Photoelectric conversion device, and system using the photoelectric conversion device

Abstract

To prevent generation of noise due to mismatch of lattices on a junction interface of dissimilar materials.SOLUTION: A photoelectric conversion device has a semiconductor substrate formed of a first material and having an avalanche photodiode, and a photoelectric conversion layer formed of a second material having a smaller band gap than the first material. The photoelectric conversion device has a region in contact with the semiconductor substrate and the photoelectric conversion layer, and formed of a third material including at least an element of the first material or the second material. In a top view, an area of the region is smaller than an area of the photoelectric conversion layer.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] As disclosed in Patent Document 1, a method is disclosed in which a Ge absorption layer is disposed directly on an avalanche photodiode formed of Si, and photons are photoelectrically converted within the absorption layer, thereby improving near-infrared sensitivity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2022-500882 Summary of the Invention [Problem to be solved by the invention]

[0004] At the interface between materials with different lattice constants, noise can increase due to lattice mismatch. [Means for solving the problem]

[0005] One aspect of the present invention is a photoelectric conversion device comprising: a semiconductor substrate made of a first material and having an avalanche photodiode; and a photoelectric conversion layer made of a second material having a smaller band gap than the first material, and a region in contact with the semiconductor substrate and the photoelectric conversion layer and made of a third material containing at least elements of the first material or the second material, wherein, in a top view, the area of ​​the region is smaller than the area of ​​the photoelectric conversion layer. Effect of the Invention

[0006] According to the present invention, noise at the bonding interface between different materials can be suppressed. [Brief description of the drawings]

[0007] [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 PD 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 plan view of a pixel according to the first embodiment. [Figure 7] FIG. 2 is a cross-sectional view of a pixel according to the first embodiment. [Figure 8] FIG. 11 is a cross-sectional view of a pixel according to a second embodiment. [Figure 9] FIG. 11 is a cross-sectional view of a pixel according to a third embodiment. [Figure 10] FIG. 13 is a cross-sectional view of a pixel according to a fourth embodiment. [Figure 11] FIG. 13 is a cross-sectional view of a pixel according to a fifth embodiment. [Figure 12] FIG. 13 is a cross-sectional view of a pixel according to a sixth embodiment. [Figure 13] FIG. 13 is a cross-sectional view of a pixel according to a seventh embodiment. [Figure 14] FIG. 13 is a plan view of a pixel according to the seventh embodiment. [Figure 15] FIG. 13 is a cross-sectional view of a pixel according to an eighth embodiment. [Figure 16] FIG. 13 is a functional block diagram of a photoelectric conversion system according to a ninth embodiment. [Figure 17] FIG. 23 is a functional block diagram of a photoelectric conversion system according to a tenth embodiment. [Figure 18] FIG. 23 is a functional block diagram of a photoelectric conversion system according to an eleventh embodiment. [Figure 19] FIG. 23 is a functional block diagram of a photoelectric conversion system according to a twelfth embodiment. [Figure 20]FIG. 23 is a functional block diagram of a photoelectric conversion system according to a thirteenth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 1 is a diagram showing the configuration of a stacked photoelectric conversion device according to an embodiment of the present invention. The photoelectric conversion device 100 is configured by stacking and electrically connecting two chips, a sensor chip 11 and a circuit chip 21.

[0009] The sensor chip 11 has a pixel region 12 arranged thereon, and the circuit chip 21 has a circuit region 22 arranged thereon for processing signals detected in the pixel region 12 .

[0010] 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. The pixels 101 are typically pixels for forming an image, but when used for TOF (Time of Flight), they do not necessarily need to form an image. In other words, the pixels 101 may be pixels for measuring the time when light arrives and the amount of light.

[0011] 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.

[0012] The photoelectric conversion layer 102 in FIG. 2 and the signal processing unit 103 in FIG. 3 are electrically connected via connection wiring provided for each pixel.

[0013] 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.

[0014] The signal output from the photoelectric conversion unit 102 of each pixel is processed by the signal processing unit 103. The signal processing unit 103 is provided with a counter, a memory, etc., and digital values ​​are stored in the memory. The horizontal scanning circuit unit 111 inputs a control pulse to the signal processing unit 103 for sequentially selecting each column in order to read out the signal from the memory of each pixel in which the digital signal is stored. 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.

[0015] 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 .

[0016] 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.

[0017] FIG. 4 is an example of a block diagram including the equivalent circuits of FIG. 2 and FIG. 3. In FIG. 2, the photoelectric conversion unit 102 having the APD 201 is provided on the sensor chip 11, and other members are provided on the circuit chip 21. The APD 201 generates a pair of charges according to 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 is supplied to the anode and cathode such that the APD 201 performs avalanche multiplication. By supplying such a voltage, the charges generated by the incident light undergo avalanche multiplication, generating an avalanche current.

[0018] When a reverse bias voltage is supplied, there are two modes: Geiger mode, which operates with the potential difference between the anode and cathode greater than the breakdown voltage, and linear mode, which operates with the potential difference between the anode and cathode close to or less than the breakdown voltage. An APD that operates in Geiger mode is called a SPAD. For example, the voltage VL (first voltage) is -30V, and the voltage VH (second voltage) is 1V.

[0019] The quench element 202 is connected to a power supply that supplies a voltage VH and the APD 201. The quench element 202 has a function of converting a change in avalanche current occurring in the APD 201 into a voltage signal. The quench element 202 functions as a load circuit (quench circuit) during signal multiplication by avalanche multiplication, and has a function of suppressing avalanche multiplication by suppressing the voltage supplied to the APD 201 (quench operation).

[0020] 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 any one of the waveform shaping section 210, the counter circuit 211, and the selection circuit 212.

[0021] 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. For example, an inverter circuit is used as the waveform shaping unit 210. Although an example in which one inverter is used as the waveform shaping unit 210 is shown in Fig. 4, a circuit in which a plurality of inverters are connected in series may be used, or another circuit having a waveform shaping effect may be used.

[0022] The counter circuit 211 counts and holds the count value of the pulse signal output from the waveform shaping unit 210. When a control pulse pRES is supplied via a drive line 213, the signal held in the counter circuit 211 is reset.

[0023] 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.

[0024] The electrical connection may be switched by disposing a switch such as a transistor between the quench element 202 and the APD 201 or between the photoelectric conversion layer 102 and the signal processing unit 103. Similarly, the supply of the voltage VH or the voltage VL to the photoelectric conversion layer 102 may be electrically switched using a switch such as a transistor.

[0025] In this embodiment, a configuration using the counter circuit 211 has been shown. However, instead of the counter circuit 211, a photoelectric conversion device 100 may be configured to acquire the pulse detection timing using a time-to-digital converter (hereinafter, TDC) and a memory. In this case, the generation timing of the pulse signal output from the waveform shaping unit 210 is converted into a digital signal by the TDC. To measure the timing of the pulse signal, a control pulse pREF (reference signal) is supplied to the TDC from the vertical scanning circuit unit 110 in FIG. 1 via a drive line. The TDC acquires, as a digital signal, a signal obtained by converting the input timing of the signal output from each pixel via the waveform shaping unit 210 into a relative time based on the control pulse pREF.

[0026] Fig. 5 is a diagram showing a schematic diagram of the relationship between the operation of the APD and the output signal. Fig. 5(a) is a diagram showing the APD 201, the quench element 202, and the waveform shaping unit 210 of Fig. 2. Here, the input side of the waveform shaping unit 210 is called nodeA, and the output side is called nodeB. Fig. 5(b) shows the waveform change of nodeA in Fig. 5(a), and Fig. 5(c) shows the waveform change of nodeB in Fig. 5(a).

[0027] Between times t0 and t1, a potential difference of VH-VL is applied to the APD 201 in FIG. 5(a).

[0028] When a photon is incident at time t1, an avalanche multiplication current flows through the quench element 202, and the voltage at nodeA drops. When the amount of voltage drop increases further and the potential difference applied to the APD 201 decreases, avalanche multiplication in the APD 201 stops, and the voltage level at nodeA does not drop below a certain value. After that, a current that compensates for the voltage drop from voltage VH flows through nodeA, and at time t3, nodeA is stabilized to its original potential level.

[0029] At this time, the portion of the output waveform at nodeA that exceeds a certain threshold value is waveform-shaped by the waveform shaping section 210 and is output as a signal at nodeB.

[0030] (First embodiment) A photoelectric conversion device according to a first embodiment will be described with reference to FIG. 6 and FIG.

[0031] Fig. 6 is a plan view of two pixels of a photoelectric conversion device according to the first embodiment. Fig. 7 is a cross-sectional view of two pixels of a photoelectric conversion device taken along the line A-A' in Fig. 6. The numbers given to the semiconductor regions and structures in Fig. 7 are the same as those in Fig. 6. For ease of explanation, the plan view in Fig. 6 also shows see-through portions of each part to show the positional relationship of each part.

[0032] The regions surrounded by dotted lines in Figs. 6 and 7 are pixels 101. As shown in Fig. 6, each of the pixels 101 is electrically isolated from adjacent pixels by an isolation trench 316. A fifth semiconductor region 315 is provided at a diagonal position of each pixel, and a fourth semiconductor region 314 is arranged inside the isolation trench 316. A first semiconductor region 311, a second semiconductor region 312, and a third semiconductor region 313 are arranged concentrically in the semiconductor substrate. A cylindrical columnar structure 322 is arranged concentrically with the first semiconductor region 311 on the light incident surface side of the semiconductor substrate.

[0033] As shown in FIG. 7, the pixel 101 has a structure in which a semiconductor substrate 300, a photoelectric conversion layer 301, and a wiring layer 302 are laminated in a cross-sectional view. The semiconductor substrate 300 is made of a first material and has a first surface 303 and a second surface 304. The semiconductor substrate 300 is laminated with the photoelectric conversion layer 301 so that the first surface 303 faces a seventh surface 307 of the photoelectric conversion layer 301. The photoelectric conversion layer 301 has a third surface 305 facing the seventh surface 307. Furthermore, the semiconductor substrate 300 is laminated with the wiring layer 302 so that the second surface 304 faces an eighth surface 308 of the wiring layer 302, and the wiring layer 302 has a fourth surface 306 facing the eighth surface 308. In this embodiment, the third surface 305 is a light incident surface.

[0034] The semiconductor substrate 300 is made of a first material, and has a first semiconductor region 311 of a first conductivity type on the second surface 304 side, and a second semiconductor region 312 of a second conductivity type on the first surface 303 side of the first semiconductor region 311. A third semiconductor region 313 of the first conductivity type is provided around the first semiconductor region 311, and the semiconductor substrate 300 further has a fourth semiconductor region 314 of a second conductivity type and a fifth semiconductor region 315 of the second conductivity type. An isolation trench 316 is provided between the pixels 101.

[0035] A voltage VH (first voltage) is applied to the first conductivity type first semiconductor region 311. Meanwhile, a voltage VL (second voltage) is supplied to the second conductivity type fifth semiconductor region 315, and the voltage VL is also applied to the second conductivity type second semiconductor region 312 through the second conductivity type fourth semiconductor region 314. An avalanche multiplication region is formed in a region where the first conductivity type first semiconductor region 311 and the second conductivity type second semiconductor region 312 are adjacent to each other.

[0036] By supplying such a voltage, avalanche multiplication occurs when charges generated by incident light pass through the avalanche region, generating an avalanche current. The fourth semiconductor region 314 of the second conductivity type serves as an isolation region between adjacent pixels.

[0037] In order to reduce the contact resistance between the semiconductor substrate 300 and the wiring layer 302, a fifth semiconductor region 315 of the second conductivity type is disposed on the second surface 304 side of the semiconductor substrate 300 at the diagonal corner of the pixel 101. At this time, the impurity concentration of the second conductivity type in the fifth semiconductor region 315 is higher than the impurity concentration of the second conductivity type in the fourth semiconductor region 314. The sidewall of the isolation trench 316 is covered by the fourth semiconductor region 314, and the isolation trench 316 prevents light in the pixel from crosstalking to adjacent pixels. In addition, the third semiconductor region 313 of the first conductivity type is disposed so as to cover the corner of the first semiconductor region 311 of the first conductivity type, and suppresses the formation of a local high electric field region between the first semiconductor region 311 of the first conductivity type and the fifth semiconductor region 315 of the second conductivity type.

[0038] The photoelectric conversion layer 301 is made of a second material and has a photoelectric conversion region 321. The second material has a smaller band gap than the first material and has a higher quantum efficiency in the near-infrared wavelength band than the first material. In general, a semiconductor can photoelectrically convert light having energy exceeding the band gap energy. Since the band gap of the second material is smaller than the band gap of the first material, the energy required for photoelectric conversion is also small. In other words, the second material can photoelectrically convert light having a longer wavelength than light that can be photoelectrically converted by the first material. The first material is, for example, Si, and the second material is, for example, Ge. Ge may be used as an intrinsic semiconductor, or may be an impurity semiconductor doped with impurities such as phosphorus (P), arsenic (As), antimony (Sb), boron (B), aluminum (Al), or gallium (Ga). The second material is not limited to Ge, and may be, for example, InGaAs (indium gallium arsenide) or GeSn (germanium tin). In this embodiment, a diode formed by a PN junction between the first semiconductor region 311 and the second semiconductor region 312 and the photoelectric conversion region 321 are combined together to form one APD.

[0039] A predetermined voltage is applied to the photoelectric conversion region 321. The voltage applied to the photoelectric conversion region 321 will be described in detail later.

[0040] Between the semiconductor substrate 300 and the photoelectric conversion layer 301, a columnar structure 322 of a third material is disposed.

[0041] Since the first material constituting the semiconductor substrate 300 and the second material constituting the photoelectric conversion region 321 have different atomic lattice distances, misfit dislocations due to lattice mismatch may occur at the bonding interface when the semiconductor substrate 300 and the photoelectric conversion region 321 are bonded together. There is a concern that the generated misfit dislocations may become a leak current source, thereby worsening noise.

[0042] In this embodiment, a columnar structure 322 of a third material having an area smaller than that of the photoelectric conversion region 321 is disposed between the semiconductor substrate 300 of the first material and the photoelectric conversion region 321 of the second material. This reduces the bonding area of ​​the members of different materials compared to the case where the semiconductor substrate 300 and the photoelectric conversion region 321 are directly bonded, and the influence of lattice mismatch at the bonding interface is suppressed. In a cross-sectional view, one columnar structure 322 is disposed per pixel, and the width of the columnar structure 322 is narrower than the width of the photoelectric conversion region 321. The third material includes at least the first material or the second material. The material constituting the columnar structure 322 can have the effect of suppressing the influence of photon mismatch regardless of whether it is the first material or the second material, but it is desirable that the bonding area be as small as possible. In particular, it is more preferable to use the second material for the columnar structure 322 because dislocation defects occurring from the bonding interface with the semiconductor substrate 300 of the first material can be terminated within the region of the columnar structure 322. On the other hand, even if the columnar structures 322 are made of only the first material, by making the junction area of ​​the interface smaller than the area of ​​the photoelectric conversion region 321, the effect of suppressing noise generation can be obtained.

[0043] The columnar structure 322 does not have to be arranged so as to overlap with the avalanche multiplication region when viewed from above. Although not shown in FIG. 7, a heterojunction for drawing out hole charges is provided between the photoelectric conversion region 321 and the fourth semiconductor region 314 of the second conductivity type in addition to the columnar structure 322. An anode voltage VL is supplied to the photoelectric conversion region 321 via the fourth semiconductor region 314 of the second conductivity type, and charges are induced. The heterojunction may have a columnar structure to reduce its junction area, and may have wiring on the third surface 305 side of the photoelectric conversion region 321.

[0044] Second embodiment A photoelectric conversion device according to the second embodiment will be described with reference to Fig. 8. Descriptions common to the first embodiment will be omitted, and differences from the first embodiment will be mainly described.

[0045] Fig. 8 is a cross-sectional view of a pixel of a photoelectric conversion device according to the second embodiment. In Fig. 8, a sixth semiconductor region 323 of a second material is disposed on the third surface 305 side of a photoelectric conversion region 321, and an anode voltage is supplied to the sixth semiconductor region 323 via an anode contact 324 and a metal wiring 325. Each pixel has a microlens 330. As in Fig. 6, the photoelectric conversion region 321 is disposed in a quadrangle in a top view on the semiconductor substrate 300, and anode contacts 324 are disposed at the four corners. In addition, a columnar structure 322 of a third material includes at least the second material.

[0046] The configuration shown in this embodiment is different from the configuration shown in the first embodiment in that a metal wiring 325 is provided on the third surface 305 side of the photoelectric conversion region 321, and a voltage VL2 (third voltage) is applied to the photoelectric conversion region 321 via the anode contact 324. At this time, the charge generated by photoelectric conversion in the photoelectric conversion region 321 moves to the semiconductor substrate 300 through the columnar structure 322 of the third material. The metal wiring 325 is a mesh-like wiring that covers the gap between the pixels 101 on the third surface 305 side, and prevents light from entering the region other than the photoelectric conversion region 321, thereby preventing optical crosstalk between the pixels. The metal wiring 325 shown in FIG. 8 is assumed to be configured so that the metal wiring 325 extends to surround each of the pixels 101, but the metal wiring 325 may be provided so as to surround a plurality of pixels 101 (for example, four pixels).

[0047] Here, the voltage VL2 supplied to the photoelectric conversion region 321 via the metal wiring 325 may be equal to the anode voltage VL applied to the fifth semiconductor region 315 and the second semiconductor region 312, or may be a voltage lower than the anode voltage VL. For the transfer of charges generated in the photoelectric conversion region, it is preferable that a potential gradient is formed from the photoelectric conversion region 321 of the second semiconductor material toward the first semiconductor region 311.

[0048] 8 differs from the first embodiment in that it has a pinning film 320 and a microlens 330. The pinning film 320 disposed on the first surface 303 can suppress noise generated from the junction interface. Furthermore, by disposing a microlens on the third surface 305, light can be collected in the photoelectric conversion region 321, improving sensitivity. In FIG. 9, the microlens 330 is provided at the center of each pixel, but the arrangement of the microlens is not limited thereto, and the center of the microlens may be shifted from the center of the pixel depending on the relative position of each pixel in the pixel array.

[0049] (Third embodiment) A photoelectric conversion device according to the third embodiment will be described with reference to Fig. 9. Descriptions common to the photoelectric conversion devices according to the first and second embodiments will be omitted, and differences from the photoelectric conversion device according to the second embodiment will be mainly described.

[0050] Fig. 9 is a cross-sectional view of a pixel of a photoelectric conversion device according to a third embodiment. Fig. 9 differs from Fig. 8 in that a transparent electrode 326 is arranged on the third surface 305 side of a photoelectric conversion region 321 and that a semiconductor substrate 300 has a charge collecting region 317. Furthermore, it differs from the configuration in Fig. 8 in that a columnar structure 322 of a third material extends from the first surface 303 into the semiconductor substrate 300.

[0051] In the configuration shown in FIG. 8, since the metal wiring 325 is provided on the light incident surface side of the semiconductor substrate, there is a possibility that a part of the light heading for the semiconductor substrate is blocked by the metal wiring 325. In the configuration according to the present embodiment, a transparent electrode 326 is provided on the third surface 305 side of the photoelectric conversion region 321 instead of the metal wiring 325, and a voltage VL2 is applied to the photoelectric conversion region 321 via the transparent electrode 326. By using the transparent electrode 326, not only the component that is vertically incident on the photoelectric conversion region 321 from directly above the photoelectric conversion region 321, but also the light that is obliquely incident on the semiconductor substrate 300 can be photoelectrically converted. In other words, the effect of improving the sensitivity to light is obtained. In this case, in order to prevent a decrease in near-infrared sensitivity, it is desirable that the material constituting the transparent electrode 326 is a material that does not absorb near-infrared light as much as possible.

[0052] Unlike the metal wiring 325, the transparent electrode 326 transmits light, and therefore may be provided so as to overlap not only the outer edge of the pixel 101 but also the entire surface of the photoelectric conversion region 321. By increasing the junction area between the transparent electrode 326 and the photoelectric conversion region 321, the contact resistance can be reduced, and a sufficient voltage is applied to the charge photoelectrically converted in the photoelectric conversion region 321, which is expected to improve the response speed of the photoelectric conversion device to light.

[0053] Furthermore, in the photoelectric conversion device according to this embodiment, the semiconductor substrate 300 has a charge collection region 317. The charge collection region 317 is a semiconductor region having a first conductivity type impurity concentration lower than that of the first semiconductor region 311. By providing the charge collection region 317 between the light incident surface side of the semiconductor substrate 300 and the second semiconductor region 312, a potential gradient can be formed from the light incident surface of the semiconductor substrate 300 to the avalanche region, and an effect of promoting charge transfer can be obtained.

[0054] Furthermore, in the photoelectric conversion device according to this embodiment, the columnar structure 322 of the third material extends from the first surface 303 into the semiconductor substrate 300. Since the third material constituting the columnar structure 322 has a higher mobility of signal charges than the first material, the photoelectrically converted charges move through the columnar structure 322. The charges that have moved through the columnar structure 322 can reach the avalanche multiplication region faster than the charges that have moved through the first material. As a result, the response speed until the charges are detected as a signal can be improved.

[0055] (Fourth embodiment) A photoelectric conversion device according to the fourth embodiment will be described with reference to Fig. 10. Descriptions common to the photoelectric conversion devices according to the first to third embodiments will be omitted, and differences from the photoelectric conversion device according to the first embodiment will be mainly described.

[0056] FIG. 10 is a cross-sectional view of two pixels of a photoelectric conversion device according to the fourth embodiment. This differs from FIG. 8 in that the photoelectric conversion region 321 of the second material is not provided separately for each pixel, but is arranged in a common photoelectric conversion region 321 for a plurality of pixels. For example, the photoelectric conversion region 321 may be arranged separately for a predetermined number of pixels, such as every four pixels, or one photoelectric conversion region 321 may be arranged over the entire surface of the pixel region 12. By increasing the area of ​​the photoelectric conversion region 321, the sensitivity to incident light can be improved. In addition, in the photoelectric conversion device according to this embodiment, the semiconductor substrate 300 has a charge collection region 317 as in the third embodiment.

[0057] On the other hand, the charge photoelectrically converted in the photoelectric conversion region 321 needs to be moved into the semiconductor substrate 300 via the columnar structure 322. In order to uniformly supply a potential to the columnar structure 322 from the periphery as in the second embodiment, an anode contact 324 is disposed at the boundary between the pixels 101 on the third surface 305 side of the photoelectric conversion layer 301 in FIG. 10. The pixel boundary is the position where the separation trench 316 is extended in a cross-sectional view. An anode voltage VL2 is applied from the metal wiring 325 to the photoelectric conversion region 321 via the anode contact 324. This allows a uniform lateral electric field to be applied to the charge photoelectrically converted in the photoelectric conversion region 321, preventing variation in charge transfer time due to bias in the electric field. In addition, a sufficient voltage is applied to the charge to induce it to the avalanche multiplication region, so that the response speed until the charge is detected as a signal can be maintained equivalent to that of the second embodiment.

[0058] Fifth embodiment A photoelectric conversion device according to the fifth embodiment will be described with reference to Fig. 11. Descriptions common to the photoelectric conversion devices according to the first to fourth embodiments will be omitted, and differences from the photoelectric conversion device according to the first embodiment will be mainly described.

[0059] Fig. 11 is a cross-sectional view of two pixels of a photoelectric conversion device according to a fifth embodiment. In the photoelectric conversion device shown in Fig. 11, a metal material is embedded in an isolation trench 316 that separates pixels 101 from each other. The isolation trench 316 penetrates the semiconductor substrate 300, and the embedded metal material is joined to the first surface 303 side of the photoelectric conversion region 321 via the sixth semiconductor region 323. An anode voltage VL is applied to the photoelectric conversion region 321.

[0060] By embedding a metal material in the isolation trench 316 disposed at the pixel boundary, it is possible to prevent crosstalk, in which incident light or avalanche light emission caused by recombination of electrons and holes in the avalanche multiplication region is incident on the photoelectric conversion layer 301 of an adjacent pixel. Furthermore, by increasing the junction area between the metal member embedded in the isolation trench 316 and the sixth semiconductor region, the metal member acts as a reflector for light incident from the third surface 305. As a result, light incident on the boundary of the pixel 101, which is the dead region of the photoelectric conversion layer 301, is also reflected and incident on the photoelectric conversion region 321, enabling photoelectric conversion, thereby improving the probability of detection (PDE) of the lattice per pixel.

[0061] Furthermore, in the photoelectric conversion device shown in Fig. 11, the areas of the first semiconductor region 311 and the second semiconductor region 312 that form the avalanche multiplication region are larger than those in the configuration of Fig. 7. This makes it possible to improve the response speed and time variability from when the charge photoelectrically converted in the semiconductor substrate 300 reaches the avalanche multiplication region and is detected as a signal.

[0062] Sixth embodiment A photoelectric conversion device according to the sixth embodiment will be described with reference to Fig. 12. Descriptions common to the photoelectric conversion devices according to the first to fifth embodiments will be omitted, and differences from the photoelectric conversion device according to the fourth embodiment will be mainly described.

[0063] 12 is a cross-sectional view of two pixels of a photoelectric conversion device according to the sixth embodiment. The metal material embedded in the isolation trench 316 is joined to the third surface 305 side of the photoelectric conversion region 321 via the sixth semiconductor region 323, and supplies an anode potential VL to the photoelectric conversion region 321. When light is incident on the photoelectric conversion region 321 from the third surface 305, the metal material functions as a light-shielding film to prevent the light from entering regions other than the photoelectric conversion region 321, thereby preventing the occurrence of optical crosstalk.

[0064] 12 has a charge collecting region 317 in the semiconductor substrate 300. The configuration of the avalanche diode is not limited to this, and it may have a wide avalanche multiplication region as shown in FIG.

[0065] Furthermore, the photoelectric conversion layer 301 has a first scattering diffraction structure 327 on the third surface 305 side. The first scattering diffraction structure 327 is, for example, a trench formed in a lattice shape. Light incident on the photoelectric conversion region 321 is diffracted and scattered by the first scattering diffraction structure 327. This increases the propagation distance of the light, and improves the quantum efficiency. In addition, since the photoelectric conversion layer 301 is surrounded by a metal material extending from the separation trench 316 for each pixel, the light scattered by the first scattering diffraction structure 327 is reflected by the metal material and propagates through the photoelectric conversion region 321 multiple times. In other words, a further improvement in quantum efficiency can be expected. The separation trench 316 also prevents crosstalk to adjacent pixels of avalanche light emission caused by recombination of electrons and holes in the avalanche multiplication region.

[0066] Seventh embodiment A photoelectric conversion device according to the seventh embodiment will be described with reference to Fig. 13 and Fig. 14. Descriptions common to the photoelectric conversion devices according to the first to sixth embodiments will be omitted, and differences from the photoelectric conversion device according to the sixth embodiment will be mainly described.

[0067] Fig. 13 is a plan view of two pixels of a photoelectric conversion device according to the seventh embodiment, and Fig. 14 is a cross-sectional view taken along the line AA' in Fig. 13. The photoelectric conversion device according to this embodiment has a plurality of columnar structures 322 per pixel 101. Charges photoelectrically converted in the photoelectric conversion region 321 reach the avalanche multiplication region via the columnar structure 322 close to the position where the photoelectric conversion occurs, and are avalanche multiplied. This improves the response speed to incident light, and improves the variation in the time it takes for the generated charges to be detected as a signal.

[0068] 12, the photoelectric conversion device according to this embodiment has a second scattering diffraction structure 328 on the first surface 303 of the semiconductor substrate 300 in addition to the first scattering diffraction structure 327 provided on the third surface 305 side of the photoelectric conversion layer 301. The second scattering diffraction structure 328 is a trench structure formed in a lattice shape as shown in FIG. 13, for example. The second scattering diffraction structure 328 does not overlap with each of the columnar structures 322 on a vertical line in a cross-sectional view or a planar view. The incident light that is not diffracted by the first scattering diffraction structure 327 and is not photoelectrically converted in the photoelectric conversion region 321 and travels straight to reach the semiconductor substrate 300 among the light incident from the third surface 305 can be diffracted by the second scattering diffraction structure 328 and photoelectrically converted in the semiconductor substrate 300. Therefore, the quantum efficiency can be improved by providing the second scattering diffraction structure 328.

[0069] Eighth embodiment A photoelectric conversion device according to the eighth embodiment will be described with reference to Fig. 15. Descriptions common to the photoelectric conversion devices according to the first to seventh embodiments will be omitted, and differences from the photoelectric conversion device according to the first embodiment will be mainly described.

[0070] Fig. 15 is a cross-sectional view of a pixel according to the eighth embodiment. Fig. 15 differs from Fig. 8 in that a photoelectric conversion layer 301 including a photoelectric conversion region 321 is formed on the side of the surface of the semiconductor substrate 300 facing the first surface 303.

[0071] The photoelectric conversion device shown in FIG. 15 has a structure in which a semiconductor substrate 300 and a wiring layer 302 including a photoelectric conversion layer 301 are laminated in a cross-sectional view. The semiconductor substrate 300 is made of a first material and has a first surface 303 and a second surface 304. A pinning film 320 and a planarization film 329 are formed on the first surface 303, forming a third surface 305 that is a light incidence surface. The second surface 304 of the semiconductor substrate 300 is laminated so as to face a seventh surface 307 of the wiring layer 302. The wiring layer 302 has a fourth surface 306 that faces the seventh surface 307. A photoelectric conversion region 321 made of a second material and having an eighth surface 308 and a ninth surface 309 is provided in the wiring layer 302. The photoelectric conversion region 321 has a through hole penetrating from the eighth surface 308 to the ninth surface 309, and a through electrode penetrating the through hole and an insulating film covering the inside of the through hole are provided. Further, a sixth semiconductor region 323 of the second material is provided on the ninth face 309 of the photoelectric conversion region 321 .

[0072] A first semiconductor region 311 of a first conductivity type is provided on the second surface 304 side in the semiconductor substrate 300, and a third semiconductor region 313 of a first conductivity type and a second semiconductor region 312 of a second conductivity type are provided on the first surface 303 side of the first semiconductor region 311. The third semiconductor region 313 has a lower impurity concentration of the first conductivity type than the first semiconductor region 311. The semiconductor substrate 300 further has a fourth semiconductor region 314 of a second conductivity type and a fifth semiconductor region 315 of a second conductivity type, and the second semiconductor region 312 is in contact with the fourth semiconductor region 314. The semiconductor substrate 300 also has a charge collecting region 317 and a second scattering diffraction structure 328. The function of each member is the same as that of the member having the same name in the description of each embodiment.

[0073] A voltage VH (first voltage) is applied to the first conductivity type first semiconductor region 311. Meanwhile, a voltage VL (second voltage) is supplied to the second conductivity type fifth semiconductor region 315, and the voltage VL is also applied to the second conductivity type second semiconductor region 312 through the second conductivity type fourth semiconductor region 314. An avalanche multiplication region is formed in a region where the first conductivity type first semiconductor region 311 and the second conductivity type second semiconductor region 312 are adjacent to each other.

[0074] In the photoelectric conversion device according to this embodiment, light incident from the third surface 305 is diffracted by the second scattering diffraction structure 328 provided on the first surface 303 of the semiconductor substrate 300, and a part of the light is photoelectrically converted in the semiconductor substrate 300. Of the incident light, a component in the near-infrared wavelength band propagates into the wiring layer 302 and is photoelectrically converted in the photoelectric conversion region 321. The charge photoelectrically converted in the photoelectric conversion region 321 moves to the semiconductor substrate 300 via the columnar structure 322, is collected in the charge collection region 317, is multiplied in the avalanche multiplication region, and is counted as a signal.

[0075] In the photoelectric conversion device according to this embodiment, the photoelectric conversion layer 301 can be formed before forming the wiring layer 302. By annealing the photoelectric conversion layer 301 at a high temperature before forming the wiring layer 302, recovery of defects in the photoelectric conversion layer 301 can be promoted and noise can be reduced.

[0076] Ninth embodiment The photoelectric conversion system according to this embodiment will be described with reference to Fig. 16. Fig. 16 is a block diagram showing a schematic configuration of the photoelectric conversion system according to this embodiment.

[0077] The photoelectric conversion devices described in the first to eighth embodiments are applicable to various photoelectric conversion systems. Examples of the applicable photoelectric conversion systems include digital still cameras, digital camcorders, security cameras, copiers, fax machines, mobile phones, car-mounted cameras, and observation satellites. Camera modules equipped with an optical system such as a lens and an imaging device are also included in the photoelectric conversion systems. FIG. 16 illustrates a block diagram of a digital still camera as an example of these.

[0078] 16 includes an image pickup device 1004, which is an example of a photoelectric conversion device, and a lens 1002 that forms an optical image of a subject on the image pickup device 1004. The system further includes an aperture 1003 that varies the amount of light passing through the lens 1002, and a barrier 1001 that protects the lens 1002. The lens 1002 and the aperture 1003 form an optical system that focuses light on the image pickup device 1004. The image pickup device 1004 is a photoelectric conversion device according to any one of the above embodiments, and converts the optical image formed by the lens 1002 into an electrical signal.

[0079] The photoelectric conversion system also has a signal processing unit 1007 which is an image generating unit that generates an image by processing an output signal output from the imaging device 1004. The signal processing unit 1007 performs various corrections and compression as necessary to output image data. The signal processing unit 1007 may be formed on the semiconductor substrate on which the imaging device 1004 is provided, or may be formed on a semiconductor substrate separate from the imaging device 1004.

[0080] The photoelectric conversion system further includes a memory unit 1010 for temporarily storing image data, and an external interface unit (external I / F unit) 1013 for communicating with an external computer or the like. The photoelectric conversion system further includes a recording medium 1012 such as a semiconductor memory for recording or reading out imaging data, and a recording medium control interface unit (recording medium control I / F unit) 1011 for recording or reading out data on the recording medium 1012. The recording medium 1012 may be built into the photoelectric conversion system, or may be removable.

[0081] The photoelectric conversion system further includes an overall control / calculation unit 1009 that performs various calculations and controls the entire digital still camera, and a timing generation unit 1008 that outputs various timing signals to the image capture device 1004 and the signal processing unit 1007. Here, the timing signals and the like may be input from outside, and the photoelectric conversion system only needs to include at least the image capture device 1004 and the signal processing unit 1007 that processes the output signal output from the image capture device 1004.

[0082] The imaging device 1004 outputs an imaging signal to a signal processing unit 1007. The signal processing unit 1007 performs predetermined signal processing on the imaging signal output from the imaging device 1004, and outputs image data. The signal processing unit 1007 generates an image using the imaging signal.

[0083] In this way, according to this embodiment, it is possible to realize a photoelectric conversion system to which the photoelectric conversion device (imaging device) according to any one of the above embodiments is applied.

[0084] (Tenth embodiment) The photoelectric conversion system and the moving object of this embodiment will be described with reference to Fig. 17. Fig. 17 is a diagram showing the configuration of the photoelectric conversion system and the moving object of this embodiment.

[0085] FIG. 17(a) shows an example of a photoelectric conversion system related to an in-vehicle camera. The photoelectric conversion system 1300 has an imaging device 1310. The imaging device 1310 is the photoelectric conversion device described in any of the above embodiments. The photoelectric conversion system 1300 has an image processing unit 1312 that performs image processing on a plurality of image data acquired by the imaging device 1310, and a parallax acquisition unit 1314 that calculates parallax (phase difference of parallax images) from the plurality of image data acquired by the photoelectric conversion system 1300. The photoelectric conversion system 1300 also has a distance acquisition unit 1316 that calculates a distance to an object based on the calculated parallax, and a collision determination unit 1318 that determines whether or not there is a possibility of collision based on the calculated distance. Here, the parallax acquisition unit 1314 and the distance acquisition unit 1316 are examples of distance information acquisition means that acquire distance information to an object. That is, the distance information is information on the parallax, the defocus amount, the distance to the object, and the like. The collision determination unit 1318 may determine the possibility of a collision using any of these distance information. The distance information acquisition means may be realized by dedicated hardware or a software module. Also, it may be realized by an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like, or may be realized by a combination of these. The photoelectric conversion system 1300 is connected to a vehicle information acquisition device 1320, and can acquire vehicle information such as vehicle speed, yaw rate, and steering angle. In addition, the photoelectric conversion system 1300 is connected to a control ECU 1330, which is a control unit that outputs a control signal for generating a braking force for the vehicle based on the determination result of the collision determination unit 1318. In addition, the photoelectric conversion system 1300 is also connected to an alarm device 1340 that issues an alarm to the driver based on the determination result of the collision determination unit 1318. For example, if the collision determination unit 1318 determines that there is a high possibility of a collision, the control ECU 1330 applies the brakes, releases the accelerator, suppresses engine output, or performs other vehicle control to avoid a collision and reduce damage.The alarm device 1340 warns the user by sounding an alarm, displaying alarm information on the screen of a car navigation system or the like, vibrating the seat belt or steering wheel, or the like.

[0086] In this embodiment, the surroundings of the vehicle, for example, the front or rear, are imaged by the photoelectric conversion system 1300. Fig. 17(b) shows a photoelectric conversion system for imaging the area in front of the vehicle (imaging range 1350). A vehicle information acquisition device 1320 sends instructions to the photoelectric conversion system 1300 or the imaging device 1310. This configuration can further improve the accuracy of distance measurement.

[0087] Although the above describes an example of control to prevent collision with other vehicles, the present invention can also be applied to control of automatic driving by following other vehicles, control of automatic driving to prevent deviation from lanes, etc. Furthermore, the photoelectric conversion system is not limited to vehicles such as the vehicle itself, but can be applied to moving bodies (moving devices) such as ships, aircraft, and industrial robots. In addition, the present invention can be applied not only to moving bodies, but also to a wide range of devices that use object recognition, such as intelligent transport systems (ITS).

[0088] (Eleventh embodiment) The photoelectric conversion system of this embodiment will be described with reference to Fig. 18. Fig. 18 is a block diagram showing an example of the configuration of a range image sensor which is the photoelectric conversion system of this embodiment.

[0089] 18, the distance image sensor 401 is configured to include an optical system 407, a photoelectric conversion device 408, an image processing circuit 404, a monitor 405, and a memory 406. The distance image sensor 401 can obtain a distance image according to the distance to the subject by receiving light (modulated light or pulsed light) that is projected from a light source device 409 toward the subject and reflected from the surface of the subject.

[0090] The optical system 407 is configured to have one or more lenses, and guides image light (incident light) from a subject to a photoelectric conversion device 408 , forming an image on the light receiving surface (sensor portion) of the photoelectric conversion device 408 .

[0091] As the photoelectric conversion device 408 , the photoelectric conversion device of each of the above-mentioned embodiments is applied, and a distance signal indicating a distance determined from a light reception signal output from the photoelectric conversion device 408 is supplied to the image processing circuit 404 .

[0092] The image processing circuit 404 performs image processing to construct a distance image based on the distance signal supplied from the photoelectric conversion device 408. The distance image (image data) obtained by this image processing is then supplied to a monitor 405 for display, or supplied to a memory 406 for storage (recording).

[0093] In the range image sensor 401 configured in this way, by applying the above-described photoelectric conversion device, it is possible to obtain, for example, a more accurate range image as the pixel characteristics improve.

[0094] (Twelfth embodiment) The photoelectric conversion system of this embodiment will be described with reference to Fig. 19. Fig. 19 is a diagram showing an example of a schematic configuration of an endoscopic surgery system which is the photoelectric conversion system of this embodiment.

[0095] 19 shows a state in which an operator (doctor) 1131 is performing surgery on a patient 1132 on a patient bed 1133 using an endoscopic surgery system 1150. As shown in the figure, the endoscopic surgery system 1150 is composed of an endoscope 1100, a surgical tool 1110, and a cart 1134 on which various devices for endoscopic surgery are mounted.

[0096] The endoscope 1100 is composed of a lens barrel 1101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 1132, and a camera head 1102 connected to the base end of the lens barrel 1101. In the illustrated example, the endoscope 1100 is configured as a so-called rigid lens barrel having a rigid lens barrel 1101, but the endoscope 1100 may be configured as a so-called flexible lens barrel having a flexible lens barrel.

[0097] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 1101. A light source device 1203 is connected to the endoscope 1100, and light generated by the light source device 1203 is guided to the tip of the lens barrel 1101 by a light guide extending inside the lens barrel 1101, and is irradiated via the objective lens toward an observation target in a body cavity of a patient 1132. The endoscope 1100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0098] An optical system and a photoelectric conversion device are provided inside the camera head 1102, and reflected light (observation light) from an observation target is collected by the optical system onto the photoelectric conversion device. The observation light is photoelectrically converted by the photoelectric conversion device to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to an observation image. The photoelectric conversion device described in each of the above-mentioned embodiments can be used as the photoelectric conversion device. The image signal is transmitted to a camera control unit (CCU) 1135 as RAW data.

[0099] The CCU 1135 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and performs overall control of the operations of the endoscope 1100 and the display device 1136. Furthermore, the CCU 1135 receives an image signal from the camera head 1102, and performs various types of image processing on the image signal, such as development processing (demosaic processing), for displaying an image based on the image signal.

[0100] Under the control of the CCU 1135 , the display device 1136 displays an image based on an image signal that has been subjected to image processing by the CCU 1135 .

[0101] The light source device 1203 is composed of a light source such as an LED (Light Emitting Diode), and supplies the endoscope 1100 with irradiation light when photographing an operation site or the like.

[0102] The input device 1137 is an input interface for the endoscopic surgery system 1150. A user can input various information and instructions to the endoscopic surgery system 1150 via the input device 1137.

[0103] The treatment tool control device 1138 controls the driving of the energy treatment tool 1112 for cauterizing tissue, incising, sealing blood vessels, or the like.

[0104] The light source device 1203 that supplies irradiation light to the endoscope 1100 when photographing the surgical site can be composed of a white light source composed of, for example, an LED, a laser light source, or a combination of these. When the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so that the white balance of the captured image can be adjusted in the light source device 1203. In this case, it is also possible to capture images corresponding to each of the RGB colors in a time-division manner by irradiating the observation target with laser light from each of the RGB laser light sources in a time-division manner and controlling the driving of the image sensor of the camera head 1102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter to the image sensor.

[0105] Furthermore, the light source device 1203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. By controlling the driving of the image sensor of the camera head 1102 in synchronization with the timing of the change in the light intensity to acquire images in a time-division manner and synthesizing the images, it is possible to generate an image with a high dynamic range that is free of so-called blocked-up shadows and blown-out highlights.

[0106] The light source device 1203 may be configured to supply light in a predetermined wavelength band corresponding to the special light observation. In the special light observation, for example, the wavelength dependency of light absorption in body tissue is utilized. Specifically, a predetermined tissue such as blood vessels on the mucous membrane surface is photographed with high contrast by irradiating light in a narrower band than the irradiation light (i.e., white light) in normal observation. Alternatively, the special light observation may be a fluorescent observation in which an image is obtained by fluorescence generated by irradiating excitation light. In the fluorescent observation, it is possible to irradiate excitation light to the body tissue and observe the fluorescence from the body tissue, or to locally inject a reagent such as indocyanine green (ICG) into the body tissue and irradiate the body tissue with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 1203 may be configured to supply narrow band light and / or excitation light corresponding to such special light observation.

[0107] Thirteenth embodiment The photoelectric conversion system of this embodiment will be described with reference to Figs. 20(a) and (b). Fig. 20(a) describes glasses 1600 (smart glasses) which are the photoelectric conversion system of this embodiment. The glasses 1600 have a photoelectric conversion device 1602. The photoelectric conversion device 1602 is the photoelectric conversion device described in each of the above embodiments. A display device including a light-emitting device such as an OLED or LED may be provided on the back side of the lens 1601. The photoelectric conversion device 1602 may be one or more. A combination of multiple types of photoelectric conversion devices may also be used. The arrangement position of the photoelectric conversion device 1602 is not limited to that shown in Fig. 20(a).

[0108] The glasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the photoelectric conversion device 1602 and the display device. The control device 1603 also controls the operations of the photoelectric conversion device 1602 and the display device. The lens 1601 is formed with an optical system for focusing light on the photoelectric conversion device 1602.

[0109] FIG. 20(b) illustrates glasses 1610 (smart glasses) according to one application example. The glasses 1610 have a control device 1612, and the control device 1612 is equipped with a photoelectric conversion device corresponding to the photoelectric conversion device 1602 and a display device. The lens 1611 is formed with an optical system for projecting light emitted from the photoelectric conversion device in the control device 1612 and the display device, and an image is projected onto the lens 1611. The control device 1612 functions as a power source for supplying power to the photoelectric conversion device and the display device, and controls the operation of the photoelectric conversion device and the display device. The control device may have a line of sight detection unit that detects the line of sight of the wearer. Infrared light may be used for detecting the line of sight. The infrared light emission unit emits infrared light toward the eyeball of a user gazing at a display image. An imaging unit having a light receiving element detects the reflected light of the emitted infrared light from the eyeball, thereby obtaining an image of the eyeball. By having a reduction means for reducing light from the infrared light emission unit to the display unit in a planar view, deterioration of image quality is reduced.

[0110] The gaze of the user with respect to the displayed image is detected from an image of the eyeball obtained by capturing infrared light. Any known method can be applied to gaze detection using the image of the eyeball. As an example, a gaze detection method based on a Purkinje image formed by reflection of irradiated light on the cornea can be used.

[0111] More specifically, the gaze detection process is performed based on the pupil-corneal reflex method. Using the pupil-corneal reflex method, a gaze vector that indicates the direction (rotation angle) of the eyeball is calculated based on the pupil image and the Purkinje image included in the captured image of the eyeball, thereby detecting the user's gaze.

[0112] The display device of this embodiment may have a photoelectric conversion device having a light receiving element, and may control the display image of the display device based on information about the user's line of sight from the photoelectric conversion device.

[0113] Specifically, the display device determines a first field of view area to which the user gazes and a second field of view area other than the first field of view area based on the line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be received from an external control device. In the display area of ​​the display device, the display resolution of the first field of view area may be controlled to be higher than the display resolution of the second field of view area. In other words, the resolution of the second field of view area may be lower than that of the first field of view area.

[0114] The display area may have a first display area and a second display area different from the first display area, and a high priority area may be determined from the first display area and the second display area based on line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be determined by an external control device and received. The resolution of the high priority area may be controlled to be higher than the resolution of areas other than the high priority area. In other words, the resolution of an area with a relatively low priority may be lowered.

[0115] AI may be used to determine the first field of view area and areas with high priority. The AI ​​may be a model configured to estimate the angle of the line of sight and the distance to an object at the end of the line of sight from the image of the eyeball, using as teacher data an image of the eyeball and the direction in which the eyeball in the image was actually looking. The AI ​​program may be included in the display device, the photoelectric conversion device, or an external device. If included in the external device, it is transmitted to the display device via communication.

[0116] When display control is performed based on visual recognition detection, the present invention is preferably applicable to smart glasses further including a photoelectric conversion device for capturing an image of the outside world. The smart glasses can display captured outside information in real time.

[0117] [Modified embodiment] The present invention is not limited to the above-described embodiment, and various modifications are possible.

[0118] For example, an example in which part of the configuration of any one of the embodiments is added to another embodiment, or an example in which part of the configuration of another embodiment is substituted therefor, is also included in the embodiments of the present invention.

[0119] Further, the photoelectric conversion systems shown in the fifth and sixth embodiments are examples of photoelectric conversion systems to which the photoelectric conversion device can be applied, and the photoelectric conversion systems to which the photoelectric conversion device of the present invention can be applied are not limited to the configurations shown in Fig. 15 to Fig. 19. The same applies to the ToF system shown in the seventh embodiment, the endoscope shown in the eighth embodiment, and the smart glasses shown in the ninth embodiment.

[0120] It should be noted that the above-mentioned embodiments are merely examples of the implementation of the present invention, and the technical scope of the present invention should not be interpreted as being limited by these embodiments. In other words, the present invention can be implemented in various forms without departing from its technical concept or main features.

[0121] The present disclosure has the following configuration.

[0122] (Configuration 1) The photoelectric conversion device includes a semiconductor substrate made of a first material and having an avalanche photodiode, and a photoelectric conversion layer made of a second material having a band gap smaller than that of the first material. The device further includes a region in contact with the semiconductor substrate and the photoelectric conversion layer and made of a third material containing at least an element of the first material or the second material. When viewed from above, the area of ​​the region is smaller than that of the photoelectric conversion layer.

[0123] (Configuration 2) 2. The photoelectric conversion device according to configuration 1, wherein the third material and the first material are the same.

[0124] (Configuration 3) 2. The photoelectric conversion device according to configuration 1, wherein the third material and the second material are the same.

[0125] (Configuration 4) 4. The photoelectric conversion device according to any one of configurations 1 to 3, wherein the first material is silicon, and the second material contains germanium.

[0126] (Configuration 5) 5. The photoelectric conversion device according to configuration 4, wherein the second material is germanium.

[0127] (Configuration 6) 4. The photoelectric conversion device according to any one of configurations 1 to 3, wherein the first material is silicon, and the second material is indium gallium arsenide.

[0128] (Configuration 7) 7. The photoelectric conversion device according to any one of configurations 1 to 6, wherein, in top view, the region overlaps with an avalanche multiplication region of the avalanche photodiode.

[0129] (Configuration 8) The avalanche photodiode has a first semiconductor region of a first conductivity type and a second semiconductor region of a second conductivity type, and the photoelectric conversion layer has a third semiconductor region. The photoelectric conversion device according to any one of configurations 1 to 7, wherein a voltage is applied to each of the first semiconductor region, the second semiconductor region, and the third semiconductor region.

[0130] (Configuration 9) 9. The photoelectric conversion device according to configuration 8, wherein a transparent electrode is disposed so as to overlap the third semiconductor region when viewed from above.

[0131] (Configuration 10) 10. The photoelectric conversion device according to any one of configurations 1 to 9, wherein the region extends into the semiconductor substrate from a surface of the semiconductor substrate facing the photoelectric conversion layer.

[0132] (Configuration 11) The photoelectric conversion device according to any one of configurations 1 to 10, comprising a first avalanche photodiode and a second avalanche photodiode, and a separation section is provided between the first avalanche photodiode and the second avalanche photodiode, and a contact for supplying a voltage to the first avalanche photodiode is disposed directly above the separation section.

[0133] (Configuration 12) The photoelectric conversion device according to any one of configurations 1 to 11, comprising a first pixel having a first avalanche photodiode and a first photoelectric conversion layer, and a second pixel having a second avalanche photodiode and a second photoelectric conversion layer, which are provided adjacent to each other, and a light-shielding portion formed between the first pixel and the second pixel is in contact with a lower portion of the first photoelectric conversion layer and supplies a potential thereto.

[0134] (Configuration 13) The photoelectric conversion device according to any one of configurations 1 to 12, comprising a first pixel having a first avalanche photodiode and a first photoelectric conversion layer, and a second pixel having a second avalanche photodiode and a second photoelectric conversion layer, which are provided adjacent to each other, and a light-shielding portion formed between the first pixel and the second pixel is in contact with an upper portion of the first photoelectric conversion layer and supplies a potential thereto.

[0135] (Configuration 14) 14. The photoelectric conversion device according to any one of configurations 1 to 13, wherein, in a cross-sectional view, the thickness of the semiconductor substrate is smaller than the thickness of the photoelectric conversion layer.

[0136] (Configuration 15) 15. The photoelectric conversion device according to claim 1, wherein a pinning film is formed in a location other than a junction between the semiconductor substrate and the region.

[0137] (Configuration 16) 16. The photoelectric conversion device according to any one of configurations 1 to 15, further comprising a scattering / diffractive structure on the light incident surface of the semiconductor substrate.

[0138] (Configuration 17) 17. The photoelectric conversion device according to any one of configurations 1 to 16, wherein the region has a scattering diffraction structure.

[0139] (Configuration 18) 18. The photoelectric conversion device according to any one of configurations 1 to 17, wherein one of the photoelectric conversion layers has a plurality of the regions.

[0140] (Configuration 19) A photoelectric conversion device according to any one of configurations 1 to 18, characterized in that a wiring layer is provided by being stacked on the semiconductor substrate, and the photoelectric conversion layer is formed on the side of the semiconductor substrate on which the wiring layer is stacked.

[0141] (Configuration 20) A photoelectric conversion device described in any one of configurations 1 to 18, characterized in that a wiring layer is provided by being stacked on the semiconductor substrate, and the photoelectric conversion layer is formed on the side of the semiconductor substrate opposite to the side on which the wiring layer is stacked.

[0142] (Configuration 21) 21. A photoelectric conversion system comprising: the photoelectric conversion device according to any one of configurations 1 to 20; and a signal processing unit that generates an image using a signal output from the photoelectric conversion device.

[0143] (Configuration 22) 21. A moving body comprising the photoelectric conversion device according to any one of configurations 1 to 20, and a control unit that controls the movement of the moving body using a signal output from the photoelectric conversion device. [Explanation of symbols]

[0144] 300 Semiconductor Substrate 301 Photoelectric conversion layer 322 Columnar structure

Claims

1. A semiconductor substrate comprising a first material and having an avalanche photodiode, The device comprises a photoelectric conversion layer composed of a second material having a smaller band gap than the first material, The semiconductor substrate and the photoelectric conversion layer have a region that is in contact with the semiconductor substrate and is composed of a third material containing at least the elements of the first material or the second material, A photoelectric conversion device characterized in that, in a top view, the region is surrounded by an insulating material, and the area of ​​the region is smaller than the area of ​​the photoelectric conversion layer.

2. The photoelectric conversion device according to claim 1, characterized in that the third material and the first material are the same.

3. The photoelectric conversion device according to claim 1, characterized in that the third material and the second material are the same.

4. The photoelectric conversion device according to claim 1, characterized in that the first material is silicon and the second material contains germanium.

5. The photoelectric conversion device according to claim 4, characterized in that the second material is germanium.

6. The photoelectric conversion device according to claim 1, characterized in that the first material is silicon and the second material is indium gallium arsenide.

7. The photoelectric conversion device according to claim 1, characterized in that, in a top view, the region overlaps with the avalanche multiplication region of the avalanche photodiode.

8. The avalanche photodiode has a first semiconductor region of a first conductivity type and a second semiconductor region of a second conductivity type. The photoelectric conversion layer has a third semiconductor region, The photoelectric conversion device according to claim 1, characterized in that a voltage is applied to each of the first semiconductor region, the second semiconductor region, and the third semiconductor region.

9. The photoelectric conversion apparatus according to claim 8, characterized in that, in a top view, a transparent electrode is arranged overlapping the third semiconductor region.

10. The photoelectric conversion apparatus according to claim 1, characterized in that the region extends into the semiconductor substrate from the surface of the semiconductor substrate facing the photoelectric conversion layer.

11. It comprises a first avalanche photodiode and a second avalanche photodiode, A separation section is provided between the first avalanche photodiode and the second avalanche photodiode. The photoelectric conversion device according to claim 1, characterized in that a contact for supplying voltage to the first avalanche photodiode is arranged directly above the separation portion.

12. A first pixel having a first avalanche photodiode and a first photoelectric conversion layer, A second pixel having a second avalanche photodiode and a second photoelectric conversion layer is provided adjacent to each other. The light-shielding portion formed between the first pixel and the second pixel is The photoelectric conversion device according to claim 1, characterized in that it contacts the lower part of the first photoelectric conversion layer and supplies an electric potential.

13. A first pixel having a first avalanche photodiode and a first photoelectric conversion layer, A second pixel having a second avalanche photodiode and a second photoelectric conversion layer is provided adjacent to each other. The light-shielding portion formed between the first pixel and the second pixel is The photoelectric conversion device according to claim 1, characterized in that it contacts the upper part of the first photoelectric conversion layer and supplies an electric potential.

14. The photoelectric conversion apparatus according to claim 1, characterized in that, in a cross-sectional view, the thickness of the semiconductor substrate is smaller than the thickness of the photoelectric conversion layer.

15. The photoelectric conversion apparatus according to claim 1, characterized in that a pinning film is formed at a location other than the junction between the semiconductor substrate and the region.

16. The photoelectric conversion device according to claim 1, characterized in that the light incident surface of the semiconductor substrate is provided with a scattering diffraction structure.

17. The photoelectric conversion device according to claim 1, characterized in that it comprises a scattering diffraction structure in the aforementioned region.

18. The photoelectric conversion apparatus according to claim 1, characterized in that it has a plurality of regions with respect to one of the photoelectric conversion layers.

19. A wiring layer is provided on the semiconductor substrate, The photoelectric conversion device according to claim 1, characterized in that the photoelectric conversion layer is formed on the side of the semiconductor substrate on which the wiring layers are stacked.

20. A wiring layer is provided on the semiconductor substrate, The photoelectric conversion device according to claim 1, characterized in that the photoelectric conversion layer is formed on the side of the semiconductor substrate opposite to the surface on which the wiring layers are stacked.

21. A photoelectric conversion device according to any one of claims 1 to 20, A photoelectric conversion system characterized by having a signal processing unit that generates an image using the signal output by the aforementioned photoelectric conversion device.

22. A mobile body comprising a photoelectric converter according to any one of claims 1 to 20, A mobile body characterized by having a control unit that controls the movement of the mobile body using a signal output by the photoelectric converter.

Images