance element extends in a direction perpendicular to a substrate surface of the first substrate.

15. The photoelectric conversion device according to claim 1, wherein the first wiring and the second wiring, which are two systems of power supply wirings that supply voltages to the cathode and the anode of the avalanche photodiode, respectively, are arranged on the first substrate.

16. The photoelectric conversion device according to claim 1, wherein at least a part of the first wiring overlaps with the resistance element in a plan view.

17. The thickness of the resistance element in the direction perpendicular to the first substrate is smaller than the thickness of the first wiring in the direction perpendicular to the first substrate, according to the photoelectric conversion device described in claim 2.

18. The first wiring is arranged on a line connecting a multiplication region of the avalanche photodiode and a point of the resistance element, according to the photoelectric conversion device described in claim 1.

19. Contact plugs are connected to both the lower side and the upper side of the resistance element, according to the photoelectric conversion device described in claim 1.

20. The resistance value of the resistance element is 50 kOhm or more, according to the photoelectric conversion device described in claim 1.

21. A photoelectric conversion device according to any one of claims 1 to 20, A signal processing unit that generates an image using a signal output by the photoelectric conversion device, characterized by a photoelectric conversion system.

22. A moving body including the photoelectric conversion device according to any one of claims 1 to 20, Having a control unit that controls the movement of the moving body using a signal output by the photoelectric conversion device Characterized by a moving body.

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