Photoelectric converter

Abstract

To provide a photoelectric conversion device in which signal loss is reduced.SOLUTION: A first photoelectric conversion part and a second photoelectric conversion part are arranged to align in a first direction, in a plan view with respect to a substrate. Sensitivity of a third photoelectric conversion part is lower than any of sensitivity of the first photoelectric conversion part and sensitivity of the second photoelectric conversion part. In the plan view, the third photoelectric conversion part is arranged along a portion of a circumference of an area including the first photoelectric conversion part and the second photoelectric conversion part.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses an image sensor including pixels configured such that a highly sensitive photoelectric conversion unit surrounds a less sensitive photoelectric conversion unit. Signals output from the highly sensitive photoelectric conversion unit and signals from the less sensitive photoelectric conversion unit are used for generating a high-dynamic-range image.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a photoelectric conversion device configured as described above, it is assumed that pixels having a configuration in which charges are transferred from a photoelectric conversion unit to a floating diffusion are employed. In this case, the floating diffusion can be disposed between a highly sensitive photoelectric conversion unit and a less sensitive photoelectric conversion unit. In such a configuration, signal loss may occur due to light guided near the center of the pixel entering the floating diffusion.

[0005] An object of the present invention is to provide a photoelectric conversion device with reduced signal loss.

Means for Solving the Problems

[0006] According to one disclosure of this specification, a substrate, a first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit, each disposed on the substrate and generating an electric charge based on incident light, a microlens disposed on the substrate in common with the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, a floating diffusion disposed on the substrate, a first transfer transistor disposed on the substrate and transferring the electric charge generated in the first photoelectric conversion unit to the floating diffusion, and a second photoelectric conversion unit disposed on the substrate and transferring the electric charge generated in the second photoelectric conversion unit to the floating diffusion The first photoelectric conversion unit and the second photoelectric conversion unit are arranged in a first direction in a plan view of the substrate, the sensitivity of the third photoelectric conversion unit is lower than that of the first photoelectric conversion unit and the second photoelectric conversion unit, and in the plan view, the third photoelectric conversion unit is arranged along a part of the outer periphery of a region including the first photoelectric conversion unit and the second photoelectric conversion unit. In the plan view, at least a portion of the third photoelectric conversion unit and at least a portion of the floating diffusion are arranged in order along a direction from the center of the microlens toward the outer circumference of the microlens. A photoelectric conversion device characterized by the above is provided.

[0007] According to another disclosure of this specification, a substrate, a first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit, each disposed on the substrate and generating an electric charge based on incident light, and a microlens disposed on the substrate in common with the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, A floating diffusion is disposed on the substrate and to which charge is transferred from the first photoelectric conversion unit, the second photoelectric conversion unit and the third photoelectric conversion unit, The third photoelectric conversion unit has a saturation charge amount that is less than the saturation charge amount of the first photoelectric conversion unit and the saturation charge amount of the second photoelectric conversion unit, and in a plan view with respect to the substrate, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged to be aligned in a first direction, and in a second direction perpendicular to the first direction, the centroid position of the third photoelectric conversion unit is different from the centroid position of the first photoelectric conversion unit and the centroid position of the second photoelectric conversion unit. In the plan view, at least a portion of the third photoelectric conversion unit and at least a portion of the floating diffusion are arranged in order along a direction from the center of the microlens toward the outer circumference of the microlens. A photoelectric conversion device characterized by the above is provided.

[0008] According to another disclosure of this specification, a substrate, a first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit, each disposed on the substrate and generating an electric charge based on incident light, and a microlens disposed on the substrate in common with the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, A floating diffusion is disposed on the substrate and to which charge is transferred from the first photoelectric conversion unit, the second photoelectric conversion unit and the third photoelectric conversion unit, The third photoelectric conversion unit has a saturation charge amount that is less than the saturation charge amount of the first photoelectric conversion unit and the saturation charge amount of the second photoelectric conversion unit, and in a plan view with respect to the substrate, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged to be aligned in a first direction, and in the first direction, the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the second photoelectric conversion unit is greater than the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the first photoelectric conversion unit. In the plan view, at least a portion of the third photoelectric conversion unit and at least a portion of the floating diffusion are arranged in order along a direction from the center of the microlens toward the outer circumference of the microlens. A photoelectric conversion device characterized by the above is provided. According to another disclosure of this specification, the present invention comprises a substrate, a first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit, each disposed on the substrate and generating an electric charge based on incident light, a microlens disposed on the substrate in common with the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, a floating diffusion disposed on the substrate, a first transfer transistor disposed on the substrate and transferring the electric charge generated in the first photoelectric conversion unit to the floating diffusion unit, a second transfer transistor disposed on the substrate and transferring the electric charge generated in the second photoelectric conversion unit to the floating diffusion unit, a third transfer transistor disposed on the substrate and transferring the electric charge generated in the third photoelectric conversion unit to the floating diffusion unit, and the substrate between the first photoelectric conversion unit and the second photoelectric conversion unit. A photoelectric conversion device is provided, comprising: a first separation unit disposed on the substrate; a second separation unit disposed on the substrate between the first photoelectric conversion unit and the third photoelectric conversion unit; and a third separation unit disposed on the substrate between the second photoelectric conversion unit and the third photoelectric conversion unit, wherein in a plan view with respect to the substrate, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged to be aligned in a first direction; the sensitivity of the third photoelectric conversion unit is lower than that of either the sensitivity of the first photoelectric conversion unit or the sensitivity of the second photoelectric conversion unit; in a plan view, the third photoelectric conversion unit is arranged along a part of the outer periphery of a single region including the first photoelectric conversion unit and the second photoelectric conversion unit; the impurity concentration in the second separation unit is higher than that of the first separation unit; and the impurity concentration in the third separation unit is higher than that of the first separation unit. According to another disclosure of this specification, a substrate, a first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit, each disposed on the substrate and generating an electric charge based on incident light, a microlens disposed on the substrate in common with the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, a floating diffusion disposed on the substrate, a first transfer transistor disposed on the substrate and transferring the electric charge generated in the first photoelectric conversion unit to the floating diffusion unit, a second transfer transistor disposed on the substrate and transferring the electric charge generated in the second photoelectric conversion unit to the floating diffusion unit, and a floating diffusion A photoelectric conversion device is provided, comprising a third transfer transistor that transfers to a ting diffusion, wherein in a plan view with respect to the substrate, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged to be aligned in a first direction, the sensitivity of the third photoelectric conversion unit is lower than that of the sensitivity of the first photoelectric conversion unit and the sensitivity of the second photoelectric conversion unit, in a plan view, the third photoelectric conversion unit is arranged along a part of the outer periphery of a single region including the first photoelectric conversion unit and the second photoelectric conversion unit, and in the first direction, the distance between the centroid position of the third photoelectric conversion unit and the centroid position of the second photoelectric conversion unit is greater than the distance between the centroid position of the third photoelectric conversion unit and the centroid position of the first photoelectric conversion unit. According to another disclosure of this specification, the device comprises a substrate, a first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit, each disposed on the substrate and generating an electric charge based on incident light, a microlens disposed on the substrate in common with the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, a first separator disposed on the substrate between the first photoelectric conversion unit and the second photoelectric conversion unit, a second separator disposed on the substrate between the first photoelectric conversion unit and the third photoelectric conversion unit, and a third separator disposed on the substrate between the second photoelectric conversion unit and the third photoelectric conversion unit, wherein the saturation charge amount of the third photoelectric conversion unit is the first light A photoelectric conversion device is provided, characterized in that the saturation charge amount of the electric power conversion unit is less than that of the saturation charge amount of the second photoelectric conversion unit, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged in a first direction in a plan view with respect to the substrate, the centroid position of the third photoelectric conversion unit is different from that of the centroid position of the first photoelectric conversion unit and the centroid position of the second photoelectric conversion unit in a second direction perpendicular to the first direction, the impurity concentration in the second separation unit is higher than that of the first separation unit, and the impurity concentration in the third separation unit is higher than that of the first separation unit. According to another disclosure of this specification, the device comprises a substrate, a first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit, each disposed on the substrate and generating an electric charge based on incident light, a microlens disposed on the substrate in common with the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, a first separator disposed on the substrate between the first photoelectric conversion unit and the second photoelectric conversion unit, a second separator disposed on the substrate between the first photoelectric conversion unit and the third photoelectric conversion unit, and a third separator disposed on the substrate between the second photoelectric conversion unit and the third photoelectric conversion unit, wherein the saturation charge amount of the third photoelectric conversion unit is determined by the first photoelectric conversion unit A photoelectric conversion device is provided, characterized in that the saturation charge amount of the first photoelectric conversion unit is less than the saturation charge amount of the second photoelectric conversion unit, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged in a first direction in a plan view with respect to the substrate, the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the second photoelectric conversion unit is greater than the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the first photoelectric conversion unit in the first direction, the impurity concentration in the second separation unit is higher than the impurity concentration in the first separation unit, and the impurity concentration in the third separation unit is higher than the impurity concentration in the first separation unit. [Effects of the Invention]

[0009] According to the present invention, a photoelectric conversion device with reduced signal loss is provided. [Brief explanation of the drawing]

[0010] [Figure 1] This block diagram shows a schematic configuration of the photoelectric conversion device according to the first embodiment. [Figure 2] This is a circuit diagram of a pixel according to the first embodiment. [Figure 3] This is a schematic plan view of a pixel according to the first embodiment. [Figure 4] This is a schematic cross-sectional view of a pixel according to the first embodiment. [Figure 5] This is a block diagram showing the schematic configuration of the photoelectric conversion device according to the second embodiment. [Figure 6] This is a circuit diagram of a pixel according to the second embodiment. [Figure 7] This is a schematic plan view of a pixel according to the second embodiment. [Figure 8] It is a schematic cross-sectional view of a pixel according to the second embodiment. [Figure 9] It is a schematic plan view of a pixel according to the third embodiment. [Figure 10] It is a schematic plan view of a pixel according to the fourth embodiment. [Figure 11] It is a schematic plan view of a pixel according to the fifth embodiment. [Figure 12] It is a circuit diagram of a pixel according to the sixth embodiment. [Figure 13] It is a schematic plan view of a pixel according to the sixth embodiment. [Figure 14] It is a schematic cross-sectional view of a pixel according to the seventh embodiment. [Figure 15] It is a block diagram of a device according to the eighth embodiment. [Figure 16] It is a block diagram of a device according to the ninth embodiment.

Modes for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described while referring to the drawings. Note that the present invention is not limited to the following embodiments, and can be appropriately modified without departing from the gist thereof. Also, in the drawings described below, elements having the same function are denoted by the same reference numerals, and the description thereof may be omitted or simplified.

[0012] In the following explanation, the semiconductor region of the first conductivity type, where the majority carriers are the same as the signal carriers, is assumed to be an N-type semiconductor region, and the semiconductor region of the second conductivity type is assumed to be a P-type semiconductor region. That is, in the following explanation, the signal carriers are assumed to be electrons. Furthermore, all transistors in the pixels are assumed to be N-type MOS transistors. However, the polarity and conductivity type may all be reversed. That is, the signal carriers may be holes, the semiconductor region of the first conductivity type may be a P-type semiconductor region, and the semiconductor region of the second conductivity type may be an N-type semiconductor region. In this case, the transistors in the pixels may be P-type MOS transistors. In this way, the conductivity type of transistors, etc., can be appropriately changed according to the polarity of the charge treated as a signal.

[0013] In the first to seventh embodiments described below, the imaging device will be described as an example of a photoelectric conversion device. However, the photoelectric conversion device in each embodiment is not limited to an imaging device and can also be applied to other photodetection devices based on photoelectric conversion. Examples of other photodetection devices include distance measuring devices and photometric devices. A distance measuring device may be, for example, a focus detection device or a distance measuring device using TOF (Time-Of-Flight). A photometric device may be a device that measures the amount of light incident on the device.

[0014] [First Embodiment] The first embodiment will be described with reference to Figures 1 to 4. Figure 1 is a block diagram showing the schematic configuration of the photoelectric converter 1 according to this embodiment. The photoelectric converter 1 includes a pixel array 10, a vertical scanning circuit 20, a column circuit 30, a horizontal scanning circuit 40, an output circuit 50, and a control circuit 60.

[0015] The control circuit 60 outputs control signals such as a vertical synchronization signal, a horizontal synchronization signal, and a clock signal to the vertical scanning circuit 20, the column circuit 30, and the horizontal scanning circuit 40. In this way, the control circuit 60 controls the operation of these circuits.

[0016] The pixel array 10 has multiple pixels 11 arranged in multiple rows and multiple columns in the row direction (horizontal direction in Figure 1) and column direction (vertical direction in Figure 1). Each of the multiple pixels 11 has a photoelectric conversion unit, which will be described later. As a result, each of the multiple pixels 11 outputs a signal based on incident light.

[0017] Each row of the pixel array 10 has scan lines 13A, 13B, 13C, 14, and 15 extending in the row direction. Each of the scan lines 13A, 13B, 13C, 14, and 15 is connected to a plurality of pixels 11 arranged in the row direction, forming a common scan line for these pixels 11. The scan lines 13A, 13B, 13C, 14, and 15 are connected to the vertical scanning circuit 20.

[0018] Each column of the pixel array 10 has a signal line 12 that extends in the direction of the column. The signal line 12 is connected to multiple pixels 11 arranged in the direction of the column, and forms a common signal line for these pixels 11. The signal line 12 is connected to the column circuit 30 and a current source (not shown) that supplies drive current to the signal line.

[0019] The vertical scanning circuit 20, column circuit 30, horizontal scanning circuit 40, output circuit 50, and control circuit 60 constitute the drive circuit section that controls the driving of the pixel array 10. In Figure 1, the drive circuit section is arranged around the pixel array 10. However, the position in which the drive circuit section is arranged is not limited to this. For example, if the photoelectric conversion device of this embodiment is a stacked type having a structure in which multiple substrates are stacked, the drive circuit section may be arranged in a region that overlaps with the pixel array 10 in a plan view. In this specification, a plan view refers to viewing a surface of the substrate including the photoelectric conversion section that is parallel to the light incident surface, from the direction of the normal to the surface parallel to the light incident surface.

[0020] The vertical scanning circuit 20 is a scanning circuit that includes logic circuits such as a shift register, gate circuit, and buffer circuit. Based on a vertical synchronization signal, a horizontal synchronization signal, a clock signal, etc., the vertical scanning circuit 20 supplies control signals to the pixels 11 via scan lines 13A, 13B, 13C, 14, and 15. As a result, the vertical scanning circuit 20 performs scanning that causes the pixels 11 to sequentially output signals row by row. The vertical scanning circuit 20 also controls the charge accumulation period in the pixels 11.

[0021] The column circuit 30 includes an amplification circuit, a signal holding circuit, etc. The column circuit 30 performs predetermined processing (e.g., noise reduction, signal amplification, etc.) on the electrical signals input from the pixels 11 of each column via the signal lines 12, for each column. The column circuit 30 outputs the processed signals to the output circuit 50 sequentially for each column, in accordance with the control of the horizontal scanning circuit 40.

[0022] The horizontal scanning circuit 40 is a scanning circuit that includes logic circuits such as a shift register, a gate circuit, and a buffer circuit. The horizontal scanning circuit 40 supplies control signals to the column circuit 30 to sequentially output the processed signals from the column circuit 30 to the output circuit 50. The output circuit 50 outputs the signals input from the column circuit 30 in a predetermined format to an external storage device or signal processing device of the photoelectric converter 1.

[0023] Figure 2 is a circuit diagram of the pixel 11 according to this embodiment. As shown in Figure 2, the pixel 11 includes a photoelectric conversion unit PDA, PDB, PDC, transfer transistors M1A, M1B, M1C, reset transistor M2, amplification transistor M3, and selection transistor M4.

[0024] The photoelectric conversion units PDA, PDB, and PDC are, for example, photodiodes. The anodes of the photoelectric conversion units PDA, PDB, and PDC are connected to the ground node. The cathodes of the photoelectric conversion units PDA, PDB, and PDC are connected to the sources of the transfer transistors M1A, M1B, and M1C, respectively. The drains of the transfer transistors M1A, M1B, and M1C are connected to the source of the reset transistor M2 and the gate of the amplification transistor M3. The node to which the drains of the transfer transistors M1A, M1B, and M1C, the source of the reset transistor M2, and the gate of the amplification transistor M3 are connected is the floating diffusion FD. The floating diffusion FD contains a capacitive component (floating diffusion capacitance) and functions as a charge holder. The floating diffusion capacitance includes the parasitic capacitance of the electrical path from the transfer transistors M1A, M1B, and M1C through the floating diffusion FD to the amplification transistor M3. Figure 2 shows this floating diffusion capacitance equivalently represented by the circuit symbol of the capacitive element.

[0025] The drains of reset transistor M2 and amplifier transistor M3 are connected to a power supply voltage node to which voltage VDD is supplied. The source of amplifier transistor M3 is connected to the drain of selection transistor M4. The source of selection transistor M4 is connected to signal line 12. A current source (not shown) is connected to signal line 12. This current source may be a current source with a switchable current value or a constant current source with a constant current value.

[0026] The gates of transfer transistors M1A, M1B, and M1C are connected to scan lines 13A, 13B, and 13C, respectively. The gate of reset transistor M2 is connected to scan line 14. The gate of selection transistor M4 is connected to scan line 15. With this configuration, control signals from the vertical scanning circuit 20 are input to the gates of transfer transistors M1A, M1B, M1C, reset transistor M2, and selection transistor M4. Multiple pixels 11 in the same row are connected to a common signal line and are controlled simultaneously by a common control signal.

[0027] In this embodiment, each transistor constituting the pixel 11 is assumed to be an N-type MOS transistor. Therefore, when a high-level control signal is supplied from the vertical scanning circuit 20, the corresponding transistor turns on. Conversely, when a low-level control signal is supplied from the vertical scanning circuit 20, the corresponding transistor turns off. Furthermore, the names of the source and drain of a MOS transistor may differ depending on the conductivity type of the transistor or the function of interest. Some or all of the source and drain names used in this embodiment may also be referred to by the reverse names.

[0028] The photoelectric conversion units PDA, PDB, and PDC convert incident light into an amount of charge corresponding to the amount of light (photoelectric conversion). When the transfer transistor M1A (first transfer transistor) is turned on, it transfers the charge held by the photoelectric conversion unit PDA (first photoelectric conversion unit) to the floating diffusion FD. When the transfer transistor M1B (second transfer transistor) is turned on, it transfers the charge held by the photoelectric conversion unit PDB (second photoelectric conversion unit) to the floating diffusion FD. When the transfer transistor M1C (third transfer transistor) is turned on, it transfers the charge held by the photoelectric conversion unit PDC (third photoelectric conversion unit) to the floating diffusion FD. The charges transferred from the photoelectric conversion units PDA, PDB, and PDC are held in the capacitance of the floating diffusion FD (floating diffusion capacitance). As a result, the floating diffusion capacitor (FD) becomes potential corresponding to the amount of charge transferred from the photoelectric conversion units PDA, PDB, and PDC through charge-voltage conversion by the floating diffusion capacitance.

[0029] The select transistor M4, when turned on, connects the amplifier transistor M3 to the signal line 12. The amplifier transistor M3 is configured such that a voltage VDD is supplied to its drain and a bias current is supplied to its source from a current source via the select transistor M4, forming an amplification section (source follower circuit) with its gate as the input node. As a result, the amplifier transistor M3 outputs a signal based on the potential of the floating diffusion FD to the signal line 12 via the select transistor M4. In this sense, the amplifier transistor M3 and the select transistor M4 are output sections that output a pixel signal corresponding to the amount of charge held in the floating diffusion FD.

[0030] The reset transistor M2 has the function of resetting the floating diffusion FD by controlling the supply of voltage (voltage VDD) to the floating diffusion FD. When the reset transistor M2 is turned on, it resets the floating diffusion FD to a voltage corresponding to voltage VDD.

[0031] Figures 3(a) and 3(b) are schematic plan views of the pixel 11 according to this embodiment. Figure 3(a) schematically shows the arrangement of the photoelectric conversion unit PDA, PDB, PDC, floating diffusion FD, and each transistor in a plan view. In Figure 3(a), the regions labeled "PDA," "PDB," and "PDC" indicate the regions where the semiconductor regions of the photodiodes constituting the photoelectric conversion unit PDA, PDB, and PDC are formed. In Figure 3(a), the region labeled "FD" indicates the region where the semiconductor region constituting the floating diffusion FD is formed. In Figure 3(a), the regions labeled "M1A," "M1B," and "M1C" indicate the regions where the gate electrodes of the transfer transistors M1A, M1B, and M1C are located. The dashed line labeled "ML" indicates the position where the microlens ML, which guides incident light to the photoelectric conversion unit PDA, PDB, and PDC, is located. Thus, the microlens ML is commonly installed in the three photoelectric conversion units PDA, PDB, and PDC.

[0032] As shown in Figure 3(a), the area of ​​the photoelectric conversion unit PDC is smaller than the area of ​​both the photoelectric conversion unit PDA and the photoelectric conversion unit PDB. As a result, the sensitivity of the photoelectric conversion unit PDC is lower than that of both the photoelectric conversion unit PDA and the photoelectric conversion unit PDB. Therefore, the photoelectric conversion device 1 of this embodiment can output a signal based on the charge accumulated in the highly sensitive photoelectric conversion unit PDA and PDB, and a signal based on the charge accumulated in the less sensitive photoelectric conversion unit PDC. By performing signal processing using these two types of signals, a high dynamic range can be achieved. For example, a high dynamic range image can be generated by combining these two types of signals. Furthermore, due to the area relationship described above, the saturation charge amount of the photoelectric conversion unit PDC is less than that of both the saturation charge amount of the photoelectric conversion unit PDA and the saturation charge amount of the photoelectric conversion unit PDB.

[0033] Furthermore, the photoelectric conversion unit PDA and the photoelectric conversion unit PDB are arranged to be approximately symmetrical with respect to the line segment A-A' along direction D2 (second direction). In other words, the photoelectric conversion unit PDA and the photoelectric conversion unit PDB are arranged to be aligned in direction D1 (first direction). As a result, the photoelectric conversion device 1 of this embodiment can output a signal based on the charge accumulated in the photoelectric conversion unit PDA and a signal based on the charge accumulated in the photoelectric conversion unit PDB. By performing signal processing using these two types of signals, it is possible to detect the phase difference in direction D1. For example, distance measurement can be performed based on the phase difference of these two types of signals.

[0034] Figure 3(b) shows a region R1 including the photoelectric converter PDA and the photoelectric converter PDB in the same schematic planar view as Figure 3(a). The photoelectric converter PDC is positioned along a part of the outer periphery of region R1. This makes it possible to position the transfer transistors M1A, M1B, M1C and the floating diffusion FD in the peripheral area of ​​the pixel 11. Furthermore, in direction D2, which is perpendicular to direction D1, the centroid position of the photoelectric converter PDC is different from that of both the centroid position of the photoelectric converter PDA and the centroid position of the photoelectric converter PDB. As a result, the amount of light incident on the transfer transistors M1A, M1B, M1C or the floating diffusion FD is reduced compared to a configuration in which they are positioned near the center of the pixel 11. Therefore, signal loss caused by light incident on the transfer transistors M1A, M1B, M1C or the floating diffusion FD can be reduced. The centroid of the photoelectric conversion section is the geometric center of the planar shape of the semiconductor region that constitutes the photoelectric conversion section.

[0035] Figure 4 is a schematic cross-sectional view of a pixel 11 according to this embodiment. Figure 4 schematically shows the cross-section between B and B' in Figure 3. In the semiconductor substrate 100 on which the pixel 11 is formed, the side on which the wiring layer 120 containing scan lines 13A, 13B, 13C, 14, 15, etc. is arranged (the upper side in Figure 4) is defined as the first surface F1. The side opposite to the first surface F1 (the lower side in Figure 4) is defined as the second surface F2. In this embodiment, incident light is assumed to be incident from the side of the first surface F1. In this embodiment, the depth direction refers to the direction from the first surface to the second surface. Although the microlens ML is not shown in Figure 4, the microlens ML is located on top of the wiring layer 120, that is, on the side of the first surface F1 of the semiconductor substrate 100.

[0036] Inside the semiconductor substrate 100 are P-type semiconductor regions 101, 103, 104, 105, 106 and N-type semiconductor regions 102A, 102B, 102C. The P-type semiconductor region 101 is a well region. The N-type semiconductor regions 102A, 102B, 102C (first semiconductor region) are located at a shallower position (closer to the first surface F1) than the P-type semiconductor region 101 (second semiconductor region). Each of the N-type semiconductor regions 102A, 102B, 102C and the P-type semiconductor region 101 constitute a photodiode. The N-type semiconductor region 102A and the P-type semiconductor region 101 correspond to a photoelectric conversion unit PDA. The N-type semiconductor region 102B and the P-type semiconductor region 101 correspond to a photoelectric conversion unit PDB. The N-type semiconductor region 102C and the P-type semiconductor region 101 correspond to a photoelectric conversion unit PDC.

[0037] The P-type semiconductor region 103 is formed in contact with the first surface F1 and has a higher impurity concentration than other P-type semiconductor regions. The P-type semiconductor region 103 reduces the influence of dark electrons generated on the first surface.

[0038] The P-type semiconductor region 104 is a separation region (first separation region) formed between the N-type semiconductor region 102A and the N-type semiconductor region 102B. The P-type semiconductor region 105 is a separation region (second separation region) formed between the N-type semiconductor region 102A and the N-type semiconductor region 102C. The P-type semiconductor region 106 is a separation region (third separation region) formed between the N-type semiconductor region 102B and the N-type semiconductor region 102C. The impurity concentration in the P-type semiconductor region 105 is higher than that of the P-type semiconductor region 104. Also, the impurity concentration in the P-type semiconductor region 106 is higher than that of the P-type semiconductor region 104. This makes it difficult for charge to flow from the photoelectric conversion unit PDA or photoelectric conversion unit PDB to the photoelectric conversion unit PDC in situations where a lot of charge is generated in the highly sensitive photoelectric conversion unit PDA and PDB, such as when imaging a high-brightness subject.

[0039] Furthermore, the bottom surface of the N-type semiconductor region 102C is formed at a shallower position compared to the bottom surfaces of the N-type semiconductor region 102A and the N-type semiconductor region 102B. In other words, the thickness of the N-type semiconductor region 102C is thinner than the thickness of both the N-type semiconductor region 102A and the N-type semiconductor region 102B. This makes it difficult for charge generated in the deeper parts of the semiconductor substrate 100 to flow into the N-type semiconductor region 102C. This further reduces the sensitivity of the photoelectric conversion unit PDC.

[0040] In the photoelectric converter 1 of this embodiment, the photoelectric conversion unit PDC is arranged along a part of the outer periphery of region R1, which includes the photoelectric conversion unit PDA and the photoelectric conversion unit PDB. As a result, the transfer transistors M1A, M1B, M1C and the floating diffusion FD are arranged in the peripheral area of ​​the pixel 11, reducing the loss caused by light incident on them. Therefore, according to this embodiment, a photoelectric converter 1 with reduced signal loss is provided.

[0041] [Second Embodiment] The second embodiment will be described with reference to Figures 5 to 8. In this embodiment, the number of photoelectric conversion units has increased from 3 to 4 compared to the pixel 11 configuration of the first embodiment. The following will mainly describe the differences from the first embodiment, but elements common to the first embodiment may be omitted or simplified in their explanation.

[0042] Figure 5 is a block diagram showing the schematic configuration of the photoelectric converter 1 according to this embodiment. In this embodiment, a scan line 13D is further arranged. The scan line 13D is connected to a plurality of pixels 11 arranged in the row direction and forms a common scan line for these pixels 11. The scan line 13D is connected to the vertical scanning circuit 20.

[0043] Figure 6 is a circuit diagram of the pixel 11 according to this embodiment. As shown in Figure 6, the pixel 11 further includes a photoelectric conversion unit PDD and a transfer transistor M1D in addition to the configuration shown in Figure 2.

[0044] The photoelectric converter PDD is, for example, a photodiode. The anode of the photoelectric converter PDD is connected to the ground node. The cathode of the photoelectric converter PDD is connected to the source of the transfer transistor M1D. The drain of the transfer transistor M1D is connected to the node of the floating diffusion FD. The scan line 13D is connected to the gate of the transfer transistor M1D. A control signal from the vertical scanning circuit 20 is input to the gate of the transfer transistor M1D. The transfer transistor M1D (fourth transfer transistor) turns on based on the control signal, thereby transferring the charge held by the photoelectric converter PDD (fourth photoelectric converter) to the floating diffusion FD.

[0045] Figures 7(a) and 7(b) are schematic plan views of the pixel 11 according to this embodiment. Figure 7(a) schematically shows the arrangement of the photoelectric conversion units PDA, PDB, PDC, PDD, floating diffusion FD, and each transistor in a plan view. The area labeled "PDD" indicates the area where the semiconductor region of the photodiode constituting the photoelectric conversion unit PDD is formed. The area labeled "M1D" indicates the area where the gate electrode of the transfer transistor M1D is located. The microlens ML is commonly provided for the four photoelectric conversion units PDA, PDB, PDC, and PDD. Three vias V1 are provided for each of the three floating diffusion FDs. The vias V1 are connected to wiring provided on the wiring layer 120, and the three floating diffusion FDs are electrically connected to each other via this wiring.

[0046] As shown in Figure 7(a), the area of ​​the photoelectric conversion units PDC and PDD is smaller than the area of ​​both the photoelectric conversion unit PDA and the photoelectric conversion unit PDB. As a result, the sensitivity of the photoelectric conversion units PDC and PDD is lower than the sensitivity of both the photoelectric conversion unit PDA and the photoelectric conversion unit PDB. Therefore, the photoelectric conversion device 1 of this embodiment can output signals based on the charge accumulated in the highly sensitive photoelectric conversion units PDA and PDB, and signals based on the charge accumulated in the less sensitive photoelectric conversion units PDC and PDD. By performing signal processing using these two types of signals, a high dynamic range can be achieved, similar to the first embodiment. Furthermore, due to the area relationship described above, the saturation charge amount of the photoelectric conversion units PDC and PDD is less than the saturation charge amount of both the photoelectric conversion unit PDA and the saturation charge amount of the photoelectric conversion unit PDB.

[0047] Furthermore, the photoelectric conversion units PDA and PDB are arranged to be approximately symmetrical with respect to the line segment A-A' along direction D2. In other words, the photoelectric conversion units PDA and PDB are arranged to be aligned in direction D1. In addition, the photoelectric conversion units PDC and PDD are also arranged to be approximately symmetrical with respect to the line segment A-A' along direction D2. In other words, the photoelectric conversion units PDC and PDD are also arranged to be aligned in direction D1. Similar to the first embodiment, phase difference detection can be performed using two signals based on the photoelectric conversion units PDA and PDB. In this embodiment, phase difference detection can also be performed using two signals based on the photoelectric conversion units PDC and PDD. In this embodiment, even in situations where charge saturation may occur in the photoelectric conversion unit PDA and photoelectric conversion unit PDB, such as when imaging a high-brightness subject, phase difference detection can be performed by using two signals based on the less sensitive photoelectric conversion unit PDC and photoelectric conversion unit PDD. This enables more accurate phase difference detection even when the subject is high-brightness.

[0048] Figure 7(b) shows a region R2 including the photoelectric converter PDA and photoelectric converter PDB in the same schematic planar view as Figure 7(a). The photoelectric converters PDC and PDD are arranged along a part of the outer periphery of region R2. This makes it possible to arrange the transfer transistors M1A, M1B, M1C, M1D and the floating diffusion FD in the peripheral area of ​​the pixel 11. Furthermore, in direction D1, the distance between the centroid of the photoelectric converter PDC and the centroid of the photoelectric converter PDB is greater than the distance between the centroid of the photoelectric converter PDC and the centroid of the photoelectric converter PDA. As a result, the amount of light incident on the transfer transistors M1A, M1B, M1C, M1D or the floating diffusion FD is reduced compared to a configuration in which they are located near the center of the pixel 11. Therefore, signal loss caused by light incident on the transfer transistors M1A, M1B, M1C, M1D, or floating diffusion FD can be reduced.

[0049] Figure 8 is a schematic cross-sectional view of a pixel 11 according to this embodiment. Figure 8 schematically shows the cross-section between C and C' in Figure 7. Inside the semiconductor substrate 100 are P-type semiconductor regions 101, 103, 104, 105, 107 and N-type semiconductor regions 102A, 102B, 102C, 102D. The N-type semiconductor region 102D is located at a shallower position (closer to the first surface F1) than the P-type semiconductor region 101. The N-type semiconductor region 102D and the P-type semiconductor region 101 constitute a photodiode. The N-type semiconductor region 102D and the P-type semiconductor region 101 correspond to the photoelectric conversion unit PDD. On the side of the first surface F1 of the semiconductor substrate 100, a wiring layer 120 and a microlens ML are arranged.

[0050] The P-type semiconductor region 107 is a separation region formed between the N-type semiconductor region 102B and the N-type semiconductor region 102D. The impurity concentration in the P-type semiconductor region 107 is higher than that in the P-type semiconductor region 104. In situations where a large amount of charge is generated in the highly sensitive photoelectric conversion units PDA and PDB, such as when imaging a high-brightness subject, it is possible to reduce the inflow of charge from the photoelectric conversion unit PDA to the photoelectric conversion unit PDC, and from the photoelectric conversion unit PDB to the photoelectric conversion unit PDD.

[0051] Furthermore, the bottom surfaces of the N-type semiconductor regions 102C and 102D are formed at a shallower position compared to the bottom surfaces of the N-type semiconductor region 102A and the N-type semiconductor region 102B. In other words, the thickness of the N-type semiconductor regions 102C and 102D is thinner than the thickness of both the N-type semiconductor region 102A and the N-type semiconductor region 102B. This makes it difficult for charge generated in the deeper parts of the semiconductor substrate 100 to flow into the N-type semiconductor regions 102C and 102D. This further reduces the sensitivity of the photoelectric conversion units PDC and PDD.

[0052] In the photoelectric converter 1 of this embodiment, the photoelectric conversion units PDC and PDD are arranged along a portion of the outer periphery of region R2, which includes the photoelectric conversion units PDA and PDB. As a result, the transfer transistors M1A, M1B, M1C, M1D and the floating diffusion FD are arranged in the peripheral area of ​​the pixel 11, reducing the loss caused by light incident on them. Therefore, according to this embodiment, a photoelectric converter 1 with reduced signal loss is provided.

[0053] [Third Embodiment] The third embodiment will be described with reference to Figure 9. In this embodiment, the transfer transistors M1A and M1B in the pixel 11 of the second embodiment are each connected in parallel. The following will mainly describe the differences from the second embodiment, but the explanation of elements common to the second embodiment may be omitted or simplified.

[0054] Figure 9 is a schematic plan view of the pixel 11 according to this embodiment. As shown in Figure 9, in this embodiment, the transfer transistor M1A in the second embodiment is connected in parallel with two transfer transistors M1A-1 and M1A-2. The transfer transistors M1A-1 and M1A-2 are arranged along the end of the photoelectric conversion unit PDA. The gate electrodes of the transfer transistors M1A-1 and M1A-2 are short-circuited via via V2 and connecting wiring WA. Similarly, in this embodiment, the transfer transistor M1B in the second embodiment is connected in parallel with two transfer transistors M1B-1 and M1B-2. The transfer transistors M1B-1 and M1B-2 are arranged along the end of the photoelectric conversion unit PDB. The gate electrodes of the transfer transistors M1B-1 and M1B-2 are short-circuited via via V2 and connecting wiring WB.

[0055] In this embodiment, the transfer transistors are connected in parallel. This effectively widens the gate width of the transfer transistors. Therefore, compared to the configuration of the second embodiment, the charge transfer from the photoelectric conversion units PDA and PDB to the floating diffusion FD is accelerated. Thus, this embodiment provides a photoelectric conversion device 1 that has the effects described in the second embodiment, in addition to being able to accelerate charge transfer. In this embodiment, a configuration in which two transfer transistors are connected in parallel is adopted, but three or more transfer transistors may be connected in parallel.

[0056] [Fourth Embodiment] The fourth embodiment will be described with reference to Figures 10(a) and 10(b). In this embodiment, the transfer transistors M1C and M1D and the photoelectric conversion units PDC and PDD in the pixel 11 of the second embodiment are each connected in parallel. The following will mainly describe the differences from the second embodiment, but the explanation of elements common to the second embodiment may be omitted or simplified.

[0057] Figure 10(a) is a schematic plan view of the pixel 11 according to this embodiment. As shown in Figure 10(a), the photoelectric conversion unit PDC in the second embodiment is connected in parallel to two photoelectric conversion units PDC-1 and PDC-2. Also, the transfer transistor M1C in the second embodiment is connected in parallel to two transfer transistors M1C-1 and M1C-2. The gate electrodes of transfer transistors M1C-1 and M1C-2 are short-circuited via via V2 and connecting wiring WC. Similarly, the photoelectric conversion unit PDD in the second embodiment is connected in parallel to two photoelectric conversion units PDD-1 and PDD-2. Also, the transfer transistor M1D in the second embodiment is connected in parallel to two transfer transistors M1D-1 and M1D-2. The gate electrodes of transfer transistors M1D-1 and M1D-2 are short-circuited via via V2 and connecting wiring WD.

[0058] As shown in Figure 10(a), the photoelectric conversion unit PDC-1 and the photoelectric conversion unit PDD-2 are arranged to be approximately symmetric with respect to the line segment D-D' along direction D3 (the third direction) between direction D1 and direction D2. In other words, the photoelectric conversion unit PDC-1 and the photoelectric conversion unit PDD-2 are arranged to be aligned in direction D4, which intersects direction D3. Furthermore, the photoelectric conversion unit PDC-2 and the photoelectric conversion unit PDD-1 are arranged to be approximately symmetric with respect to the line segment E-E' along direction D4. In other words, the photoelectric conversion unit PDC-2 and the photoelectric conversion unit PDD-1 are arranged to be aligned in direction D3.

[0059] According to the configuration of this embodiment, compared to the configuration of the second embodiment, light incident into the pixel 11 along direction D3 or direction D4 is more easily incident into the photoelectric conversion units PDC-1, PDC-2, PDD-1, and PDD-2. Therefore, by performing signal processing using signals based on the charge accumulated in the photoelectric conversion units PDC-1, PDC-2, PDD-1, and PDD-2, phase difference detection in direction D3 or direction D4 can be performed.

[0060] Figure 10(b) shows a schematic plan view of the same region R3 as in Figure 10(a), including the photoelectric conversion unit PDA and the photoelectric conversion unit PDB. The photoelectric conversion units PDC-1, PDC-2, PDD-1, and PDD-2 are arranged along a part of the outer periphery of region R3. This makes it possible to arrange the transfer transistors M1A, M1B, M1C-1, M1C-2, M1D-1, M1D-2 and the floating diffusion FD in the peripheral area of ​​the pixel 11. As a result, the amount of light incident on the transfer transistors M1A, M1B, M1C-1, M1C-2, M1D-1, M1D-2 or the floating diffusion FD is reduced compared to a configuration in which they are located near the center of the pixel 11. Therefore, signal loss caused by light incident on the transfer transistors M1A, M1B, M1C-1, M1C-2, M1D-1, M1D-2, or floating diffusion FD can be reduced.

[0061] According to this embodiment, in addition to having the effects described in the second embodiment, a photoelectric converter 1 is provided that can perform phase difference detection in direction D3 or direction D4.

[0062] [Fifth Embodiment] The fifth embodiment will be described with reference to Figures 11(a) and 11(b). In this embodiment, the photoelectric conversion unit PDC and the photoelectric conversion unit PDD of the second embodiment are modified so that they are aligned in direction D2. The following will mainly describe the differences from the second embodiment, but the explanation of elements common to the second embodiment may be omitted or simplified.

[0063] Figure 11(a) is a schematic plan view of the pixel 11 according to this embodiment. As shown in Figure 11(a), the photoelectric conversion unit PDC and the photoelectric conversion unit PDD are arranged to be approximately symmetric with respect to the line segment F-F' along direction D1. In other words, the photoelectric conversion unit PDC and the photoelectric conversion unit PDD are arranged to be aligned in direction D2. According to this embodiment, phase difference detection in direction D2 can be performed using two signals based on the photoelectric conversion unit PDC and the photoelectric conversion unit PDD.

[0064] Figure 11(b) shows a schematic plan view of the same region R4 as in Figure 11(a), including the photoelectric converter PDA and the photoelectric converter PDB. The photoelectric converters PDC and PDD are arranged along a part of the outer periphery of region R4. This makes it possible to arrange the transfer transistors M1A, M1B, M1C, M1D and the floating diffusion FD in the peripheral area of ​​the pixel 11. As a result, the amount of light incident on the transfer transistors M1A, M1B, M1C, M1D or the floating diffusion FD is reduced compared to a configuration in which they are located near the center of the pixel 11. Therefore, signal loss caused by light incident on the transfer transistors M1A, M1B, M1C, M1D or the floating diffusion FD can be reduced.

[0065] According to this embodiment, in addition to having the effects described in the second embodiment, a photoelectric converter 1 is provided that can perform phase difference detection in direction D2.

[0066] [Sixth Embodiment] The sixth embodiment will be described with reference to Figures 12, 13(a), and 13(b). In this embodiment, one floating diffusion FD in pixel 11 is shared by eight photoelectric conversion units. The following will mainly describe the differences from the fifth embodiment, but elements common to the fifth embodiment may be omitted or simplified in their explanation.

[0067] Figure 12 is a circuit diagram of the pixel 11 according to this embodiment. As shown in Figure 12, the pixel 11 has two photoelectric conversion unit groups 16 and 17. The photoelectric conversion unit group 16 has photoelectric conversion units PDA, PDB, PDC, PDD and transfer transistors M1A, M1B, M1C, and M1D. These configurations are the same as those shown in Figure 6, so their explanation is omitted.

[0068] The photoelectric conversion unit group 17 includes photoelectric conversion units PDE, PDF, PDG, PDH and transfer transistors M1E, M1F, M1G, M1H. The photoelectric conversion units PDE, PDF, PDG, PDH are, for example, photodiodes. The anodes of the photoelectric conversion units PDE, PDF, PDG, PDH are connected to the ground node. The cathodes of the photoelectric conversion units PDE, PDF, PDG, PDH are connected to the sources of the transfer transistors M1E, M1F, M1G, M1H, respectively. The drains of the transfer transistors M1E, M1F, M1G, M1H are connected to the node of the floating diffusion FD.

[0069] The other configurations are generally the same as those in Figure 6, so their explanation will be omitted. Thus, in this embodiment, the two photoelectric conversion groups 16 and 17 share one floating diffusion FD.

[0070] Figure 13(a) is a schematic plan view of the pixel 11 according to this embodiment. As shown in Figure 13(a), the arrangement of the photoelectric conversion unit group 16 is generally the same as that shown in Figure 11(a), except in the vicinity of the floating diffusion FD. The arrangement of the photoelectric conversion unit group 17 is a mirror image of the photoelectric conversion unit group 16 with respect to the boundary line along the direction D1 between the photoelectric conversion unit group 16 and the photoelectric conversion unit group 17. That is, the photoelectric conversion unit group 16 and the photoelectric conversion unit group 17 are approximately symmetric with respect to the boundary line along the direction D1 between the photoelectric conversion unit group 16 and the photoelectric conversion unit group 17. Near the boundary between the photoelectric conversion unit group 16 and the photoelectric conversion unit group 17, the semiconductor region of the floating diffusion FD located on that boundary line is shared by the two photoelectric conversion unit groups 16 and 17.

[0071] Figure 13(b) is a comparative example of this embodiment, showing a configuration in which two pixels 11 of the fifth embodiment are arranged adjacent to each other along direction D1. The two pixels 11 are in a positional relationship of parallel translation.

[0072] In the configuration shown in Figure 13(b), an element isolation region is positioned between two floating diffusion FDs on the line segment G-G' along direction D2. In contrast, in the configuration shown in Figure 13(a) of this embodiment, one floating diffusion FD is positioned between the line segment H-H' along direction D2, and no element isolation region is positioned between them. Therefore, compared to the configuration shown in Figure 13(b), the configuration shown in Figure 13(a) of this embodiment allows for a longer length of the photoelectric conversion units PDA, PDB, PDE, and PDF in direction D2, and increases the area of ​​the photoelectric conversion units PDA, PDB, PDE, and PDF. Consequently, the sensitivity of the photoelectric conversion units PDA, PDB, PDE, and PDF can be further improved.

[0073] According to this embodiment, in addition to having the effects described in the fifth embodiment, a photoelectric converter 1 with improved sensitivity is provided.

[0074] [Seventh Embodiment] The seventh embodiment will be described with reference to Figure 14. This embodiment is a configuration in which the configuration of the fifth embodiment has been modified to a back-illuminated type. The following will mainly describe the differences from the fifth embodiment, but the explanation of elements common to the fifth embodiment may be omitted or simplified.

[0075] In this embodiment, the planar structure of the pixel 11 is the same as that of Figure 11(a) in the fifth embodiment. Figure 14 is a schematic cross-sectional view of the pixel 11 according to this embodiment. Figure 14 schematically shows the cross-section between F-F' in Figure 11(a). Inside the semiconductor substrate 100 are P-type semiconductor regions 101, 103, 104, N-type semiconductor regions 102A, 102B, and an element isolation region 108. The element isolation region 108 is formed, for example, by DTI (Deep Trench Isolation) isolation, P-type diffusion layer isolation, etc.

[0076] A wiring layer 120 is arranged on the first side of the semiconductor substrate 100. An insulating layer 130, which may include a planarization layer, a color filter, etc., is arranged on the second side of the semiconductor substrate 100. A microlens ML is arranged on the insulating layer 130. In other words, the photoelectric conversion device 1 of this embodiment has a back-illuminated structure in which light is incident from the side opposite to the wiring layer 120. Since the incident light is incident on the photoelectric conversion unit without being reflected by the wiring in the wiring layer 120, the sensitivity of the photoelectric conversion unit can be improved.

[0077] According to this embodiment, in addition to having the effects described in the fifth embodiment, a photoelectric converter 1 with improved sensitivity is provided.

[0078] [Eighth Embodiment] The photoelectric converter in the above-described embodiment is applicable to various devices. Examples of such devices include digital still cameras, digital camcorders, camera heads, photocopiers, fax machines, mobile phones, in-vehicle cameras, observation satellites, and surveillance cameras. Figure 15 shows a block diagram of a digital still camera as an example of such a device.

[0079] The device 70 shown in Figure 15 includes a barrier 706, a lens 702, an aperture 704, and an imaging device 700 (an example of a photoelectric converter). The device 70 further includes a signal processing unit (processing unit) 708, a timing generation unit 720, an overall control / calculation unit 718 (control device), a memory unit 710 (storage device), a recording medium control I / F unit 716, a recording medium 714, and an external I / F unit 712. At least one of the barrier 706, lens 702, and aperture 704 is an optical device corresponding to the device. The barrier 706 protects the lens 702, and the lens 702 forms an optical image of the subject on the imaging device 700. The aperture 704 varies the amount of light passing through the lens 702. The imaging device 700 is configured as in the above-described embodiment and converts the optical image formed by the lens 702 into image data (image signal). The signal processing unit 708 performs various corrections, data compression, etc., on the imaging data output from the imaging device 700. The timing generation unit 720 outputs various timing signals to the imaging device 700 and the signal processing unit 708. The overall control / calculation unit 718 controls the entire digital still camera, and the memory unit 710 temporarily stores image data. The recording medium control I / F unit 716 is an interface for recording or reading image data to or from the recording medium 714, which is a removable recording medium such as a semiconductor memory for recording or reading imaging data. The external I / F unit 712 is an interface for communicating with an external computer or the like. Timing signals and the like may be input from outside the device. Furthermore, the device 70 may also include a display device (monitor, electronic viewfinder, etc.) that displays information obtained from the photoelectric converter. The device includes at least a photoelectric converter. Furthermore, the device 70 includes at least one of an optical device, a control device, a processing device, a display device, a storage device, and a mechanical device that operates based on information obtained from the photoelectric converter. The mechanical device is a movable part (for example, a robot arm) that operates in response to signals from the photoelectric converter.

[0080] Each pixel may include multiple photoelectric conversion units (a first photoelectric conversion unit and a second photoelectric conversion unit). The signal processing unit 708 may be configured to process a pixel signal based on the charge generated by the first photoelectric conversion unit and a pixel signal based on the charge generated by the second photoelectric conversion unit to acquire distance information from the imaging device 700 to the subject.

[0081] [Ninth Embodiment] Figures 16(a) and 16(b) are block diagrams of the equipment related to the in-vehicle camera in this embodiment. Equipment 80 includes an imaging device 800 (an example of a photoelectric converter) as described above, and a signal processing device (processing device) that processes signals from the imaging device 800. Equipment 80 includes an image processing unit 801 that performs image processing on a plurality of image data acquired by the imaging device 800, and a parallax calculation unit 802 that calculates parallax (phase difference of parallax images) from a plurality of image data acquired by Equipment 80. Equipment 80 also includes a distance measurement unit 803 that calculates the distance to an object based on the calculated parallax, and a collision determination unit 804 that determines whether or not there is a possibility of collision based on the calculated distance. Here, the parallax calculation unit 802 and the distance measurement unit 803 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 804 may use any of this distance information to determine the possibility of collision. The means for acquiring distance information 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.

[0082] Device 80 is connected to a vehicle information acquisition device 810 and can acquire vehicle information such as vehicle speed, yaw rate, and steering angle. Device 80 is also connected to a control ECU 820, which is a control device that outputs a control signal to generate braking force on the vehicle based on the collision determination result of the collision determination unit 804. Furthermore, device 80 is connected to a warning device 830 that issues a warning to the driver based on the collision determination result of the collision determination unit 804. For example, if the collision determination result of the collision determination unit 804 indicates a high probability of collision, the control ECU 820 performs vehicle control to avoid a collision or mitigate damage by applying the brakes, releasing the accelerator, or suppressing engine output. The warning device 830 warns the user by sounding an alarm, displaying warning information on a screen such as a car navigation system, or vibrating the seatbelt or steering wheel. As described above, device 80 functions as a control means that controls the actions that control the vehicle.

[0083] In this embodiment, the equipment 80 images the area around the vehicle, for example, in front of or behind it. Figure 16(b) shows the equipment when imaging the area in front of the vehicle (imaging range 850). The vehicle information acquisition device 810, acting as an imaging control means, sends instructions to the equipment 80 or imaging device 800 to perform the imaging operation. This configuration allows for further improvement of the accuracy of distance measurement.

[0084] The above example described controlling a vehicle to avoid collisions with other vehicles, but it can also be applied to control systems that automatically follow other vehicles, or control systems that automatically stay within their lane. Furthermore, the equipment is not limited to vehicles such as automobiles, but can be applied to mobile objects (mobile devices) such as ships, aircraft, satellites, industrial robots, and consumer robots. In addition, it can be applied not only to mobile objects, but also to a wide range of devices that utilize object recognition or biometric recognition, such as intelligent transportation systems (ITS) and surveillance systems.

[0085] [Modified Embodiment] The present invention is not limited to the embodiments described above and can be modified in various ways. For example, an example in which a part of the configuration of one embodiment is added to another embodiment, or an example in which a part of the configuration of one embodiment is replaced with a part of the configuration of another embodiment, is also an embodiment of the present invention.

[0086] The disclosures in this specification include the complements of the concepts described herein. That is, if this specification contains a statement such as "A is B" (A=B), the specification shall be deemed to disclose or imply "A is not B" (A≠B) even if a statement such as "A is not B" is omitted. This is because the statement "A is B" presupposes that the case where "A is not B" is being considered.

[0087] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by a process in which one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0088] It should be noted that the embodiments described above 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 ways without departing from its technical concept or its main features. [Explanation of symbols]

[0089] 11 pixels FD Floating Diffusion M1A, M1B, M1C Transfer Transistors ML Microlens PDA, PDB, PDC Photoelectric Converter

Claims

1. circuit board and A first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit are each arranged on the substrate and generate an electric charge based on incident light, The substrate is provided with a microlens that is commonly arranged in the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, A floating diffusion arranged on the aforementioned substrate, A first transfer transistor is disposed on the substrate and transfers the charge generated in the first photoelectric conversion unit to the floating diffusion, A second transfer transistor is disposed on the substrate and transfers the charge generated in the second photoelectric conversion unit to the floating diffusion, A third transfer transistor is disposed on the substrate and transfers the charge generated in the third photoelectric conversion unit to the floating diffusion, It has, In a plan view of the substrate, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged to be aligned in the first direction. The sensitivity of the third photoelectric conversion unit is lower than that of the first photoelectric conversion unit and the second photoelectric conversion unit. In the plan view, the third photoelectric conversion unit is arranged along a part of the outer periphery of a region including the first photoelectric conversion unit and the second photoelectric conversion unit. In the plan view, at least a portion of the third photoelectric conversion unit and at least a portion of the floating diffusion are arranged in order along a direction from the center of the microlens toward the outer circumference of the microlens. A photoelectric conversion device characterized by the following features.

2. In the plan view, the area of ​​the third photoelectric conversion unit is smaller than the area of ​​the first photoelectric conversion unit and the area of ​​the second photoelectric conversion unit. The photoelectric conversion device according to feature 1.

3. Each of the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit has a photodiode including a first semiconductor region of a first conductivity type having the same carrier as the signal carrier as the majority carrier, and a second semiconductor region of a second conductivity type different from the first conductivity type. The thickness of the first semiconductor region in the third photoelectric conversion unit is thinner than the thickness of the first semiconductor region in the first photoelectric conversion unit and the thickness of the first semiconductor region in the second photoelectric conversion unit. The photoelectric conversion device according to claim 1 or 2.

4. A first separation unit is disposed on the substrate between the first photoelectric conversion unit and the second photoelectric conversion unit, A second separation unit is disposed on the substrate between the first photoelectric conversion unit and the third photoelectric conversion unit, A third separation unit is disposed on the substrate between the second photoelectric conversion unit and the third photoelectric conversion unit, It further possesses, The impurity concentration in the second separation section is higher than the impurity concentration in the first separation section. The impurity concentration in the third separation section is higher than the impurity concentration in the first separation section. The photoelectric conversion device according to any one of claims 1 to 3.

5. The saturation charge amount of the third photoelectric conversion unit is less than the saturation charge amount of the first photoelectric conversion unit and the saturation charge amount of the second photoelectric conversion unit. The photoelectric conversion device according to any one of claims 1 to 4.

6. In a second direction perpendicular to the first direction, the center of gravity of the third photoelectric conversion unit is different from both the center of gravity of the first photoelectric conversion unit and the center of gravity of the second photoelectric conversion unit. The photoelectric conversion device according to any one of claims 1 to 5.

7. In the first direction, the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the second photoelectric conversion unit is greater than the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the first photoelectric conversion unit. The photoelectric conversion device according to any one of claims 1 to 6.

8. A fourth photoelectric conversion unit is disposed on the substrate and generates an electric charge based on incident light, A fourth transfer transistor is disposed on the substrate and transfers the charge generated in the fourth photoelectric conversion unit to the floating diffusion, It further possesses, The microlenses are commonly arranged in the first photoelectric conversion unit, the second photoelectric conversion unit, the third photoelectric conversion unit, and the fourth photoelectric conversion unit. The photoelectric conversion device according to any one of claims 1 to 7.

9. In the plan view, the third photoelectric conversion unit and the fourth photoelectric conversion unit are arranged to be aligned in the first direction. The photoelectric conversion device according to feature 8.

10. In the aforementioned plan view, the third photoelectric conversion unit and the fourth photoelectric conversion unit are arranged to be aligned in a second direction perpendicular to the first direction. The photoelectric conversion device according to feature 8.

11. In the plan view, the fourth photoelectric conversion unit is arranged along a part of the outer periphery of a region including the first photoelectric conversion unit and the second photoelectric conversion unit. The photoelectric conversion device according to any one of claims 8 to 10.

12. Two of the aforementioned third photoelectric conversion units, Two third transfer transistors, each transferring the charge generated by the two third photoelectric conversion units to the floating diffusion, Two of the aforementioned fourth photoelectric conversion units, Two fourth transfer transistors, each transferring the charge generated by the two fourth photoelectric conversion units to the floating diffusion, A photoelectric conversion device according to any one of claims 8 to 11, characterized by having the following features.

13. One of the two third photoelectric conversion units and one of the two fourth photoelectric conversion units are arranged so as to be aligned in a third direction intersecting the first direction. The photoelectric conversion device according to feature 12.

14. Two of the first transfer transistors connected in parallel, Two of the aforementioned second transfer transistors connected in parallel, A photoelectric conversion device according to any one of claims 1 to 13, characterized by having the following features.

15. The device has a plurality of pixels, each containing the first photoelectric conversion unit, the second photoelectric conversion unit, the third photoelectric conversion unit, the first transfer transistor, the second transfer transistor, and the third transfer transistor, The first transfer transistor, the second transfer transistor, and the third transfer transistor, which are included in two adjacent pixels among the plurality of pixels, transfer charge to a common floating diffusion. In the aforementioned plan view, the common floating diffusion is positioned between the two pixels. The photoelectric conversion device according to any one of claims 1 to 14.

16. The substrate has a first surface and a second surface, Wiring that supplies control signals to be input to the first transfer transistor, the second transfer transistor, and the third transfer transistor is arranged on the first side, The microlens is positioned on the side of the second surface. The photoelectric conversion device according to any one of claims 1 to 15.

17. circuit board and A first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit are each arranged on the substrate and generate an electric charge based on incident light, The substrate is provided with a microlens that is commonly arranged in the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, A floating diffusion is disposed on the substrate and to which charge is transferred from the first photoelectric conversion unit, the second photoelectric conversion unit and the third photoelectric conversion unit, It has, The saturation charge amount of the third photoelectric conversion unit is less than the saturation charge amount of the first photoelectric conversion unit and the saturation charge amount of the second photoelectric conversion unit. In a plan view of the substrate, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged to be aligned in the first direction. In a second direction perpendicular to the first direction, the center of gravity of the third photoelectric conversion unit is different from both the center of gravity of the first photoelectric conversion unit and the center of gravity of the second photoelectric conversion unit. In the plan view, at least a portion of the third photoelectric conversion unit and at least a portion of the floating diffusion are arranged in order along a direction from the center of the microlens toward the outer circumference of the microlens. A photoelectric conversion device characterized by the following features.

18. circuit board and A first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit are each arranged on the substrate and generate an electric charge based on incident light, The substrate is provided with a microlens that is commonly arranged in the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, A floating diffusion is disposed on the substrate and to which charge is transferred from the first photoelectric conversion unit, the second photoelectric conversion unit and the third photoelectric conversion unit, It has, The saturation charge amount of the third photoelectric conversion unit is less than the saturation charge amount of the first photoelectric conversion unit and the saturation charge amount of the second photoelectric conversion unit. In a plan view of the substrate, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged to be aligned in the first direction. In the first direction, the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the second photoelectric conversion unit is greater than the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the first photoelectric conversion unit. In the plan view, at least a portion of the third photoelectric conversion unit and at least a portion of the floating diffusion are arranged in order along a direction from the center of the microlens toward the outer circumference of the microlens. A photoelectric conversion device characterized by the following features.

19. In the plan view, the area of ​​the third photoelectric conversion unit is smaller than the area of ​​the first photoelectric conversion unit and the area of ​​the second photoelectric conversion unit. The photoelectric conversion device according to claim 17 or 18.

20. Each of the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit has a photodiode including a first semiconductor region of a first conductivity type having the same carrier as the signal carrier as the majority carrier, and a second semiconductor region of a second conductivity type different from the first conductivity type. The thickness of the first semiconductor region in the third photoelectric conversion unit is thinner than the thickness of the first semiconductor region in the first photoelectric conversion unit and the thickness of the first semiconductor region in the second photoelectric conversion unit. The photoelectric conversion device according to any one of claims 17 to 19.

21. A first separation unit is disposed on the substrate between the first photoelectric conversion unit and the second photoelectric conversion unit, A second separation unit is disposed on the substrate between the first photoelectric conversion unit and the third photoelectric conversion unit, A third separation unit is disposed on the substrate between the second photoelectric conversion unit and the third photoelectric conversion unit, It further possesses, The impurity concentration in the second separation section is higher than the impurity concentration in the first separation section. The impurity concentration in the third separation section is higher than the impurity concentration in the first separation section. The photoelectric conversion device according to any one of claims 17 to 20.

22. A substrate and A first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit are each arranged on the substrate and generate an electric charge based on incident light, The substrate is provided with a microlens that is commonly arranged in the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, A floating diffusion arranged on the aforementioned substrate, A first transfer transistor is disposed on the substrate and transfers the charge generated in the first photoelectric conversion unit to the floating diffusion, A second transfer transistor is disposed on the substrate and transfers the charge generated in the second photoelectric conversion unit to the floating diffusion, A third transfer transistor is disposed on the substrate and transfers the charge generated in the third photoelectric conversion unit to the floating diffusion, A first separation unit is disposed on the substrate between the first photoelectric conversion unit and the second photoelectric conversion unit, A second separation unit is disposed on the substrate between the first photoelectric conversion unit and the third photoelectric conversion unit, A third separation unit is disposed on the substrate between the second photoelectric conversion unit and the third photoelectric conversion unit, It has, In a plan view of the substrate, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged to be aligned in the first direction. The sensitivity of the third photoelectric conversion unit is lower than that of the first photoelectric conversion unit and the second photoelectric conversion unit. In the plan view, the third photoelectric conversion unit is arranged along a part of the outer periphery of a region including the first photoelectric conversion unit and the second photoelectric conversion unit. The impurity concentration in the second separation section is higher than the impurity concentration in the first separation section. The impurity concentration in the third separation section is higher than the impurity concentration in the first separation section. A photoelectric conversion device characterized by the following features.

23. A substrate and A first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit are each arranged on the substrate and generate an electric charge based on incident light, The substrate is provided with a microlens that is commonly arranged in the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, A floating diffusion arranged on the aforementioned substrate, A first transfer transistor is disposed on the substrate and transfers the charge generated in the first photoelectric conversion unit to the floating diffusion, A second transfer transistor is disposed on the substrate and transfers the charge generated in the second photoelectric conversion unit to the floating diffusion, A third transfer transistor is disposed on the substrate and transfers the charge generated in the third photoelectric conversion unit to the floating diffusion, It has, In a plan view of the substrate, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged to be aligned in the first direction. The sensitivity of the third photoelectric conversion unit is lower than that of the first photoelectric conversion unit and the second photoelectric conversion unit. In the plan view, the third photoelectric conversion unit is arranged along a part of the outer periphery of a region including the first photoelectric conversion unit and the second photoelectric conversion unit. In the first direction, the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the second photoelectric conversion unit is greater than the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the first photoelectric conversion unit. A photoelectric conversion device characterized by the following features.

24. A substrate and A first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit are each arranged on the substrate and generate an electric charge based on incident light, The substrate is provided with a microlens that is commonly arranged in the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, A first separation unit is disposed on the substrate between the first photoelectric conversion unit and the second photoelectric conversion unit, A second separation unit is disposed on the substrate between the first photoelectric conversion unit and the third photoelectric conversion unit, A third separation unit is disposed on the substrate between the second photoelectric conversion unit and the third photoelectric conversion unit, It has, The saturation charge amount of the third photoelectric conversion unit is less than the saturation charge amount of the first photoelectric conversion unit and the saturation charge amount of the second photoelectric conversion unit. In a plan view of the substrate, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged to be aligned in the first direction. In a second direction perpendicular to the first direction, the center of gravity of the third photoelectric conversion unit is different from both the center of gravity of the first photoelectric conversion unit and the center of gravity of the second photoelectric conversion unit. The impurity concentration in the second separation section is higher than the impurity concentration in the first separation section. The impurity concentration in the third separation section is higher than the impurity concentration in the first separation section. A photoelectric conversion device characterized by the following features.

25. A substrate and A first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit are each arranged on the substrate and generate an electric charge based on incident light, The substrate is provided with a microlens that is commonly arranged in the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, A first separation unit is disposed on the substrate between the first photoelectric conversion unit and the second photoelectric conversion unit, A second separation unit is disposed on the substrate between the first photoelectric conversion unit and the third photoelectric conversion unit, A third separation unit is disposed on the substrate between the second photoelectric conversion unit and the third photoelectric conversion unit, It has, The saturation charge amount of the third photoelectric conversion unit is less than the saturation charge amount of the first photoelectric conversion unit and the saturation charge amount of the second photoelectric conversion unit. In a plan view of the substrate, the first photoelectric conversion unit and the second photoelectric conversion unit are arranged to be aligned in the first direction. In the first direction, the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the second photoelectric conversion unit is greater than the distance between the center of gravity of the third photoelectric conversion unit and the center of gravity of the first photoelectric conversion unit. The impurity concentration in the second separation section is higher than the impurity concentration in the first separation section. The impurity concentration in the third separation section is higher than the impurity concentration in the first separation section. A photoelectric conversion device characterized by the following features.

26. A photoelectric conversion device according to any one of claims 1 to 25, Optical device corresponding to the aforementioned photoelectric converter, A control device for controlling the aforementioned photoelectric converter, A processing device that processes the signal output from the aforementioned photoelectric converter, A display device that displays information obtained by the aforementioned photoelectric converter. A storage device for storing information obtained by the aforementioned photoelectric converter, and A device characterized by comprising at least one of the following: a mechanical device that operates based on information obtained from the photoelectric converter.

27. The processing device processes the image signals generated by each of the multiple photoelectric conversion units and acquires distance information from the photoelectric conversion device to the subject. The apparatus according to feature 26.

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