Photoelectric conversion device, photoelectric conversion system, mobile object, and equipment

Abstract

To provide a suitable pixel structure in a configuration in which a high-sensitivity pixel and a low-sensitivity pixel each include an avalanche photodiode.SOLUTION: A photoelectric conversion device according to the present invention has a first pixel including a first avalanche photodiode, a second pixel including a second avalanche photodiode, and a separation portion separating the first pixel and the second pixel, and in a planar view, the distance from the center of the first pixel to the separation portion is longer than the distance from the center of the second pixel to the separation portion.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a photoelectric conversion device, a photoelectric conversion system, a mobile object, and an instrument. [Background technology]

[0002] There is known a photoelectric conversion device that can detect weak light at the single photon level by utilizing avalanche multiplication. Patent Document 1 discloses a photoelectric conversion device in which a sensor chip on which a plurality of pixels are arranged and a circuit chip on which a circuit for performing signal processing is formed are both electrically connected in a stacked structure. It is also disclosed that avalanche photodiodes (APDs), in which electric charges undergo avalanche multiplication, are used for the pixels in the sensor chip of this photoelectric conversion device.

[0003] There is also known a technique of using high-sensitivity pixels and low-sensitivity pixels in order to expand the dynamic range, suppress flicker, etc. Patent Document 2 discloses a light receiving device in which APDs are used for both the high-sensitivity pixels and the low-sensitivity pixels. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2017 / 0186798 [Patent Document 2] JP 2022-168741 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a configuration in which each of the high-sensitivity pixel and the low-sensitivity pixel includes an APD, there is room for consideration of a suitable pixel structure.

[0006] An object of the present invention is to provide a suitable pixel structure in a configuration in which each of the high-sensitivity pixel and the low-sensitivity pixel includes an avalanche photodiode. [Means for solving the problem]

[0007] A first aspect of the present invention is a photoelectric conversion device having a first pixel including a first avalanche photodiode, a second pixel including a second avalanche photodiode, and a separation portion separating the first pixel and the second pixel, wherein, in a planar view, the distance from the center of the first pixel to the separation portion is longer than the distance from the center of the second pixel to the separation portion.

[0008] A second aspect of the present invention is a photoelectric conversion device having a first pixel including a first avalanche photodiode and a second pixel including a second avalanche photodiode, and being configured to suppress leakage of light from the first pixel to the second pixel more strongly than leakage of light from the second pixel to the first pixel.

[0009] A third aspect of the present invention is a photoelectric conversion device having a first pixel including a first avalanche photodiode and a second pixel including a second avalanche photodiode, wherein the first pixel has a trench that is not provided in the second pixel.

[0010] A fourth aspect of the present invention is a photoelectric conversion system comprising the above-mentioned photoelectric conversion device and a signal processing unit that generates an image using a signal output by the photoelectric conversion device.

[0011] A fifth aspect of the present invention is a moving body comprising the above-mentioned photoelectric conversion device, 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.

[0012] A sixth aspect of the present invention is an apparatus comprising the above-mentioned photoelectric conversion device, and at least one of an optical device corresponding to the photoelectric conversion device, a control device controlling the photoelectric conversion device, a processing device processing a signal output from the photoelectric conversion device, a display device displaying information obtained by the photoelectric conversion device, a memory device storing information obtained by the photoelectric conversion device, and a mechanical device operating based on information obtained by the photoelectric conversion device. Effect of the Invention

[0013] According to the present invention, in a configuration in which the high-sensitivity pixel and the low-sensitivity pixel each include an avalanche photodiode, a suitable pixel structure can be provided. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram of a photoelectric conversion device according to an embodiment. [Diagram 2] 2 is a schematic diagram of a pixel 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] 3 is a schematic diagram showing driving of a pixel circuit of a photoelectric conversion device according to an embodiment. FIG. [Figure 6] 1A and 1B are a plan view and a cross-sectional view of a photoelectric conversion device according to a first embodiment. [Figure 7] 1A and 1B are a plan view and a cross-sectional view of a photoelectric conversion device serving as a comparative example. [Figure 8] FIG. 4 is a cross-sectional view of a modified example of the photoelectric conversion device according to the first embodiment. [Figure 9] 1A and 1B are a plan view and a cross-sectional view of a photoelectric conversion device according to a second embodiment. [Figure 10] FIG. 11 is a plan view of a photoelectric conversion device according to a third embodiment. [Figure 11] FIG. 11 is a cross-sectional view of a photoelectric conversion device according to a third embodiment. [Figure 12] FIG. 13 is a plan view of a photoelectric conversion device according to a fourth embodiment. [Figure 13] FIG. 11 is a cross-sectional view of a photoelectric conversion device according to a fourth embodiment. [Figure 14] FIG. 13 is a plan view of a photoelectric conversion device according to a fifth embodiment. [Figure 15] FIG. 11 is a cross-sectional view of a photoelectric conversion device according to a fifth embodiment. [Figure 16] FIG. 13 is a plan view of a photoelectric conversion device according to a sixth embodiment. [Figure 17] FIG. 13 is a cross-sectional view of a photoelectric conversion device according to a sixth embodiment. [Figure 18] FIG. 13 is a plan view of a photoelectric conversion device according to a seventh embodiment. [Figure 19] FIG. 13 is a cross-sectional view of a photoelectric conversion device according to a seventh embodiment. [Figure 20] FIG. 13 is a plan view of a modified example of the photoelectric conversion device according to the seventh embodiment. [Figure 21] FIG. 13 is a plan view of a photoelectric conversion device according to an eighth embodiment. [Figure 22] FIG. 13 is a cross-sectional view of a photoelectric conversion device according to an eighth embodiment. [Diagram 23] FIG. 13 is a plan view of a photoelectric conversion device according to a ninth embodiment. [Figure 24] FIG. 13 is a cross-sectional view of a photoelectric conversion device according to a ninth embodiment. [Diagram 25] FIG. 23 is a diagram illustrating a photoelectric conversion system according to a tenth embodiment. [Figure 26] FIG. 23 is a diagram illustrating a photoelectric conversion system and a moving object according to an eleventh embodiment. [Figure 27] FIG. 23 is a diagram illustrating a range image sensor according to a twelfth embodiment. [Figure 28] FIG. 23 is a diagram illustrating an endoscopic surgery system according to a thirteenth embodiment. [Figure 29] FIG. 23 is a diagram illustrating smart glasses according to a fourteenth embodiment. [Diagram 30] FIG. 23 is a diagram illustrating an electronic device according to a fifteenth embodiment. [Diagram 31]FIG. 23 is a diagram for explaining an X-ray CT apparatus according to a sixteenth embodiment. [Diagram 32] FIG. 23 is a diagram illustrating an apparatus according to a seventeenth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The following embodiments are intended to embody the technical concept of the present invention and do not limit the present invention. The drawings are not intended to be limiting. The sizes and positional relationships of components shown in the drawings may be exaggerated for clarity. In the following description, the same components are designated by the same reference numerals and the description thereof may be omitted.

[0016] 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.

[0017] 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 view from 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.

[0018] The semiconductor layer has a first surface and a second surface, which is the surface opposite to the first surface and on which light is incident. In this specification, the depth direction is the direction from the first surface to the second surface of the semiconductor layer on which the avalanche photodiode (APD) is arranged. Hereinafter, the "first surface" may be referred to as the "front surface" and the "second surface" may be referred to as the "rear surface." The "depth" of a point or a region in the semiconductor layer means the distance from the first surface (front surface) of the point or region. When there is a point (or region) Z1 whose distance (depth) from the first surface is d1 and a point (or region) Z2 whose distance (depth) from the first surface is d2, and d1>d2, it may be expressed as "Z1 is deeper than Z2" or "Z2 is shallower than Z1." Also, when there is a point (or region) Z3 whose distance (depth) from the first surface is d3, and d1>d3>d2 holds, it can be expressed as "Z3 is at a depth between Z1 and Z2" or "Z3 is between Z1 and Z2 in the depth direction."

[0019] In the following description, the anode of the avalanche photodiode (APD) is set to a fixed potential, and a signal is taken 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 from 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 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 from 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.

[0020] 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.

[0021] In addition, in the following embodiments, the connection between elements of a circuit may be described. In this case, even if another element is interposed between the elements of interest, the elements of interest are treated as being electrically connected to each other unless otherwise specified. For example, assume that element A is connected to one node of a capacitive element C having multiple nodes, and element B is connected to the other node. Even in such a case, elements A and B are treated as being electrically connected to each other unless otherwise specified. Also, when elements are connected to each other without going through another element, they may be described as being directly connected. In the above example, between element A and capacitive element C, When no other elements are provided between element A and capacitive element C, it can be said that element A and capacitive element C are directly connected.

[0022] Metallic members such as wiring and pads described in this specification may be composed of a single metal element or may be a mixture (alloy). For example, wiring described as copper wiring may be composed of a single copper element or may be composed mainly of copper and further contain other components. Also, for example, pads connected to external terminals may be composed of a single aluminum element or may be composed mainly of aluminum and further contain other components. The copper wiring and aluminum pads shown here are examples and can be changed to various metals.

[0023] Moreover, the wiring and pads shown here are one example of metal members used in a photoelectric conversion device, and the present invention can also be applied to other metal members.

[0024] In the following embodiments, an image pickup device will be mainly described as an example of a photoelectric conversion device. However, each embodiment is not limited to an image pickup device, and can be applied to other examples of photoelectric conversion devices. For example, a distance measuring device (a device for measuring distance using focus detection or TOF (Time Of Flight)) or a photometric device (a device for measuring the amount of incident light) may be used.

[0025] A configuration common to each embodiment of a photoelectric conversion device and a driving method thereof according to the present invention will be described with reference to FIGS. 1 to 5. FIG.

[0026] FIG. 1 is a diagram showing a configuration of a photoelectric conversion device 100 according to an embodiment of the present invention. In the following, a case where the photoelectric conversion device 100 is a stacked type photoelectric conversion device will be described as an example. That is, a photoelectric conversion device configured by stacking and electrically connecting two substrates, a sensor substrate 11 and a circuit substrate 21, will be described as an example. However, the photoelectric conversion device is not limited to this. For example, the photoelectric conversion device may be a photoelectric conversion device in which the configuration included in the sensor substrate 11 and the configuration included in the circuit substrate 21 are arranged on a common semiconductor layer, as described below. In the following, a photoelectric conversion device in which the configuration included in the sensor substrate 11 and the configuration included in the circuit substrate 21 are arranged on a common semiconductor layer will also be referred to as a non-stacked photoelectric conversion device.

[0027] The sensor substrate 11 has a first semiconductor layer having photoelectric conversion elements 102 described later, and a first wiring structure. The circuit substrate 21 has a second semiconductor layer having circuits such as a signal processing unit 103 described later, and a second wiring structure. The photoelectric conversion device 100 is configured by laminating the second semiconductor layer, the second wiring structure, the first wiring structure, and the first semiconductor layer in this order.

[0028] 1 illustrates a back-illuminated photoelectric conversion device in which light is incident from the second surface (rear surface) and a circuit board 21 is disposed on the first surface (front surface) that is the surface opposite the second surface. In the case of a non-stacked photoelectric conversion device, the surface on which the transistors of the signal processing circuit are disposed is referred to as the first surface. In the case of a front-illuminated photoelectric conversion device, the front surface is the second surface (light incident surface) and the back surface is the first surface.

[0029] In the following, the sensor substrate 11 and the circuit substrate 21 will be 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 each chip may be stacked and bonded after being chipped.

[0030] 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.

[0031] 2 is a layout diagram of the sensor substrate 11. Pixels 101, each having a photoelectric conversion element 102 including an avalanche photodiode (APD), are arranged two-dimensionally to form a pixel region 12.

[0032] The pixel 101 is typically a pixel for forming an image, but when used for TOF (Time of Flight), it does not necessarily have to form an image. That is, the pixel 101 may be a pixel for measuring the time when light arrives and the amount of light.

[0033] 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, signal lines 113, a vertical scanning circuit unit 110, drive lines 116, and an output circuit 114.

[0034] 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.

[0035] 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 via a driving line 116. The vertical scanning circuit section 110 uses logic circuits such as a shift register and an address decoder.

[0036] The control pulse generating unit 115 has a signal generating unit 215 that generates a control signal P_CLK for a switch, which will be described later. The signal generating unit 215 generates a pulse signal for controlling the switch, as will be described later. For example, as shown in FIG. 4(A), the signal generating unit 215 may generate a control signal P_CLK in common for a plurality of pixels in the pixel region 12, or as shown in FIG. 4(B), the control signal P_CLK may be generated for each pixel. When the pulse signal P_CLK is generated in common, at least one of the period, the number of pulses, and the pulse width of the signal P_EXP pulse signal for controlling the exposure period is generated in common in correspondence with the exposure period. When the control signal P_CLK is controlled for each pixel, a signal can be generated using both the input signal P_CLK_IN output from the control pulse generating unit 115 and the signal P_EXP for controlling the exposure period. For example, the control pulse generating unit 115 preferably has a frequency dividing circuit. This allows simple control and reduces an increase in the number of elements.

[0037] The signal output from the photoelectric conversion element 102 of each 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.

[0038] 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.

[0039] 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.

[0040] 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 .

[0041] 2, the pixels 101 may be arranged one-dimensionally in the pixel region 12. The function of the signal processing unit 103 does not necessarily need to be provided for each pixel 101, and for example, one signal processing unit 103 may be shared by a plurality of pixels 101 to perform signal processing sequentially.

[0042] Figures 4(A) and 4(B) are examples of block diagrams including the equivalent circuits of Figures 2 and 3. Figure 4(A) is an example in which the signal generating unit 215 is provided in common to a plurality of pixels, and Figure 4(B) is an example in which the control signal P_CLK can be controlled for each pixel. Figure 4(A) will be explained.

[0043] In FIG. 4A, 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.

[0044] The APD 201 generates charge pairs according to the incident light by photoelectric conversion. A voltage VL (first voltage) is supplied to the anode of the APD 201. A voltage VH (second voltage) higher than the voltage VL supplied to the anode is supplied to the cathode of the APD 201. A reverse bias voltage that causes the APD 201 to perform avalanche multiplication is supplied to the anode and cathode. With such a voltage supplied, the charges generated by the incident light undergo avalanche multiplication, generating an avalanche current.

[0045] 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. An APD operated in Geiger mode is called a SPAD. For example, the voltage VL (first voltage) is -30V, and the voltage VH (second voltage) is 1V. The APD201 may be operated in either linear mode or Geiger mode. In the case of a SPAD, the potential difference is greater than in a linear mode APD, and the effect of withstanding voltage becomes more pronounced.

[0046] The switch 202 is connected to a power supply line to which a drive voltage VH is supplied and to the APD 201. The switch 202 is connected to one of the anode and cathode nodes of the APD 201. The switch 202 switches the potential difference between the anode and cathode of the APD 201 between a first potential difference that causes avalanche multiplication and a second potential difference that does not cause avalanche multiplication. Hereinafter, switching from the second potential difference to the first potential difference is also referred to as turning on the switch 202, and switching from the first potential difference to the second potential difference is also referred to as turning off the switch 202. The switch 202 functions as a quenching element. The switch 202 functions as a load circuit (quenching circuit) during signal multiplication by avalanche multiplication, and has a function of suppressing avalanche multiplication by suppressing the voltage supplied to the APD 201 (quenching operation). The switch 202 also has a function of returning the voltage supplied to the APD 201 to the drive voltage VH by passing a current equivalent to the voltage drop caused by the quench operation (recharge operation). In other words, the switch 202 functions as a control circuit for controlling the occurrence of avalanche multiplication in the APD 201.

[0047] The switch 202 can be configured, for example, by a MOS transistor. A control signal P_CLK for the switch 202, which is supplied from the signal generating unit 215, is applied to a gate electrode of the MOS transistor that configures the switch 202. In this embodiment, the on / off of the switch 202 is controlled by controlling the voltage applied to the gate electrode of the switch 202.

[0048] The signal processing section 103 has a waveform shaping section 210, a counter circuit 211, and a selection circuit 212. In this specification, it is sufficient that the signal processing section 103 has at least one of the waveform shaping section 210, the counter circuit 211, and the selection circuit 212.

[0049] The waveform shaping unit 210 shapes the potential change of the cathode of the APD 201 obtained when a photon is detected, and outputs a pulse signal. The node of is nodeB. The waveform shaping unit 210 changes the output potential from the node nodeB depending on whether the input potential to the node nodeA is equal to or higher than a predetermined value or lower. For example, in FIG. 5, when the input potential to the node nodeA becomes a high potential equal to or higher than the judgment threshold, the output potential from the node nodeB becomes a low level. When the input potential to the node nodeA becomes a low potential below the judgment threshold, the output potential from the node nodeB becomes a high level. For example, an inverter circuit is used as the waveform shaping unit 210. In FIG. 4(A), an example is shown in which one inverter is used as the waveform shaping unit 210, but a circuit in which multiple inverters are connected in series, or other circuits having a waveform shaping effect may be used.

[0050] It is possible to perform a quench operation and a recharge operation using the switch 202 according to the avalanche multiplication in the APD 201, but depending on the timing of photon detection, the charge generated in the APD 201 may not be determined as an output signal. For example, assume that avalanche multiplication occurs in the APD 201, the node nodeA becomes low level, and a recharge operation is performed. In general, the decision threshold of the waveform shaping unit 210 is set to a potential higher than the potential difference at which avalanche multiplication occurs in the APD 201. When a photon is incident on the APD 201 when the potential of the node nodeA is lower than the decision threshold due to the recharge operation and the potential is such that avalanche multiplication is possible in the APD 201, avalanche multiplication occurs in the APD 201 and the voltage of the nodeA drops. In other words, since the potential of the nodeA drops at a voltage lower than the decision threshold, no potential change occurs across the decision threshold, and the output potential from the node nodeB does not change. Therefore, even though avalanche multiplication occurs, the photon detection is not determined as a signal. Particularly under high illuminance, photons enter the APD 201 continuously in a short period of time, making it difficult to determine the incident light as a signal. As a result, even under high illuminance, the actual number of incident photons and the output signal tend to diverge.

[0051] In contrast, by applying a control signal P_CLK to the switch 202 to switch the switch 202 between an on state and an off state, it is possible to determine a signal even when photons continuously enter the APD 201 in a short period of time. In FIG. 5, an example is described in which the control signal P_CLK is a pulse signal with a repetitive cycle. In other words, in FIG. 5, a form is described in which the switch 202 is switched on and off at a predetermined clock frequency. However, the effect of suppressing an increase in power consumption of the photoelectric conversion device 100 can be obtained even if the pulse signal is not a signal with a repetitive cycle.

[0052] The counter circuit 211 counts the pulse signal output from the waveform shaping unit 210 and holds the count value. When a control pulse pRES is supplied via a drive line 213, the signal held in the counter circuit 211 is reset.

[0053] A control pulse pSEL is supplied to the selection circuit 212 from the vertical scanning circuit unit 110 in Fig. 3 via the drive line 214 in Fig. 4(A), and switches between electrical connection and non-connection between the counter circuit 211 and the signal line 113. The selection circuit 212 includes, for example, a buffer circuit for outputting a signal.

[0054] The electrical connection may be switched by disposing a switch such as a transistor between the switch 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.

[0055] In this embodiment, a configuration using the counter circuit 211 has been shown. However, in place of the counter circuit 211, a photoelectric conversion device that acquires the pulse detection timing using a time to digital converter (hereinafter, TDC) or a memory may be used. The waveform shaping unit 210 may be the pixel shift register 100. At this time, the generation timing of the pulse signal output from the waveform shaping unit 210 is converted into a digital signal by the TDC. In order 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. 3 via a drive line. The TDC acquires, as a digital signal, a value obtained by converting the input timing of the signal output from each pixel into a relative time based on the control pulse pREF.

[0056] FIG. 5 is a diagram showing a schematic diagram of the relationship between the control signal P_CLK of the switch, the potential of the node nodeA, the potential of the node nodeB, and the output signal. In this embodiment, when the control signal P_CLK is at a high level, the drive voltage VH is not easily supplied to the APD 201, and when the control signal P_CLK is at a low level, the drive voltage VH is supplied to the APD 201. The high level of the control signal P_CLK is, for example, 1V, and the low level of the control signal P_CLK is, for example, 0V. When the control signal P_CLK is at a high level, the switch is turned off, and when the control signal P_CLK is at a low level, the switch is turned on. The resistance value of the switch when the control signal P_CLK is at a high level is higher than the resistance value of the switch when the control signal P_CLK is at a low level. When the control signal P_CLK is at a high level, even if avalanche multiplication occurs in the APD 201, a recharge operation is not easily performed, so the potential supplied to the APD 201 is a potential equal to or lower than the breakdown voltage of the APD 201. Therefore, the avalanche multiplication operation in the APD 201 is stopped.

[0057] As shown in Fig. 4(A), it is preferable to configure the switch 202 with one transistor, and to perform the quenching operation and the recharge operation with one transistor. This makes it possible to reduce the number of circuits compared to the case where the quenching operation and the recharge operation are performed with different circuit elements. In particular, when each pixel has a counter circuit and the SPAD signal is read out for each pixel, it is preferable to reduce the circuit area used for the switch in order to place the counter circuit, and the effect of configuring the switch 202 with one transistor becomes significant.

[0058] At time t1, the control signal P_CLK changes from high level to low level, the switch is turned on, and the recharge operation of the APD 201 is started. This causes the potential of the cathode of the APD 201 to transition to high level. Then, the potential difference between the potentials applied to the anode and cathode of the APD 201 becomes a state in which avalanche multiplication is possible. The potential of the cathode is the same as that of the node nodeA. Therefore, when the potential of the cathode transitions from low level to high level, the potential of the node nodeA becomes equal to or higher than the judgment threshold at time t2. At this time, the pulse signal output from the node nodeB is inverted and goes from high level to low level. After that, the potential difference of the drive voltage VH-drive voltage VL is applied to the APD 201. The control signal P_CLK becomes high level, and the switch is turned off.

[0059] Next, at time t3, when a photon is incident on the APD 201, avalanche multiplication occurs in the APD 201, and the voltage of the cathode drops. That is, the voltage of the node nodeA drops. When the amount of voltage drop becomes larger and the voltage difference applied to the APD 201 becomes smaller, the avalanche multiplication of the APD 201 stops as at time t2, and the voltage level of the node nodeA does not drop by more than a certain value. When the voltage of the node nodeA becomes lower than the decision threshold while the voltage of the node nodeA is dropping, the voltage of the node nodeB goes from low level to high level. That is, the part of the output waveform at the node nodeA that exceeds the decision threshold is waveform-shaped by the waveform shaping unit 210 and output as a signal at the nodeB. Then, it is counted by the counter circuit, and the count value of the counter signal output from the counter circuit increases by 1 LSB.

[0060] Between time t3 and time t4, photons are incident on the APD 201, but the switch is in the off state. Since the voltage applied to the APD 201 is not a potential difference that allows avalanche multiplication, the voltage level of the node A does not exceed the decision threshold.

[0061] At time t4, the control signal P_CLK changes from high to low, and the switch is turned on. As a result, a current flows to node A to compensate for the voltage drop from the drive voltage VH, and the voltage of node A transitions to its original voltage level. At this time, the voltage of node A becomes equal to or higher than the decision threshold at time t5, so the pulse signal of node B is inverted and goes from high to low.

[0062] At time t6, node A is stabilized to the original voltage level, and the control signal P_CLK goes from low to high. Therefore, the switch is turned off. After this, the potentials of the nodes and signal lines change in response to the control signal P_CLK and the incidence of photons, as described from time t1 to time t6.

[0063] The photoelectric conversion devices of the respective embodiments will be described below.

[0064] (First embodiment) Figures 6(A) and 6(B) show the structure of the sensor substrate 11 of the photoelectric conversion device according to the first embodiment. Figure 6(A) is a plan view showing the configuration of the pixel region 12, and shows a schematic view of the semiconductor layer 300 of the sensor substrate 11 as viewed from the first surface side. Figure 6(B) is a cross-sectional view taken along line AA in Figure 6(A).

[0065] As shown in Fig. 6(A), a plurality of APDs 201 are arranged on the semiconductor layer 300. For convenience of illustration, only three APDs 201 arranged in one row and three columns are shown in Fig. 6(A), but in an actual product, for example, hundreds of thousands to millions of APDs 201 are formed in a two-dimensional array. One APD 201 corresponds to one pixel.

[0066] The semiconductor layer 300 is provided with an isolation section 330, which is an isolation structure for reducing optical crosstalk (light leakage) between adjacent APDs 201, 201. Although the isolation section 330 is drawn by a line in FIG. 6A, the isolation section 330 actually has a thickness. The APDs 201 are disposed in each of the sections divided by the isolation section 330. In this manner, a plurality of pixels are isolated by the isolation section 330. The section corresponding to one pixel has a substantially square shape in a plan view. In other words, the isolation section 330 surrounds one pixel with a substantially rectangular shape in a plan view. The contact plug 326 of the cathode wiring formed in the wiring structure 320 is disposed substantially at the center of the pixel (section), and the contact plug 324 of the anode wiring is disposed at the edge of the pixel.

[0067] As shown in FIG. 6B, the sensor substrate 11 has a structure in which a semiconductor layer 300 and a wiring structure 320 are laminated. The surface of the semiconductor layer 300 facing the wiring structure 320 is called the first surface, and the surface opposite to the first surface is called the second surface. The semiconductor layer 300 is made of, for example, silicon. A fixed charge film 310, an insulating film 311, a planarization film 312, and the like are laminated in this order on the second surface of the semiconductor layer 300, and a microlens 313 corresponding to each pixel is further provided above them. That is, the photoelectric conversion device according to the first embodiment has a so-called back-illuminated structure in which light is incident on the semiconductor layer 300 from the second surface side. The second surface may also be called a light incident surface. In addition, the following structure can be applied to the light incident surface. For example, an uneven structure such as at least one or more recesses or protrusions is arranged on the second surface, which is the light incident surface. The uneven structure is formed by silicon constituting the semiconductor layer 300 and other members. For example, an insulator such as a silicon oxide film, a silicon oxynitride film, or a silicon nitride film is disposed in a recess provided in the semiconductor layer 300. An interface having a refractive index difference that is not parallel to the second surface is formed. With this configuration, incident light is diffracted, which can improve sensitivity to light in the infrared region. can.

[0068] The fixed charge film 310 is made of a dielectric having a negative fixed charge and is disposed over the entire second surface of the semiconductor layer 300. The material of the fixed charge film 310 is selected from, for example, hafnium oxide, aluminum oxide, zirconium oxide, titanium oxide, tantalum oxide, and ruthenium oxide, and among them, aluminum oxide or hafnium oxide is preferable. The fixed charge film 310 may be configured to be composed of multiple layers. The insulating film 311 is disposed over the entire second surface on the fixed charge film 310. For example, a silicon oxide film, a silicon oxynitride film, or a silicon nitride film can be suitably used as the insulating film 311. The insulating film 311 may be configured to be composed of multiple layers. Although not shown, in addition to the planarization film 312, a filter layer such as a color filter or an infrared light cut filter may be provided on the second surface side of the semiconductor layer 300.

[0069] Wiring structure 320 is a structure in which wiring 321, anode wiring contact plug 324, cathode wiring contact plug 326, etc. are arranged in insulating layer 329. The lower surface of wiring structure 320 (the surface opposite to semiconductor layer 300) is a bonding surface with circuit board 21, and a plurality of bonding portions 328 (metal bonding) are provided on the bonding surface.

[0070] The semiconductor layer 300 has a first semiconductor region 301, a second semiconductor region 302, a third semiconductor region 303, a fourth semiconductor region 304, a fifth semiconductor region 305, a sixth semiconductor region 306, a seventh semiconductor region 307, and an eighth semiconductor region 308. Each semiconductor region is a region to which impurities are added by ion implantation, or a region to which impurities are added during the preparation and epitaxial growth of a semiconductor substrate. Here, the first semiconductor region 301, the fifth semiconductor region 305, the sixth semiconductor region 306, and the seventh semiconductor region 307 are semiconductor regions of a first conductivity type (N type in the first embodiment). The second semiconductor region 302, the third semiconductor region 303, the fourth semiconductor region 304, and the eighth semiconductor region 308 are semiconductor regions of a second conductivity type (P type in the first embodiment).

[0071] The first semiconductor region 301 is a semiconductor region of a first conductivity type (N type in the first embodiment) and is provided on a first surface of the semiconductor layer 300. As shown in Fig. 6(A), the first semiconductor region 301 is formed in a circular shape in the center of a pixel (section) in a plan view. A cathode contact plug 326 is connected to the center position of the first semiconductor region 301.

[0072] The fourth semiconductor region 304 is a semiconductor region of the second conductivity type (P type in the first embodiment) and is disposed on the light incident side (closer to the second surface) than the first semiconductor region 301. The fourth semiconductor region 304 is formed in a layer shape at a predetermined depth so as to divide the first conductivity type epitaxial layer in one pixel (section) into upper and lower parts. The periphery of the fourth semiconductor region 304 is in contact with the separation part 330 surrounding the pixel. The first conductivity type epitaxial layer located closer to the first surface than the fourth semiconductor region 304 is the fifth semiconductor region 305, and the first conductivity type epitaxial layer located closer to the second surface is the seventh semiconductor region 307.

[0073] The first semiconductor region 301 of the first conductivity type and the fourth semiconductor region 304 of the second conductivity type form an avalanche multiplication unit AM by a PN junction. Signal charges generated in the seventh semiconductor region 307 by photoelectric conversion are collected in the avalanche multiplication unit AM. In order to improve the sensitivity of the pixel (APD 201), it is preferable to increase the size of the seventh semiconductor region 307, which corresponds to the sensitive region.

[0074] The sixth semiconductor region 306 is a semiconductor region of the first conductivity type formed around the first semiconductor region 301. The sixth semiconductor region 306 is also formed in a circular shape in a plan view. Here, the impurity concentrations of the first semiconductor region 301, the sixth semiconductor region 306, and the fifth semiconductor region 305 are in the order of first semiconductor region 301>sixth semiconductor region 306>fifth semiconductor region 305. The sixth semiconductor region 306 is set to satisfy the above relationship. That is, the first semiconductor region 301 has the highest impurity concentration, and the sixth semiconductor region 306 has an impurity concentration between the first semiconductor region 301 and the fifth semiconductor region 305. This makes it possible to ensure electrical connection between the cathode and the first semiconductor region 301 (i.e., the APD 201). The sixth semiconductor region 306 also plays the role of a guard ring for alleviating the electric field.

[0075] The eighth semiconductor region 308 is a buried layer of the second conductivity type provided so as to constitute a part of the second surface of the semiconductor layer 300. The periphery of the eighth semiconductor region 308 is in contact with the separation portion 330 surrounding the pixel. The eighth semiconductor region 308 plays a role in suppressing noise from the second surface side. In addition, a voltage VL from the anode wiring can be supplied to the eighth semiconductor region 308 via the second semiconductor region 302. In this case, a potential gradient can be formed for collecting charges.

[0076] The separation portion 330 is formed by the second semiconductor region 302 of the second conductivity type, and suppresses the movement of electrons between the pixels by a potential barrier. The separation portion 330 also constitutes a part of the second surface of the semiconductor layer 300.

[0077] A third semiconductor region 303 is provided on the first surface of the semiconductor layer 300, which is a connection portion for electrically connecting between the contact plug 324 of the anode wiring and the second semiconductor region 302 of the isolation portion 330. Both the second semiconductor region 302 and the third semiconductor region 303 are of the second conductivity type (P type in the first embodiment).

[0078] 6A, the third semiconductor region 303 is disposed in a portion corresponding to the contact plug 324. In the region other than the third semiconductor region 303, the second conductivity type semiconductor region is not exposed on the first surface.

[0079] 6B, the shape of the microlens 313 is different between the pixels 601 at both ends and the central pixel 602. This difference in shape causes the sensitivity of the pixel 601 to differ from that of the pixel 602. The pixel 601 is a high-sensitivity pixel having a higher sensitivity than the pixel 602, and the pixel 602 is a low-sensitivity pixel having a lower sensitivity than the pixel 601.

[0080] Figures 7(A) and 7(B) show the structure of a sensor substrate 11 of a photoelectric conversion device as a comparative example. Figure 7(A) is a plan view showing the configuration of the pixel region 12, and shows a schematic view of the semiconductor layer 300 of the sensor substrate 11 as viewed from the first surface side. Figure 7(B) is a cross-sectional view taken along line AA in Figure 6(A). As shown in Figures 6(A), 6(B), 7(A), and 7(B), the sensor substrate 11 of the comparative example and the sensor substrate 11 according to the first embodiment have the same basic configuration.

[0081] 7(A) and 7(B), in the comparative example, the size of the high-sensitivity pixel 601 is the same as the size of the low-sensitivity pixel 602. Therefore, the degree of suppression of optical crosstalk (light leakage) from the high-sensitivity pixel 601 to the low-sensitivity pixel 602 and the degree of suppression of optical crosstalk from the low-sensitivity pixel 602 to the high-sensitivity pixel 601 are also the same. In the high-sensitivity pixel 601, avalanche multiplication (avalanche light emission) occurs more strongly than in the low-sensitivity pixel 602. Therefore, the optical crosstalk from the high-sensitivity pixel 601 to the low-sensitivity pixel 602 becomes larger than the optical crosstalk from the low-sensitivity pixel 602 to the high-sensitivity pixel 601.

[0082] Therefore, in the first embodiment, the optical crosstalk (leakage of light) from the high-sensitivity pixel 601 to the low-sensitivity pixel 602 is suppressed more strongly than the optical crosstalk from the low-sensitivity pixel 602 to the high-sensitivity pixel 601. The pixel 602 is made smaller than the high sensitivity pixel 601 (the high sensitivity pixel 601 is made larger than the low sensitivity pixel 602). More specifically, the following condition 1-1 is satisfied. Condition 1-1: In plan view, the distance L1 from the center of the high-sensitivity pixel 601 to the separation portion 330 is longer than the distance L2 from the center of the low-sensitivity pixel 602 to the separation portion 330.

[0083] Furthermore, in the first embodiment, the following condition 1-2 is also satisfied. Condition 1-2: In a plan view, the distance L3 is longer than the distance L4. Here, the distance L3 is the distance from an end of the first semiconductor region 301 on the separation portion 330 side (separation portion side) in the high-sensitivity pixel 601 to the separation portion 330. The distance L4 is the distance from an end of the first semiconductor region 301 on the separation portion 330 side in the low-sensitivity pixel 602 to the separation portion 330.

[0084] By satisfying condition 1-1 (and condition 1-2), the distance from the avalanche multiplication unit AM of the high-sensitivity pixel 601 to the separation unit 330 becomes longer than the distance from the avalanche multiplication unit AM of the low-sensitivity pixel 602 to the separation unit 330. This suppresses optical crosstalk (light leakage) from the high-sensitivity pixel 601 to the low-sensitivity pixel 602 more strongly than optical crosstalk from the low-sensitivity pixel 602 to the high-sensitivity pixel 601. As a result, it is possible to reduce the variation in optical crosstalk (light leakage) between pixels. Specifically, it is possible to reduce the difference between the optical crosstalk from the high-sensitivity pixel 601 to the low-sensitivity pixel 602 and the optical crosstalk from the low-sensitivity pixel 602 to the high-sensitivity pixel 601.

[0085] Although the example of changing the sensitivity of a pixel by changing the shape of the microlens 313 has been described, the method of changing the sensitivity is not limited to this. For example, as shown in Fig. 8, the sensitivity of a pixel may be reduced by using a light-shielding filter 800.

[0086] Second embodiment Figures 9(A) and 9(B) show the structure of a sensor substrate 11 of a photoelectric conversion device according to the second embodiment. Figure 9(A) is a plan view showing the configuration of a pixel region 12, and shows a schematic view of a semiconductor layer 300 of the sensor substrate 11 as viewed from the first surface side. Figure 9(B) is a cross-sectional view taken along line AA in Figure 9(A). Below, configurations different from the first embodiment will be described.

[0087] In the first embodiment, the low sensitivity pixel 602 is smaller than the high sensitivity pixel 601 (the high sensitivity pixel 601 is larger than the low sensitivity pixel 602). In the second embodiment, as shown in FIGS. 9(A) and 9(B), the high sensitivity pixel 601 is provided with a trench 900 that is not provided in the low sensitivity pixel 602. In a plan view, the trench 900 surrounds the first semiconductor region 301 and the sixth semiconductor region 306. The trench 900 is provided at a depth shallower than the fourth semiconductor region 304 when considered in the depth direction from the first surface.

[0088] In the second embodiment, the high-sensitivity pixel 601 and the low-sensitivity pixel 602 are the same size, and conditions 1-1 and 1-2 in the first embodiment are not satisfied. However, by providing a trench 900 in the high-sensitivity pixel 601, optical crosstalk (light leakage) from the high-sensitivity pixel 601 is further suppressed. As a result, the difference between optical crosstalk from the high-sensitivity pixel 601 to the low-sensitivity pixel 602 and optical crosstalk from the low-sensitivity pixel 602 to the high-sensitivity pixel 601 can be reduced.

[0089] In addition, Trench 900 is DTI (Deep Trench Isolation). Alternatively, a metal may be embedded in the DTI to improve light blocking performance. The trench 900 may be made of an insulating film, a fixed charge film, a metal member, polysilicon, or a combination of two or more of these.

[0090] Third embodiment 10(A) to 10(C), 11(A), and 11(B) show the structure of the sensor substrate 11 of the photoelectric conversion device according to the third embodiment. FIGS. 10(A) to 10(C) are plan views showing the configuration of the pixel region 12. FIGS. 10(A) and 10(B) are schematic views showing the semiconductor layer 300 of the sensor substrate 11 viewed from the first surface side, and FIG. 10(C) shows the arrangement of the microlenses 313. FIG. 11(A) is a cross-sectional view taken along line AA in FIG. 10(A), and FIG. 11(B) is a cross-sectional view taken along line BB in FIG. 10(A). Below, configurations different from the first embodiment will be described.

[0091] In the first embodiment, the low-sensitivity pixel 602 is smaller than the high-sensitivity pixel 601 (the high-sensitivity pixel 601 is larger than the low-sensitivity pixel 602). However, in the small low-sensitivity pixel 602, the anode electrode (contact plug 324) supplies an anode potential to the semiconductor region constituting the separation unit 330. Also, the cathode electrode (contact plug 326) supplies a cathode potential to the first semiconductor region 301. The distance between the semiconductor region constituting the separation unit 330 to which the anode potential is supplied and the first semiconductor region 301 to which the cathode potential is supplied becomes shorter, and there is a risk of increasing noise caused by the electric field between these electrodes.

[0092] In the third embodiment, as shown in Figures 11(A) and 11(B), a first isolation section 330-1 and a second isolation section 330-2 are provided as isolation sections that isolate a plurality of pixels. Figure 10(A) shows the arrangement of the first isolation section 330-1, the cathode contact plug 326, and the like, and Figure 10(B) shows the arrangement of the second isolation section 330-2, the anode contact plug 324, the cathode contact plug 326, and the like.

[0093] The first isolation section 330-1 separates the regions of the plurality of pixels on the side closer to the second surface (light incident surface). Specifically, the first isolation section 330-1 separates the regions of the plurality of pixels on the second surface side from the fourth semiconductor region 304. The first isolation section 330-1 corresponds to the isolation section 330 in the first embodiment. The second isolation section 330-2 separates the regions of the plurality of pixels on the side farther from the second surface. Specifically, the second isolation section 330-2 separates the regions of the plurality of pixels on the first surface side from the fourth semiconductor region 304. It is assumed that both the first isolation section 330-1 and the second isolation section 330-2 are formed by semiconductor regions of the second conductivity type.

[0094] 10A, the first separation unit 330-1 is provided so as to satisfy conditions 1-1 and 1-2 in the first embodiment. By doing so, as in the first embodiment, it is possible to reduce the difference between the optical crosstalk from the high-sensitivity pixel 601 to the low-sensitivity pixel 602 and the optical crosstalk from the low-sensitivity pixel 602 to the high-sensitivity pixel 601.

[0095] Moreover, as shown in FIGS. 10(A) and 10(B), the second separation section 330-2 is provided so as to satisfy the following condition 2-1. Condition 2-1: In plan view, the distance L21 from the center of the low-sensitivity pixel 602 to the second separation portion 330-2 is longer than the distance L12 from the center of the low-sensitivity pixel 602 to the first separation portion 330-1.

[0096] By satisfying condition 2-1, the distance between the semiconductor region constituting the second isolation portion 330-2 to which the anode potential is supplied and the first semiconductor region 301 to which the cathode potential is supplied is shortened. This can suppress the generation (increase) of noise.

[0097] Furthermore, in the third embodiment, as shown in FIGS. 10(A) and 10(B), the following condition 2-2 is also satisfied. Condition 2-2: In plan view, the distance L22 from the center of the high-sensitivity pixel 601 to the second separation portion 330-2 is approximately equal to the distance L21 from the center of the low-sensitivity pixel 602 to the second separation portion 330-2.

[0098] By satisfying condition 2-2, it is possible to reduce the variation in the effect of the electric field between the anode and cathode on the pixels. Specifically, it is possible to reduce the difference between the effect of the electric field between the anode and cathode on the high-sensitivity pixel 601 and the effect of the electric field between the anode and cathode on the low-sensitivity pixel 602.

[0099] Note that condition 2-2 may also be interpreted as condition 2-3 below. Condition 2-3: In plan view, the distance from the cathode electrode (contact plug 326) to the anode electrode (contact plug 324) of the high-sensitivity pixel 601 is approximately equal to the distance from the cathode electrode to the anode electrode of the low-sensitivity pixel 602.

[0100] (Fourth embodiment) 12(A) to 12(C), 13(A), and 13(B) show the structure of the sensor substrate 11 of the photoelectric conversion device according to the fourth embodiment. FIGS. 12(A) to 12(C) are plan views showing the configuration of the pixel region 12. FIGS. 12(A) and 12(B) are schematic views showing the semiconductor layer 300 of the sensor substrate 11 viewed from the first surface side, and FIG. 12(C) is schematic showing the arrangement of the microlenses 313. FIG. 12(A) shows the arrangement of the first separation section 330-1, the cathode contact plug 326, and the like, and FIG. 12(B) shows the arrangement of the second separation section 330-2, the anode contact plug 324, the cathode contact plug 326, and the like. FIG. 13(A) is a cross-sectional view taken along the line AA in FIG. 12(A), and FIG. 13(B) is a cross-sectional view taken along the line BB in FIG. 12(A). Hereinafter, the configuration different from the third embodiment will be described.

[0101] In the third embodiment, one low sensitivity pixel 602 is arranged for three high sensitivity pixels 601. Specifically, as shown in Figures 10(A) to 10(C), four pixels, that is, three high sensitivity pixels 601 and one low sensitivity pixel 602, are arranged in two rows and two columns.

[0102] In the fourth embodiment, one low sensitivity pixel 602 is arranged for every four high sensitivity pixels 601. Specifically, as shown in Figures 12(A) to 12(C), one low sensitivity pixel 602 is arranged in the center of four high sensitivity pixels 601 arranged in two rows and two columns. In this way, a Bayer array of the high sensitivity pixels 601 can be realized.

[0103] Furthermore, in the fourth embodiment, the conditions 1-1 and 1-2 in the first embodiment and the conditions 2-1 and 2-2 in the third embodiment are both satisfied, so that the same effects as in the first embodiment and the third embodiment can be obtained.

[0104] Fifth embodiment 14(A) to 14(C) and 15(A) to 15(C) show the structure of a sensor substrate 11 of a photoelectric conversion device according to a fifth embodiment. FIGS. 14(A) to 14(C) are plan views showing the configuration of a pixel region 12. FIG. 14(A) shows a schematic diagram of a semiconductor layer 300 of the sensor substrate 11 as viewed from the first surface side, and FIG. 14(B) shows a bonding portion 328 (metal bond). 14(A) and 14(B) typically show the arrangement of microlenses 313. Fig. 15(A) is a cross-sectional view taken along line AA in Fig. 14(A), Fig. 15(B) is a cross-sectional view taken along line BB in Fig. 14(A), and Fig. 15(C) is a cross-sectional view taken along line CC in Fig. 14(A). Configurations different from the first embodiment will now be described.

[0105] In the first embodiment, the low-sensitivity pixel 602 is smaller than the high-sensitivity pixel 601 (the high-sensitivity pixel 601 is larger than the low-sensitivity pixel 602). In such a configuration, the arrangement of the cathode electrode (contact plug 326) and the arrangement of the metal bonding (joint 328) affect the improvement of the pixel integration density and the miniaturization of the pixels.

[0106] Therefore, in the fifth embodiment, the arrangement of the cathode electrodes (contact plugs 326) and the arrangement of the metal bonding (joints 328) are optimized to improve the integration density of pixels and to make the pixels finer. In the fifth embodiment, as shown in FIGS. 14(A) to 14(C), a plurality of high-sensitivity pixels 601 are arranged at approximately equal intervals in each of the row direction (first direction) and the column direction (second direction perpendicular to the first direction). Similarly, a plurality of low-sensitivity pixels 602 are arranged at approximately equal intervals in each of the row direction and the column direction. Then, a plurality of cathode electrodes (contact plugs 326) corresponding to a plurality of pixels including a plurality of high-sensitivity pixels 601 and a plurality of low-sensitivity pixels 602 are arranged at approximately equal intervals in each of the first diagonal direction and the second diagonal direction. The first diagonal direction is a direction that bisects the row direction and the column direction (a third direction that bisects the first direction and the second direction), and the second diagonal direction is a direction perpendicular to the first diagonal direction (a fourth direction perpendicular to the third direction). Furthermore, as shown in FIG. 14B, the positions of the multiple bonding parts 328 (metal bonding) corresponding to the multiple pixels are set to be substantially equal to the positions of the multiple cathode electrodes (contact plugs 326).

[0107] This makes it easy to adopt a configuration in which the low-sensitivity pixels 602 are shifted by 1 / 2 pitch with respect to the high-sensitivity pixels 601 (a configuration in which one low-sensitivity pixel 602 is disposed approximately at the center of four high-sensitivity pixels 601 arranged in two rows and two columns). This in turn makes it possible to improve the integration density of pixels and to miniaturize pixels.

[0108] Furthermore, in the fifth embodiment, as shown in FIG. 14(A), the interval between the cathode electrode (contact plug 326) and the anode electrode (contact plug 324) is substantially constant. Moreover, the cathode electrode (contact plug 326) and the anode electrode (contact plug 324) are arranged at substantially equal intervals in each of the row direction and the column direction. The cathode electrode (contact plug 326) and the anode electrode (contact plug 324) are also arranged at substantially equal intervals in each of the first diagonal direction and the second diagonal direction. This arrangement also makes it possible to improve the integration density of pixels and to miniaturize the pixels.

[0109] 14A, the anode electrodes (contact plugs 324) are disposed on all four sides of the high-sensitivity pixel 601, but the anode electrodes may be thinned out. Alternatively, one anode electrode may be provided for multiple pixels.

[0110] 15(C), in the fifth embodiment, there is a portion on the first surface side of the sensitive region (seventh semiconductor region 307) where the separation portion 330 is not present. By not exposing the separation portion 330 (second semiconductor region 302) to the first surface, it is possible to prevent electric charges (noise) generated near the first surface from entering the sensitive region through the semiconductor region of the second conductivity type.

[0111] Sixth embodiment 16(A) to 16(C) and 17(A) to 17(C) show photoelectric conversion devices according to the sixth embodiment. 16(A)-16(C) are plan views showing the configuration of the pixel region 12. FIG. 16(A) is a schematic diagram showing the semiconductor layer 300 of the sensor substrate 11 viewed from the first surface side, FIG. 16(B) is a schematic diagram showing the arrangement of the bonding portion 328 (metal bonding), and FIG. 16(C) is a schematic diagram showing the arrangement of the microlens 313. FIG. 17(A) is a cross-sectional view taken along line AA in FIG. 16(A), FIG. 17(B) is a cross-sectional view taken along line BB in FIG. 16(A), and FIG. 17(C) is a cross-sectional view taken along line CC in FIG. 16(A). Below, a configuration different from the fifth embodiment will be described.

[0112] In the sixth embodiment, as in the fifth embodiment, one low-sensitivity pixel 602 is arranged substantially at the center of four high-sensitivity pixels 601 arranged in two rows and two columns, as shown in FIGS. 16(A) to 16(C).

[0113] Furthermore, in the sixth embodiment, as shown in Figures 16(A) to 16(C), the separation section 330 surrounds the high-sensitivity pixel 601 with an approximately octagon, and surrounds the low-sensitivity pixel 602 with an approximately quadrangle formed by four approximately octagons corresponding to the four high-sensitivity pixels 601, respectively.

[0114] 17(A) to 17(C), in the sixth embodiment, a trench 1700 that does not penetrate in the depth direction is formed in the separation section 330. By forming the trench 1700, optical crosstalk can be further reduced.

[0115] By making the separation unit 330 surround the high-sensitivity pixel 601 in a substantially octagonal shape, it is possible to reduce the number of right-angled portions of the separation unit 330. By reducing the number of right-angled portions, it is possible to suppress electric field concentration. In addition, it becomes easier to form a trench, and it is possible to reduce damage to the semiconductor region when forming the trench, and it is possible to suppress the occurrence (increase) of noise due to the damage.

[0116] In the fifth embodiment, as shown in Fig. 14C, a part of the microlens 313 of the high-sensitivity pixel 601 overlaps the region of the low-sensitivity pixel 602, causing unnecessary light to be incident on the low-sensitivity pixel 602. On the other hand, in the sixth embodiment, the separation unit 330 surrounds the high-sensitivity pixel 601 in a substantially octagonal shape, so that it is possible to prevent the microlens 313 of another pixel from overlapping the region of the pixel, as shown in Fig. 16C. As a result, it is possible to prevent unnecessary light from being incident on the pixel.

[0117] Seventh embodiment Figures 18, 19(A) to 19(C) show the structure of the sensor substrate 11 of the photoelectric conversion device according to the seventh embodiment. Figure 18 is a plan view showing the configuration of the pixel region 12, and shows a schematic view of the semiconductor layer 300 of the sensor substrate 11 as viewed from the first surface side. Figure 19(A) is a cross-sectional view taken along line AA in Figure 18, Figure 19(B) is a cross-sectional view taken along line BB in Figure 18, and Figure 19(C) is a cross-sectional view taken along line CC in Figure 18. Below, configurations different from the sixth embodiment will be described.

[0118] In the sixth embodiment, as shown in Figures 17(A) to 17(C), a trench 1700 that does not penetrate in the depth direction is formed in the separation part 330. In the seventh embodiment, as shown in Figures 19(A) to 19(C), a trench 1900 that penetrates in the depth direction is formed in the separation part 330. By making the trench penetrate, it is possible to reduce emission crosstalk more than when the trench is not penetrated.

[0119] When the trench is penetrated, it is necessary to dispose an anode electrode (contact plug 324) for each of the two pixels that sandwich the trench. 16(A) and 17(A) to 17(C)) and the seventh embodiment (FIGS. 18, 19(A) to 19(C)) are different in the number and arrangement of contact plugs 324 (and third semiconductor regions 303).

[0120] The arrangement of the anode electrodes (contact plugs 324) is not particularly limited, and for example, as shown in Fig. 20, multiple anode electrodes (contact plugs 324) may be gathered in one place. This makes it possible to further improve the integration density of pixels and further miniaturize the pixels. The configuration of Fig. 20, in which the separation unit 330 surrounds the high-sensitivity pixels 601 in a substantially octagonal shape and surrounds the low-sensitivity pixels 602 in a substantially rectangular shape, is a configuration that makes it easy to gather multiple anode electrodes (contact plugs 324) in one place.

[0121] Eighth embodiment 21(A), 21(B), and 22(A) to 22(C) show the structure of the sensor substrate 11 of the photoelectric conversion device according to the eighth embodiment. FIGS. 21(A) and 21(B) are plan views showing the configuration of the pixel region 12, and are schematic views showing the semiconductor layer 300 of the sensor substrate 11 viewed from the first surface side. FIG. 22(A) is a cross-sectional view taken along line AA in FIG. 21(A), FIG. 22(B) is a cross-sectional view taken along line BB in FIG. 21(A), and FIG. 22(C) is a cross-sectional view taken along line CC in FIG. 21(A). Below, configurations different from the sixth embodiment will be described.

[0122] In the eighth embodiment, as in the third and fourth embodiments, a first isolation portion 330-1 and a second isolation portion 330-2 are provided as isolation portions for isolating a plurality of pixels, as shown in Figures 21(A), 21(B), and 22(A) to 22(C). Figure 21(A) shows the arrangement of the first isolation portion 330-1, the cathode contact plug 326, and the like, and Figure 21(B) shows the arrangement of the second isolation portion 330-2, the anode contact plug 324, the cathode contact plug 326, and the like.

[0123] Furthermore, in the eighth embodiment, the conditions 1-1 and 1-2 in the first embodiment and the conditions 2-1 and 2-2 in the third embodiment are satisfied. The other configurations are the same as those in the sixth embodiment. As shown in FIG. 21(B), the second separation parts 330-2 are arranged at substantially equal intervals in each of the first and second oblique directions. This makes it easier to satisfy the conditions 2-1 and 2-2.

[0124] As described above, in the eighth embodiment, it is possible to obtain the same effects as in the first embodiment, the third embodiment, the fourth embodiment, and the sixth embodiment.

[0125] Ninth embodiment 23, 24(A) to 24(C) show the structure of the sensor substrate 11 of the photoelectric conversion device according to the ninth embodiment. FIG. 23 is a plan view showing the configuration of the pixel region 12, and shows a schematic view of the semiconductor layer 300 of the sensor substrate 11 viewed from the first surface side. FIG. 23 shows the arrangement of the second isolation portion 330-2, the anode contact plug 324, the cathode contact plug 326, and the like. FIG. 24(A) is a cross-sectional view taken along line AA in FIG. 23, FIG. 24(B) is a cross-sectional view taken along line BB in FIG. 23, and FIG. 24(C) is a cross-sectional view taken along line CC in FIG. 23. Hereinafter, the configuration different from the eighth embodiment will be described.

[0126] In the ninth embodiment, as shown in FIGS. 24(A) to 24(C), a non-penetrating trench 1901 is formed in the first isolation portion 330-1 in the depth direction. Also, a non-penetrating trench 1902 is formed as the second isolation portion 330-2. In the eighth embodiment, the second isolation portion 330-2 is formed from the fourth semiconductor region 304 to the first surface side, but the trench 1902 in the ninth embodiment is formed up to the second surface side of the fourth semiconductor region 304. Trench 1901 , 1902, optical crosstalk can be further reduced. The trenches 1901, 1902 may be DTI (Deep Trench Isolation). The trenches 1901, 1902 may be made of an insulating film, a fixed charge film, a metal member, polysilicon, or a combination of a plurality of these. For example, the trench 1901 may be filled with an insulating film, and the trench 1902 may be filled with a metal. The trenches 1901 and 1902 may be filled with the same material.

[0127] As shown in FIG. 23, the ninth embodiment is characterized in that the arrangement of the cathode electrodes (contact plugs 326) and the anode electrodes (contact plugs 324) is the same in the high-sensitivity pixel 601 and the low-sensitivity pixel 602.

[0128] Tenth embodiment The photoelectric conversion system according to this embodiment will be described with reference to Fig. 25. Fig. 25 is a block diagram showing a schematic configuration of the photoelectric conversion system according to this embodiment.

[0129] The photoelectric conversion devices described in the first to ninth embodiments are applicable to various photoelectric conversion systems. The photoelectric conversion system includes at least the photoelectric conversion device according to the above embodiments and a signal processing unit that processes a signal output from the photoelectric conversion device. Examples of devices to which such photoelectric conversion systems can be applied include digital still cameras, digital camcorders, security cameras, copiers, fax machines, mobile phones, vehicle-mounted cameras, observation satellites, sensors, and measuring instruments. Camera modules that include an optical system such as a lens and an imaging device are also included in devices to which the photoelectric conversion system is applied. FIG. 25 illustrates a block diagram of a digital still camera as an example of these devices.

[0130] 25 includes an image pickup device 2504, which is an example of a photoelectric conversion device, and a lens 2502 that forms an optical image of a subject on the image pickup device 2504. The photoelectric conversion system also includes an aperture 2503 for varying the amount of light passing through the lens 2502, and a barrier 2501 for protecting the lens 2502. The lens 2502 and the aperture 2503 are an optical system that focuses light on the image pickup device 2504. The image pickup device 2504 is a photoelectric conversion device (image pickup device) according to any one of the above embodiments, and converts the optical image formed by the lens 2502 into an electrical signal.

[0131] The photoelectric conversion system also has a signal processing unit 2507 which is an image generating unit that generates an image by processing an output signal output from the imaging device 2504. The signal processing unit 2507 performs various corrections and compression as necessary to output image data. The signal processing unit 2507 may be formed on a semiconductor substrate on which the imaging device 2504 is provided, or may be formed on a semiconductor substrate separate from the imaging device 2504. Moreover, the imaging device 2504 and the signal processing unit 2507 may be formed on the same semiconductor substrate.

[0132] The photoelectric conversion system further includes a memory unit 2510 for temporarily storing image data, and an external interface unit (external I / F unit) 2513 for communicating with an external computer or the like. The photoelectric conversion system further includes a recording medium 2512 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) 2511 for recording or reading out data on the recording medium 2512. The recording medium 2512 may be built into the photoelectric conversion system, or may be removable.

[0133] The photoelectric conversion system further includes an overall control / calculation unit 2509 that performs various calculations and controls the entire digital still camera, and a timing generation unit 2508 that outputs various timing signals to the image pickup device 2504 and the signal processing unit 2507. Here, the timing signals may be input from outside, and the photoelectric conversion system includes at least the image pickup device 2504 and the signal output from the image pickup device 2504. and a signal processor 2507 for processing the input output signal.

[0134] The imaging device 2504 outputs an imaging signal to the signal processing unit 2507. The signal processing unit 2507 performs predetermined signal processing on the imaging signal output from the imaging device 2504, and outputs image data. The signal processing unit 2507 generates an image using the imaging signal.

[0135] 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.

[0136] Eleventh embodiment The photoelectric conversion system and the moving object of this embodiment will be described with reference to Fig. 26(A) and Fig. 26(B). Fig. 26(A) is a diagram showing the configuration of the photoelectric conversion system of this embodiment, and Fig. 26(B) is a diagram showing the configuration of the moving object of this embodiment.

[0137] FIG. 26(A) shows an example of a photoelectric conversion system related to an in-vehicle camera. The photoelectric conversion system 2600 has an image capture device 2610. The image capture device 2610 is the photoelectric conversion device (image capture device) described in any of the above embodiments. The photoelectric conversion system 2600 has an image processing unit 2612 that performs image processing on a plurality of image data acquired by the image capture device 2610. The photoelectric conversion system 2600 also has a distance acquisition unit 2616 that calculates a distance to an object, and a collision determination unit 2618 that determines whether or not there is a possibility of collision based on the calculated distance. Here, the distance acquisition unit 2616 may acquire distance information to the object using ToF (Time Of Flight), or may acquire distance information using parallax information or the like. That is, the distance information is information related to parallax, defocus amount, distance to the object, and the like. The collision determination unit 2618 may determine the possibility of collision using any of these distance information. The distance information acquisition means may be realized by dedicated hardware or may be realized by a software module. It may also 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.

[0138] The photoelectric conversion system 2600 is connected to a vehicle information acquisition device 2620, and can acquire vehicle information such as vehicle speed, yaw rate, and steering angle. The photoelectric conversion system 2600 is also connected to an ECU 2630, which is a control device that outputs a control signal to generate a braking force for the vehicle based on the judgment result of the collision judgment unit 2618. The photoelectric conversion system 2600 is also connected to an alarm device 2640 that issues an alarm to the driver based on the judgment result of the collision judgment unit 2618. For example, when the judgment result of the collision judgment unit 2618 indicates that a collision is highly likely, the ECU 2630 performs vehicle control to avoid a collision and reduce damage by applying the brakes, releasing the accelerator, suppressing engine output, etc. The alarm device 2640 warns the user by sounding an alarm, displaying alarm information on the screen of a car navigation system, etc., and vibrating the seat belt or steering wheel.

[0139] In this embodiment, the surroundings of the vehicle, for example, the front or rear, are imaged by the photoelectric conversion system 2600. Fig. 26(B) shows a photoelectric conversion system for imaging the area in front of the vehicle (imaging range 2650). A vehicle information acquisition device 2620 sends an instruction to the photoelectric conversion system 2600 or the imaging device 2610. This configuration can further improve the accuracy of distance measurement.

[0140] 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 to follow other vehicles, control of automatic driving not to stray from lanes, etc. Furthermore, the photoelectric conversion system is not limited to vehicles such as automobiles, but can be applied to, for example, ships, aircraft, etc. or an industrial robot or other moving body (moving device). The moving body includes one or both of a driving force generating unit that generates a driving force mainly used to move the moving body, and a rotating body mainly used to move the moving body. The driving force generating unit may be an engine, a motor, or the like. The rotating body may be a tire, a wheel, a screw of a ship, a propeller of an aircraft, or the like. In addition, the present invention may be applied not only to moving bodies, but also to a wide range of devices that use object recognition, such as an intelligent transport system (ITS).

[0141] Twelfth embodiment The photoelectric conversion system of this embodiment will be described with reference to Fig. 27. Fig. 27 is a block diagram showing an example of the configuration of a range image sensor which is the photoelectric conversion system of this embodiment.

[0142] 27, the distance image sensor 2701 is configured to include an optical system 2707, a photoelectric conversion device 2708, an image processing circuit 2704, a monitor 2705, and a memory 2706. The distance image sensor 2701 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 2709 toward the subject and reflected from the surface of the subject.

[0143] The optical system 2707 is configured to have one or more lenses, and guides image light (incident light) from a subject to a photoelectric conversion device 2708 , forming an image on the light receiving surface (sensor portion) of the photoelectric conversion device 2708 .

[0144] As the photoelectric conversion device 2708 , the photoelectric conversion device of each of the above-mentioned embodiments is applied, and a distance signal indicating a distance determined from a light receiving signal output from the photoelectric conversion device 2708 is supplied to the image processing circuit 2704 .

[0145] The image processing circuit 2704 performs image processing to construct a distance image based on the distance signal supplied from the photoelectric conversion device 2708. The distance image (image data) obtained by this image processing is then supplied to a monitor 2705 for display, or supplied to a memory 2706 for storage (recording).

[0146] In the range image sensor 2701 configured in this way, by applying the above-mentioned photoelectric conversion device, it is possible to obtain, for example, a more accurate range image as the pixel characteristics improve.

[0147] Thirteenth embodiment The photoelectric conversion system of this embodiment will be described with reference to Fig. 28. Fig. 28 is a diagram showing an example of a schematic configuration of an endoscopic surgery system which is the photoelectric conversion system of this embodiment.

[0148] 28 shows a state in which an operator (doctor) 2831 is performing surgery on a patient 2832 on a patient bed 2833 using an endoscopic surgery system 2850. As shown in the figure, the endoscopic surgery system 2850 is composed of an endoscope 2800, a surgical tool 2810, and a cart 2834 on which various devices for endoscopic surgery are mounted.

[0149] The endoscope 2800 is composed of a lens barrel 2801, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 2832, and a camera head 2802 connected to the base end of the lens barrel 2801. In the illustrated example, the endoscope 2800 is configured as a so-called rigid lens barrel having a rigid lens barrel 2801, but the endoscope 2800 may be configured as a so-called flexible lens barrel having a flexible lens barrel.

[0150] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 2801. A light source device 2803 is connected to the endoscope 2800, and light generated by the light source device 2803 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 2801, and is irradiated via the objective lens toward an observation target in a body cavity of a patient 2832. The endoscope 2800 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0151] An optical system and a photoelectric conversion device are provided inside the camera head 2802, and reflected light (observation light) from an observation target is collected by the optical system onto the photoelectric conversion device. 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 may be any of the photoelectric conversion devices (imaging devices) described in the above-described embodiments. The image signal is transmitted to a camera control unit (CCU) 2835 as RAW data.

[0152] The CCU 2835 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and performs overall control of the operations of the endoscope 2800 and the display device 2836. Furthermore, the CCU 2835 receives an image signal from the camera head 2802, 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.

[0153] Under the control of the CCU 2835 , the display device 2836 displays an image based on an image signal that has been subjected to image processing by the CCU 2835 .

[0154] The light source device 2803 is composed of a light source such as an LED (Light Emitting Diode), and supplies the endoscope 2800 with irradiation light when photographing an operation site or the like.

[0155] The input device 2837 is an input interface for the endoscopic surgery system 2850. A user can input various information and instructions to the endoscopic surgery system 2850 via the input device 2837.

[0156] The treatment tool control device 2838 controls the driving of the energy treatment tool 2812 for cauterizing tissue, incising, sealing blood vessels, or the like.

[0157] The light source device 2803 that supplies irradiation light to the endoscope 2800 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 2803. 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 2802 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.

[0158] Furthermore, the light source device 2803 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 2802 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.

[0159] The light source device 2803 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 2803 may be configured to supply narrow band light and / or excitation light corresponding to such special light observation.

[0160] Fourteenth embodiment The photoelectric conversion system of this embodiment will be described with reference to Figs. 29(A) and 29(B). Fig. 29(A) describes glasses 2900 (smart glasses) which are the photoelectric conversion system of this embodiment. The glasses 2900 have a photoelectric conversion device 2902. The photoelectric conversion device 2902 is the photoelectric conversion device (imaging 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 2901. The photoelectric conversion device 2902 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 2902 is not limited to that shown in Fig. 29(A).

[0161] The glasses 2900 further include a control device 2903. The control device 2903 functions as a power source that supplies power to the photoelectric conversion device 2902 and the display device. The control device 2903 also controls the operations of the photoelectric conversion device 2902 and the display device. The lens 2901 is formed with an optical system for collecting light on the photoelectric conversion device 2902.

[0162] FIG. 29(B) illustrates glasses 2910 (smart glasses) according to one application example. The glasses 2910 have a control device 2912, and the control device 2912 is equipped with a photoelectric conversion device corresponding to the photoelectric conversion device 2902 and a display device. The lens 2911 is formed with an optical system for projecting light emitted from the photoelectric conversion device in the control device 2912 and the display device, and an image is projected onto the lens 2911. The control device 2912 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 to detect the line of sight. The infrared light emitting unit emits infrared light toward 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 emitting unit to the display unit in a planar view, deterioration of image quality is reduced.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] 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 display area and the second display 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.

[0168] In addition, AI may be used to determine the first field of view area and the area 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 the image of the eyeball and the direction in which the eyeball in the image was actually looking as teacher data. 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.

[0169] 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.

[0170] Fifteenth embodiment The above-described photoelectric conversion device and photoelectric conversion system may be applied to electronic devices such as so-called smartphones and tablets.

[0171] 30(A) and 30(B) are diagrams showing an example of an electronic device 3000 equipped with a photoelectric conversion device. Fig. 30(A) shows the front side of the electronic device 3000, and Fig. 30(B) shows the rear side of the electronic device 3000.

[0172] 30(A), a display 3010 for displaying an image is disposed in the center of the surface of the electronic device 3000. Along the upper side of the surface of the electronic device 3000, front cameras 3021 and 3022 using photoelectric conversion devices, an IR light source 3030 for emitting infrared light, and a visible light source 3040 for emitting visible light are disposed.

[0173] Also, as shown in FIG. 30(B), rear cameras 3051 and 3052 using photoelectric conversion devices, an IR light source 3060 that emits infrared light, and a visible light source 3070 that emits visible light are arranged along the upper edge of the back surface of the electronic device 3000.

[0174] In the electronic device 3000 configured in this manner, by applying the above-mentioned photoelectric conversion device, for example, it is possible to capture a higher quality image. Note that the photoelectric conversion device can also be applied to other electronic devices such as infrared sensors, distance measuring sensors using active infrared light sources, security cameras, and personal or biometric authentication cameras. This can improve the accuracy, performance, and the like of these electronic devices.

[0175] Sixteenth embodiment 31 is a block diagram of an X-ray CT apparatus in this embodiment. The above-mentioned photoelectric conversion device and photoelectric conversion system are applicable to the detector of the X-ray CT apparatus. The X-ray CT apparatus 3100 includes an X-ray generating unit 3110, a wedge 3111, a collimator 3112, an X-ray detecting unit 3120, a top plate 3130, a rotating frame 3140, and a high voltage generating unit 3150. The X-ray CT apparatus 3100 further includes a data acquisition system (DAS) 3151, a signal processing unit 3152, a display unit 3153, and a control unit 3154.

[0176] The X-ray generating unit 3110 is composed of, for example, a vacuum tube that generates X-rays. A high voltage and a filament current are supplied to the vacuum tube of the X-ray generating unit 3110 from a high voltage generator 3150. X-rays are generated by irradiating thermal electrons from the cathode (filament) toward the anode (target).

[0177] The wedge 3111 is a filter that adjusts the amount of X-rays irradiated from the X-ray generating unit 3110. The wedge 3111 attenuates the amount of X-rays so that the X-rays irradiated from the X-ray generating unit 3110 to the subject have a predetermined distribution. The collimator 3112 is made of a lead plate or the like that narrows down the irradiation range of the X-rays that have passed through the wedge 3111. The X-rays generated by the X-ray generating unit 3110 are shaped into a cone beam via the collimator 3112 and irradiated to the subject on the tabletop 3130.

[0178] The X-ray detection unit 3120 is configured using the above-mentioned photoelectric conversion device or photoelectric conversion system. The X-ray detection unit 3120 detects X-rays that have passed through the subject from the X-ray generation unit 3110, and outputs a signal corresponding to the X-ray dose to the DAS 3151.

[0179] The rotating frame 3140 has an annular shape and is configured to be rotatable. An X-ray generation unit 3110 (wedge 3111, collimator 3112) and an X-ray detection unit 3120 are arranged facing each other inside the rotating frame 3140. The X-ray generation unit 3110 and the X-ray detection unit 3120 are rotatable together with the rotating frame 3140.

[0180] The high voltage generator 3150 includes a boost circuit, and outputs a high voltage to the X-ray generation unit 3110. The DAS 3151 includes an amplifier circuit and an A / D conversion circuit, and outputs a signal from the X-ray detection unit 3120 to the signal processing unit 3152 as digital data.

[0181] The signal processing unit 3152 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory), and is capable of executing image processing on digital data. The display unit 3153 includes a flat display device, and is capable of displaying X-ray images. The control unit 3154 includes a CPU, a ROM, a RAM, and the like, and controls the operation of the entire X-ray CT device 3100.

[0182] Seventeenth embodiment A photoelectric conversion system according to the 17th embodiment will be described with reference to Fig. 32. Fig. 32 is a block diagram showing a schematic configuration of an imaging system SYS, which is a photoelectric conversion system according to the 17th embodiment. The imaging system SYS includes at least a photoelectric conversion device according to the above embodiment and a signal processing unit that processes a signal output from the photoelectric conversion device.

[0183] The imaging system SYS is an information terminal having a camera and a photographing function. The imaging system SYS is constructed using an imaging device IS. The imaging device IS may further include a package PKG that houses an imaging device IC. The package PKG may include a base to which the imaging device IC is fixed, and a lid that faces the imaging device IC. The package PKG may include a connection member (a member that connects a terminal provided on the base with a terminal provided on the imaging device IC). The imaging device IS may also mount a plurality of imaging device ICs side by side in a common package PKG. Also, the imaging device IS may mount a plurality of imaging device ICs side by side in a common package PKG. The IC can also be stacked with other semiconductor device ICs.

[0184] The imaging system SYS may include an optical system OU (optical device) that forms an image on the imaging device IS. The imaging system SYS may also include at least one of a control device CU, a processing device PU, a display device DU, and a storage device MU. The control device CU controls the imaging device IS, and the processing device PU processes signals obtained from the imaging device IS. The display device DU displays images obtained from the imaging device IS, and the storage device MU stores images obtained from the imaging device IS.

[0185] (others) Although various devices have been described in the above embodiment, a mechanical device may be further provided. The mechanical device in the camera can drive optical components for zooming, focusing, and shutter operation. Alternatively, the mechanical device in the camera can move a photoelectric conversion device for vibration reduction operation.

[0186] The device may be transportation equipment such as a vehicle, ship, or aircraft. A mechanical device in transportation equipment may be used as a moving device. The device as transportation equipment is suitable for transporting a photoelectric conversion device or for assisting and / or automating driving (piloting) by using an imaging function. A processing device for assisting and / or automating driving (piloting) can perform processing for operating the mechanical device as a moving device based on information obtained by the photoelectric conversion device.

[0187] The above-described embodiments can be modified as appropriate without departing from the technical concept. The disclosure of this specification includes not only what is described in this specification, but also all matters that can be understood from this specification and the drawings attached hereto. The disclosure of this specification also includes the complement of the concepts described in this specification. In other words, if this specification contains a statement that "A is greater than B," for example, this specification can be said to disclose that "A is not greater than B" even if the statement that "A is not greater than B" is omitted. This is because when it is stated that "A is greater than B," it is assumed that the case in which "A is not greater than B" is taken into consideration.

[0188] In the present specification, expressions such as "A or B", "at least one of A and B", "at least one of A or / and B", "one or more of A or / and B" may be used. In this case, unless otherwise expressly defined, all possible combinations of the listed items can be included. That is, the above expressions are understood to disclose all cases including at least one A, at least one B, and both at least one A and at least one B. This applies equally to combinations of three or more elements.

[0189] The disclosure of this embodiment includes the following configuration. (Configuration 1) a first pixel including a first avalanche photodiode; a second pixel including a second avalanche photodiode; a separation portion separating the first pixel and the second pixel; having In a plan view, the distance from the center of the first pixel to the separation portion is longer than the distance from the center of the second pixel to the separation portion. A photoelectric conversion device comprising: (Configuration 2) The separation portion is a region close to the light incident surface of the first pixel and a region close to the light incident surface of the second pixel. a first separation section that separates the region closer to the surface from the region closer to the surface; the photoelectric conversion device further includes a second separation section separating an area of ​​the first pixel farther from the light incident surface from an area of ​​the second pixel farther from the light incident surface, In the plan view, a distance from a center of the second pixel to the second isolation portion is longer than a distance from a center of the second pixel to the first isolation portion. 2. The photoelectric conversion device according to configuration 1. (Configuration 3) the separation portion is a first separation portion that separates a region of the first pixel that is closer to the light incident surface from a region of the second pixel that is closer to the light incident surface, the photoelectric conversion device further includes a second separation section separating an area of ​​the first pixel farther from the light incident surface from an area of ​​the second pixel farther from the light incident surface, In the plan view, the distance from the center of the first pixel to the second separation portion is substantially equal to the distance from the center of the second pixel to the second separation portion. 2. The photoelectric conversion device according to configuration 1. (Configuration 4) the first avalanche photodiode includes a first semiconductor region of a first conductivity type; the second avalanche photodiode includes a second semiconductor region of the first conductivity type; The photoelectric conversion device of any one of configurations 1 to 3, characterized in that, in the planar view, the distance from the end of the first semiconductor region on the isolation portion side to the isolation portion is longer than the distance from the end of the second semiconductor region on the isolation portion side to the isolation portion. (Configuration 5) A plurality of first pixels are arranged at substantially equal intervals in a first direction and in a second direction perpendicular to the first direction, a plurality of second pixels are arranged at substantially equal intervals in each of the first direction and the second direction; A plurality of second separation portions are disposed at substantially equal intervals in each of a third direction that equally bisects the first direction and the second direction and a fourth direction perpendicular to the third direction. 4. The photoelectric conversion device according to claim 2 or 3. (Configuration 6) In the plan view, a distance from a cathode electrode to an anode electrode of the first pixel is substantially equal to a distance from a cathode electrode to an anode electrode of the second pixel. 4. The photoelectric conversion device according to configuration 3. (Configuration 7) A plurality of cathode electrodes respectively corresponding to a plurality of pixels including the plurality of first pixels and the plurality of second pixels are disposed at substantially equal intervals in each of the third direction and the fourth direction. 6. The photoelectric conversion device according to configuration 5. (Configuration 8) The separation unit separates the plurality of pixels, In the plan view, The second pixel is disposed substantially at the center of four first pixels arranged in two rows and two columns, The separation portion surrounds the first pixel with a substantial octagon, and surrounds the second pixel with a substantial rectangle formed by four substantial octagons corresponding to the four first pixels, respectively. 8. The photoelectric conversion device according to configuration 7. (Configuration 9) Further, the light receiving surface has a plurality of metal bondings on a side opposite to the light receiving surface, the metal bondings corresponding to the plurality of pixels, respectively. In the plan view, the positions of the metal bonds are substantially equal to the positions of the cathode electrodes. 9. The photoelectric conversion device according to configuration 7 or 8. (Configuration 10) a first pixel including a first avalanche photodiode and a second pixel including a second avalanche photodiode; The light leakage from the first pixel to the second pixel is suppressed more strongly than the light leakage from the second pixel to the first pixel. A photoelectric conversion device comprising: (Configuration 11) a separation portion separating the first pixel and the second pixel, In a plan view, the distance from the center of the first pixel to the separation portion is longer than the distance from the center of the second pixel to the separation portion. 11. The photoelectric conversion device according to configuration 10. (Configuration 12) the first avalanche photodiode includes a first semiconductor region of a first conductivity type; the second avalanche photodiode includes a second semiconductor region of the first conductivity type; The photoelectric conversion device described in configuration 11, characterized in that, in the planar view, the distance from the end of the first semiconductor region on the isolation portion side to the isolation portion is longer than the distance from the end of the second semiconductor region on the isolation portion side to the isolation portion. (Configuration 13) the separation portion is a first separation portion that separates a region of the first pixel that is closer to the light incident surface from a region of the second pixel that is closer to the light incident surface, the photoelectric conversion device further includes a second separation section separating an area of ​​the first pixel farther from the light incident surface from an area of ​​the second pixel farther from the light incident surface, In the plan view, a distance from a center of the second pixel to the second isolation portion is longer than a distance from a center of the second pixel to the first isolation portion. 13. The photoelectric conversion device according to configuration 11 or 12. (Configuration 14) In the plan view, the distance from the center of the first pixel to the second separation portion is substantially equal to the distance from the center of the second pixel to the second separation portion. 14. The photoelectric conversion device according to claim 13, (Configuration 15) A plurality of first pixels are arranged at substantially equal intervals in a first direction and in a second direction perpendicular to the first direction, a plurality of second pixels are arranged at substantially equal intervals in each of the first direction and the second direction; A plurality of second separation portions are disposed at substantially equal intervals in each of a third direction that equally bisects the first direction and the second direction and a fourth direction perpendicular to the third direction. 15. The photoelectric conversion device according to claim 13 or 14. (Configuration 16) In the plan view, a distance from a cathode electrode to an anode electrode of the first pixel is substantially equal to a distance from a cathode electrode to an anode electrode of the second pixel. 15. The photoelectric conversion device according to configuration 14. (Configuration 17) A plurality of first pixels are arranged at substantially equal intervals in a first direction and in a second direction perpendicular to the first direction, a plurality of second pixels are arranged at substantially equal intervals in each of the first direction and the second direction; A plurality of cathode electrodes corresponding to a plurality of pixels including the plurality of first pixels and the plurality of second pixels are arranged at substantially equal intervals in each of a third direction that bisects the first direction and the second direction and a fourth direction perpendicular to the third direction. 17. The photoelectric conversion device according to any one of configurations 11 to 16. (Configuration 18) The separation unit separates the plurality of pixels, In the plan view, The second pixel is disposed substantially at the center of four first pixels arranged in two rows and two columns, The separation portion surrounds the first pixel with a substantial octagon, and surrounds the second pixel with a substantial rectangle formed by four substantial octagons corresponding to the four first pixels, respectively. 18. The photoelectric conversion device according to claim 17, (Configuration 19) Further, the light receiving surface has a plurality of metal bondings on a side opposite to the light receiving surface, the metal bondings corresponding to the plurality of pixels, respectively. In the plan view, the positions of the metal bonds are substantially equal to the positions of the cathode electrodes. 19. The photoelectric conversion device according to configuration 17 or 18. (Configuration 20) The first pixel has a trench that is not provided in the second pixel. 20. The photoelectric conversion device according to any one of configurations 10 to 19. (Configuration 21) a first pixel including a first avalanche photodiode and a second pixel including a second avalanche photodiode; The first pixel has a trench that is not provided in the second pixel. A photoelectric conversion device comprising: (Configuration 22) The photoelectric conversion device according to any one of configurations 1 to 21, a signal processing unit that generates an image using a signal output from the photoelectric conversion device; A photoelectric conversion system comprising: (Configuration 23) A moving object including the photoelectric conversion device according to any one of configurations 1 to 21, A moving body comprising: a control unit that controls the movement of the moving body using a signal output from the photoelectric conversion device. (Configuration 24) The photoelectric conversion device according to any one of configurations 1 to 21, an optical device corresponding to the photoelectric conversion device; A control device for controlling the photoelectric conversion device; a processing device that processes a signal output from the photoelectric conversion device; a display device that displays information obtained by the photoelectric conversion device; a storage device that stores information obtained by the photoelectric conversion device; and a mechanical device that operates based on information obtained by the photoelectric conversion device; At least one of An apparatus comprising: [Explanation of symbols]

[0190] 601: High sensitivity pixel 602: Low sensitivity pixel 330: Separation section 900: Trench

Claims

1. a first pixel including a first avalanche photodiode; a second pixel including a second avalanche photodiode; a separation portion separating the first pixel and the second pixel; having In a plan view, a distance from a center of the first pixel to the separation portion is longer than a distance from a center of the second pixel to the separation portion. A photoelectric conversion device comprising:

2. the separation portion is a first separation portion that separates a region of the first pixel that is closer to the light incident surface from a region of the second pixel that is closer to the light incident surface, the photoelectric conversion device further includes a second isolation portion that isolates an area of ​​the first pixel farther from the light incident surface from an area of ​​the second pixel farther from the light incident surface, In the plan view, a distance from a center of the second pixel to the second isolation portion is longer than a distance from a center of the second pixel to the first isolation portion.

2. The photoelectric conversion device according to claim 1.

3. the separation portion is a first separation portion that separates a region of the first pixel that is closer to the light incident surface from a region of the second pixel that is closer to the light incident surface, the photoelectric conversion device further includes a second isolation portion that isolates an area of ​​the first pixel farther from the light incident surface from an area of ​​the second pixel farther from the light incident surface, In the plan view, a distance from a center of the first pixel to the second separation portion is substantially equal to a distance from a center of the second pixel to the second separation portion.

2. The photoelectric conversion device according to claim 1.

4. the first avalanche photodiode includes a first semiconductor region of a first conductivity type; the second avalanche photodiode includes a second semiconductor region of the first conductivity type; The photoelectric conversion device according to claim 1, characterized in that, in the planar view, the distance from the end of the first semiconductor region on the isolation portion side to the isolation portion is longer than the distance from the end of the second semiconductor region on the isolation portion side to the isolation portion.

5. A plurality of first pixels are arranged at substantially equal intervals in each of a first direction and a second direction perpendicular to the first direction, A plurality of second pixels are arranged at substantially equal intervals in each of the first direction and the second direction, A plurality of second separation portions are disposed at substantially equal intervals in each of a third direction that bisects the first direction and the second direction and a fourth direction perpendicular to the third direction.

3. The photoelectric conversion device according to claim 2.

6. In the plan view, a distance from a cathode electrode to an anode electrode of the first pixel is substantially equal to a distance from a cathode electrode to an anode electrode of the second pixel.

4. The photoelectric conversion device according to claim 3.

7. A plurality of cathode electrodes respectively corresponding to a plurality of pixels including the plurality of first pixels and the plurality of second pixels are disposed at substantially equal intervals in each of the third direction and the fourth direction.

6. The photoelectric conversion device according to claim 5.

8. The separation unit separates the plurality of pixels, In the plan view, The second pixel is disposed substantially at the center of four first pixels arranged in two rows and two columns, The separation portion surrounds the first pixel with a substantial octagon, and surrounds the second pixel with a substantial rectangle formed by four substantial octagons corresponding to the four first pixels, respectively.

8. The photoelectric conversion device according to claim 7.

9. Further, the light receiving surface has a plurality of metal bondings on a side opposite to the light receiving surface, the metal bondings corresponding to the plurality of pixels, respectively. In the plan view, the positions of the metal bonds are substantially equal to the positions of the cathode electrodes.

9. The photoelectric conversion device according to claim 8.

10. a first pixel including a first avalanche photodiode and a second pixel including a second avalanche photodiode; The light leakage from the first pixel to the second pixel is suppressed more strongly than the light leakage from the second pixel to the first pixel. A photoelectric conversion device comprising:

11. a separation portion separating the first pixel and the second pixel, In a plan view, a distance from a center of the first pixel to the separation portion is longer than a distance from a center of the second pixel to the separation portion. The photoelectric conversion device according to claim 10 .

12. the first avalanche photodiode includes a first semiconductor region of a first conductivity type; the second avalanche photodiode includes a second semiconductor region of the first conductivity type; The photoelectric conversion device according to claim 11, characterized in that, in the planar view, the distance from the end of the first semiconductor region on the isolation portion side to the isolation portion is longer than the distance from the end of the second semiconductor region on the isolation portion side to the isolation portion.

13. the separation portion is a first separation portion that separates a region of the first pixel that is closer to the light incident surface from a region of the second pixel that is closer to the light incident surface, the photoelectric conversion device further includes a second isolation portion that isolates an area of ​​the first pixel farther from the light incident surface from an area of ​​the second pixel farther from the light incident surface, In the plan view, a distance from a center of the second pixel to the second isolation portion is longer than a distance from a center of the second pixel to the first isolation portion. The photoelectric conversion device according to claim 11 .

14. In the plan view, a distance from a center of the first pixel to the second separation portion is substantially equal to a distance from a center of the second pixel to the second separation portion.

14. The photoelectric conversion device according to claim 13.

15. A plurality of first pixels are arranged at substantially equal intervals in each of a first direction and a second direction perpendicular to the first direction, A plurality of second pixels are arranged at substantially equal intervals in each of the first direction and the second direction, A plurality of second separation portions are disposed at substantially equal intervals in each of a third direction that bisects the first direction and the second direction and a fourth direction perpendicular to the third direction.

14. The photoelectric conversion device according to claim 13.

16. In the plan view, the distance from the cathode electrode to the anode electrode of the first pixel and the The distance from the cathode electrode to the anode electrode of the second pixel is approximately equal to 14. The photoelectric conversion device according to claim 13.

17. A plurality of first pixels are arranged at substantially equal intervals in each of a first direction and a second direction perpendicular to the first direction, A plurality of second pixels are arranged at substantially equal intervals in each of the first direction and the second direction, A plurality of cathode electrodes corresponding to a plurality of pixels including the plurality of first pixels and the plurality of second pixels are arranged at substantially equal intervals in each of a third direction that bisects the first direction and the second direction and a fourth direction perpendicular to the third direction. The photoelectric conversion device according to claim 11 .

18. The separation unit separates the plurality of pixels, In the plan view, The second pixel is disposed substantially at the center of four first pixels arranged in two rows and two columns, The separation portion surrounds the first pixel with a substantial octagon, and surrounds the second pixel with a substantial rectangle formed by four substantial octagons corresponding to the four first pixels, respectively.

18. The photoelectric conversion device according to claim 17.

19. Further, the light receiving surface has a plurality of metal bondings on a side opposite to the light receiving surface, the metal bondings corresponding to the plurality of pixels, respectively. In the plan view, the positions of the metal bonds are substantially equal to the positions of the cathode electrodes.

18. The photoelectric conversion device according to claim 17.

20. The first pixel is provided with a trench that is not provided in the second pixel. The photoelectric conversion device according to claim 10 .

21. a first pixel including a first avalanche photodiode and a second pixel including a second avalanche photodiode; The first pixel is provided with a trench that is not provided in the second pixel. A photoelectric conversion device comprising:

22. The photoelectric conversion device according to any one of claims 1 to 21, a signal processing unit that generates an image using a signal output from the photoelectric conversion device; A photoelectric conversion system comprising:

23. A moving object comprising the photoelectric conversion device according to any one of claims 1 to 21, A moving body comprising: a control unit that controls the movement of the moving body using a signal output from the photoelectric conversion device.

24. The photoelectric conversion device according to any one of claims 1 to 21, an optical device corresponding to the photoelectric conversion device; A control device for controlling the photoelectric conversion device; a processing device that processes a signal output from the photoelectric conversion device; a display device that displays information obtained by the photoelectric conversion device; a storage device that stores information obtained by the photoelectric conversion device; and a mechanical device that operates based on information obtained by the photoelectric conversion device; At least one of An apparatus comprising:

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