Photoelectric converter and photoelectric conversion system

Abstract

It provides technology that is advantageous for reducing DCR. [Solution] The photoelectric converter has a semiconductor layer having a first surface and a second surface. The semiconductor layer includes a first semiconductor region of a first conductivity type extending from the first surface toward the second surface, a second semiconductor region of the first conductivity type disposed between the first semiconductor region and the second surface so as to be in contact with the first semiconductor region, and a third semiconductor region of the second conductivity type disposed between the second semiconductor region and the second surface. The width of the second semiconductor region in the direction parallel to the first surface is greater than the width of the first semiconductor region in the direction parallel to the first surface, and less than the width of the third semiconductor region in the direction parallel to the first surface.

Description

[Technical Field]

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

[0002] Patent Document 1 describes a pixel applied to a SPAD (Single Photon Avalanche Diode). The pixel has a p-type semiconductor region, an n-type semiconductor region arranged from the surface of the substrate to the p-type semiconductor region, and a high-density n-type semiconductor region surrounded by the n-type semiconductor region. The pixel also has a hole accumulation region surrounding the p-type semiconductor region and the n-type semiconductor region, and a high-density p-type semiconductor region surrounding the n-type semiconductor region. In the configuration described in Patent Document 1, a strong electric field is formed near the surface of the substrate and around the n-type semiconductor region, which can generate a large DCR (Dark Count Rate). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2022 / 158233 [Overview of the project] [Problems that the invention aims to solve]

[0004] The present invention aims to provide a technology that is advantageous for reducing DCR. [Means for solving the problem]

[0005] One aspect of the present invention relates to a photoelectric converter having a semiconductor layer having a first surface and a second surface, wherein the semiconductor layer includes a first semiconductor region of a first conductivity type extending from the first surface toward the second surface, a second semiconductor region of a first conductivity type disposed between the first semiconductor region and the second surface so as to be in contact with the first semiconductor region, and a third semiconductor region of a second conductivity type disposed between the second semiconductor region and the second surface, wherein the width of the second semiconductor region in a direction parallel to the first surface is greater than the width of the first semiconductor region in a direction parallel to the first surface and less than the width of the third semiconductor region in a direction parallel to the first surface. [Effects of the Invention]

[0006] According to the present invention, a technology advantageous for reducing DCR is provided. [Brief explanation of the drawing]

[0007] [Figure 1] A diagram showing an example configuration of a photoelectric conversion device according to one embodiment. [Figure 2] A diagram showing an example configuration of the first circuit board. [Figure 3] A diagram showing an example configuration of the second circuit board. [Figure 4] A diagram showing an example configuration of a photoelectric conversion element and a pixel circuit. [Figure 5] A diagram illustrating the photon detection process. [Figure 6] A diagram showing an example configuration of the photoelectric conversion device according to the first embodiment. [Figure 7] A diagram showing an example configuration of the photoelectric conversion device according to the first embodiment. [Figure 8] A diagram showing an example configuration of a photoelectric conversion device according to the second embodiment. [Figure 9] A diagram showing an example configuration of a photoelectric conversion device according to the third embodiment. [Figure 10] A diagram showing an example configuration of the photoelectric conversion device according to the fourth embodiment. [Figure 11] A diagram showing an example configuration of the photoelectric conversion device according to the fourth embodiment. [Figure 12] A diagram showing an example configuration of the photoelectric conversion device according to the fifth embodiment. [Figure 13] Figure illustrating a configuration example of the photoelectric conversion device according to the sixth embodiment. [Figure 14] Figure illustrating a configuration example of the photoelectric conversion device according to the seventh embodiment. [Figure 15] Figure illustrating a configuration example of the photoelectric conversion device according to the seventh embodiment. [Figure 16] Figure illustrating a configuration example of the photoelectric conversion device according to the eighth embodiment. [Figure 17] Functional block diagram of the photoelectric conversion system according to the first application example. [Figure 18] Functional block diagram of the photoelectric conversion system according to the second application example. [Figure 19] Functional block diagram of the photoelectric conversion system according to the third application example. [Figure 20] Functional block diagram of the photoelectric conversion system according to the fourth application example. [Figure 21] Functional block diagram of the photoelectric conversion system according to the fifth application example. [Figure 22] Functional block diagram of the photoelectric conversion system according to the sixth application example. [Figure 23] Functional block diagram of the photoelectric conversion system according to the seventh application example. Description of Embodiments

[0008] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of the plurality of features are essential to the invention, and the plurality of features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant description is omitted.

[0009] In this specification, different conductivity types in a semiconductor region are distinguished as first conductivity type and second conductivity type. The first conductivity type is a conductivity type in which the majority carriers are of the first polarity, and the second conductivity type is a conductivity type in which the majority carriers are of the second polarity. When the first polarity is positive, the charge of the first polarity is a hole, and the first conductivity type is p-type. When the second polarity is negative, the charge of the second polarity is an electron, and the second conductivity type is n-type. Conversely, when the first polarity is negative, the charge of the first polarity is an electron, and the first conductivity type is n-type. When the second polarity is positive, the charge of the second polarity is a hole, and the second conductivity type is p-type.

[0010] Figure 1 schematically shows an example configuration of a photoelectric converter 100 according to one embodiment of the present disclosure. The photoelectric converter 100 may have a structure in which a first substrate 11 and a second substrate 21 are stacked. The first substrate 11 may include, for example, a photoelectric converter array 12 including a plurality of photoelectric converter elements (avalanche photodiodes, APDs). The second substrate 21 may include a processing circuit 22 that processes signals output from the plurality of photoelectric converter elements.

[0011] Figure 2 schematically shows an example configuration of the first substrate 11. The photoelectric conversion element array 12 of the first substrate 11 may include a plurality of photoelectric conversion elements 102 arranged to form a plurality of rows and a plurality of columns. Each photoelectric conversion element 102 constitutes a part of the pixel 101. In the following description, the photoelectric conversion device 100 is described exemplified as an imaging device. However, the photoelectric conversion device 100 may be configured as other devices. For example, the photoelectric conversion device 100 may be configured as a distance measuring device (e.g., a focus detection device, a distance measuring device using TOF (Time Of Flight)), or a photometer (e.g., a device for measuring the amount of incident light). The plurality of pixels 101 may be arranged in a line, in which case the photoelectric conversion device 100 may constitute a line sensor.

[0012] Figure 3 schematically shows the configuration of the processing circuit 22 of the second substrate 21. The processing circuit 22 may include, for example, a pixel circuit array 120 including a plurality of pixel circuits 103, a readout circuit 92, a control unit 95, a horizontal scanning circuit 91, a plurality of signal lines 93, a vertical scanning circuit 80, an output unit 94, etc. Each pixel circuit 103, together with its corresponding photoelectric conversion element 102, constitutes a pixel 101 and processes the signal output from the photoelectric conversion element 102. One pixel circuit 103 may be provided for one photoelectric conversion element 102, or one pixel circuit 103 may be provided for two or more photoelectric conversion elements 102. In one example, one photoelectric conversion element 102 and one pixel circuit 103 may be electrically connected by a connector. The pixel circuit 103 may include, for example, a counter and a memory. The memory may hold the count value counted by the counter. The photoelectric conversion element array 12 and the pixel circuit array 120 constitute a pixel array.

[0013] The vertical scanning circuit 80 may sequentially select multiple rows of the photoelectric conversion element array 12 according to a control signal supplied from the control unit 95. The vertical scanning circuit 80 may include, for example, at least one of a shift register and an address decoder. The readout circuit 92 reads signals output via multiple signal lines 93 from the pixel circuit 103 corresponding to the pixels 101 of the row selected by the vertical scanning circuit 80. The horizontal scanning circuit 91 supplies the signals of one row read out by the readout circuit 92 to the output unit 94 in a predetermined order.

[0014] Figure 4 shows an example configuration of a photoelectric conversion element 102 and a pixel circuit 103. In the example shown in Figure 4, one pixel circuit 103 is assigned to one photoelectric conversion element 102. The photoelectric conversion element 102 includes an APD201. At least one of the multiple components of the pixel circuit 103 may be placed on the first substrate 11. Alternatively, all of the multiple components of the pixel circuit 103 may be placed on the first substrate 11.

[0015] A first voltage VH can be applied to the cathode of the APD201. A second voltage VL is applied to the anode of the APD201, and the first voltage VH is at a higher potential than the second voltage VL. A potential difference between the first voltage VH and the second voltage VL is applied to the APD201 (between its anode and cathode). This potential difference is a reverse bias voltage that causes the APD201 to perform avalanche multiplication. The charge generated by photons incident on the APD201 causes avalanche multiplication, thereby generating an avalanche current. The mode in which a voltage greater than the breakdown voltage of the APD201 is applied between the anode and cathode of the APD201 is called Geiger mode. The mode in which a voltage near or below the breakdown voltage is applied between the anode and cathode of the APD201 is called linear mode. An APD operating in Geiger mode is called a SPAD. In one example, the first voltage VH is 1V and the second voltage VL is -30V.

[0016] The pixel circuit 103 may include a quench element 202 connected between a terminal to which a first voltage VH is supplied and the cathode of the APD201. The quench element 202 may be understood as an element that supplies the first voltage VH to the cathode of the APD201. The quench element 202 has the function of converting the change in avalanche current generated in the APD201 into a voltage signal. The quench element 202 functions as a load circuit (quench circuit) during signal multiplication by avalanche multiplication, suppressing avalanche multiplication by suppressing the voltage applied to the APD201. This function is known as quench operation.

[0017] The pixel circuit 103 may also include, for example, at least one of a waveform shaping unit 210, a counter circuit 211, and a selection circuit 212. The waveform shaping unit 210 can output a pulse signal by shaping the potential change of the cathode of the APD 201 when a photon is detected. The waveform shaping unit 210 may include, for example, an inverter circuit. In the example in Figure 4, the waveform shaping unit 210 is composed of one inverter, but the waveform shaping unit 210 may be composed of multiple inverters connected in series, or it may be composed of other circuits that have a waveform shaping effect.

[0018] The counter circuit 211 may be configured to count the pulse signal output from the waveform shaping unit 210 and to hold the resulting count value. When an active-level first control pulse is supplied from the vertical scanning circuit 80 via the drive line 213, the signal held in the counter circuit 211 may be reset. When an active-level second control pulse is supplied from the vertical scanning circuit 80 via the drive line 214, the selection circuit 212 may electrically connect the counter circuit 211 and the signal line 93. The selection circuit 212 may include, for example, a buffer circuit.

[0019] In this example, a counter circuit 211 is provided. However, the photoelectric converter 100 may be configured to acquire pulse detection timing by providing a Time to Digital Converter (TDC) instead of the counter circuit 211. In this case, the generation timing of the pulse signal output from the waveform shaping unit 210 can be converted into a digital signal by the TDC. A reference pulse (reference signal) may be supplied to the TDC via a drive line from the vertical scanning circuit 80 for measuring the timing of the pulse signal. The TDC can generate a digital signal corresponding to the generation timing of the pulse signal output from the waveform shaping unit 210, using the reference pulse as a reference.

[0020] Figure 5 illustrates the photon detection operation in the photoelectric converter 100. Figure 5(a) is an excerpt from Figure 4 showing the APD201, quench element 202, and waveform shaping unit 210. Here, the input side of the waveform shaping unit 210 is denoted as nodeA, and the output side as nodeB. Figure 5(b) shows the waveform of nodeA in Figure 5(a), and Figure 5(c) shows the waveform of nodeB in Figure 5(a). Between time t0 and t1, a potential difference of VH-VL is applied to the APD201. When a photon is incident at time t1, avalanche multiplication occurs in the APD201. As a result, an avalanche multiplication current flows through the quench element 202, and the voltage (potential) at nodeA drops. When the voltage drop increases and the potential difference applied to the APD201 becomes small, avalanche multiplication in the APD201 stops. Subsequently, a current flows through nodeA to compensate for the voltage drop from voltage VL, and at time t3, nodeA settles back to its original potential level. At this time, any portion of the output waveform at nodeA that exceeds a certain threshold is reshaped by the waveform shaping unit 210, and a pulse signal appears at nodeB.

[0021] The photoelectric converter 100 of the first embodiment will be described below with reference to Figures 6 and 7. Figure 6 is a schematic cross-sectional view showing the configuration of two pixels 101 among a plurality of pixels 101 of the photoelectric converter 100. Figure 7 is a schematic plan view showing three variations in the configuration of one pixel 101 among a plurality of pixels 101 of the photoelectric converter 100.

[0022] The photoelectric converter 100 has a semiconductor layer SL having a first surface S1 and a second surface S2. The semiconductor layer SL may be, for example, a semiconductor layer of a first substrate 11. The semiconductor layer SL may include a first semiconductor region 111 of a first conductivity type extending from the first surface S1 toward the second surface S2, and a second semiconductor region 113 of a first conductivity type disposed between the first semiconductor region 111 and the second surface S2 so as to be in contact with the first semiconductor region 111. The semiconductor layer SL may also include a third semiconductor region 114 of a second conductivity type disposed between the second semiconductor region 113 and the second surface S2. A strong electric field is generated between the second semiconductor region 113 and the third semiconductor region 114, forming an avalanche multiplication region.

[0023] Preferably, the width W2 of the second semiconductor region 113 in the direction parallel to the first surface S1 is greater than the width W1 of the first semiconductor region 111 in the same direction. Such a configuration is advantageous for suppressing the intensity of the electric field formed near the first surface S1 of the semiconductor layer SL and around the first semiconductor region 111, which can contribute to a reduction in the dark count rate (DCR). Preferably, the width W2 of the second semiconductor region 113 in the direction parallel to the first surface S1 is, for example, more than twice and less than or equal to four times the width W1 of the first semiconductor region 111 in the same direction.

[0024] The width W2 of the second semiconductor region 113 in the direction parallel to the first surface S1 is preferably smaller than the width W3 of the third semiconductor region 114. Such a configuration is advantageous for improving the charge collection effect to the avalanche multiplication region, which can contribute to suppressing signal charge count loss.

[0025] The semiconductor layer SL may further include a fourth semiconductor region 117, which includes a portion P1 positioned between the second semiconductor region 113 and the first surface so as to surround the first semiconductor region 111. Such a configuration is advantageous for suppressing the intensity of the electric field formed near the first surface S1 of the semiconductor layer SL and around the first semiconductor region 111, which can contribute to a reduction in DCR. The impurity concentration of the first conductivity type in the fourth semiconductor region 117 may be lower than the impurity concentration of the first conductivity type in the first semiconductor region 111 and the second semiconductor region 113. Here, the fourth semiconductor region 117 may be a semiconductor region of the first conductivity type, an intrinsic semiconductor region, or a semiconductor region of the second conductivity type.

[0026] In one example, the first semiconductor region 111 and the second semiconductor region 113 have an impurity concentration of 1 × 10⁻¹⁶ of the first conductivity type. 17 cm -3 The region includes the above-mentioned area, and the fourth semiconductor region 117 has an impurity concentration of 1 × 10⁻¹⁶ in the first conductivity type. 16 cm -3The region may include the following: The width W2 of the second semiconductor region 113 in a direction parallel to the first surface S1 is preferably at least twice the width W1 of the first semiconductor region 111 in that direction. The width W2 of the second semiconductor region 113 in a direction parallel to the first surface S1 is preferably four times or less the width of the first semiconductor region 111 in that direction. W2-W1 defines the width of a portion P1 disposed between the second semiconductor region 113 and the first surface so as to surround the first semiconductor region 111.

[0027] Each pixel 101 may include an active ACT comprising a first semiconductor region 111, a second semiconductor region 113, and a third semiconductor region 114. The semiconductor layer SL may include a pixel isolation region 131 disposed between adjacent pixels 101, and a fifth semiconductor region 116 of a second conductivity type disposed between the pixel isolation region 131 and a seventh semiconductor region 118, which will be described later. The fifth semiconductor region 116 of a second conductivity type may induce a charge having the polarity of majority carriers in the fifth semiconductor region 116. The semiconductor layer SL may include an eighth semiconductor region 112 of a second conductivity type disposed to connect the fifth semiconductor region 116 and the first surface S1. The impurity concentration of the second conductivity type in the eighth semiconductor region 112 may be higher than the impurity concentration of the second conductivity type in the fifth semiconductor region 116. A configuration in which the width W2 of the second semiconductor region 113 is greater than the width W1 of the first semiconductor region 111, that is, a configuration in which the width W1 of the first semiconductor region 111 is smaller than the width W2 of the second semiconductor region 113, is advantageous for reducing the electric field strength between the first semiconductor region 111 and the fifth semiconductor region 116.

[0028] The width W2 of the second semiconductor region 113 in a direction parallel to the first surface S1 is preferably smaller than the distance G between the second semiconductor region 113 and the pixel separation portion 131 in that direction. This configuration is also advantageous for suppressing the intensity of the electric field formed near the first surface S1 of the semiconductor layer SL and around the first semiconductor region 111, which can contribute to reducing the DCR. The dimension T2 of the second semiconductor region 113 in the thickness direction of the semiconductor layer SL (direction perpendicular to the first surface S1) is preferably, for example, 0.8 times or more and less than 2 times the dimension T1 of the first semiconductor region 111 in that thickness direction. W2-W1 defines the thickness of the portion P1 disposed between the second semiconductor region 113 and the first surface so as to surround the first semiconductor region 111.

[0029] The first semiconductor region 111 functions as the cathode of the APD201, and a first voltage VH can be applied through the first wiring pattern 123 and the first contact 121. The eighth semiconductor region 112 functions as the anode of the APD201, and a second voltage VL can be applied through the second wiring pattern 124 and the second contact 122.

[0030] The semiconductor layer SL may include a sixth semiconductor region 115 of a second conductivity type, positioned between the second surface S2 and the third semiconductor region 114. The sixth semiconductor region 115 may be positioned, for example, in contact with the second surface S2. The semiconductor layer SL may also include a seventh semiconductor region 118. In this embodiment, the seventh semiconductor region 118 may be a semiconductor region of a second conductivity type. The seventh semiconductor region 118 may include a portion positioned between the side surface of the fourth semiconductor region 117 and the fifth semiconductor region 116. The seventh semiconductor region 118 may include a portion positioned between the side surface of the third semiconductor region 114 and the fifth semiconductor region 116. The seventh semiconductor region 118 may include a portion positioned between the third semiconductor region 114 and the sixth semiconductor region 115.

[0031] In the example shown in Figure 7(a), the first semiconductor region 111 has a round shape such as a circle in plan view (orthogonal projection onto the first surface S1), the second semiconductor region 113 has a round shape such as a circle in plan view, and the fourth semiconductor region 117 has a round shape such as a circle in plan view. In the example shown in Figure 7(b), the first semiconductor region 111 has a round shape such as a circle in plan view, the second semiconductor region 113 has a rectangular shape in plan view, and the fourth semiconductor region 117 has a rectangular shape in plan view. In the example shown in Figure 7(c), the first semiconductor region 111 has a round shape such as a circle in plan view, the second semiconductor region 113 has a round shape such as a circle in plan view, and the fourth semiconductor region 117 has a rectangular shape in plan view.

[0032] The photoelectric converter 100 of the second embodiment will be described with reference to Figures 7 and 8. Figure 8 is a schematic cross-sectional view showing the configuration of two pixels 101 of a plurality of pixels 101 in the photoelectric converter 100 of the second embodiment. Figure 7 is a plan view used in the second embodiment, schematically showing three variations of the configuration of one pixel 101 of a plurality of pixels 101 in the photoelectric converter 100. Matters not mentioned in the description of the second embodiment may follow the first embodiment.

[0033] In the second embodiment, the first semiconductor region 111 and the second semiconductor region 113 include a portion in which the width in the direction parallel to the first surface S1 narrows from the second surface S2 toward the first surface S1. In other words, in the second embodiment, the first semiconductor region 111 and the second semiconductor region 113 have a shape in which the width in the direction parallel to the first surface S1 narrows from the second surface S2 toward the first surface S1. In the second embodiment, it is preferable that the maximum width W2 of the second semiconductor region 113 in the direction parallel to the first surface S1 is greater than the maximum width W1 of the first semiconductor region 111 in the same direction. Also in the second embodiment, it is preferable that the maximum width W2 of the second semiconductor region 113 in the same direction is smaller than the width W3 (or maximum width) of the third semiconductor region 114 in the same direction. It is preferable that the maximum width W2 of the second semiconductor region 113 in the direction parallel to the first surface S1 is smaller than the minimum distance G between the second semiconductor region 113 and the pixel separation portion 131 in the same direction.

[0034] In the first embodiment as well, W1, W2, and W3 may be specified as the maximum widths of the first semiconductor region 111, the second semiconductor region 113, and the third semiconductor region 114, respectively, in a direction parallel to the first surface S1. Also in the first embodiment as well, G may be specified as the minimum distance between the second semiconductor region 113 and the pixel separation portion 131 in a direction parallel to the first surface S1.

[0035] The photoelectric converter 100 of the third embodiment will be described with reference to Figures 7 and 9. Figure 9 is a schematic cross-sectional view showing the configuration of two pixels 101 of a plurality of pixels 101 of the photoelectric converter 100 of the third embodiment. Figure 7 is a plan view used in the third embodiment, schematically showing three variations of the configuration of one pixel 101 of a plurality of pixels 101 of the photoelectric converter 100. Matters not mentioned in the description of the third embodiment may follow the second embodiment. In the third embodiment, the first semiconductor region 111 and the second semiconductor region 113 include portions whose width in the direction parallel to the first surface S1 narrows toward the first surface S1. In other words, in the third embodiment, the first semiconductor region 111 and the second semiconductor region 113 have a shape in which the width in the direction parallel to the first surface S1 narrows toward the first surface S1.

[0036] The photoelectric converter 100 of the fourth embodiment will be described with reference to Figures 10 and 11. Figure 10 is a schematic cross-sectional view showing the configuration of two pixels 101 of a plurality of pixels 101 in the photoelectric converter 100 of the fourth embodiment. Figure 11 is a schematic plan view showing the configuration of one pixel 101 of a plurality of pixels 101 in the photoelectric converter 100 of the fourth embodiment. Matters not mentioned in the description of the fourth embodiment may follow the first to third embodiments. In the fourth embodiment, the second semiconductor region 113 has a ring shape. The region surrounded by the second semiconductor region 113 may have the same conductivity type and impurity concentration as the fourth semiconductor region 117, or it may have a different conductivity type and / or impurity concentration than the fourth semiconductor region 117.

[0037] The photoelectric converter 100 of the fifth embodiment will be described with reference to Figure 12. Figure 12 is a schematic cross-sectional view showing the configuration of two pixels 101 among a plurality of pixels 101 of the photoelectric converter 100 of the fifth embodiment. Matters not mentioned in the description of the fifth embodiment may follow the first to fourth embodiments. In the fifth embodiment, the third semiconductor region 114 extends to contact the fifth semiconductor region 116. Such a configuration may contribute to improving the charge collection efficiency.

[0038] In the fifth embodiment, the seventh semiconductor region 118 may be, for example, a first conductivity type semiconductor region, a second conductivity type semiconductor region, or an intrinsic semiconductor region. The seventh semiconductor region 118 may include a portion located between the side surface of the fourth semiconductor region 117 and the fifth semiconductor region 116. The seventh semiconductor region 118 may include a portion located between the side surface of the third semiconductor region 114 and the fifth semiconductor region 116. The seventh semiconductor region 118 may include a portion located between the third semiconductor region 114 and the sixth semiconductor region 115.

[0039] The photoelectric converter 100 of the sixth embodiment will be described with reference to Figure 13. Figure 13 is a schematic cross-sectional view showing the configuration of two pixels 101 of a plurality of pixels 101 of the photoelectric converter 100 of the sixth embodiment. Matters not mentioned in the description of the sixth embodiment may be in accordance with the first to fifth embodiments. For example, in the sixth embodiment, as shown in Figure 12, the third semiconductor region 114 may extend to contact the fifth semiconductor region 116. In the sixth embodiment, the fourth semiconductor region 117 includes a portion P2 located between the second semiconductor region 113 and the third semiconductor region 114. In other words, the entire periphery of the second semiconductor region 113 may be surrounded by the first semiconductor region 111 and the fourth semiconductor region 117. The fourth semiconductor region 117 is advantageous for mitigating the electric field around the second semiconductor region 113. The fourth semiconductor region 117 may have, for example, an impurity concentration of 1 × 10⁻⁶ of the first conductivity type. 16 cm -3 The following areas are included.

[0040] The photoelectric converter 100 of the seventh embodiment will be described with reference to Figures 6, 14, and 15. Figure 14 is a schematic cross-sectional view showing the configuration of each of two pixels 101 of the plurality of pixels 101 of the photoelectric converter 100 of the seventh embodiment, cut along the line B-B' in Figure 15(a). Figure 6 is a schematic cross-sectional view used in the seventh embodiment, showing the configuration of each of two pixels 101 of the plurality of pixels 101 of the photoelectric converter 100 of the seventh embodiment, cut along the line A-A' in Figure 15(a). Figure 15 is a schematic plan view showing three variations of the configuration of one pixel 101 of the plurality of pixels 101 of the photoelectric converter 100. Matters not mentioned in the description of the seventh embodiment may follow the first to sixth embodiments. For example, in the seventh embodiment, as shown in Figure 12, the third semiconductor region 114 may extend to contact the fifth semiconductor region 116.

[0041] In the seventh embodiment, the fifth semiconductor region 116 may be arranged so as not to surround the first semiconductor region 111. Alternatively, in the seventh embodiment, the fifth semiconductor region 116 may be arranged so as not to surround the first semiconductor region 111 and the second semiconductor region 113.

[0042] From another perspective, the eighth semiconductor region 112 may be located within the active region ACT, and in the region furthest from the first semiconductor region 111 among the regions lateral to the first semiconductor region 111. Alternatively, the eighth semiconductor region 112 may be located within the active region ACT, and in the region furthest from the first semiconductor region 111 among the regions lateral to the first semiconductor region 111 and the second semiconductor region 113.

[0043] From another perspective, the eighth semiconductor region 112 may be located at the corner of the active region ACT. Alternatively, the multiple pixels 101 may be arranged to form a rectangular grid, and the eighth semiconductor region 112 may be located diagonally across the rectangular grid as viewed from the first semiconductor region 111.

[0044] Between the fifth semiconductor region 116 and the first surface S1, the eighth semiconductor region 112 is located, which functions as the anode of APD201, and a second voltage VL can be applied through the second wiring pattern 124 and the second contact 122. Along the line B-B' in Figure 15(a), a portion of the seventh semiconductor region 118 is located between the fifth semiconductor region 116 and the first surface S1.

[0045] The photoelectric converter 100 of the eighth embodiment will be described with reference to Figures 7 and 16. Figure 16 is a schematic cross-sectional view showing the configuration of two pixels 101 of a plurality of pixels 101 in the photoelectric converter 100 of the eighth embodiment. Figure 7 is a plan view used in the eighth embodiment, schematically showing three variations of the configuration of one pixel 101 of a plurality of pixels 101 in the photoelectric converter 100. Matters not mentioned in the description of the eighth embodiment may follow the first to seventh embodiments. For example, in the eighth embodiment, as shown in Figure 12, the third semiconductor region 114 may extend to contact the fifth semiconductor region 116.

[0046] The eighth embodiment focuses on the relationship between the dimension T1 of the first semiconductor region 111 and the dimension T2 of the second semiconductor region 113 in the thickness direction of the semiconductor layer SL (the direction perpendicular to the first surface S1). Dimension T2 is preferably 0.8 times or more and less than 2 times the dimension T1, and more preferably 1 time or more and less than 2 times the dimension T1.

[0047] The photoelectric conversion system relating to the first application example will be described below with reference to Figure 17. Figure 17 is a block diagram showing the schematic configuration of the photoelectric conversion system relating to the first application example.

[0048] The photoelectric conversion device 100 described above is applicable to various photoelectric conversion systems. Examples of applicable photoelectric conversion systems include digital still cameras, digital camcorders, surveillance cameras, photocopiers, fax machines, mobile phones, in-vehicle cameras, and observation satellites. Camera modules, which include optical systems such as lenses and imaging devices, are also included in photoelectric conversion systems. Figure 17 shows a block diagram of a digital still camera as an example of these.

[0049] The photoelectric conversion system 1000 illustrated in Figure 17 includes an imaging device 1004, which is an example of a photoelectric conversion device. The photoelectric conversion system 1000 also includes a lens 1002 for forming an optical image of a subject onto the imaging device 1004, an aperture 1003 for varying the amount of light passing through the lens 1002, and a barrier 1001 for protecting the lens 1002. The lens 1002 and aperture 1003 are an optical system (optical device) that focuses light onto the imaging device 1004. The imaging device 1004 is a photoelectric conversion device 100 (imaging device) of any of the above embodiments, which converts the optical image formed by the lens 1002 into an electrical signal.

[0050] The photoelectric conversion system 1000 also includes a signal processing unit 1007, which is an image generation unit that generates an image by processing the output signal output by the imaging device 1004. The signal processing unit 1007 functions as a processing device that performs various corrections and compressions as needed and outputs image data. The signal processing unit 1007 may be formed on the semiconductor substrate on which the imaging device 1004 is provided, or it may be formed on a semiconductor substrate separate from the imaging device 1004. Alternatively, the imaging device 1004 and the signal processing unit 1007 may be formed on the same semiconductor substrate.

[0051] The photoelectric conversion system 1000 further includes a memory unit 1010 for temporarily storing image data, and an external interface unit (external I / F unit) 1013 for communicating with an external computer or the like. Furthermore, the photoelectric conversion system 1000 includes a recording medium 1012 such as a semiconductor memory for recording or reading imaging data, and a recording medium control interface unit (recording medium control I / F unit) 1011 for recording or reading data from the recording medium 1012. The recording medium control I / F unit 1011 and the recording medium 1012 can constitute part of a storage device. The recording medium 1012 may be built into the photoelectric conversion system 1000 or it may be detachable.

[0052] Furthermore, the photoelectric conversion system 1000 includes an overall control / calculation unit 1009 that controls various calculations and the entire digital still camera, and a timing generation unit 1008 that outputs various timing signals to the imaging device 1004 and the signal processing unit 1007. The overall control / calculation unit 1009 and the timing generation unit 1008 can constitute part of a control device for controlling the operation of the photoelectric conversion system 1000. Here, timing signals and the like may be input from an external source, and the photoelectric conversion system 1000 only needs to include at least an imaging device 1004 and a signal processing unit 1007 that processes output signals output from the imaging device 1004.

[0053] The imaging device 1004 outputs an imaging signal to the signal processing unit 1007. The signal processing unit 1007 performs predetermined signal processing on the imaging signal output from the imaging device 1004 and outputs image data. The signal processing unit 1007 generates an image using the imaging signal. Although not shown in Figure 17, a display device such as a display for displaying the generated image may be provided in the photoelectric conversion system 1000. Thus, according to this application example, a photoelectric conversion system 1000 can be realized by applying a photoelectric conversion device 100 (imaging device) of any of the above embodiments.

[0054] The photoelectric conversion system 1300 and mobile unit 1301 according to the second application example will be explained using Figures 18(a) and 18(b). Figures 18(a) and 18(b) are diagrams showing the configuration of the photoelectric conversion system 1300 and mobile unit 1301 according to the second application example.

[0055] Figure 18(a) shows an example of a photoelectric conversion system related to an in-vehicle camera. The photoelectric conversion system 1300 has an imaging device 1310. The imaging device 1310 is the photoelectric conversion system 100 (imaging device) described in any of the embodiments above. The photoelectric conversion system 1300 has an image processing unit 1312 that performs image processing on a plurality of image data acquired by the imaging device 1310. The photoelectric conversion system 1300 also has a distance acquisition unit 1316 that calculates the distance to an object, and a collision determination unit 1318 that determines whether or not there is a possibility of collision based on the calculated distance. Here, the distance acquisition unit 1316 may acquire distance information to the object using the Time of Flight (ToF) method, or it may acquire distance information using parallax information, etc. That is, distance information is information related to parallax, defocus amount, distance to the object, etc. The collision determination unit 1318 may determine the possibility of collision using any of this distance information. The distance acquisition unit 1316 may be implemented by specially designed hardware or by a software module. Alternatively, the distance acquisition unit 1316 may be implemented by an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). Furthermore, the distance acquisition unit 1316 may be implemented by a combination of these.

[0056] The photoelectric conversion system 1300 is connected to the vehicle information acquisition device 1320 and can acquire vehicle information such as vehicle speed, yaw rate, and steering angle. The photoelectric conversion system 1300 is also connected to the ECU 1330, which is a control device that outputs a control signal to generate braking force on the vehicle based on the judgment result of the collision judgment unit 1318. The photoelectric conversion system 1300 is also connected to the warning device 1340, which issues a warning to the driver based on the judgment result of the collision judgment unit 1318. For example, if the collision judgment result of the collision judgment unit 1318 indicates a high probability of collision, the ECU 1330 controls the drive unit (mechanical device) 1360 by applying the brakes, releasing the accelerator, or suppressing engine output to perform vehicle control to avoid a collision or mitigate damage. The warning device 1340 warns the user by sounding an alarm, displaying warning information on a screen such as a car navigation system, or vibrating the seat belt or steering wheel.

[0057] In this application example, the photoelectric conversion system 1300 images the area around the vehicle (mobile body 1301), for example, in front of or behind it. Figure 18(b) shows the photoelectric conversion system when imaging the area in front of the vehicle (imaging range 1350). The vehicle information acquisition device 1320 sends instructions to the photoelectric conversion system 1300 or the imaging device 1310. This configuration can further improve the accuracy of distance measurement.

[0058] The above example describes control to prevent collisions with other vehicles, but the photoelectric conversion system 1300 can also be applied to control systems that automatically follow other vehicles or automatically drive to prevent vehicles from straying from their lanes. Furthermore, the photoelectric conversion system 1300 can be applied not only to vehicles such as automobiles, but also to mobile bodies (mobile devices) such as ships, aircraft, or industrial robots. This mobile body mainly includes a drive force generation unit that generates the driving force used for the movement of the mobile body, and one or both of a rotating body mainly used for the movement of the mobile body. The drive force generation unit may be an engine, motor, etc. The rotating body may be a tire, wheel, ship's propeller, mobile body's propeller, etc. In addition, it can be applied not only to mobile bodies, but also to a wide range of devices that utilize object recognition, such as intelligent transportation systems (ITS).

[0059] A photoelectric conversion system relating to the third application example will be described using Figure 19. Figure 19 is a block diagram showing an example configuration of the distance image sensor 1401, which is a photoelectric conversion system of this embodiment.

[0060] As shown in Figure 19, the distance image sensor 1401 comprises an optical system 1407, a photoelectric converter 1408, an image processing circuit 1404, a monitor 1405, and a memory 1406. The distance image sensor 1401 receives light (modulated light or pulsed light) that is projected from a light source device 1409 toward the subject and reflected from the surface of the subject, thereby acquiring a distance image corresponding to the distance to the subject.

[0061] The optical system 1407 is composed of one or more lenses and guides the image light (incident light) from the subject to the photoelectric converter 1408, where it forms an image on the light-receiving surface (sensor part) of the photoelectric converter 1408.

[0062] As the photoelectric converter 1408, the photoelectric converter 100 of each embodiment described above is applied, and a distance signal indicating the distance determined from the received light signal output from the photoelectric converter 1408 is supplied to the image processing circuit 1404.

[0063] The image processing circuit 1404 performs image processing to construct a distance image based on the distance signal supplied from the photoelectric converter 1408. The distance image (image data) obtained through this image processing is then supplied to the monitor 1405 for display or supplied to the memory 1406 for storage (recording).

[0064] With the distance image sensor 1401 configured in this way, by applying the photoelectric converter 100 described above, the characteristics of the pixels are improved, and for example, more accurate distance images can be acquired.

[0065] The photoelectric conversion system relating to the fourth application example will be explained using Figure 20. Figure 20 is a diagram showing an example of the schematic configuration of the endoscopic surgical system 1250, which is a photoelectric conversion system relating to the fourth application example.

[0066] Figure 20 illustrates a surgeon (physician) 1231 performing surgery on a patient 1232 on a patient bed 1233 using an endoscopic surgical system 1250. As shown in the figure, the endoscopic surgical system 1250 consists of an endoscope 1200, surgical instruments 1210, and a cart 1234 equipped with various devices for endoscopic surgery.

[0067] The endoscope 1200 comprises a barrel 1201, the portion of which a predetermined length from the tip is inserted into the body cavity of the patient 1232, and a camera head 1202 connected to the proximal end of the barrel 1201. In the illustrated example, the endoscope 1200 is shown as a so-called rigid endoscope having a rigid barrel 1201, but the endoscope 1200 may also be configured as a so-called flexible endoscope having a flexible barrel.

[0068] An opening into which an objective lens is fitted is provided at the tip of the endoscope tube 1201. A light source device 1203 is connected to the endoscope 1200, and the light generated by the light source device 1203 is guided to the tip of the endoscope tube by a light guide extending inside the endoscope tube 1201, and is irradiated through the objective lens towards the object to be observed inside the body cavity of the patient 1232. The endoscope 1200 may be a straight-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0069] The camera head 1202 contains an optical system and a photoelectric converter. Reflected light from the object being observed (observation light) is focused by the optical system into the photoelectric converter. The photoelectric converter converts the observation light into electrical signals, generating an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The photoelectric converter can be any of the photoelectric converters 100 (imaging devices) described in the embodiments described above. The image signal is transmitted as RAW data to the camera control unit (CCU) 1235.

[0070] The CCU1235 consists of a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit), and comprehensively controls the operation of the endoscope 1200 and the display device 1236. Furthermore, the CCU1235 receives an image signal from the camera head 1202 and performs various image processing operations on that image signal, such as development processing (demosaic processing), to display an image based on that image signal.

[0071] The display device 1236 displays an image based on an image signal that has been processed by the CCU 1235, under control from the CCU 1235.

[0072] The light source device 1203 consists of a light source such as an LED (Light Emitting Diode) and supplies illumination light to the endoscope 1200 when photographing the surgical area.

[0073] The input device 1237 is an input interface for the endoscopic surgical system 1250. The user can input various types of information and instructions to the endoscopic surgical system 1250 via the input device 1237.

[0074] The treatment instrument control device 1238 controls the driving of the energy treatment instrument 1212 for purposes such as tissue cauterization, incision, or blood vessel sealing.

[0075] The light source device 1203, which supplies illumination light to the endoscope 1200 when photographing the surgical area, can be composed of, for example, an LED, a laser light source, or a combination thereof. When the white light source is composed of a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, so the white balance of the captured image can be adjusted in the light source device 1203. In this case, it is also possible to capture images corresponding to each of the RGB colors in time-division by irradiating the observation target with laser light from each of the RGB laser light sources in time-division and controlling the drive of the image sensor of the camera head 1202 in synchronization with the irradiation timing. According to this method, a color image can be obtained without providing a color filter on the image sensor.

[0076] Furthermore, the light source device 1203 may be controlled to change the intensity of the light it outputs at predetermined time intervals. By controlling the drive of the image sensor of the camera head 1202 in synchronization with the timing of the change in light intensity, images can be acquired in time-division order, and these images can be combined to generate high dynamic range images without so-called black crushing and white clipping.

[0077] Furthermore, the light source device 1203 may be configured to supply light in a predetermined wavelength band corresponding to special light observation. In special light observation, for example, the wavelength dependence of light absorption in body tissue is utilized. Specifically, by irradiating with narrowband light compared to the irradiation light used during normal observation (i.e., white light), predetermined tissues such as blood vessels on the surface of mucosa can be imaged with high contrast. Alternatively, in special light observation, fluorescence observation may be performed to obtain an image using fluorescence generated by irradiation with excitation light. In fluorescence observation, excitation light can be irradiated onto body tissue and fluorescence from the body tissue can be observed, or a reagent such as indocyanine green (ICG) can be injected into body tissue and the body tissue can be irradiated with excitation light corresponding to the fluorescence wavelength of the reagent to obtain a fluorescence image. The light source device 1203 may be configured to supply narrowband light and / or excitation light corresponding to such special light observation.

[0078] The photoelectric conversion system according to the fifth application example will be explained using Figures 21(a) and 21(b). Figure 21(a) illustrates the eyeglasses 1600 (smart glasses), which are a photoelectric conversion system according to the fifth application example. The eyeglasses 1600 have a photoelectric conversion device 1602. The photoelectric conversion device 1602 is the photoelectric conversion device 100 (imaging device) described in each of the embodiments above. In addition, a display device including a light-emitting device such as an OLED or LED may be provided on the back side of the lens 1601. There may be one or more photoelectric conversion devices 1602. In addition, multiple types of photoelectric conversion devices may be used in combination. The arrangement position of the photoelectric conversion device 1602 is not limited to that shown in Figure 21(a).

[0079] The eyeglasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the photoelectric converter 1602 and the display device. The control device 1603 also controls the operation of the photoelectric converter 1602 and the display device. The lens 1601 has an optical system formed therein for focusing light onto the photoelectric converter 1602.

[0080] Figure 21(b) illustrates a pair of glasses 1610 (smart glasses) according to one application example. The glasses 1610 have a control device 1612, which is equipped with a photoelectric converter equivalent to a photoelectric converter 1602 and a display device. The lens 1611 has an optical system formed therein for projecting light emitted from the photoelectric converter in the control device 1612 and from the display device, and an image is projected onto the lens 1611. The control device 1612 functions as a power supply that provides power to the photoelectric converter and the display device, and also controls the operation of the photoelectric converter and the display device. The control device may have a gaze detection unit that detects the wearer's gaze. Gaze detection may use infrared light. The infrared light emitter emits infrared light towards the eyeball of the user who is fixating on the displayed image. An imaging unit having a light-receiving element detects the reflected light from the eyeball of the emitted infrared light, thereby obtaining an image of the eyeball. By having a reduction means that reduces the light from the infrared light emitter to the display unit in planar view, the deterioration of image quality is reduced.

[0081] The user's gaze towards a displayed image is detected from an image of the eyeball obtained by imaging with infrared light. Any known method can be applied to gaze detection using an image of the eyeball. As an example, a gaze detection method based on the Purkinje image obtained by the reflection of the irradiated light from the cornea can be used.

[0082] More specifically, gaze detection processing is performed based on the pupil-corneal reflection method. Using the pupil-corneal reflection method, a gaze vector representing the orientation (rotation angle) of the eyeball is calculated based on the pupil image and Purkinje image contained in the captured image of the eyeball, thereby detecting the user's gaze.

[0083] The display device in this application example has a photoelectric converter with a light-receiving element, and may control the display image of the display device based on the user's gaze information from the photoelectric converter.

[0084] Specifically, the display device determines a first field of view that the user is fixated on, and a second field of view other than the first field of view, based on gaze information. The first and second field of view may be determined by the control device of the display device, or they may be determined by an external control device and received by the display device. Within the display area of ​​the display device, the display resolution of the first field of view may be controlled to be higher than the display resolution of the second field of view. In other words, the resolution of the second field of view may be lower than that of the first field of view.

[0085] Furthermore, the display area has a first display area and a second display area different from the first display area, and a higher priority area may be determined from the first and second display areas based on gaze information. The first and second view areas may be determined by the control device of the display device, or they may be determined by an external control device and received. The resolution of the higher priority area may be controlled to be higher than the resolution of the areas other than the higher priority area. In other words, the resolution of areas with relatively lower priority may be set lower.

[0086] AI may be used to determine the first field of view area and high-priority areas. The AI ​​may be a model configured to estimate the angle of gaze and the distance to the target object at the end of the line of sight from the image of the eye, using the image of the eye and the direction the eye was actually looking in that image as training data. The AI ​​program may be installed in the display device, the photoelectric converter, or an external device. If installed in an external device, it will be transmitted to the display device via communication.

[0087] When display control is based on visual detection, this method is preferably applicable to smart glasses that further include a photoelectric converter for capturing images of the surrounding environment. The smart glasses can display the captured external information in real time.

[0088] The sixth application example will be explained using Figures 22(a) and 22(b). The photoelectric conversion device and photoelectric conversion system described above may be applied to electronic devices such as smartphones and tablets.

[0089] Figures 22(a) and 22(b) show an example of an electronic device 1500 equipped with a photoelectric converter. Figure 22(a) shows the front side of the electronic device 1500, and Figure 22(b) shows the back side of the electronic device 1500.

[0090] As shown in Figure 22(a), a display 1510 for displaying images is positioned in the center of the surface of the electronic device 1500. Along the upper edge of the surface of the electronic device 1500, the front cameras 1521 and 1522, which use the photoelectric converter 100, an IR light source 1530 that emits infrared light, and a visible light source 1540 that emits visible light are positioned.

[0091] Furthermore, as shown in Figure 22(b), rear cameras 1551 and 1552, which use the photoelectric converter 100, an IR light source 1560 that emits infrared light, and a visible light source 1570 that emits visible light are arranged along the upper edge of the back of the electronic device 1500.

[0092] In the electronic device 1500 configured in this way, applying the photoelectric converter 100 described above makes it possible to capture, for example, higher-quality images. The photoelectric converter can also be applied to other electronic devices such as infrared sensors, distance measuring sensors using active infrared light sources, security cameras, and personal or biometric authentication cameras. This improves the accuracy and performance of these electronic devices.

[0093] Figure 23 is a block diagram of an X-ray CT apparatus according to the seventh application example. The photoelectric converter 100 described above is applicable to the detector of the X-ray CT apparatus. The X-ray CT apparatus 30 according to this application example comprises an X-ray generator 310, a wedge 316, a collimator 318, an X-ray detection unit 320, a top plate 330, a rotating frame 340, and a high-voltage generator 350. The X-ray CT apparatus 30 also comprises a data acquisition system (DAS) 351, a signal processing unit 352, a display unit 353, and a control unit 354.

[0094] The X-ray generator 310 is composed of, for example, a vacuum tube that generates X-rays. The vacuum tube of the X-ray generator 310 is supplied with high voltage and filament current from the high voltage generator 350. X-rays are generated when thermionic electrons are irradiated from the cathode (filament) to the anode (target).

[0095] The wedge 316 is a filter that adjusts the amount of X-rays irradiated from the X-ray generator 310. The wedge 316 attenuates the amount of X-rays so that the X-rays irradiated from the X-ray generator 310 to the subject have a predetermined distribution. The collimator 318 is made up of a lead plate or the like that narrows the irradiation range of the X-rays that have passed through the wedge 316. The X-rays generated in the X-ray generator 310 are formed into a cone beam shape via the collimator 318 and irradiated onto the subject on the top plate 330.

[0096] The X-ray detection unit 320 is configured using the photoelectric converter 100 described above. The X-ray detection unit 320 detects the X-rays that have passed through the subject from the X-ray generation unit 310 and outputs a signal corresponding to the X-ray dose to the DAS351.

[0097] The rotating frame 340 is annular in shape and is configured to rotate. Inside the rotating frame 340, the X-ray generating unit 310 (wedge 316, collimator 318) and the X-ray detection unit 320 are arranged facing each other. The X-ray generating unit 310 and the X-ray detection unit 320 are rotatable together with the rotating frame 340.

[0098] The high-voltage generator 350 includes a boost circuit and outputs a high voltage to the X-ray generator 310. The DAS 351 includes an amplification circuit and an A / D conversion circuit and outputs the signal from the X-ray detection unit 320 as digital data to the signal processing unit 352.

[0099] The signal processing unit 352 includes a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory), and is capable of performing image processing on digital data. The display unit 353 includes a flat-panel display device, and is capable of displaying X-ray images. The control unit 354 includes a CPU, ROM, RAM, etc., and controls the operation of the entire X-ray CT apparatus 30.

[0100] The disclosures in this specification include the following components: (Item 1) A photoelectric conversion device having a semiconductor layer having a first surface and a second surface, The semiconductor layer includes a first semiconductor region of a first conductivity type extending from the first surface toward the second surface, a second semiconductor region of the first conductivity type disposed between the first semiconductor region and the second surface so as to be in contact with the first semiconductor region, and a third semiconductor region of the second conductivity type disposed between the second semiconductor region and the second surface. The width of the second semiconductor region in the direction parallel to the first plane is greater than the width of the first semiconductor region in the direction parallel to the first plane, and less than the width of the third semiconductor region in the direction parallel to the first plane. A photoelectric conversion device characterized by the following features. (Item 2) The width of the second semiconductor region in a direction parallel to the first surface is at least twice and no more than four times the width of the first semiconductor region in a direction parallel to the first surface. A photoelectric conversion device as described in item 1, characterized by the features described herein. (Item 3) The semiconductor layer further includes a fourth semiconductor region which includes a portion disposed between the second semiconductor region and the first surface so as to surround the first semiconductor region. The impurity concentration of the first conductivity type in the fourth semiconductor region is lower than the impurity concentration of the first conductivity type in the first and second semiconductor regions. A photoelectric conversion device according to item 1 or 2, characterized by the above. (Item 4) The fourth semiconductor region is the semiconductor region of the first conductivity type, an intrinsic semiconductor region, or the semiconductor region of the second conductivity type, The photoelectric conversion device according to item 3, characterized in that: (Item 5) The first semiconductor region and the second semiconductor region have an impurity concentration of the first conductivity type of 1×10 17 cm -3 or higher, and comprise a region satisfying the above condition, The fourth semiconductor region has an impurity concentration of the first conductivity type of 1×10 16 cm -3 or lower, and comprise a region satisfying the above condition, The photoelectric conversion device according to item 3 or 4, characterized in that: (Item 6) The width of the second semiconductor region in a direction parallel to the first surface is at least twice the width of the first semiconductor region in the direction parallel to the first surface, The photoelectric conversion device according to any one of items 1 to 5, characterized in that: (Item 7) The width of the second semiconductor region in a direction parallel to the first surface is at most four times the width of the first semiconductor region in the direction parallel to the first surface, The photoelectric conversion device according to item 6, characterized in that: (Item 8) Comprising a plurality of pixels, Each pixel has an active region including the first semiconductor region, the second semiconductor region and the third semiconductor region, The active region includes a seventh semiconductor region disposed between the third semiconductor region and the second surface, The semiconductor layer includes a pixel isolation portion disposed between adjacent pixels, and a fifth semiconductor region of the second conductivity type disposed between the pixel isolation portion and the seventh semiconductor region, The photoelectric conversion device according to any one of items 1 to 7, characterized in that: (Item 9) The third semiconductor region extends so as to be in contact with the fifth semiconductor region, The photoelectric conversion device according to item 8, characterized in that: (Item 10) The semiconductor layer further includes a fourth semiconductor region disposed between the first surface and the third semiconductor region so as to surround the sides of the first and second semiconductor regions, wherein the impurity concentration of the first conductivity type in the fourth semiconductor region is lower than the impurity concentration of the first conductivity type in the first and second semiconductor regions. A photoelectric conversion device as described in item 8, characterized by the features described above. (Item 11) The fourth semiconductor region is the first conductivity type semiconductor region, the intrinsic semiconductor region, or the second conductivity type semiconductor region. A photoelectric conversion device as described in item 10, characterized by the features described herein. (Item 12) The first semiconductor region and the second semiconductor region have an impurity concentration of 1 × 10⁻¹⁶ of the first conductivity type. 17 cm -3 Including the region that is above, The fourth semiconductor region has an impurity concentration of 1 × 10⁻⁶ of the first conductivity type. 16 cm -3 The following areas include: A photoelectric conversion device as described in item 10, characterized by the features described herein. (Item 13) The fourth semiconductor region includes a portion located between the second semiconductor region and the third semiconductor region. A photoelectric conversion device according to any one of items 10 to 12, characterized in that it is a photoelectric conversion device. (Item 14) The fifth semiconductor region is arranged so as not to surround the first semiconductor region. A photoelectric conversion device according to any one of items 8 to 13, characterized by the features described herein. (Item 15) The fifth semiconductor region is arranged so as not to surround the first semiconductor region and the second semiconductor region. A photoelectric conversion device according to any one of items 8 to 13, characterized by the features described herein. (Item 16) The width of the second semiconductor region in the direction parallel to the first plane is smaller than the distance between the second semiconductor region and the pixel separation portion in the direction parallel to the first plane. A photoelectric conversion device according to any one of items 8 to 14, characterized by the features described herein. (Item 17) The dimensions of the second semiconductor region in the thickness direction of the semiconductor layer are 0.8 times or more and less than 2 times the dimensions of the first semiconductor region in the thickness direction of the semiconductor layer. A photoelectric conversion device according to any one of items 1 to 16, characterized in that it is a photoelectric conversion device. (Item 18) The first semiconductor region and the second semiconductor region include portions whose width in a direction parallel to the first surface narrows toward the first surface. A photoelectric conversion device according to any one of items 1 to 17, characterized by the features described herein. (Item 19) The second semiconductor region has a ring shape, A photoelectric conversion device according to any one of items 1 to 17, characterized by the features described herein. (Item 20) A photoelectric conversion device having a semiconductor layer having a first surface and a second surface, The semiconductor layer includes a first semiconductor region of a first conductivity type extending from the first surface toward the second surface, a second semiconductor region of a first conductivity type disposed between the first semiconductor region and the second surface so as to be in contact with the first semiconductor region, a third semiconductor region of a second conductivity type disposed between the second semiconductor region and the second surface, and a pixel separation portion surrounding the first semiconductor region, the second semiconductor region, and the third semiconductor region. The width of the second semiconductor region in the direction parallel to the first plane is smaller than the distance between the second semiconductor region and the pixel separation portion in the direction parallel to the first plane. A photoelectric conversion device characterized by the following features. (Item 21) The width of the second semiconductor region in a direction parallel to the first surface is at least twice and no more than four times the width of the first semiconductor region in a direction parallel to the first surface. A photoelectric conversion device as described in item 20, characterized by the features described herein. (Item 22) The semiconductor layer further includes a fourth semiconductor region which includes a portion disposed between the second semiconductor region and the first surface so as to surround the first semiconductor region. The impurity concentration of the first conductivity type in the fourth semiconductor region is lower than the impurity concentration of the first conductivity type in the first and second semiconductor regions. A photoelectric conversion device as described in item 20, characterized by the features described herein. (Item 23) The fourth semiconductor region is the first conductivity type semiconductor region, the intrinsic semiconductor region, or the second conductivity type semiconductor region. A photoelectric conversion device as described in item 22, characterized by the features described herein. (Item 24) The first semiconductor region and the second semiconductor region have an impurity concentration of 1 × 10⁻¹⁶ of the first conductivity type. 17 cm -3 Including the region that is above, The fourth semiconductor region has an impurity concentration of 1 × 10⁻⁶ of the first conductivity type. 16 cm -3 The following areas include: A photoelectric conversion device as described in item 22, characterized by the features described herein. (Item 25) The width of the second semiconductor region in a direction parallel to the first surface is at least twice the width of the first semiconductor region in a direction parallel to the first surface. A photoelectric conversion device according to any one of items 22 to 24, characterized in that it is a photoelectric conversion device. (Item 26) The width of the second semiconductor region in a direction parallel to the first surface is no more than four times the width of the first semiconductor region in a direction parallel to the first surface. A photoelectric conversion device as described in item 25, characterized by the features described herein. (Item 27) Having multiple pixels, Each pixel has an active region including the first semiconductor region, the second semiconductor region, and the third semiconductor region. The active region includes a seventh semiconductor region disposed between the third semiconductor region and the second surface. The semiconductor layer includes a fifth semiconductor region of the second conductivity type disposed between the pixel separation portion and the seventh semiconductor region. A photoelectric conversion device according to any one of items 20 to 26, characterized by the features described herein. (Item 28) The third semiconductor region extends so as to be in contact with the fifth semiconductor region. A photoelectric conversion device as described in item 27, characterized by the features described herein. (Item 29) The semiconductor layer further includes a fourth semiconductor region disposed between the first surface and the third semiconductor region so as to surround the sides of the first and second semiconductor regions, wherein the impurity concentration of the first conductivity type in the fourth semiconductor region is lower than the impurity concentration of the first conductivity type in the first and second semiconductor regions. A photoelectric conversion device as described in item 27, characterized by the features described herein. (Item 30) The fourth semiconductor region is the first conductivity type semiconductor region, the intrinsic semiconductor region, or the second conductivity type semiconductor region. A photoelectric conversion device as described in item 29, characterized by the features described herein. (Item 31) The first semiconductor region and the second semiconductor region have an impurity concentration of 1 × 10⁻¹⁶ of the first conductivity type. 17 cm -3 Including the region that is above, The fourth semiconductor region has an impurity concentration of 1 × 10⁻⁶ of the first conductivity type. 16 cm -3 The following areas include: A photoelectric conversion device as described in item 29, characterized by the features described herein. (Item 32) The fourth semiconductor region includes a portion located between the second semiconductor region and the third semiconductor region. A photoelectric conversion device according to any one of items 29 to 31, characterized by the features described herein. (Item 33) The fifth semiconductor region is arranged so as not to surround the first semiconductor region. A photoelectric conversion device according to any one of items 27 to 32, characterized by the features described herein. (Item 34) The fifth semiconductor region is arranged so as not to surround the first semiconductor region and the second semiconductor region. A photoelectric conversion device according to any one of items 27 to 32, characterized by the features described herein. (Item 35) The dimensions of the second semiconductor region in the thickness direction of the semiconductor layer are 0.8 times or more and less than 2 times the dimensions of the first semiconductor region in the thickness direction. A photoelectric conversion device according to any one of items 20 to 34, characterized by the features described herein. (Item 36) The first semiconductor region and the second semiconductor region include portions whose width in a direction parallel to the first surface narrows toward the first surface. A photoelectric conversion device according to any one of items 20 to 35, characterized in that it is a photoelectric conversion device. (Item 37) The second semiconductor region has a ring shape, A photoelectric conversion device according to any one of items 20 to 35, characterized in that it is a photoelectric conversion device. (Item 38) A photoelectric converter described in any one of items 1 to 37, A signal processing unit that processes the signal output by the aforementioned photoelectric converter, A photoelectric conversion system characterized by comprising the following features. (others) The invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention.

Claims

1. A photoelectric conversion device having a semiconductor layer having a first surface and a second surface, The semiconductor layer includes a first semiconductor region of a first conductivity type extending from the first surface toward the second surface, a second semiconductor region of the first conductivity type disposed between the first semiconductor region and the second surface so as to be in contact with the first semiconductor region, and a third semiconductor region of the second conductivity type disposed between the second semiconductor region and the second surface. The width of the second semiconductor region in the direction parallel to the first plane is greater than the width of the first semiconductor region in the direction parallel to the first plane, and less than the width of the third semiconductor region in the direction parallel to the first plane. A photoelectric conversion device characterized by the following features.

2. The width of the second semiconductor region in a direction parallel to the first surface is at least twice and no more than four times the width of the first semiconductor region in a direction parallel to the first surface. The photoelectric conversion device according to feature 1.

3. The semiconductor layer further includes a fourth semiconductor region which includes a portion disposed between the second semiconductor region and the first surface so as to surround the first semiconductor region. The impurity concentration of the first conductivity type in the fourth semiconductor region is lower than the impurity concentration of the first conductivity type in the first and second semiconductor regions. The photoelectric conversion device according to feature 1.

4. The fourth semiconductor region is the first conductivity type semiconductor region, the intrinsic semiconductor region, or the second conductivity type semiconductor region. The photoelectric conversion device according to feature 3.

5. The first semiconductor region and the second semiconductor region have an impurity concentration of 1 × 10⁻¹⁶ of the first conductivity type. １７ cm －３ Including the region that is above, The fourth semiconductor region has an impurity concentration of 1 × 10⁻⁶ of the first conductivity type. １６ cm －３ The following areas include: The photoelectric conversion device according to feature 3.

6. The width of the second semiconductor region in a direction parallel to the first surface is at least twice the width of the first semiconductor region in a direction parallel to the first surface. The photoelectric conversion device according to feature 3.

7. The width of the second semiconductor region in a direction parallel to the first surface is no more than four times the width of the first semiconductor region in a direction parallel to the first surface. The photoelectric conversion device according to feature 6.

8. Having multiple pixels, Each pixel has an active region including the first semiconductor region, the second semiconductor region, and the third semiconductor region. The active region includes a seventh semiconductor region disposed between the third semiconductor region and the second surface. The semiconductor layer includes a pixel isolation portion disposed between adjacent pixels and a fifth semiconductor region of the second conductivity type disposed between the pixel isolation portion and the seventh semiconductor region. The photoelectric conversion device according to feature 1.

9. The third semiconductor region extends so as to be in contact with the fifth semiconductor region. The photoelectric conversion device according to feature 8.

10. The semiconductor layer further includes a fourth semiconductor region disposed between the first surface and the third semiconductor region so as to surround the sides of the first and second semiconductor regions, wherein the impurity concentration of the first conductivity type in the fourth semiconductor region is lower than the impurity concentration of the first conductivity type in the first and second semiconductor regions. The photoelectric conversion device according to feature 8.

11. The fourth semiconductor region is the first conductivity type semiconductor region, the intrinsic semiconductor region, or the second conductivity type semiconductor region. The photoelectric conversion device according to feature 10.

12. The first semiconductor region and the second semiconductor region have an impurity concentration of 1 × 10⁻¹⁶ of the first conductivity type. １７ cm －３ Including the region that is above, The fourth semiconductor region has an impurity concentration of 1 × 10⁻⁶ of the first conductivity type. １６ cm －３ The following areas include: The photoelectric conversion device according to feature 10.

13. The fourth semiconductor region includes a portion located between the second semiconductor region and the third semiconductor region. The photoelectric conversion device according to feature 10.

14. The fifth semiconductor region is arranged so as not to surround the first semiconductor region. The photoelectric conversion device according to feature 8.

15. The fifth semiconductor region is arranged so as not to surround the first semiconductor region and the second semiconductor region. The photoelectric conversion device according to feature 8.

16. The width of the second semiconductor region in a direction parallel to the first plane is smaller than the distance between the second semiconductor region and the pixel separation portion in a direction parallel to the first plane. The photoelectric conversion device according to feature 8.

17. The dimensions of the second semiconductor region in the thickness direction of the semiconductor layer are 0.8 times or more and less than 2 times the dimensions of the first semiconductor region in the thickness direction of the semiconductor layer. The photoelectric conversion device according to feature 1.

18. The first semiconductor region and the second semiconductor region include portions whose width in a direction parallel to the first surface narrows toward the first surface. The photoelectric conversion device according to feature 1.

19. The second semiconductor region has a ring shape, The photoelectric conversion device according to feature 1.

20. A photoelectric conversion device having a semiconductor layer having a first surface and a second surface, The semiconductor layer includes a first semiconductor region of a first conductivity type extending from the first surface toward the second surface, a second semiconductor region of the first conductivity type disposed between the first semiconductor region and the second surface so as to be in contact with the first semiconductor region, a third semiconductor region of the second conductivity type disposed between the second semiconductor region and the second surface, and a pixel separation portion surrounding the first semiconductor region, the second semiconductor region, and the third semiconductor region. The width of the second semiconductor region in a direction parallel to the first plane is smaller than the distance between the second semiconductor region and the pixel separation portion in a direction parallel to the first plane. A photoelectric conversion device characterized by the following features.

21. The width of the second semiconductor region in a direction parallel to the first surface is at least twice and no more than four times the width of the first semiconductor region in a direction parallel to the first surface. The photoelectric conversion device according to feature 20.

22. The semiconductor layer further includes a fourth semiconductor region which includes a portion disposed between the second semiconductor region and the first surface so as to surround the first semiconductor region. The impurity concentration of the first conductivity type in the fourth semiconductor region is lower than the impurity concentration of the first conductivity type in the first and second semiconductor regions. The photoelectric conversion device according to feature 20.

23. The fourth semiconductor region is the first conductivity type semiconductor region, the intrinsic semiconductor region, or the second conductivity type semiconductor region. The photoelectric conversion device according to feature 22.

24. The first semiconductor region and the second semiconductor region have an impurity concentration of the first conductivity type of 1×10 １７ cm －３ that includes a region equal to or higher than The fourth semiconductor region has an impurity concentration of 1 × 10⁻⁶ of the first conductivity type. １６ cm －３ The following areas include: The photoelectric conversion device according to feature 22.

25. The width of the second semiconductor region in a direction parallel to the first surface is at least twice the width of the first semiconductor region in a direction parallel to the first surface. The photoelectric conversion device according to feature 22.

26. The width of the second semiconductor region in a direction parallel to the first surface is no more than four times the width of the first semiconductor region in a direction parallel to the first surface. The photoelectric conversion device according to feature 25.

27. Having multiple pixels, Each pixel has an active region including the first semiconductor region, the second semiconductor region, and the third semiconductor region. The active region includes a seventh semiconductor region disposed between the third semiconductor region and the second surface. The semiconductor layer includes a fifth semiconductor region of the second conductivity type disposed between the pixel separation portion and the seventh semiconductor region. The photoelectric conversion device according to feature 20.

28. The third semiconductor region extends so as to be in contact with the fifth semiconductor region. The photoelectric conversion device according to feature 27.

29. The semiconductor layer further includes a fourth semiconductor region disposed between the first surface and the third semiconductor region so as to surround the sides of the first and second semiconductor regions, wherein the impurity concentration of the first conductivity type in the fourth semiconductor region is lower than the impurity concentration of the first conductivity type in the first and second semiconductor regions. The photoelectric conversion device according to feature 27.

30. The fourth semiconductor region is the first conductivity type semiconductor region, the intrinsic semiconductor region, or the second conductivity type semiconductor region. The photoelectric conversion device according to feature 29.

31. The first semiconductor region and the second semiconductor region have an impurity concentration of 1 × 10⁻¹⁶ of the first conductivity type. １７ cm －３ Including the region that is above, The fourth semiconductor region has an impurity concentration of 1 × 10⁻⁶ of the first conductivity type. １６ cm －３ The following areas include: The photoelectric conversion device according to feature 29.

32. The fourth semiconductor region includes a portion located between the second semiconductor region and the third semiconductor region. The photoelectric conversion device according to feature 29.

33. The fifth semiconductor region is arranged so as not to surround the first semiconductor region. The photoelectric conversion device according to feature 27.

34. The fifth semiconductor region is arranged so as not to surround the first semiconductor region and the second semiconductor region. The photoelectric conversion device according to feature 27.

35. The dimensions of the second semiconductor region in the thickness direction of the semiconductor layer are 0.8 times or more and less than 2 times the dimensions of the first semiconductor region in the thickness direction of the semiconductor layer. The photoelectric conversion device according to feature 20.

36. The first semiconductor region and the second semiconductor region include portions whose width in a direction parallel to the first surface narrows toward the first surface. The photoelectric conversion device according to feature 20.

37. The second semiconductor region has a ring shape, The photoelectric conversion device according to feature 20.

38. A photoelectric conversion device according to any one of claims 1 to 37, A signal processing unit that processes the signal output by the aforementioned photoelectric converter, A photoelectric conversion system characterized by comprising the following features.

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