Photoelectric conversion device, apparatus, and mobile

Abstract

To provide a photoelectric conversion device having improved sensitivity to incident light while reducing influences on performance.SOLUTION: A photoelectric conversion device comprises a plurality of pixels each including an avalanche photodiode. The plurality of pixels includes a first pixel and a second pixel for performing photoelectric conversion on incident light including light of a shorter wavelength than a wavelength of incident light on which the first pixel performs photoelectric conversion. A diffraction region where incident light is diffracted is provided in the first pixel and not provided in the second pixel.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to a photoelectric conversion device, an apparatus, and a mobile object. [Background technology]

[0002] There is known a photoelectric conversion device that can detect weak light at the single photon level by using avalanche multiplication. Patent Document 1 discloses a photoelectric conversion device in which a sensor chip on which a plurality of pixels are arranged and a circuit chip on which a circuit for performing signal processing is formed are stacked and electrically connected. Avalanche photodiodes in which electric charges undergo avalanche multiplication are used for the pixels in the sensor chip of this photoelectric conversion device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2017 / 0186798 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to improve the sensitivity to incident light, a diffraction region may be provided in the semiconductor layer of a pixel using an avalanche photodiode, which increases the optical path length of the incident light in the semiconductor layer, thereby improving the sensitivity of the pixel.

[0005] However, further investigation revealed that visible light of a certain color, which has a shorter wavelength than infrared light, has a shorter penetration depth into the silicon that makes up the semiconductor layer, and therefore the effect of improving sensitivity due to the diffraction region is small in pixels that convert this visible light into an electrical signal.

[0006] Furthermore, when a diffractive region is provided in the semiconductor layer, the number of interfaces between the semiconductor layer and other layers increases, which may increase dark current and affect the performance of the photoelectric conversion device. [Means for solving the problem]

[0007] One aspect of the present disclosure is a photoelectric conversion device having a plurality of pixels each including an avalanche photodiode, the plurality of pixels including a first pixel and a second pixel that performs photoelectric conversion on incident light including light having a wavelength shorter than the wavelength of the incident light that is photoelectrically converted by the first pixel, and a diffraction region that diffracts the incident light is provided in the first pixel but not in the second pixel. Effect of the Invention

[0008] According to at least one embodiment of the present disclosure, it is possible to provide a photoelectric conversion device with improved sensitivity to incident light while reducing the impact on performance. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a photoelectric conversion device according to an embodiment. [Diagram 2] 2 is a schematic diagram of a pixel substrate of a photoelectric conversion device according to an embodiment. FIG. [Diagram 3] 2 is a schematic diagram of a circuit board of a photoelectric conversion device according to an embodiment. FIG. [Figure 4] 2 is a configuration example of a pixel circuit of a photoelectric conversion device according to an embodiment. [Diagram 5] 3 is a schematic diagram showing driving of a pixel circuit of a photoelectric conversion device according to an embodiment. FIG. [Figure 6] FIG. 2 is a schematic diagram illustrating an example of a pixel according to the first embodiment. [Figure 7] FIG. 2 is a schematic diagram illustrating an example of a pixel according to the first embodiment. [Figure 8] FIG. 11 is a schematic diagram illustrating an example of a pixel according to a second embodiment. [Figure 9] FIG. 13 is a schematic diagram illustrating an example of a pixel according to a third embodiment. [Figure 10] FIG. 13 is a schematic diagram illustrating an example of a pixel according to a fourth embodiment. [Figure 11] FIG. 13 is a schematic diagram illustrating an example of a pixel according to the fifth embodiment. [Figure 12] FIG. 13 is a schematic diagram illustrating an example of a pixel according to the sixth embodiment. [Figure 13] FIG. 13 is a schematic diagram illustrating an example of a pixel according to the seventh embodiment. [Figure 14] FIG. 23 is a schematic diagram illustrating an example of a pixel according to the eighth embodiment. [Figure 15] FIG. 13 is a schematic diagram illustrating an example of a pixel according to the ninth embodiment. [Figure 16] FIG. 23 is a schematic diagram showing an example of an apparatus according to the tenth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The embodiments described below are intended to embody the technical ideas of the present disclosure, and are not intended to limit the present disclosure. The sizes and positional relationships of the components shown in each drawing may be exaggerated to clarify the description. In the following description, the same components may be designated by the same reference numerals, and the description may be omitted.

[0011] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper", "lower", "right", "left" and other terms including these terms) will be used as necessary. The use of these terms is for the purpose of facilitating understanding of the embodiment with reference to the drawings, and the technical scope of the present disclosure is not limited by the meaning of these terms.

[0012] In this specification, the plan view refers to a view from a direction perpendicular to the light incident surface of the semiconductor layer. Also, the cross-sectional view refers to a view of a cross section perpendicular to the light incident surface of the semiconductor layer. Note that, when the light incident surface of the semiconductor layer is a rough surface when viewed microscopically, the plan view is defined based on the light incident surface of the semiconductor layer when viewed macroscopically.

[0013] The semiconductor layer has a first surface and a second surface, which is the surface opposite to the first surface and on which light is incident. In this specification, the depth direction is the direction from the first surface to the second surface of the semiconductor layer on which the avalanche photodiode (APD) is arranged. Hereinafter, the "first surface" may be referred to as the "front surface" and the "second surface" may be referred to as the "rear surface." The "depth" of a point or a region in the semiconductor layer means the distance from the first surface (front surface) of the point or region. When there is a point (or region) Z1 whose distance (depth) from the first surface is d1 and a point (or region) Z2 whose distance (depth) from the first surface is d2, and d1>d2, it may be expressed as "Z1 is deeper than Z2" or "Z2 is shallower than Z1." Also, when there is a point (or region) Z3 whose distance (depth) from the first surface is d3, and d1>d3>d2 holds, it can be expressed as "Z3 is at a depth between Z1 and Z2" or "Z3 is between Z1 and Z2 in the depth direction."

[0014] In the following description, the anode of the APD is set to a fixed potential, and a signal is taken out from the cathode side. Therefore, the first conductive type semiconductor region having charges of the same polarity as the signal charge as the majority carrier is an N-type semiconductor region, and the second conductive type semiconductor region having charges of a different polarity from the signal charge as the majority carrier is a P-type semiconductor region. Note that the present disclosure also applies when the cathode of the APD is set to a fixed potential, and a signal is taken out from the anode side. In this case, the first conductive type semiconductor region having charges of the same polarity as the signal charge as the majority carrier is a P-type semiconductor region, and the second conductive type semiconductor region having charges of a different polarity from the signal charge as the majority carrier is an N-type semiconductor region. In the following, a case where one node of the APD is set to a fixed potential will be described, but the potentials of both nodes may fluctuate.

[0015] In this specification, when the term "impurity concentration" is used simply, it means the net impurity concentration minus the amount compensated by the impurity of the opposite conductivity type. In other words, "impurity concentration" refers to the NET doping concentration. A region where the P-type doped impurity concentration is higher than the N-type doped impurity concentration is a P-type semiconductor region. Conversely, a region where the N-type doped impurity concentration is higher than the P-type doped impurity concentration is an N-type semiconductor region.

[0016] In the following embodiments, the connection between elements of a circuit may be described. In this case, even if another element is interposed between the elements of interest, the elements of interest are treated as being connected to each other unless otherwise specified. For example, assume that element A is connected to one node of a capacitive element C having multiple nodes, and element B is connected to the other node. Even in such a case, element A and element B are treated as being connected to each other unless otherwise specified.

[0017] Metallic members such as wiring and pads described in this specification may be composed of a single metal element or may be a mixture (alloy). For example, wiring described as copper wiring may be composed of a single copper element or may be composed mainly of copper and further contain other components. Also, for example, pads connected to external terminals may be composed of a single aluminum element or may be composed mainly of aluminum and further contain other components. The copper wiring and aluminum pads shown here are examples and can be changed to various metals.

[0018] Moreover, the wiring and pads shown here are one example of metal members used in a photoelectric conversion device, and the present invention can also be applied to other metal members.

[0019] In the following embodiments, an image pickup device will be mainly described as an example of a photoelectric conversion device. However, each embodiment is not limited to an image pickup device, and can be applied to other examples of photoelectric conversion devices. For example, a distance measuring device (a device for measuring distance using focus detection or TOF (Time Of Flight)) or a photometric device (a device for measuring the amount of incident light) may be used.

[0020] A configuration common to each embodiment of a photoelectric conversion device and a driving method thereof according to the present disclosure will be described with reference to FIGS. 1 to 5. FIG.

[0021] FIG. 1 is a diagram showing a configuration of a photoelectric conversion device 100 according to an embodiment of the present disclosure. In the following, a case where the photoelectric conversion device 100 is a stacked type photoelectric conversion device will be described as an example. That is, a photoelectric conversion device configured by stacking and electrically connecting two substrates, a sensor substrate 11 and a circuit substrate 21, will be described as an example. However, the photoelectric conversion device is not limited to this. For example, the photoelectric conversion device may be a photoelectric conversion device in which the configuration included in the sensor substrate 11 and the configuration included in the circuit substrate are arranged on a common semiconductor layer, as described below. In the following, a photoelectric conversion device in which the configuration included in the sensor substrate 11 and the configuration included in the circuit substrate are arranged on a common semiconductor layer is also referred to as a non-stacked photoelectric conversion device.

[0022] The sensor substrate 11 has a first semiconductor layer having a photoelectric conversion element 102 described later, and a first wiring structure. The circuit substrate 21 has a second semiconductor layer having circuits such as a signal processing circuit 103 described later, and a second wiring structure. The photoelectric conversion device 100 is configured by laminating the second semiconductor layer, the second wiring structure, the first wiring structure, and the first semiconductor layer in this order.

[0023] 1 illustrates a back-illuminated photoelectric conversion device in which light is incident from the first surface side of the first semiconductor layer of the sensor substrate 11, and a circuit substrate 21 is disposed on the second surface side of the first semiconductor layer, which is the surface opposite to the first surface. In the case of a non-stacked photoelectric conversion device, the surface on which the transistors of the signal processing circuit are disposed is referred to as the second surface.

[0024] In the case of a back-illuminated photoelectric conversion device, the first surface of the semiconductor layer opposite to the second surface serves as the light incident surface, while in the case of a front-illuminated photoelectric conversion device, the second surface of the semiconductor layer serves as the light incident surface.

[0025] In the following, the sensor substrate 11 and the circuit substrate 21 will be described as diced chips, but are not limited to chips. For example, each substrate may be a wafer. Also, each substrate may be stacked in a wafer state and then diced, or each chip may be stacked and bonded after being chipped.

[0026] A pixel region 12 is disposed on the sensor substrate 11, and a circuit region 22 that processes signals detected in the pixel region 12 is disposed on the circuit substrate 21.

[0027] 2 is a layout diagram of the sensor chip 11. Pixels 101, each having a photoelectric conversion unit 102 including an avalanche photodiode (hereinafter, APD), are arranged two-dimensionally to form a pixel region 12.

[0028] The pixel 101 is typically a pixel for forming an image, but when used for TOF (Time of Flight), it does not necessarily have to form an image. That is, the pixel 101 may be a pixel for measuring the time when light arrives and the amount of light.

[0029] 3 is a configuration diagram of the circuit chip 21. It has a signal processing unit 103 that processes the charges photoelectrically converted by the photoelectric conversion unit 102 in FIG. 2, a readout circuit 112, a control pulse generation unit 115, a horizontal scanning circuit unit 111, a signal line 113, and a vertical scanning circuit unit 110.

[0030] The photoelectric conversion unit 102 in FIG. 2 and the signal processing unit 103 in FIG. 3 are electrically connected via connection wiring provided for each pixel.

[0031] The vertical scanning circuit section 110 receives a control pulse supplied from a control pulse generating section 115 and supplies the control pulse to each pixel. The vertical scanning circuit section 110 uses logic circuits such as a shift register and an address decoder.

[0032] The control pulse generating unit 115 has a signal generating unit 215 that generates a control signal P_CLK for a switch, which will be described later. The signal generating unit 215 generates a pulse signal for controlling the switch, as will be described later. For example, as shown in FIG. 4(a), the signal generating unit 215 may generate a control signal P_CLK in common for a plurality of pixels in the pixel region, or as shown in FIG. 4(b), the control signal P_CLK may be generated for each pixel. When the pulse signal P_CLK is generated in common, at least one of the period, the number of pulses, and the pulse width of the signal P_EXP pulse signal for controlling the exposure period is generated in common in correspondence with the exposure period. When the control signal P_CLK is controlled for each pixel, a signal can be generated using both the input signal P_CLK_IN output from the control pulse generating unit 115 and the signal P_EXP for controlling the exposure period. The control pulse generating unit 115 preferably has, for example, a frequency dividing circuit. This allows simple control and reduces an increase in the number of elements.

[0033] The signal output from the photoelectric conversion unit 102 of each pixel is processed by a signal processing unit 103. The signal processing unit 103 is provided with a counter, a memory, etc., and digital values ​​are held in the memory.

[0034] The horizontal scanning circuit unit 111 inputs a control pulse for sequentially selecting each column to the signal processing unit 103 in order to read out the signal from the memory of each pixel in which the digital signal is held.

[0035] A signal is output to the signal line 113 from the signal processing unit 103 of the pixel selected by the vertical scanning circuit unit 110 for the selected column.

[0036] The signal output to the signal line 113 is output via an output circuit 114 to a recording unit or a signal processing unit outside the photoelectric conversion device 100 .

[0037] 2, the pixels 101 may be arranged one-dimensionally in the pixel region 12. The function of the signal processing unit 103 does not necessarily need to be provided for each pixel 101, and for example, one signal processing unit 103 may be shared by a plurality of pixels 101 to perform signal processing sequentially.

[0038] Fig. 4 is an example of a block diagram including the equivalent circuits of Fig. 2 and Fig. 3. In Fig. 2, a photoelectric conversion unit 102 having an APD 201 is provided on a sensor chip 11, and other members are provided on a circuit chip 21.

[0039] The APD 201 generates charge pairs according to the incident light by photoelectric conversion. A voltage VL (first voltage) is supplied to the anode of the APD 201. A voltage VH (second voltage) higher than the voltage VL supplied to the anode is supplied to the cathode of the APD 201. A reverse bias voltage that causes the APD 201 to perform avalanche multiplication is supplied to the anode and cathode. With such a voltage supplied, the charges generated by the incident light undergo avalanche multiplication, generating an avalanche current.

[0040] When a reverse bias voltage is supplied, there are two modes: Geiger mode, in which the potential difference between the anode and cathode is greater than the breakdown voltage, and linear mode, in which the potential difference between the anode and cathode is close to or less than the breakdown voltage. An APD operated in Geiger mode is called a SPAD. For example, the voltage VL (first voltage) is -30V, and the voltage VH (second voltage) is 1V. The APD201 may be operated in either linear mode or Geiger mode. The potential difference of a SPAD is greater than that of a linear mode APD, and the effect of withstanding voltage is more pronounced.

[0041] The switch 202 is connected to a control line to which a drive voltage VH is supplied and to the APD 201. The switch 202 is connected to one of the anode and cathode nodes of the APD. The switch 202 switches the potential difference between the anode and cathode of the APD between a first potential difference that causes avalanche multiplication and a second potential difference that does not cause avalanche multiplication. Hereinafter, switching from the second potential difference to the first potential difference is also referred to as turning on the switch 202, and switching from the first potential difference to the second potential difference is also referred to as turning off the switch 202. The switch 202 functions as a quenching element. The switch 202 functions as a load circuit (quenching circuit) during signal multiplication by avalanche multiplication, and has a function of suppressing avalanche multiplication by suppressing the voltage supplied to the APD 201 (quenching operation). The switch 202 also has a function of returning the voltage supplied to the APD 201 to the drive voltage VH by passing a current equivalent to the voltage drop caused by the quench operation (recharge operation). In other words, the switch 202 functions as a control circuit for controlling the occurrence of avalanche multiplication in the APD 201.

[0042] The switch 202 can be configured, for example, by a MOS transistor. A control signal P_CLK for the switch 202, which is supplied from the signal generating unit 215, is applied to a gate electrode of the MOS transistor that configures the switch 202. In this embodiment, the on / off of the switch 202 is controlled by controlling the voltage applied to the gate electrode of the switch 202.

[0043] The signal processing section 103 has a waveform shaping section 210, a counter circuit 211, and a selection circuit 212. In this specification, it is sufficient that the signal processing section 103 has at least one of the waveform shaping section 210, the counter circuit 211, and the selection circuit 212.

[0044] The waveform shaping unit 210 shapes the potential change of the cathode of the APD 201 obtained when a photon is detected, and outputs a pulse signal. The node on the input side of the waveform shaping unit 210 is nodeA, and the node on the output side is nodeB. The waveform shaping unit 210 changes the output potential from the node nodeB depending on whether the input potential to the node nodeA is equal to or higher than a predetermined value or lower. For example, in FIG. 5, when the input potential to the node nodeA becomes a high potential equal to or higher than the judgment threshold, the output potential from the node nodeB becomes a low level. When the input potential to the node nodeA becomes a potential lower than the judgment threshold, the output potential from the node nodeB becomes a high level. For example, an inverter circuit is used as the waveform shaping unit 210. In FIG. 4, an example in which one inverter is used as the waveform shaping unit 210 is shown, but a circuit in which multiple inverters are connected in series may be used, or other circuits having a waveform shaping effect may be used.

[0045] It is possible to perform a quench operation and a recharge operation using the switch 202 according to the avalanche multiplication in the APD 201, but depending on the timing of photon detection, the charge generated in the APD may not be determined as an output signal. For example, assume that avalanche multiplication occurs in the APD, the node A becomes low level, and a recharge operation is performed. In general, the decision threshold of the waveform shaping unit 210 is set to a potential higher than the potential difference at which avalanche multiplication occurs in the APD. When a photon is incident on the APD when the potential of the node A is lower than the decision threshold due to the recharge operation and the potential is such that avalanche multiplication is possible in the APD, avalanche multiplication occurs in the APD and the voltage of the node A drops. In other words, since the potential of the node A drops at a voltage lower than the decision threshold, no potential change occurs across the decision threshold, and the output potential from the node B does not change. Therefore, even though avalanche multiplication occurs, the photon detection is not determined as a signal. Particularly under high illuminance, photons enter the APD continuously in a short period of time, making it difficult for the incident light to be detected as a signal. This can lead to a discrepancy between the actual number of incident photons and the output signal, even under high illuminance.

[0046] In contrast, by applying a control signal P_CLK to the switch 202 to switch the switch 202 between an on state and an off state, it is possible to determine a signal even when photons enter the APD continuously in a short period of time. In FIG. 5, an example is described in which the control signal P_CLK is a pulse signal with a repetitive cycle. In other words, in FIG. 5, a form is described in which the switch 202 is switched on and off at a predetermined clock frequency. However, the effect of suppressing an increase in power consumption of the photoelectric conversion device can be obtained even if the pulse signal is not a signal with a repetitive cycle.

[0047] The counter circuit 211 counts the pulse signal output from the waveform shaping unit 210 and holds the count value. When a control pulse pRES is supplied via a drive line 213, the signal held in the counter circuit 211 is reset.

[0048] A control pulse pSEL is supplied to the selection circuit 212 from the vertical scanning circuit unit 110 in Fig. 1 via a drive line 214 (not shown in Fig. 3) in Fig. 4, and switches between electrical connection and non-connection between the counter circuit 211 and the signal line 113. The selection circuit 212 includes, for example, a buffer circuit for outputting a signal.

[0049] The electrical connection may be switched by disposing a switch such as a transistor between the switch 202 and the APD 201 or between the photoelectric conversion unit 102 and the signal processing unit 103. Similarly, the supply of the voltage VH or the voltage VL to the photoelectric conversion unit 102 may be electrically switched using a switch such as a transistor.

[0050] In this embodiment, a configuration using the counter circuit 211 has been shown. However, instead of the counter circuit 211, the photoelectric conversion device 100 may be configured to acquire the pulse detection timing using a time-to-digital converter (hereinafter, referred to as TDC) or a memory. In this case, the generation timing of the pulse signal output from the waveform shaping unit 210 is converted into a digital signal by the TDC. In order to measure the timing of the pulse signal, a control pulse pREF (reference signal) is supplied to the TDC from the vertical scanning circuit unit 110 in FIG. 1 via a drive line. The TDC acquires, as a digital signal, a value obtained by converting the input timing of the signal output from each pixel into a relative time based on the control pulse pREF.

[0051] FIG. 5 is a diagram showing a schematic diagram of the relationship between the control signal P_CLK of the switch, the potential of the node nodeA, the potential of the node nodeB, and the output signal. In this embodiment, when the control signal P_CLK is at a high level, the drive voltage VH is not easily supplied to the APD, and when the control signal P_CLK is at a low level, the drive voltage VH is supplied to the APD. The high level of the control signal P_CLK is, for example, 1V, and the low level of the control signal P_CLK is, for example, 0V. When the control signal P_CLK is at a high level, the switch is turned off, and when the control signal P_CLK is at a low level, the switch is turned on. The resistance value of the switch when the control signal P_CLK is at a high level is higher than the resistance value of the switch when the control signal P_CLK is at a low level. When the control signal P_CLK is at a high level, even if avalanche multiplication occurs in the APD, a recharge operation is not easily performed, so the potential supplied to the APD is a potential equal to or lower than the breakdown voltage of the APD. Therefore, the avalanche multiplication operation in the APD stops.

[0052] As shown in Fig. 5(a), it is preferable to configure the switch 202 with one transistor, and to perform the quenching operation and the recharge operation with one transistor. This makes it possible to reduce the number of circuits compared to the case where the quenching operation and the recharge operation are performed with different circuit elements. In particular, when each pixel has a counter circuit and the SPAD signal is read out for each pixel, it is preferable to reduce the circuit area used for the switch in order to place the counter circuit, and the effect of configuring the switch 202 with one transistor becomes significant.

[0053] At time t1, the control signal P_CLK changes from high level to low level, the switch is turned on, and the recharge operation of the APD is started. This causes the potential of the cathode of the APD to transition to high level. Then, the potential difference between the potentials applied to the anode and cathode of the APD becomes a state in which avalanche multiplication is possible. The potential of the cathode is the same as that of the node nodeA. Therefore, when the potential of the cathode transitions from low level to high level, the potential of the node nodeA becomes equal to or higher than the judgment threshold value at time t2. At this time, the pulse signal output from the node nodeB is inverted and goes from high level to low level. After that, the potential difference of the drive voltage VH-drive voltage VL is applied to the APD 201. The control signal P_CLK becomes high level, and the switch is turned off.

[0054] Next, at time t3, when a photon is incident on the APD 201, avalanche multiplication occurs in the APD 201, and the voltage of the cathode drops. That is, the voltage of the node nodeA drops. When the amount of voltage drop becomes larger and the voltage difference applied to the APD 201 becomes smaller, the avalanche multiplication of the APD 201 stops as at time t2, and the voltage level of the node nodeA does not drop by more than a certain value. When the voltage of the node nodeA becomes lower than the decision threshold while the voltage of the node nodeA is dropping, the voltage of the node nodeB goes from low level to high level. That is, the part of the output waveform at the node nodeA that exceeds the decision threshold is waveform-shaped by the waveform shaping unit 210 and output as a signal at the nodeB. Then, it is counted by the counter circuit, and the count value of the counter signal output from the counter circuit increases by 1 LSB.

[0055] Between time t3 and time t4, photons are incident on the APD. However, since the switch is off and the voltage applied to the APD 201 does not have a potential difference that allows avalanche multiplication, the voltage level of the node A does not exceed the decision threshold.

[0056] At time t4, the control signal P_CLK changes from high to low, and the switch is turned on. As a result, a current flows to node A to compensate for the voltage drop from the drive voltage VH, and the voltage of node A transitions to its original voltage level. At this time, the voltage of node A becomes equal to or higher than the decision threshold at time t5, so the pulse signal of node B is inverted and goes from high to low.

[0057] At time t6, node A is stabilized to the original voltage level, and the control signal P_CLK goes from low to high. Therefore, the switch is turned off. After this, the potentials of the nodes and signal lines change in response to the control signal P_CLK and the incidence of photons, as described from time t1 to time t6.

[0058] The photoelectric conversion devices of the respective embodiments will be described below.

[0059] (First embodiment) Fig. 6 is a plan view showing an example of a pixel according to the first embodiment. Fig. 7 is a view showing a part of a cross section taken along line AA' in Fig. 6. Fig. 7 shows cross sections of two pixels 101.

[0060] The semiconductor layer 310 is made of, for example, silicon. A pinning film 321, a planarization layer 322, and a filter layer 323 are arranged in this order on a first surface (light incident surface) of the semiconductor layer 310, and microlenses 324 corresponding to each pixel are further provided above them. That is, the photoelectric conversion device according to the first embodiment has a so-called back-illuminated structure in which light is incident on the semiconductor layer 310 from the first surface side.

[0061] The pinning film 321 is made of a dielectric material having a negative fixed charge, and is disposed over the entire first surface of the semiconductor layer 310. The material of the pinning film 321 is selected from, for example, hafnium oxide, aluminum oxide, zirconium oxide, titanium oxide, tantalum oxide, and ruthenium oxide, and among these, aluminum oxide or hafnium oxide is preferable. The pinning film 321 may be configured to be composed of multiple layers.

[0062] A planarization layer 322, a filter layer 323, and a microlens 324 are disposed on the light incident side of the pinning film 321. The filter layer 323 may use various optical filters such as a color filter, an infrared light cut filter, and a monochrome filter. The color filter may use an RGB color filter, an RGBW color filter, or the like.

[0063] Each pixel 101 has sensitivity to a specific wavelength, such as visible light R (Red), G (Green), B (Blue), or NIR (Near InfraRed), depending on the spectral transmittance of the filter layer 323 disposed on the light incident side. Hereinafter, an example will be described in which the long wavelength in the pixel of this embodiment is the wavelength of near infrared light (780 to 3000 nm), and the short wavelength is the wavelength of visible light (380 to 780 nm).

[0064] For example, a pixel having a peak wavelength in visible light is used as an image capture pixel. Also, for example, a pixel having a peak wavelength in near-infrared light is used as a distance measurement pixel using ToF. The division into long wavelengths and short wavelengths (respective bands) in the present disclosure is not limited to this, and for example, a region with a long wavelength in the visible light region may be the long wavelength, or near-infrared light may be the short wavelength, and a region with a longer wavelength than near-infrared light may be the long wavelength.

[0065] The semiconductor layer 310 has a first semiconductor region 311 of N type, a fourth semiconductor region 314, a sixth semiconductor region 316, and a seventh semiconductor region 317. It further has a second semiconductor region 312, a third semiconductor region 313, and a fifth semiconductor region 315 of P type.

[0066] 7, an N-type first semiconductor region 311 is formed in the vicinity of a second surface facing the first surface (light incident surface), and an N-type fourth semiconductor region 314 is formed around the first semiconductor region 311. A P-type second semiconductor region 312 is formed at a position overlapping the first semiconductor region 311 and the fourth semiconductor region 314 in a planar view. An N-type seventh semiconductor region 317 is further disposed at a position overlapping the second semiconductor region 312 in a planar view, and an N-type sixth semiconductor region 316 is formed around the first semiconductor region 311.

[0067] The first semiconductor region 311 has a higher N-type impurity concentration than the fourth semiconductor region 314 and the seventh semiconductor region 317. A PN junction is formed between the P-type second semiconductor region 312 and the N-type first semiconductor region 311. By making the impurity concentration of the second semiconductor region 312 lower than the impurity concentration of the first semiconductor region 311, all regions of the second semiconductor region 312 that overlap with the center of the first semiconductor region in a planar view become depletion layer regions.

[0068] At this time, the potential difference between the first semiconductor region 311 and the second semiconductor region 312 becomes larger than the potential difference between the second semiconductor region 312 and the seventh semiconductor region 317. Furthermore, this depletion layer region extends to a partial region of the first semiconductor region 311, and a strong electric field is induced in the extended depletion layer region. This strong electric field causes avalanche multiplication in the depletion layer region extending to the partial region of the first semiconductor region 311, and a current based on the amplified charges is output as a signal charge. When light incident on the pixel 101 is photoelectrically converted and avalanche multiplication occurs in this depletion layer region (avalanche multiplication region), the generated charges are collected in the first semiconductor region 311.

[0069] 7, the fourth semiconductor region 314 and the seventh semiconductor region 317 are formed to have approximately the same size, but the size of each semiconductor region is not limited to this. For example, the seventh semiconductor region 317 may be formed to be larger than the fourth semiconductor region 314 so that charges are collected in the first semiconductor region 311 from a wider range.

[0070] Furthermore, the fourth semiconductor region 314 may be a P-type semiconductor region instead of an N-type. In this case, the impurity concentration of the fourth semiconductor region 314 is set to be lower than the impurity concentration of the second semiconductor region 312. If the impurity concentration of the fourth semiconductor region 314 is too high, an avalanche multiplication region is formed between the fourth semiconductor region 314 and the first semiconductor region 311, and the DCR (Dark Count Rate) increases.

[0071] Pixels are separated from one another by pixel separating portion 325 having a trench structure, and P-type third semiconductor region 313 formed around the pixel separating portion separates adjacent pixels by a potential barrier. Since pixels are also separated by the potential of fourth semiconductor region 314, a trench structure such as pixel separating portion 325 is not essential as a pixel separating portion, and even when pixel separating portion 325 having a trench structure is provided, its depth and position are not limited to the configuration in FIG.

[0072] The pixel separation section 325 may be a deep trench isolation (DTI) that penetrates the semiconductor layer 310, or may be a DTI that does not penetrate the semiconductor layer 310. A metal may be embedded in the DTI to improve light blocking performance. The pixel separation section 325 may be made of SiO, a fixed charge film, a metal member, Poly-Si, or a combination of a plurality of these. The pixel separation section 325 may be configured to surround the entire periphery of the pixel 101 in a plan view, or may be configured only on the opposite side of the pixel 101, for example. A voltage may be applied to the embedded member to induce a charge at the trench interface, thereby suppressing DCR.

[0073] The diffraction region 326 includes a plurality of recesses (first recesses) formed on the first surface (light incident surface) side of the fifth semiconductor region 315. The first recesses have a trench structure such as STI. An insulator such as SiO or SiN may be filled inside the recesses, or a metal such as W or Al may be filled inside the recesses. The diffraction region 326 is surrounded by the P-type fifth semiconductor region 315, and diffracts light incident on the pixel 101. Since the incident light travels obliquely inside the semiconductor layer 310, an optical path length equal to or greater than the thickness of the semiconductor layer 310 can be ensured, and more light can be photoelectrically converted than in the case where the diffraction region 326 is not provided.

[0074] The seventh semiconductor region 317 and the diffraction region 326 are formed to overlap in a plan view. The area where the seventh semiconductor region 317 and the diffraction region 326 overlap in a plan view is larger than the area of ​​a portion of the seventh semiconductor region 317 that does not overlap with the diffraction region 326.

[0075] Charges generated at a position far from the avalanche multiplication region formed between the first semiconductor region 311 and the seventh semiconductor region 317 take longer to travel to the avalanche multiplication region than charges generated at a position close to the avalanche multiplication region. This may increase timing jitter. By arranging the seventh semiconductor region 317 and the diffraction region 326 at positions where they overlap in a plan view, the electric field deep inside the photodiode can be increased and the collection time of charges generated at a position far from the avalanche multiplication region can be shortened, thereby reducing timing jitter.

[0076] Furthermore, the fifth semiconductor region 315 three-dimensionally covers the diffraction region 326, thereby making it possible to suppress the generation of thermally excited charges at the interface of the diffraction region 326. This suppresses the DCR of the pixel 101.

[0077] Here, the diffraction region 326 is provided only in long-wavelength pixels (first pixels) in which the incident light to the semiconductor layer 310 has a peak wavelength in the long wavelength region, and is not provided in short-wavelength pixels (second pixels) in which the incident light to the semiconductor layer 310 has a peak wavelength in the short wavelength region. For example, the diffraction region 326 is not provided for RGB pixels. The reason for this is that, although the effect of improving sensitivity by extending the optical path length is small because the penetration length of short-wavelength light into the semiconductor layer 310 is short, there is a concern that the diffraction region 326 will increase the number of silicon interfaces, thereby increasing dark current.

[0078] In the above description, the diffraction region is an example of a structure having a plurality of recesses formed by trench structures such as STI on the surface of the semiconductor layer 310, but the structure is not limited to this as long as it can diffract incident light.

[0079] As in this embodiment, the sensitivity can be improved by providing a diffraction region in a long-wavelength pixel (first pixel) for photoelectrically converting near-infrared light, and the effect of performance degradation due to the diffraction region can be avoided by not providing a diffraction region in a short-wavelength pixel (second pixel) for photoelectrically converting visible light.

[0080] Second Embodiment Fig. 8 is a schematic diagram showing an example of a pixel according to the second embodiment. The difference from the first embodiment in Fig. 7 is the shape of a plurality of recesses (first recesses) in the diffraction area 326. Hereinafter, a description of the same parts as in Fig. 7 will be omitted.

[0081] In the pixel of Fig. 7, a plurality of columnar recesses such as a trench structure are used in the diffraction region 326 of the long-wavelength pixel (first pixel), but in the second embodiment of Fig. 8, a structure having a plurality of quadrangular pyramid-shaped recesses is used in the diffraction region 326. The diffraction region 326 having such quadrangular pyramid-shaped recesses is formed by, for example, anisotropic wet etching. When the diffraction region 326 is formed by anisotropic wet etching, the surface of the diffraction region 326 becomes a (111) plane.

[0082] This structure also has the effect of improving the sensitivity in the long wavelength pixels (first pixels) like the structure shown in the first embodiment. Also, by not including a diffraction region in the short wavelength pixels (second pixels), it is possible to reduce the performance degradation caused by the diffraction region.

[0083] (Third embodiment) Fig. 9 is a schematic diagram showing an example of a pixel according to the third embodiment. The difference from the second embodiment in Fig. 8 is the shape of the diffraction region 326. Hereinafter, a description of the same parts as in Fig. 8 will be omitted.

[0084] In the pixel of FIG. 8, multiple pyramidal recesses are used in the diffraction region 326. In the pixel of FIG. 9, the interval between adjacent pyramidal recesses is different between the center and the periphery of the pixel. When the interval between adjacent pyramidal recesses in the center of the pixel is the most suitable interval for extending the optical path length, the effect of extending the optical path length of the diffraction region 326 is reduced in adjacent pyramidal recesses in the periphery of the pixel. In this way, crosstalk that may occur between multiple pixels 101 can be suppressed.

[0085] 9, the interval between the diffraction regions 326 in the periphery of the pixel is smaller than the interval between the diffraction regions 326 in the center of the pixel, but the relationship in size between the intervals between the recessed shapes may be reversed. In addition, in the above description, the diffraction region 326 has a quadrangular pyramid shape, but it may have a trench structure such as STI.

[0086] (Fourth embodiment) Fig. 10 is a schematic diagram showing an example of a pixel according to the fourth embodiment. The difference from the first embodiment in Fig. 7 is the location where the diffraction region 326 is provided. Hereinafter, a description of the same parts as in Fig. 7 will be omitted.

[0087] 10, the diffraction region 326 is also provided on the surface (second surface) opposite to the light incident surface (first surface) of the semiconductor layer 310. In this way, the optical path length can be further increased.

[0088] Fifth embodiment Fig. 11 is a schematic diagram showing an example of a pixel according to the fifth embodiment. The difference from the second embodiment in Fig. 8 is that the interval between adjacent recesses in the diffraction region 326 is made different for each pixel. Hereinafter, a description of the same parts as in Fig. 8 will be omitted.

[0089] 11, the interval between adjacent recesses in the diffraction region 326 is large in the long wavelength pixel (first pixel) and small in the short wavelength pixel (second pixel). Since the optimal interval of the diffraction region differs for each wavelength, a more suitable sensitivity improvement effect can be obtained by forming a pattern in which the interval between adjacent recesses in the diffraction region 326 is changed for each pixel having a different peak wavelength (or different color) of incident light, as shown in FIG.

[0090] Sixth embodiment Fig. 12 is a schematic diagram showing an example of a pixel according to the sixth embodiment. The difference from the first embodiment in Fig. 7 is that the diffraction region 326 is not provided in both the long wavelength pixel (first pixel) and the short wavelength pixel (second pixel), and the reflection reduction region 327 is provided in the short wavelength pixel out of the long wavelength pixel (first pixel) and the short wavelength pixel (second pixel). Hereinafter, the description of the same parts as in Fig. 7 will be omitted.

[0091] In FIG. 12, an AR (Anti-Reflection) region 327 having a plurality of recesses (second recesses) whose adjacent recesses are spaced apart from each other narrower than the adjacent recesses in the diffraction region 326 is provided on the light incident surface side of the semiconductor layer 310 as the reflection reduction region 327. The recesses in the AR region 327 and the intervals between adjacent recesses are set to be smaller than the wavelength of the incident light, and the change in the refractive index on the surface of the semiconductor layer 310 can be made gentler to obtain an AR effect (reflection reduction effect). In FIG. 12, the AR region 327 is provided only for the short wavelength pixel (second pixel), but it may also be provided for the long wavelength pixel (first pixel). Since the AR effect (reflection reduction effect) of the AR region 327 depends on the wavelength, it is preferable that the structure of the AR region 327 is adapted to the peak wavelength of the pixel.

[0092] Seventh embodiment 13 is a schematic diagram showing an example of a pixel according to the seventh embodiment. Hereinafter, a description of the same parts as those in the sixth embodiment in FIG. 12 will be omitted.

[0093] 13, a diffraction region 326 for the purpose of diffraction is provided in the long-wavelength pixel (first pixel), and an AR region 327 for the purpose of the AR effect is provided in the short-wavelength pixel (second pixel). In this way, it is possible to obtain a sensitivity improvement effect in the long-wavelength pixel (first pixel) and an AR effect in the short-wavelength pixel (second pixel).

[0094] Eighth embodiment 14 is a schematic diagram showing an example of a pixel according to the eighth embodiment. Hereinafter, a description of the same parts as those in FIG.

[0095] 14, a wiring layer in which wiring such as a cathode wiring 331 and an anode wiring 332 is arranged is provided on the second surface side of the semiconductor layer 310. The cathode wiring 331 is a wiring that supplies a voltage to one terminal (cathode terminal) of the APD, and the anode wiring 332 is a wiring that supplies a voltage to the other terminal (anode terminal) of the APD.

[0096] Light that enters the semiconductor layer 310 is photoelectrically converted in the semiconductor layer 310. A part of the incident light reaches the wiring layer 330 without being photoelectrically converted, and is reflected by the cathode wiring 331 and the anode wiring 332 arranged in the wiring layer, and returns to the semiconductor layer 310. Due to this reflection, even light that would not normally pass through the wiring layer 330 and be photoelectrically converted is photoelectrically converted in the semiconductor layer 310.

[0097] That is, the sensitivity of the photoelectric conversion device can be improved by providing a reflective metal (metal wiring) using the cathode wiring 331 and the anode wiring 332. In particular, the longer the wavelength of light that is less likely to be photoelectrically converted, the more likely it is that it will penetrate deep into the semiconductor layer 310, so the effect of improving sensitivity due to this reflective metal structure is significant.

[0098] In particular, in a SPAD, the cathode wiring 331 as a reflective metal is arranged under the avalanche multiplication region, so that it may be affected by the potential from the reflective metal. Also, since short-wavelength light has difficulty penetrating deep into the semiconductor layer 310, the reflective effect is small even if a reflective metal is arranged in the short-wavelength pixel (second pixel).

[0099] For the above reasons, in this embodiment, a reflective metal with a large area is placed only on the long-wavelength pixels (first pixels), and a reflective metal with a smaller area than the long-wavelength pixels (first pixels) is placed on the short-wavelength pixels (second pixels).

[0100] As a modification of this embodiment, a reflective metal having a large area is arranged only on the long wavelength pixels (first pixels), and no reflective metal is arranged on the short wavelength pixels (second pixels).

[0101] By doing this, reflection by the reflective metal can be efficiently performed for long-wavelength pixels (first pixels) in which the effect of the reflective metal is large, and the effect of the potential due to the reflective metal can be reduced for short-wavelength pixels (second pixels).

[0102] Ninth embodiment 15 is a schematic diagram showing an example of a pixel according to the ninth embodiment. Hereinafter, a description of the same parts as those in the first embodiment shown in FIG.

[0103] In the above embodiments, the structures are described in which the optical path length is extended by the diffraction region 326. However, extending the optical path length may increase the risk of crosstalk occurring between pixels.

[0104] 15, a connection portion 333 between the third semiconductor region 313 and the anode wiring 332 is shaped to surround the second semiconductor region 312 in a plan view. As shown in FIG. 15, this structure is preferably provided in a long-wavelength pixel (first pixel) in order to reduce long-wavelength light, which is a main cause of crosstalk, but may also be provided in a short-wavelength pixel (second pixel).

[0105] (Tenth embodiment) Any of the first to ninth embodiments can be applied to the tenth embodiment. Fig. 16(a) is a schematic diagram for explaining an apparatus 9191 including a semiconductor device 930 of this embodiment. The semiconductor device 930 can be a photoelectric conversion device (imaging device) of each of the above-mentioned embodiments.

[0106] An apparatus 9191 including a semiconductor device 930 will be described in detail. As described above, the semiconductor device 930 can include a package 920 that houses the semiconductor device 910, in addition to the semiconductor device 910 having the semiconductor layer 902. The package 920 can include a base to which the semiconductor device 910 is fixed, and a lid such as glass that faces the semiconductor device 910. The package 920 can further include a bonding member such as a bonding wire or a bump that connects a terminal provided on the base and a terminal provided on the semiconductor device 910.

[0107] The device 9191 can include at least one of an optical device 940, a control device 950, a processing device 960, a display device 970, a storage device 980, and a mechanical device 990. The optical device 940 corresponds to the semiconductor device 930. The optical device 940 is, for example, a lens, a shutter, or a mirror. The control device 950 controls the semiconductor device 930. The control device 950 is, for example, a semiconductor device such as an ASIC.

[0108] The processing device 960 processes the signal output from the semiconductor device 930. The processing device 960 is a semiconductor device such as a CPU or ASIC for configuring an AFE (analog front end) or a DFE (digital front end). The display device 970 is an EL display device or a liquid crystal display device that displays information (images) obtained by the semiconductor device 930. The storage device 980 is a magnetic device or a semiconductor device that stores information (images) obtained by the semiconductor device 930. The storage device 980 is a volatile memory such as an SRAM or a DRAM, or a non-volatile memory such as a flash memory or a hard disk drive.

[0109] The mechanical device 990 has a moving part or a propulsion part such as a motor or an engine. In the device 9191, the signal output from the semiconductor device 930 is displayed on the display device 970, or transmitted to the outside by a communication device (not shown) included in the device 9191. For this purpose, the device 9191 preferably further includes a memory device 980 and a processing device 960 in addition to the memory circuit and arithmetic circuit included in the semiconductor device 930. The mechanical device 990 may be controlled based on the signal output from the semiconductor device 930.

[0110] The device 9191 is also suitable for electronic devices such as information terminals (e.g., smartphones and wearable devices) with a photographing function and cameras (e.g., interchangeable lens cameras, compact cameras, video cameras, and surveillance cameras). The mechanical device 990 in the camera can drive components of the optical device 940 for zooming, focusing, and shutter operation. Alternatively, the mechanical device 990 in the camera can move the semiconductor device 930 for vibration isolation operation.

[0111] The device 9191 may be transportation equipment such as a vehicle, a ship, or an aircraft. The mechanical device 990 in the transportation equipment may be used as a moving device. The device 9191 as a transportation equipment is suitable for transporting the semiconductor device 930 or for assisting and / or automating driving (piloting) by using a photographing function. The processing device 960 for assisting and / or automating driving (piloting) can perform processing for operating the mechanical device 990 as a moving device based on information obtained by the semiconductor device 930. Alternatively, the device 9191 may be a medical device such as an endoscope, a measuring device such as a distance measuring sensor, an analytical device such as an electron microscope, an office machine such as a copier, or an industrial device such as a robot.

[0112] According to the above-described embodiment, it is possible to obtain good pixel characteristics. Therefore, the value of the semiconductor device can be increased. In this case, increasing the value corresponds to at least one of adding functions, improving performance, improving characteristics, improving reliability, improving manufacturing yield, reducing environmental load, reducing costs, reducing size, and reducing weight.

[0113] Therefore, if the semiconductor device 930 according to this embodiment is used in the equipment 9191, the value of the equipment can be improved. For example, by mounting the semiconductor device 930 on a transport equipment, excellent performance can be obtained when photographing the outside of the transport equipment or measuring the external environment. Therefore, in manufacturing and selling the transport equipment, it is advantageous to decide to mount the semiconductor device according to this embodiment on the transport equipment in order to improve the performance of the transport equipment itself. In particular, the semiconductor device 930 is suitable for transport equipment that performs driving assistance and / or automatic driving of the transport equipment using information obtained by the semiconductor device.

[0114] The photoelectric conversion system and the moving object of this embodiment will be described with reference to FIGS.

[0115] Fig. 16(b) shows an example of a photoelectric conversion system related to an in-vehicle camera. The photoelectric conversion system 8000 has a photoelectric conversion device 80. The photoelectric conversion device 80 is the photoelectric conversion device (imaging device) described in any of the above embodiments. The photoelectric conversion system 8000 has an image processing unit 801 that performs image processing on a plurality of image data acquired by the photoelectric conversion device 80, and a parallax acquisition unit 802 that calculates parallax (phase difference of parallax images) from the plurality of image data acquired by the photoelectric conversion system 8000.

[0116] The photoelectric conversion system 8000 also includes a distance acquisition unit 803 that calculates the distance to the object based on the calculated parallax, and a collision determination unit 804 that determines whether or not there is a possibility of collision based on the calculated distance. Here, the parallax acquisition unit 802 and the distance acquisition unit 803 are examples of distance information acquisition means that acquire information on the distance to the object. That is, the distance information is information on the parallax, the defocus amount, the distance to the object, and the like. The collision determination unit 804 may determine the possibility of collision using any of these pieces of distance information.

[0117] The distance information acquisition means may be realized by dedicated hardware, a software module, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), or a combination of these.

[0118] The photoelectric conversion system 8000 is connected to a vehicle information acquisition device 810 and can acquire vehicle information such as vehicle speed, yaw rate, steering angle, etc. The photoelectric conversion system 8000 is also connected to a control ECU 820, which is a control device that outputs a control signal for generating a braking force for the vehicle based on the determination result of the collision determination unit 804. The photoelectric conversion system 8000 is also connected to an alarm device 830 that issues an alarm to the driver based on the determination result of the collision determination unit 804.

[0119] For example, when the collision probability is high as a result of the judgment by the collision judgment unit 804, the control ECU 820 performs vehicle control to avoid the collision and reduce damage by applying the brakes, releasing the accelerator, suppressing the engine output, etc. The warning device 830 warns the user by sounding a warning, displaying warning information on the screen of a car navigation system, etc., applying vibrations to the seat belt or steering wheel, etc.

[0120] In this embodiment, the surroundings of the vehicle, for example, the front or rear, are imaged by the photoelectric conversion system 8000. Fig. 16(c) shows a photoelectric conversion system for imaging the area in front of the vehicle (imaging range 850). A vehicle information acquisition device 810 sends an instruction to the photoelectric conversion system 8000 or the photoelectric conversion device 80. This configuration can further improve the accuracy of distance measurement.

[0121] Although an example of control to prevent collision with other vehicles has been described above, the present invention can also be applied to control of automatic driving by following other vehicles, control of automatic driving to prevent deviation from lanes, and the like. Furthermore, the photoelectric conversion system is not limited to vehicles such as the vehicle itself, but can be applied to moving bodies (moving devices) such as ships, aircraft, and industrial robots. For example, the present invention may have a moving body equipped with the photoelectric conversion device described in each embodiment, and a control unit that controls the movement of the moving body using a signal output by the photoelectric conversion device. In addition, the present invention can be applied not only to moving bodies, but also to a wide range of devices that use object recognition, such as an intelligent transport system (ITS).

[0122] (Other embodiments) It should be noted that the above-mentioned embodiments are merely examples of the implementation of the present disclosure, and the technical scope of the present disclosure should not be interpreted as being limited by these. In other words, the present disclosure can be implemented in various forms without departing from its technical concept or main features. For example, combinations of the elements of the above-mentioned embodiments are also within the scope of the present disclosure.

[0123] In addition, each of the embodiments described above can be appropriately modified without departing from the scope of the technical concept. The disclosure of this specification includes not only what is described in this specification, but also all matters that can be understood from this specification and the drawings attached to this specification.

[0124] The disclosure of this embodiment includes the following configurations and methods.

[0125] (Configuration 1) a plurality of pixels each including an avalanche photodiode; the plurality of pixels include a first pixel and a second pixel that photoelectrically converts incident light including light having a wavelength shorter than a wavelength of the incident light that is photoelectrically converted by the first pixel; A diffraction region for diffracting incident light is provided in the first pixel and not provided in the second pixel. A photoelectric conversion device comprising:

[0126] (Configuration 2) The photoelectric conversion device according to configuration 1, wherein the diffraction region has a first recess consisting of a plurality of recesses formed on a first surface, which is a light incident surface of a semiconductor layer having the avalanche photodiode provided thereon.

[0127] (Configuration 3) the second pixel includes a reflection reducing region having a second recess that is made up of a plurality of recesses that reduce reflection of incident light; 3. The photoelectric conversion device according to configuration 2, wherein the second recesses are spaced apart from one another by a narrower distance than the first recesses.

[0128] (Configuration 4) 4. The photoelectric conversion device according to any one of configurations 1 to 3, further comprising a wiring layer on a second surface side opposite to a first surface which is a light incident surface of the semiconductor layer having the avalanche photodiode provided thereon.

[0129] (Configuration 5) the wiring layer includes a reflective metal that reflects incident light, 5. The photoelectric conversion device according to configuration 4, wherein, in a plan view, the reflective metal overlapping the first pixel has a larger area than the reflective metal overlapping the second pixel.

[0130] (Configuration 6) the semiconductor layer in which the avalanche photodiode is provided has a semiconductor region provided between the plurality of pixels, In the first pixel, a connection portion between the semiconductor region and a wiring provided in the wiring layer is provided in a shape surrounding the avalanche photodiode in a plan view. 6. The photoelectric conversion device according to configuration 4 or 5,

[0131] (Configuration 7) 7. The photoelectric conversion device according to any one of configurations 2 to 6, wherein the intervals between the plurality of recesses of the first recess are different between a central portion and a peripheral portion of the pixel.

[0132] (Configuration 8) 8. The photoelectric conversion device according to configuration 7, wherein the intervals between the plurality of recesses of the first recess are narrower in the periphery of the pixel than in the center of the pixel.

[0133] (Configuration 9) 8. The photoelectric conversion device according to configuration 7, wherein the intervals between the plurality of recesses of the first recess are wider in the periphery of the pixel than in the center of the pixel.

[0134] (Configuration 10) The optical element further includes a diffraction region different from the diffraction region, the diffraction region being provided on a second surface side opposite to the first surface, The different diffraction region is provided in the first pixel and is not provided in the second pixel in a plan view. 10. The photoelectric conversion device according to any one of configurations 2 to 9, characterized in that:

[0135] (Configuration 11) The photoelectric conversion device according to any one of configurations 1 to 10, wherein the second pixel has a reflection reduction region for reducing reflection of incident light on the side of a first surface, which is a light incident surface of a semiconductor layer having the avalanche photodiode.

[0136] (Configuration 12) 12. The photoelectric conversion device according to any one of configurations 2 to 11, wherein the first recess has a plurality of recesses each having a trench structure.

[0137] (Configuration 13) 12. The photoelectric conversion device according to any one of configurations 2 to 11, wherein the first recess has a plurality of recesses each having a quadrangular pyramid shape.

[0138] (Configuration 14) 14. The photoelectric conversion device according to any one of configurations 2 to 13, wherein an insulator is disposed in a plurality of recesses of the first recess.

[0139] (Configuration 15) 14. The photoelectric conversion device according to any one of configurations 2 to 13, wherein a metal is disposed in a plurality of recesses of the first recess.

[0140] (Configuration 16) 16. The photoelectric conversion device according to any one of configurations 1 to 15, wherein a wavelength at which the first pixel has a peak sensitivity is near-infrared light.

[0141] (Configuration 17) 17. The photoelectric conversion device according to any one of configurations 1 to 16, wherein a wavelength at which the second pixel has a peak sensitivity is visible light.

[0142] (Configuration 18) a plurality of pixels each including an avalanche photodiode; and a wiring layer disposed on a second surface side facing a first surface that is a light incident surface of a semiconductor layer in which the avalanche photodiode is provided; the plurality of pixels include a first pixel and a second pixel that photoelectrically converts incident light including light having a wavelength shorter than a wavelength of the incident light that is photoelectrically converted by the first pixel; the wiring layer includes a reflective metal that reflects incident light, In a plan view, the reflective metal overlapping the first pixel has an area larger than that of the reflective metal overlapping the second pixel. A photoelectric conversion device comprising:

[0143] (Configuration 19) The semiconductor layer includes a first surface on which the avalanche photodiode is provided, and a reflection reducing region that reduces reflection of incident light and is provided on the first surface side of the semiconductor layer on which the avalanche photodiode is provided, the first surface being a light incident surface of the semiconductor layer. the plurality of pixels include a first pixel and a second pixel that photoelectrically converts incident light including light having a wavelength shorter than a wavelength of the incident light that is photoelectrically converted by the first pixel; The reflection reducing area is provided in the first pixel and is not provided in the second pixel. A photoelectric conversion device comprising:

[0144] (Configuration 20) A plurality of pixels each including a photoelectric conversion element; the plurality of pixels include a first pixel and a second pixel that photoelectrically converts incident light including light having a wavelength shorter than a wavelength of the incident light that is photoelectrically converted by the first pixel; A diffraction region for diffracting incident light is provided in the first pixel and not provided in the second pixel. A photoelectric conversion device comprising:

[0145] (Configuration 21) An apparatus including the photoelectric conversion device according to any one of configurations 1 to 20, an optical device corresponding to the photoelectric conversion device; A control device for controlling the photoelectric conversion device; a processing device that processes a signal output from the photoelectric conversion device; a display device that displays information obtained by the photoelectric conversion device; a storage device that stores information obtained by the photoelectric conversion device; and and a mechanical device that operates based on information obtained by the photoelectric conversion device.

[0146] (Configuration 22) A moving object including the photoelectric conversion device according to any one of configurations 1 to 20, A moving body comprising: a control unit that controls the movement of the moving body using a signal output from the photoelectric conversion device. [Explanation of symbols]

[0147] 100 Photoelectric conversion device 101 pixels 102 Photoelectric conversion unit (avalanche photodiode) 326 Diffraction Area

Claims

1. a plurality of pixels each including an avalanche photodiode; the plurality of pixels include a first pixel and a second pixel that photoelectrically converts incident light including light having a wavelength shorter than a wavelength of the incident light that is photoelectrically converted by the first pixel; A diffraction region for diffracting incident light is provided in the first pixel and not provided in the second pixel. A photoelectric conversion device comprising:

2. 2. The photoelectric conversion device according to claim 1, wherein the diffraction region has a first recess consisting of a plurality of recesses formed in a first surface, which is a light incidence surface of a semiconductor layer having the avalanche photodiode provided thereon.

3. the second pixel includes a reflection reducing region having a second concave portion including a plurality of concave portions that reduce reflection of incident light; The photoelectric conversion device according to claim 2 , wherein the second recesses are spaced apart from one another by a narrower distance than the first recesses.

4. 2. The photoelectric conversion device according to claim 1, further comprising a wiring layer on a second surface side opposite to a first surface which is a light incidence surface of the semiconductor layer on which the avalanche photodiode is provided.

5. the wiring layer includes a reflective metal that reflects incident light, 5. The photoelectric conversion device according to claim 4, wherein, in a plan view, the reflective metal overlapping the first pixel has an area larger than that of the reflective metal overlapping the second pixel.

6. the semiconductor layer in which the avalanche photodiode is provided has a semiconductor region provided between the plurality of pixels, In the first pixel, a connection portion between the semiconductor region and a wiring provided in the wiring layer is provided in a shape surrounding the avalanche photodiode in a plan view.

5. The photoelectric conversion device according to claim 4,

7. 3 . The photoelectric conversion device according to claim 2 , wherein the intervals between the plurality of recesses in the first recess are different between a central portion and a peripheral portion of the pixel.

8. 8. The photoelectric conversion device according to claim 7, wherein the intervals between the plurality of recesses of the first recess are narrower in a peripheral portion of the pixel than in a central portion of the pixel.

9. 8. The photoelectric conversion device according to claim 7, wherein the intervals between the plurality of recesses of the first recess are wider in a peripheral portion of the pixel than in a central portion of the pixel.

10. The optical element further includes a diffraction region different from the diffraction region, the diffraction region being provided on a second surface side opposite to the first surface, The different diffraction region is provided in the first pixel and is not provided in the second pixel in a plan view.

3. The photoelectric conversion device according to claim 2 .

11. 2. The photoelectric conversion device according to claim 1, wherein the second pixel has a reflection reduction region for reducing reflection of incident light on a side of a first surface, which is a light incident surface of a semiconductor layer having the avalanche photodiode.

12. The photoelectric conversion device according to claim 2 , wherein the first recess has a plurality of recesses each having a trench structure.

13. The photoelectric conversion device according to claim 2 , wherein the first recess has a plurality of recesses each having a quadrangular pyramid shape.

14. The photoelectric conversion device according to claim 2 , wherein an insulator is disposed in a plurality of recesses of the first recess.

15. The photoelectric conversion device according to claim 2 , wherein a metal is disposed in a plurality of recesses of the first recess.

16. 2. The photoelectric conversion device according to claim 1, wherein the wavelength at which the first pixel has a peak sensitivity is near-infrared light.

17. 2. The photoelectric conversion device according to claim 1, wherein the wavelength at which the second pixel has a peak sensitivity is visible light.

18. a wiring layer disposed on a second surface side facing a first surface that is a light incidence surface of a semiconductor layer on which the avalanche photodiode is provided; the plurality of pixels include a first pixel and a second pixel that photoelectrically converts incident light including light having a wavelength shorter than a wavelength of the incident light that is photoelectrically converted by the first pixel; the wiring layer includes a reflective metal that reflects incident light, In a plan view, the reflective metal overlapping the first pixel has an area larger than that of the reflective metal overlapping the second pixel. A photoelectric conversion device comprising:

19. a reflection reducing region for reducing reflection of incident light provided on a first surface side of a semiconductor layer on which the avalanche photodiode is provided, the first surface being a light incident surface of the semiconductor layer; the plurality of pixels include a first pixel and a second pixel that photoelectrically converts incident light including light having a wavelength shorter than a wavelength of the incident light that is photoelectrically converted by the first pixel; The reflection reducing area is provided in the first pixel and is not provided in the second pixel. A photoelectric conversion device comprising:

20. A plurality of pixels each including a photoelectric conversion element; the plurality of pixels include a first pixel and a second pixel that photoelectrically converts incident light including light having a wavelength shorter than a wavelength of the incident light that is photoelectrically converted by the first pixel; A diffraction region for diffracting incident light is provided in the first pixel and not provided in the second pixel. A photoelectric conversion device comprising:

21. An apparatus comprising the photoelectric conversion device according to any one of claims 1 to 20, an optical device corresponding to the photoelectric conversion device; A control device for controlling the photoelectric conversion device; a processing device that processes a signal output from the photoelectric conversion device; a display device that displays information obtained by the photoelectric conversion device; a storage device that stores information obtained by the photoelectric conversion device; and and a mechanical device that operates based on information obtained by the photoelectric conversion device.

22. A moving object comprising the photoelectric conversion device according to any one of claims 1 to 20, A moving body comprising: a control unit that controls the movement of the moving body using a signal output from the photoelectric conversion device.

Images