Photoelectric converter and photodetection system

Abstract

This invention provides a technology for increasing the placement area of ​​elements and circuits arranged in a semiconductor layer and improving the flexibility of layout in a photoelectric conversion device having through-electrodes that penetrate a semiconductor layer. [Solution] The photoelectric conversion device includes a first semiconductor layer on which an avalanche photodiode is provided, a second semiconductor layer arranged to overlap the first semiconductor layer in a plan view, a first insulating portion and a second insulating portion provided to penetrate the second semiconductor layer, a first through-electrode that penetrates the first insulating portion and is electrically connected to the first electrode of the avalanche photodiode, and a second through-electrode that penetrates the second insulating portion and is electrically connected to the second electrode of the avalanche photodiode. The first insulating portion and the second insulating portion are provided in the second semiconductor layer spaced apart from each other.

Description

Technical Field

[0001] The present invention relates to a photoelectric conversion device and a light detection system.

Background Art

[0002] Patent Document 1 describes a stacked image sensor configured by stacking a plurality of structures each including a semiconductor layer. In Patent Document 1, as one of the structures for electrically connecting between these plurality of structures, a through electrode provided so as to penetrate the semiconductor layer is shown.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, no particular consideration is given to the arrangement of the through electrode penetrating the semiconductor layer, and there is a possibility that the arrangement and layout of elements and circuits arranged in the semiconductor layer penetrated by the through electrode are restricted.

[0005] An object of the present invention is to provide a technique for increasing the layout area of elements and circuits arranged in a semiconductor layer and improving the degree of freedom of layout in a photoelectric conversion device having a through electrode penetrating the semiconductor layer.

Means for Solving the Problems

[0006] One disclosure of this specification provides a photoelectric conversion device comprising: a first semiconductor layer on which an avalanche photodiode is provided; a second semiconductor layer arranged to overlap the first semiconductor layer in a plan view; a first insulating portion and a second insulating portion provided to penetrate the second semiconductor layer; a first through-electrode penetrating the first insulating portion and electrically connected to the first electrode of the avalanche photodiode; and a second through-electrode penetrating the second insulating portion and electrically connected to the second electrode of the avalanche photodiode, wherein the first insulating portion and the second insulating portion are provided spaced apart from each other in the second semiconductor layer. [Effects of the Invention]

[0007] According to the present invention, in a photoelectric conversion device having through-electrodes penetrating a semiconductor layer, the area for arranging elements and circuits in the semiconductor layer can be increased, and the degree of freedom in layout can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a block diagram showing an example configuration of a photoelectric conversion device according to the first embodiment. [Figure 2] This is a block diagram showing another configuration example of the photoelectric conversion device according to the first embodiment. [Figure 3] This is a block diagram showing an example of the pixel configuration of a photoelectric converter according to the first embodiment. [Figure 4] This diagram illustrates the basic operation of the photoelectric conversion unit in the photoelectric conversion device according to the first embodiment. [Figure 5] This is a perspective view showing an example of the configuration of a photoelectric conversion device according to the first embodiment. [Figure 6] This is a plan view of a pixel in a photoelectric conversion device according to the first embodiment. [Figure 7] This is a cross-sectional view of a pixel in a photoelectric converter according to the first embodiment. [Figure 8] This is a plan view showing an example of the arrangement of the quench element and waveform shaping circuit in a photoelectric converter according to the first embodiment. [Figure 9]It is a plan view of a pixel in a photoelectric conversion device according to the second embodiment. [Figure 10] It is a cross-sectional view of a pixel in a photoelectric conversion device according to the second embodiment. [Figure 11] It is a plan view of a pixel in a photoelectric conversion device according to the third embodiment. [Figure 12] It is a cross-sectional view of a pixel in a photoelectric conversion device according to the third embodiment. [Figure 13] It is a plan view of a pixel in a photoelectric conversion device according to the fourth embodiment. [Figure 14] It is a cross-sectional view of a pixel in a photoelectric conversion device according to the fourth embodiment. [Figure 15] It is a plan view of a pixel in a photoelectric conversion device according to the fifth embodiment. [Figure 16] It is a cross-sectional view of a pixel in a photoelectric conversion device according to the fifth embodiment. [Figure 17] It is a plan view of a pixel in a photoelectric conversion device according to the sixth embodiment. [Figure 18] It is a cross-sectional view of a pixel in a photoelectric conversion device according to the sixth embodiment. [Figure 19] It is a plan view of a pixel in a photoelectric conversion device according to the seventh embodiment. [Figure 20] It is a cross-sectional view of a pixel in a photoelectric conversion device according to the seventh embodiment. [Figure 21] It is a plan view of a pixel in a photoelectric conversion device according to the eighth embodiment. [Figure 22] It is a cross-sectional view of a pixel in a photoelectric conversion device according to the eighth embodiment. [Figure 23] It is a plan view of a pixel in a photoelectric conversion device according to the ninth embodiment. [Figure 24] It is a cross-sectional view of a pixel in a photoelectric conversion device according to the ninth embodiment. [Figure 25] It is a plan view of a pixel in a photoelectric conversion device according to the tenth embodiment. [Figure 26] It is a cross-sectional view of a pixel in a photoelectric conversion device according to the tenth embodiment. [Figure 27]Cross-sectional view of a pixel in a photoelectric conversion device according to the 11th embodiment. [Figure 28] Cross-sectional view of a pixel in a photoelectric conversion device according to the 12th embodiment. [Figure 29] Planar view of a pixel in a photoelectric conversion device according to the 12th embodiment. [Figure 30] Block diagram showing a schematic configuration of a photodetection system according to the 13th embodiment. [Figure 31] Block diagram showing a schematic configuration of a distance image sensor according to the 14th embodiment. [Figure 32] Schematic diagram showing a configuration example of an endoscopic surgery system according to the 15th embodiment. [Figure 33] Schematic diagram showing a configuration example of a moving body according to the 16th embodiment. [Figure 34] Block diagram showing a schematic configuration of a photodetection system according to the 16th embodiment. [Figure 35] Flow chart showing the operation of a photodetection system according to the 16th embodiment. [Figure 36] Schematic diagram showing a schematic configuration of a photodetection system according to the 17th embodiment.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. In the following description, terms indicating a specific direction or position (for example, "up", "down", "right", "left", and other terms including those terms) are used as necessary. The use of those terms is for facilitating the understanding of the embodiments with reference to the drawings, and the technical scope of the present invention is not limited by the meanings of those terms. Also, the sizes and positional relationships of the members shown in each drawing may be exaggerated for clarity of explanation.

[0010] In the embodiments described below, the focus will be on photoelectric converters for imaging applications as examples of semiconductor devices. However, each embodiment is not limited to photoelectric converters for imaging applications and can be applied to other semiconductor devices. For example, other examples of semiconductor devices include distance measuring devices (devices for distance measurement using focus detection or TOF (Time of Flight)) and photometric devices (devices for measuring the amount of incident light).

[0011] [First Embodiment] The schematic configuration of the photoelectric conversion device according to the first embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a block diagram showing the schematic configuration of the photoelectric conversion device according to this embodiment.

[0012] As shown in Figure 1, the photoelectric conversion device 100 according to this embodiment includes a pixel area 10, a vertical scanning circuit section 40, a readout circuit section 50, a horizontal scanning circuit section 60, an output circuit section 70, and a control pulse generation section 80.

[0013] The pixel region 10 is provided with multiple pixels 12 arranged in an array such that they form multiple rows and multiple columns. Each pixel 12 may consist of a photoelectric conversion unit including a photoelectric conversion element and a signal processing unit that processes the signal output from the photoelectric conversion unit, as will be described later. The number of pixels 12 constituting the pixel region 10 is not particularly limited. For example, the pixel region 10 can be composed of multiple pixels 12 arranged in an array of several thousand rows x several thousand columns, as in a typical digital camera. Alternatively, the pixel region 10 may be composed of multiple pixels 12 arranged in one row or one column. Alternatively, the pixel region 10 may be composed of a single pixel 12.

[0014] Each row of the pixel array in the pixel region 10 has a control line 14 extending in a first direction (horizontal direction in Figure 1). The control line 14 is connected to each pixel 12 arranged in the first direction and forms a common signal line for these pixels 12. The first direction in which the control line 14 extends is sometimes called the row direction or horizontal direction. Each of the control lines 14 may include multiple signal lines for supplying multiple types of control signals to the pixels 12.

[0015] Furthermore, each column of the pixel array in the pixel region 10 has an output line 16 extending in a second direction (vertical direction in Figure 1) that intersects the first direction. The output line 16 is connected to each pixel 12 arranged in the second direction, forming a common signal line for these pixels 12. The second direction in which the output line 16 extends is sometimes called the column direction or the vertical direction. Each of the output lines 16 may contain multiple signal lines. For example, the output line 16 may contain multiple signal lines for transferring multi-bit digital signals output from the pixels 12 bit by bit.

[0016] Each row's control line 14 is connected to the vertical scanning circuit unit 40. The vertical scanning circuit unit 40 is a control circuit that receives control signals output from the control pulse generation unit 90, generates control signals to drive the pixels 12, and supplies them to the pixels 12 via the control lines 14. Logic circuits such as shift registers and address decoders may be used in the vertical scanning circuit unit 40. The vertical scanning circuit unit 40 sequentially scans the pixels 12 within the pixel area 10 row by row and outputs the pixel signal of each pixel 12 to the readout circuit unit 50 via the output line 16.

[0017] Each output line 16 of a column is connected to the readout circuit 50. The readout circuit 50 includes a plurality of holding units (not shown) corresponding to each column of the pixel array of the pixel region 10, and has the function of holding the pixel signals of the pixels 12 of each column, which are output row by row from the pixel region 10 via the output line 16, in the holding unit of the corresponding column.

[0018] The horizontal scanning circuit unit 60 is a control circuit that receives a control signal output from the control pulse generation unit 90, generates a control signal for reading pixel signals from the holding units of each column of the reading circuit unit 50, and supplies it to the reading circuit unit 50. Logic circuits such as shift registers and address decoders may be used in the horizontal scanning circuit unit 60. The horizontal scanning circuit unit 60 sequentially scans the holding units of each column of the reading circuit unit 50 and sequentially outputs the pixel signals held in each to the output circuit unit 70.

[0019] The output circuit section 70 has an external interface circuit and is a circuit section for outputting the pixel signal output from the readout circuit section 50 to the outside of the photoelectric converter 100. The external interface circuit provided by the output circuit section 70 is not particularly limited. For example, a SerDes (SERializer / DESerializer) transmission circuit can be applied as the external interface circuit. Examples of SerDes transmission circuits include an LVDS (Low Voltage Differential Signaling) circuit and an SLVS (Scalable Low Voltage Signaling) circuit. The output circuit section 70 may further have a signal processing circuit that performs predetermined digital signal processing on the pixel signal output from the readout circuit section 50, prior to the external interface circuit.

[0020] The control pulse generation unit 80 is a control circuit that generates control signals to control the operation and timing of the vertical scanning circuit unit 40, the readout circuit unit 50, and the horizontal scanning circuit unit 60, and supplies them to each functional block. At least a portion of the control signals that control the operation and timing of the vertical scanning circuit unit 40, the readout circuit unit 50, and the horizontal scanning circuit unit 60 may be supplied from outside the photoelectric converter 100.

[0021] Note that the connection configuration of each functional block of the photoelectric converter 100 is not limited to the configuration example shown in Figure 1, and can also be configured as shown in Figure 2, for example.

[0022] In the configuration example shown in Figure 2, output lines 16 extending in a first direction are provided for each row of the pixel array in the pixel region 10. Each output line 16 is connected to a pixel 12 aligned in the first direction, forming a common signal line for these pixels 12. Additionally, control lines 18 extending in a second direction are provided for each column of the pixel array in the pixel region 10. Each control line 18 is connected to a pixel 12 aligned in the second direction, forming a common signal line for these pixels 12.

[0023] Each row's control line 18 is connected to the horizontal scanning circuit unit 60. The horizontal scanning circuit unit 60 receives a control signal output from the control pulse generation unit 90, generates a control signal for reading pixel signals from the pixels 12, and supplies it to the pixels 12 via the control lines 18. Specifically, the horizontal scanning circuit unit 60 sequentially scans multiple pixels 12 in the pixel area 10 in column units and outputs the pixel signals of the pixels 12 in each row belonging to the selected column to the output line 16.

[0024] Each row's output line 16 is connected to the readout circuit unit 50. The readout circuit unit 50 includes a plurality of holding units (not shown) corresponding to each row of the pixel array in the pixel area 10, and has the function of holding the pixel signals of the pixels 12 of each row, which are output column by column from the pixel area 10 via the output line 16, in the holding unit of the corresponding row.

[0025] The readout circuit 50 receives a control signal output from the control pulse generation unit 90 and sequentially outputs the pixel signals held in the holding unit for each row to the output circuit 70. Other configurations in the example configuration shown in Figure 2 may be the same as those in the example configuration shown in Figure 1.

[0026] Figure 3 is a block diagram showing an example of the configuration of a pixel 12. Each pixel 12 has a photoelectric conversion unit 20 and a signal processing unit 30, as shown in Figure 3. The photoelectric conversion unit 20 has a photoelectric conversion element 22 and outputs a signal corresponding to the incident light. The signal processing unit 30 is a signal processing circuit that processes the signal output from the photoelectric conversion unit 20. The signal processing unit 30 may be configured to include, for example, a functional block 30A including a quench element 32 and a waveform shaping circuit 34, and a functional block 30B including a selection circuit 38 and a processing circuit 36. In the pixel configuration shown in Figure 3, the control lines 14 of each row may include a signal line 14A to which a control signal pRES is supplied from the vertical scanning circuit unit 40, and a signal line 14B to which a control signal pSEL is supplied from the vertical scanning circuit unit 40.

[0027] The photoelectric conversion element 22 may be an avalanche photodiode (hereinafter referred to as "APD"). The anode of the APD constituting the photoelectric conversion element 22 is connected to a node to which voltage VL is supplied. The cathode of the APD constituting the photoelectric conversion element 22 is connected to one terminal of the quench element 32. The connection node between the photoelectric conversion element 22 and the quench element 32 is the output node of the photoelectric conversion unit 20. The other terminal of the quench element 32 is connected to a node to which a voltage VH higher than voltage VL is supplied. Voltages VL and VH are set so that a reverse bias voltage sufficient for the APD to perform avalanche multiplication operation is applied. In one example, a negative high voltage is applied as voltage VL, and a positive voltage of about the power supply voltage is applied as voltage VH. For example, voltage VL is -30V and voltage VH is 1V.

[0028] The photoelectric conversion element 22 can be composed of an APD as described above. By supplying the APD with a reverse bias voltage sufficient for avalanche multiplication, the carriers generated by the incidence of light on the APD undergo avalanche multiplication, and an avalanche current is generated. There are two operating modes when a reverse bias voltage is supplied to the APD: Geiger mode and linear mode. Geiger mode is an operating mode in which the voltage applied between the anode and cathode is a reverse bias voltage greater than the breakdown voltage of the APD. Linear mode is an operating mode in which the voltage applied between the anode and cathode is a reverse bias voltage near or below the breakdown voltage of the APD. An APD operating in Geiger mode is called a SPAD (Single Photon Avalanche Diode). The APD constituting the photoelectric conversion element 22 may operate in linear mode or in Geiger mode, but a SPAD is more preferable because it has a larger potential difference than a linear mode APD and the effect of improving the signal-to-noise ratio is more pronounced.

[0029] In the circuit configuration shown in Figure 3, the anode of the APD is at a fixed potential and the signal is taken from the cathode side. However, the cathode of the APD may also be at a fixed potential and the signal may be taken from the anode side. In the former case, the signal charge is electrons. In the latter case, the signal charge is holes. Furthermore, this embodiment describes the case where one node of the APD is at a fixed potential, but the potentials of both nodes may fluctuate. The following description shows a configuration in which electrons are used as the signal charge. When holes are used as the signal charge, the conductivity type of the semiconductor regions constituting each part of the photoelectric conversion element 22 will be the opposite conductivity type to that of the configuration described below.

[0030] The quench element 32 has the function of converting the change in avalanche current generated in the photoelectric conversion element 22 into a voltage signal. Furthermore, the quench element 32 functions as a load circuit (quench circuit) during signal multiplication by avalanche multiplication, reducing the voltage applied to the photoelectric conversion element 22 and suppressing avalanche multiplication. This operation by the quench element 32 to suppress avalanche multiplication is called the quench operation. The quench element 32 also has the function of returning the voltage supplied to the photoelectric conversion element 22 to voltage VH by allowing current to flow to compensate for the voltage drop caused by the quench operation. This operation by the quench element 32 to return the voltage supplied to the photoelectric conversion element 22 to voltage VH is called the recharge operation. The quench element 32 can be composed of a resistor, a MOS transistor, or the like.

[0031] The waveform shaping circuit 34 has an input node to which the output signal from the photoelectric conversion unit 20 is supplied, and an output node. The waveform shaping circuit 34 has the function of converting the analog signal supplied from the photoelectric conversion unit 20 into a pulse signal. The waveform shaping circuit 34 may be composed of logic circuits including NOT gates (inverter circuits), NOR gates, NAND gates, etc. The output node of the waveform shaping circuit 34 is connected to the processing circuit 36.

[0032] The processing circuit 36 ​​has an input node to which the output signal of the waveform shaping circuit 34 is supplied, an input node connected to the control line 14, and an output node. The processing circuit 36 ​​has the function of performing predetermined signal processing on the output signal of the waveform shaping circuit 34 and holding the processed signal or processing result. The processing circuit 36 ​​is not particularly limited, but for example it may be a counter circuit. In this case, the processing circuit 36 ​​counts the pulses superimposed on the signal output from the waveform shaping circuit 34 and holds the count value which is the counting result. The signals supplied from the vertical scanning circuit unit 40 to the processing circuit 36 ​​via the control line 14 may include an enable signal for controlling the pulse counting period (exposure period) and a reset signal for resetting the count value held by the processing circuit 36. Figure 3 shows, as an example, a reset signal (control signal pRES) supplied via the signal line 14A. The output node of the processing circuit 36 ​​is connected to the selection circuit 38.

[0033] The selection circuit 38 has the function of switching the electrical connection state (connected or disconnected) between the processing circuit 36 ​​and the output line 16. The selection circuit 38 switches the connection state between the processing circuit 36 ​​and the output line 16 in accordance with the selection signal supplied from the vertical scanning circuit unit 40 via the control line 14 (in the configuration example of Figure 2, the selection signal supplied from the horizontal scanning circuit unit 60 via the control line 18). Figure 3 shows, as an example, the selection signal (control signal pSEL) supplied via the signal line 14B. The processing circuit 36 ​​may include a buffer circuit for outputting signals.

[0034] Pixel 12 is typically a unit structure that outputs a pixel signal for forming an image. However, in cases where the purpose is distance measurement using the TOF (Time of Flight) method, pixel 12 does not necessarily have to be a unit structure that outputs a pixel signal for forming an image. That is, pixel 12 can also be a unit structure that outputs a signal for measuring the time and amount of light that arrived.

[0035] Furthermore, the signal processing unit 30 does not necessarily need to be provided for each pixel 12; a single signal processing unit 30 may be provided for multiple pixels 12. In this case, a single signal processing unit 30 can be used to sequentially perform signal processing for multiple pixels 12.

[0036] Next, the basic operation of the photoelectric conversion unit 20 in the photoelectric conversion device according to this embodiment will be explained using Figure 4. Figure 4 is a diagram illustrating the basic operation of the photoelectric conversion element 22, the quench element 32, and the waveform shaping circuit 34 in the photoelectric conversion device according to this embodiment. Figure 4(a) is a circuit diagram of the photoelectric conversion element 22, the quench element 32, and the waveform shaping circuit 34. Figure 4(b) shows the waveform of the signal at the input node (node ​​A) of the waveform shaping circuit 34. Figure 4(c) shows the waveform of the signal at the output node (node ​​B) of the waveform shaping circuit 34. For the sake of simplicity, it is assumed here that the waveform shaping circuit 34 is configured as an inverter circuit.

[0037] At time t0, a reverse bias voltage with a potential difference equivalent to (VH-VL) is applied to the photoelectric element 22. A reverse bias voltage sufficient to cause avalanche multiplication is applied between the anode and cathode of the APD constituting the photoelectric element 22, but when no photons are incident on the photoelectric element 22, there are no carriers that serve as seeds for avalanche multiplication. Therefore, avalanche multiplication does not occur in the photoelectric element 22, and no current flows through the photoelectric element 22.

[0038] At the following time t1, assume that a photon is incident on the photoelectric conversion element 22. When a photon is incident on the photoelectric conversion element 22, electron-hole pairs are generated by photoelectric conversion, and avalanche multiplication occurs using these carriers as a seed, causing an avalanche multiplication current to flow through the photoelectric conversion element 22. This avalanche multiplication current flows through the quench element 32, causing a voltage drop across the quench element 32, and the voltage at node A begins to drop. When the voltage drop at node A becomes large and avalanche multiplication stops at time t3, the voltage level at node A will no longer drop.

[0039] When the avalanche multiplication in the photoelectric conversion element 22 stops, a current flows from the node to which voltage VL is supplied through the photoelectric conversion element 22 to node A to compensate for the voltage drop, and the voltage at node A gradually increases. Subsequently, at time t5, node A settles back to its original voltage level.

[0040] The waveform shaping circuit 34 binarizes the signal input from node A according to a predetermined threshold and outputs it from node B. Specifically, the waveform shaping circuit 34 outputs a low-level signal from node B when the voltage level at node A exceeds the threshold, and outputs a high-level signal from node B when the voltage level at node A is below the threshold. For example, as shown in Figure 4(b), suppose the voltage at node A is below the threshold during the period from time t2 to time t4. In this case, as shown in Figure 4(c), the signal level at node B is low during the period from time t0 to time t2 and from time t4 to time t5, and high during the period from time t2 to time t4.

[0041] Thus, the analog signal input from node A is waveform-shaped into a digital signal by the waveform shaping circuit 34. The pulse signal output from the waveform shaping circuit 34 in response to the incidence of photons on the photoelectric conversion element 22 is the photon detection pulse signal.

[0042] The photoelectric converter 100 of this embodiment may be configured as a stacked type photoelectric converter in which multiple substrates are stacked. For example, as shown in Figure 5, the photoelectric converter 100 may be configured by stacking three substrates, a sensor substrate 110, a circuit substrate 130, and a circuit substrate 160, and electrically connecting them to each other.

[0043] In the configuration example shown in Figure 5, at least the photoelectric conversion unit 20, one of the components of the pixel 12, can be placed on the sensor substrate 110. The functional block 30A of the signal processing unit 30, one of the components of the pixel 12, can be placed on the circuit board 130. The functional block 30B of the signal processing unit 30, one of the components of the pixel 12, can be placed on the circuit board 160. By placing the functional block 30A, which includes high-voltage elements, and the functional block 30B, which consists of logic circuits, on separate substrates, it becomes possible to manufacture each separately using an appropriate manufacturing process, and as a result, the performance of the photoelectric conversion device can be improved.

[0044] Each of the sensor substrate 110, circuit board 130, and circuit board 160 may be provided with a pixel region 10 that overlaps in a plan view. The photoelectric conversion unit 20, functional block 30A, and functional block 30B of each of the multiple pixels 12 constituting the pixel region 10 may be provided on the sensor substrate 110, circuit board 130, and circuit board 160, respectively, that overlap in a plan view. In this specification, a plan view means viewing from a direction perpendicular to the light incident surface of the sensor substrate 110. If the light incident surface of the semiconductor layer is rough when viewed microscopically, the plan view is defined based on the light incident surface of the semiconductor layer when viewed macroscopically. The photoelectric conversion unit 20 and the functional block 30A, and the functional block 30A and the functional block 30B may be electrically connected via connecting wiring (not shown) provided for each pixel 12.

[0045] Furthermore, the circuit boards 130 and 160 can be further equipped with a vertical scanning circuit section 40, a readout circuit section 50, a horizontal scanning circuit section 60, a DFE 70, a TX 80, and a control pulse generation section 90. The vertical scanning circuit section 40, the readout circuit section 50, the horizontal scanning circuit section 60, the DFE 70, the TX 80, and the control pulse generation section 90 can be arranged around the pixel area 10 on the circuit boards 130 and 160. Each of the vertical scanning circuit section 40, the readout circuit section 50, the horizontal scanning circuit section 60, the output circuit section 70, and the control pulse generation section 80 may be provided on one of the circuit boards 130 and 160, or they may be provided separately on the circuit boards 130 and 160.

[0046] By configuring a stacked photoelectric converter 100, the integration density of elements can be increased, and functionality can be enhanced. In particular, by arranging the photoelectric conversion unit 20 and the signal processing unit 30 on separate substrates, the photoelectric conversion elements 22 can be arranged at high density without sacrificing the light-receiving area of ​​the photoelectric conversion elements 22, thereby improving photon detection efficiency. Furthermore, by arranging the functional block 30A and functional block 30B of the signal processing unit 30 on separate substrates, the photoelectric conversion elements 22 can be arranged at high density while simultaneously achieving high integration and functionality of the processing circuit 36 ​​that constitutes the functional block 30B.

[0047] Although Figure 5 shows a configuration in which three substrates, sensor substrate 110, circuit substrate 130, and circuit substrate 160, are stacked, the circuits of circuit substrate 130 and circuit substrate 160 may be placed on a single substrate, resulting in a configuration of two substrates stacked. Alternatively, a configuration of four or more substrates stacked may be used.

[0048] Furthermore, while Figure 5 assumes chips diced as sensor substrate 110 and circuit boards 130, 160, the sensor substrate 110 and circuit boards 130, 160 are not limited to chips. For example, each of the sensor substrate 110 and circuit boards 130, 160 may be a wafer. Also, the sensor substrate 110 and circuit boards 130, 160 may be stacked in wafer form and then diced, or they may be made into chips and then stacked and bonded.

[0049] Next, the specific structure of the photoelectric conversion element 22 in the photoelectric conversion device 100 according to this embodiment will be described with reference to Figures 6 and 7. Figure 6 is a plan view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Figure 7 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment.

[0050] Figure 6 shows a plan view of four adjacent pixels 12 arranged in a 2x2 grid, which constitute a pixel region 10. The direction along the VII-VII' line in Figure 6 is the diagonal direction of the pixels 12. Figure 7 is a cross-sectional view of the plane perpendicular to the light incident plane containing the VII-VII' line in Figure 6. Figure 6(a) is a plan view of the plane parallel to the light incident plane containing the VIA-VIA' line in Figure 7, viewed from the side opposite to the light incident plane. Figure 6(b) is a plan view of the plane parallel to the light incident plane containing the VIB-VIB' line in Figure 7, viewed from the side opposite to the light incident plane.

[0051] Figure 7 shows an example of a photoelectric conversion device constructed by stacking three substrates: a sensor substrate 110, a circuit board 130, and a circuit board 160. The sensor substrate 110 has a semiconductor layer 111 having a first surface F11 and a second surface F12 opposite to the first surface, an insulating layer 121 provided on the side of the semiconductor layer 111 facing the first surface F11, and an optical structure layer 181 provided on the side of the semiconductor layer 111 facing the second surface F12. The circuit board 130 has a semiconductor layer 131 having a first surface F21 and a second surface F22 opposite to the first surface F21, a wiring structure layer 141 provided on the side of the semiconductor layer 131 facing the first surface F21, and an insulating layer 151 provided on the side of the semiconductor layer 131 facing the second surface F22. The circuit board 160 includes a semiconductor layer 161 having a first surface F31 and a second surface F32 opposite to the first surface F31, and a wiring structure layer 171 provided on the side of the semiconductor layer 161 facing the first surface F31.

[0052] The semiconductor layer 111 may be provided with at least one photoelectric conversion element 22 among the components of a plurality of pixels 12. Figure 7 shows two adjacent pixels 12 among the plurality of pixels 12 that constitute the pixel region 10. The photoelectric conversion element 22 is configured to receive a drive voltage from the side of the first surface F11 and to output a photon detection pulse signal to the side of the first surface F11. The photoelectric conversion element 22 is configured to detect light incident from the second surface F12, which is the back side of the semiconductor layer 111. In other words, the photoelectric conversion device of this embodiment is a so-called back-illuminated type photoelectric conversion device.

[0053] The structure of the photoelectric conversion element 22 is not particularly limited. Here, as an example, we assume that a charge-collecting SPAD including N-type semiconductor regions 112, 113, 115 and P-type semiconductor regions 114, 116, 117 is provided in a semiconductor layer 111 with a low impurity concentration.

[0054] The semiconductor layer 111 is a thinned semiconductor substrate, such as a single-crystal silicon substrate, and contains a predetermined concentration of N-type or P-type impurities. In this embodiment, as an example, a semiconductor layer 111 made by thinning an N-type silicon substrate with a low impurity concentration is assumed.

[0055] The P-type semiconductor region 117 is provided on the side of the second surface F12 of the semiconductor layer 111 in a cross-sectional view. In this specification, a cross-sectional view refers to viewing a cross section of the semiconductor layer perpendicular to the light incident surface from the normal direction. The P-type semiconductor region 117 is provided over the entire region where the photoelectric conversion element 22 is arranged, and overlaps with the N-type semiconductor regions 112, 113 and the P-type semiconductor regions 114, 115, 116 in a plan view. When configuring a back-illuminated photoelectric conversion device, it is preferable to arrange the P-type semiconductor region 117 so as to be in contact with the second surface F12. By configuring it in this way, the generation of dark current on the second surface F12 can be prevented. The P-type semiconductor region 116 is provided at the boundary portion of the photoelectric conversion element 22 of adjacent pixels 12. That is, in a plan view, the P-type semiconductor region 116 is provided so as to surround each of the regions where the photoelectric conversion element 22 is arranged. The P-type semiconductor region 116 is provided from the first surface F11 of the semiconductor layer 120 to the depth to which the P-type semiconductor region 117 is located. The portion of the P-type semiconductor region 116 that is in contact with the first surface F11 is a contact region with a high impurity concentration.

[0056] Inside the region enclosed by the P-type semiconductor regions 116 and 117, N-type semiconductor regions 112, 113, 115 and P-type semiconductor region 114 are provided. The N-type semiconductor region 112 is the region that constitutes the cathode of the APD and is provided on the side of the first surface F11 of the semiconductor layer 111, spaced apart from the P-type semiconductor region 116. The N-type semiconductor region 113 is provided so as to surround the periphery of the N-type semiconductor region 112. The P-type semiconductor region 114 is the region that constitutes the anode of the APD and is provided on the side of the second surface F12 than the N-type semiconductor regions 112 and 113. The P-type semiconductor region 114 is in contact with the P-type semiconductor region 116 at its peripheral edge in a plan view. The N-type semiconductor region 115 is provided between the P-type semiconductor region 114 and the P-type semiconductor region 117.

[0057] A pixel separation section 118 may be further provided inside the P-type semiconductor region 116. The pixel separation section 118 serves to prevent light from leaking into adjacent photoelectric conversion elements 22, and is preferably a wall-like structure surrounding each region where the photoelectric conversion elements 22 are arranged. The pixel separation section 118 can be constructed, for example, by embedding an insulating member or a metal member in a groove formed in the semiconductor layer 111. In the configuration example shown in Figure 7, the pixel separation section 118 is provided so as to extend from the first surface F11 to the second surface F12 of the semiconductor layer 111, but the pixel separation section 118 does not necessarily have to extend from the first surface F11 to the second surface F12.

[0058] The insulating layer 121 may be composed of a single insulating film or may be composed of multiple insulating films stacked together. For example, the insulating layer 121 may be composed of a stacked structure including an etching stopper film used when opening through holes into which the through electrodes 146 and 147, described later, are embedded.

[0059] The optical structure layer 181 may comprise, for example, a pinning film 182, a planarization layer 183, and a microlens layer containing a plurality of microlenses ML. The optical structure layer 181 may further include a filter layer (not shown). Various optical filters, such as color filters, infrared cut filters, and monochrome filters, can be applied to the filter layer.

[0060] The semiconductor layer 131 may be provided with elements that constitute the quench element 32 and the waveform shaping circuit 34 of the functional block 30A, which are components of a plurality of pixels 12. Figure 7 illustrates a transistor provided on the first surface F21 side of the semiconductor layer 131 as an example of the elements that constitute these functional blocks. In a plan view of the semiconductor layer 131, through holes extending from the first surface F21 to the second surface F22 are provided in the portion that overlaps with the N-type semiconductor region 112 and the P-type semiconductor region 116. By embedding an insulating material in these through holes, an insulating portion 132 is formed.

[0061] The wiring structure layer 141 may be composed of an insulating layer 142 and one or more wiring layers disposed within the insulating layer 142. These one or more wiring layers include a cathode wiring 143 electrically connected to the N-type semiconductor region 112, an anode wiring 144 electrically connected to the P-type semiconductor region 116, and wiring 145 composed of the uppermost wiring layer furthest from the first surface F21.

[0062] The semiconductor layer 161 may be provided with elements that constitute the selection circuit 38 and processing circuit 36 ​​of the functional block 30B, which are components of the multiple pixels 12. Figure 7 illustrates a transistor provided on the first surface F31 side of the semiconductor layer 161 as an example of the elements that constitute these functional blocks.

[0063] The wiring structure layer 171 may be composed of an insulating layer 172 and one or more wiring layers disposed within the insulating layer 172. These one or more wiring layers include wiring 173, which is composed of the uppermost wiring layer furthest from the first surface F31.

[0064] The sensor substrate 110 and the circuit board 130 are joined face-to-back such that the first surface F11 of the semiconductor layer 111, on which the insulating layer 121 is located, and the second surface F22 of the semiconductor layer 131, on which the insulating layer 151 is located, face each other. In other words, the joining surface J12 between the sensor substrate 110 and the circuit board 130 is formed by the interface between the insulating layer 121 and the insulating layer 151. The semiconductor layers 111 and 131 are arranged to overlap in a plan view. The electrical connection between the sensor substrate 110 and the circuit board 130 can be formed by through electrodes embedded in through holes penetrating the insulating layer 142, the insulating portion 132, and the insulating layer 121. For example, the cathode wiring 143 is electrically connected to the N-type semiconductor region 112 via a through electrode 146. Also, the anode wiring 144 is electrically connected to the P-type semiconductor region 116 via a through electrode 147.

[0065] Circuit boards 130 and 160 are joined face-to-face such that the first surface F21 of semiconductor layer 131 on which the wiring structure layer 141 is located faces the first surface F31 of semiconductor layer 161 on which the wiring structure layer 171 is located. In other words, the joining surface J23 between circuit boards 130 and 160 is formed by the interface between wiring structure layer 141 and wiring structure layer 171. The electrical connection between circuit boards 130 and 160 can be formed by a metal joint between the uppermost metal wiring (wiring 145) constituting the wiring structure layer 141 and the uppermost metal wiring (wiring 173) constituting the wiring structure layer 171.

[0066] As described above, the photoelectric conversion device of this embodiment is a so-called back-illuminated photoelectric conversion device that detects light incident from the second surface F12, which is the back surface side of the semiconductor layer 111, via the optical structural layer 181. However, the photoelectric conversion device according to the present invention may also be configured as a so-called front-illuminated photoelectric conversion device that detects light incident from the first surface F11, which is the front surface side of the semiconductor layer 111.

[0067] As described above, in the photoelectric conversion device of this embodiment, among the components of the pixel 12, the photoelectric conversion element 22 is arranged on the sensor substrate 110, and the quench element 32 and waveform shaping circuit 34 are arranged on the circuit board 130. The voltage VH is applied from the circuit board 130 side to the N-type semiconductor region 112, which is the cathode of the photoelectric conversion element 22, via the quench element 32, cathode wiring 143, and through electrode 146. The voltage VL is applied from the circuit board 130 side to the P-type semiconductor region 114, which is the anode of the photoelectric conversion element 22, via the anode wiring 144, through electrode 147, and P-type semiconductor region 116.

[0068] When joining a sensor substrate 110 and a circuit board 130 face-to-back such that the first surface F11 of the semiconductor layer 111 and the second surface F22 of the semiconductor layer 131 face each other, the through electrodes 146 and 147 are arranged to penetrate the semiconductor layer 131. In this case, to insulate the semiconductor layer 131 from the through electrodes 146 and 147, an insulating portion 132 is provided by making through holes in the part of the semiconductor layer 131 where the through electrodes 146 and 147 are arranged and embedding insulating material. The through electrodes 146 and 147 are then arranged to penetrate a region inside the outer periphery of the insulating portion 132 in a plan view. Therefore, the larger the area of ​​the insulating portion 132 in a plan view, the smaller the area of ​​the semiconductor layer 131 in a plan view becomes, and the circuit area of ​​the quench element 32 and waveform shaping circuit 34 placed on the semiconductor layer 131 is limited.

[0069] Therefore, in the photoelectric conversion device of this embodiment, the through electrode 146 electrically connected to the cathode of the photoelectric conversion element 22 and the through electrode 147 electrically connected to the anode of the photoelectric conversion element 22 are configured to pass through different insulating sections 132. By configuring it in this way, the area occupied by the insulating section 132 can be minimized, increasing the area for quenching element 32 and waveform shaping circuit 34, and improving the degree of freedom in placement. In addition, since the through electrode 146 and the through electrode 147 are placed in separate insulating sections 132, it is possible to suppress short circuits and dielectric breakdown between the through electrode 146 and the through electrode 147.

[0070] If the shape of the photoelectric conversion element 22 in a plan view is rectangular, then, for example, as shown in Figure 6(a), the insulating portion 132 where the through-electrode 146 is located can be positioned to overlap with the center of the rectangular shape. Similarly, the insulating portions 132 where the through-electrode 147 is located can be positioned to overlap with the corners of the rectangular shape. In this case, these five through-electrodes 146 and 147 can be arranged to penetrate different insulating portions 132. Furthermore, the insulating portions 132 where the through-electrodes 146 of adjacent pixels 12 are located are spaced apart from each other.

[0071] When the through electrodes 147 of adjacent photoelectric conversion elements 22 are placed in close proximity, these through electrodes 147 may be arranged to penetrate a single insulating portion 132. In the example shown in Figure 6(a), one insulating portion 132 is placed at the position where the corners of the four photoelectric conversion elements 22 overlap with adjacent portions, and each insulating portion 132 is penetrated by four through electrodes 147. This configuration makes it possible to reduce the area of ​​the insulating portion 132 compared to when an insulating portion 132 is placed for each through electrode 147. Furthermore, since the four through electrodes 147 arranged in one insulating portion 132 are controlled to the same potential, no problem will occur even if they are short-circuited.

[0072] Figure 8 is a plan view showing an example of the arrangement of the quench element 32 and the waveform shaping circuit 34 in the semiconductor layer 131. Figure 8 is a plan view of the plane parallel to the light incident plane, which includes the VIB-VIB' line in Figure 7, viewed from the side opposite to the light incident plane.

[0073] In the circuit diagram of Figure 3, the through-electrode 146 corresponds to the node where the cathode of the photoelectric conversion element 22 is connected to the quench element 32 and the waveform shaping circuit 34. In other words, the through-electrode 146 is connected to both the quench element 32 and the waveform shaping circuit 34 via wiring. Therefore, if the quench element 32 and the waveform shaping circuit 34 are placed far from the through-electrode 146, there is a concern that the wiring distance will increase and the parasitic capacitance of the cathode will increase, and the wiring layout may become complicated. For this reason, it is preferable to place the quench element 32 and the waveform shaping circuit 34 adjacent to the through-electrode 146, for example, as shown in Figure 8. By arranging the quench element 32 and the waveform shaping circuit 34 in this way, it is possible to reduce parasitic capacitance and improve layout efficiency.

[0074] In order to arrange the quench element 32 and the waveform shaping circuit 34 adjacent to the through-electrode 146, one of the quench element 32 and the waveform shaping circuit 34 can be repeatedly placed between the through-electrode 146 at a pixel pitch period in both the column and row directions.

[0075] In the arrangement example shown in Figure 8(a), the quench elements 32 and waveform shaping circuits 34 are alternately arranged between the through electrodes 146 in the column and row directions, respectively, at a pixel pitch period. As a result, the through electrodes 146 are positioned between the quench elements 32 and the waveform shaping circuits 34 in both the column and row directions. Consequently, the through electrodes 146 can be positioned adjacent to both the quench elements 32 and the waveform shaping circuits 334.

[0076] Furthermore, focusing on the through-electrode 147, in the arrangement example shown in Figure 8(a), a first row consisting of through-electrodes 147 surrounded on all four sides by quench elements 32 and a second row consisting of through-electrodes 147 surrounded on all four sides by waveform shaping circuits 34 are arranged alternately in the column direction. In the first row, through-electrodes 147 surrounded by four quench elements 32 and through-electrodes 147 surrounded by two quench elements 32 and two waveform shaping circuits 34 are arranged alternately. In the second row, through-electrodes 147 surrounded by four waveform shaping circuits 34 and through-electrodes 147 surrounded by two quench elements 32 and two waveform shaping circuits 34 are arranged alternately. The arrangement in the column direction is the same as in the row direction described above. When different types of elements are placed adjacent to each other, for example, when elements with different voltage ratings are placed adjacent to each other, more space may be required than when elements of the same type are placed adjacent to each other. Therefore, by arranging the quench element 32 and the waveform shaping circuit 34 together, it becomes possible to improve layout efficiency.

[0077] In the arrangement example shown in Figure 8(b), the quench elements 32 are arranged between the through electrodes 146 at a pixel pitch period in the column direction, and the waveform shaping circuits 34 are arranged between the through electrodes 146 at a pixel pitch period in the row direction. In addition, the waveform shaping circuits 34 are arranged between the through electrodes 147 at a pixel pitch period in the column direction, and the quench elements 32 are arranged between the through electrodes 147 at a pixel pitch period in the row direction. In this case, the quench elements 32 and the waveform shaping circuits 34 are translationally symmetric in the direction of arrangement, thus improving resistance to alignment variations.

[0078] Thus, in this embodiment, the insulating portion 132 through which the through electrode 146 electrically connected to the cathode of the photoelectric conversion element 22 passes and the insulating portion 132 through which the through electrode 147 electrically connected to the anode passes are provided spaced apart from each other. This reduces the area of ​​the insulating portion 132 in the semiconductor layer 131. Therefore, according to this embodiment, in a photoelectric conversion device having through electrodes that penetrate the semiconductor layer 131, the area of ​​elements and circuits arranged in the semiconductor layer can be increased, and the degree of freedom of layout can be improved.

[0079] [Second Embodiment] A photoelectric conversion device according to a second embodiment of the present invention will be described with reference to Figures 9 and 10. Figure 9 is a plan view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Figure 10 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Components similar to those in the photoelectric conversion device according to the first embodiment are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0080] Figure 9 shows a plan view of four adjacent pixels 12 arranged in a 2x2 grid, which constitute a pixel region 10. The direction along the XX' line in Figure 9 is the diagonal direction of the pixels 12. Figure 10 is a cross-sectional view of the plane perpendicular to the light incident plane containing the XX' line in Figure 9. Figure 9(a) is a plan view of the plane parallel to the light incident plane containing the IXA-IXA' line in Figure 10, viewed from the side opposite to the light incident plane. Figure 9(b) is a plan view of the plane parallel to the light incident plane containing the IXB-IXB' line in Figure 10, viewed from the side opposite to the light incident plane.

[0081] As shown in Figures 9 and 10, the photoelectric converter according to this embodiment differs from the first embodiment, which has four through-electrodes 147 for each pixel 12, in that it has only one through-electrode 147 for each pixel 12. Other aspects of the photoelectric converter according to this embodiment may be the same as those of the first embodiment.

[0082] In the photoelectric conversion device of this disclosure, there are two types of through electrodes connecting the photoelectric conversion element 22 and the functional block 30A: a through electrode 146 electrically connected to the cathode of the photoelectric conversion element 22 and a through electrode 147 electrically connected to the anode of the photoelectric conversion element 22. Therefore, at least one through electrode 147 is required for each photoelectric conversion element 22. That is, the insulating portion 132 on which the through electrode 147 is located only needs to be positioned at least at one location that coincides with the four corners of a rectangular shape in a plan view. By providing only the minimum necessary two through electrodes in one pixel 12, the area of ​​the insulating portion 132 arranged in the semiconductor layer 131 can be reduced, further increasing the area for quenching elements 32 and waveform shaping circuits 34, and further improving the freedom of arrangement.

[0083] In the arrangement example shown in Figure 9, the N-type semiconductor region 112, which is the cathode of the photoelectric conversion element 22, and the through-electrode 146 connected to it are positioned at the center of the photoelectric conversion element 22 in a plan view. However, they may also be positioned offset away from the through-electrode 147. By configuring it in this way, the distance between the power supply position to the anode and the power supply position to the cathode can be increased, mitigating the electric field and reducing the DCR caused by a strong electric field. Note that DCR (Dark Count Rate) refers to the rate at which noise signals (dark pulses) are generated when there is no incident light.

[0084] Thus, according to this embodiment, in a photoelectric conversion device having through electrodes penetrating the semiconductor layer 131, the area for arranging elements and circuits in the semiconductor layer can be increased, and the degree of freedom in layout can be improved.

[0085] [Third Embodiment] A photoelectric conversion device according to a third embodiment of the present invention will be described with reference to Figures 11 and 12. Figure 11 is a plan view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Figure 12 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Components similar to those in the photoelectric conversion device according to the first or second embodiment are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0086] Figure 11 shows a plan view of four adjacent pixels 12 arranged in a 2x2 grid, which constitute a pixel region 10. The direction along the XII-XII' line in Figure 11 is the diagonal direction of the pixels 12. Figure 12 is a cross-sectional view of the plane perpendicular to the light incident plane containing the XII-XII' line in Figure 11. Figure 11(a) is a plan view of the plane parallel to the light incident plane containing the XIA-XIA' line in Figure 12, viewed from the side opposite to the light incident plane. Figure 11(b) is a plan view of the plane parallel to the light incident plane containing the XIB-XIB' line in Figure 12, viewed from the side opposite to the light incident plane.

[0087] The photoelectric converter according to this embodiment differs from the first and second embodiments, which provide four or one through-electrode 147 per pixel 12, in that, as shown in Figures 11 and 12, it provides two through-electrodes 147 per pixel 12. Other aspects of the photoelectric converter according to this embodiment may be the same as those of the first embodiment.

[0088] By reducing the number of through-electrodes 147 placed in one pixel 12 from four in the first embodiment to two, the area of ​​the insulating portion 132 arranged in the semiconductor layer 131 can be reduced. This further increases the area available for the quench element 32 and the waveform shaping circuit 34, and further improves the degree of freedom in their arrangement.

[0089] Compared to the second embodiment, the area of ​​the insulating portion 132 arranged in the semiconductor layer 131 increases, but considering the discharge of charge generated during avalanche multiplication, it is desirable to provide multiple through electrodes 147 for one pixel 12. In this embodiment, by arranging two through electrodes 147 for one pixel 12, it is possible to secure the distance between contacts while maintaining the ability to discharge charge, which is advantageous when miniaturizing compared to the first embodiment in which four through electrodes 147 are arranged for one pixel 12.

[0090] Thus, according to this embodiment, in a photoelectric conversion device having through electrodes penetrating the semiconductor layer 131, the area for arranging elements and circuits in the semiconductor layer can be increased, and the degree of freedom in layout can be improved.

[0091] [Fourth Embodiment] A photoelectric conversion device according to a fourth embodiment of the present invention will be described with reference to Figures 13 and 14. Figure 13 is a plan view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Figure 14 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Components similar to those in the photoelectric conversion devices of the first to third embodiments are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0092] Figure 13 shows a plan view of four adjacent pixels 12 arranged in a 2x2 grid, which constitute a pixel region 10. The direction along the XIV-XIV' line in Figure 13 is the diagonal direction of the pixels 12. Figure 14 is a cross-sectional view of the plane perpendicular to the light incident plane containing the XIV-XIV' line in Figure 13. Figure 13(a) is a plan view of the plane parallel to the light incident plane containing the XIIIA-XIIIA' line in Figure 14, viewed from the side opposite to the light incident plane. Figure 13(b) is a plan view of the plane parallel to the light incident plane containing the XIIIB-XIIIB' line in Figure 14, viewed from the side opposite to the light incident plane.

[0093] The photoelectric converter according to this embodiment is the same as the second embodiment in that it has only one through-electrode 147 for each pixel 12, as shown in Figures 13 and 14, but the arrangement of the through-electrodes 147 differs from that of the second embodiment. Other aspects of the photoelectric converter according to this embodiment may be the same as those of the first embodiment.

[0094] In this embodiment, through electrodes 147 connected to four photoelectric conversion elements 22 arranged in a 2x2 grid are placed in a single insulating section 132 located at the corners adjacent to each other. This configuration allows for a smaller area of ​​insulating section 132 compared to the case where an insulating section 132 is placed for each through electrode 147. As a result, compared to the second embodiment, the area available for the quench element 32 and the waveform shaping circuit 34 can be further increased, and the degree of freedom in placement can be further improved.

[0095] Thus, according to this embodiment, in a photoelectric conversion device having through electrodes penetrating the semiconductor layer 131, the area for arranging elements and circuits in the semiconductor layer can be increased, and the degree of freedom in layout can be improved.

[0096] [Fifth Embodiment] A photoelectric conversion device according to a fifth embodiment of the present invention will be described with reference to Figures 15 and 16. Figure 15 is a plan view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Figure 16 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Components similar to those in the photoelectric conversion devices of the first to fourth embodiments are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0097] Figure 15 shows a plan view of four adjacent pixels 12 arranged in a 2x2 grid, which constitute a pixel region 10. The direction along the XVI-XVI' line in Figure 15 is the diagonal direction of the pixels 12. Figure 16 is a cross-sectional view of the plane perpendicular to the light incident plane containing the XVI-XVI' line in Figure 15. Figure 15(a) is a plan view of the plane parallel to the light incident plane containing the XVA-XVA' line in Figure 16, viewed from the side opposite to the light incident plane. Figure 15(b) is a plan view of the plane parallel to the light incident plane containing the XVB-XVB' line in Figure 16, viewed from the side opposite to the light incident plane.

[0098] As shown in Figures 15 and 16, the photoelectric converter according to this embodiment further has wiring 122 arranged on the first surface F11 of the semiconductor layer 111. Other aspects of the photoelectric converter according to this embodiment may be the same as those of the first embodiment.

[0099] The wiring 122 serves as a connection point that electrically connects the P-type semiconductor regions 116 of adjacent photoelectric conversion elements 22. The wiring 122 may be composed of, for example, a highly doped P-type polysilicon layer. In a plan view, the wiring 122 is provided at each of the adjacent corners of the four photoelectric conversion elements 22 so as to electrically connect to the P-type semiconductor regions 116 of these four photoelectric conversion elements 22. A through-electrode 147 is electrically connected to each of the wirings 122. In other words, the voltage VL supplied from the circuit board 130 side to the through-electrode 147 via the anode wiring 144 is applied to the P-type semiconductor regions 116 of the four photoelectric conversion elements 22 via the wiring 122.

[0100] This configuration allows for the connection of four through-electrodes 147 to one pixel 12, while reducing the overall number of through-electrodes 147. This reduces the area of ​​the insulating portion 132 arranged in the semiconductor layer 131. As a result, the area available for the quench element 32 and the waveform shaping circuit 34 can be further increased, and the degree of freedom in their arrangement can be further improved.

[0101] In this embodiment, four through-electrodes 147 are connected to one pixel 12, but the number of through-electrodes 147 connected to one pixel 12 can be changed as appropriate, for example, as in the third and fourth embodiments.

[0102] Thus, according to this embodiment, in a photoelectric conversion device having through electrodes penetrating the semiconductor layer 131, the area for arranging elements and circuits in the semiconductor layer can be increased, and the degree of freedom in layout can be improved.

[0103] [Sixth Embodiment] A photoelectric conversion device according to the sixth embodiment of the present invention will be described with reference to Figures 17 and 18. Figure 17 is a plan view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Figure 18 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Components similar to those in the photoelectric conversion devices of the first to fifth embodiments are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0104] Figure 17 shows a plan view of four adjacent pixels 12 arranged in a 2x2 grid, which constitute a pixel region 10. The direction along the XVIII-XVIII' line in Figure 17 is the diagonal direction of the pixels 12. Figure 18 is a cross-sectional view of the plane perpendicular to the light incident plane containing the XVIII-XVIII' line in Figure 17. Figure 17(a) is a plan view of the plane parallel to the light incident plane containing the XVIIA-XVIIA' line in Figure 18, viewed from the side opposite to the light incident plane. Figure 17(b) is a plan view of the plane parallel to the light incident plane containing the XVIIB-XVIIB' line in Figure 18, viewed from the side opposite to the light incident plane.

[0105] As shown in Figures 17 and 18, the photoelectric conversion device according to this embodiment does not have pixel separation sections 118 placed in the areas where the corners of the four photoelectric conversion elements 22 are adjacent in a plan view. The through-electrode 147 is electrically connected to the P-type semiconductor region 116 in the area where the pixel separation section 118 is not placed. Other aspects of the photoelectric conversion device according to this embodiment may be the same as those of the first embodiment.

[0106] By not placing pixel separation sections 118 at the corners of the four photoelectric conversion elements 22 adjacent to each other, the P-type semiconductor regions of these photoelectric conversion elements 22 are electrically connected to one another. In other words, the P-type semiconductor regions 116 in the areas where the pixel separation sections 118 are not placed serve as connection points that electrically connect the P-type semiconductor regions 116 of adjacent photoelectric conversion elements 22. Therefore, by connecting a through-electrode 147 to this area, a voltage VL can be supplied from one through-electrode 147 to the four photoelectric conversion elements 22 of the pixels 12.

[0107] This configuration allows a voltage VL to be supplied from a single through-electrode 147 to multiple pixels 12, thereby reducing the total number of through-electrodes 147 and narrowing the area of ​​the insulating portion 132 arranged in the semiconductor layer 131. This further increases the area available for the quench element 32 and the waveform shaping circuit 34, and further improves the flexibility of their arrangement.

[0108] In this embodiment, no pixel separation sections 118 are provided at the corners of the four photoelectric conversion elements 22 adjacent to each other in a plan view. However, the pixel separation sections 118 may be provided from a position deeper than the first surface F11 of the semiconductor layer 111 to the second surface F12. In this case as well, the P-type semiconductor regions 116 of adjacent photoelectric conversion elements 22 are electrically connected to each other in the vicinity of the first surface F11, so it is possible to obtain the same effects as in this embodiment without impairing the separation characteristics between pixels 12.

[0109] Furthermore, in this embodiment, one through-electrode 147 is connected to one pixel 12, but the number of through-electrodes 147 connected to one pixel 12 can be changed as appropriate, for example, as in the third to fifth embodiments.

[0110] Thus, according to this embodiment, in a photoelectric conversion device having through electrodes penetrating the semiconductor layer 131, the area for arranging elements and circuits in the semiconductor layer can be increased, and the degree of freedom in layout can be improved.

[0111] [Seventh Embodiment] A photoelectric conversion device according to the seventh embodiment of the present invention will be described with reference to Figures 19 and 20. Figure 19 is a plan view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Figure 20 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Components similar to those in the photoelectric conversion devices of the first to sixth embodiments are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0112] Figure 19 shows a plan view of one pixel 12 among multiple pixels 12 that make up the pixel region 10. The direction along the XX-XX' line in Figure 19 is the diagonal direction of pixel 12. Figure 20 is a cross-sectional view of a plane perpendicular to the light incident plane containing the XX-XX' line in Figure 19. Figure 19(a) is a plan view of a plane parallel to the light incident plane containing the XIXA-XIXA' line in Figure 20, viewed from the side opposite to the light incident plane. Figure 19(b) is a plan view of a plane parallel to the light incident plane containing the XIXB-XIXB' line in Figure 18, viewed from the side opposite to the light incident plane.

[0113] As shown in Figures 19(a) and 20, the photoelectric converter according to this embodiment further has a light diffusion structure 124 on the first surface F11 of the semiconductor layer 111. Other aspects of the photoelectric converter according to this embodiment may be the same as those of the first embodiment.

[0114] The light diffusion structure 124 has the role of scattering light incident on the first surface F11 from the second surface F12 side and suppressing light leaking onto the circuit board 130 side. The light diffusion structure 124 can be configured, for example, by a trench structure in which an insulator is embedded in a groove formed on the first surface F11 of the semiconductor layer 111. It is preferable that the light diffusion structure 124 is located on the first surface F11 in a portion that overlaps with the semiconductor region (excluding the insulating portion 132) of the semiconductor layer 131 in a plan view. The light diffusion structure 124 has the role of scattering light incident on the second surface F12 side of the semiconductor layer 111, and as long as it has the function of scattering light incident from the second surface F12, the pattern constituting the light diffusion structure 124 is not particularly limited.

[0115] In a structure having through-electrodes 146 and 147 that penetrate the semiconductor layer 131 and are connected to the semiconductor layer 111, it is difficult to place metal wiring within the insulating layer 121 from a thermal standpoint during manufacturing. Therefore, it is not possible to place an optical reflective layer within the insulating layer 121, which may result in a decrease in near-infrared sensitivity and optical crosstalk to adjacent pixels.

[0116] When light incident on the first surface F11 from the second surface F12 side leaks onto the circuit board 130 side, that light is reflected at the interface between the semiconductor layer 131 and the insulating layer 151, which are made of materials with different refractive indices. When the light reflected at the interface between the semiconductor layer 131 and the insulating layer 151 propagates to an adjacent pixel 12, it can be detected by the photoelectric conversion element 22 of that pixel 12, potentially causing optical crosstalk.

[0117] By providing a light diffusion structure 124 on the first surface F11 of the semiconductor layer 111, light incident on the first surface F11 from the side of the second surface F12 can be scattered and returned to the side of the second surface F12. This reduces the amount of light leaking onto the circuit board 130 and suppresses optical crosstalk to adjacent pixels. By placing the light diffusion structure 124 in the portion that overlaps with the semiconductor region of the semiconductor layer 131 in a plan view, optical crosstalk to adjacent pixels can be suppressed more effectively.

[0118] Scattering light incident on the first surface F11 from the second surface F12 and returning it to the second surface F12 reduces the amount of light leaking onto the circuit board 130, and also has the effect of extending the optical path length for photoelectric conversion, thereby improving sensitivity. This effect is particularly greater with long-wavelength light, such as near-infrared light, which requires a long optical path length for photoelectric conversion.

[0119] When the light-diffusing structure 124 is placed near the avalanche multiplication region, it is desirable to place it at a certain distance from the avalanche multiplication region. This is because placing the light-diffusing structure 124 near the avalanche multiplication region may increase the dark current component and thus increase the DCR. From this perspective, it is desirable to place the light-diffusing structure 124 in a region that does not overlap with the N-type semiconductor regions 112 and 113. By arranging the light-diffusing structure 124 in this way, the DCR can be reduced.

[0120] In this embodiment, an example is shown in which the light diffusion structure 124 is applied to the photoelectric conversion device of the first embodiment, but the light diffusion structure 124 can be applied to other embodiments in the same manner as in this embodiment.

[0121] Thus, according to this embodiment, the same effects as those of the first to seventh embodiments can be achieved, while also suppressing optical crosstalk to adjacent pixels and improving sensitivity.

[0122] [Eighth Embodiment] An eighth embodiment of the present invention, a photoelectric conversion device, will be described with reference to Figures 21 and 22. Figure 21 is a plan view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Figure 22 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Components similar to those in the photoelectric conversion devices of the first to seventh embodiments are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0123] Figure 21 shows a plan view of one pixel 12 among a plurality of pixels 12 that constitute the pixel region 10. The direction along the XXII-XXII′ line in Figure 21 is the diagonal direction of pixel 12. Figure 22 is a cross-sectional view of a plane perpendicular to the light incident plane containing the XXII-XXII′ line in Figure 21. Figure 21(a) is a plan view of a plane parallel to the light incident plane containing the XXIA-XXIA′ line in Figure 22, viewed from the side opposite to the light incident plane. Figure 21(b) is a plan view of a plane parallel to the light incident plane containing the XXIB-XXIB′ line in Figure 22, viewed from the side opposite to the light incident plane. Figure 21(c) is a plan view of a plane parallel to the light incident plane containing the XXIC-XXIC′ line in Figure 22, viewed from the side opposite to the light incident plane.

[0124] As shown in Figures 21(c) and 22, the photoelectric converter according to this embodiment further includes a light-reflecting structure 125 within the insulating layer 121. Other aspects of the photoelectric converter according to this embodiment may be the same as those of the first embodiment.

[0125] The light-reflecting structure 125 reflects light incident on the insulating layer 121 from the semiconductor layer 111 side and suppresses light leaking onto the circuit board 130 side. The light-reflecting structure 125 may be made of a dielectric material with a different refractive index from the insulating material constituting the insulating layer 121. The light-reflecting structure 125 does not necessarily have to be a single-layer structure, but may be a laminated structure in which multiple dielectric materials are stacked. Preferably, the light-reflecting structure 125 is located in a portion that overlaps with the semiconductor region (excluding the insulating portion 132) of the semiconductor layer 131 in a plan view.

[0126] As mentioned above, in a structure having through-electrodes 146 and 147 that penetrate the semiconductor layer 131 and are connected to the semiconductor layer 111, it is difficult to place metal wiring within the insulating layer 121, which may result in a decrease in near-infrared sensitivity and optical crosstalk to adjacent pixels.

[0127] By providing a light-reflecting structure 125 within the insulating layer 121, light incident on the insulating layer 121 from the semiconductor layer 111 side can be reflected back to the semiconductor layer 111 side. This reduces the amount of light leaking onto the circuit board 130 side and suppresses optical crosstalk to adjacent pixels. By placing the light-reflecting structure 125 in the portion that overlaps with the semiconductor region of the semiconductor layer 131 in a plan view, optical crosstalk to adjacent pixels can be suppressed more effectively.

[0128] Reflecting light incident on the insulating layer 121 from the semiconductor layer 111 back to the semiconductor layer 111 reduces light leakage to the circuit board 130 and also improves sensitivity by extending the optical path length for photoelectric conversion. This effect is particularly significant with long-wavelength light, such as near-infrared light, which requires a long optical path length for photoelectric conversion.

[0129] The light absorption rate in the light-reflecting structure 125 can be controlled by the constituent materials and layer structure of the light-reflecting structure 125. For example, by appropriately setting the layer structure of the light-reflecting structure 125, it is possible to suppress the light absorption rate to a lower level than that of a light-reflecting structure made of metal material, thereby improving sensitivity. Furthermore, since the wavelength at which the reflectivity is high can be controlled by the layer structure of the light-reflecting structure 125, a layer structure that increases the reflectivity for near-infrared wavelengths, where the penetration depth into silicon is long, may be applied.

[0130] As mentioned above, in the seventh embodiment, there is a concern that the dark current generation component will increase and the DCR will increase if the light diffusion structure 124 is placed near the avalanche multiplication region. However, in this embodiment, since trenches are not formed in the semiconductor layer 111, the same effects as in the seventh embodiment can be obtained without causing the increase in DCR that may occur in the seventh embodiment.

[0131] In this embodiment, the light-reflecting structure 125 is placed within the insulating layer 121 of the sensor substrate 110, but the light-reflecting structure 125 may also be placed within the insulating layer 151 of the circuit board 130.

[0132] Furthermore, although this embodiment shows an example in which the light reflection structure 125 is applied to the photoelectric conversion device of the first embodiment, the light reflection structure 125 can be applied to other embodiments in the same manner as in this embodiment.

[0133] Thus, according to this embodiment, the same effects as those of the first to seventh embodiments can be achieved, while also suppressing optical crosstalk to adjacent pixels and improving sensitivity.

[0134] [Ninth Embodiment] A photoelectric conversion device according to the ninth embodiment of the present invention will be described with reference to Figures 23 and 24. Figure 23 is a plan view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Figure 24 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Components similar to those in the photoelectric conversion devices of the first to eighth embodiments are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0135] Figure 23 shows a plan view of one pixel 12 among multiple pixels 12 that constitute a pixel region 10. The direction along the XXIV-XXIV′ line in Figure 23 is the diagonal direction of pixel 12. Figure 24 is a cross-sectional view of a plane perpendicular to the light incident plane containing the XXIV-XXIV′ line in Figure 23. Figure 23(a) is a plan view of a plane parallel to the light incident plane containing the XXIII-XXIIIA′ line in Figure 24, viewed from the side opposite to the light incident plane. Figure 23(b) is a plan view of a plane parallel to the light incident plane containing the XXIIIB-XXIIIB′ line in Figure 24, viewed from the side opposite to the light incident plane. Figure 23(c) is a plan view of a plane parallel to the light incident plane containing the XXIIIC-XXIIIC′ line in Figure 24, viewed from the side opposite to the light incident plane.

[0136] As shown in Figures 23(c) and 24, the photoelectric converter according to this embodiment further includes a light-absorbing structure 126 within the insulating layer 121. Other aspects of the photoelectric converter according to this embodiment may be the same as those of the first embodiment.

[0137] The light-absorbing structure 126 absorbs light incident on the insulating layer 121 from the semiconductor layer 111 side and suppresses light leaking onto the circuit board 130 side. The light-absorbing structure 126 may be made of a material capable of absorbing light in a wavelength range that overlaps with the detection wavelength range of the photoelectric conversion element 22. The light-absorbing structure 126 may be made of, for example, a polysilicon layer. It is preferable that the light-absorbing structure 126 is located in a portion that overlaps with the semiconductor region (excluding the insulating portion 132) of the semiconductor layer 131 in a plan view.

[0138] As mentioned above, in a structure having through-electrodes 146 and 147 that penetrate the semiconductor layer 131 and are connected to the semiconductor layer 111, it is difficult to place metal wiring within the insulating layer 121, which may cause optical crosstalk to adjacent pixels.

[0139] By providing a light-absorbing structure 126 within the insulating layer 121, light incident on the insulating layer 121 from the semiconductor layer 111 can be absorbed. This reduces the amount of light leaking onto the circuit board 130 and suppresses optical crosstalk to adjacent pixels. By placing the light-absorbing structure 126 in the portion that overlaps with the semiconductor region of the semiconductor layer 131 in a plan view, optical crosstalk to adjacent pixels can be suppressed more effectively.

[0140] As mentioned above, in the seventh embodiment, there is a concern that the dark current generation component will increase and the DCR will increase if the light diffusion structure 124 is placed near the avalanche multiplication region. However, in this embodiment, since trenches are not formed in the semiconductor layer 111, the same effects as in the seventh embodiment can be obtained without causing the increase in DCR that may occur in the seventh embodiment.

[0141] In this embodiment, the light-absorbing structure 126 is placed within the insulating layer 121 of the sensor substrate 110, but the light-absorbing structure 126 may also be placed within the insulating layer 151 of the circuit board 130.

[0142] Furthermore, although this embodiment shows an example in which the light absorption structure 126 is applied to the photoelectric conversion device of the first embodiment, the light absorption structure 126 can be applied to other embodiments in the same manner as in this embodiment.

[0143] Thus, according to this embodiment, the same effects as those of the first to seventh embodiments can be achieved, while also suppressing optical crosstalk to adjacent pixels and improving sensitivity.

[0144] [Tenth Embodiment] A photoelectric conversion device according to the tenth embodiment of the present invention will be described with reference to Figures 25 and 26. Figure 25 is a plan view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Figure 26 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Components similar to those in the photoelectric conversion devices of the first to ninth embodiments are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0145] Figures 25 and 26 show one pixel 12 among a plurality of pixels 12 that constitute a pixel region 10. The direction along the XXVI-XXVI′ line in Figure 25 is the diagonal direction of pixel 12. Figure 26 is a cross-sectional view of the plane perpendicular to the light incident plane containing the XXVI-XXVI′ line in Figure 25. Figure 25(a) is a plan view of the plane parallel to the light incident plane containing the XXVA-XXVA′ line in Figure 26, viewed from the side opposite to the light incident plane. Figure 25(b) is a plan view of the plane parallel to the light incident plane containing the XXVB-XXVB′ line in Figure 24, viewed from the side opposite to the light incident plane. Figure 25(c) is a plan view of the plane parallel to the light incident plane containing the XXVC-XXVC′ line in Figure 24, viewed from the side opposite to the light incident plane.

[0146] As shown in Figures 25(c) and 26, the photoelectric converter according to this embodiment further includes a light-diffusing structure 127 within the insulating layer 121. Other aspects of the photoelectric converter according to this embodiment may be the same as those of the first embodiment.

[0147] The light diffusion structure 127 plays a role in scattering light incident on the insulating layer 121 from the semiconductor layer 111 side and suppressing light leaking onto the circuit board 130 side. The light diffusion structure 127 can be constructed, for example, by arranging a plurality of structures made of dielectric materials with different refractive indices from the insulating material constituting the insulating layer 121 in a two-dimensional manner in a plan view. It is preferable that the light diffusion structure 127 is located in a portion that overlaps with the semiconductor region (excluding the insulating portion 132) of the semiconductor layer 131 in a plan view. The light diffusion structure 127 plays a role in scattering light incident on the insulating layer 121 from the semiconductor layer 111 side, and the pattern constituting the light diffusion structure 127 is not particularly limited as long as it has the function of scattering light incident on the semiconductor layer 111 side.

[0148] By providing a light diffusion structure 127 within the insulating layer 121, light incident on the insulating layer 121 from the semiconductor layer 111 side can be scattered and returned to the semiconductor layer 111 side. This reduces the amount of light leaking onto the circuit board 130 side and suppresses optical crosstalk to adjacent pixels. By placing the light diffusion structure 127 in the portion that overlaps with the semiconductor region of the semiconductor layer 131 in a plan view, optical crosstalk to adjacent pixels can be suppressed more effectively.

[0149] Scattering light incident on the insulating layer 121 from the semiconductor layer 111 and returning it to the semiconductor layer 111 has the effect of reducing light leaking onto the circuit board 130, as well as extending the optical path length for photoelectric conversion and improving sensitivity. This effect is particularly greater with long-wavelength light, such as near-infrared light, which requires a long optical path length for photoelectric conversion.

[0150] As mentioned above, in the seventh embodiment, there is a concern that the dark current generation component will increase and the DCR will increase if the light diffusion structure 124 is placed near the avalanche multiplication region. However, in this embodiment, since trenches are not formed in the semiconductor layer 111, the same effects as in the seventh embodiment can be obtained without causing the increase in DCR that may occur in the seventh embodiment.

[0151] In this embodiment, the light diffusion structure 127 is placed within the insulating layer 121 of the sensor substrate 110, but the light diffusion structure 127 may also be placed within the insulating layer 151 of the circuit board 130.

[0152] Furthermore, although this embodiment shows an example in which the light diffusion structure 127 is applied to the photoelectric conversion device of the first embodiment, the light diffusion structure 127 can be applied to other embodiments in the same manner as in this embodiment.

[0153] Thus, according to this embodiment, the same effects as those of the first to seventh embodiments can be achieved, while also suppressing optical crosstalk to adjacent pixels and improving sensitivity.

[0154] [Embodiment No. 11] A photoelectric conversion device according to the eleventh embodiment of the present invention will be described with reference to Figure 27. Figure 27 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment, and shows a diagonal cross-section of one pixel. Components similar to those in the photoelectric conversion devices of the first to tenth embodiments are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0155] As shown in Figure 27, the photoelectric converter according to this embodiment further has a scattering diffraction structure 128 provided on the second surface F12 of the semiconductor layer 111, compared to the photoelectric converter according to the seventh embodiment. Other aspects of the photoelectric converter according to this embodiment may be the same as those of the seventh embodiment.

[0156] The scattering and diffraction structure 128 plays a role in scattering and diffracting the light incident on the semiconductor layer 111. By providing the scattering and diffraction structure 128 on the second surface F12 of the semiconductor layer 111, the angle of incidence of light to the semiconductor layer 111 can be increased, extending the optical path length within the photoelectric conversion element 22 and improving sensitivity.

[0157] The scattering diffraction structure 128 can be constructed, for example, by embedding an insulating material in an inverted pyramidal or rectangular trench formed on the second surface F12 of the semiconductor layer 111. The pattern constituting the scattering diffraction structure 128 is not particularly limited, as long as it has the function of scattering and diffracting light incident from the second surface F12. It is desirable that the scattering diffraction structure 128 be provided in a region shallower than the P-type semiconductor region 117 when viewed from the side of the second surface F12.

[0158] In this embodiment, an example is shown in which the scattering diffraction structure 128 is applied to the photoelectric conversion device of the seventh embodiment. However, the scattering diffraction structure 128 can be applied to other embodiments in the same manner as in this embodiment.

[0159] Thus, according to this embodiment, the same effects as those of the first to seventh embodiments can be achieved, while also suppressing optical crosstalk to adjacent pixels and improving sensitivity.

[0160] [Twelfth Embodiment] A photoelectric conversion device according to the twelfth embodiment of the present invention will be described with reference to Figures 28 and 29. Figure 28 is a schematic cross-sectional view showing the structure of a pixel in the photoelectric conversion device according to this embodiment, showing a diagonal cross-section of one pixel. Figure 29 is a plan view showing the structure of a pixel in the photoelectric conversion device according to this embodiment. Components similar to those in the photoelectric conversion devices of the first to eleventh embodiments are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0161] Figures 28 and 29 show one of several pixels 12 that make up the pixel region 10. The direction along the XXVIII-XXVIII' line in Figure 29 is the diagonal direction of pixel 12. Figure 28 is a cross-sectional view of a plane perpendicular to the light incident plane containing the XXVIII-XXVIII' line in Figure 29. Figure 29 is a plan view of a plane parallel to the light incident plane containing the XXIX-XXIX' line in Figure 28, viewed from the side of the light incident plane.

[0162] As shown in Figure 28, the photoelectric converter according to this embodiment has a microlens array containing two or more microlenses ML for each pixel 12. Specifically, four microlenses ML are arranged for each pixel 12. These four microlenses ML are arranged in a 2x2 matrix in a plan view, as shown in Figure 29.

[0163] By arranging multiple microlenses ML for a single photoelectric conversion element 22, the angle of incidence of light to the semiconductor layer 111 can be increased, similar to the 11th embodiment, thereby extending the optical path length within the photoelectric conversion element 22. Furthermore, by further arranging the scattering diffraction structure 128, the scattering effect on the second surface F12 side can be further enhanced, further extending the optical path length within the photoelectric conversion element 22. This improves the sensitivity of the photoelectric conversion element 22.

[0164] In this embodiment, an example was shown in which multiple microlenses ML are applied to a single pixel 12 in the photoelectric conversion device of the 11th embodiment, but the same configuration as this embodiment can be applied to other embodiments as well.

[0165] Thus, according to this embodiment, the same effects as those of the first to seventh embodiments can be achieved, while also suppressing optical crosstalk to adjacent pixels and improving sensitivity.

[0166] [13th Embodiment] A photodetection system according to the thirteenth embodiment of the present invention will be described with reference to Figure 30. Figure 30 is a block diagram showing the schematic configuration of the photodetection system according to this embodiment. In this embodiment, a photodetection sensor to which the photoelectric converter 100 described in the first to twelfth embodiments is applied will be described.

[0167] The photoelectric converter 100 described in the first to twelfth embodiments above is applicable to various light detection systems. Examples of applicable light detection systems include imaging systems such as digital still cameras, digital camcorders, surveillance cameras, photocopiers, fax machines, mobile phones, in-vehicle cameras, and observation satellites. Camera modules, which include optical systems such as lenses and imaging devices, are also included in light detection systems. Figure 30 shows a block diagram of a digital still camera as an example of these.

[0168] The photodetection system 200 illustrated in Figure 30 includes a photoelectric converter 201, a lens 202 that forms an optical image of a subject onto the photoelectric converter 201, an aperture 204 for varying the amount of light passing through the lens 202, and a barrier 206 for protecting the lens 202. The lens 202 and the aperture 204 form an optical system that focuses light onto the photoelectric converter 201. The photoelectric converter 201 is the photoelectric converter 100 described in the first to twelfth embodiments, which converts the optical image formed by the lens 202 into image data.

[0169] The photodetection system 200 also includes a signal processing unit 208 that processes the output signal from the photoelectric converter 201. The signal processing unit 208 generates image data from the digital signal output by the photoelectric converter 201. The signal processing unit 208 also performs various corrections and compressions as needed before outputting the image data. The photoelectric converter 201 may include an AD conversion unit that generates the digital signal processed by the signal processing unit 208. The AD conversion unit may be formed on the semiconductor layer (semiconductor substrate) on which the photon detection element of the photoelectric converter 201 is formed, or on a semiconductor substrate separate from the semiconductor layer on which the photon detection element of the photoelectric converter 201 is formed. The signal processing unit 208 may also be formed on the same semiconductor layer as the photoelectric converter 201.

[0170] The light detection system 200 further includes a memory unit 210 for temporarily storing image data, and an external interface unit (external I / F unit) 212 for communicating with an external computer or the like. Furthermore, the light detection system 200 includes a recording medium 214 such as a semiconductor memory for recording or reading imaging data, and a recording medium control interface unit (recording medium control I / F unit) 216 for recording or reading data from the recording medium 214. The recording medium 214 may be built into the light detection system 200 or it may be detachable. In addition, communication between the recording medium control I / F unit 216 and the recording medium 214, and communication from the external I / F unit 212, may be performed wirelessly.

[0171] Furthermore, the photodetection system 200 includes an overall control / calculation unit 218 that controls various calculations and the entire digital still camera, and a timing generation unit 220 that outputs various timing signals to the photoelectric converter 201 and the signal processing unit 208. Here, the timing signals and the like may be input from an external source, and the photodetection system 200 only needs to have at least the photoelectric converter 201 and the signal processing unit 208 that processes the output signals output from the photoelectric converter 201. The timing generation unit 220 may be mounted on the photoelectric converter 201. In addition, the overall control / calculation unit 218 and the timing generation unit 220 may be configured to perform some or all of the control functions of the photoelectric converter 201.

[0172] The photoelectric converter 201 outputs the imaging signal to the signal processing unit 208. The signal processing unit 208 performs predetermined signal processing on the imaging signal output from the photoelectric converter 201 and outputs image data. The signal processing unit 208 generates an image using the imaging signal. The signal processing unit 208 may also be configured to perform distance measurement calculations on the signal output from the photoelectric converter 201.

[0173] Thus, according to this embodiment, by configuring a photodetection system using the photoelectric conversion device of the first to twelfth embodiments, a photodetection system capable of acquiring higher quality images can be realized.

[0174] [14th Embodiment] A distance image sensor according to the 14th embodiment of the present invention will be described with reference to Figure 31. Figure 31 is a block diagram showing the schematic configuration of the distance image sensor according to this embodiment. In this embodiment, the distance image sensor will be described as an example of a photodetection system to which the photoelectric conversion device 100 described in the first to 12th embodiments is applied.

[0175] As shown in Figure 31, the distance image sensor 300 according to this embodiment may be configured to include an optical system 302, a photoelectric converter 304, an image processing circuit 306, a monitor 308, and a memory 310. This distance image sensor 300 receives light (modulated light or pulsed light) that is irradiated from a light source device 320 toward the subject 330 and reflected from the surface of the subject 330, and acquires a distance image corresponding to the distance to the subject 330.

[0176] The optical system 302 consists of one or more lenses and has the role of forming an image of the image light (incident light) from the subject 330 onto the light-receiving surface (sensor part) of the photoelectric converter 304.

[0177] The photoelectric converter 304 is the photoelectric converter 100 described in the first to twelfth embodiments, and has the function of generating a distance signal indicating the distance to the subject 330 based on the image light from the subject 330, and supplying the generated distance signal to the image processing circuit 306.

[0178] The image processing circuit 306 has the function of performing image processing to construct a distance image based on the distance signal supplied from the photoelectric converter 304.

[0179] The monitor 308 has the function of displaying the distance image (image data) obtained by the image processing in the image processing circuit 306. The memory 310 also has the function of storing (recording) the distance image (image data) obtained by the image processing in the image processing circuit 306.

[0180] Thus, according to this embodiment, by configuring a distance image sensor using the photoelectric conversion device of the first to twelfth embodiments, it is possible to realize a distance image sensor capable of acquiring distance images containing more accurate distance information, in conjunction with improving the characteristics of the pixel 12.

[0181] [15th Embodiment] An endoscopic surgical system according to the 15th embodiment of the present invention will be described with reference to Figure 32. Figure 32 is a schematic diagram showing an example of the configuration of the endoscopic surgical system according to this embodiment. In this embodiment, the endoscopic surgical system will be described as an example of a photodetection system to which the photoelectric converter 100 described in the first to 12th embodiments is applied.

[0182] Figure 32 illustrates a surgeon (physician) 460 performing surgery on a patient 472 on a patient bed 470 using an endoscopic surgical system 400.

[0183] As shown in Figure 32, the endoscopic surgical system 400 of this embodiment may consist of an endoscope 410, surgical instruments 420, and a cart 430 equipped with various devices for endoscopic surgery. The cart 430 may be equipped with a Camera Control Unit (CCU) 432, a light source device 434, an input device 436, a treatment instrument control device 438, a display device 440, and the like.

[0184] The endoscope 410 comprises a barrel 412, the portion of which a predetermined length from the tip is inserted into the body cavity of the patient 472, and a camera head 414 connected to the base end of the barrel 412. Figure 32 illustrates the endoscope 410 configured as a so-called rigid endoscope having a rigid barrel 412, but the endoscope 410 may also be configured as a so-called flexible endoscope having a flexible barrel. The endoscope 410 is held in a movable state by an arm 416.

[0185] An opening into which an objective lens is fitted is provided at the tip of the endoscope tube 412. A light source device 434 is connected to the endoscope 410, and the light generated by the light source device 434 is guided to the tip of the endoscope tube by a light guide extending inside the endoscope tube 412, and is irradiated through the objective lens towards the object to be observed inside the body cavity of the patient 472. The endoscope 410 may be a straight-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0186] The camera head 414 contains an optical system and a photoelectric converter (not shown), and reflected light from the object being observed (observation light) is focused by the optical system into the photoelectric converter. The photoelectric converter converts the observation light into electrical signals, generating an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The photoelectric converter 100 described in the first to twelfth embodiments can be used as the photoelectric converter. The image signal is transmitted to the CCU 432 as RAW data.

[0187] The CCU432 consists of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and other components, and comprehensively controls the operation of the endoscope 410 and the display device 440. Furthermore, the CCU432 receives an image signal from the camera head 414 and performs various image processing operations on that image signal, such as development processing (demosaic processing), to display the image based on that image signal.

[0188] The display device 440 displays an image based on an image signal that has been processed by the CCU 432, under control from the CCU 432.

[0189] The light source device 434 consists of a light source such as an LED (Light Emitting Diode) and supplies illumination light to the endoscope 410 when photographing the surgical area, etc.

[0190] The input device 436 is an input interface for the endoscopic surgical system 400. The user can input various types of information and instructions to the endoscopic surgical system 400 via the input device 436.

[0191] The treatment instrument control device 438 controls the driving of the energy treatment instrument 450 for purposes such as tissue cauterization, incision, or blood vessel sealing.

[0192] The light source device 434 that supplies illumination light to the endoscope 410 when photographing the surgical area can be composed of, for example, an LED, a laser light source, or a combination thereof. 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 the white balance of the captured image can be adjusted in the light source device 434. In this case, it is also possible to capture images corresponding to each of the RGB colors in time-division by irradiating the observation target with laser light from each of the RGB laser light sources in time-division and controlling the drive of the image sensor of the camera head 414 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter on the image sensor.

[0193] Furthermore, the light source device 434 may be controlled to change the intensity of the light it outputs at predetermined time intervals. By controlling the drive of the image sensor of the camera head 414 in synchronization with the timing of the change in light intensity, images can be acquired in time-division order, and these images can be combined to generate high dynamic range images without so-called black crushing and white clipping.

[0194] Furthermore, the light source device 434 may be configured to supply light in a predetermined wavelength band corresponding to special light observation. In special light observation, for example, the wavelength dependence of light absorption in body tissue is utilized. Specifically, by irradiating with narrowband light compared to the irradiation light used during normal observation (i.e., white light), predetermined tissues such as blood vessels on the surface of mucosa can be imaged with high contrast. Alternatively, in special light observation, fluorescence observation may be performed to obtain an image from fluorescence generated by irradiation with excitation light. In fluorescence observation, excitation light can be irradiated onto body tissue and fluorescence from the body tissue can be observed, or a reagent such as indocyanine green (ICG) can be injected into body tissue and excitation light corresponding to the fluorescence wavelength of the reagent can be irradiated onto the body tissue to obtain a fluorescence image. The light source device 434 may be configured to supply narrowband light and / or excitation light corresponding to such special light observation.

[0195] Thus, according to this embodiment, by configuring an endoscopic surgical system using the photoelectric conversion device of the first to twelfth embodiments, an endoscopic surgical system capable of acquiring higher quality images can be realized.

[0196] [16th Embodiment] A photodetection system and mobile body according to the 16th embodiment of the present invention will be described with reference to Figures 33 to 35. Figure 33 is a schematic diagram showing an example of the configuration of a mobile body according to this embodiment. Figure 34 is a block diagram showing a schematic configuration of the photodetection system according to this embodiment. Figure 35 is a flowchart showing the operation of the photodetection system according to this embodiment. In this embodiment, an example of application to an in-vehicle camera is shown as a photodetection system to which the photoelectric converter 100 described in the first to 12th embodiments is applied.

[0197] Figure 33 is a schematic diagram showing an example of the configuration of a mobile body (vehicle system) according to this embodiment. Figure 33 shows the configuration of a vehicle 500 (automobile) as an example of a vehicle system incorporating a photodetection system to which a photoelectric converter according to the first to twelfth embodiments is applied. Figure 33(a) is a schematic front view of the vehicle 500, Figure 33(b) is a schematic top view of the vehicle 500, and Figure 33(c) is a schematic rear view of the vehicle 500. The vehicle 500 is equipped with a pair of photoelectric converters 502 on its front. Here, the photoelectric converters 502 are the photoelectric converters 100 described in the first to twelfth embodiments. The vehicle 500 also includes an integrated circuit 503, an alarm device 512, and a main control unit 513.

[0198] Figure 34 is a block diagram showing an example configuration of a photodetection system 501 mounted on a vehicle 500. The photodetection system 501 includes a photoelectric converter 502, an image preprocessing unit 515, an integrated circuit 503, and an optical system 514. The photoelectric converter 502 is the photoelectric converter 100 described in the first to twelfth embodiments. The optical system 514 forms an optical image of the subject on the photoelectric converter 502. The photoelectric converter 502 converts the optical image of the subject formed by the optical system 514 into an electrical signal. The image preprocessing unit 515 performs predetermined signal processing on the signal output from the photoelectric converter 502. The functions of the image preprocessing unit 515 may be incorporated into the photoelectric converter 502. The photodetection system 501 is provided with at least two sets of the optical system 514, photoelectric converter 502, and image preprocessing unit 515, and the output from the image preprocessing unit 515 of each set is input to the integrated circuit 503.

[0199] The integrated circuit 503 is an integrated circuit for imaging system applications and includes an image processing unit 504, an optical distance measuring unit 506, a disparity calculation unit 507, an object recognition unit 508, and an anomaly detection unit 509. The image processing unit 504 processes the image signal output from the image preprocessing unit 515. For example, the image processing unit 504 performs image processing such as development and defect correction on the output signal from the image preprocessing unit 515. The image processing unit 504 includes a memory 505 for temporarily holding the image signal. The memory 505 may store, for example, the location of known defective pixels in the photoelectric converter 502.

[0200] The optical distance measuring unit 506 focuses on and measures the distance of the subject. The parallax calculation unit 507 calculates distance information from multiple image data (parallax images) acquired by multiple photoelectric converters 502. Each of the photoelectric converters 502 may be configured to acquire various information such as distance information. The object recognition unit 508 recognizes subjects such as cars, roads, signs, and people. When the anomaly detection unit 509 detects an anomaly in the photoelectric converter 502, it notifies the main control unit 513 of the anomaly.

[0201] The integrated circuit 503 may be implemented by specially designed hardware, by a software module, or by a combination of these. It may also be implemented by an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or a combination of these.

[0202] The main control unit 513 coordinates and controls the operation of the light detection system 501, vehicle sensor 510, control unit 520, etc. Note that the vehicle 500 does not necessarily have to have the main control unit 513. In this case, the photoelectric converter 502, vehicle sensor 510, and control unit 520 send and receive control signals via a communication network. For example, the CAN standard may be applied to the transmission and reception of these control signals.

[0203] The integrated circuit 503 has the function of receiving control signals from the main control unit 513 or transmitting control signals and set values ​​to the photoelectric converter 502 via its own control unit.

[0204] The light detection system 501 is connected to the vehicle sensor 510 and can detect the vehicle's driving conditions, such as vehicle speed, yaw rate, and steering angle, as well as the external environment and the state of other vehicles and obstacles. The vehicle sensor 510 also serves as a distance information acquisition means for acquiring distance information to objects. Furthermore, the light detection system 501 is connected to the driver assistance control unit 511, which performs various driving assistance functions such as automatic steering, automatic cruising, and collision avoidance. In particular, regarding the collision judgment function, it determines whether a collision with another vehicle or obstacle has occurred and estimates a collision based on the detection results of the light detection system 501 and the vehicle sensor 510. This enables avoidance control when a collision is estimated and activation of safety devices in the event of a collision.

[0205] Furthermore, the light detection system 501 is also connected to a warning device 512 that issues a warning to the driver based on the judgment result of the collision judgment unit. For example, if the collision judgment unit determines that there is a high probability of collision, the main control unit 513 performs vehicle control to avoid a collision or mitigate damage by applying the brakes, releasing the accelerator, or suppressing engine output. The warning device 512 warns the user by sounding an alarm, displaying warning information on a display screen such as the car navigation system or instrument panel, or vibrating the seat belt or steering wheel.

[0206] In this embodiment, the light detection system 501 captures images of the area around the vehicle, for example, the front or rear. Figure 33(b) shows an example of the arrangement of the light detection system 501 when it captures images of the front of the vehicle.

[0207] As described above, the photoelectric converter 502 is positioned in front of the vehicle 500. Specifically, it is preferable for acquiring distance information between the vehicle 500 and the object being photographed and for determining the possibility of collision if the two photoelectric converters 502 are positioned symmetrically with respect to the axis of symmetry, considering the center line with respect to the vehicle 500's direction of movement or external shape (e.g., vehicle width). Furthermore, it is preferable that the photoelectric converter 502 is positioned so as not to obstruct the driver's field of view when the driver is visually observing the situation outside the vehicle 500 from the driver's seat. It is preferable that the warning device 512 is positioned so as to be easily visible to the driver.

[0208] Next, the fault detection operation of the photoelectric converter 502 in the photodetection system 501 will be explained using Figure 35. The fault detection operation of the photoelectric converter 502 can be performed according to steps S110 to S180 shown in Figure 35.

[0209] Step S110 is a step in which the photoelectric converter 502 is configured for startup. Specifically, settings for the operation of the photoelectric converter 502 are transmitted from outside the photodetection system 501 (e.g., the main control unit 513) or from inside the photodetection system 501, and the imaging operation and fault detection operation of the photoelectric converter 502 are started.

[0210] Next, in step S120, a pixel signal is acquired from the active pixels. Also, in step S130, an output value is acquired from a fault detection pixel provided for fault detection. This fault detection pixel, like the active pixels, is equipped with a photoelectric conversion element. A predetermined voltage is written to this photoelectric conversion element. The fault detection pixel outputs a signal corresponding to the voltage written to this photoelectric conversion element. Note that steps S120 and S130 may be reversed.

[0211] Next, in step S140, a determination is made between the expected output value of the fault-detection pixel and the actual output value from the fault-detection pixel. If the determination in step S140 shows that the expected output value and the actual output value match, the process proceeds to step S150, where it is determined that the imaging operation is functioning normally, and the process moves to step S160. In step S160, the pixel signals of the scanned row are transmitted to the memory 505 for temporary storage. After that, the process returns to step S120 and continues the fault detection operation. On the other hand, if the determination in step S140 shows that the expected output value and the actual output value do not match, the process proceeds to step S170. In step S170, it is determined that there is an abnormality in the imaging operation, and an alarm is sent to the main control unit 513 or the alarm device 512. The alarm device 512 displays that an abnormality has been detected on its display unit. Subsequently, in step S180, the photoelectric converter 502 is stopped, and the operation of the photodetection system 501 is terminated.

[0212] In this embodiment, an example is shown where the flowchart is looped every row, but the flowchart may be looped every multiple rows, or the fault detection operation may be performed every frame. The alarm in step S170 may be notified to an external party via a wireless network.

[0213] Furthermore, although this embodiment describes control to avoid collisions with other vehicles, it can also be applied to control that automatically follows other vehicles or control that automatically drives without deviating from the lane. Moreover, the light detection system 501 can be applied not only to vehicles such as the vehicle itself, but also to moving objects (mobile devices) such as ships, aircraft, or industrial robots. In addition, it can be applied not only to moving objects, but also to a wide range of devices that utilize object recognition, such as intelligent transportation systems (ITS).

[0214] [17th Embodiment] A photodetection system according to the 17th embodiment of the present invention will be described with reference to Figure 36. Figure 36 is a schematic diagram showing an example of the configuration of the photodetection system according to this embodiment. In this embodiment, an example of application to eyeglasses (smart glasses) will be described as a photodetection system to which the photoelectric converter 100 described in the first to 12th embodiments is applied.

[0215] Figure 36(a) shows eyeglasses 600 (smart glasses) relating to one application example. The eyeglasses 600 includes a lens 601, a photoelectric converter 602, and a control device 603.

[0216] The photoelectric converter 602 is the photoelectric converter 100 described in the first to twelfth embodiments and is provided on the lens 601. There may be one or more photoelectric converters 602. Furthermore, when using multiple photoelectric converters 602, multiple types of photoelectric converters 602 may be used in combination. The arrangement position of the photoelectric converter 602 is not limited to that shown in Figure 36(a). A display device (not shown) including a light-emitting device such as an OLED or LED may be provided on the back side of the lens 601.

[0217] The control device 603 functions as a power supply that provides power to the photoelectric converter 602 and the display device. The control device 603 also has a function to control the operation of the photoelectric converter 602 and the display device. The lens 601 is provided with an optical system for focusing light onto the photoelectric converter 602.

[0218] Figure 36(b) shows eyeglasses 610 (smart glasses) relating to another application example. The eyeglasses 610 have lenses 611 and a control device 612. The control device 612 may be equipped with a photoelectric converter (not shown) corresponding to a photoelectric converter 602 and a display device. The lenses 611 are provided with the photoelectric converter in the control device 612 and an optical system for projecting light from the display device, thereby projecting an image. The control device 612 functions as a power source that supplies power to the photoelectric converter and the display device, and also has a function to control the operation of the photoelectric converter and the display device.

[0219] The control device 612 may further include a gaze detection unit that detects the wearer's gaze. In this case, the control device 612 can be provided with an infrared light emitter, and the infrared light emitted from the infrared light emitter can be used for gaze detection. Specifically, the infrared light emitter emits infrared light towards the eyeball of the user who is gazing at the displayed image. An image capture unit having a light-receiving element detects the reflected light from the eyeball of the emitted infrared light, thereby obtaining an image of the eyeball. By having a reduction means that reduces the light from the infrared light emitter to the display unit in a planar view, the deterioration of image quality can be reduced.

[0220] The user's gaze towards a displayed image can be detected from an image of the eyeball obtained by imaging with 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 the Purkinje image obtained by the reflection of the irradiated light from the cornea can be used. More specifically, gaze detection processing based on the pupil-corneal reflection method is performed. Using the pupil-corneal reflection method, the user's gaze is detected by calculating a gaze vector representing the orientation (rotation angle) of the eyeball based on the pupil image and the Purkinje image contained in the image of the eyeball.

[0221] The display device of this embodiment may include a photoelectric converter having a light-receiving element and be configured to control the displayed image based on the user's gaze information from the photoelectric converter. Specifically, the display device determines a first field of view area that the user is fixated on and a second field of view area other than the first field of view area, based on the gaze information. The first and second field of view areas may be determined by the control device of the display device or by an external control device. If an external control device determines them, this information is transmitted to the display device via communication. 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 the resolution of the first field of view area.

[0222] Furthermore, the display area may have a first display area and a second display area different from the first display area, and may be configured to determine the area with higher priority from the first display area and the second display area based on gaze information. The first display area and the second display area may be determined by the control device of the display device or by an external control device. If the external control device makes the determination, it is communicated to the display device via communication. The resolution of the high-priority area may be controlled to be higher than the resolution of the areas other than the high-priority area. In other words, the resolution of areas with relatively lower priority may be lower.

[0223] AI may be used to determine the first field of view area and the areas with higher priority. The AI ​​may be a model configured to estimate the angle of gaze and the distance to the target object at the end of the line of sight from the image of the eye, using the image of the eye and the direction the eye was actually looking in that image as training data. The AI ​​program may be installed in the display device, the photoelectric converter, or an external device. If installed in an external device, it will be transmitted to the display device via communication.

[0224] When display control is based on visual detection, this method is preferably applicable to smart glasses that further include a photoelectric converter for capturing images of the surrounding environment. The smart glasses can display the captured external information in real time.

[0225] [Modified Embodiment] The present invention is not limited to the embodiments described above and can be modified in various ways. For example, an example in which a part of the configuration of one embodiment is added to another embodiment, or in which a part of the configuration of another embodiment is replaced, is also an embodiment of the present invention.

[0226] Furthermore, the circuit configuration of the pixel 12 is not limited to the above embodiment. For example, a switch such as a transistor may be provided between the photoelectric conversion element 22 and the quench element 32, or between the photoelectric conversion element 22 and the signal processing unit 30, to control the electrical connection state between them. Alternatively, a switch such as a transistor may be provided between the node to which voltage VH is supplied and the quench element 32, and / or between the node to which voltage VL is supplied and the photoelectric conversion element 22, to control the electrical connection state between them. In addition, multiple photoelectric conversion elements 22 may be provided for a single pixel 12.

[0227] Furthermore, in the circuit configuration of the pixel 12 in the above embodiment, the anode side of the APD is set to a fixed potential and signal charge (electrons) is extracted from the cathode side. However, it is also possible to configure the APD so that the cathode side is set to a fixed potential and signal charge (holes) is extracted from the anode side. In this case, the conductivity type of each semiconductor region described in the above embodiment may be an inverse conductivity type.

[0228] Furthermore, although the above embodiment shows a configuration in which a counter circuit is used as the processing circuit 36, a TDC (Time to Digital Converter) and memory may be used instead of the counter circuit. In this case, the generation timing of the pulse signal output from the waveform shaping circuit 34 is converted into a digital signal by the TDC. When measuring the timing of the pulse signal, the TDC is supplied with a control pulse pREF (reference signal) from the vertical scanning circuit unit 40 via the control line 14. The TDC uses the control pulse pREF as a reference and acquires the signal as a digital signal when the input timing of the signal output from each pixel 12 is set to a relative time.

[0229] It should be noted that the above embodiments are merely examples of how the present invention can be implemented, and the technical scope of the present invention should not be interpreted as being limited by them. In other words, the present invention can be implemented in various forms without departing from its technical concept or its main features.

[0230] The above-disclosed embodiment includes the following configuration. (Composition 1) A first semiconductor layer on which an avalanche photodiode is provided, A second semiconductor layer is arranged so as to overlap the first semiconductor layer in a plan view, A first insulating portion and a second insulating portion are provided so as to penetrate the second semiconductor layer, A first through-electrode that penetrates the first insulating portion and is electrically connected to the first electrode of the avalanche photodiode, It has a second through-electrode that penetrates the second insulating portion and is electrically connected to the second electrode of the avalanche photodiode, The first insulating portion and the second insulating portion are provided in the second semiconductor layer spaced apart from each other. A photoelectric conversion device characterized by the following features. (Configuration 2) The second semiconductor layer has a first surface on which an element electrically connected to the avalanche photodiode is provided, and a second surface facing the first semiconductor layer. A photoelectric conversion device according to configuration 1, characterized by the features described above. (Composition 3) The avalanche photodiode includes a plurality of avalanche photodiodes, The first through-electrode includes a plurality of first through-electrodes electrically connected to each of the plurality of avalanche photodiodes, The plurality of first through electrodes penetrate one of the first insulating portions. A photoelectric conversion device according to configuration 1 or 2, characterized by the above. (Composition 4) The avalanche photodiode includes a plurality of avalanche photodiodes, The first through electrode is electrically connected to each of the plurality of avalanche photodiodes. A photoelectric conversion device according to configuration 1 or 2, characterized by the above. (Composition 5) The device further includes a connection portion that electrically connects the plurality of first electrodes to each other. The first through electrode is electrically connected to the plurality of avalanche photodiodes via the connection portion. The photoelectric conversion device according to configuration 4, characterized by the features described above. (Composition 6) The aforementioned connection portion is formed by wiring provided on the first surface of the first semiconductor layer facing the second semiconductor layer. The photoelectric conversion device according to configuration 5, characterized by the features described herein. (Composition 7) The connection portion is composed of a semiconductor region provided in the first semiconductor layer. The photoelectric conversion device according to configuration 5, characterized by the features described herein. (Composition 8) The plurality of avalanche photodiodes each have a rectangular shape in a plan view and are arranged in a matrix. The first insulating portion is positioned so as to overlap with the corner of the rectangular shape in a plan view. The second insulating portion is positioned so as to overlap with the central part of the rectangular shape in a plan view. A photoelectric conversion device according to any one of configurations 3 to 7, characterized by the above. (Composition 9) The first insulating portion is positioned at least one of the locations that coincide with the four corners of the rectangular shape in a plan view. A photoelectric conversion device according to configuration 8, characterized by the above. (Composition 10) The first insulating portion overlaps, in a plan view, with the adjacent corners of the four avalanche photodiodes. A photoelectric conversion device according to configuration 8, characterized by the above. (Composition 11) The first through-electrode is electrically connected to two of the four avalanche photodiodes. A photoelectric conversion device according to configuration 10, characterized by the above. (Composition 12) The first through electrode is electrically connected to the four avalanche photodiodes. A photoelectric conversion device according to configuration 10, characterized by the above. (Composition 13) The second through-electrode includes a plurality of second through-electrodes electrically connected to each of the plurality of avalanche photodiodes, The second insulating portion includes a plurality of second insulating portions corresponding to the plurality of second through electrodes, The plurality of second insulating portions are provided in the second semiconductor layer spaced apart from each other. A photoelectric conversion device according to any one of configurations 3 to 12, characterized by the above. (Composition 14) The second semiconductor layer further comprises a plurality of quench elements and a plurality of waveform shaping circuits, each of which is electrically connected to the avalanche photodiode via the second through-electrode. The plurality of quench elements and the plurality of waveform shaping circuits are arranged in a plan view adjacent to the second through electrode, to which each is electrically connected. A photoelectric conversion device according to configuration 13, characterized by the features described above. (Composition 15) The plurality of second through electrodes are arranged in a matrix in a plan view, The plurality of quench elements and the plurality of waveform shaping circuits are alternately arranged in the region between the second through electrodes in the column direction and the row direction, respectively. A photoelectric conversion device according to configuration 14, characterized by the features described above. (Composition 16) The plurality of second through electrodes are arranged in a matrix in a plan view, The plurality of quench elements are arranged in the region between the second through electrodes in either the column direction or the row direction, The plurality of waveform shaping circuits are arranged in the region between the second through electrodes in the column direction and the other of the row direction. A photoelectric conversion device according to configuration 14, characterized by the features described above. (Composition 17) The optical diffusion structure is further provided between the first semiconductor layer and the second semiconductor layer. A photoelectric conversion device according to any one of configurations 1 to 16, characterized by the above. (Composition 18) The light diffusion structure is provided on the first surface of the first semiconductor layer facing the second semiconductor layer. A photoelectric conversion device according to configuration 17, characterized by the features described above. (Composition 19) The light-diffusing structure is provided in an insulating layer located between the first semiconductor layer and the second semiconductor layer. A photoelectric conversion device according to configuration 17, characterized by the features described above. (Composition 20) The optical reflective structure further comprises an insulating material provided between the first semiconductor layer and the second semiconductor layer. A photoelectric conversion device according to any one of configurations 1 to 19, characterized by the above. (Composition 21) The aforementioned light-reflecting structure is located in a region that overlaps with the second semiconductor layer in a plan view. A photoelectric conversion device according to configuration 20, characterized by the features described above. (Composition 22) The present invention further comprises a light-absorbing structure provided between the first semiconductor layer and the second semiconductor layer. A photoelectric conversion device according to any one of configurations 1 to 19, characterized by the above. (Composition 23) The light-absorbing structure is located in a region that overlaps with the second semiconductor layer in a plan view. A photoelectric conversion device according to configuration 22, characterized by the features described above. (Composition 24) The first semiconductor layer further has a scattering diffraction structure provided on a second surface opposite to the first surface facing the second semiconductor layer. A photoelectric conversion device according to any one of configurations 1 to 23, characterized by the above. (Composition 25) The first semiconductor layer further comprises a microlens array provided on the second surface side opposite to the first surface facing the second semiconductor layer, The microlens array includes two or more microlenses corresponding to one of the avalanche photodiodes. A photoelectric conversion device according to any one of configurations 1 to 24, characterized by the above. (Composition 26) The photoelectric conversion device according to any one of Configurations 1 to 25, and a signal processing device that processes a signal output from the photoelectric conversion device A photodetection system characterized by comprising the above. (Configuration 27) The signal processing device generates a distance image representing distance information to an object based on the signal. The photodetection system according to Configuration 26, characterized by the above. (Configuration 28) A moving body, The photoelectric conversion device according to any one of Configurations 1 to 25, distance information acquisition means for acquiring distance information to an object from a parallax image based on a signal output from the photoelectric conversion device, control means for controlling the moving body based on the distance information A moving body characterized by comprising the above.

Explanation of Signs

[0231] 12…Pixels 22…Photoelectric conversion element 32…Quenching element 34…Waveform shaping circuit 100…Photoelectric conversion device 110…Sensor substrate 111…Semiconductor layer 130…Circuit board 131…Semiconductor layer 132…Insulating portion 146, 167…Through electrodes

Claims

1. A first semiconductor layer on which an avalanche photodiode is provided, A second semiconductor layer is arranged so as to overlap the first semiconductor layer in a plan view, A first insulating portion and a second insulating portion are provided so as to penetrate the second semiconductor layer, A first through-electrode penetrates the first insulating portion and is electrically connected to the first electrode of the avalanche photodiode, It has a second through-electrode that penetrates the second insulating portion and is electrically connected to the second electrode of the avalanche photodiode, The first insulating portion and the second insulating portion are provided in the second semiconductor layer spaced apart from each other. A photoelectric conversion device characterized by the following features.

2. The second semiconductor layer has a first surface on which an element electrically connected to the avalanche photodiode is provided, and a second surface facing the first semiconductor layer. The photoelectric conversion device according to claim 1, characterized by the features described above.

3. The avalanche photodiode includes a plurality of avalanche photodiodes, The first through-electrode includes a plurality of first through-electrodes electrically connected to each of the plurality of avalanche photodiodes, The plurality of first through electrodes penetrate one of the first insulating portions. The photoelectric conversion device according to claim 1, characterized by the features described above.

4. The avalanche photodiode includes a plurality of avalanche photodiodes, The first through electrode is electrically connected to each of the plurality of avalanche photodiodes. The photoelectric conversion device according to claim 1, characterized by the features described above.

5. The device further includes a connection portion that electrically connects the plurality of first electrodes to each other. The first through electrode is electrically connected to the plurality of avalanche photodiodes via the connection portion. The photoelectric conversion device according to feature 4.

6. The connection portion is formed by wiring provided on the first surface of the first semiconductor layer facing the second semiconductor layer. The photoelectric conversion device according to claim 5, characterized in that it is a photoelectric device.

7. The connection portion is composed of a semiconductor region provided in the first semiconductor layer. The photoelectric conversion device according to claim 5, characterized in that it is a photoelectric device.

8. The plurality of avalanche photodiodes each have a rectangular shape in a plan view and are arranged in a matrix. The first insulating portion is positioned so as to overlap with the corner of the rectangular shape in a plan view. The second insulating portion is positioned so as to overlap with the central part of the rectangular shape in a plan view. The photoelectric conversion device according to any one of claims 3 to 7.

9. The first insulating portion is positioned at least one of the locations that coincide with the four corners of the rectangular shape in a plan view. The photoelectric conversion device according to feature 8.

10. The first insulating portion overlaps, in a plan view, with the adjacent corners of the four avalanche photodiodes. The photoelectric conversion device according to feature 8.

11. The first through electrode is electrically connected to two of the four avalanche photodiodes. The photoelectric conversion device according to claim 10, characterized in that it is a photoelectric conversion device.

12. The first through electrode is electrically connected to the four avalanche photodiodes. The photoelectric conversion device according to claim 10, characterized in that it is a photoelectric conversion device.

13. The second through-electrode includes a plurality of second through-electrodes electrically connected to each of the plurality of avalanche photodiodes, The second insulating portion includes a plurality of second insulating portions corresponding to the plurality of second through electrodes, The plurality of second insulating portions are provided in the second semiconductor layer spaced apart from each other. The photoelectric conversion device according to any one of claims 3 to 7.

14. The second semiconductor layer further comprises a plurality of quench elements and a plurality of waveform shaping circuits, each of which is electrically connected to the avalanche photodiode via the second through-electrode. The plurality of quench elements and the plurality of waveform shaping circuits are arranged in a plan view adjacent to the second through electrode, to which each is electrically connected. The photoelectric conversion device according to claim 13, characterized in that it is a photoelectric conversion device.

15. The plurality of second through electrodes are arranged in a matrix in a plan view, The plurality of quench elements and the plurality of waveform shaping circuits are alternately arranged in the region between the second through electrodes in the column direction and the row direction, respectively. The photoelectric conversion device according to claim 14.

16. The plurality of second through electrodes are arranged in a matrix in a plan view, The plurality of quench elements are arranged in the region between the second through electrodes in either the column direction or the row direction, The plurality of waveform shaping circuits are arranged in the region between the second through electrodes in the column direction and the other of the row direction. The photoelectric conversion device according to claim 14.

17. The optical diffusion structure is further provided between the first semiconductor layer and the second semiconductor layer. The photoelectric conversion device according to any one of claims 1 to 7.

18. The light diffusion structure is provided on the first surface of the first semiconductor layer facing the second semiconductor layer. The photoelectric conversion device according to claim 17, characterized in that it is a photoelectric conversion device.

19. The light-diffusing structure is provided in an insulating layer located between the first semiconductor layer and the second semiconductor layer. The photoelectric conversion device according to claim 17, characterized in that it is a photoelectric conversion device.

20. The present invention further comprises a light-reflecting structure made of an insulating material provided between the first semiconductor layer and the second semiconductor layer. The photoelectric conversion device according to any one of claims 1 to 7.

21. The aforementioned light-reflecting structure is located in a region that overlaps with the second semiconductor layer in a plan view. The photoelectric conversion device according to claim 20, characterized in that it is a photoelectric conversion device.

22. The present invention further comprises a light-absorbing structure provided between the first semiconductor layer and the second semiconductor layer. The photoelectric conversion device according to any one of claims 1 to 7.

23. The light-absorbing structure is located in a region that overlaps with the second semiconductor layer in a plan view. The photoelectric conversion device according to claim 22, characterized in that it is a photoelectric conversion device.

24. The first semiconductor layer further has a scattering diffraction structure provided on a second surface opposite to the first surface facing the second semiconductor layer. The photoelectric conversion device according to any one of claims 1 to 7.

25. The first semiconductor layer further comprises a microlens array provided on the second surface side opposite to the first surface facing the second semiconductor layer, The microlens array includes two or more microlenses corresponding to one of the avalanche photodiodes. The photoelectric conversion device according to any one of claims 1 to 7.

26. A photoelectric conversion device according to any one of claims 1 to 7, A signal processing device that processes the signal output from the aforementioned photoelectric converter and A light detection system characterized by having the following features.

27. The signal processing device generates a distance image representing distance information to the object based on the signal. The light detection system according to claim 26, characterized in that it is as described above.

28. It is a mobile object, A photoelectric conversion device according to any one of claims 1 to 7, Distance information acquisition means for acquiring distance information to an object from a parallax image based on a signal output from the aforementioned photoelectric converter, Control means for controlling the moving body based on the distance information A mobile body characterized by having the following features.

Images