Photoelectric converter, photoelectric converter system

Abstract

To provide a photoelectric conversion system that reduces optical color mixture in a photoelectric conversion device.SOLUTION: A photoelectric conversion device has a plurality of photoelectric conversion parts arranged in a semiconductor layer having a first surface and a second surface opposite to the first surface. The plurality of photoelectric conversion parts are separated from each other by a separation structure. The semiconductor layer includes a plurality of groove parts provided in the first surface of the photoelectric conversion part defined by the separation structure. The plurality of groove parts are composed of first groove parts extending in a first direction being an in-plane direction of the first surface, and second groove parts extending in a second direction being an in-plane direction of the first surface, the direction intersecting the first direction. Filling members and gaps are arranged in the groove parts at portions where the first groove parts and the second groove parts intersect each other.SELECTED DRAWING: Figure 6

Description

Technical Field

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

Background Art

[0002] There is a photoelectric conversion device that provides a concavo-convex structure on a light-receiving surface of a photoelectric conversion element to refract incident light, thereby increasing the optical path length of the incident light in the photoelectric conversion element and improving the quantum efficiency.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, there are problems that the increase amount of the optical path length is limited and the optical color mixing is large.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a photoelectric conversion device and a photoelectric conversion system with reduced optical color mixing.

Means for Solving the Problems

[0006] One aspect of the present invention is a photoelectric conversion device, comprising: The surface on which light is incident. a plurality of photoelectric conversion parts arranged in a semiconductor layer having a first surface and a second surface facing the first surface, each of the plurality of photoelectric conversion parts being separated by a separation structure, and the semiconductor layer having a plurality of groove parts provided on the first surface of the photoelectric conversion part defined by the separation structure a third semiconductor region in contact with the end of the second surface side of the plurality of grooves, and a sixth semiconductor region adjacent to the second surface side of the third semiconductor region,The plurality of grooves are comprised of a first groove extending in a first direction which is the in-plane direction of the first surface, and a second groove extending in a second direction which is the in-plane direction of the first surface and intersects the first direction. The conductivity types of the third semiconductor region and the sixth semiconductor region are opposite to each other, and the shortest distance from the first surface to the end of the plurality of grooves on the second surface side is shorter than the shortest distance from the first surface to the sixth semiconductor region. The invention is characterized in that a filling member and a void are arranged within the groove at the point where the first groove and the second groove intersect. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a photoelectric conversion system that reduces optical color mixing in a photoelectric conversion device. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a photoelectric conversion device according to an embodiment. [Figure 2] This is a schematic diagram of the PD substrate of the photoelectric converter according to the embodiment. [Figure 3] This is a schematic diagram of the circuit board of a photoelectric converter according to an embodiment. [Figure 4] This is an example of the configuration of a pixel circuit in a photoelectric conversion device according to an embodiment. [Figure 5] This is a schematic diagram showing the drive of the pixel circuit of a photoelectric converter according to an embodiment. [Figure 6] This is a cross-sectional view of a pixel of a photoelectric converter according to the first embodiment. [Figure 7] This is a plan view of the pixels of a photoelectric converter according to the first embodiment. [Figure 8] This is a schematic diagram of a photoelectric converter according to the first embodiment. [Figure 9] This is a schematic diagram of a photoelectric converter according to the first embodiment. [Figure 10] This is a schematic diagram of a photoelectric converter according to the first embodiment. [Figure 11] This is a schematic diagram of a photoelectric converter according to the second embodiment. [Figure 12] This is a schematic diagram of a photoelectric converter according to the third embodiment. [Figure 13]It is a functional block diagram of a photoelectric conversion system according to a fourth embodiment. [Figure 14] It is a functional block diagram of a photoelectric conversion system according to a fifth embodiment. [Figure 15] It is a functional block diagram of a photoelectric conversion system according to a sixth embodiment. [Figure 16] It is a functional block diagram of a photoelectric conversion system according to a seventh embodiment. [Figure 17] It is a functional block diagram of a photoelectric conversion system according to an eighth embodiment.

Embodiments for Carrying Out the Invention

[0009] The embodiments shown below are for embodying the technical idea of the present invention and do not limit the present invention. The sizes and positional relationships of the members shown in each drawing may be exaggerated for clarity of explanation. In the following description, the same components may be denoted by the same reference numerals and the description thereof may be omitted.

[0010] Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In the following description, terms indicating a specific direction or position (for example, "up", "down", "right", "left", and other terms including those terms) are used as necessary. The use of those terms is for facilitating the understanding of the embodiments with reference to the drawings, and the technical scope of the present invention is not limited by the meanings of those terms.

[0011] In this specification, a plan view means viewing from a direction perpendicular to the light incident surface of the semiconductor layer. Also, a cross-sectional view means a plane in a direction perpendicular to the light incident surface of the semiconductor layer. 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.

[0012] In the following description, the anode of an APD (avalanche photodiode) is set to a fixed potential, and a signal is taken out from the cathode side. Therefore, the first conductive type semiconductor region having majority carriers with the same polarity as the signal charge is an N-type semiconductor region, and the second conductive type semiconductor region having majority carriers with a polarity different from the signal charge is a P-type semiconductor region. Note that the present invention is also applicable 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 majority carriers with the same polarity as the signal charge is a P-type semiconductor region, and the second conductive type semiconductor region having majority carriers with a polarity different from the signal charge is an N-type semiconductor region. In the following, the case where one node of the APD is set to a fixed potential will be described, but the potentials of both nodes may vary.

[0013] In this specification, when the term "impurity concentration" is simply used, it means the net impurity concentration obtained by subtracting the amount compensated by the reverse conductive type impurity. That is, the "impurity concentration" refers to the NET doping concentration. A region where the P-type added impurity concentration is higher than the N-type added impurity concentration is a P-type semiconductor region. Conversely, a region where the N-type added impurity concentration is higher than the P-type added impurity concentration is an N-type semiconductor region.

[0014] Configurations common to each embodiment of the photoelectric conversion device and its driving method according to the present invention will be described with reference to FIGS. 1 to 5.

[0015] Figure 1 shows the configuration of a stacked photoelectric converter 100 according to an embodiment of the present invention. The photoelectric converter 100 is constructed by stacking two substrates, a sensor substrate 11 and a circuit board 21, and electrically connecting them. The sensor substrate 11 has a first semiconductor layer having a photoelectric conversion element 102 (described later) and a first wiring structure. The circuit board 21 has a second semiconductor layer having a circuit such as a signal processing unit 103 (described later) and a second wiring structure. The photoelectric converter 100 is constructed by stacking the second semiconductor layer, the second wiring structure, the first wiring structure, and the first semiconductor layer in that order. The photoelectric converter described in each embodiment is a back-illuminated type photoelectric converter in which light is incident from the first surface and the circuit board is arranged on the second surface.

[0016] In the following description, the sensor substrate 11 and the circuit board 21 are explained using diced chips, but they are not limited to chips. For example, each substrate may be a wafer. Furthermore, each substrate may be stacked in wafer form and then diced, or it may be made into chips and then stacked and bonded together.

[0017] The sensor board 11 is provided with a pixel region 12, and the circuit board 21 is provided with a circuit region 22 for processing signals detected in the pixel region 12.

[0018] Figure 2 shows an example of the arrangement of the sensor substrate 11. Pixels 101, each having a photoelectric conversion element 102 including an APD, are arranged in a two-dimensional array in a planar view, forming a pixel region 12.

[0019] Pixel 101 is typically a pixel used to form an image, but when used in TOF (Time of Flight), it does not necessarily have to form an image. In other words, pixel 101 may be a pixel used to measure the time and amount of light that arrives.

[0020] Figure 3 is a diagram of the circuit board 21. It includes a signal processing unit 103 for processing the charge photoelectrically converted by the photoelectric conversion element 102 in Figure 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.

[0021] The photoelectric conversion element 102 in Figure 2 and the signal processing unit 103 in Figure 3 are electrically connected via connection wiring provided for each pixel.

[0022] The vertical scanning circuit section 110 receives control pulses supplied from the control pulse generation section 115 and supplies control pulses to each pixel. Logic circuits such as a shift register and an address decoder are used in the vertical scanning circuit section 110.

[0023] The signal output from the photoelectric conversion element 102 of the pixel is processed by the signal processing unit 103. The signal processing unit 103 is equipped with a counter and memory, and digital values ​​are stored in the memory.

[0024] The horizontal scanning circuit unit 111 inputs control pulses to the signal processing unit 103 to sequentially select each column in order to read the signal from the memory of each pixel in which the digital signal is held.

[0025] For the selected column, a signal is output from the signal processing unit 103 of the pixel selected by the vertical scanning circuit unit 110 to the signal line 113.

[0026] The signal output to signal line 113 is output via output circuit 114 to an external recording unit or signal processing unit of the photoelectric converter 100.

[0027] In Figure 2, the arrangement of photoelectric conversion elements in the pixel region may be one-dimensional. Furthermore, it is possible to obtain the effects of the embodiment of the present invention even with just one pixel, and the case with one pixel is also included in the present invention. The function of the signal processing unit does not necessarily need to be provided for each photoelectric conversion element; for example, one signal processing unit may be shared by multiple photoelectric conversion elements, and signal processing may be performed sequentially.

[0028] As shown in Figures 2 and 3, multiple signal processing units 103 are arranged in the region that overlaps with the pixel region 12 in a plan view. The vertical scanning circuit unit 110, horizontal scanning circuit unit 111, column circuit 112, output circuit 114, and control pulse generation unit 115 are arranged so as to overlap between the edge of the sensor substrate 11 and the edge of the pixel region 12 in a plan view. In other words, the sensor substrate 11 has a pixel region 12 and a non-pixel region arranged around the pixel region 12, and the vertical scanning circuit unit 110, horizontal scanning circuit unit 111, column circuit 112, output circuit 114, and control pulse generation unit 115 are arranged in the region that overlaps with the non-pixel region in a plan view.

[0029] Figure 4 is an example of a block diagram including the equivalent circuits of Figures 2 and 3.

[0030] In Figure 2, the photoelectric conversion element 102 having the APD201 is provided on the sensor substrate 11, and the other components are provided on the circuit board 21.

[0031] The APD201 is a photoelectric converter that generates charge pairs corresponding to incident light through photoelectric conversion. A voltage VL (first voltage) is supplied to the anode of the APD201. A voltage VH (second voltage), which is higher than the voltage VL supplied to the anode, is supplied to the cathode of the APD201. A reverse bias voltage is supplied to the anode and cathode such that the APD201 performs avalanche multiplication. By supplying these voltages, the charge generated by the incident light undergoes avalanche multiplication, and an avalanche current is generated.

[0032] Furthermore, when a reverse bias voltage is supplied, there are two modes: Geiger mode, in which the device operates with a potential difference between the anode and cathode greater than the breakdown voltage, and linear mode, in which the device operates with a potential difference between the anode and cathode near or below the breakdown voltage.

[0033] An APD operating 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 operate in linear mode or Geiger mode. In the case of a SPAD, the potential difference is larger compared to a linear mode APD, and the voltage withstand effect is more pronounced, so it is preferable to use a SPAD.

[0034] The quench element 202 is connected to the power supply that provides voltage VH and to the APD201. When the signal is amplified by avalanche multiplication, the quench element 202 functions as a load circuit (quench circuit), suppressing the voltage supplied to the APD201 and thereby suppressing avalanche multiplication (quench operation). In addition, the quench element 202 also works to restore the voltage supplied to the APD201 to voltage VH by flowing the current that compensates for the voltage drop caused by the quench operation (recharge operation).

[0035] The signal processing unit 103 includes a waveform shaping unit 210, a counter circuit 211, and a selection circuit 212. In this specification, the signal processing unit 103 may include any one of the waveform shaping unit 210, the counter circuit 211, or the selection circuit 212.

[0036] The waveform shaping unit 210 shapes the cathode potential change of the APD201 obtained during photon detection and outputs a pulse signal. For example, an inverter circuit can be used as the waveform shaping unit 210. Figure 4 shows an example in which one inverter is used as the waveform shaping unit 210, but a circuit in which multiple inverters are connected in series may be used, or other circuits that have a waveform shaping effect may be used.

[0037] The counter circuit 211 counts the pulse signal output from the waveform shaping unit 210 and holds the count value. When the control pulse pRES is supplied via the drive line 213, the signal held by the counter circuit 211 is reset.

[0038] The selection circuit 212 receives a control pulse pSEL from the vertical scanning circuit section 110 in Figure 3 via the drive line 214 (not shown in Figure 3) in Figure 4, which switches the electrical 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.

[0039] A switch such as a transistor may be placed between the quench element 202 and the APD201, or between the photoelectric conversion element 102 and the signal processing unit 103, to switch the electrical connection. Similarly, the supply of voltage VH or voltage VL to the photoelectric conversion element 102 may be electrically switched using a switch such as a transistor.

[0040] In this embodiment, a configuration using a counter circuit 211 is shown. However, instead of the counter circuit 211, a photoelectric converter 100 may be used that acquires pulse detection timing using a Time to Digital Converter (TDC) and 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. A control pulse pREF (reference signal) is supplied to the TDC via a drive line from the vertical scanning circuit unit 110 in Figure 1 to measure the timing of the pulse signal. The TDC acquires the signal as a digital signal when the input timing of the signal output from each pixel via the waveform shaping unit 210 is relative to the control pulse pREF.

[0041] Figure 5 schematically illustrates the relationship between the operation of the APD and the output signal.

[0042] Figure 5(a) is an excerpt of the APD201, quench element 202, and waveform shaping unit 210 from Figure 4. Here, the input side of the waveform shaping unit 210 is denoted as nodeA and the output side as nodeB. Figure 5(b) shows the waveform change at nodeA in Figure 5(a), and Figure 5(c) shows the waveform change at nodeB in Figure 5(a).

[0043] Between time t0 and time t1, a potential difference of VH-VL is applied to APD201 in Figure 5(a). When a photon is incident on APD201 at time t1, avalanche multiplication occurs in APD201, an avalanche multiplication current flows through the quench element 202, and the voltage at nodeA drops. As the voltage drop increases further and the potential difference applied to APD201 decreases, the avalanche multiplication of APD201 stops as at time t2, and the voltage level at nodeA stops dropping below a certain value. Subsequently, between time t2 and time t3, a current flows through nodeA to compensate for the voltage drop from voltage VL, and at time t3, nodeA settles to its original potential level. At this time, any portion of the output waveform at nodeA that exceeds a certain threshold is waveform-shaped by the waveform shaping unit 210 and output as a signal at nodeB.

[0044] Note that the arrangement of the signal line 113, the column circuit 112, and the output circuit 114 is not limited to Figure 3. For example, the signal line 113 may be arranged extending in the row direction, and the column circuit 112 may be located at the end of the signal line 113.

[0045] The following describes the photoelectric conversion device for each embodiment.

[0046] (First Embodiment) A photoelectric conversion device according to the first embodiment will be described using Figures 6 to 12.

[0047] Figure 6 is a cross-sectional view of two pixels of the photoelectric conversion element 102 of the photoelectric conversion device of the present invention, taken perpendicular to the plane direction of the substrate.

[0048] The structure of the photoelectric conversion element 102 will now be described. The photoelectric conversion element 102 has an N-type first semiconductor region 311, a fourth semiconductor region 314, a sixth semiconductor region 316, and a seventh semiconductor region 317. Furthermore, it includes a P-type second semiconductor region 312, a third semiconductor region 313, a fifth semiconductor region 315, and a sixth semiconductor region 318.

[0049] In this embodiment, in the cross-section shown in Figure 6, an N-type first semiconductor region 311 is formed near the surface facing the incident light surface, and an N-type seventh semiconductor region 317 is formed around it. A P-type second semiconductor region 312 is formed at a position that overlaps the first and second semiconductor regions in a plan view. An N-type fourth semiconductor region 314 is further arranged at a position that overlaps the second semiconductor region 312 in a plan view, and an N-type sixth semiconductor region 316 is formed around it.

[0050] 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 that of the first semiconductor region 311, the entire region of the second semiconductor region 312 becomes a depletion layer region. Furthermore, this depletion layer region extends to a portion of the first semiconductor region 311, inducing a strong electric field in the extended depletion layer region. This strong electric field causes avalanche multiplication in the depletion layer region extending to a portion of the first semiconductor region 311, and a current based on the amplified charge is output as a signal charge. When light incident on the photoelectric converter 102 is photoelectrically converted and avalanche multiplication occurs in this depletion layer region (avalanche multiplication region), the generated charge of the first conductivity type is collected in the first semiconductor region 311.

[0051] In Figure 6, the fourth semiconductor region 314 and the seventh semiconductor region 317 are formed to be of roughly the same size, but the size of each semiconductor region is not limited to this. For example, the fourth semiconductor region 314 may be formed to be larger than the seventh semiconductor region 317, thereby collecting charge from a wider area to the first semiconductor region 311.

[0052] A textured structure 325 is formed on the surface of the semiconductor layer on the light incident side by trenches. The textured structure 325 is surrounded by a P-type third semiconductor region 313, scattering the light incident on the photoelectric conversion element 102. Since the incident light travels diagonally through the photoelectric conversion element, an optical path length greater than the thickness of the semiconductor layer 301 can be secured, making it possible to photoelectrically convert longer wavelength light compared to the case without the textured structure 325. In addition, the textured structure 325 prevents reflection of incident light within the substrate, thus improving the photoelectric conversion efficiency of the incident light.

[0053] The fourth semiconductor region 314 and the uneven structure 325 are formed to overlap in a plan view. The area where the fourth semiconductor region 314 and the uneven structure 325 overlap in a plan view is larger than the area of ​​the portion of the fourth semiconductor region 314 that does not overlap with the uneven structure 325. Charges generated at a position far from the avalanche multiplication region formed between the first semiconductor region 311 and the fourth semiconductor region 314 have a longer travel time to reach the avalanche multiplication region compared to charges generated at a position close to the avalanche multiplication region. Therefore, timing jitter may worsen. By positioning the fourth semiconductor region 314 and the uneven structure 325 to overlap in a plan view, the electric field deep within the photodiode can be increased, and the collection time of charges generated at a position far from the avalanche multiplication region can be shortened, thus reducing timing jitter.

[0054] Furthermore, the third semiconductor region 313 covers the uneven structure in three dimensions, thereby suppressing the generation of thermally excited charges at the interface of the uneven structure. This suppresses the Dark Count Rate (DCR) of the photoelectric conversion element.

[0055] Pixels are separated from each other by a pixel isolation section 324 with a trench structure, and a P-type fifth semiconductor region 315 formed around it separates adjacent photoelectric conversion elements from each other by a potential barrier. Since the photoelectric conversion elements are also separated by the potential of the fifth semiconductor region 315, it is not essential to define a pixel isolation structure by a trench structure such as the pixel isolation section 324. Also, when providing the pixel isolation section 324, its depth and position are not limited to the configuration of FIG. 6. The pixel isolation section 324 may be a DTI (deep trench isolation) that penetrates the semiconductor layer, or a DTI that does not penetrate the semiconductor layer. Metal may be embedded in the DTI to improve the light shielding performance. The pixel isolation section 324 may be configured to surround the entire periphery of the photoelectric conversion element in plan view, or may be configured, for example, only at the opposite sides of the photoelectric conversion element.

[0056] The distance from the pixel isolation section to the pixel isolation section of an adjacent pixel or a pixel provided at the closest position can also be regarded as the size of one photoelectric conversion element 102. When the size of one photoelectric conversion element 102 is L, the distance d from the light incident surface to the avalanche multiplication region satisfies L√2 / 4 < d < L×√2. When the size and depth of the photoelectric conversion element satisfy this relational expression, the strength of the electric field in the depth direction and the strength of the electric field in the plane direction in the vicinity of the first semiconductor region 311 become approximately the same. Since the variation in the time required for charge collection can be suppressed, the generation of timing jitter can be reduced.

[0057] On the light incident surface side of the semiconductor layer, a pinning film 321, a planarization film 322, and a microlens 323 are further formed. A filter layer (not shown) or the like may be further arranged on the light incident surface side. Various optical filters such as a color filter, an infrared cut filter, and a monochrome filter can be used for the filter layer. For the color filter, an RGB color filter, an RGBW color filter, etc. can be used.

[0058] Also, in the photoelectric conversion device according to the present embodiment, an antireflection film 326 and a light shielding portion 328 having an opening 327 are provided between the semiconductor layer 301 and the interlayer film 322.

[0059] The refractive index of the anti-reflective film 326 is lower than the effective refractive index of the uneven structure 325. Here, the effective refractive index is the actual refractive index of the entire uneven structure 325, which includes the substrate in which the trenches are formed and the material filling the trenches. For example, if the semiconductor layer 301 is Si with a refractive index of 4 and the interlayer film 322 is SiO with a refractive index of 1.5, the effective refractive index of the uneven structure 325 is 2.8 to 3.8. The anti-reflective film is, for example, Ta2O5, and its refractive index is around 2. By providing the anti-reflective film 326 between the semiconductor layer 301 and the interlayer film 322, the change in refractive index from the semiconductor layer 301 to the interlayer film 322 can be made smoother. This prevents reflection of avalanche light on the back surface of the semiconductor layer and reduces crosstalk caused by avalanche light.

[0060] The aperture 327 is provided so as to enclose the first semiconductor region 311 in a plan view from a direction perpendicular to the light incident surface. By providing light-shielding portions 328 between pixels, crosstalk caused by avalanche light emitted from each pixel entering adjacent pixels when it exits the pixel can be reduced.

[0061] This configuration allows for scattering of incident light within the pixel, thereby securing an optical path length greater than the thickness of the semiconductor layer, enabling photoelectric conversion of longer wavelength light, and efficiently diverting the avalanche emission light (described later) outside the semiconductor layer.

[0062] Figure 7 is a top view of two pixels of the photoelectric converter according to the first embodiment, showing the position of the dotted line A in Figure 6. The uneven structure 325 is arranged within the pixels partitioned by the pixel separator 324. The microlens 323 is arranged along the pixel separator 324, and is positioned so that the uneven structure 325 and the fourth semiconductor region 314 overlap.

[0063] Figure 8 is an enlarged cross-sectional view of the two trench structures (dotted line B in Figure 7) at the point where the first groove, which extends in the first direction (the in-plane direction of the light incident surface, the first surface), and the second groove, which extends in the second direction intersect the first direction, intersect among the grooves constituting the uneven structure 325. In the following explanation, the part of the groove that does not intersect with other grooves, whether it is in the first or second direction, will be called the line part, and the part where grooves intersect will be called the cross part.

[0064] The trench structure forming the groove portion is composed of a material different from that of the third semiconductor region 313. For example, if the third semiconductor region 313 is silicon, the main components constituting the trench structure are silicon oxide films or silicon nitride films, but metals or organic materials may also be included. The trench is formed, for example, to a depth of 0.1 to 0.6 μm from the surface of the semiconductor layer. In order to sufficiently increase the diffraction of incident light, it is desirable that the depth of the trench is greater than the width of the trench. Here, the width of the trench is the width from the interface between the pinning film 321 and the third semiconductor region 313 to the interface between the pinning film 321 and the third semiconductor region 313 in a plane passing through the centroid of the trench cross-section, and the depth of the trench is the depth from the light incident surface to the bottom of the trench.

[0065] The grooves constituting the uneven structure in Figure 8 are filled with a filler member 332. When the third semiconductor region 313 is silicon, the filler member is, for example, a silicon oxide film or a silicon nitride film, but metals or organic materials may also be used as fillers. Gaps 331 are arranged inside the filler member to enhance the change in refractive index caused by the uneven structure 325. The filler member is formed to fill the grooves of the uneven structure 325 and cover the pinning film 321 provided within the grooves.

[0066] Here, the void 331 is formed from the upper end of the pinning film 321 to a depth of 2 / 3 of the depth of the groove in the uneven structure 325, and does not come into contact with the bottom of the trench structure. This is to prevent the void 331 from reaching the bottom of the trench, which would eliminate the change in refractive index between the void 331 and the filling member 332, thus preventing increased reflection at the bottom of the trench and causing a decrease in sensitivity. In the example shown in Figure 9, the upper end of the void 331 coincides with the surface of the pinning film 321.

[0067] Figure 9 is a top view of the uneven structure 325, showing the locations where the voids 331 occur relative to the uneven structure 325. When the uneven structure 325 is arranged in a grid pattern as shown in Figure 7, the voids 331 occur at the intersections (cross points) of the grooves that form the uneven structure 325.

[0068] The trench formation process is described below. First, a groove is formed in the third semiconductor region 313 of the semiconductor layer by etching.

[0069] Subsequently, a pinning film 321 is formed on the surface of the third semiconductor region 313 and inside the trench using a method such as chemical vapor deposition (CDV).

[0070] The inside of the trench, covered with the pinning film 321, is further filled with a filler material 332. The filler material 332 is filled, for example, using chemical vapor deposition (CVD). CVD methods include thermal CVD, plasma CVD, and reduced-pressure CVD. Sol-gel filling is also possible. In this case, by optimizing the CVD film deposition conditions, the deposition rate can be increased at the corners compared to the flat areas. As the corners close before the flat areas, voids 331 are formed within the groove.

[0071] In the uneven structure 325 formed by a grid of grooves, the line width of the line portion is constant, and when the line portions intersect at right angles at the cross portion, the line width in the diagonal direction of the cross portion is √2 times wider than the line width in the opposite side direction of the line portion. Therefore, when the groove portion is filled with the filling member 332, the line portion is closed before the cross portion is closed. In the line portion, the corners close before the flat portion, but since gas is supplied from the unclosed portion of the cross portion, the filling member 332 fills the entire line portion faster than the cross portion is closed. Therefore, large voids 331 that are formed in the cross portion are not formed in the line portion.

[0072] When the void 331 is uniformly and continuously formed throughout the grooves of the uneven structure 325, the incident light is strongly diffracted in a specific direction due to the symmetry of the refractive index change caused by the void 331. Therefore, the increase in optical path length is limited, and optical color mixing to adjacent pixels may increase. As shown in Figure 9, when the void 331 is present only at the intersections of the grooves of the uneven structure 325, the incident light is strongly diffracted in oblique directions as well, allowing the optical path length to be increased. This enhances the effect of improving sensitivity to near-infrared light. In addition, the angle of incidence of light to adjacent pixels increases, resulting in a reduction in optical color mixing.

[0073] The trenches forming the uneven structure 325 can be embedded using the same process as the trenches constituting the pixel separation section 324. In this case, the side walls of the trenches forming the uneven structure 325 and the side walls of the trenches constituting the pixel separation section will have equivalent impurity concentrations. The structural differences between the trenches forming the uneven structure 325 and the trenches constituting the pixel separation section 324 will be explained below.

[0074] Figure 10(a) is an enlarged view of the cross-sectional uneven structure 325 and pixel separation 324 along the dotted line B in Figure 7, and Figure 10(b) is an enlarged view of the cross-sectional uneven structure 325 and pixel separation 324 along the dotted line C in Figure 7.

[0075] The pixel separation section 324 is a trench structure with a depth that penetrates the semiconductor region 313, and the same filling material 332 is used to fill both the pixel separation section 324 and the uneven structure 325 simultaneously. The filling material 332 may be the aforementioned silicon oxide film, silicon nitride film, metal, or organic material. The process can be simplified by filling the pixel separation section 324 and the uneven structure 325 using the same process.

[0076] A void 333 is formed in the filling material 332 of the pixel separation section 324. The void 333 is located in the pixel separation section 324 whether it is in the cross section corresponding to the cross section (dotted line B) or the line section (dotted line C) of the uneven structure 325. On the other hand, as mentioned above, the void 331 located in the uneven structure 325 is formed in the cross section (dotted line B) of the uneven structure 325, but not in the cross section (dotted line C) of the line section. The pixel separation section 324, which is a separation structure formed to prevent light leakage to adjacent pixels, has a wider line width than the uneven structure 325, and therefore voids are more easily formed in the pixel separation section 324. In other words, the width of the pixel separation section 324 in the third direction, which is the in-plane direction of the first surface, is wider than the width of the groove section forming the uneven structure 325 in the third direction. Since voids have a lower light transmittance compared to the filling material, forming voids in the separation structure improves the effect of preventing light leakage to adjacent pixels.

[0077] Furthermore, the upper end of the void 333 (the end on the first surface side) is positioned deeper relative to the light incident surface than the upper end of the void 331, and the lower end of the void 333 (the end on the second surface side) is positioned deeper relative to the light incident surface than the lower end of the void 331. In other words, the shortest distance from the first surface (light incident surface) to the end of the void 333 located within the separation section 324 on the second surface side (the surface facing the light incident surface) is greater than the shortest distance from the light incident surface to the end of the void 331 located in the uneven structure 325 on the surface facing the incident surface. As mentioned above, the pixel separation section 324 has a wide line width, so more filling material is required to fill the trench. By filling so that a void is formed at the bottom, the filling material inside the trench can be closed with less filling material.

[0078] Furthermore, the gaps 331 and 333 can be formed at any position depending on the trench pattern, the tapered shape of the trenches, and the method of filling the filling member 324.

[0079] (Second embodiment) A photoelectric conversion device according to the second embodiment will be described with reference to Figure 11.

[0080] Parts that are common to the description of the first embodiment will be omitted, and the parts that differ mainly from the first embodiment will be described. In this embodiment, gaps 331 are also formed in the line portions of the uneven structure 325.

[0081] Figure 11 is a plan view of one pixel of the uneven structure 325 of the photoelectric conversion device according to the second embodiment, showing the planar position of the voids 331 in the lattice-like arrangement of the uneven structure 325.

[0082] In this embodiment, the void 331 is arranged not only in the cross section but also in the line section. A reinforcement member 332 is placed between the void 331 in the cross section and the void 331 in the line section, so that the void 331 in the cross section and the void 331 in the line section are not connected. By arranging the void 331 in the cross section and the void 331 in the line section separately, diffraction is strengthened by the refractive index difference between the void 331 and the filling member 332, thereby increasing sensitivity to near-infrared rays.

[0083] (Third embodiment) A photoelectric conversion device according to a third embodiment will be described with reference to Figure 12.

[0084] Parts that are common to the description of the first embodiment will be omitted, and the parts that differ mainly from the first embodiment will be described. In this embodiment, a gap 331 is formed in a part of the line portion of the uneven structure 325.

[0085] Figure 12 is a plan view of one pixel of the uneven structure 325 according to the third embodiment, showing the planar position of the voids 331 in the grid-like arrangement of the uneven structure 325. The voids 331 are located in the cross portions and in parts of the line portions of the uneven structure 325. Here, the voids 331 are located in the line portions, which correspond to areas close to the center of the pixel where a lot of light is incident.

[0086] By increasing the line width of the grooves forming the uneven structure 325, the closure of the grooves by the filling member 332 is delayed, and voids are created. Therefore, by making the line width of the grooves where voids are to be created thicker than the line width of the grooves where voids are not to be created, voids can be formed at desired locations. For example, by making the line width of the grooves where voids are to be created √2 times the line width of the grooves where voids are not to be created, voids 331 equivalent to those in the cross sections can be formed. By controlling the arrangement of voids in the uneven structure 325 in this way, the sensitivity and optical color mixing can be controlled to match the characteristics of the photoelectric converter.

[0087] (Fourth embodiment) The photoelectric conversion system according to this embodiment will be described with reference to Figure 13. Figure 13 is a block diagram showing the schematic configuration of the photoelectric conversion system according to this embodiment.

[0088] The photoelectric conversion devices described in the first to sixth embodiments above are applicable to various photoelectric conversion systems. Examples of applicable photoelectric conversion systems include digital still cameras, digital camcorders, surveillance cameras, photocopiers, fax machines, mobile phones, in-vehicle cameras, and observation satellites. Camera modules, which include optical systems such as lenses and imaging devices, are also included in photoelectric conversion systems. Figure 13 shows a block diagram of a digital still camera as an example of these.

[0089] The photoelectric conversion system illustrated in Figure 13 includes an imaging device 1004, which is an example of a photoelectric conversion device, and a lens 1002 that forms an optical image of a subject onto the imaging device 1004. Furthermore, it has an aperture 1003 for varying the amount of light passing through the lens 1002, and a barrier 1001 for protecting the lens 1002. The lens 1002 and aperture 1003 are an optical system that focuses light onto the imaging device 1004. The imaging device 1004 is a photoelectric conversion device of any of the above embodiments, which converts the optical image formed by the lens 1002 into an electrical signal.

[0090] The photoelectric conversion system also includes a signal processing unit 1007, which is an image generation unit that generates an image by processing the output signal output from the imaging device 1004. The signal processing unit 1007 performs various corrections and compressions as needed and outputs the image data. The signal processing unit 1007 may be formed on the semiconductor substrate on which the imaging device 1004 is mounted, or it may be formed on a semiconductor substrate separate from the imaging device 1004.

[0091] 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. Furthermore, the photoelectric conversion system includes a recording medium 1012 such as a semiconductor memory for recording or reading imaging data, and a recording medium control interface unit (recording medium control I / F unit) 1011 for recording or reading data from the recording medium 1012. The recording medium 1012 may be built into the photoelectric conversion system or may be detachable.

[0092] Furthermore, the photoelectric conversion system includes an overall control / calculation unit 1009 that controls various calculations and the entire digital still camera, and a timing generation unit 1008 that outputs various timing signals to the imaging device 1004 and the signal processing unit 1007. Here, the timing signals and the like may be input from an external source, and the photoelectric conversion system only needs to have at least the imaging device 1004 and the signal processing unit 1007 that processes the output signals output from the imaging device 1004.

[0093] The imaging device 1004 outputs the imaging signal to the 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.

[0094] Thus, according to this embodiment, a photoelectric conversion system can be realized by applying a photoelectric conversion device (imaging device) of any of the above embodiments.

[0095] (Fifth embodiment) The photoelectric conversion system and mobile unit of this embodiment will be described with reference to Figure 14. Figure 14 is a diagram showing the configuration of the photoelectric conversion system and mobile unit of this embodiment.

[0096] Figure 14(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 a photoelectric conversion device as described in any of the embodiments above. 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 a 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 the 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, distance information is information related to parallax, defocus amount, distance to an object, etc. The collision determination unit 1318 may use any of this distance information to determine the possibility of a collision. The distance information acquisition means may be implemented by specially designed hardware or by a software module. It may also be implemented by an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or a combination thereof.

[0097] The photoelectric conversion system 1300 is connected to the vehicle information acquisition device 1320 and can acquire vehicle information such as vehicle speed, yaw rate, and steering angle. The photoelectric conversion system 1300 is also connected to the control ECU 1330, which is a control unit that outputs a control signal to generate braking force on the vehicle based on the judgment result of the collision judgment unit 1318. The photoelectric conversion system 1300 is also connected to the warning device 1340, which issues a warning to the driver based on the judgment result of the collision judgment unit 1318. For example, if the collision judgment result of the collision judgment unit 1318 indicates a high probability of collision, the control ECU 1330 performs vehicle control to avoid a collision or mitigate damage by applying the brakes, releasing the accelerator, or suppressing engine output. The warning device 1340 warns the user by sounding an alarm, displaying warning information on a screen such as a car navigation system, or vibrating the seat belt or steering wheel.

[0098] In this embodiment, the photoelectric conversion system 1300 images the area around the vehicle, for example, the front or rear. Figure 14(b) shows the photoelectric conversion system when imaging the area in front of the vehicle (imaging range 1350). The 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.

[0099] The above example illustrates control to prevent collisions with other vehicles, but it can also be applied to control systems that automatically follow other vehicles or automatically drive to prevent vehicles from straying from their lanes. Furthermore, the photoelectric conversion system can be applied not only to vehicles such as the vehicle itself, but also to mobile objects (mobile devices) such as ships, aircraft, or industrial robots. In addition, it can be applied not only to mobile objects but also to a wide range of devices that utilize object recognition, such as intelligent transportation systems (ITS).

[0100] (Sixth embodiment) The photoelectric conversion system of this embodiment will be described with reference to Figure 15. Figure 15 is a block diagram showing an example configuration of a distance image sensor, which is the photoelectric conversion system of this embodiment.

[0101] As shown in Figure 15, the distance image sensor 401 is configured to include an optical system 407, a photoelectric converter 408, an image processing circuit 404, a monitor 405, and a memory 406. The distance image sensor 401 receives 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, thereby acquiring a distance image corresponding to the distance to the subject.

[0102] The optical system 407 is composed of one or more lenses and guides the image light (incident light) from the subject to the photoelectric converter 408, where it forms an image on the light-receiving surface (sensor part) of the photoelectric converter 408.

[0103] The photoelectric converter 408 is one of the photoelectric converters from each of the embodiments described above, and a distance signal indicating the distance obtained from the light received signal output from the photoelectric converter 408 is supplied to the image processing circuit 404.

[0104] The image processing circuit 404 performs image processing to construct a distance image based on the distance signal supplied from the photoelectric converter 408. The distance image (image data) obtained through this image processing is then supplied to the monitor 405 for display or supplied to the memory 406 for storage (recording).

[0105] With the distance image sensor 401 configured in this way, by applying the photoelectric conversion device described above, the characteristics of the pixels are improved, and for example, more accurate distance images can be acquired.

[0106] (Seventh Embodiment) The photoelectric conversion system of this embodiment will be described with reference to Figure 16. Figure 16 is a diagram showing an example of a schematic configuration of an endoscopic surgical system, which is the photoelectric conversion system of this embodiment.

[0107] Figure 16 illustrates a surgeon (physician) 1131 performing surgery on a patient 1132 on a patient bed 1133 using an endoscopic surgical system 1150. As shown in the figure, the endoscopic surgical system 1150 consists of an endoscope 1100, surgical instruments 1110, and a cart 1134 equipped with various devices for endoscopic surgery.

[0108] The endoscope 1100 consists of a barrel 1101, the tip of which is inserted into the body cavity of the patient 1132 for a predetermined length, and a camera head 1102 connected to the base end of the barrel 1101. In the illustrated example, the endoscope 1100 is shown as a so-called rigid endoscope having a rigid barrel 1101, but the endoscope 1100 may also be configured as a so-called flexible endoscope having a flexible barrel.

[0109] An opening into which an objective lens is fitted is provided at the tip of the endoscope tube 1101. A light source device 1203 is connected to the endoscope 1100, and the light generated by the light source device 1203 is guided to the tip of the endoscope tube by a light guide extending inside the endoscope tube 1101, and is irradiated through the objective lens towards the object to be observed inside the body cavity of the patient 1132. The endoscope 1100 may be a straight-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0110] The camera head 1102 contains an optical system and a photoelectric converter. Reflected light from the object being observed (observation light) is focused by the optical system into the photoelectric converter. The photoelectric converter converts the observation light into electrical signals, generating an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The photoelectric converter can be any of the photoelectric converters described in the embodiments described above. The image signal is transmitted as RAW data to the camera control unit (CCU) 1135.

[0111] The CCU1135 consists of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and other components, and comprehensively controls the operation of the endoscope 1100 and the display device 1136. Furthermore, the CCU1135 receives an image signal from the camera head 1102 and performs various image processing operations on that image signal, such as development processing (demosaic processing), to display the image based on that image signal.

[0112] The display device 1136 displays an image based on an image signal that has been processed by the CCU 1135, under control from the CCU 1135.

[0113] The light source device 1203 consists of a light source such as an LED (Light Emitting Diode) and supplies illumination light to the endoscope 1100 when photographing the surgical area, etc.

[0114] The input device 1137 is an input interface for the endoscopic surgical system 1150. The user can input various types of information and instructions to the endoscopic surgical system 1150 via the input device 1137.

[0115] The treatment instrument control device 1138 controls the driving of the energy treatment instrument 1112 for purposes such as tissue cauterization, incision, or blood vessel sealing.

[0116] The light source device 1203, which supplies illumination light to the endoscope 1100 when photographing the surgical area, can be composed of, for example, an LED, a laser light source, or a combination thereof. When the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so the white balance of the captured image can be adjusted in the light source device 1203. In this case, it is also possible to capture images corresponding to each of the RGB colors in time-division by irradiating the observation target with laser light from each of the RGB laser light sources in time-division and controlling the drive of the image sensor of the camera head 1102 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter on the image sensor.

[0117] 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 drive of the image sensor of the camera head 1102 in synchronization with the timing of the change in light intensity, images can be acquired in time-division order, and these images can be combined to generate high dynamic range images without so-called black crushing and white clipping.

[0118] Furthermore, the light source device 1203 may be configured to supply light in a predetermined wavelength band corresponding to special light observation. In special light observation, for example, the wavelength dependence of light absorption in body tissue is utilized. Specifically, by irradiating with narrowband light compared to the irradiation light used during normal observation (i.e., white light), predetermined tissues such as blood vessels on the surface of mucosa can be imaged with high contrast. Alternatively, in special light observation, fluorescence observation may be performed to obtain an image from fluorescence generated by irradiation with excitation light. In fluorescence observation, excitation light can be irradiated onto body tissue and fluorescence from the body tissue can be observed, or a reagent such as indocyanine green (ICG) can be injected into body tissue and excitation light corresponding to the fluorescence wavelength of the reagent can be irradiated onto the body tissue to obtain a fluorescence image. The light source device 1203 may be configured to supply narrowband light and / or excitation light corresponding to such special light observation.

[0119] (Eighth embodiment) The photoelectric conversion system of this embodiment will be described using Figures 17(a) and (b). Figure 17(a) illustrates the eyeglasses 1600 (smart glasses), which are the photoelectric conversion system of this embodiment. The eyeglasses 1600 have a photoelectric conversion device 1602. The photoelectric conversion device 1602 is the photoelectric conversion device described in each of the embodiments described above. In addition, 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. There may be one or more photoelectric conversion devices 1602. In addition, multiple types of photoelectric conversion devices may be used in combination. The arrangement position of the photoelectric conversion device 1602 is not limited to that shown in Figure 17(a).

[0120] The eyeglasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the photoelectric converter 1602 and the display device. The control device 1603 also controls the operation of the photoelectric converter 1602 and the display device. The lens 1601 has an optical system formed therein for focusing light onto the photoelectric converter 1602.

[0121] Figure 17(b) illustrates a pair of glasses 1610 (smart glasses) according to one application example. The glasses 1610 have a control device 1612, which is equipped with a photoelectric converter equivalent to a photoelectric converter 1602 and a display device. The lens 1611 has an optical system formed therein for projecting light emitted from the photoelectric converter in the control device 1612 and from the display device, and an image is projected onto the lens 1611. The control device 1612 functions as a power supply that provides power to the photoelectric converter and the display device, and also controls the operation of the photoelectric converter and the display device. The control device may have a gaze detection unit that detects the wearer's gaze. Gaze detection may use infrared light. The infrared light emitter emits infrared light towards the user's eyeball that is fixated on the displayed image. An imaging unit having a light-receiving element detects the reflected light from the eyeball of the emitted infrared light, thereby obtaining an image of the eyeball. By having a reduction means that reduces the light from the infrared light emitter to the display unit in planar view, the deterioration of image quality is reduced.

[0122] The user's gaze towards the displayed image is detected from an image of the eyeball obtained by imaging with infrared light. Any known method can be applied to gaze detection using an image of the eyeball. For example, a gaze detection method based on the Purkinje image obtained by the reflection of the irradiated light from the cornea can be used.

[0123] More specifically, gaze detection processing is performed based on the pupil-corneal reflection method. Using the pupil-corneal reflection method, a gaze vector representing the orientation (rotation angle) of the eyeball is calculated based on the pupil image and Purkinje image contained in the captured image of the eyeball, thereby detecting the user's gaze.

[0124] The display device of this embodiment includes a photoelectric converter having a light-receiving element, and may control the display image of the display device based on the user's gaze information from the photoelectric converter.

[0125] Specifically, the display device determines a first field of view that the user is fixated on, and a second field of view other than the first field of view, based on gaze information. The first and second field of view may be determined by the control device of the display device, or they may be determined by an external control device and received. Within the display area of ​​the display device, the display resolution of the first field of view may be controlled to be higher than that of the second field of view. In other words, the resolution of the second field of view may be lower than that of the first field of view.

[0126] Furthermore, the display area may have a first display area and a second display area different from the first display area, and a higher priority area may be determined from the first and second display areas based on line-of-sight information. The first and second field-of-sight areas may be determined by the control device of the display device, or they may be determined by an external control device and received. The resolution of the higher priority area may be controlled to be higher than the resolution of the areas other than the higher priority area. In other words, the resolution of areas with relatively lower priority may be set lower.

[0127] AI may be used to determine the first field of view area and the areas with higher priority. The AI ​​may be a model configured to estimate the angle of gaze and the distance to the target object at the end of the line of sight from the image of the eye, using the image of the eye and the direction the eye was actually looking in that image as training data. The AI ​​program may be installed in the display device, the photoelectric converter, or an external device. If installed in an external device, it will be transmitted to the display device via communication.

[0128] When display control is based on visual detection, this method is preferably applicable to smart glasses that further include a photoelectric converter for capturing images of the surrounding environment. The smart glasses can display the captured external information in real time.

[0129] [Modified Embodiment] The present invention is not limited to the embodiments described above and can be modified in various ways.

[0130] For example, examples in which some components of one embodiment are added to other embodiments, or replaced with some components of other embodiments, are also included as embodiments of the present invention.

[0131] Furthermore, the photoelectric conversion systems shown in the fourth and fifth embodiments above are merely 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 Figures 13 to 14. The same applies to the ToF system shown in the sixth embodiment, the endoscope shown in the seventh embodiment, and the smart glasses shown in the eighth embodiment.

[0132] It should be noted that the above embodiments are merely examples of how the present invention can be implemented, and the technical scope of the present invention should not be interpreted as being limited by them. In other words, the present invention can be implemented in various forms without departing from its technical concept or its main features. [Explanation of Symbols]

[0133] 201 Photoelectric conversion unit 325 Uneven structure 332 Filling material 331 void

Claims

1. A plurality of photoelectric conversion units are disposed on a semiconductor layer having a first surface which is a light incident surface and a second surface which is opposite to the first surface, Each of the aforementioned photoelectric conversion units is separated by a separation structure, The semiconductor layer has a plurality of grooves provided on the first surface of the photoelectric conversion section defined by the separation structure, The system comprises a third semiconductor region provided with the plurality of grooves, and a sixth semiconductor region adjacent to the second surface side of the third semiconductor region. The plurality of grooves are composed of a first groove extending in a first direction which is the in-plane direction of the first surface, and a second groove extending in a second direction which is the in-plane direction of the first surface and intersects the first direction. The conductivity types of the third semiconductor region and the conductivity types of the sixth semiconductor region are opposite to each other. The shortest distance from the first surface to the end of the plurality of grooves on the second surface side is shorter than the shortest distance from the first surface to the sixth semiconductor region. A photoelectric conversion device characterized in that a filling member and a void are arranged in the groove at the point where the first groove and the second groove intersect.

2. The photoelectric conversion device according to claim 1, characterized in that a filling member and a void are arranged within the separation structure.

3. A plurality of photoelectric conversion units disposed on a semiconductor layer having a first surface which is a light incident surface and a second surface which is opposite to the first surface, Each of the aforementioned photoelectric conversion units is separated by a separation structure, The aforementioned semiconductor layer is Multiple grooves provided on the first surface, The system comprises a third semiconductor region provided with the plurality of grooves, and a sixth semiconductor region adjacent to the second surface side of the third semiconductor region. The conductivity types of the third semiconductor region and the conductivity types of the sixth semiconductor region are opposite to each other. The shortest distance from the first surface to the end of the plurality of grooves on the second surface side is shorter than the shortest distance from the first surface to the sixth semiconductor region. A photoelectric conversion device characterized in that a filling member and voids are arranged within the grooves of the plurality of grooves and within the separation structure.

4. The photoelectric conversion device according to claim 3, characterized in that the void is located within a groove at the intersection of a first groove extending in a first direction which is the in-plane direction of the first surface and a second groove extending in a second direction which is the in-plane direction of the first surface and intersects the first direction.

5. The shortest distance from the first surface to the end of the void located within the separation structure on the second surface side is: The photoelectric conversion device according to any one of claims 2 to 4, characterized in that it is greater than the shortest distance from the first surface to the end of the void disposed in the groove on the second surface side.

6. The length of the void disposed within the groove from the end on the first surface to the end on the second surface is: The photoelectric conversion device according to any one of claims 2 to 5, characterized in that the length of the gap in the separation structure is shorter than the length from the end on the first surface side to the end on the second surface side.

7. The photoelectric conversion device according to any one of claims 2 to 6, characterized in that the width of the separation structure in the third direction, which is the in-plane direction of the first surface, is wider than the width of the groove in the third direction.

8. The photoelectric conversion device according to any one of claims 1 to 7, characterized in that the filling member is disposed between the end of the groove on the second surface side and the end of the void disposed within the groove on the second surface side.

9. The photoelectric conversion device according to any one of claims 1 to 8, characterized in that the end of the void in the groove on the first surface side coincides with the first surface.

10. The photoelectric conversion device according to any one of claims 1, 2, or 4, characterized in that the space between the void located at the intersection of the first groove and the second groove and the void located in the first groove is filled with a filling material.

11. The photoelectric conversion device according to any one of claims 1 to 10, characterized in that the groove portion has a trench structure.

12. The photoelectric conversion device according to any one of claims 1 to 11, characterized in that the filling member is an oxide film or a nitride film.

13. A photoelectric conversion system having a photoelectric conversion device according to any one of claims 1 to 12, A light-emitting unit that emits light detected by the aforementioned photoelectric conversion device, A photoelectric conversion system characterized by having a calculation means for calculating distance using a digital signal held in the photoelectric conversion device.

14. It is a mobile object, A photoelectric conversion device according to any one of claims 1 to 12, Distance information acquisition means that acquires distance information to an object from a parallax image based on a signal from the aforementioned photoelectric converter, A mobile body characterized by having control means for controlling the mobile body based on the distance information.

Images