Photoelectric conversion device, and photoelectric conversion system

Abstract

To achieve both an improvement in performance and miniaturization of a pixel.SOLUTION: A photoelectric conversion device has a first substrate that includes a first semiconductor layer and a first wiring structure laminated on the first semiconductor layer, and a second substrate that includes a second semiconductor layer and a second wiring structure laminated on the second semiconductor layer, and includes: an avalanche photodiode arranged on the first semiconductor layer; a first resistance element arranged on the first substrate and connected with the avalanche photodiode; a waveform shaping unit arranged on the second semiconductor layer and shaping an output signal from the avalanche photodiode; and a second resistance element arranged on the first substrate and connected with the avalanche photodiode, the waveform shaping unit, and the first resistance element.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] As a means for expanding the pixel area of ​​a photoelectric conversion device using an avalanche photodiode, a method is known in which a photoelectric conversion unit and a pixel circuit for processing a signal from the photoelectric conversion unit are arranged on different substrates and stacked. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2015 / 0115131 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the configuration described in Patent Document 1, when increasing the reverse bias applied to the avalanche photodiode, it is necessary to use a high-voltage transistor with a large element size in the pixel circuit. Therefore, there is a problem that it is difficult to achieve both high performance and miniaturization of the pixel. The present invention has been made in consideration of the above problem, and aims to achieve both high performance and miniaturization of the pixel. [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 and a first wiring structure stacked on the first semiconductor layer, and a second substrate including a second semiconductor layer and a second wiring structure stacked on the second semiconductor layer, the photoelectric conversion device comprising: an avalanche photodiode disposed on the first semiconductor layer; a first resistive element disposed on the first substrate and connected to the avalanche photodiode; a waveform shaping unit disposed on the second semiconductor layer and shaping an output signal of the avalanche photodiode; and a second resistive element disposed on the first substrate and connected to the avalanche photodiode, the waveform shaping unit, and the first resistive element. Effect of the Invention

[0006] According to the present invention, it is possible to achieve both high performance and miniaturization of pixels. [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 a photoelectric conversion device according to an 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] FIG. 1 is a schematic diagram showing driving of a pixel circuit of a photoelectric conversion device according to an embodiment; [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] FIG. 1 is a diagram illustrating the effects of the present invention. [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] 13 is a configuration example of a pixel circuit of a photoelectric conversion device according to a third embodiment. [Figure 12] 13 is a configuration example of a pixel circuit of a photoelectric conversion device according to a fourth embodiment. [Figure 13] 13 is a configuration example of a pixel circuit of a photoelectric conversion device according to a fifth embodiment. [Figure 14] 13 is a configuration example of a pixel circuit of a photoelectric conversion device according to a modified example of the fifth embodiment. [Figure 15] FIG. 13 is a functional block diagram of a photoelectric conversion system according to a sixth embodiment. [Figure 16] FIG. 13 is a functional block diagram of a photoelectric conversion system according to a seventh embodiment. [Figure 17] FIG. 13 is a functional block diagram of a photoelectric conversion system according to an eighth embodiment. [Figure 18] FIG. 13 is a functional block diagram of a photoelectric conversion system according to a ninth embodiment. [Figure 19] FIG. 23 is a functional block diagram of a photoelectric conversion system according to a tenth 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 first resistive element 202 is connected between a power supply that supplies a voltage VH and the APD 201. The first 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 first 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] A second resistive element 221 is provided between the first resistive element 202 and the APD 201. The provision of the second resistive element 221 is one of the features of the present invention, and the function thereof will be described later.

[0035] 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.

[0036] 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.

[0037] The counter circuit 211 counts the pulse signal output from the waveform shaping section 210 and holds the count value.

[0038] The electrical connection may be switched by disposing a switch such as a transistor between the first 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.

[0039] 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.

[0040] FIG. 5 is a diagram showing a schematic diagram of the relationship between the operation of an APD and an output signal.

[0041] Fig. 5(a) is a diagram excerpting the APD 201, the first resistive element 202, and the 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).

[0042] 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 first resistor 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.

[0043] 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.

[0044] The photoelectric conversion devices of the respective embodiments will be described below.

[0045] (First embodiment) The photoelectric conversion device according to the first embodiment will be described with reference to FIGS.

[0046] 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).

[0047] 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.

[0048] 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.

[0049] 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 .

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] In addition, by covering the fourth semiconductor region 314 three-dimensionally over the uneven structure, generation of thermally excited charges at the interface of the uneven structure can be suppressed. As a result, the DCR of the photoelectric conversion element is suppressed.

[0055] Pixels are separated from each other by a pixel isolation section 324 having a trench structure, and P-type seventh semiconductor regions 317 formed around the same separate 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 section 324 is not essential as a pixel isolation section, and even when providing the pixel isolation section 324 having a trench structure, its depth and position are not limited to the configuration of FIG. 6. The pixel isolation section 324 may be a DTI (deep trench isolation) penetrating the semiconductor layer or a DTI not penetrating the semiconductor layer. Metal may be embedded in the DTI to improve the light shielding performance. The pixel isolation section 324 may be composed of SiO, a fixed charge film, a metal member, polysilicon, or a combination of a plurality thereof. The pixel isolation section 324 may be configured to surround the entire circumference of the photoelectric conversion element in plan view, or may be configured only at opposite sides 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.

[0056] The distance from the pixel isolation section to the pixel isolation section 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 approximately the same. Since the variation in the time required for charge collection can be suppressed, timing jitter can be reduced and improved.

[0057] A pinning film 321, a planarizing film 322, and a microlens 323 are further disposed on the light incident surface side of the semiconductor layer. A filter layer (not shown) may be further disposed on the light incident surface side. The filter layer may be various optical filters such as a color filter, an infrared light cut filter, and a monochrome filter. The color filter may be an RGB color filter, an RGBW color filter, or the like.

[0058] 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.

[0059] 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 composed of a conductor mainly made of a metal such as Cu or Al. The resistive element 332 is connected to the cathode wiring 331A and functions as a quench resistor. 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.

[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 fine line pattern and is electrically connected to the cathode wiring 331A and the power supply wiring 333B through a contact plug and a wiring layer. A contact plug 335 is formed on the middle part of the resistive element 332 and is electrically connected to the wiring part 333A. The wiring part 333A is electrically connected to the signal processing part 103 arranged on the circuit board 21 through a connection wiring provided for each pixel. In this embodiment, elements corresponding to the first resistive element 202 and the second resistive element 221 in FIG. 4 are continuously formed by one resistive element 332, which makes it easy to reduce the layout area, 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 the resistive element 221 may be electrically connected to each other by a member whose main material is different from that of the resistive element 202.

[0063] The resistance value of the resistive element 332 must be set high enough to quench the multiplied current of the APD, and a resistance of 10 kOhm or more is required. The resistance value of the resistive element 332 is preferably 50 kOhm or more, for example, but may be 30 kOhm or more. On the other hand, considering the time required from the change in potential caused by the occurrence of avalanche multiplication to recovery, the resistance value is preferably 1 MOhm or less. In order to achieve 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 times the width of the resistive element. In other words, it is preferable that the ratio of the shortest side to the longest side of the resistive element in a certain cross section is 10 or more.

[0064] The effect of the present embodiment on the conventional configuration will be described with reference to FIG. 8. FIG. 8(a) shows the configuration and operation example of a conventional quench circuit. The APD 201 is connected in series to the first resistive element 202, and the photodiode capacitance Cpd and other parasitic capacitances Cro including the wiring capacitance and the gate capacitance of the readout circuit are added to the cathode terminal as parasitic capacitance components. The graph in FIG. 8(a) shows the time change of the cathode potential VC' when the APD 201 detects a photon. The dotted line corresponds to the case where the excess bias Vex is low, and the solid line corresponds to the case where the excess bias Vex is high. In general, by increasing the excess bias Vex applied to the APD, the photon detection efficiency can be increased and the timing jitter can be reduced. On the other hand, since the signal amplitude of VC' is approximately equal to Vex, the amplitude of the output waveform of VC' increases as Vex is increased, which may cause gate destruction of a transistor connected in the subsequent stage. If a high-voltage thick oxide film transistor is used to avoid gate destruction, the area occupied by the pixel circuit increases, making integration difficult. Therefore, it can be said that there is a trade-off between pixel performance such as photon detection efficiency and timing jitter, and pixel integration. For example, when Vex corresponding to the waveform shown by the solid line is applied, it is difficult to miniaturize the pixel circuit, so when miniaturizing the pixel circuit, only Vex corresponding to the waveform shown by the dotted line can be applied. In the configuration of the quench circuit of the present invention shown in FIG. 8(b), the first resistive element 202 and the second resistive element 221 are connected in series to the APD 201. In this case, the only parasitic capacitance component directly added to the cathode terminal is Cpd, and Cro is added via the second resistive element 221. As in FIG. 8(a), the signal amplitude of the cathode potential VC' is approximately equal to Vex. On the other hand, due to the resistance voltage division effect of the series resistor and the low-pass filter effect of the first resistive element 221 and the parasitic capacitance Cro, the signal amplitude at the potential VC of the terminal connected to the subsequent circuit is smaller than Vex. In particular, by setting the resistance value of the second resistive element 221 to be equal to or greater than the resistance value of the first resistive element 202, the resistive voltage division effect can be enhanced, and the occurrence of dielectric breakdown can be suppressed without using a high-voltage thick oxide film transistor in the pixel circuit.Specifically, the resistance value of the second resistive element 221 is set to be equal to or greater than the resistance value of the first resistive element 202. More preferably, the voltage division ratio is set 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. This makes it easy to reduce the area of ​​the pixel circuit even if Vex is increased, making it possible to achieve both high performance and miniaturization of the pixel.

[0065] In addition, of the two pixels shown in Figures 6 and 7, the first resistor element 202 connected to the first avalanche photodiode on the left and the first resistor element 202 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 elements 202 are formed on the same plane parallel to the surface of the first semiconductor layer. It can also be said that the first resistor elements 202 are provided in the same wiring layer in the wiring structure.

[0066] Another resistive element may be provided between the APD 201 and the power supply VL to control the avalanche multiplication current. In this case, the resistive voltage division effect due to the series resistor can be enhanced. In addition, in the present embodiment, the sensor configuration in which the sensor substrate 11 and the circuit substrate 21 are laminated has been described, but the sensor substrate 11 may be provided with circuits such as the signal processing portion 103, and the photoelectric conversion element may be configured only with the sensor substrate 11.

[0067] Second embodiment A photoelectric conversion device according to the second embodiment will be described with reference to Figs. 9 and 10. The parts common to the first embodiment will be omitted, and mainly the parts different from the first embodiment will be described. In this embodiment, the resistive element 332 is formed closer to the circuit board 21 than the cathode wiring 331A and the anode wiring 331B. By adopting a positional relationship in which a wiring part is formed between the sensor substrate 11 and the resistive element 332, the wiring part electrostatically shields the influence of the change in the potential of the resistive element 332, so that the influence on the APD formed on the sensor substrate 11 can be suppressed. This makes it possible to suppress the electric field concentration and the potential fluctuation near the substrate surface of the APD, and to suppress the increase in DCR.

[0068] 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). In this embodiment, the wiring portion 333A is not directly connected to the portion where the cathode wiring 331A and the resistive element 332 are connected. That is, the resistive element 332 and the wiring portion 333A overlap in a planar view, but the wiring connecting the resistive element 332 and the wiring portion 333A does not overlap with the resistive element 332 or the wiring portion 333A in a planar view.

[0069] 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.

[0070] FIG. 10(a) is equivalent to FIG. 7(a) according to the first embodiment.

[0071] 10(b), the resistive element 332 is formed in a fine line pattern and is electrically connected to the cathode wiring 331A and the power supply wiring 333B via a contact plug and a wiring layer. A contact plug 335 is formed on the middle part of the resistive element 332 and is electrically connected to the wiring part 333A. The wiring part 333A is electrically connected to the signal processing part 103 arranged on the circuit board 21 via a connection wiring provided for each pixel. In this embodiment, it is preferable that the formation temperature of the resistive element 332 is lower than the melting point of the material used for the wiring part, and it is preferable to use, for example, amorphous silicon, an inorganic transparent electrode, a metal thin film material, a ceramic material, an organic material, or the like.

[0072] (Third embodiment) A photoelectric conversion device according to the third embodiment will be described with reference to FIG.

[0073] The following description will omit the parts common to the first and second embodiments, and will mainly describe the parts different from the first embodiment. In this embodiment, a configuration for shortening the Dead time of the APD will be described.

[0074] FIG. 11 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. Unlike the first embodiment, there is no effect of reducing the signal amplitude by resistive voltage division, but 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 makes it easy to reduce the area of ​​the pixel circuit even when Vex is increased, making it possible to achieve both high performance and miniaturization of the pixel. Furthermore, since the resistive element 202 is the only one connected in series to the APD 201, it is easy to shorten the Dead Time.

[0075] 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.

[0076] (Fourth embodiment) A photoelectric conversion device according to the fourth embodiment will be described with reference to FIG.

[0077] The following description will omit the parts common to the first, second and third embodiments, and will mainly focus on the parts different from the first embodiment. In this embodiment, a configuration for shortening the dead time defined by the processing circuit will be described.

[0078] 12 is an example of a block diagram including an equivalent circuit of a pixel unit of a photoelectric conversion device according to the fourth embodiment. In this embodiment, a capacitive element 231 and a resistive element 223 are provided between a second resistive element 221 and a waveform shaping unit 210. Unlike the first embodiment, the capacitive element 231 functions as a high-pass filter, so that a pulse shorter than the signal waveform of VC is input to the waveform shaping unit 210. This makes it possible to shorten the ON period of a pulse input to a downstream processing circuit including a pixel circuit, and makes it easy to shorten the Dead time defined by the processing circuit.

[0079] Note that a transistor may be used instead of the resistive element 223 to define the reference potential of the input terminal of the waveform shaping section 210. Also, a capacitive element 231 may be provided between the resistive element 222 and the waveform shaping section 210 of the third embodiment or in front of the resistive element 222.

[0080] Fifth embodiment A photoelectric conversion device according to the fifth embodiment will be described with reference to FIG.

[0081] The following description will omit the parts common to the first, second, third and fourth embodiments, and will focus mainly on the parts different from the first embodiment. In this embodiment, a configuration will be described that suppresses signal detection loss by performing a high-speed recharge operation at a desired timing.

[0082] 13 is an example of a block diagram including an equivalent circuit of a pixel unit of a photoelectric conversion device according to the fifth embodiment. In this embodiment, a switch element 241 is added to the input terminal of a waveform shaping unit 210. A control pulse is input from outside the pixel to a gate terminal of the switch element 241, thereby returning the potential of VC to VH at a desired timing and recharging the APD 201 at high speed. This makes it possible to return the APD 201 regardless of whether a photon signal was detected at the immediately preceding timing, thereby suppressing signal detection loss.

[0083] Instead of inputting a control pulse from outside the pixel to the gate terminal of the switch element 241, an active recharge type configuration may be used in which the output of the circuitry following the waveform shaping unit 210 is fed back and input.

[0084] (Modification of the fifth embodiment) A photoelectric conversion device according to a modified example of the fifth embodiment will be described with reference to FIG.

[0085] The parts common to the first, second, third, fourth and fifth embodiments will be omitted, and the following mainly describes the parts different from the fifth embodiment. In this embodiment, the configuration of a pixel capable of switching the operation mode according to the scene or purpose of use will be described.

[0086] FIG. 14 is an example of a block diagram including an equivalent circuit of a pixel unit of a photoelectric conversion device according to a modification of the fifth embodiment. In this embodiment, a switch element 242 is provided between the first resistor element 202 and a power supply VH. When an H level is input to the gate terminal of the switch element 241 to turn the switch OFF and an L level is input to the gate terminal of the switch element 242 to turn the switch ON, the circuit configuration is the same as that of the first embodiment. When an H level is input to the gate terminal of the switch element 242 to turn the switch OFF and an L level is input to the gate terminal of the switch element 241 to turn the switch ON, a resistor voltage division ratio different from the above drive can be selected, and the signal amplitude and Dead time can be adjusted. When an H level is input to the gate terminal of the switch element 242 to turn the switch OFF and a periodic pulse signal is input to the gate of the switch element 241, a clock recharge type drive can be realized, and low power consumption operation can be achieved.

[0087] In this manner, in this embodiment, it is possible to shorten the dead time and suppress power consumption according to the scene and purpose of use.

[0088] Sixth 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] Seventh 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] Eighth 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] Ninth 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] (Tenth 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 sixth and seventh 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 eighth embodiment, the endoscope shown in the ninth embodiment, and the smart glasses shown in the tenth 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 and a first wiring structure stacked on the first semiconductor layer, and a second substrate including a second semiconductor layer and a second wiring structure stacked on the second semiconductor layer, the photoelectric conversion device comprising: an avalanche photodiode disposed on the first semiconductor layer; a first resistive element disposed on the first substrate and connected to the avalanche photodiode; a waveform shaping unit disposed on the second semiconductor layer for shaping an output signal of the avalanche photodiode; and a second resistive element disposed on the first substrate and connected to the avalanche photodiode, the waveform shaping unit, and the first resistive element.

[0137] (Configuration 2) The photoelectric conversion device according to configuration 1, wherein the second resistive element is connected between the avalanche photodiode and the first resistive element.

[0138] (Configuration 3) The photoelectric conversion device according to configuration 1, wherein the second resistive element is connected between the first resistive element and the waveform shaping section.

[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 the first resistive element connected to a first avalanche photodiode among the plurality of avalanche photodiodes and the first resistive element connected to a second avalanche photodiode are provided in 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 at least one of the first resistance element and the second resistance element contains polysilicon or amorphous silicon.

[0141] (Configuration 6) The photoelectric conversion device according to any one of Configurations 1 to 5, wherein at least one of the first resistive element and the second 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 at least one of the first resistance element and the second resistance element includes a ceramic material.

[0143] (Configuration 8) The photoelectric conversion device according to any one of Configurations 1 to 7, wherein at least one of the first resistance element and the second resistance element contains an organic material.

[0144] (Configuration 9) A photoelectric conversion device described in any one of configurations 1 to 8, characterized in that the ratio of the shortest side to the longest side of at least one of the first resistance element and the second resistance element is 10 or more.

[0145] (Configuration 10) A photoelectric conversion device described in any one of configurations 1 to 9, characterized in that at least one of the first resistance element and the second resistance element is composed of a material having a higher resistivity than the main material of the wiring.

[0146] (Configuration 11) A photoelectric conversion device described in any one of configurations 1 to 10, characterized in that at least one of the first resistive element and the second 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 at least one of the first resistive element and the second resistive element overlaps with the cathode of the avalanche photodiode in a planar 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) A photoelectric conversion device according to any one of configurations 1 to 13, characterized in that at least one of the first resistive element and the second resistive element is connected to the waveform shaping section via a capacitive element.

[0150] (Configuration 15) A photoelectric conversion device described in any one of configurations 1 to 14, characterized in that at least one of the first resistance element and the second resistance element extends in the direction in which the first semiconductor layer and the second semiconductor layer are stacked.

[0151] (Configuration 16) The photoelectric conversion device according to any one of configurations 1 to 15, wherein two power supply wirings for supplying voltages to the cathode and anode of the avalanche photodiode, respectively, are disposed on the first substrate.

[0152] (Configuration 17) In the photoelectric conversion device according to any one of configurations 1 to 16, the resistance value of the second resistive element is equal to or greater than the resistance value of the first resistive element.

[0153] (Configuration 18) The photoelectric conversion device according to any one of configurations 1 to 17, wherein the first resistance element and the second resistance element are arranged in the same plane parallel to the surface of the first semiconductor layer.

[0154] (Configuration 19) In the photoelectric conversion device according to configuration 18, three or more contact plugs are connected to the first resistance element and the second resistance element.

[0155] (Configuration 20) The photoelectric conversion device according to configuration 18 or 19, wherein contact plugs are connected to both the upper and lower sides of the first resistance element and the second resistance element.

[0156] (Configuration 21) The photoelectric conversion device according to any one of configurations 1 to 20, further comprising a switch connected between the input terminal of the waveform shaping unit and a wiring for supplying a reference voltage.

[0157] (Configuration 22) A photoelectric conversion device described in any one of configurations 1 to 21, characterized in having a switch connected between a terminal of the first resistance element that is not connected to the waveform shaping section and a wiring that supplies a reference voltage.

[0158] (Configuration 23) The photoelectric conversion device according to any one of configurations 1 to 22, a signal processing unit that generates an image using a signal output from the photoelectric conversion device.

[0159] (Configuration 24) A moving object including the photoelectric conversion device according to any one of configurations 1 to 22, A control unit that controls the movement of the moving body using a signal output from the photoelectric conversion device. A moving object characterized by: [Explanation of symbols]

[0160] 100 Photoelectric conversion device 201 Avalanche photodiode 202 Resistance element 210 Waveform shaping section

Claims

1. A first substrate including a first semiconductor layer and a first wiring structure laminated on the first semiconductor layer, A second substrate including a second semiconductor layer and a second wiring structure laminated on the second semiconductor layer, A photoelectric conversion device having: An avalanche photodiode disposed in the first semiconductor layer, A first resistor element disposed on the first substrate and connected to the avalanche photodiode, A waveform shaping unit disposed in the second semiconductor layer for shaping an output signal of the avalanche photodiode, A second resistor element disposed on the first substrate and connected to the avalanche photodiode, the waveform shaping unit, and the first resistor element, The photoelectric conversion device, characterized in that three or more contact plugs are connected to the first resistor element and the second resistor element.

2. The photoelectric conversion device according to claim 1, wherein the second resistor element is connected between the avalanche photodiode and the first resistor element.

3. The photoelectric conversion device according to claim 1, wherein the second resistor element is connected between the first resistor element and the waveform shaping unit.

4. Having a plurality of the avalanche photodiodes, The photoelectric conversion device according to claim 1, wherein the first resistor element connected to a first avalanche photodiode among the plurality of avalanche photodiodes and the first resistor element connected to a second avalanche photodiode are provided in the same plane parallel to the surface of the first semiconductor layer.

5. The photoelectric conversion device according to claim 1, wherein at least one of the first resistor element and the second resistor element contains polysilicon or amorphous silicon.

6. The photoelectric conversion device according to claim 1, wherein at least one of the first resistance element and the second resistance element contains a metal thin film material.

7. The photoelectric conversion device according to claim 1, wherein at least one of the first resistance element and the second resistance element contains a ceramic material.

8. The photoelectric conversion device according to claim 1, wherein at least one of the first resistance element and the second resistance element contains an organic material.

9. The photoelectric conversion device according to claim 1, wherein the ratio of the shortest side to the longest side of at least one of the first resistance element and the second resistance element is 10 or more.

10. The photoelectric conversion device according to claim 1, wherein at least one of the first resistance element and the second resistance element is composed of a material having a higher resistivity than the main material of the wiring.

11. The photoelectric conversion device according to claim 1, wherein at least one of the first resistance element and the second resistance element is composed of a material having a higher resistivity than the main material of the via for supplying voltage to the avalanche photodiode.

12. The photoelectric conversion device according to claim 1, wherein at least one of the first resistance element and the second resistance element overlaps the cathode of the avalanche photodiode in plan view.

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

14. The photoelectric conversion device according to claim 1, wherein at least one of the first resistance element and the second resistance element and the waveform shaping unit are connected via a capacitance element.

15. At least one of the first resistance element and the second resistance element extends in a direction in which the first semiconductor layer and the second semiconductor layer are stacked. The photoelectric conversion device according to claim 2, characterized in that.

16. Two systems of power supply wirings for supplying voltages to the cathode and anode of the avalanche photodiode are arranged on the first substrate. The photoelectric conversion device according to claim 1, characterized in that.

17. The resistance value of the second resistance element is equal to or greater than the resistance value of the first resistance element. The photoelectric conversion device according to claim 1, characterized in that.

18. The first resistance element and the second resistance element are arranged in the same plane parallel to the surface of the first semiconductor layer. The photoelectric conversion device according to claim 1, characterized in that.

19. Contact plugs are connected to both the upper and lower sides of the first resistance element and the second resistance element. The photoelectric conversion device according to claim 18, characterized in that.

20. The photoelectric conversion device according to claim 1, characterized by having a switch connected between the input terminal of the waveform shaping unit and the wiring for supplying a reference voltage.

21. The photoelectric conversion device according to claim 1, characterized by having a switch connected between the terminal of the first resistance element that is not connected to the waveform shaping unit and the wiring for supplying a reference voltage.

22. A first substrate including a first semiconductor layer and a first wiring structure laminated on the first semiconductor layer, A second substrate including a second semiconductor layer and a second wiring structure laminated on the second semiconductor layer, A photoelectric conversion device having, An avalanche photodiode disposed on the first semiconductor layer, A first resistance element disposed on the first substrate and connected to the avalanche photodiode, A waveform shaping unit that is disposed on the second semiconductor layer and shapes the output signal of the avalanche photodiode. A second resistor element that is disposed on the first substrate and is connected to the avalanche photodiode, the waveform shaping unit, and the first resistor element. An optoelectronic conversion device, characterized in that it has a switch connected between a terminal of the first resistor element that is not connected to the waveform shaping unit and a wiring for supplying a reference voltage. **Claim 23** An optoelectronic conversion device according to claim 1, A signal processing unit that generates an image using a signal output by the optoelectronic conversion device. An optoelectronic conversion system characterized by having the same. **Claim 24** A moving body including the optoelectronic conversion device according to claim 1, A moving body characterized by having a control unit that controls the movement of the moving body using a signal output by the optoelectronic conversion device.

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