WO2022158170A1

WO2022158170A1 - Photodetector and electronic device

Info

Publication number: WO2022158170A1
Application number: PCT/JP2021/045945
Authority: WO
Inventors: 博亮村上
Original assignee: ソニーセミコンダクタソリューションズ株式会社
Priority date: 2021-01-21
Filing date: 2021-12-14
Publication date: 2022-07-28
Also published as: JP2022112252A

Abstract

A photodetector according to the present disclosure is provided with a light receiving pixel (2) that has a photodiode (20). The photodiode (20) comprises a first impurity region (21) of a first conductivity type, a capacity expansion region (30) that is arranged lateral to the first impurity region (21), and a second impurity region (22) of a second conductivity type, said second impurity region being arranged so as to surround the first impurity region (21) and the capacity expansion region (30). The capacity expansion region (30) is formed by alternately stacking a third impurity region (31) of the first conductivity type and a fourth impurity region (32) of the second conductivity type in the thickness direction of a substrate (11).

Description

Photodetectors and electronic devices

The present disclosure relates to photodetectors and electronic devices.

Conventionally, image sensors having photodiodes such as CCD (Charge-Coupled Device) image sensors and CMOS (Complementary Metal Oxide Semiconductor) image sensors have been widely used.

In such an image sensor, the dynamic range and SN ratio can be improved by increasing the saturation signal charge amount (Qs) of the photodiode. For example, there is known a technique capable of increasing the saturation signal charge amount of the photodiode by making the PN junction surface inside the photodiode concave (see, for example, Patent Document 1).

JP-A-2005-332925

However, the conventional technology described above has room for further improvement in terms of increasing the saturation signal charge amount of the photodiode.

Therefore, the present disclosure proposes a photodetector and an electronic device capable of increasing the saturation signal charge amount of a photodiode.

According to the present disclosure, a photodetector is provided. The photodetector includes light-receiving pixels having photodiodes. The photodiode includes a first conductivity type first impurity region, a capacitance enlarging region arranged laterally of the first impurity region, and arranged to surround the first impurity region and the capacitance enlarging region. and a second impurity region of the second conductivity type. The capacitance expansion region is formed by alternately stacking a first-conductivity-type third impurity region and a second-conductivity-type fourth impurity region along the thickness direction of the substrate.

1 is a system configuration diagram showing a schematic configuration example of a photodetector according to an embodiment of the present disclosure; FIG. 2 is a plan view schematically showing the configuration of light receiving pixels according to the embodiment of the present disclosure; FIG. 3 is a cross-sectional view taken along line A1-A1 shown in FIG. 2; FIG. 3 is a cross-sectional view taken along line A2-A2 shown in FIG. 2; FIG. FIG. 7 is a plan view schematically showing the configuration of a light receiving pixel according to Modification 1 of the embodiment of the present disclosure; 6 is a cross-sectional view taken along line B1-B1 shown in FIG. 5; FIG. 6 is a cross-sectional view taken along line B2-B2 shown in FIG. 5; FIG. FIG. 7 is a plan view schematically showing the configuration of a light receiving pixel according to Modification 2 of the embodiment of the present disclosure; 9 is a cross-sectional view taken along line C1-C1 shown in FIG. 8. FIG. 9 is a cross-sectional view taken along line C2-C2 shown in FIG. 8. FIG. FIG. 10 is a plan view schematically showing the configuration of a light receiving pixel according to Modification 3 of the embodiment of the present disclosure; 12 is a cross-sectional view taken along line D1-D1 shown in FIG. 11; FIG. 12 is a cross-sectional view taken along line D2-D2 shown in FIG. 11; FIG. FIG. 10 is a plan view schematically showing the configuration of a light receiving pixel according to Modification 4 of the embodiment of the present disclosure; 15 is a cross-sectional view taken along line E1-E1 shown in FIG. 14; FIG. 15 is a cross-sectional view taken along line E2-E2 shown in FIG. 14; FIG. 1 is a block diagram showing a configuration example of an imaging device as an electronic device to which technology according to the present disclosure is applied; FIG. 1 is a block diagram showing an example of a schematic configuration of a vehicle control system; FIG. FIG. 4 is an explanatory diagram showing an example of installation positions of an outside information detection unit and an imaging unit; 1 is a diagram showing an example of a schematic configuration of an endoscopic surgery system; FIG. 3 is a block diagram showing an example of functional configurations of a camera head and a CCU; FIG.

Below, each embodiment of the present disclosure will be described in detail based on the drawings. In addition, in each of the following embodiments, the same reference numerals are given to the same parts to omit redundant explanations.

In such an image sensor, the dynamic range and SN ratio can be improved by increasing the saturation signal charge amount (Qs) of the photodiode. For example, a technique is known in which the saturation signal charge amount of the photodiode can be increased by forming the PN junction surface inside the photodiode into a concave shape.

Therefore, it is expected to realize a technology that can overcome the above-mentioned problems and increase the saturation signal charge amount of the photodiode.

[Structure of solid-state imaging device]
First, the configuration of a solid-state imaging device 1 according to an embodiment will be described with reference to FIG. FIG. 1 is a system configuration diagram showing a schematic configuration example of a solid-state imaging device 1 according to an embodiment of the present disclosure. The solid-state imaging device 1 is an example of a photodetector.

As shown in FIG. 1, the solid-state imaging device 1 according to the embodiment is configured with a pixel region 3 and a peripheral circuit section. In the pixel region 3, light-receiving pixels 2 including a plurality of photodiodes 20 (see FIG. 2) are regularly arranged two-dimensionally on a substrate 11 made of a semiconductor (for example, silicon).

The light receiving pixel 2 has a photodiode 20, which is a photoelectric conversion element, and a plurality of pixel transistors (so-called MOS transistors). A plurality of pixel transistors can be composed of, for example, three transistors: a transfer transistor 40 (see FIG. 2), a reset transistor, and an amplification transistor.

In addition, the plurality of pixel transistors can also be configured with four transistors by adding a selection transistor. Since the equivalent circuit of the unit pixel is the same as usual, detailed description is omitted.

The light-receiving pixels 2 according to the embodiment can also have a shared pixel structure. This pixel-sharing structure includes a plurality of photodiodes 20, a plurality of transfer transistors 40, one shared floating diffusion 50 (see FIG. 2), and one shared pixel transistor (not shown). consists of

The peripheral circuit section includes a vertical drive circuit 4, a column signal processing circuit 5, a horizontal drive circuit 6, an output circuit 7, a control circuit 8, and the like.

The control circuit 8 receives an input clock and data instructing an operation mode, etc., and outputs data such as internal information of the solid-state imaging device. That is, the control circuit 8 generates a clock signal and a control signal that serve as a reference for the operation of the vertical drive circuit 4, the column signal processing circuit 5, the horizontal drive circuit 6, etc. based on the vertical synchronization signal, the horizontal synchronization signal, and the master clock. do.

The control circuit 8 then inputs these signals to the vertical drive circuit 4, the column signal processing circuit 5, the horizontal drive circuit 6, and the like.

The vertical drive circuit 4 is composed of, for example, a shift register, selects a pixel drive wiring, supplies a pulse for driving the pixels to the selected pixel drive wiring, and drives the pixels row by row. That is, the vertical drive circuit 4 sequentially selectively scans the light-receiving pixels 2 in the pixel region 3 row by row in the vertical direction.

Then, the vertical drive circuit 4 supplies the column signal processing circuit 5 with a pixel signal based on the signal charge generated according to the amount of light received by the photodiode 20 , which is the photoelectric conversion element of each light receiving pixel 2 , through the vertical signal line 9 . .

The column signal processing circuit 5 is arranged, for example, for each column of the light receiving pixels 2, and performs signal processing such as noise removal on the signals output from the light receiving pixels 2 of one row for each pixel column. That is, the column signal processing circuit 5 performs signal processing such as CDS (Correlated Double Sampling) for removing fixed pattern noise unique to the light receiving pixels 2, signal amplification, and AD conversion.

A horizontal selection switch (not shown) is connected between the output stage of the column signal processing circuit 5 and the horizontal signal line 10 .

The horizontal driving circuit 6 is composed of, for example, a shift register, and sequentially outputs horizontal scanning pulses to select each of the column signal processing circuits 5 in turn, and outputs pixel signals from each of the column signal processing circuits 5 to the horizontal signal line. output to 10.

The output circuit 7 performs signal processing on the signals sequentially supplied from each of the column signal processing circuits 5 through the horizontal signal line 10 and outputs the processed signals. For example, only buffering may be performed, or black level adjustment, column variation correction, and various digital signal processing may be performed. The input/output terminal 12 exchanges signals with the outside.

[Configuration of light receiving pixel]
Next, a detailed configuration of the light receiving pixel 2 according to the embodiment will be described with reference to FIGS. 2 to 4. FIG. FIG. 2 is a plan view schematically showing the configuration of the light receiving pixel 2 according to the embodiment of the present disclosure. 3 is a cross-sectional view taken along line A1-A1 shown in FIG. 2, and FIG. 4 is a cross-sectional view taken along line A2-A2 shown in FIG.

It should be noted that the drawings of the present disclosure show an XYZ coordinate system for easy understanding. The Z-axis direction corresponds to the thickness direction of the substrate 11 (see FIG. 1). The X-axis direction and the Y-axis direction correspond to the planar direction of the substrate 11 . Further, in the present disclosure, light from the subject enters from the Z-axis negative direction side or the Z-axis positive direction side.

As shown in FIGS. 2 to 4, the light-receiving pixel 2 according to the embodiment includes a photodiode 20, a transfer transistor 40, and a floating diffusion 50. FIG.

In addition, the photodiode 20 has a first conductivity type first impurity region 21 , a second conductivity type second impurity region 22 , and a capacitance expansion region 30 . First impurity region 21 is, for example, a high-concentration N-type impurity region.

The capacitance expansion region 30 is provided to increase the saturation signal charge amount of the photodiode 20, and is located on the side of the first impurity region 21 (that is, adjacent to the first impurity region 21 in the plane direction of the substrate 11). ), and is arranged to be in contact with the first impurity region 21 .

Also, in the present disclosure, as shown in FIGS. 2 to 4, the first impurity region 21 and the capacitance-enlarging region 30 are integrally formed in a substantially rectangular parallelepiped shape. Then, the second impurity region 22 is arranged so as to surround the substantially rectangular parallelepiped first impurity region 21 and the capacitance enlarging region 30 . Second impurity region 22 is, for example, a high-concentration P-type impurity region.

Here, as shown in FIGS. 3 and 4, the capacitance expansion region 30 according to the embodiment includes a third impurity region 31 of a first conductivity type (N-type in the embodiment) and a second conductivity type (N-type in the embodiment). P-type) fourth impurity regions 32 are alternately laminated along the thickness direction of the substrate 11 . Thereby, the area of the PN junction surface inside the photodiode 20 can be enlarged.

Then, the saturation signal charge amount of the photodiode 20 increases as the area of the PN junction surface inside the photodiode 20 increases. That is, in the embodiment, the saturated signal charge amount of the photodiode 20 can be increased by providing the capacitance enlarging region 30 in the photodiode 20 .

The transfer transistor 40 has a function of transferring signal charges (here, electrons) generated and accumulated in the photodiode 20 to the floating diffusion 50 . Such a transfer transistor 40 is arranged adjacent to the first impurity region 21 of the photodiode 20 .

Also, as shown in FIG. 4, the transfer transistor 40 has a gate electrode 41 and an insulating layer 42 . The gate electrode 41 is arranged adjacent to the second impurity region 22a located between the first impurity region 21 and the floating diffusion 50 with the insulating layer 42 interposed therebetween.

The insulating layer 42 is arranged between the gate electrode 41 and the second impurity region 22a. Alternatively, the insulating layer 42 may be arranged to cover the entire surface of the substrate 11, including the area between the gate electrode 41 and the second impurity region 22a, as shown in FIG. 3 and the like.

The floating diffusion 50 has a function of temporarily holding signal charges transferred from the photodiode 20 via the transfer transistor 40 . The floating diffusion 50 is composed of, for example, a high-concentration N-type impurity region.

In the embodiment, as shown in FIG. 4 and the like, the first impurity region 21 arranged on the side of the capacitance enlarging region 30 is preferably arranged between the capacitance enlarging region 30 and the transfer transistor 40 .

As a result, the signal charges generated in all the third impurity regions 31 inside the capacitance enlarging region 30 can be smoothly guided to the transfer transistor 40 through the first impurity regions 21 connected to all the third impurity regions 31. .

In other words, in the embodiment, the movement of the signal charge generated in the capacitance enlarging region 30 to the transfer transistor 40 is blocked by the P-type fourth impurity region 32 located between the capacitance enlarging region 30 and the transfer transistor 40 . can be suppressed.

Therefore, according to the embodiment, the transfer efficiency of signal charges accumulated in the photodiode 20 can be improved.

In addition, in the embodiment, as shown in FIG. 2, the capacitance increasing regions 30 are preferably arranged in a comb shape in plan view. For example, as shown in FIG. 2, the transfer transistor 40 is arranged on one side (upper side in FIG. 2) of the first impurity region 21 which is rectangular in plan view, and the other three sides are arranged inside the first impurity region 21. A plurality of capacitance-enlarging regions 30 may be arranged in a comb shape so as to protrude toward the edge.

Thereby, the signal charges generated in the capacitance-enlarging regions 30 can be guided to the transfer transistor 40 through the first impurity regions 21 located between the adjacent capacitance-enlarging regions 30 as well.

Therefore, according to the embodiment, the transfer efficiency of signal charges accumulated in the photodiode 20 can be further improved.

In addition, in the embodiment, by arranging the capacitance-enlarging region 30 in a comb shape, in addition to the interface between the third impurity region 31 and the fourth impurity region 32, the side surface of the fourth impurity region 32 (that is, the first A PN junction surface can also be formed at the interface with the impurity region 21).

Therefore, according to the embodiment, since the area of the PN junction surface in the photodiode 20 can be further increased, the saturation signal charge amount of the photodiode 20 can be further increased.

In addition, in the embodiment, as shown in FIG. 2, it is preferable to arrange the comb-shaped capacitance-enlarging region 30 toward the inside of the first impurity region 21 . As a result, the signal charges transferred through the first impurity regions 21 located between the adjacent capacitance-enlarging regions 30 can be more smoothly led to the transfer transistor 40 .

Also, in the embodiment, as shown in FIGS. 3 and 4, it is preferable that the width of the capacitance expansion region 30 gradually widens as the distance from the transfer transistor 40 increases. As a result, movement of signal charges generated in the capacitance expansion region 30 located deep away from the transfer transistor 40 to the transfer transistor 40 is prevented from being hindered by the P-type fourth impurity region 32 located deep. can do.

In the embodiment, as shown in FIG. 2, in the light-receiving pixel 2, the plurality of capacitance-enlarging regions 30 may be arranged symmetrically in plan view, and the transfer transistor 40 may be arranged on the axis of symmetry. .

As a result, signal charges can be led to the transfer transistors 40 substantially equally from all the capacitance-enlarging regions 30 arranged inside the photodiodes 20 . Therefore, according to the embodiment, the transfer efficiency of signal charges accumulated in the photodiode 20 can be further improved.

Note that the capacitance expansion region 30 according to the embodiment can be formed, for example, by implanting donor ions and acceptor ions in layers from the surface of the substrate 11 with acceleration energies changed in multiple stages.

Further, in the embodiment, the impurity concentration of the third impurity region 31 included in the capacitance expansion region 30 is preferably lower than the impurity concentration of the first impurity region 21 of the same conductivity type. Similarly, the impurity concentration of the fourth impurity region 32 included in the capacitance expansion region 30 is preferably lower than the impurity concentration of the second impurity region 22 of the same conductivity type.

For example, assume that the impurity concentration of the third impurity region 31 is higher than or equal to the impurity concentration of the first impurity region 21 and the impurity concentration of the fourth impurity region 32 is higher than or equal to that of the second impurity region 22 .

In this case, the potential distribution of the PN junction surface between the third impurity region 31 and the fourth impurity region 32 is greatly disturbed due to the influence of impurity scattering caused by ion implantation or the like, and thus the signal charge transfer efficiency is reduced. It may get worse.

However, in the embodiment, the impurity concentration of the third impurity region 31 is lower than that of the first impurity region 21 and the impurity concentration of the fourth impurity region 32 is lower than that of the second impurity region 22 . Therefore, it is possible to prevent the potential distribution of the PN junction surface between the third impurity region 31 and the fourth impurity region 32 from being greatly disturbed.

[various modifications]
<Modification 1>
Next, various modifications of the embodiment will be described with reference to FIGS. 5 to 16. FIG. FIG. 5 is a plan view schematically showing the configuration of the light receiving pixel 2 according to Modification 1 of the embodiment of the present disclosure. 6 is a cross-sectional view taken along line B1-B1 shown in FIG. 5, and FIG. 7 is a cross-sectional view taken along line B2-B2 shown in FIG.

As shown in FIG. 5, in the light-receiving pixel 2 according to Modification 1, the capacitance-enlarging region 30 has a tapered shape in which the width gradually narrows as it approaches the transfer transistor 40 in plan view.

As a result, since the opening of the first impurity region 21 positioned between the adjacent capacitance enlarging regions 30 can be widened, signal charges can be smoothly guided to the transfer transistor 40 through the first impurity region 21 . .

Therefore, according to Modification 1, the transfer efficiency of the signal charge accumulated in the photodiode 20 can be further improved.

In the example of FIG. 5, the width of the capacitance-enhancing region 30 linearly narrows from the base end (ie, the end on the second impurity region 22 side) of the capacitance-enhancing region 30 to the tip in plan view. , the disclosure is not limited to such examples.

For example, the width of the capacity-enlarging region 30 may be narrowed stepwise from the proximal end to the distal end. Also, from the proximal end to the distal end of the capacitance-enlarging region 30, a part of the region may be narrowed linearly, and the rest of the region may be narrowed stepwise.

<Modification 2>
FIG. 8 is a plan view schematically showing the configuration of the light receiving pixel 2 according to Modification 2 of the embodiment of the present disclosure. 9 is a cross-sectional view taken along line C1-C1 shown in FIG. 8, and FIG. 10 is a cross-sectional view taken along line C2-C2 shown in FIG.

As shown in FIG. 10, in the light-receiving pixel 2 according to Modification 2, the transfer transistor 40 is a vertical transistor. Specifically, the transfer transistor 40 of Modification 2 includes a gate electrode 41 extending along the thickness direction of the substrate 11 (see FIG. 1), an insulating layer 42 , and an insulating layer 42 arranged along the surface of the gate electrode 41 . and a membrane 43 .

Further, in Modification 2, as shown in FIG. 8 and the like, some of the plurality of capacitance enlarging regions 30 are arranged close to the transfer transistor 40 .

Specifically, in plan view, the capacitance enlarging region 30 extending from the side opposite to the side of the first impurity region 21 where the transfer transistor 40 is arranged is the first impurity region 21 where the transfer transistor 40 is arranged. extends toward one side of the A plurality of capacitance enlarging regions 30 extending toward one side of the first impurity region 21 are arranged close to the transfer transistor 40 .

By extending the capacitance enlarging region 30 so as to approach the transfer transistor 40 in this way, the area of the PN junction surface inside the capacitance enlarging region 30 is enlarged. Therefore, according to Modification 2, the saturation signal charge amount of the photodiode 20 can be further increased.

In addition, in Modification 2, by using a vertical transistor as the transfer transistor 40, signal charges generated in the capacitance expansion region 30 at a deep position away from the transfer transistor 40 move to the fourth impurity region 32 at a shallow position. can be suppressed.

Therefore, according to Modification 2, even when the capacitance expansion region 30 is extended so as to be close to the transfer transistor 40, the transfer efficiency of the signal charges accumulated in the photodiode 20 can be maintained satisfactorily.

Note that, in the modification 2, as in the above-described embodiments, in a plan view, a comb-like capacitance is expanded on two sides substantially perpendicular to one side of the first impurity region 21 where the transfer transistor 40 is arranged. A region 30 is arranged.

<Modification 3>
FIG. 11 is a plan view schematically showing the configuration of a light receiving pixel 2 according to Modification 3 of the embodiment of the present disclosure. 12 is a cross-sectional view taken along line D1-D1 shown in FIG. 11, and FIG. 13 is a cross-sectional view taken along line D2-D2 shown in FIG.

As shown in FIG. 13, in the light-receiving pixel 2 according to Modification 3, the transfer transistor 40 is a vertical transistor as in Modification 2 described above. Further, in Modification 3, as shown in FIG. 11 , some of the plurality of capacitance enlarging regions 30 are arranged close to the transfer transistor 40 .

Specifically, in a plan view, all capacitance enlarging regions 30 extend from one side of the first impurity region 21 on which the transfer transistor 40 is arranged to the first impurity region 21 on which the transfer transistor 40 is arranged. It extends toward one side of the region 21 .

Among all the capacitance enlarging regions 30 extending toward one side of the first impurity region 21 , the central capacitance enlarging region 30 is arranged close to the transfer transistor 40 .

By extending the capacitance enlarging region 30 so as to approach the transfer transistor 40 in this way, the area of the PN junction surface inside the capacitance enlarging region 30 is enlarged. Therefore, according to Modification 3, the saturated signal charge amount of the photodiode 20 can be further increased.

Further, in Modification 3, by using a vertical transistor as the transfer transistor 40, signal charges generated in the capacitance expansion region 30 at a deep position distant from the transfer transistor 40 move to the fourth impurity region 32 at a shallow position. can be suppressed.

Therefore, according to Modification 3, even when the capacitance expansion region 30 is extended so as to be close to the transfer transistor 40, the transfer efficiency of the signal charges accumulated in the photodiode 20 can be maintained satisfactorily.

<Modification 4>
FIG. 14 is a plan view schematically showing the configuration of a light receiving pixel 2 according to Modification 4 of the embodiment of the present disclosure. 15 is a cross-sectional view taken along line E1-E1 shown in FIG. 14, and FIG. 16 is a cross-sectional view taken along line E2-E2 shown in FIG.

As shown in FIG. 14 and the like, in the light-receiving pixel 2 according to Modification 4, the capacitance-enlarging region 30 is wider than the first impurity region 21 in plan view. For example, in modification 4, the first impurity region 21 is arranged in the region near the transfer transistor 40 in the region inside the second impurity region 22 in a plan view, and the capacitance enlarging region 30 is arranged in the other regions. is placed.

By arranging the capacitance enlarging region 30 in more than half of the area inside the second impurity region 22 in this way, the area of the PN junction surface inside the capacitance enlarging region 30 is further enlarged. Therefore, according to Modification 4, the saturation signal charge amount of the photodiode 20 can be further increased.

Note that although the example of FIG. 16 shows an example in which the transfer transistor 40 is configured by a planar transistor, the present disclosure is not limited to such an example, and for example, the transfer transistor 40 may be a vertical transistor. .

As a result, it is possible to prevent movement of signal charges generated in the deep capacitance-enlarging region 30 away from the transfer transistor 40 from being hindered by the shallow fourth impurity region 32 .

Therefore, according to Modification 4, even when the capacitance-enlarging region 30 is arranged in most of the region inside the second impurity region 22, the transfer efficiency of the signal charges accumulated in the photodiode 20 can be maintained satisfactorily. can.

In addition, in the embodiments and various modifications described so far, the case where the photodiode 20 is applied to the solid-state imaging device has been shown, but the device to which the photodiode 20 of the present disclosure is applied is not limited to the solid-state imaging device.

For example, the photodiode 20 of the present disclosure can also be applied to various photodetectors such as photoresistors and photomultiplier tubes.

Further, in the embodiments and various modifications described so far, the case where the first conductivity type is the N type and the second conductivity type is the P type has been described. The type may be N type.

[effect]
A photodetector (solid-state imaging device 1 ) according to the embodiment includes light-receiving pixels 2 having photodiodes 20 . In addition, the photodiode 20 includes a first conductivity type first impurity region 21 , a capacitance enlarging region 30 arranged on the side of the first impurity region 21 , and a region surrounding the first impurity region 21 and the capacitance enlarging region 30 . and a second impurity region 22 of the second conductivity type arranged in the . The capacitance expansion region 30 is formed by alternately laminating a first-conductivity-type third impurity region 31 and a second-conductivity-type fourth impurity region 32 along the thickness direction of the substrate 11 .

Thereby, the saturation signal charge amount of the photodiode 20 can be increased.

In addition, in the photodetector (solid-state imaging device 1) according to the embodiment, the light receiving pixel 2 has a transfer transistor 40 arranged adjacent to the photodiode 20. The first impurity region 21 is arranged between the capacitance enlarging region 30 and the transfer transistor 40 .

Thereby, the transfer efficiency of the signal charge accumulated in the photodiode 20 can be improved.

In addition, in the photodetector (solid-state imaging device 1) according to the embodiment, the capacitance-enlarging region 30 is arranged in a comb shape in plan view.

Thereby, the transfer efficiency of the signal charge accumulated in the photodiode 20 can be further improved.

In addition, in the photodetector (solid-state imaging device 1) according to the embodiment, the capacity expansion region 30 has a tapered shape in which the width gradually narrows as it approaches the transfer transistor 40 in plan view.

Also, in the photodetector (solid-state imaging device 1 ) according to the embodiment, the transfer transistor 40 is a vertical transistor having a gate electrode 41 extending along the thickness direction of the substrate 11 .

As a result, the transfer efficiency of the signal charge accumulated in the photodiode 20 can be maintained favorably.

In addition, in the photodetector (solid-state imaging device 1) according to the embodiment, the capacity expansion region 30 is arranged close to the transfer transistor 40, which is a vertical transistor.

Thereby, the saturation signal charge amount of the photodiode 20 can be further increased.

In addition, in the photodetector (solid-state imaging device 1) according to the embodiment, the width of the capacitance expansion region 30 gradually widens as the distance from the transfer transistor 40 increases.

In addition, in the photodetector (solid-state imaging device 1) according to the embodiment, the capacity expansion region 30 is wider than the first impurity region 21 in plan view.

[Electronics]
The solid-state imaging device 1 as described above is applied to various electronic devices such as imaging systems such as digital still cameras and digital video cameras, mobile phones with imaging functions, and other devices with imaging functions. be able to.

FIG. 17 is a block diagram showing a configuration example of an imaging device mounted on an electronic device.

As shown in FIG. 17, the imaging device 101 includes an optical system 102, a solid-state imaging device 103, and a DSP (Digital Signal Processor) 104. Further, the imaging device 101 is configured by connecting a DSP 104, a display device 105, an operation system 106, a memory 108, a recording device 109, and a power supply system 110 via a bus 107, and is capable of capturing still images and moving images. be.

The optical system 102 includes one or more lenses, guides image light (incident light) from a subject to the solid-state imaging device 103, and forms an image on the light receiving surface (sensor section) of the solid-state imaging device 103. Let

As the solid-state imaging device 103, the solid-state imaging device 1 having any of the configuration examples described above is applied. Electrons are accumulated in the solid-state imaging device 103 for a certain period of time according to the image formed on the light receiving surface via the optical system 102 . A signal corresponding to the electrons accumulated in the solid-state imaging device 103 is supplied to the DSP 104 .

The DSP 104 performs various signal processing on the signal from the solid-state imaging device 103 to obtain an image, and temporarily stores the image data in the memory 108 . The image data stored in the memory 108 is recorded in the recording device 109 or supplied to the display device 105 to display the image. Further, the operation system 106 receives various operations by the user and supplies operation signals to each block of the imaging apparatus 101 , and the power supply system 110 supplies electric power necessary for driving each block of the imaging apparatus 101 .

In the imaging apparatus 101 configured as described above, by applying the above-described solid-state imaging device 1 as the solid-state imaging device 103, the saturation signal charge amount of the photodiode 20 can be increased, and the dynamic range and the SN ratio can be improved.

[Example of application to a moving object]
The technology (the present technology) according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure is implemented as a device mounted on any type of moving object such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility, airplanes, drones, ships, and robots. may

FIG. 18 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology according to the present disclosure can be applied.

A vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in FIG. 18, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an exterior information detection unit 12030, an interior information detection unit 12040, and an integrated control unit 12050. Also, as the functional configuration of the integrated control unit 12050, a microcomputer 12051, an audio/image output unit 12052, and an in-vehicle network I/F (Interface) 12053 are illustrated.

The drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various programs. For example, the driving system control unit 12010 includes a driving force generator for generating driving force of the vehicle such as an internal combustion engine or a driving motor, a driving force transmission mechanism for transmitting the driving force to the wheels, and a steering angle of the vehicle. It functions as a control device such as a steering mechanism to adjust and a brake device to generate braking force of the vehicle.

The body system control unit 12020 controls the operation of various devices equipped on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a keyless entry system, a smart key system, a power window device, or a control device for various lamps such as headlamps, back lamps, brake lamps, winkers or fog lamps. In this case, the body system control unit 12020 can receive radio waves transmitted from a portable device that substitutes for a key or signals from various switches. The body system control unit 12020 receives the input of these radio waves or signals and controls the door lock device, power window device, lamps, etc. of the vehicle.

The vehicle exterior information detection unit 12030 detects information outside the vehicle in which the vehicle control system 12000 is installed. For example, the vehicle exterior information detection unit 12030 is connected with an imaging section 12031 . The vehicle exterior information detection unit 12030 causes the imaging unit 12031 to capture an image of the exterior of the vehicle, and receives the captured image. The vehicle exterior information detection unit 12030 may perform object detection processing or distance detection processing such as people, vehicles, obstacles, signs, or characters on the road surface based on the received image.

The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according to the amount of received light. The imaging unit 12031 can output the electric signal as an image, and can also output it as distance measurement information. Also, the light received by the imaging unit 12031 may be visible light or non-visible light such as infrared rays.

The in-vehicle information detection unit 12040 detects in-vehicle information. The in-vehicle information detection unit 12040 is connected to, for example, a driver state detection section 12041 that detects the state of the driver. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 detects the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041. It may be calculated, or it may be determined whether the driver is dozing off.

The microcomputer 12051 calculates control target values for the driving force generator, the steering mechanism, or the braking device based on information on the inside and outside of the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, and controls the drive system control unit. A control command can be output to 12010 . For example, the microcomputer 12051 implements ADAS (Advanced Driver Assistance System) functions including collision avoidance or shock mitigation, follow-up driving based on inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, or vehicle lane deviation warning. Cooperative control can be performed for the purpose of

Further, the microcomputer 12051 controls the driving force generator, the steering mechanism, the braking device, etc. based on the information about the vehicle surroundings acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, so that the driver's Cooperative control can be performed for the purpose of autonomous driving, etc., in which vehicles autonomously travel without depending on operation.

Also, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the information detection unit 12030 outside the vehicle. For example, the microcomputer 12051 controls the headlamps according to the position of the preceding vehicle or the oncoming vehicle detected by the vehicle exterior information detection unit 12030, and performs coordinated control aimed at anti-glare such as switching from high beam to low beam. It can be carried out.

The audio/image output unit 12052 transmits at least one of audio and/or image output signals to an output device capable of visually or audibly notifying the passengers of the vehicle or the outside of the vehicle. In the example of FIG. 18, an audio speaker 12061, a display unit 12062, and an instrument panel 12063 are illustrated as output devices. The display unit 12062 may include at least one of an on-board display and a head-up display, for example.

FIG. 19 is a diagram showing an example of the installation position of the imaging unit 12031. FIG.

In FIG. 19, the imaging unit 12031 has

imaging units

12101, 12102, 12103, 12104, and 12105.

The

imaging units

12101, 12102, 12103, 12104, and 12105 are provided at positions such as the front nose, side mirrors, rear bumper, back door, and windshield of the vehicle 12100, for example. An imaging unit 12101 provided in the front nose and an imaging unit 12105 provided above the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100 .

Imaging units

12102 and 12103 provided in the side mirrors mainly acquire side images of the vehicle 12100 . An imaging unit 12104 provided in the rear bumper or back door mainly acquires an image behind the vehicle 12100 . The imaging unit 12105 provided above the windshield in the passenger compartment is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, and the like.

Note that FIG. 19 shows an example of the imaging range of the imaging units 12101 to 12104. FIG. The imaging range 12111 indicates the imaging range of the imaging unit 12101 provided in the front nose, the imaging ranges 12112 and 12113 indicate the imaging ranges of the

imaging units

12102 and 12103 provided in the side mirrors, respectively, and the imaging range 12114 The imaging range of an imaging unit 12104 provided on the rear bumper or back door is shown. For example, by superimposing the image data captured by the imaging units 12101 to 12104, a bird's-eye view image of the vehicle 12100 viewed from above can be obtained.

At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.

For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 determines the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and changes in this distance over time (relative velocity with respect to the vehicle 12100). , it is possible to extract, as the preceding vehicle, the closest three-dimensional object on the traveling path of the vehicle 12100, which runs at a predetermined speed (for example, 0 km/h or more) in substantially the same direction as the vehicle 12100. can. Furthermore, the microcomputer 12051 can set the inter-vehicle distance to be secured in advance in front of the preceding vehicle, and can perform automatic braking control (including following stop control) and automatic acceleration control (including following start control). In this way, cooperative control can be performed for the purpose of automatic driving in which the vehicle autonomously travels without depending on the operation of the driver.

For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 converts three-dimensional object data related to three-dimensional objects to other three-dimensional objects such as motorcycles, ordinary vehicles, large vehicles, pedestrians, and utility poles. It can be classified and extracted and used for automatic avoidance of obstacles. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into those that are visible to the driver of the vehicle 12100 and those that are difficult to see. Then, the microcomputer 12051 judges the collision risk indicating the degree of danger of collision with each obstacle, and when the collision risk is equal to or higher than the set value and there is a possibility of collision, the obstacle is detected through the audio speaker 12061 and the display unit 12062. By outputting an alarm to the driver via the drive system control unit 12010 and performing forced deceleration and avoidance steering via the drive system control unit 12010, driving support for collision avoidance can be performed.

At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether or not the pedestrian exists in the captured images of the imaging units 12101 to 12104 . Such recognition of a pedestrian is performed by, for example, a procedure for extracting feature points in images captured by the imaging units 12101 to 12104 as infrared cameras, and performing pattern matching processing on a series of feature points indicating the outline of an object to determine whether or not the pedestrian is a pedestrian. This is done by a procedure that determines When the microcomputer 12051 determines that a pedestrian exists in the captured images of the imaging units 12101 to 12104 and recognizes the pedestrian, the audio image output unit 12052 outputs a rectangular outline for emphasis to the recognized pedestrian. is superimposed on the display unit 12062 . Also, the audio/image output unit 12052 may control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.

An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging unit 12031 among the configurations described above. Specifically, the solid-state imaging device 1 in FIG. 1 can be applied to the imaging section 12031 . By applying the technology according to the present disclosure to the imaging unit 12031, a high-quality image with improved dynamic range and SN ratio can be obtained from the imaging unit 12031.

[Example of application to an endoscopic surgery system]
The technology (the present technology) according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

FIG. 20 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (this technology) can be applied.

FIG. 20 shows an operator (doctor) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgery system 11000 . As illustrated, an endoscopic surgery system 11000 includes an endoscope 11100, other surgical instruments 11110 such as a pneumoperitoneum tube 11111 and an energy treatment instrument 11112, and a support arm device 11120 for supporting the endoscope 11100. , and a cart 11200 loaded with various devices for endoscopic surgery.

An endoscope 11100 is composed of a lens barrel 11101 whose distal end is inserted into the body cavity of a patient 11132 and a camera head 11102 connected to the proximal end of the lens barrel 11101 . In the illustrated example, an endoscope 11100 configured as a so-called rigid scope having a rigid lens barrel 11101 is illustrated, but the endoscope 11100 may be configured as a so-called flexible scope having a flexible lens barrel. good.

The tip of the lens barrel 11101 is provided with an opening into which the objective lens is fitted. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel 11101 by a light guide extending inside the lens barrel 11101, where it reaches the objective. Through the lens, the light is irradiated toward the observation object inside the body cavity of the patient 11132 . Note that the endoscope 11100 may be a straight scope, a perspective scope, or a side scope.

An optical system and an imaging element are provided inside the camera head 11102, and the reflected light (observation light) from the observation target is focused on the imaging element by the optical system. The imaging device photoelectrically converts the observation light to generate an electrical signal corresponding to the observation light, that is, an image signal corresponding to the observation image. The image signal is transmitted to a camera control unit (CCU: Camera Control Unit) 11201 as RAW data.

The CCU 11201 is composed of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and controls the operations of the endoscope 11100 and the display device 11202 in an integrated manner. Further, the CCU 11201 receives an image signal from the camera head 11102 and performs various image processing such as development processing (demosaicing) for displaying an image based on the image signal.

The display device 11202 displays an image based on an image signal subjected to image processing by the CCU 11201 under the control of the CCU 11201 .

The light source device 11203 is composed of a light source such as an LED (light emitting diode), for example, and supplies the endoscope 11100 with irradiation light for imaging a surgical site or the like.

The input device 11204 is an input interface for the endoscopic surgery system 11000. The user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204 . For example, the user inputs an instruction or the like to change the imaging conditions (type of irradiation light, magnification, focal length, etc.) by the endoscope 11100 .

The treatment instrument control device 11205 controls driving of the energy treatment instrument 11112 for tissue cauterization, incision, blood vessel sealing, or the like. The pneumoperitoneum device 11206 inflates the body cavity of the patient 11132 for the purpose of securing the visual field of the endoscope 11100 and securing the operator's working space, and injects gas into the body cavity through the pneumoperitoneum tube 11111. send in. The recorder 11207 is a device capable of recording various types of information regarding surgery. The printer 11208 is a device capable of printing various types of information regarding surgery in various formats such as text, images, and graphs.

It should be noted that the light source device 11203 that supplies the endoscope 11100 with irradiation light for photographing the surgical site can be composed of, for example, a white light source composed of an LED, a laser light source, or a combination thereof. When a white light source is configured by a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high accuracy. It can be carried out. Further, in this case, the observation target is irradiated with laser light from each of the RGB laser light sources in a time-division manner, and by controlling the drive of the imaging element of the camera head 11102 in synchronization with the irradiation timing, each of RGB can be handled. It is also possible to pick up images by time division. According to this method, a color image can be obtained without providing a color filter in the imaging device.

Further, the driving of the light source device 11203 may be controlled so as to change the intensity of the output light every predetermined time. By controlling the drive of the imaging device of the camera head 11102 in synchronism with the timing of the change in the intensity of the light to acquire images in a time-division manner and synthesizing the images, a high dynamic A range of images can be generated.

Also, the light source device 11203 may be configured to be able 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 tissues is used to irradiate a narrower band of light than the irradiation light (i.e., white light) used during normal observation, thereby observing the mucosal surface layer. So-called Narrow Band Imaging, in which a predetermined tissue such as a blood vessel is imaged with high contrast, is performed. Alternatively, in special light observation, fluorescence observation may be performed in which an image is obtained from fluorescence generated by irradiation with excitation light. In fluorescence observation, the body tissue is irradiated with excitation light and the fluorescence from the body tissue is observed (autofluorescence observation), or a reagent such as indocyanine green (ICG) is locally injected into the body tissue and the body tissue is examined. A fluorescence image can be obtained by irradiating excitation light corresponding to the fluorescence wavelength of the reagent. The light source device 11203 can be configured to be able to supply narrowband light and/or excitation light corresponding to such special light observation.

FIG. 21 is a block diagram showing an example of functional configurations of the camera head 11102 and CCU 11201 shown in FIG.

The camera head 11102 has a lens unit 11401, an imaging section 11402, a drive section 11403, a communication section 11404, and a camera head control section 11405. The CCU 11201 has a communication section 11411 , an image processing section 11412 and a control section 11413 . The camera head 11102 and the CCU 11201 are communicably connected to each other via a transmission cable 11400 .

A lens unit 11401 is an optical system provided at a connection with the lens barrel 11101 . Observation light captured from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401 . A lens unit 11401 is configured by combining a plurality of lenses including a zoom lens and a focus lens.

The number of imaging elements constituting the imaging unit 11402 may be one (so-called single-plate type) or plural (so-called multi-plate type). When the image pickup unit 11402 is configured as a multi-plate type, for example, image signals corresponding to RGB may be generated by each image pickup element, and a color image may be obtained by synthesizing the image signals. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for respectively acquiring right-eye and left-eye image signals corresponding to 3D (dimensional) display. The 3D display enables the operator 11131 to more accurately grasp the depth of the living tissue in the surgical site. Note that when the imaging unit 11402 is configured as a multi-plate type, a plurality of systems of lens units 11401 may be provided corresponding to each imaging element.

Also, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102 . For example, the imaging unit 11402 may be provided inside the lens barrel 11101 immediately after the objective lens.

The drive unit 11403 is configured by an actuator, and moves the zoom lens and focus lens of the lens unit 11401 by a predetermined distance along the optical axis under control from the camera head control unit 11405 . Thereby, the magnification and focus of the image captured by the imaging unit 11402 can be appropriately adjusted.

The communication unit 11404 is composed of a communication device for transmitting and receiving various information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 as RAW data to the CCU 11201 via the transmission cable 11400 .

Also, the communication unit 11404 receives a control signal for controlling driving of the camera head 11102 from the CCU 11201 and supplies it to the camera head control unit 11405 . The control signal includes, for example, information to specify the frame rate of the captured image, information to specify the exposure value at the time of imaging, and/or information to specify the magnification and focus of the captured image. Contains information about conditions.

Note that the imaging conditions such as the frame rate, exposure value, magnification, and focus may be appropriately designated by the user, or may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. good. In the latter case, the endoscope 11100 is equipped with so-called AE (Auto Exposure) function, AF (Auto Focus) function and AWB (Auto White Balance) function.

The camera head control unit 11405 controls driving of the camera head 11102 based on the control signal from the CCU 11201 received via the communication unit 11404.

The communication unit 11411 is composed of a communication device for transmitting and receiving various information to and from the camera head 11102 . The communication unit 11411 receives image signals transmitted from the camera head 11102 via the transmission cable 11400 .

Also, the communication unit 11411 transmits a control signal for controlling driving of the camera head 11102 to the camera head 11102 . Image signals and control signals can be transmitted by electric communication, optical communication, or the like.

The image processing unit 11412 performs various types of image processing on the image signal, which is RAW data transmitted from the camera head 11102 .

The control unit 11413 performs various controls related to imaging of the surgical site and the like by the endoscope 11100 and display of the captured image obtained by imaging the surgical site and the like. For example, the control unit 11413 generates control signals for controlling driving of the camera head 11102 .

In addition, the control unit 11413 causes the display device 11202 to display a captured image showing the surgical site and the like based on the image signal that has undergone image processing by the image processing unit 11412 . At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition techniques. For example, the control unit 11413 detects the shape, color, and the like of the edges of objects included in the captured image, thereby detecting surgical instruments such as forceps, specific body parts, bleeding, mist during use of the energy treatment instrument 11112, and the like. can recognize. When displaying the captured image on the display device 11202, the control unit 11413 may use the recognition result to display various types of surgical assistance information superimposed on the image of the surgical site. By superimposing and presenting the surgery support information to the operator 11131, the burden on the operator 11131 can be reduced and the operator 11131 can proceed with the surgery reliably.

A transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable compatible with electrical signal communication, an optical fiber compatible with optical communication, or a composite cable of these.

Here, in the illustrated example, wired communication is performed using the transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may be performed wirelessly.

An example of an endoscopic surgery system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the imaging unit 11402 of the camera head 11102 among the configurations described above. Specifically, the solid-state imaging device 1 in FIG. 1 can be applied to the imaging unit 11402 . By applying the technology according to the present disclosure to the imaging unit 11402, a high-quality image of the operated area with improved dynamic range and SN ratio can be obtained from the imaging unit 11402, so that the operator can reliably confirm the operated area. it becomes possible to

Although the endoscopic surgery system has been described as an example here, the technology according to the present disclosure may also be applied to, for example, a microsurgery system.

Although the embodiments of the present disclosure have been described above, the technical scope of the present disclosure is not limited to the embodiments described above, and various modifications are possible without departing from the gist of the present disclosure. Moreover, you may combine the component over different embodiment and modifications suitably.

In addition, the effects described in this specification are only examples and are not limited, and other effects may also occur.

Note that the present technology can also take the following configuration.
(1)
a light-receiving pixel having a photodiode;
The photodiode is
a first conductivity type first impurity region;
a capacitance expansion region arranged laterally of the first impurity region;
a second conductivity type second impurity region arranged to surround the first impurity region and the capacitance expansion region;
has
The capacitance expanding region is a photodetector formed by alternately stacking a first-conductivity-type third impurity region and a second-conductivity-type fourth impurity region along the thickness direction of the substrate.
(2)
The light receiving pixel has a transfer transistor arranged adjacent to the photodiode,
The photodetector according to (1), wherein the first impurity region is arranged between the capacitance enlarging region and the transfer transistor.
(3)
The photodetecting element according to (2), wherein the capacitance enlarging region is arranged in a comb shape in a plan view.
(4)
The photodetecting element according to (3), wherein the capacitance enlarging region has a tapered shape in which the width gradually narrows as it approaches the transfer transistor in a plan view.
(5)
The photodetector according to any one of (2) to (4), wherein the transfer transistor is a vertical transistor having a gate electrode extending along the thickness direction of the substrate.
(6)
The photodetecting element according to (5), wherein the capacitance enlarging region is arranged close to the transfer transistor, which is a vertical transistor.
(7)
The photodetector element according to any one of (2) to (6), wherein the width of the capacity expansion region gradually widens as the distance from the transfer transistor increases.
(8)
The photodetector element according to any one of (1) to (7), wherein the capacity expansion region is wider than the first impurity region in plan view.
(9)
an optical system;
a photodetector;
with
The photodetector is
having a light-receiving pixel with a photodiode;
The photodiode is
a first conductivity type first impurity region;
a capacitance expansion region arranged laterally of the first impurity region;
a second conductivity type second impurity region arranged to surround the first impurity region and the capacitance expansion region;
has
The electronic device according to claim 1, wherein the capacitance increasing region is formed by alternately stacking a first-conductivity-type third impurity region and a second-conductivity-type fourth impurity region along a thickness direction of the substrate.
(10)
The light receiving pixel has a transfer transistor arranged adjacent to the photodiode,
The electronic device according to (9), wherein the first impurity region is arranged between the capacitance enlarging region and the transfer transistor.
(11)
The electronic device according to (10), wherein the capacitance enlarging region is arranged in a comb shape in a plan view.
(12)
The electronic device according to (11), wherein the capacity expansion region has a tapered shape in which the width gradually narrows as it approaches the transfer transistor in a plan view.
(13)
The electronic device according to any one of (10) to (12), wherein the transfer transistor is a vertical transistor having a gate electrode extending along the thickness direction of the substrate.
(14)
The electronic device according to (13), wherein the capacitance enlarging region is arranged close to the transfer transistor, which is a vertical transistor.
(15)
The electronic device according to any one of (10) to (14), wherein the width of the capacitance expansion region gradually widens as the distance from the transfer transistor increases.
(16)
The electronic device according to any one of (9) to (15), wherein the capacity expansion region is wider than the first impurity region in plan view.

1 Solid-state imaging device (an example of a photodetector)
2 Light-receiving pixel 11 Substrate 20 Photodiode 21 First impurity region 22 Second impurity region 30 Capacity expansion region 31 Third impurity region 32 Fourth impurity region 40 Transfer transistor 50 Floating diffusion 101 Imaging device 102 Optical system

Claims

a light-receiving pixel having a photodiode;
The photodiode is
a first conductivity type first impurity region;
a capacitance expansion region arranged laterally of the first impurity region;
a second conductivity type second impurity region arranged to surround the first impurity region and the capacitance expansion region;
has
The capacitance expanding region is a photodetector formed by alternately stacking a first-conductivity-type third impurity region and a second-conductivity-type fourth impurity region along the thickness direction of the substrate.
The light receiving pixel has a transfer transistor arranged adjacent to the photodiode,
2. The photodetector according to claim 1, wherein the first impurity region is arranged between the capacitance enlarging region and the transfer transistor.
3. The photodetector according to claim 2, wherein the capacitance enlarging region is arranged in a comb shape in plan view.
4. The photodetector according to claim 3, wherein the capacitance enlarging region has a tapered shape whose width gradually narrows as it approaches the transfer transistor in plan view.
3. The photodetector according to claim 2, wherein the transfer transistor is a vertical transistor having a gate electrode extending along the thickness direction of the substrate.
6. The photodetector device according to claim 5, wherein the capacitance enlarging region is arranged close to the transfer transistor, which is a vertical transistor.
3. The photodetector according to claim 2, wherein the width of the capacitance expansion region gradually widens as the distance from the transfer transistor increases.
2. The photodetector according to claim 1, wherein the capacitance enlarging region is wider than the first impurity region in plan view.
an optical system;
a photodetector;
with
The photodetector is
having a light-receiving pixel with a photodiode;
The photodiode is
a first conductivity type first impurity region;
a capacitance expansion region arranged laterally of the first impurity region;
a second conductivity type second impurity region arranged to surround the first impurity region and the capacitance expansion region;
has
The electronic device according to claim 1, wherein the capacitance increasing region is formed by alternately stacking a first-conductivity-type third impurity region and a second-conductivity-type fourth impurity region along a thickness direction of the substrate.