Photoelectric conversion device, photodetection system and mobile object

Abstract

To provide a photoelectric conversion device that can easily optimize the characteristics of an APD in the photoelectric conversion device that acquires a value corresponding to the temperature of the APD.SOLUTION: The photoelectric conversion device includes a first substrate including an avalanche photodiode and a second substrate. The first substrate and the second substrate are laminated to each other. The photoelectric conversion device has a temperature detection means arranged on at least one of the first substrate and the second substrate and having temperature-dependent output characteristics and a temperature value generation circuit arranged outside the first substrate and converting the output of the temperature detection means into a temperature value signal, which is a signal indicating temperature information.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a photoelectric conversion device, a photodetection system, and a moving object. [Background technology]

[0002] Avalanche photodiodes (APDs) have been known for some time, utilizing avalanche multiplication to enable the detection of weak light at the single photon level. The breakdown voltage that causes avalanche multiplication depends on the temperature of the APD, and the output characteristics of the APD can change with temperature changes.

[0003] Patent Document 1 describes a SiPM device having a matrix of silicon photomultipliers (SiPMs), which are an array of APDs formed on a substrate, a bias power supply connected to the SiPM matrix, and a compensation circuit coupled to the bias power supply. In the device described in Patent Document 1, the compensation circuit adjusts the bias voltage applied to the SiPM matrix in response to temperature changes in the substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 9,978,885 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to actually detect temperature changes in the device described in Patent Document 1, it is necessary to form a circuit that generates a value corresponding to the temperature of the APD and / or its surroundings. In this case, a manufacturing process for metal-oxide semiconductor field-effect transistors (MOSFETs) must be performed on the substrate on which the APD is disposed. As a result, the device described in Patent Document 1 undergoes processes that are not actually necessary for forming the APD, which may make it difficult to optimize the APD's characteristics.

[0006] Therefore, an object of the present invention is to provide a photoelectric conversion device, a light detection system, and a mobile object that can easily optimize the characteristics of an APD in a photoelectric conversion device that generates a value corresponding to the temperature of the APD and / or its surroundings. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a photoelectric conversion device comprising a first substrate including an avalanche diode and a second substrate, the first substrate and the second substrate being stacked together, a temperature detection means disposed on at least one of the first substrate and the second substrate and having temperature-dependent output characteristics, and a temperature value generation circuit disposed outside the first substrate and converting the output of the temperature detection means into a temperature value signal that is a signal indicating temperature information. [Effects of the Invention]

[0008] According to the present invention, in a photoelectric conversion device that acquires a value corresponding to the temperature of an APD, the characteristics of the APD can be easily optimized. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram showing a schematic configuration of a photoelectric conversion device according to a first embodiment of the present invention. [Figure 2] 1 is a block diagram showing a pixel in a photoelectric conversion device according to a first embodiment of the present invention. [Figure 3] 1 is a perspective view showing a photoelectric conversion device according to a first embodiment of the present invention. [Figure 4] 1 is a cross-sectional view showing a photoelectric conversion device according to a first embodiment of the present invention. [Figure 5] 1 is a plan view showing a photoelectric conversion device according to a first embodiment of the present invention. [Figure 6] 1 is a block diagram showing a temperature detection means, a temperature value generation circuit, and a temperature compensation circuit in a photoelectric conversion device according to a first embodiment of the present invention. [Figure 7] FIG. 4 is a cross-sectional view showing a photoelectric conversion device according to a second embodiment of the present invention. [Figure 8] FIG. 4 is a plan view showing a photoelectric conversion device according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a cross-sectional view showing a photoelectric conversion device according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a plan view showing a photoelectric conversion device according to a third embodiment of the present invention. [Figure 11] FIG. 10 is a cross-sectional view showing a photoelectric conversion device according to a fourth embodiment of the present invention. [Figure 12] FIG. 10 is a plan view showing a photoelectric conversion device according to a fourth embodiment of the present invention. [Figure 13] FIG. 10 is a cross-sectional view showing a photoelectric conversion device according to a fifth embodiment of the present invention. [Figure 14] FIG. 10 is a plan view showing a photoelectric conversion device according to a fifth embodiment of the present invention. [Figure 15] FIG. 10 is a plan view showing a photoelectric conversion device according to a sixth embodiment of the present invention. [Figure 16] FIG. 12 is a plan view showing a photoelectric conversion device according to a seventh embodiment of the present invention. [Figure 17] FIG. 13 is a plan view showing a photoelectric conversion device according to an eighth embodiment of the present invention. [Figure 18] 13 shows the power supply voltage control characteristics of an avalanche photodiode by a compensation circuit according to the ninth embodiment of the present invention. [Figure 19] 13 shows the power supply voltage control characteristics of an avalanche photodiode by a compensation circuit according to the tenth embodiment of the present invention. [Figure 20] FIG. 22 is a block diagram showing an example of the configuration of a light detection system according to an eleventh embodiment of the present invention. [Figure 21] FIG. 23 is a diagram showing an example of the configuration of a light detection system and a moving body according to a twelfth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] A photoelectric conversion device according to a first embodiment of the present invention will be described with reference to FIGS.

[0011] First, the schematic configuration of a photoelectric conversion device according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the schematic configuration of a photoelectric conversion device 1010 according to this embodiment.

[0012] As shown in FIG. 1, the photoelectric conversion device 1010 includes a vertical selection circuit 103 , a horizontal selection circuit 104 , a column circuit 105 , a pixel section 106 , signal lines 107 , an output circuit 108 , and a control circuit 109 .

[0013] The pixel unit 106 has a plurality of pixels 100 arranged in a matrix. Each pixel 100 includes a photoelectric conversion element 101 and a signal processing unit 102 that processes signals output from the pixel. The photoelectric conversion element 101 photoelectrically converts incident light into an electrical signal. The signal processing unit 102 outputs the converted electrical signal to a column circuit 105.

[0014] In this specification, "light" may include electromagnetic waves of any wavelength. That is, "light" is not limited to visible light, but may also include invisible light such as infrared light, ultraviolet light, X-rays, and gamma rays.

[0015] The control circuit 109 generates control pulses for driving the vertical selection circuit 103, the horizontal selection circuit 104, and the column circuit 105, and supplies them to each of these components. In this way, the control circuit 109 controls the drive timing of each component. Note that the vertical selection circuit 103, the horizontal selection circuit 104, and the column circuit 105 may be driven by control pulses supplied from outside the photoelectric conversion device 1010.

[0016] The vertical selection circuit 103 supplies a control signal to each of the plurality of pixels 100 based on a control signal supplied from the control circuit 109. As shown in Fig. 1, the vertical selection circuit 103 supplies a control signal to each pixel 100 for each row via a control signal line provided for each row of the pixel section 106. The vertical selection circuit 103 may include logic circuits such as a shift register and an address decoder.

[0017] The signal lines 107 are provided for each column of the pixel unit 106, and transmit signals output from the pixels 100 in a row selected by the vertical selection circuit 103 as digital signals to the column circuits 105 located downstream of the pixels 100. The column circuits 105 perform predetermined processing on the signals from each pixel 100 input via the signal lines 107. Examples of predetermined processing include noise removal, amplification, and output format conversion of the input signals. To achieve these functions, the column circuits 105 may include a parallel-to-serial conversion circuit or the like.

[0018] Based on the control pulses supplied from the control circuit 109, the horizontal selection circuit 104 supplies control pulses to the column circuit 105 for sequentially outputting signals that have been subjected to predetermined processing to the output circuit 108. The output circuit 108 includes a buffer amplifier, a differential amplifier, etc., and outputs the signals output from the column circuit 105 to a recording unit or a signal processing circuit outside the photoelectric conversion device 1010.

[0019] 1, the pixels 100 in the pixel section 106 may be arranged one-dimensionally, or there may be only one pixel 100. If the pixels 100 in the pixel section 106 are divided into several blocks, a plurality of vertical selection circuits 103, horizontal selection circuits 104, and column circuits 105 may be arranged corresponding to each block. Furthermore, the horizontal selection circuits 104 and column circuits 105 may be arranged for each column.

[0020] It is not necessary for one signal processing unit 102 to be provided for each pixel 100. For example, one signal processing unit 102 may be shared by a plurality of pixels 100. In this case, the signal processing unit 102 provides a signal processing function to each pixel by sequentially processing the signals output from each photoelectric conversion element 101.

[0021] Furthermore, the signal processing unit 102 may be provided on a semiconductor substrate different from the semiconductor substrate on which the photoelectric conversion elements 101 are provided. In this case, sensitivity can be improved by increasing the ratio of the area (aperture ratio) that the photoelectric conversion elements 101 can receive light. The photoelectric conversion elements 101 and the signal processing unit 102 are electrically connected to signal lines 107 via connection wiring provided for each pixel 100. Each of the signal lines 107 may include n signal lines that transmit n-bit digital signals. Note that the vertical selection circuit 103, the horizontal selection circuit 104, and the column circuit 105, like the signal processing unit 102, may be provided on a semiconductor substrate different from the semiconductor substrate on which the photoelectric conversion elements 101 are provided.

[0022] Next, the configuration of the pixel 100 in the photoelectric conversion device 1010 according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the pixel 100 in the photoelectric conversion device 1010 according to this embodiment.

[0023] 2, the pixel 100 includes a photoelectric conversion element 101 and a signal processing unit 102. The photoelectric conversion element 101 includes a photoelectric conversion unit 201 and a control unit 202. Although both the photoelectric conversion unit 201 and the control unit 202 are provided on the same semiconductor substrate in FIG. 2, the control unit 202 may be provided on a different semiconductor substrate from that of the photoelectric conversion unit 201.

[0024] The photoelectric conversion unit 201 generates charge pairs in response to incident light through photoelectric conversion. The photoelectric conversion unit 201 uses an avalanche photodiode (APD) 13, which will be described later. A predetermined potential is supplied to the anode and cathode of the photoelectric conversion unit 201. A potential VH supplied to the cathode of the photoelectric conversion unit 201 is higher than a potential VL supplied to the anode.

[0025] Here, a potential is applied to the anode and cathode of the photoelectric conversion unit 201 to apply a reverse bias potential difference that can cause avalanche multiplication of charges generated in the photoelectric conversion unit 201. When charges are generated by incident light in a state where such a reverse bias potential difference is supplied, an avalanche current is generated due to avalanche multiplication.

[0026] When a reverse bias potential difference is applied, and the potential difference between the anode and cathode is greater than the breakdown voltage of the avalanche diode, the avalanche diode operates in Geiger mode. A photodiode that detects weak signals at the single-photon level in Geiger mode is called a single-photon avalanche diode (SPAD).

[0027] Furthermore, when the potential difference between the anode and cathode of the photoelectric conversion unit 201 is equal to or greater than the potential difference at which the charge generated in the photoelectric conversion unit 201 undergoes avalanche multiplication and is equal to or less than the breakdown voltage, the avalanche diode operates in a linear mode. An avalanche diode that detects light in a linear mode is called an avalanche photodiode (APD). In this embodiment, the photoelectric conversion unit 201 may operate as either a SPAD or an APD avalanche diode.

[0028] The control unit 202 is connected to a power supply voltage that supplies a high potential VH and the photoelectric conversion unit 201. When charges are multiplied by avalanche multiplication in the photoelectric conversion unit 201, a current obtained by the multiplied charges flows to a connection node between the photoelectric conversion unit 201 and the control unit 202. A voltage drop caused by this current reduces the potential of the cathode of the photoelectric conversion unit 201, and the photoelectric conversion unit 201 no longer forms an avalanche. This stops avalanche multiplication in the photoelectric conversion unit 201. Thereafter, the power supply potential VH is supplied to the cathode of the photoelectric conversion unit 201 via the control unit 202, and the potential supplied to the cathode of the photoelectric conversion unit 201 returns to the potential VH. In this way, the control unit 202 functions as a load circuit (quench circuit) during charge multiplication by avalanche multiplication, reducing the voltage supplied to the photoelectric conversion unit 201 to reduce avalanche multiplication (quench operation). Specific examples of circuit elements constituting the control unit 202 include a resistive element or a quench circuit. The quench circuit may be a passive quench circuit or an active quench circuit that detects an increase in avalanche current and performs feedback control to actively suppress avalanche multiplication.

[0029] The signal processing unit 102 has a waveform shaping unit 203, a counter circuit 204, and a selection circuit 206. When a signal voltage at a single photon level is input from the photoelectric conversion element 101, the waveform shaping unit 203 shapes the voltage change and outputs a pulse signal. A specific example of a circuit element constituting the waveform shaping unit 203 is an inverter circuit. While FIG. 2 shows a circuit configuration in which one inverter circuit is provided as the waveform shaping unit 203, other circuits may be used as long as they have a waveform shaping effect. For example, the waveform shaping unit 203 may be a circuit in which multiple inverter circuits are connected in series.

[0030] The counter circuit 204 counts the number of pulses in the pulse signal output from the waveform shaping unit 203. The counter circuit 204 may be, for example, an N-bit counter (N: positive integer). In this case, the counter circuit 204 can count the number of pulses up to a maximum of approximately 2 to the power of N. The count number is held in the counter circuit 204 as a detection signal. In addition, a control pulse pRES may be supplied to the counter circuit 204 from the vertical selection circuit 103 shown in FIG. 1 via a drive line 207. When the control pulse pRES is supplied to the counter circuit 204, the held count number is reset.

[0031] The selection circuit 206 switches between electrical connection and disconnection between the counter circuit 204 and the signal line 107. A control pulse pSEL is supplied to the selection circuit 206 from the vertical selection circuit 103 shown in FIG. 1 via a drive line 208. When the control pulse pSEL is supplied to the selection circuit 206, electrical connection and disconnection between the counter circuit 204 and the signal line 107 are switched depending on the level of the control pulse pSEL. The selection circuit 206 may include, for example, a transistor, a buffer circuit for outputting a signal to the outside of the pixel 100, and the like. When the counter circuit 204 and the signal line 107 are electrically connected, a digital signal indicating the count value of the detection signal held in the counter circuit 204 is transmitted to the signal line 107.

[0032] Instead of the selection circuit 206, a switch such as a transistor may be provided at a node between the control unit 202 and the photoelectric conversion unit 201, or between the photoelectric conversion element 101 and the signal processing unit 102, etc. In this case, too, a function similar to that of the selection circuit 206 can be realized by switching between connection and disconnection of the switch. Similarly, a function similar to that of the selection circuit 206 can be realized by switching between supply and non-supply of a potential to the control unit 202 or the photoelectric conversion element 101 using a switch such as a transistor.

[0033] Each pixel 100 in the pixel unit 106 can be driven by a rolling shutter operation or a global electronic shutter operation. A signal obtained from each pixel 100 can be used to generate an image based on incident light on the pixel unit 106.

[0034] The rolling shutter operation is an operation in which the count values ​​in the counter circuits 204 are reset and signals are output from the counter circuits 204 sequentially at different timings for each row. The global electronic shutter operation is an operation in which the counts in the counter circuits 204 of all rows are reset simultaneously, and then the signals held in the counter circuits 204 are output sequentially for each row.

[0035] When performing a global electronic shutter operation, in order to make the pulse counting time the same for each row, it is preferable to further add a means for switching whether or not to perform counting in the counter circuit 204. The means for switching whether or not to perform counting can be, for example, a switch such as a transistor.

[0036] Furthermore, a time-to-digital converter (hereinafter referred to as TDC) and a memory may be provided instead of the counter circuit 204. In this case, the photoelectric conversion device 1010 can acquire the timing at which the pulse is detected.

[0037] In this modification, the generation timing of the pulse signal output from the waveform shaping unit 203 is converted into a digital signal by the TDC. A control pulse pREF is supplied to the TDC from the vertical selection circuit 103 via a drive line as a reference signal used to measure the timing of the pulse signal. The TDC acquires a digital signal corresponding to the input time of the pulse from the waveform shaping unit 203, using the control pulse pREF as a time reference.

[0038] The TDC circuit may use, for example, a delay line method in which a delay circuit is formed using a delay line in which buffer circuits are connected in series, a looped TDC method in which a circuit in which delay lines are connected in a loop, etc. Other methods may also be used for the TDC circuit, but in order to ensure sufficient time resolution, it is preferable that the method be one that can achieve time resolution equal to or greater than that of the photoelectric conversion unit 201.

[0039] The digital signal acquired by the TDC is stored in one or more memories. When there are multiple memories, a signal can be selectively output to the signal line 107 from any of the memories by supplying multiple control pulses pSEL to the selection circuit 206.

[0040] Next, the layered structure of the photoelectric conversion device 1010 according to this embodiment will be described with reference to Fig. 3. Fig. 3 is a perspective view showing the photoelectric conversion device 1010 according to this embodiment.

[0041] The photoelectric conversion device 1010 is configured by stacking multiple substrates. For example, the photoelectric conversion device 1010 includes a first substrate 11 on which multiple photoelectric conversion units 201 are formed and a second substrate 12 on which multiple signal processing units 102 are formed. Each of the first substrate 11 and the second substrate 12 has a semiconductor substrate and a wiring layer. The wiring layer has an insulator such as an oxide film and a metal such as copper. The photoelectric conversion units 201 are disposed inside the semiconductor substrate of the first substrate 11. Furthermore, the counter circuit 204 and the like are disposed on the semiconductor substrate of the second substrate 12. The first substrate 11 and the second substrate 12 are bonded together at their bonding surfaces. The bonding surfaces are formed of a metal such as copper and an insulator such as an oxide film. The metal forming the bonding surfaces may form wiring connecting the photoelectric conversion units 201 disposed on the first substrate 11 to circuits disposed on the second substrate 12, such as the counter circuit 204.

[0042] Optical components such as color filters and microlenses are arranged on a first main surface, i.e., a light incident surface, of the first substrate 11. The second substrate 12 is stacked on the second main surface of the first substrate 11. A group of circuits constituting one pixel 100 is formed separately on the first substrate 11 and the second substrate 12. This makes it possible to prevent the area of ​​the photoelectric conversion device from increasing in plan view while realizing high speed or large scale digital circuits including counter circuits. The photoelectric conversion unit 201 and the signal processing unit 102 may be arranged side by side on one substrate.

[0043] Furthermore, a temperature detection means 14, which will be described later, is formed on the first substrate 11. Furthermore, a temperature value generation circuit 15, which will be described later, is formed on the second substrate 12.

[0044] Next, the configuration of the photoelectric conversion device 1010 according to this embodiment, including the APD 13, the temperature detection means 14, the temperature value generation circuit 15, and the signal processing circuit 16, will be described with reference to FIGS.

[0045] Fig. 4(a) is a cross-sectional view showing a configuration including a first substrate 11 and a second substrate 12 of a photoelectric conversion device 1010 according to this embodiment. Fig. 4(b) is a cross-sectional view showing a device structure of the first substrate 11 of the photoelectric conversion device 1010 according to this embodiment.

[0046] As shown in FIG. 4(a), a photoelectric conversion device 1010 according to this embodiment includes a first substrate 11 and a second substrate 12. The first substrate 11 and the second substrate 12 are stacked on top of each other to form a stacked structure in which circuits, circuit elements, and the like are electrically connected to each other. The semiconductor substrate of the first substrate 11 includes an APD 13 and a temperature detection unit 14. The semiconductor substrate of the second substrate 12 includes a temperature value generation circuit 15 and a signal processing circuit 16. Although wiring layers are not shown in FIGS. 4(a) and 4(b), a wiring layer is provided on the side of the first substrate facing the second substrate, and a wiring layer is provided on the side of the second substrate facing the first substrate.

[0047] The APD 13 is formed and arranged on the semiconductor substrate of the first substrate 11. The APD 13 functions as the photoelectric conversion unit 201 of the photoelectric conversion element 101 shown in FIG. 2. The cathode of the APD 13 is electrically connected to the signal processing circuit 16. Photons arriving at the APD 13 are photoelectrically converted and avalanche multiplied by the APD 13, and then subjected to signal processing by the signal processing circuit 16. The signal processing circuit 16 may include a quench resistor, a reset mechanism, and the like. The signal processing circuit 16, which processes the output signal of the APD 13 in this manner, functions as the control unit 202 shown in FIG. 2.

[0048] The temperature detection means 14 is formed and disposed on the first substrate 11. The temperature detection means 14 detects the temperature of the first substrate 11 on which the APD 13 is formed and generates an output corresponding to the temperature of the first substrate 11. The temperature detection means 14 is, for example, an element or circuit having output characteristics that depend on the temperature of the first substrate 11 on which the APD 13 is formed, and specifically, is a diode, a ring oscillator, or the like. The temperature of the first substrate 11 detected by the temperature detection means 14 is substantially the same temperature as the temperature of the APD 13 or a temperature having a predetermined relationship therewith, and indicates a value corresponding to the temperature of the APD 13. The temperature detection means 14 is electrically connected to the temperature value generation circuit 15. It is sufficient that the temperature detection means 14 is disposed on at least one of the first substrate 11 and the second substrate 12.

[0049] The temperature value generating circuit 15 is formed and disposed on the second substrate 12, which is external to the first substrate 11. The temperature value generating circuit 15 converts the output from the temperature detecting means 14 into a temperature value signal, which is a signal indicating temperature information corresponding to the temperature of the first substrate 11, and outputs the temperature value signal. For example, if the temperature detecting means 14 is a diode, the temperature value generating circuit 15 measures the voltage across the diode when a constant current is input to the diode and converts the measured voltage into a temperature value signal. In this case, the temperature value generating circuit 15 includes, for example, a resistor element or an amplifier circuit if the output is analog, or an AD conversion circuit if the output is digital. Furthermore, if the temperature detecting means 14 is a ring oscillator, for example, the temperature value generating circuit 15 counts the oscillation frequency of the ring oscillator and converts the counted oscillation frequency into a temperature value signal. In this case, the temperature value generating circuit 15 is, for example, a counter circuit. The temperature value signal is not limited to one corresponding to the temperature of the first substrate 11 detected by the temperature detection means 14, but may also be one corresponding to the temperature of the APD 13 estimated from the temperature of the first substrate 11. The temperature value generation circuit 15 can be configured to output a temperature value signal having a temperature accuracy of, for example, 5°C or less in order to achieve highly accurate temperature compensation.

[0050] 4 illustrates an example in which the temperature detection means 14 is a diode. In this case, the temperature value generation circuit 15 converts the voltage difference between the anode voltage Vt1 and the cathode voltage Vt2 when a constant current is passed through the temperature detection means 14, which is a diode, into a temperature value signal and outputs it.

[0051] Here, the power supply voltage VL of the APD 13 formed on the same first substrate 11 as the temperature detection means 14 needs to have a large voltage difference with the signal voltage VH in order to achieve avalanche multiplication. Therefore, the power supply voltage VL of the APD 13 has a different voltage range from the operating voltages (Vt1, Vt2) of the temperature detection means 14.

[0052] 4(a), the temperature detecting means 14 is formed in the first impurity region 17, and the APD 13 is formed in the second impurity region 18. As a result, the temperature detecting means 14 and the APD 13 are arranged separately in different well regions. That is, as shown in FIG. 4(b), the temperature detecting means 14 is formed as a diode including a pn junction between the first impurity region 17 and a third impurity region 19 formed in the first impurity region 17. On the other hand, the APD 13 is formed as a diode including a pn junction between the second impurity region 18 and a fourth impurity region 20 formed in the second impurity region 18. In this way, the temperature detecting means 14 and the APD 13 are well-isolated from each other.

[0053] For example, when first substrate 11 is an N-type semiconductor substrate and a power supply voltage of 1 [V] is applied, in temperature detection means 14, the anode can be P-type first impurity region 17 of 0 to 1 [V], and the cathode can be N-type third impurity region 19 of 0 [V]. In this case, in APD 13, the anode can be P-type second impurity region 18 of -several tens of V, and the cathode can be N-type fourth impurity region 20 of 0 to 1 [V].

[0054] Fig. 5(a) is a plan view showing the first substrate 11 in the photoelectric conversion device 1010 according to this embodiment. Fig. 5(b) is a plan view showing the second substrate 12 in the photoelectric conversion device 1010 according to this embodiment. Vertices A, B, C, and D of the first substrate 11 shown in Fig. 5(a) correspond to and overlap with vertices A, B, C, and D of the second substrate 12 shown in Fig. 5(b), respectively.

[0055] 5(a), a plurality of APDs 13 are arranged in an array on the first substrate 11. Only one APD 13 may be arranged on the first substrate, or a plurality of APDs 13 may be arranged in an array or in a line.

[0056] 5(b), the signal processing circuit 16 that processes the signal from the APD 13 is disposed on the second substrate 12 so as to correspond to the planar position of the APD 13, and is electrically connected to the APD 13. The signal processing circuit 16 is configured to individually process the output of each APD 13. Alternatively, the signal processing circuit 16 may be configured to process the outputs of multiple APDs 13 together as a single signal, such as in the case of SiPMs (Silicon Photomultipliers).

[0057] The temperature detection means 14 and the temperature value generation circuit 15 are arranged in close proximity to each other on the planes of the first substrate 11 and the second substrate 12, respectively, so that they can be easily electrically connected to each other.

[0058] 6 is a block diagram showing the temperature detection means 14, temperature value generation circuit 15, and compensation circuit 23 in a photoelectric conversion device 1010 according to this embodiment. The photoelectric conversion device 1010 according to this embodiment further includes a compensation circuit 23. The configurations of the temperature detection means 14, temperature value generation circuit 15, and compensation circuit 23 are not limited to those shown in FIG. 6, and various configurations can be adopted.

[0059] 6, the temperature value generation circuit 15 is electrically connected to the temperature detection means 14. The temperature value generation circuit 15 includes a current source 151, a resistor element 152, and an amplifier 153. The temperature value generation circuit 15 is electrically connected to the compensation circuit 23. The compensation circuit 23 includes an analog-to-digital converter (ADC) 231, a processor 232, a digital-to-analog converter (DAC) 233, and an amplifier 234.

[0060] The current source 151 supplies a constant current to a diode, which is the temperature detection means 14. One end and the other end of the resistance element 152 are connected to the anode and cathode of the temperature detection means 14. The amplifier 153 amplifies and outputs a voltage Vtemp applied to the resistance element 152, which corresponds to the voltage difference between the anode voltage and the cathode voltage of the temperature detection means 14. The voltage Vtemp has temperature dependency that depends on the temperature of the first substrate 11 on which the APD 13 is formed. As a result, the amplifier 153 outputs a voltage signal obtained by amplifying the voltage Vtemp as a temperature value signal that corresponds to the temperature of the first substrate 11 on which the APD 13 is formed.

[0061] The compensation circuit 23 receives a temperature value signal from the amplifier 153 of the temperature value generation circuit 15. The compensation circuit 23 is a compensation unit that compensates for changes in output characteristics of the APD 13 due to temperature changes, based on the temperature value signal from the temperature value generation circuit 15. The ADC 231 converts the temperature value signal from the amplifier 153 from an analog signal to a digital signal and outputs the digital signal. The processor 232 outputs a signal for compensating for changes in output characteristics of the APD 13 due to temperature changes, based on the temperature value signal converted into a digital signal by the ADC 231. Specifically, the processor 232 can output, for example, a voltage signal corresponding to the power supply voltage VL or VH applied to the APD 13, based on the temperature value signal. The voltage signal is converted from a digital signal to an analog signal by the DAC 233 and amplified by the amplifier 234, and then applied to the APD 13 as the power supply voltage VL or VH. In this way, the processor 232 controls the power supply voltage VL or VH applied to the APD 13 based on the temperature value signal to compensate for changes in the gain of the APD 13 due to changes in temperature, thereby compensating for changes in the output characteristics of the APD 13. Furthermore, the processor 232 can output, for example, a correction signal based on the temperature value signal to correct the output from the APD 13 due to changes in the photon detection frequency of the APD 13 depending on the temperature. In this way, the processor 232 can also correct the output from the APD 13 based on the temperature value signal to compensate for changes in the output characteristics of the APD 13.

[0062] The compensation circuit 23 may be formed on the second substrate 12 together with the temperature value generation circuit 15, or may be formed externally on another substrate different from the first substrate 11 and the second substrate 12. Furthermore, circuits included in the photoelectric conversion device 1010, such as the temperature value generation circuit 15 and the signal processing circuit 16, may be configured to also function as the compensation circuit 23. For example, the signal processing circuit 16 can function as the compensation circuit 23 by performing sensitivity correction processing, such as changing the accumulation time for accumulating charge in the APD 13 or thinning out the number of counts by the counter circuit 204, based on the temperature value signal.

[0063] The device described in Patent Document 1 requires a value corresponding to the APD temperature to adjust the bias voltage in response to temperature changes. That is, the device described in Patent Document 1 requires a temperature value generating circuit that detects the temperature of the APD itself or its surroundings and outputs a value corresponding to that temperature. If such a temperature value generating circuit is placed on the APD substrate on which the APD is formed, a manufacturing process for metal-oxide semiconductor field-effect transistors (MOSFETs) must be performed on the APD substrate, increasing the number of manufacturing steps. Furthermore, in this case, MOSFET-specific heat treatment processes, such as a gate oxide film formation process, must be performed on the APD substrate. This may result in unnecessary processes being required to form the main APD, making it difficult to optimize the APD's characteristics.

[0064] On the other hand, in this embodiment, the temperature value generating circuit 15 is disposed on a second substrate 12 that is different from and external to the first substrate 11 on which the APD 13 is disposed. Therefore, the first substrate 11 including the APD 13 does not need to undergo a process of forming a MOSFET. Therefore, compared to when the APD 13 and the temperature value generating circuit 15 are disposed on the same substrate, the photoelectric conversion device 1010 according to this embodiment can be manufactured using a manufacturing process optimized for the characteristics of the APD 13. Therefore, according to this embodiment, the characteristics of the APD 13 can be easily improved and optimized.

[0065] As described above, according to this embodiment, in the photoelectric conversion device 1010 that acquires a value corresponding to the temperature of the APD 13, the characteristics of the APD 13 can be easily optimized.

[0066] Furthermore, in this embodiment, the temperature detection means 14 is disposed on the same first substrate 11 as the APD 13, so that the temperature change of the APD 13 can be detected with higher accuracy than when the temperature detection means 14 and the APD 13 are disposed on different substrates. Therefore, according to this embodiment, the accuracy of temperature compensation for the characteristics of the APD 13 can be improved.

[0067] [Second embodiment] A photoelectric conversion device according to a second embodiment of the present invention will be described with reference to Figures 7 and 8. Note that components similar to those in the photoelectric conversion device according to the first embodiment are given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0068] The photoelectric conversion device according to this embodiment differs from the first embodiment in that the temperature detection means 14 is not included in the first substrate 11 but is included in the second substrate 12.

[0069] 7 is a cross-sectional view showing a configuration including a first substrate 11 and a second substrate 12 of a photoelectric conversion device 1010 according to this embodiment. As shown in Fig. 7, in this embodiment, unlike the first embodiment, a temperature detection means 14 is arranged on the second substrate 12, which is different from the first substrate 11 on which the APD 13 is arranged.

[0070] As described above, in this embodiment, the APD 13 and the temperature detection means 14 are disposed on separate substrates, the first substrate 11 and the second substrate 12, respectively, unlike in the first embodiment. Therefore, in this embodiment, the temperature detection means 14 may be a circuit having temperature-dependent output characteristics, such as a ring oscillator that includes a MOSFET and therefore requires its formation, or a temperature-dependent element, such as a diode, that does not require the formation of a MOSFET. When the temperature detection means 14 is a ring oscillator, for example, the temperature value generation circuit 15 monitors Vt1 as the input terminal voltage and Vt2 as the output terminal voltage, counts the oscillation frequency, and generates a temperature value signal from the count value of the oscillation frequency.

[0071] Fig. 8(a) is a plan view showing the first substrate 11 in the photoelectric conversion device 1010 according to this embodiment. Fig. 8(b) is a plan view showing the second substrate 12 in the photoelectric conversion device 1010 according to this embodiment. Vertices A, B, C, and D of the first substrate 11 shown in Fig. 8(a) correspond to and overlap with vertices A, B, C, and D of the second substrate 12 shown in Fig. 8(b), respectively.

[0072] 8(a) and 8(b), in this embodiment, unlike the first embodiment, the temperature detection means 14 is formed and arranged on the second substrate 12, not on the first substrate 11 on which the APD 13 is formed. The temperature detection means 14 arranged on the second substrate 12 is electrically connected inside the second substrate 12 to the temperature value generation circuit 15 also arranged on the second substrate 12.

[0073] In this embodiment, similar to the first embodiment, the first substrate 11 including the APD 13 does not need to undergo a process of forming a MOSFET. Therefore, in this embodiment, the photoelectric conversion device 1010 can be manufactured using a manufacturing process optimized for the characteristics of the APD 13, compared to when the APD 13 and the temperature value generating circuit 15 are arranged on the same substrate. Therefore, according to this embodiment, the characteristics of the APD 13 can be easily improved and optimized.

[0074] Furthermore, in this embodiment, the first substrate 11 on which the APD 13 is formed does not have the temperature detection means 14. Therefore, according to this embodiment, the area occupied by the APD 13 on the first substrate 11 can be increased compared to the first embodiment.

[0075] [Third embodiment] A photoelectric conversion device according to a third embodiment of the present invention will be described with reference to Figures 9 and 10. Note that components similar to those of the photoelectric conversion devices according to the first and second embodiments are given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0076] The photoelectric conversion device according to this embodiment differs from the first embodiment in that temperature detection means 14 are arranged on the second substrate 12 in addition to the first substrate 11.

[0077] 9 is a cross-sectional view showing a configuration including a first substrate 11 and a second substrate 12 of a photoelectric conversion device 1010 in this embodiment. As shown in FIG. 9, in this embodiment, unlike the first embodiment, a temperature detection means 14 is formed and arranged on the first substrate 11, and a temperature detection means 14 is also formed and arranged on the second substrate 12. The temperature detection means 14 arranged on the first substrate 11 detects the temperature of the first substrate 11. The temperature detection means 14 arranged on the second substrate 12 detects the temperature of the second substrate 12.

[0078] The temperature detecting means 14 arranged on the first substrate 11 and the temperature detecting means 14 formed on the second substrate 12 may be the same element or circuit, or may be different elements or circuits. For example, the temperature detecting means 14 arranged on the first substrate 11 and the temperature detecting means 14 formed on the second substrate 12 may both be the same diode, or the former may be a diode and the latter a ring oscillator.

[0079] The temperature detection means 14 arranged on each of the first substrate 11 and the second substrate 12 each has an independent output terminal. Therefore, in this embodiment, the temperature detection means 14 arranged on each substrate can individually detect the temperature of each of the first substrate 11 and the second substrate 12.

[0080] For example, the temperature detection means 14 disposed on each of the first substrate 11 and the second substrate 12 may both be diodes. In this case, the temperature of the first substrate 11 is detected by a change in the voltage difference between the anode voltage Vt1 and the cathode voltage Vt2 of the diode that is the temperature detection means 14 of the first substrate 11. The temperature of the second substrate 12 is detected by a change in the voltage difference between the anode voltage Vt3 and the cathode voltage Vt4 of the diode that is the temperature detection means 14 of the second substrate 12. Therefore, the voltage difference between Vt1 and Vt2 and the voltage difference between Vt3 and Vt4 may differ from each other depending on the temperature of each substrate.

[0081] The temperature value generating circuit 15 converts the output from the temperature detecting means 14 arranged on the first substrate 11 into a temperature value signal which is a signal indicating temperature information corresponding to the temperature of the first substrate 11, and outputs the temperature value signal. The temperature value generating circuit 15 also converts the output from the temperature detecting means 14 arranged on the second substrate 12 into a temperature value signal which is a signal indicating temperature information corresponding to the temperature of the second substrate 12, and outputs the temperature value signal. The temperature value signal corresponding to the temperature of the first substrate 11 and the temperature value signal corresponding to the temperature of the second substrate 12 are input to the compensation circuit 23.

[0082] Fig. 10(a) is a plan view showing the first substrate 11 in the photoelectric conversion device 1010 according to this embodiment. Fig. 10(b) is a plan view showing the second substrate 12 in the photoelectric conversion device 1010 according to this embodiment. Vertices A, B, C, and D of the first substrate 11 shown in Fig. 10(a) correspond to and overlap with vertices A, B, C, and D of the second substrate 12 shown in Fig. 10(b), respectively.

[0083] As shown in Figures 10(a) and 10(b), in this embodiment, unlike the first embodiment, the temperature detection means 14 is formed and arranged on the second substrate 12 in addition to the first substrate 11.

[0084] In this embodiment, similar to the first embodiment, the first substrate 11 including the APD 13 does not need to undergo a process of forming a MOSFET. Therefore, in this embodiment, the photoelectric conversion device 1010 can be manufactured using a manufacturing process optimized for the characteristics of the APD 13, compared to when the APD 13 and the temperature value generating circuit 15 are arranged on the same substrate. Therefore, according to this embodiment, the characteristics of the APD 13 can be easily improved and optimized.

[0085] Furthermore, in this embodiment, the temperatures of the first substrate 11 and the second substrate 12 can be simultaneously measured by the temperature detection means 14 arranged on each substrate, allowing the temperature changes of the first substrate 11 and the second substrate 12 to be compared with each other. In a configuration in which the first substrate 11 and the second substrate 12 are stacked, for example, an increase in power consumption of the signal processing circuit 16 may cause the second substrate 12 to generate more heat than the first substrate 11, resulting in the temperature change of the first substrate 11 changing in response to the temperature change of the second substrate 12. In this case, the compensation circuit 23 compensates for changes in the output characteristics of the APD 13 in response to temperature changes, based on a temperature value signal corresponding to the temperature of the second substrate 12. Therefore, this embodiment allows for rapid compensation for changes in the output characteristics of the APD 13 in response to temperature changes.

[0086] [Fourth embodiment] A photoelectric conversion device according to a fourth embodiment of the present invention will be described with reference to Figures 11 and 12. Note that components similar to those of the photoelectric conversion devices according to the first to third embodiments are given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0087] The photoelectric conversion device of this embodiment differs from the first embodiment in that it includes a first component 21 and a second component 22 which are semiconductor components different from each other.

[0088] 11 is a cross-sectional view showing a configuration of a photoelectric conversion device 1010 according to this embodiment, including a first component 21 and a second component 22. As shown in FIG. 11, the photoelectric conversion device 1010 according to this embodiment has a newly defined first component 21 and a second component 22. The first component 21 is a semiconductor chip including a first substrate 11 and a second substrate 12. The second component is a semiconductor member different from the first component 21.

[0089] Furthermore, in this embodiment, unlike the first embodiment, the temperature value generation circuit 15 is not included in the second substrate 12, but is formed and arranged in a second component 22 outside the first substrate 11. The temperature value generation circuit 15 arranged in the second component 22 is electrically connected to the temperature detection means 14 arranged on the first substrate 11.

[0090] Fig. 12(a) is a plan view showing the first substrate 11 and the second component 22 in the photoelectric conversion device 1010 according to this embodiment. Fig. 12(b) is a plan view showing the second substrate 12 in the photoelectric conversion device 1010 according to this embodiment. Vertices A, B, C, and D of the first substrate 11 shown in Fig. 12(a) correspond to and overlap with vertices A, B, C, and D of the second substrate 12 shown in Fig. 12(b), respectively.

[0091] As shown in Figures 12(a) and 12(b), in this embodiment, unlike the first embodiment, the temperature value generating circuit 15 is formed and arranged on the second component 22, not on the second substrate 12.

[0092] In this embodiment, the temperature value generating circuit 15 is disposed on the second component 22, which is external to the first substrate 11. Therefore, as in the first embodiment, the first substrate 11 including the APD 13 does not need to undergo a process for forming a MOSFET. Therefore, in this embodiment, the photoelectric conversion device 1010 can be manufactured using a manufacturing process optimized for the characteristics of the APD 13, compared to when the APD 13 and the temperature value generating circuit 15 are disposed on the same substrate. Therefore, according to this embodiment, the characteristics of the APD 13 can be easily improved and optimized.

[0093] Furthermore, in this embodiment, the temperature value generating circuit 15 is not arranged on the second substrate 12, which reduces the number of elements required on the second substrate 12. Therefore, according to this embodiment, the surplus area on the second substrate 12 can be used for other purposes.

[0094] [Fifth embodiment] A photoelectric conversion device according to a fifth embodiment of the present invention will be described with reference to Figures 13 and 14. Note that components similar to those of the photoelectric conversion devices according to the first to fourth embodiments are given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0095] The photoelectric conversion device of this embodiment differs from that of the second embodiment in that it has a first component 21 and a second component 22 which are different semiconductor chips.

[0096] 13 is a cross-sectional view showing a configuration including a first component 21 and a second component 22 of a photoelectric conversion device 1010 according to this embodiment. As shown in FIG. 13, the photoelectric conversion device 1010 according to this embodiment has a newly defined first component 21 and a second component 22. The first component 21 is a semiconductor chip including a first substrate 11 and a second substrate 12. The second component 22 is a semiconductor member different from the first component 21.

[0097] Furthermore, in this embodiment, unlike the first embodiment, the temperature value generation circuit 15 is not included in the second substrate 12, but is formed and arranged in a second component 22 that is outside the first substrate 11. The temperature value generation circuit 15 arranged in the second component 22 is electrically connected to the temperature detection means 14 arranged on the second substrate 12.

[0098] Fig. 14(a) is a plan view showing the first substrate 11 in the photoelectric conversion device 1010 according to this embodiment. Fig. 14(b) is a plan view showing the second substrate 12 and the second component 22 in the photoelectric conversion device 1010 according to this embodiment. Vertices A, B, C, and D of the first substrate 11 shown in Fig. 14(a) correspond to and overlap with vertices A, B, C, and D of the second substrate 12 shown in Fig. 14(b), respectively.

[0099] As shown in Figures 14(a) and 14(b), in this embodiment, unlike the first embodiment, the temperature value generating circuit 15 is formed and arranged on the second component 22, not on the second substrate 12.

[0100] In this embodiment, the temperature value generating circuit 15 is disposed on the second component 22 outside the first substrate 11, and therefore, similar to the second embodiment, the first substrate 11 including the APD 13 does not need to undergo a process for forming a MOSFET. Therefore, in this embodiment, the photoelectric conversion device 1010 can be manufactured using a manufacturing process optimized for the characteristics of the APD 13, compared to when the APD 13 and the temperature value generating circuit 15 are disposed on the same substrate. Therefore, according to this embodiment, the characteristics of the APD 13 can be easily improved and optimized.

[0101] Furthermore, in this embodiment, the temperature value generating circuit 15 is not arranged on the second substrate 12, which reduces the number of elements required on the second substrate 12. Therefore, according to this embodiment, the surplus area on the second substrate 12 can be used for other purposes.

[0102] [Sixth embodiment] A photoelectric conversion device according to a sixth embodiment of the present invention will be described with reference to Fig. 15. Note that components similar to those of the photoelectric conversion devices according to the first to fifth embodiments will be given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0103] The photoelectric conversion device according to this embodiment differs from the first embodiment in that it includes a plurality of temperature detection means 14 and a plurality of temperature value generation circuits 15.

[0104] Fig. 15(a) is a plan view showing the first substrate 11 in the photoelectric conversion device 1010 according to this embodiment. Fig. 15(b) is a plan view showing the second substrate 12 in the photoelectric conversion device 1010 according to this embodiment. Vertices A, B, C, and D of the first substrate 11 shown in Fig. 15(a) correspond to and overlap with vertices A, B, C, and D of the second substrate 12 shown in Fig. 15(b), respectively.

[0105] As shown in FIGS. 15(a) and 15(b), in this embodiment, unlike the first embodiment, a plurality of temperature detection means 14 and a plurality of temperature value generation circuits 15 are each arranged at a plurality of locations on a plane. That is, a plurality of temperature detection means 14 are formed and arranged on the first substrate 11. The plurality of temperature detection means 14 are distributed and arranged at different positions on the plane of the first substrate 11. A plurality of temperature value generation circuits 15 are formed and arranged on the second substrate 12 corresponding to the plurality of temperature detection means 14. Each temperature detection means 14 is electrically connected to a corresponding temperature value generation circuit 15. Note that the temperature value generation circuits 15 may be distributed and arranged at different positions on the plane of the second substrate 12, as shown in FIG. 15(b), or may be arranged adjacent to one another in a single location on the plane.

[0106] Temperature value signals are input to the compensation circuit 23 from the plurality of temperature value generating circuits 15. This allows the compensation circuit 23 to acquire a plurality of temperature value signals from the plurality of temperature detecting means 14, i.e., the temperature distribution within the first substrate 11. The compensation circuit 23 can compensate for changes in the output characteristics of the APD 13 in response to temperature changes, based on the acquired temperature distribution within the first substrate 11.

[0107] For example, the compensation circuit 23 can compensate for changes in the output characteristics of the APD 13 in response to temperature changes based on a representative value of multiple temperature value signals from multiple temperature detecting means 14, i.e., a representative value of multiple temperatures in the temperature distribution within the first substrate 11. Furthermore, the compensation circuit 23 can compensate for changes in the output characteristics of the APD 13 in response to temperature changes based on, for example, a result of calculating an average or the like for multiple temperatures indicated by multiple temperature value signals from multiple temperature detecting means 14. In this case, the compensation circuit 23 can perform temperature compensation collectively for all APDs 13 formed on the first substrate 11, or can perform temperature compensation for each region according to positional information in the temperature distribution within the substrate.

[0108] As described above, according to this embodiment, it is possible to compensate for changes in the output characteristics of the APD 13 in response to temperature changes based on the temperature distribution within the first substrate 11, thereby achieving detailed temperature compensation.

[0109] [Seventh embodiment] A photoelectric conversion device according to the seventh embodiment of the present invention will be described with reference to Fig. 16. Note that components similar to those of the photoelectric conversion devices according to the first to sixth embodiments will be given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0110] The photoelectric conversion device according to this embodiment differs from the second embodiment in that it includes a plurality of temperature detection means 14 and a plurality of temperature value generation circuits 15.

[0111] Fig. 16(a) is a plan view showing the first substrate 11 in the photoelectric conversion device 1010 according to this embodiment. Fig. 16(b) is a plan view showing the second substrate 12 in the photoelectric conversion device 1010 according to this embodiment. Vertices A, B, C, and D of the first substrate 11 shown in Fig. 16(a) correspond to and overlap with vertices A, B, C, and D of the second substrate 12 shown in Fig. 16(b), respectively.

[0112] As shown in FIGS. 16(a) and 16(b), unlike the second embodiment, in this embodiment, a plurality of temperature detecting means 14 and a plurality of temperature value generating circuits 15 are each arranged at a plurality of locations on a plane. That is, a plurality of temperature detecting means 14 are formed and arranged on the second substrate 12. The plurality of temperature detecting means 14 are distributed and arranged at different locations on the plane of the second substrate 12. A plurality of temperature value generating circuits 15 are formed and arranged on the second substrate 12 corresponding to the plurality of temperature detecting means 14. Each temperature detecting means 14 is electrically connected to a corresponding temperature value generating circuit 15. Note that, like the temperature detecting means 14, the temperature value generating circuits 15 may be distributed and arranged at different locations on the plane of the second substrate 12, as shown in FIG. 16(b), or may be arranged adjacent to one another in one location on the plane.

[0113] Temperature value signals are input to the compensation circuit 23 from the plurality of temperature value generating circuits 15. This allows the compensation circuit 23 to acquire a plurality of temperature value signals from the plurality of temperature detecting means 14, i.e., the temperature distribution within the second substrate 12. The compensation circuit 23 can compensate for changes in the output characteristics of the APD 13 in response to temperature changes, based on the acquired temperature distribution within the second substrate 12.

[0114] For example, compensation circuit 23 can compensate for changes in output characteristics corresponding to temperature changes of APD 13 based on a representative value of multiple temperature value signals from multiple temperature detecting means 14, i.e., a representative value of multiple temperatures in the temperature distribution within second substrate 12. Furthermore, compensation circuit 23 can compensate for changes in output characteristics corresponding to temperature changes of APD 13 based on, for example, a result of calculating an average or the like for multiple temperatures indicated by multiple temperature value signals from multiple temperature detecting means 14. In this case, compensation circuit 23 can perform temperature compensation collectively for APDs 13 formed on first substrate 11, or can perform temperature compensation for each region according to position information in the temperature distribution within the substrate.

[0115] As described above, according to this embodiment, the change in output characteristics in response to the temperature change of the APD 13 can be compensated for based on the temperature distribution within the second substrate 12, thereby realizing detailed temperature compensation.

[0116] [Eighth embodiment] A photoelectric conversion device according to an eighth embodiment of the present invention will be described with reference to Fig. 17. Note that components similar to those of the photoelectric conversion devices according to the first to seventh embodiments will be given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0117] The photoelectric conversion device according to this embodiment differs from the fourth embodiment in that it includes a plurality of temperature detection means 14 and a plurality of temperature value generation circuits 15.

[0118] Fig. 17(a) is a plan view showing the first substrate 11 and the second component 22 in the photoelectric conversion device 1010 according to this embodiment. Fig. 17(b) is a plan view showing the second substrate 12 in the photoelectric conversion device 1010 according to this embodiment. Vertices A, B, C, and D of the first substrate 11 shown in Fig. 17(a) correspond to and overlap with vertices A, B, C, and D of the second substrate 12 shown in Fig. 17(b), respectively.

[0119] As shown in FIGS. 17(a) and 17(b), unlike the fourth embodiment, in this embodiment, a plurality of temperature detecting means 14 and a plurality of temperature value generating circuits 15 are arranged at a plurality of locations on a plane. That is, a plurality of temperature detecting means 14 are formed and arranged on the first substrate 11. The plurality of temperature detecting means 14 are distributed and arranged at different locations on the plane of the first substrate 11. A plurality of temperature value generating circuits 15 are formed and arranged on the second component 22 in correspondence with the plurality of temperature detecting means 14. Each temperature detecting means 14 is electrically connected to a corresponding temperature value generating circuit 15. Note that the temperature value generating circuits 15 may be distributed and arranged at different locations on the plane of the second component 22 as shown in FIG. 17(a), or may be arranged adjacent to one another at a single location on the plane.

[0120] Temperature value signals are input to the compensation circuit 23 from multiple temperature value generation circuits 15. This allows the compensation circuit 23 to acquire the temperature distribution within the first substrate 11. The compensation circuit 23 can compensate for changes in the output characteristics of the APD 13 due to temperature changes, based on the acquired temperature distribution within the first substrate 11. For example, the compensation circuit 23 can compensate for changes in the output characteristics of the APD 13 due to temperature changes, based on a representative value of multiple temperatures in the temperature distribution within the first substrate 11, an average of multiple temperatures, or other calculation results. In this case, the compensation circuit 23 can perform temperature compensation collectively for all APDs 13 formed on the first substrate 11, or can perform temperature compensation for each region according to position information in the temperature distribution within the substrate.

[0121] Temperature value signals are input to the compensation circuit 23 from the plurality of temperature value generating circuits 15. This allows the compensation circuit 23 to acquire a plurality of temperature value signals from the plurality of temperature detecting means 14, i.e., the temperature distribution within the first substrate 11. The compensation circuit 23 can compensate for changes in the output characteristics of the APD 13 in response to temperature changes, based on the acquired temperature distribution within the first substrate 11.

[0122] For example, the compensation circuit 23 can compensate for changes in the output characteristics of the APD 13 in response to temperature changes based on a representative value of multiple temperature value signals from multiple temperature detecting means 14, i.e., a representative value of multiple temperatures in the temperature distribution within the first substrate 11. Furthermore, the compensation circuit 23 can compensate for changes in the output characteristics of the APD 13 in response to temperature changes based on, for example, a result of calculating an average or the like for multiple temperatures indicated by multiple temperature value signals from multiple temperature detecting means 14. In this case, the compensation circuit 23 can perform temperature compensation collectively for all APDs 13 formed on the first substrate 11, or can perform temperature compensation for each region according to positional information in the temperature distribution within the substrate.

[0123] As described above, according to this embodiment, it is possible to compensate for changes in the output characteristics of the APD 13 in response to temperature changes based on the temperature distribution within the first substrate 11, thereby achieving detailed temperature compensation.

[0124] In this embodiment, the case where the temperature detecting means 14 and the temperature value generating circuits 15 are included has been described, but the temperature detecting means 14 and the temperature value generating circuits 15 may also be configured to be different from the fifth embodiment.

[0125] [Ninth embodiment] A temperature compensation method according to the ninth embodiment of the present invention will be described with reference to Fig. 18. Fig. 18 shows the power supply voltage control characteristics of the avalanche photodiode by the compensation circuit 23 in this embodiment.

[0126] In Figure 18, the horizontal axis represents temperature T, which is calculated by temperature value generation circuit 15, and the vertical axis represents power supply voltage VL of APD 13. When temperature T indicated by temperature value generation circuit 15 changes, power supply voltage VL can be controlled by compensation circuit 23 to compensate for temperature changes in APD 13 output characteristics. First, let Ti be the reference temperature for temperature compensation, and Vi be the ideal power supply voltage for power supply voltage VL of APD 13. Here, the breakdown voltage of an APD 13 may vary from individual to individual relative to the ideal power supply voltage Vi at reference temperature Ti. Therefore, the voltage V actually applied to power supply voltage VL must take into account the breakdown voltage deviation ΔVbd from the ideal power supply voltage Vi as an offset. In other words, the value of power supply voltage VL at reference temperature Ti is controlled as Vi + ΔVbd. Here, ΔVbd, the deviation of the individual breakdown voltage from the ideal value, can be positive, negative, or even zero, depending on the individual.

[0127] Furthermore, when the temperature change with respect to the reference temperature Ti is ΔT, the compensation amount (compensation value) of the power supply voltage VL per unit temperature is α. That is, the power supply voltage VL of the APD 13 is expressed as follows: VL=α×ΔT+Vi+ΔVbd Controlled by.

[0128] By performing control in this manner, it is possible to achieve temperature compensation for the power supply voltage VL while taking into consideration the individual variation (deviation) ΔVbd of the breakdown voltage of the APD 13. In this case, the individual variation ΔVbd may be the average of the individual variations of multiple avalanche photodiodes, or it may be a value for a single avalanche photodiode.

[0129] Furthermore, when performing this power supply voltage control, the temperature T calculated by the temperature value generation circuit 15 may be a value that takes into account the individual value of the temperature detection means 14. The individual value of the temperature detection means 14 is a characteristic value for each individual, such as a voltage value, a current value, or an oscillation frequency, as output from the temperature detection means 14. For example, if the temperature detection means 14 is a diode, the individual variation in the voltage value when a constant current is passed through the diode may be taken into account and reflected in the temperature calculation process of the temperature value generation circuit 15. By taking into account the individual value of the temperature detection means 14 in this way, the temperature value signal can be transmitted to the compensation circuit 23 more accurately, which may enable accurate temperature compensation of the power supply voltage VL.

[0130] [Tenth embodiment] A temperature compensation method according to a tenth embodiment of the present invention will be described with reference to Fig. 19. The difference from the temperature compensation according to the ninth embodiment is that the temperature compensation of the power supply voltage VL differs depending on the range of the temperature T.

[0131] The range between the first temperature T1 and the second temperature T2 shown in Figure 19 is defined as the first temperature range. Furthermore, the temperature range other than the first temperature range, that is, the temperature higher than the second temperature T2, is defined as the second temperature range. Regarding the temperature change ΔT in the first temperature range, the power supply voltage compensation amount per unit temperature is defined as α1, and regarding the temperature change ΔT in the second temperature range, the power supply voltage compensation amount per unit temperature is defined as α2. In this case, α2 is smaller than α1. Furthermore, the reference temperature Ti is included in the first temperature range.

[0132] The power supply voltage VL in the first temperature range can be expressed as VL = α1 × ΔT + Vi + ΔVbd. The power supply voltage VL in the second temperature range can be expressed as VL = α2 × ΔT + V2, where V2 is the power supply voltage VL at the second temperature T2, and can be expressed as V2 = α1 × (T2 - Ti) + Vi + ΔVbd.

[0133] By reducing the amount of power supply voltage compensation per unit temperature in the second temperature range, which is higher than the first temperature range, the drive frequency of the APD 13 and the signal processing circuit 16 increases under high illuminance conditions, thereby suppressing further increases in power consumption when the temperature rises. When temperature compensation for the power supply voltage VL is performed in response to temperature changes, the bias voltage between VH and VL of the APD 13 increases with increasing temperature. This increase in bias voltage further increases power consumption and leads to a temperature rise, so positive feedback may continue to be applied under high illuminance. If power consumption or temperature continues to rise, there is a concern that device operation beyond the guaranteed range may cause device destruction. This embodiment suppresses this risk, allowing for advantageous use in terms of reliability. Furthermore, α2 may be smaller than α1 or even zero.

[0134] [Eleventh embodiment] An optical detection system according to an eleventh embodiment of the present invention will be described with reference to Fig. 20. Fig. 20 is a block diagram showing an example of the configuration of the optical detection system according to this embodiment.

[0135] In this embodiment, an example of a photodetection system using a photoelectric conversion device 1010 according to any of the first to eighth embodiments will be described with reference to Fig. 20. Components having the same functions as those in Figs. 1 to 17 will be denoted by the same reference numerals, and descriptions thereof will be omitted or simplified.

[0136] First, a distance detection system, which is an example of a light detection system, will be described with reference to Fig. 20. Note that the pixel 100 of this embodiment has a TDC 209 and a memory 210 instead of the counter circuit 204 of Fig. 2.

[0137] 20 is a block diagram of the distance detection system, which includes a light source control unit 1301, a light emitting unit 1302, an optical member 1303, a photoelectric conversion device 1010, and a distance calculation unit 1309.

[0138] The light source control unit 1301 controls the driving of the light emitting unit 1302. The light emitting unit 1302 is a light emitting device that irradiates a short pulse (train) of light in the imaging direction in response to a signal from the light source control unit 1301.

[0139] Light emitted from the light emitting unit 1302 is reflected by the subject 1304. The reflected light passes through an optical member 1303 such as a lens and is received by the photoelectric conversion unit 201 of the photoelectric conversion device 1010. The photoelectric conversion unit 201 outputs a signal based on the incident light, and the signal is input to the TDC 209 via the waveform shaping unit 203, which is an inverter circuit.

[0140] The TDC 209 acquires a signal indicating the timing of light irradiation from the light-emitting unit 1302 from the light source control unit 1301. The TDC 209 compares the signal acquired from the light source control unit 1301 with the signal input from the waveform shaping unit 203. As a result, the TDC 209 outputs a digital signal indicating the time from when the light-emitting unit 1302 emits pulsed light to when the reflected light reflected by the subject 1304 is received. The digital signal output from the TDC 209 is stored in the memory 210. This process is repeated multiple times, and the memory 210 can store multiple digital signals.

[0141] Distance calculation unit 1309 calculates the distance from photoelectric conversion device 1010 to subject 1304 based on the multiple digital signals stored in memory 210. This distance detection system can be applied to, for example, an in-vehicle distance detection device. Note that, because the processing performed by distance calculation unit 1309 is digital signal processing, it is sometimes more generally referred to as signal processing means.

[0142] [Twelfth embodiment] An imaging system and a moving object according to a twelfth embodiment of the present invention will be described with reference to Fig. 21. Fig. 21(a) and Fig. 21(b) are diagrams showing the configurations of a light detection system 1000 and a moving object according to this embodiment.

[0143] 21(a) is a block diagram showing an example of a light detection system 1000 related to an in-vehicle camera. The light detection system 1000 has a photoelectric conversion device 1010 according to the first embodiment. The light detection system 1000 has an image processing unit 1030 that performs image processing on a plurality of digital signals acquired by the photoelectric conversion device 1010. Furthermore, the light detection system 1000 has a parallax calculation unit 1040 that calculates parallax (phase difference between parallax images) from the plurality of image data acquired by the image processing unit 1030.

[0144] The light detection system 1000 also includes a distance measurement unit 1050 that calculates the distance to the object based on the calculated parallax, and a collision determination unit 1060 that determines whether or not there is a possibility of collision based on the calculated distance. Here, the parallax calculation unit 1040 and the distance measurement unit 1050 are an example of a distance information acquisition unit that acquires distance information to the object. That is, the distance information is information related to the parallax, the defocus amount, the distance to the object, etc.

[0145] The collision determination unit 1060 may determine the possibility of a collision using any of these pieces of distance information. The distance information acquisition means may be realized by dedicated hardware, a software module, or a combination of these. It may also be realized by an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like, or a combination of these.

[0146] The optical detection system 1000 is connected to a vehicle information acquisition device 1310 and can acquire vehicle information such as vehicle speed, yaw rate, steering angle, etc. The optical detection system 1000 is also connected to a control ECU 1410, which is a control device that outputs a control signal to generate a braking force on the vehicle based on the determination result of the collision determination unit 1060.

[0147] The light detection system 1000 is also connected to an alarm device 1420 that issues an alarm to the driver based on the determination result of the collision determination unit 1060. For example, if the collision determination unit 1060 determines that there is a high possibility of a collision, the control ECU 1410 performs vehicle control to avoid the collision and mitigate damage by applying the brakes, releasing the accelerator, suppressing engine output, etc. The alarm device 1420 warns the user by sounding an alarm or the like, displaying alarm information on the screen of a car navigation system or the like, vibrating the seat belt or steering wheel, etc.

[0148] In this embodiment, the light detection system 1000 captures an image of the surroundings of the vehicle, for example, the front or rear. FIG. 21(b) shows the light detection system 1000 when capturing an image of the area in front of the vehicle (imaging range 1510). The vehicle information acquisition device 1310 sends instructions to the light detection system 1000 or the photoelectric conversion device 1010 to perform a predetermined operation. This configuration can further improve the accuracy of distance measurement. The vehicle may further include a control means for controlling the vehicle, which is a moving object, based on the distance information.

[0149] Although the above example describes control to prevent collision with other vehicles, the optical detection system 1000 can also be applied to control of automatic driving by following other vehicles, control of automatic driving to prevent deviation from a lane, etc. Furthermore, the optical detection system 1000 is not limited to vehicles, but can be applied to moving bodies (moving devices) such as ships, aircraft, and industrial robots. In addition, the optical detection system 1000 can be applied not only to moving bodies, but also to a wide range of devices that use object recognition, such as intelligent transport systems (ITS).

[0150] According to this embodiment, by using the photoelectric conversion device 1010 with improved detection performance, it is possible to provide a higher performance light detection system and moving object.

[0151] [Modified embodiment] The present invention is not limited to the above-described embodiments and can be modified in various ways. For example, an example in which part of the configuration of one embodiment is added to another embodiment, or an example in which part of the configuration of another embodiment is replaced with another embodiment, is also an embodiment of the present invention.

[0152] The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0153] It should be noted that the above-described embodiments are merely examples of specific embodiments for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited by these embodiments. In other words, the present invention can be carried out in various forms without departing from its technical concept or main features. [Explanation of symbols]

[0154] 11 First substrate 12 Second board 14 Temperature detection means 15 Temperature value generation circuit 16 Signal processing circuit 17 First impurity region 18 Second impurity region 19 Third impurity region 20 Fourth impurity region 21 First Part 22 Second Part 23 Compensation circuit 1010 Photoelectric conversion device

Claims

1. a first substrate including an avalanche photodiode; a second substrate, wherein the first substrate and the second substrate are stacked; a temperature detection means disposed on at least one of the first substrate and the second substrate and having an output characteristic that depends on temperature; a temperature value generating circuit disposed outside the first substrate, for converting an output of the temperature detecting means into a temperature value signal used to compensate for changes in the output characteristics of the avalanche photodiode due to temperature changes; A photoelectric conversion device comprising:

2. The temperature value generating circuit is disposed on the second substrate.

2. The photoelectric conversion device according to claim 1.

3. a first component including the first substrate and the second substrate; a second component electrically connected to the first component and different from the first component; The temperature value generating circuit is disposed in the second component.

2. The photoelectric conversion device according to claim 1.

4. The temperature detection means is disposed on the first substrate.

4. The photoelectric conversion device according to claim 1, wherein the first and second electrodes are electrically connected to each other.

5. The temperature detection means is disposed on the second substrate.

4. The photoelectric conversion device according to claim 1, wherein the first and second electrodes are electrically connected to each other.

6. The temperature detecting means is disposed on the first substrate and the second substrate.

4. The photoelectric conversion device according to claim 1, wherein the first and second electrodes are electrically connected to each other.

7. The avalanche photodiode and the temperature detection means are well-isolated from each other.

7. The photoelectric conversion device according to claim 1, wherein the first and second electrodes are electrically connected to each other.

8. a signal processing circuit disposed on the second substrate for processing an output signal of the avalanche photodiode; 8. The photoelectric conversion device according to claim 1, wherein the first and second electrodes are electrically connected to each other.

9. 9. The photoelectric conversion device according to claim 8, wherein the signal processing circuit includes a waveform shaping section and a counter circuit.

10. A plurality of the avalanche photodiodes are arranged in a matrix, A plurality of the signal processing circuits are arranged corresponding to the plurality of avalanche photodiodes.

10. The photoelectric conversion device according to claim 9.

11. The temperature value signal has a temperature accuracy of 5°C or less.

11. The photoelectric conversion device according to claim 1.

12. The temperature detecting means is disposed at a plurality of different positions on the plane of the first substrate or the second substrate.

12. The photoelectric conversion device according to claim 1, wherein the first and second electrodes are electrically connected to each other.

13. a compensation means for compensating for a change in the output characteristic of the avalanche photodiode based on the temperature value signal; 13. The photoelectric conversion device according to claim 1, wherein the first and second electrodes are electrically connected to each other.

14. a plurality of the temperature detection means are arranged at different positions on a plane of the first substrate or the second substrate, a compensation means for compensating for a change in the output characteristic of the avalanche photodiode based on a plurality of temperature value signals output by a plurality of the temperature detection means; 12. The photoelectric conversion device according to claim 1, wherein the first and second electrodes are electrically connected to each other.

15. The compensation means compensates for changes in the output characteristics of the avalanche photodiode for each area corresponding to the positions of the plurality of temperature detection means on a plane.

15. The photoelectric conversion device according to claim 14.

16. The compensation means compensates for changes in the output characteristics of the avalanche photodiode based on a representative value of the plurality of temperature value signals.

15. The photoelectric conversion device according to claim 14.

17. The compensation means compensates for changes in the output characteristics of the avalanche photodiode based on the results of calculating the plurality of temperature value signals.

15. The photoelectric conversion device according to claim 14.

18. The compensation means compensates for changes in the output characteristics of the avalanche photodiode by controlling a power supply voltage of the avalanche photodiode.

18. The photoelectric conversion device according to claim 13,

19. The compensation means compensates for changes in the output characteristics of the avalanche photodiode by correcting the output of the avalanche photodiode.

18. The photoelectric conversion device according to claim 13,

20. the temperature detection means is a diode or a ring oscillator, The temperature value generating circuit is a counter circuit, a resistor element, an amplifier circuit, or an AD conversion circuit.

20. The photoelectric conversion device according to claim 1, wherein the first and second electrodes are electrically connected to each other.

21. The temperature value generating circuit generates a temperature value signal corrected in accordance with the individual value of the temperature detecting means.

18. The photoelectric conversion device according to claim 13,

22. The individual values ​​of the temperature detection means are characteristic values ​​of each individual, such as a voltage value, a current value, or an oscillation frequency, as an output of the temperature detection means.

22. The photoelectric conversion device according to claim 21.

23. The compensation means compensates for changes in the output characteristics of the avalanche photodiode by reflecting the individual values ​​of the avalanche photodiode.

18. The photoelectric conversion device according to claim 13,

24. The individual value of the avalanche photodiode is the breakdown voltage value of the avalanche photodiode.

24. The photoelectric conversion device according to claim 23.

25. The compensation means corrects and controls the power supply voltage of the avalanche photodiode in accordance with the individual value of the breakdown voltage of the avalanche photodiode.

19. The photoelectric conversion device according to claim 18.

26. Let V be the power supply voltage value of the avalanche photodiode, ΔT be the change in the temperature value represented by the temperature value signal, α be the compensation value per unit temperature of the power supply voltage of the avalanche photodiode, Vi be the ideal power supply voltage value at a reference temperature, and ΔVbd be the deviation of the individual value of the breakdown voltage from the ideal value. V=α1×ΔT+Vi+ΔVbd 26. The photoelectric conversion device according to claim 25, wherein the power supply voltage of the avalanche photodiode is controlled by the compensation means based on an equation expressed as follows:

27. The compensation means is configured to set a compensation value per unit temperature of the temperature value signal in a first temperature range different from a compensation value per unit temperature of the temperature value signal in a temperature range other than the first temperature range.

18. The photoelectric conversion device according to claim 13,

28. The compensation value in the second temperature range, which is higher than the first temperature range, is smaller than the compensation value in the first temperature range.

28. The photoelectric conversion device according to claim 27.

29. No compensation is performed in a second temperature range that is higher than the first temperature range.

28. The photoelectric conversion device according to claim 27.

30. A first substrate including an avalanche photodiode; a second substrate, wherein the first substrate and the second substrate are stacked; a temperature detection means disposed on at least one of the first substrate and the second substrate and having an output characteristic that depends on temperature; a temperature value generating circuit disposed outside the first substrate and configured to convert an output of the temperature detecting means into a temperature value signal that indicates temperature information; a compensation circuit that compensates for changes in the output characteristics of the avalanche photodiode based on the temperature value signal; A photoelectric conversion device comprising:

31. The photoelectric conversion device according to any one of claims 1 to 30, a signal processing unit that processes a signal output from the photoelectric conversion device; An optical detection system comprising:

32. A mobile object, The photoelectric conversion device according to any one of claims 1 to 30, a distance information acquisition means for acquiring distance information to an object from a parallax image based on a signal from the photoelectric conversion device; a control means for controlling the moving object based on the distance information; A moving object characterized by having:

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