Light detection device and electronic equipment

Abstract

A light detection device according to an embodiment comprises: a photoelectric conversion unit that is provided on a substrate and generates electric charge corresponding to incident light by photoelectric conversion; a charge holding unit that is provided on the substrate and holds the electric charge; and a charge transfer unit that is provided on the substrate and transfers the electric charge from the photoelectric conversion unit to the charge holding unit. The charge transfer unit includes a vertical gate electrode. The vertical gate electrode includes a vertical electrode portion extending in the thickness direction of the substrate, and a lateral electrode portion extending in a direction intersecting the thickness direction. The length in plan view of the vertical electrode portion is at least twice the thickness in cross-sectional view of the lateral electrode portion.

Description

Optical Detection Device and Electronic Device

[0001] The present disclosure relates to an optical detection device and an electronic device.

[0002] In an optical detection device such as an imaging element (e.g., a CMOS image sensor), a photoelectric conversion unit in a pixel generates charges in response to incident light during an exposure period, and after the passage of the exposure period, a charge transfer unit transfers the charges from the photoelectric conversion unit to a charge holding unit. The charge transfer unit has, for example, a vertical gate electrode embedded in the surface of a semiconductor substrate (see, for example, Patent Document 1).

[0003] Japanese Unexamined Patent Application Publication No. 2021 - 193696

[0004] However, as the pixels are miniaturized, miniaturization of the vertical gate electrode is required. However, if the diameter of the vertical gate electrode is simply reduced, the charge transfer ability will decrease. Therefore, it is required to realize miniaturization of the vertical gate electrode while maintaining the charge transfer ability.

[0005] Therefore, the present disclosure provides an optical detection device and an electronic device capable of realizing miniaturization of the vertical gate electrode while maintaining the charge transfer ability.

[0006] The optical detection device according to an embodiment is provided on a substrate, and includes a photoelectric conversion unit that generates charges corresponding to incident light by photoelectric conversion, a charge holding unit that is provided on the substrate and holds the charges, and a charge transfer unit that is provided on the substrate and transfers the charges from the photoelectric conversion unit to the charge holding unit. The charge transfer unit includes a vertical gate electrode, and the vertical gate electrode includes a vertical electrode portion that extends in the thickness direction of the substrate and a horizontal electrode portion that extends in a direction intersecting the thickness direction. The length of the vertical electrode portion in plan view is 2 times or more the thickness of the horizontal electrode portion in cross-sectional view.

[0007] The electronic device according to this embodiment includes a photodetector, the photodetector being provided on a substrate and comprising: a photoelectric conversion unit that generates an electric charge corresponding to incident light by photoelectric conversion; a charge holding unit provided on the substrate and holding the electric charge; and a charge transfer unit provided on the substrate and transferring the electric charge from the photoelectric conversion unit to the charge holding unit, the charge transfer unit including a vertical gate electrode, the vertical gate electrode comprising a vertical electrode portion extending in the thickness direction of the substrate and a horizontal electrode portion extending in a direction intersecting the thickness direction, the length of the vertical electrode portion in plan view being at least twice the thickness of the horizontal electrode portion in cross-sectional view.

[0008] This is a cross-sectional view showing an example of the pixel configuration of a photodetector according to an embodiment. This is a circuit diagram showing an example of the pixel circuit configuration of a pixel according to an embodiment. This is a cross-sectional view showing an example of the configuration of a vertical gate electrode according to an embodiment. This is a plan view showing the top surface of the vertical gate electrode according to an embodiment. This is a diagram showing an example of the first manufacturing process of the vertical gate electrode according to an embodiment. This is a diagram showing an example of the second manufacturing process of the vertical gate electrode according to an embodiment. This is a diagram showing an example of the configuration of a photodetector. This is a diagram showing an example of the configuration of another photodetector. This is a diagram showing an example of the configuration of a sensor pixel and a readout circuit. This is a block diagram showing an example of the configuration of an electronic device. This is a block diagram showing an example of the schematic configuration of a vehicle control system. This is an explanatory diagram showing an example of the installation position of the external information detection unit and the imaging unit. This is a diagram showing an example of the schematic configuration of an endoscopic surgery system. This is a block diagram showing an example of the functional configuration of a camera head and a CCU.

[0009] Embodiments of this disclosure will be described in detail below with reference to the drawings. Embodiments include examples and modifications. However, the technology relating to this disclosure is not limited by the embodiments. In addition, in the following embodiments, the same reference numerals are used for essentially the same parts to omit redundant explanations.

[0010] This disclosure will be described in the following order of items: 1. Embodiments 1-1. Example of Pixel Configuration of a Photodetector 1-2. Example of Pixel Circuit Configuration 1-3. Example of Vertical Token Configuration 1-4. Example of Manufacturing Process for Vertical Token 2. Operation and Effects of the Embodiment 3. Other Embodiments 4. Application Examples 4-1. Application Example to a Photodetector 4-2. Application Example to Other Photodetectors 4-3. Application Example to Electronic Devices 4-4. Application Example to Mobile Devices 4-5. Application Example to Endoscopic Surgical Systems 5. Notes

[0011] <1. Embodiments> <1-1. Example of Pixel Configuration of Photodetector> The pixel 10 of the photodetector according to the embodiment will be described with reference to Figure 1. Figure 1 is a cross-sectional view showing an example of the configuration of the pixel 10 of the photodetector according to the embodiment. The pixel 10 is, for example, an example of a back-illuminated type photodetector.

[0012] As shown in Figure 1, the pixel 10 according to the embodiment comprises a substrate 20, a separation portion 30, a plurality of insulating layers 40, 50, a wiring layer 60, a color filter 70, and an on-chip lens 80.

[0013] The substrate 20 is a semiconductor substrate on which elements and other components are arranged. This substrate 20 is made of, for example, silicon (Si). The substrate 20 is provided with a photoelectric conversion unit 21, a charge holding unit 22, and a charge transfer unit 23. The photoelectric conversion unit 21 is located in a well region formed in the substrate 20.

[0014] In the example shown in Figure 1, for convenience, it is assumed that the substrate 20 constitutes a p-type well region. By arranging n-type and p-type semiconductor regions in this p-type well region, for example, a diffusion layer for a device can be formed.

[0015] The photoelectric conversion unit 21 is composed of an n-type semiconductor region 21a. Specifically, for example, a pn junction is formed at the interface between the semiconductor region 21a and the surrounding p-type well region, and the photodiode composed of this pn junction corresponds to the photoelectric conversion unit 21.

[0016] The charge-holding portion 22 is composed of a semiconductor region 22a configured with a relatively high concentration of n-type impurities. This semiconductor region 22a constitutes, for example, a floating diffusion layer.

[0017] The charge transfer unit 23 is composed of a semiconductor region 21a, a semiconductor region 22a, and a vertical gate (VG) 90. The n-type semiconductor regions 21a and 22a correspond to the source region and drain region of the charge transfer unit 23.

[0018] The vertical gate electrode 90 is composed of a vertical electrode portion 91 and a horizontal electrode portion 92. The vertical electrode portion 91 is located inside the substrate 20 and is formed in a shape that extends in the vertical direction (for example, in the Z-axis direction). The horizontal electrode portion 92 is located on the surface of the substrate 20 and is formed in a shape that extends in the horizontal direction (for example, in a direction perpendicular to the Z-axis direction). For example, the upper part (top surface) of the vertical electrode portion 91 and the lower part (bottom surface) of the horizontal electrode portion 92 are in contact, and the vertical electrode portion 91 and the horizontal electrode portion 92 are integrated. The vertical direction corresponds to the thickness direction of the substrate 20, and the horizontal direction corresponds to the planar direction of the substrate 20.

[0019] When an ON voltage is applied to such a vertical gate electrode 90, a channel is formed in the semiconductor region on the surface of the vertical gate electrode 90, and the semiconductor region 21a and the semiconductor region 22a become conductive. That is, the photoelectric conversion unit 21 and the charge holding unit 22 become conductive, and the charge from the photoelectric conversion unit 21 is transferred to the charge holding unit 22. In this way, the charge transfer unit 23 transfers charge in the thickness direction of the substrate 20.

[0020] The insulating layer 40 is provided on the surface of the substrate 20. The insulating layer 50 is provided on the back surface of the substrate 20. These insulating layers 40 and 50 are made of, for example, silicon oxide (SiO ２ It is made of ) or silicon nitride (SiN). A gate insulating film (not shown in Figure 1) is placed between the vertical gate electrode 90 and the substrate 20.

[0021] The separation portion 30 is positioned at the boundary of the pixel 10 to separate the pixel 10. The separation portion 30 is formed in a shape that penetrates from the front side to the back side of the substrate 20, for example. For example, the separation portion 30 is formed in a groove formed in the substrate 20 with SiO ２ It is constructed by embedding insulating materials such as these.

[0022] A semiconductor region 21b and a semiconductor region 21c are positioned between the separation section 30 and the semiconductor region 21a. Semiconductor region 21b is a semiconductor region conformally configured with a relatively high concentration of p-type impurities and is located on the separation section 30 side. This semiconductor region 21b is a semiconductor region that pins the interface states of the substrate 20. Semiconductor region 21c is a semiconductor region conformally configured with a relatively high concentration of n-type impurities and is located on the semiconductor region 21a side. Together with semiconductor region 21a, this semiconductor region 21c constitutes a photoelectric conversion section 21 that stores the photoelectrically converted charge.

[0023] The wiring layer 60 is an area on the surface side of the substrate 20 where wiring is arranged to transmit signals from elements, etc. The wiring layer 60 has an insulating layer 61, wiring 62, and connection parts 63. The insulating layer 61 insulates electrodes, wiring 62, etc., which are arranged on the surface side of the substrate 20. This insulating layer 61 is made of, for example, SiO ２ The circuit is composed of the above. The wiring 62 transmits signals to elements formed on the substrate 20. The connection part 63 connects elements, electrodes, wiring 62, etc. formed on the substrate 20. In the example in Figure 1, the connection part 63 is a contact layer that connects the wiring 62 and the vertical gate electrode 90. The wiring 62 and connection part 63 are made of, for example, tungsten (W) or copper (Cu).

[0024] The color filter 70 is an optical filter that transmits light of a predetermined wavelength from the incident light. For example, a color filter that transmits red light, green light, and blue light can be used as the color filter 70.

[0025] The on-chip lens 80 is a lens that focuses incident light. For example, the on-chip lens 80 is configured in a hemispherical shape. This on-chip lens 80 focuses the incident light onto the photoelectric conversion unit 21.

[0026] <1-2. Example of Pixel Circuit Configuration> An example of the pixel circuit configuration of the pixel 10 according to the embodiment will be described with reference to Figure 2. Figure 2 is a circuit diagram showing an example of the pixel circuit configuration of the pixel 10 according to the embodiment.

[0027] As shown in Figure 2, the pixel 10 includes, in addition to the aforementioned photoelectric conversion unit 21, charge holding unit 22, and charge transfer unit 23, a reset transistor 24, an amplification transistor 25, and a selection transistor 26. Note that the pixel 10 is not limited to the example in Figure 2, and may include other elements, for example.

[0028] For example, a floating diffusion is used as the charge holding unit 22. For example, a transfer transistor is used as the charge transfer unit 23. For example, a CMOS (Complementary Metal Oxide Semiconductor) transistor is used as this transfer transistor. Similarly, for example, CMOS transistors are used as the reset transistor 24, the amplification transistor 25, and the selection transistor 26.

[0029] The photoelectric conversion unit 21 performs photoelectric conversion on incident light, generating an electric charge corresponding to the amount of light received. One end of the photoelectric conversion unit 21 is electrically connected to one of the source / drain of a transfer transistor, which is an example of a charge transfer unit 23. The other end of the photoelectric conversion unit 21 is electrically connected to a reference potential line (e.g., ground). The other end of the source / drain of the transfer transistor is electrically connected to a charge holding unit 22. When the transfer transistor is turned on, it transfers the charge generated by the photoelectric conversion unit 21 to the charge holding unit 22. The charge holding unit 22 stores the transferred charge. The charge holding unit 22 temporarily holds the charge output from the photoelectric conversion unit 21 via the transfer transistor.

[0030] One source / drain of the reset transistor 24 is electrically connected to the charge holding unit 22, and the other source / drain of the reset transistor 24 is electrically connected to the power line VDD. The reset transistor 24 resets the potential of the charge holding unit 22 to a predetermined potential. Specifically, when the reset transistor 24 is turned on, it sets the potential of the charge holding unit 22 to the potential of the power line VDD, and resets the charge accumulated in the charge holding unit 22.

[0031] The gate of the amplification transistor 25 is electrically connected to the charge holding unit 22. The amplification transistor 25 generates a voltage signal (pixel signal) corresponding to the amount of charge stored in the charge holding unit 22. One source / drain of the amplification transistor 25 is connected to one source / drain of the selection transistor 26, and the other source / drain of the amplification transistor 25 is electrically connected to the power line VDD.

[0032] The source / drain of the selection transistor 26 is electrically connected to the vertical signal line 11. The selection transistor 26 controls the output timing of the pixel signal. Specifically, when the selection transistor 26 is turned on, the amplification transistor 25 outputs the pixel signal to the vertical signal line 11.

[0033] <1-3. Example of Vertical Guard Gate Configuration> An example of the configuration of the vertical guard gate 90 according to the embodiment will be described with reference to Figures 3 and 4. Figure 3 is a cross-sectional view showing an example of the configuration of the vertical guard gate 90 according to the embodiment. Figure 4 is a plan view showing the top surface of the vertical guard gate 90 according to the embodiment.

[0034] As shown in Figures 3 and 4, the vertical gate electrode 90 has a vertical electrode portion 91 and a horizontal electrode portion (flat portion) 92. This vertical gate electrode 90 guides charge from the photoelectric conversion portion 21 provided on the back side of the substrate 20 to the charge holding portion 22. The vertical gate electrode 90 is sometimes called, for example, an embedded gate electrode.

[0035] The vertical electrode portion 91 extends in the thickness direction of the substrate 20 (for example, in the Z-axis direction). The horizontal electrode portion 92 extends in a direction intersecting the thickness direction (for example, in a direction perpendicular to the thickness direction). The vertical gate electrode 90, including these vertical electrode portions 91 and horizontal electrode portions 92, can guide the charge accumulated in the photoelectric conversion portion 21 to the charge holding portion 22 and efficiently transfer it to the charge holding portion 22.

[0036] The horizontal electrode portion 92 includes a groove portion 92a having depth in the thickness direction of the substrate 20. This groove portion 92a is formed on the upper surface of the horizontal electrode portion 92 (the surface of the horizontal electrode portion 92 opposite to the vertical electrode portion 91 side). The upper surface of the horizontal electrode portion 92 is formed in a shape that extends in a predetermined direction, for example, an elliptical shape extending in the Y-axis direction (see Figure 4). In a plan view, the groove portion 92a extends in the same direction as the longitudinal direction (extension direction) of the horizontal electrode portion 92, for example, in the Y-axis direction. The groove portion 92a is sometimes called a seam.

[0037] The length X1 in the short direction (X-axis direction) of the vertical electrode portion 91 in a plan view is at least twice the thickness (height) Z1 of the horizontal electrode portion 92 in a cross-sectional view (X1 ≥ 2 × Z1). Also, the depth (height) Z2 of the groove portion 92a in a cross-sectional view is less than the thickness Z1 of the horizontal electrode portion 92 in a cross-sectional view (Z2 < Z1). If the length X1 in the short direction of the vertical electrode portion 91 in a plan view becomes shorter than twice the thickness Z1 of the horizontal electrode portion 92 in a cross-sectional view, it becomes difficult to maintain the charge transfer capability of the charge transfer portion 23. Note that the length X1 in the short direction of the vertical electrode portion 91 in a plan view corresponds to the length in the short direction of the opening (trench opening) of the vertical gate electrode 90 in a plan view.

[0038] The vertical gate electrode 90 is composed of, for example, an embedded member 95 embedded in the substrate 20. Specifically, the vertical electrode portion 91 and the horizontal electrode portion 92 are composed of the embedded member 95. The embedded member 95 is embedded, for example, in a trench 20A that extends in the thickness direction from the upper surface of the substrate 20. This embedded member 95 is formed of, for example, polysilicon, tungsten, tantalum nitride, ruthenium oxide, titanium nitride, tungsten nitride, or iridium.

[0039] An insulating film (gate insulating film) 20a is provided between the vertical gate electrode 90 and the substrate 20. The insulating film 20a is provided, for example, on the surface of the substrate 20 including the trench 20A, and covers the side surface and the bottom surface of the vertical electrode portion 91. This insulating film 20a is formed of, for example, any one of silicon oxide, silicon oxynitride, hafnium dioxide, zirconium dioxide, titanium dioxide, and aluminum oxide.

[0040] According to the vertical gate electrode 90 having such a configuration, the length X1 in the short side direction in the plan view of the vertical electrode portion 91 is not less than twice the thickness Z1 in the cross-sectional view of the horizontal electrode portion 92 (X1≧2×Z1). Thereby, in the vertical gate electrode 90, it is possible to thin the horizontal electrode portion 92 while maintaining an appropriate size of the vertical electrode portion 91, so that miniaturization of the vertical gate electrode 90 can be achieved while maintaining the charge transfer ability.

[0041] Further, the depth (height) Z2 in the cross-sectional view of the groove portion 92a is smaller than the thickness Z1 in the cross-sectional view of the horizontal electrode portion 92 (Z2<Z1). Thereby, the generation of the groove portion 92a (for example, the depth of the groove portion 92a) is suppressed. This groove portion 92a causes, for example, dust generation due to unnecessary film formation in a subsequent process, and contact failure. Therefore, by suppressing the generation of the groove portion 92a, the risk of dust generation can be avoided, and the occurrence of connection failure between the vertical gate electrode 90 and the connection portion 63 can be suppressed.

[0042] Note that the upper surface of the horizontal electrode portion 92 is formed in an elliptical shape extending in a predetermined direction such as the Y-axis direction, but is not limited thereto. An ellipse is a shape including the length (major axis) in the longitudinal direction (extension direction) and the length (minor axis) in the short side direction (direction orthogonal to the extension direction). The upper surface of the horizontal electrode portion 92 may be formed in, for example, a circular shape or a polygonal shape (for example, a square shape, an octagonal shape, etc.), or may be formed in a polygonal shape extending in a predetermined direction (for example, a rectangular shape extending in a predetermined direction, an octagonal shape extending in a predetermined direction, etc.). A polygonal shape extending in a predetermined direction is also a shape including, for example, the length in the longitudinal direction and the length in the short side direction.

[0043] Here, the vertical electrode portion 91 may be configured to have a refractive index lower than that of Si, which is a member constituting the substrate 20, for example. In this case, it becomes possible to extend the optical path length of the light incident from the back surface side of the substrate 20, and the photoelectric conversion efficiency (for example, quantum efficiency) can be improved. Also, the horizontal electrode portion 92 may be configured to have a refractive index lower than that of Si, which constitutes the substrate 20, similarly to the vertical electrode portion 91.

[0044] Also, the vertical electrode portion 91 may be formed of, for example, a transparent conductive member. This transparent conductive member includes, for example, ITO (Indium Tin Oxide), In ２ O ３ , ZnO (Zinc Oxide), IZO (Indium Zinc Oxide), and IGZO (In-Ga-Zn-O). Also, the vertical electrode portion 91 may be formed of, for example, a metal. This metal includes, for example, aluminum, gold, silver, and Cu.

[0045] Also, the horizontal electrode portion 92 may be formed of a member that absorbs or reflects incident light. In this case, it becomes possible to absorb or reflect the light incident through the vertical electrode portion 91 by the horizontal electrode portion 92. Thereby, leakage of the incident light to the wiring layer 60 can be suppressed.

[0046] <1-4. Example of manufacturing process of vertical gate electrode> An example of the manufacturing process of the vertical gate electrode 90 according to the embodiment will be described with reference to FIGS. 5 and 6. FIG. 5 is a diagram showing a first manufacturing process example of the vertical gate electrode 90 according to the embodiment. FIG. 6 is a diagram showing a second manufacturing process example of the vertical gate electrode 90 according to the embodiment.

[0047] (First manufacturing process) As shown in FIG. 5, a trench 20A is formed on the surface of the substrate 20, and an insulating film 20a is laminated on the surface of the substrate 20 including the trench 20A. Next, an embedding member 95 is laminated on the insulating film 20a on the substrate 20. For example, an embedding member 95 such as polysilicon is embedded in the trench 20A. At this time, a groove portion (seam) 95a is formed on the upper surface of the embedding member 95. This groove portion 95a corresponds to the groove portion 92a described above.

[0048] Next, the embedded member 95 on the substrate 20 is thinned using etching techniques such as dry etching or CMP (Chemical Mechanical Polishing). This forms the vertical gate electrode 90. In etching, for example, by adjusting the etching amount for each wafer, it is possible to reduce variations in film thickness from wafer to wafer, thereby achieving stable characteristics and improved yield. Subsequently, insulating layers 40, 61, etc. are laminated onto the vertical gate electrode 90 on the substrate 20 to form a connection portion 63 that will serve as the gate contact. The connection portion 63 is formed to contact the vertical gate electrode 90, i.e., a predetermined region including the groove portion 92a, from a position opposite the groove portion 92a of the vertical gate electrode 90.

[0049] (Second Manufacturing Process) As shown in Figure 6, similar to the first manufacturing process, trenches 20A are processed on the surface of the substrate 20, and an insulating film 20a is laminated on the surface of the substrate 20 including the trenches 20A. Next, an embedded member 95 is laminated on the insulating film 20a on the substrate 20. For example, an embedded member 95 such as polysilicon is embedded in the trenches 20A. At this time, a groove (seam) 95a is formed on the upper surface of the embedded member 95. This groove 95a corresponds to the groove 92a mentioned above.

[0050] Next, an organic film 96 is laminated onto the embedded member 95 on the substrate 20. If the surface of the embedded member 95 on the substrate 20 is rough, the flatness in subsequent processes will deteriorate. For this reason, the organic film 96 is used to improve flatness. Next, the organic film 96 and the embedded member 95 on the substrate 20 are thinned using etching techniques such as EB or CMP. This forms a vertical gate electrode 90. During EB, for example, the flatness of the surface of the embedded member 95 can be improved by adjusting the selectivity ratio of the EB. After that, insulating layers 40, 61, etc. are laminated onto the vertical gate electrode 90 on the substrate 20 to form a connection portion 63 that will become a gate contact.

[0051] <2. Operation and Effects of the Embodiment> As described above, the photodetector according to the embodiment includes a photoelectric conversion unit 21 provided on a substrate 20 (for example, a semiconductor substrate) that generates an electric charge corresponding to incident light by photoelectric conversion, a charge holding unit 22 provided on the substrate 20 that holds the charge, and a charge transfer unit 23 provided on the substrate 20 that transfers the charge from the photoelectric conversion unit 21 to the charge holding unit 22. The charge transfer unit 23 includes a vertical gate electrode 90, and the vertical gate electrode 90 includes a vertical electrode portion 91 extending in the thickness direction of the substrate 20 (for example, the Z-axis direction) and a horizontal electrode portion 92 extending in a direction intersecting the thickness direction. The length X1 of the vertical electrode portion 91 in a plan view is at least twice the thickness Z1 of the horizontal electrode portion 92 in a cross-sectional view (see Figures 1 to 4). This makes it possible to thin the horizontal electrode portion 92 in the vertical gate electrode 90 while maintaining an appropriate size for the vertical electrode portion 91, thereby enabling miniaturization of the vertical gate electrode 90 while maintaining charge transfer capability.

[0052] Furthermore, the shape of the vertical electrode portion 91 in plan view is a shape that extends in a predetermined direction (for example, an elliptical shape extending in the Y-axis direction), and the length X1 of the vertical electrode portion 91 in plan view may be the length in the shorter direction (for example, the X-axis direction) in plan view of the vertical electrode portion 91 (see Figures 3 and 4). This ensures the maintenance of charge transfer capability and the miniaturization of the vertical gate electrode 90.

[0053] Furthermore, the shape of the vertical electrode portion 91 in plan view may be elliptical (see Figures 3 and 4). Even with such a configuration, it is possible to maintain charge transfer capability and miniaturize the vertical gate electrode 90.

[0054] Furthermore, the lateral electrode portion 92 may include a groove portion 92a having depth in the thickness direction of the substrate 20 (for example, in the Z-axis direction) (see Figures 3 and 4). Even with such a configuration, it is possible to maintain charge transfer capability and miniaturize the vertical gate electrode 90.

[0055] Furthermore, the length X1 of the vertical electrode portion 91 in plan view may be the length in a direction perpendicular to the extension direction of the groove portion 92a (for example, the Y-axis direction) (see Figures 3 and 4). This makes it possible to suppress the generation of the groove portion 92a (for example, the depth of the groove portion 92a).

[0056] Furthermore, the depth Z2 of the groove 92a in a cross-sectional view may be smaller than the thickness Z1 of the horizontal electrode portion 92 in a cross-sectional view (see Figures 3 and 4). This ensures that the occurrence of the groove 92a (for example, the depth of the groove 92a) is suppressed.

[0057] Furthermore, the photodetector may also include a connection portion 63 provided on the substrate 20, and the connection portion 63 may be formed to contact the vertical gate electrode 90 from a position opposite to the groove portion 92a (see Figures 1, 5, and 6). Even with such a configuration, it is possible to maintain charge transfer capability and miniaturize the vertical gate electrode 90.

[0058] Furthermore, the vertical gate electrode 90 may be composed of an embedded member 95 embedded in the substrate 20 (see Figures 3 to 6). This makes it easy to form the vertical gate electrode 90.

[0059] Furthermore, the embedded member 95 may be formed from any of the following materials: polysilicon, tungsten, tantalum nitride, ruthenium oxide, titanium nitride, tungsten nitride, or iridium (see Figures 3 to 6). This improves the design flexibility of the vertical gate electrode 90.

[0060] Furthermore, the photodetector also includes an insulating film 20a provided between the vertical gate electrode 90 and the substrate 20, and the insulating film 20a may be formed from any of silicon oxide, silicon oxynitride, hafnium dioxide, zirconium dioxide, titanium dioxide, or aluminum oxide (see Figures 3 to 6). This improves the design flexibility of the insulating film 20a.

[0061] <3. Other Embodiments> The configurations and processes described in the above-described embodiments (including examples and modifications) may be implemented in various other forms besides those described above. For example, the configurations and processes may be in various forms, not limited to the examples described above. Also, for example, the configurations, processing procedures, specific names, and information including various data and parameters shown in the above document and drawings may be changed at will unless otherwise specified.

[0062] Furthermore, the configurations and processes described in the above-mentioned embodiments (including examples and modifications) do not necessarily have to be physically configured as shown in the figures. In other words, the specific forms of distribution and integration of each configuration and process are not limited to those shown in the figures, and all or part of them may be functionally or physically distributed or integrated in any unit depending on various loads and usage conditions.

[0063] Furthermore, the various configurations and processes described in the above-mentioned embodiments (including examples and modifications) may be combined as appropriate. For example, at least a part of one embodiment may be combined with at least a part of another embodiment as appropriate. Also, the effects described in the embodiments are merely illustrative and not limiting, and other effects may also occur.

[0064] <4. Application Examples> <4-1. Application Examples to Photodetection Devices> The technology relating to this disclosure (this technology) can be applied to various products. For example, the technology relating to this disclosure may be applied to a photodetection device 101 such as a CMOS solid-state imaging device.

[0065] Figure 7 shows a schematic configuration of an example of a photodetector 101, such as a CMOS solid-state imaging device. As shown in Figure 7, the photodetector 101 in this example is configured to have a pixel section (so-called imaging region) 103 in which pixels 102 containing multiple photoelectric conversion elements are regularly arranged in two dimensions on a substrate 111 such as a semiconductor substrate, for example, a silicon substrate, and a peripheral circuit section. The aforementioned pixel 10 is used as each pixel 102. Each pixel 102 consists of, for example, a photoelectric conversion element (PD) and multiple pixel transistors (so-called MOS transistors). The multiple pixel transistors can be composed of, for example, three transistors: a transfer transistor, a reset transistor, and an amplification transistor. Alternatively, a selection transistor can be added to make a total of four transistors. The equivalent circuit of the unit pixel is the same as usual, so a detailed explanation is omitted. The pixel 102 can also be a pixel-sharing structure. This pixel-sharing structure consists of multiple photodiodes, multiple transfer transistors, one shared floating diffusion, and one other shared pixel transistor.

[0066] The peripheral circuit section is composed of a vertical drive circuit 104, a column signal processing circuit 105, a horizontal drive circuit 106, an output circuit 107, a control circuit 108, and the like.

[0067] The control circuit 108 receives an input clock and data that commands the operating mode, and outputs data such as internal information of the light detection device 101. In other words, the control circuit 108 generates clock signals and control signals that serve as the reference for the operation of the vertical drive circuit 104, column signal processing circuit 105, and horizontal drive circuit 106, etc., based on the vertical synchronization signal, horizontal synchronization signal, and master clock. The control circuit 108 then inputs these signals to the vertical drive circuit 104, column signal processing circuit 105, and horizontal drive circuit 106, etc.

[0068] The vertical drive circuit 104 is configured, for example, by a shift register, selects a pixel drive wiring, supplies pulses to the selected pixel drive wiring to drive the pixels, and drives the pixels row by row. That is, the vertical drive circuit 104 sequentially selects and scans each pixel 102 of the pixel unit 103 vertically row by row, and supplies a pixel signal based on the signal charge generated in accordance with the amount of light received in the photoelectric conversion element, for example, the PD, of each pixel 102 via the vertical signal line 109 to the column signal processing circuit 105.

[0069] The column signal processing circuit 105 is arranged, for example, for each column of pixels 102, and performs signal processing such as noise reduction on the signals output from one row of pixels 102 for each pixel column. In other words, the column signal processing circuit 105 performs signal processing such as CDS to remove fixed pattern noise specific to pixels 102, signal amplification, and AD conversion. A horizontal selection switch (not shown) is provided at the output stage of the column signal processing circuit 105, connected to the horizontal signal line 110.

[0070] The horizontal drive circuit 106 is configured, for example, by a shift register, and sequentially outputs horizontal scanning pulses to select each of the column signal processing circuits 105 in order, causing each of the column signal processing circuits 105 to output a pixel signal to the horizontal signal line 110.

[0071] The output circuit 107 processes the signals sequentially supplied from each of the column signal processing circuits 105 through the horizontal signal line 110 and outputs them. For example, it may only perform buffering, or it may perform black level adjustment, column variation correction, and various digital signal processing. The input / output terminal 112 is used for exchanging signals with the outside.

[0072] <4-2. Examples of application to other photodetectors> The technology described herein (this technology) can be applied to various products. For example, the technology described herein may be applied to a photodetector 201 such as an image sensor.

[0073] Figure 8 shows an example of the schematic configuration of the photodetector 201 according to this disclosure. The photodetector 201 comprises three substrates (first substrate 210, second substrate 220, and third substrate 230). The photodetector 201 has a three-dimensional structure formed by bonding the three substrates (first substrate 210, second substrate 220, and third substrate 230). The first substrate 210, second substrate 220, and third substrate 230 are stacked in this order.

[0074] The first substrate 210 has a semiconductor substrate 211 with a plurality of sensor pixels 212 that perform photoelectric conversion. For example, the aforementioned pixel 10 is used as each sensor pixel 212. The plurality of sensor pixels 212 are arranged in a matrix within the pixel region 213 of the first substrate 210. The second substrate 220 has a semiconductor substrate 221 with one readout circuit 222 for every four sensor pixels 212 that outputs a pixel signal based on the charge output from the sensor pixels 212. The second substrate 220 has a plurality of pixel drive lines 223 extending in the row direction and a plurality of vertical signal lines 224 extending in the column direction. The third substrate 230 has a semiconductor substrate 231 with a logic circuit 232 that processes pixel signals. The logic circuit 232 includes, for example, a vertical drive circuit 233, a column signal processing circuit 234, a horizontal drive circuit 235, and a system control circuit 236. The logic circuit 232 (specifically the horizontal drive circuit 235) outputs the output voltage Vout for each sensor pixel 212 to the outside. In the logic circuit 232, for example, CoSi is used on the surface of the impurity diffusion region that is in contact with the source electrode and the drain electrode. ２ A low-resistance region may be formed from silicides, such as NiSi, that are formed using a salicide (Self-Aligned Silicide) process.

[0075] The vertical drive circuit 233, for example, sequentially selects a plurality of sensor pixels 212 row by row. The column signal processing circuit 234, for example, applies correlated double sampling (CDS) processing to the pixel signals output from each sensor pixel 212 in the row selected by the vertical drive circuit 233. The column signal processing circuit 234, for example, extracts the signal level of the pixel signals by applying CDS processing and holds pixel data corresponding to the amount of light received by each sensor pixel 212. The horizontal drive circuit 235, for example, sequentially outputs the pixel data held by the column signal processing circuit 234 to the outside. The system control circuit 236, for example, controls the driving of each block in the logic circuit 232 (vertical drive circuit 233, column signal processing circuit 234, and horizontal drive circuit 235).

[0076] Figure 9 shows an example of a sensor pixel 212 and a readout circuit 222. Below, we will describe the case where four sensor pixels 212 share one readout circuit 222, as shown in Figure 9. Here, "sharing" means that the outputs of the four sensor pixels 212 are input to a common readout circuit 222.

[0077] Each sensor pixel 212 has components that are common to all of them. In Figure 9, identification numbers (1, 2, 3, 4) are added to the end of the code of each sensor pixel 212 component to distinguish them from one another. Hereafter, when it is necessary to distinguish the components of each sensor pixel 212 from one another, an identification number will be added to the end of the code of each sensor pixel 212 component; however, when it is not necessary to distinguish the components of each sensor pixel 212 from one another, the identification number at the end of the code of each sensor pixel 212 component will be omitted.

[0078] Each sensor pixel 212 includes, for example, a photodiode PD, a transfer transistor TR electrically connected to the photodiode PD, and a floating diffusion FD that temporarily holds the charge output from the photodiode PD via the transfer transistor TR. The photodiode PD corresponds to one specific example of the "photoelectric conversion element" of this disclosure. The photodiode PD performs photoelectric conversion to generate a charge corresponding to the amount of light received. The cathode of the photodiode PD is electrically connected to the source of the transfer transistor TR, and the anode of the photodiode PD is electrically connected to a reference potential line (e.g., ground GND). The drain of the transfer transistor TR is electrically connected to the floating diffusion FD, and the gate of the transfer transistor TR is electrically connected to the pixel drive line 223 (see Figure 8). The transfer transistor TR is, for example, a CMOS transistor.

[0079] The floating diffusion FDs of each sensor pixel 212 sharing a single readout circuit 222 are electrically connected to each other and are also electrically connected to the input terminal of the common readout circuit 222. The readout circuit 222 includes, for example, a reset transistor RST, a selection transistor SEL, and an amplification transistor AMP. The selection transistor SEL may be omitted if necessary. The source of the reset transistor RST (the input terminal of the readout circuit 222) is electrically connected to the floating diffusion FD, and the drain of the reset transistor RST is electrically connected to the power line VDD and the drain of the amplification transistor AMP. The gate of the reset transistor RST is electrically connected to the pixel drive line 223 (see Figure 8). The source of the amplification transistor AMP is electrically connected to the drain of the selection transistor SEL, and the gate of the amplification transistor AMP is electrically connected to the source of the reset transistor RST. The source of the selection transistor SEL (the output terminal of the readout circuit 222) is electrically connected to the vertical signal line 224, and the gate of the selection transistor SEL is electrically connected to the pixel drive line 223 (see Figure 8).

[0080] When the transfer transistor TR is turned ON, it transfers the charge from the photodiode PD to the floating diffusion FD. The reset transistor RST resets the potential of the floating diffusion FD to a predetermined potential. When the reset transistor RST is turned ON, it resets the potential of the floating diffusion FD to the potential of the power line VDD. The selection transistor SEL controls the output timing of the pixel signal from the readout circuit 222. The amplification transistor AMP generates a signal with a voltage corresponding to the level of charge held in the floating diffusion FD as the pixel signal. The amplification transistor AMP constitutes a source follower type amplifier and outputs a pixel signal with a voltage corresponding to the level of charge generated in the photodiode PD. When the selection transistor SEL is turned ON, the amplification transistor AMP amplifies the potential of the floating diffusion FD and outputs a voltage corresponding to that potential to the column signal processing circuit 234 via the vertical signal line 224. The reset transistor RST, the amplification transistor AMP, and the selection transistor SEL are, for example, CMOS transistors.

[0081] Furthermore, the pixel 10 may be applied to other photodetectors besides the aforementioned photodetectors 101 and 201. Also, the vertical gate electrode 90 of the pixel 10 may be applied to various semiconductor devices. For example, the photodetectors 101 and 201 can be considered types of semiconductor devices.

[0082] <4-3. Examples of applications to electronic devices> Furthermore, the light detection devices described above (for example, light detection device 101, light detection device 201, etc.) can be applied to various electronic devices such as imaging systems such as digital still cameras and digital video cameras, mobile phones equipped with imaging functions, or other devices equipped with imaging functions.

[0083] Figure 10 is a block diagram showing an example configuration of the electronic device 301.

[0084] As shown in Figure 10, the electronic device 301 includes an optical system 302, a light detection device 303, and a DSP (Digital Signal Processor) 304. The DSP 304, display device 305, operating system 306, memory 308, recording device 309, and power supply system 310 are connected via a bus 307, and it is capable of capturing still and moving images.

[0085] The optical system 302 is composed of one or more lenses and guides the image light (incident light) from the subject to the light detection device 303, where it forms an image on the light-receiving surface (sensor part) of the light detection device 303.

[0086] As the photodetector 303, any of the photodetectors described in the above-described configuration examples (for example, photodetector 101, photodetector 201, etc.) is used. Electrons are accumulated in the photodetector 303 for a certain period of time in accordance with the image formed on the light-receiving surface via the optical system 302. Then, a signal corresponding to the electrons accumulated in the photodetector 303 is supplied to the DSP 304.

[0087] The DSP 304 performs various signal processing on the signal from the light detection device 303 to acquire an image, and temporarily stores the image data in the memory 308. The image data stored in the memory 308 is recorded in the recording device 309 or supplied to the display device 305 to display the image. The operation system 306 accepts various operations from the user and supplies operation signals to each block of the electronic equipment 301, and the power supply system 310 supplies the power necessary to drive each block of the electronic equipment 301.

[0088] <4-4. Examples of Application to Mobile Devices> The technology disclosed herein (the technology) can be applied to various products. For example, the technology disclosed herein may be implemented as a device mounted on any type of mobile device such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, and robots.

[0089] Figure 11 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 described herein may be applied.

[0090] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 11, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0091] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0092] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0093] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0094] The imaging unit 12031 is a light sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0095] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that captures images of the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0096] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0097] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0098] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0099] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 11, the output devices include an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

[0100] Figure 12 shows an example of the installation position of the imaging unit 12031.

[0101] In Figure 12, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0102] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0103] Figure 12 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0104] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0105] For example, the microcomputer 12051, based on distance information obtained from the imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to the vehicle 12100). In particular, it can extract the closest object on the vehicle 12100's path that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained in front of the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, etc., that drives autonomously without driver operation, can be performed.

[0106] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid collisions by outputting a warning to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0107] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio-image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio-image output unit 12052 may also control the display unit 12062 to display an icon indicating a pedestrian at a desired position.

[0108] The above describes an example of a vehicle control system to which the technology of this disclosure may be applied. The technology of this disclosure can be applied to the imaging unit 12031, for example, among the configurations described above. Specifically, for example, the light detection device 101 and the light detection device 201, each including the aforementioned pixels 10, can be applied to the imaging unit 12031. By applying the technology of this disclosure to the imaging unit 12031, it becomes possible to obtain effects similar to those of the embodiments described above.

[0109] <4-5. Examples of Application to Endoscopic Surgical Systems> The technology disclosed herein (this technology) can be applied to various products. For example, the technology disclosed herein may be applied to an endoscopic surgical system.

[0110] Figure 13 is a diagram showing an example of a schematic configuration of an endoscopic surgical system to which the technology described herein (the technology) may be applied.

[0111] Figure 13 illustrates a surgeon (physician) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgical system 11000. As shown in the figure, the endoscopic surgical system 11000 consists of an endoscope 11100, other surgical instruments 11110 such as an insufflation tube 11111 and an energy treatment device 11112, a support arm device 11120 for supporting the endoscope 11100, and a cart 11200 equipped with various devices for endoscopic surgery.

[0112] The endoscope 11100 consists of a barrel 11101, the tip of which is inserted into the body cavity of the patient 11132 for a predetermined length, and a camera head 11102 connected to the base end of the barrel 11101. In the illustrated example, the endoscope 11100 is shown as a so-called rigid endoscope having a rigid barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible endoscope having a flexible barrel.

[0113] An opening into which an objective lens is fitted is provided at the tip of the microscope tube 11101. A light source device 11203 is connected to the endoscope 11100, and the light generated by the light source device 11203 is guided to the tip of the microscope tube by a light guide extending inside the microscope tube 11101, and is irradiated through the objective lens towards the object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a straight-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0114] The camera head 11102 contains an optical system and an image sensor. Reflected light from the object being observed (observation light) is focused onto the image sensor by the optical system. The image sensor 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. This image signal is transmitted as RAW data to the camera control unit (CCU) 11201.

[0115] The CCU 11201 is composed of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and other components, and comprehensively controls the operation of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102 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.

[0116] The display device 11202 displays an image based on an image signal that has been processed by the CCU 11201, under control from the CCU 11201.

[0117] The light source device 11203 is composed of a light source such as an LED (light-emitting diode) and supplies illumination light to the endoscope 11100 when photographing the surgical area, etc.

[0118] The input device 11204 is an input interface for the endoscopic surgical system 11000. The user can input various types of information and instructions to the endoscopic surgical system 11000 via the input device 11204. For example, the user can input instructions to change the imaging conditions (type of light, magnification, focal length, etc.) of the endoscope 11100.

[0119] The treatment instrument control device 11205 controls the drive of the energy treatment instrument 11112 for purposes such as tissue cauterization, incision, or blood vessel sealing. The insufflation device 11206 injects gas into the body cavity of the patient 11132 via the insufflation tube 11111 to inflate the body cavity for the purpose of securing a field of view by the endoscope 11100 and securing the operator's workspace. The recorder 11207 is a device capable of recording various information related to the surgery. The printer 11208 is a device capable of printing various information related to the surgery in various formats such as text, images, or graphs.

[0120] The light source device 11203 that supplies illumination light to the endoscope 11100 when photographing the surgical area can be configured as a white light source consisting of, for example, an LED, a laser light source, or a combination thereof. When the white light source is configured as 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 11203. 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 11102 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.

[0121] Furthermore, the light source device 11203 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 11102 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.

[0122] Furthermore, the light source device 11203 may be configured to supply light in a predetermined wavelength band corresponding to special light observation. In special light observation, for example, by utilizing the wavelength dependence of light absorption in body tissue and irradiating with narrow-band light compared to the irradiation light used during normal observation (i.e., white light), so-called narrow-band imaging is performed to image predetermined tissues such as blood vessels on the surface of mucosa with high contrast. Alternatively, in special light observation, fluorescence observation may be performed to obtain an image from fluorescence generated by irradiation with excitation light. In fluorescence observation, excitation light is irradiated onto body tissue and fluorescence from the body tissue is observed (autofluorescence observation), or a reagent such as indocyanine green (ICG) is injected into body tissue and excitation light corresponding to the fluorescence wavelength of the reagent is irradiated onto the body tissue to obtain a fluorescence image. The light source device 11203 may be configured to supply narrow-band light and / or excitation light corresponding to such special light observation.

[0123] Figure 14 is a block diagram showing an example of the functional configuration of the camera head 11102 and CCU 11201 shown in Figure 13.

[0124] The camera head 11102 includes a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 includes a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other via a transmission cable 11400 so that they can communicate with each other.

[0125] The lens unit 11401 is an optical system provided at the connection point with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and then incident on the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses, including a zoom lens and a focus lens.

[0126] The imaging unit 11402 may consist of one image sensor (a so-called single-chip type) or multiple image sensors (a so-called multi-chip type). If the imaging unit 11402 is configured as a multi-chip type, for example, each image sensor may generate image signals corresponding to RGB, and these may be combined to obtain a color image. Alternatively, the imaging unit 11402 may be configured to have a pair of image sensors for acquiring image signals for the right eye and left eye, respectively, corresponding to 3D (dimensional) display. By performing 3D display, the surgeon 11131 can more accurately grasp the depth of the biological tissue in the surgical area. In addition, if the imaging unit 11402 is configured as a multi-chip type, multiple lens units 11401 may be provided corresponding to each image sensor.

[0127] Furthermore, the imaging unit 11402 does not necessarily have to be located on the camera head 11102. For example, the imaging unit 11402 may be located inside the lens barrel 11101, directly behind the objective lens.

[0128] The drive unit 11403 is composed of actuators and, under control from the camera head control unit 11405, moves the zoom lens and focus lens of the lens unit 11401 along the optical axis by a predetermined distance. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted as appropriate.

[0129] The communication unit 11404 is composed of communication devices for sending and receiving various types of information with 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.

[0130] Furthermore, the communication unit 11404 receives a control signal from the CCU 11201 to control the drive of the camera head 11102 and supplies it to the camera head control unit 11405. The control signal includes information about imaging conditions, such as 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.

[0131] The imaging conditions such as frame rate, exposure value, magnification, and focus may be specified by the user as appropriate, or they may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with so-called AE (Auto Exposure), AF (Auto Focus), and AWB (Auto White Balance) functions.

[0132] The camera head control unit 11405 controls the drive of the camera head 11102 based on the control signal received from the CCU 11201 via the communication unit 11404.

[0133] The communication unit 11411 is comprised of a communication device for sending and receiving various types of information with the camera head 11102. The communication unit 11411 receives image signals transmitted from the camera head 11102 via the transmission cable 11400.

[0134] Furthermore, the communication unit 11411 transmits control signals to the camera head 11102 to control the driving of the camera head 11102. Image signals and control signals can be transmitted by telecommunications, optical communications, etc.

[0135] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102.

[0136] The control unit 11413 performs various controls related to imaging the surgical area, etc., by the endoscope 11100, and the display of the images obtained from imaging the surgical area, etc. For example, the control unit 11413 generates a control signal to control the driving of the camera head 11102.

[0137] Furthermore, the control unit 11413 displays the captured image showing the surgical area, etc., on the display device 11202 based on the image signal processed 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 technologies. For example, the control unit 11413 can recognize surgical instruments such as forceps, specific biological sites, bleeding, mist when using the energy treatment device 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When the control unit 11413 displays the captured image on the display device 11202, it may use the recognition results to superimpose various surgical support information onto the image of the surgical area. By superimposing the surgical support information and presenting it to the surgeon 11131, the burden on the surgeon 11131 can be reduced, and the surgeon 11131 can proceed with the surgery reliably.

[0138] The 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 thereof.

[0139] In the illustrated example, communication was performed via a wired connection using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may be performed wirelessly.

[0140] The above describes an example of an endoscopic surgical system to which the technology of this disclosure may be applied. The technology of this disclosure can be applied to the configuration described above, for example, the endoscope 11100 and the camera head 11102. Specifically, for example, the light detection device 101 and the light detection device 201, each including the aforementioned pixels 10, can be applied to the imaging unit 11402. By applying the technology of this disclosure to the imaging unit 11402, it becomes possible to obtain the same effects as in the embodiments described above.

[0141] While an endoscopic surgical system has been described here as an example, the technology described herein may also be applied to other systems, such as microsurgical systems.

[0142] <5. Notes> The technology can also be configured as follows: (1) A photodetector comprising: a photoelectric conversion unit provided on a substrate that generates an electric charge corresponding to incident light by photoelectric conversion; a charge holding unit provided on the substrate that holds the electric charge; and a charge transfer unit provided on the substrate that transfers the electric charge from the photoelectric conversion unit to the charge holding unit, wherein the charge transfer unit includes a vertical gate electrode, and the vertical gate electrode includes a vertical electrode portion extending in the thickness direction of the substrate, and a horizontal electrode portion extending in a direction intersecting the thickness direction, wherein the length of the vertical electrode portion in plan view is at least twice the thickness of the horizontal electrode portion in cross-sectional view. (2) The photodetector according to (1), wherein the shape of the vertical electrode portion in plan view is a shape that extends in a predetermined direction, and the length of the vertical electrode portion in plan view is the length in the shorter direction of the vertical electrode portion in plan view. (3) The shape of the vertical electrode portion in plan view is elliptical, as described in (2). (4) The horizontal electrode portion includes a groove having depth in the thickness direction of the substrate, as described in any one of (1) to (3). (5) The length of the vertical electrode portion in plan view is the length in a direction perpendicular to the extension direction of the groove, as described in (4). (6) The depth of the groove in cross-sectional view is less than the thickness of the horizontal electrode portion in cross-sectional view, as described in (4) or (5). (7) The optical detection device according to any one of (4) to (6), further comprising a connecting portion provided on the substrate, wherein the connecting portion is formed to contact the vertical gate electrode from a position opposite to the groove. (8) The optical detection device according to any one of (1) to (7), wherein the vertical gate electrode is composed of an embedded member embedded in the substrate. (9) The photodetector according to (8), wherein the embedded member is made of any of polysilicon, tungsten, tantalum nitride, ruthenium oxide, titanium nitride, tungsten nitride, or iridium.(10) The photodetector according to any one of (1) to (9), further comprising an insulating film provided between the vertical gate electrode and the substrate, wherein the insulating film is formed of silicon oxide, silicon oxynitride, hafnium dioxide, zirconium dioxide, titanium dioxide, or aluminum oxide. (11) The photodetector comprising a photodetector, wherein the photodetector comprises: a photoelectric conversion unit provided on a substrate that generates an electric charge corresponding to incident light by photoelectric conversion; a charge holding unit provided on the substrate that holds the electric charge; and a charge transfer unit provided on the substrate that transfers the electric charge from the photoelectric conversion unit to the charge holding unit, wherein the charge transfer unit includes a vertical gate electrode, and the vertical gate electrode comprises: a vertical electrode portion extending in the thickness direction of the substrate; and a horizontal electrode portion extending in a direction intersecting the thickness direction, wherein the length of the vertical electrode portion in plan view is at least twice the thickness of the horizontal electrode portion in cross-sectional view. (12) The photodetector comprising a photodetector according to any one of (1) to (10). (13) A semiconductor device comprising any of the components of the light detection device described in any one of (1) to (10).

[0143] 10 Pixel 11 Vertical signal line 20 Substrate 20a Insulating film 20A Trench 21 Photoelectric conversion section 21a Semiconductor region 21b Semiconductor region 21c Semiconductor region 22 Charge holding section 22a Semiconductor region 23 Charge transfer section 24 Reset transistor 25 Amplifying transistor 26 Selecting transistor 30 Separation section 40 Insulating layer 50 Insulating layer 60 Wiring layer 61 Insulating layer 62 Wiring 63 Connection section 70 Color filter 80 On-chip lens 90 Vertical gate electrode 91 Vertical electrode section 92 Horizontal electrode section 92a Groove section 95 Embedded member 95a Groove section 96 Organic film X1 Length Z1 Thickness Z2 Depth

Claims

1. A light detection device comprising: a photoelectric conversion unit provided on a substrate that generates an electric charge corresponding to incident light by photoelectric conversion; a charge holding unit provided on the substrate that holds the electric charge; and a charge transfer unit provided on the substrate that transfers the electric charge from the photoelectric conversion unit to the charge holding unit, wherein the charge transfer unit includes a vertical gate electrode, the vertical gate electrode includes a vertical electrode portion extending in the thickness direction of the substrate, and a horizontal electrode portion extending in a direction intersecting the thickness direction, the length of the vertical electrode portion in plan view being at least twice the thickness of the horizontal electrode portion in cross-sectional view.

2. The photodetector according to claim 1, wherein the shape of the vertical electrode portion in plan view is a shape that extends in a predetermined direction, and the length of the vertical electrode portion in plan view is the length in the shorter direction of the vertical electrode portion in plan view.

3. The shape of the vertical electrode portion in plan view is elliptical, as described in claim 2.

4. The photodetector according to claim 1, wherein the horizontal electrode portion includes a groove having depth in the thickness direction of the substrate.

5. The photodetector according to claim 4, wherein the length of the vertical electrode portion in a plan view is the length in a direction perpendicular to the extension direction of the groove portion.

6. The optical detection device according to claim 4, wherein the depth of the groove in a cross-sectional view is smaller than the thickness of the horizontal electrode in a cross-sectional view.

7. The photodetector according to claim 4, further comprising a connecting portion provided on the substrate, wherein the connecting portion is formed to contact the vertical gate electrode from a position opposite to the groove.

8. The photodetector according to claim 1, wherein the vertical gate electrode is composed of an embedded member embedded in the substrate.

9. The photodetector according to claim 8, wherein the embedded member is formed of any of polysilicon, tungsten, tantalum nitride, ruthenium oxide, titanium nitride, tungsten nitride, or iridium.

10. The photodetector according to claim 1, further comprising an insulating film provided between the vertical gate electrode and the substrate, wherein the insulating film is formed of silicon oxide, silicon oxynitride, hafnium dioxide, zirconium dioxide, titanium dioxide, or aluminum oxide.

11. An electronic device comprising a photodetector, the photodetector comprising: a photoelectric conversion unit provided on a substrate and generating an electric charge corresponding to incident light by photoelectric conversion; a charge holding unit provided on the substrate and holding the electric charge; and a charge transfer unit provided on the substrate and transferring the electric charge from the photoelectric conversion unit to the charge holding unit, wherein the charge transfer unit includes a vertical gate electrode, the vertical gate electrode comprising: a vertical electrode portion extending in the thickness direction of the substrate; and a horizontal electrode portion extending in a direction intersecting the thickness direction, the length of the vertical electrode portion in plan view being at least twice the thickness of the horizontal electrode portion in cross-sectional view.

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