Light detection device

Abstract

A light detection device according to an embodiment includes a semiconductor layer, a floating diffusion, a vertical gate, and a semiconductor region. The semiconductor layer has a photodiode provided in the interior thereof. The floating diffusion is provided in the interior of the semiconductor layer at one surface side thereof. The vertical gate extends from the one surface side toward the interior of the semiconductor layer. The semiconductor region is formed of a semiconductor of a conductivity type opposite to the conductivity type of the photodiode, and covers the side surfaces and bottom surface of the vertical gate via a gate insulating film. In the semiconductor region, the width in a direction perpendicular to a plane equivalent to a plane having a crystal orientation of 110 in a plan view is smaller than the width in a direction perpendicular to a plane equivalent to a plane having a crystal orientation of 100 in a plan view.

Description

Photodetector

[0001] The present disclosure relates to a light detection device.

[0002] There is a photodetector device that includes a semiconductor layer in which a photodiode is provided, a floating diffusion provided inside the surface side of the semiconductor layer, and a vertical gate extending from the surface side of the semiconductor layer toward the inside of the semiconductor layer.

[0003] The photodiode photoelectrically converts the received light into a signal charge (e.g., electrons) corresponding to the amount of light. When a predetermined voltage is applied to the vertical gate, the photodetector detects light by transferring the signal charge from the photodiode to the floating diffusion.

[0004] In a photodetector device having a vertical gate, a semiconductor region of a conductivity type opposite to that of the photodiode is provided on the bottom surface of the vertical gate to passivate (pin) the interface state between the bottom surface of the vertical gate and the semiconductor layer.

[0005] One method for forming such a semiconductor region is to form a vertical hole in the semiconductor layer for forming a vertical gate, and then ion-implant impurities of a conductivity type opposite to that of the photodiode into the semiconductor layer from the bottom of the vertical hole.

[0006] In this method, impurities diffuse from the semiconductor region formed on the bottom surface of the vertical gate in the width direction of the vertical gate, which complicates the transfer path of the signal charge from the photodiode to the floating diffusion, degrading the signal charge transfer characteristics.

[0007] Therefore, as an alternative method, a semiconductor region is formed by growing an epitaxial layer of a conductivity type opposite to that of the photodiode on the inner surface of a vertical hole formed in a semiconductor layer (see, for example, Patent Document 1). With this method, a semiconductor region of a conductivity type opposite to that of the photodiode and of a uniform thickness can be formed so as to cover the side and bottom surfaces of the vertical gate.

[0008] JP 2011-014751 A

[0009] However, in the method of forming an epitaxial layer of the opposite conductivity type to that of the photodiode so as to cover the side and bottom surfaces of the vertical gate, if the impurity concentration of the epitaxial layer is made too low, pinning at the bottom surface of the vertical gate becomes insufficient.

[0010] For this reason, it is necessary to increase the impurity concentration of the epitaxial layer to an extent that pinning is possible, but this makes it difficult to form a channel on the side surface of the vertical gate, and the transfer characteristics of the signal charge deteriorate.

[0011] Therefore, the present disclosure provides a photodetector capable of improving the transfer characteristics of signal charges.

[0012] A photodetector according to an embodiment of the present disclosure includes a semiconductor layer, a floating diffusion, a vertical gate, and a semiconductor region. The semiconductor layer includes a photodiode therein. The floating diffusion is provided inside one surface side of the semiconductor layer. The vertical gate extends from the one surface side toward the inside of the semiconductor layer. The semiconductor region is formed of a semiconductor having an opposite conductivity type to that of the photodiode, and covers side and bottom surfaces of the vertical gate via a gate insulating film. The semiconductor region has a width in a direction perpendicular to a plane equivalent to a plane with a (110) crystal orientation in a plan view that is smaller than a width in a direction perpendicular to a plane equivalent to a (100) crystal orientation in a plan view.

[0013] 7 is an explanatory plan view of a photodetector according to a first example of the first embodiment. It is an explanatory cross-sectional view taken along line A-A' in FIG. 1. It is an explanatory plan view of a photodetector according to a second example of the first embodiment. It is an explanatory cross-sectional view taken along line B-B' in FIG. 3. It is an explanatory plan view of a photodetector according to a third example of the first embodiment. It is an explanatory cross-sectional view taken along line C-C' in FIG. 3. It is an explanatory cross-sectional view of a photodetector according to a fourth example of the first embodiment. It is an explanatory cross-sectional view taken along line D-D' in FIG. 7. It is an explanatory plan view of a photodetector according to a fifth example of the first embodiment. It is an explanatory plan view of a photodetector according to a sixth example of the first embodiment. It is an explanatory cross-sectional view, part 1, of a vertical gate according to a sixth example of the first embodiment. It is an explanatory cross-sectional view, part 2, of a vertical gate according to a sixth example of the first embodiment. It is an explanatory cross-sectional view showing an example of the shape of a vertical gate according to ... plan view of a photodetector according to a seventh example of the first embodiment. It is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the first embodiment. 26. FIG. 27 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the first embodiment. FIG. 28 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the first embodiment. FIG. 29 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the first embodiment. FIG. 29 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the first embodiment. FIG. 29 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the first embodiment. FIG. 29 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the first embodiment. FIG. 29 is an explanatory cross-sectional view showing a configuration example of a gate contact according to the second embodiment. 10A to 10C are cross-sectional explanatory views showing a manufacturing process of the photodetector according to the second embodiment.44. FIG. 45 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the second embodiment. FIG. 46 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the second embodiment. FIG. 47 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the second embodiment. FIG. 48 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the second embodiment. FIG. 49 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the second embodiment. FIG. 49 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the second embodiment. FIG. 49 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the second embodiment. FIG. 49 is an explanatory cross-sectional view showing a manufacturing process of the photodetector according to the second embodiment. FIG. 49 is an explanatory plan view showing an example of an arrangement of the photodetector according to the second embodiment. FIG. 49 is an explanatory cross-sectional view taken along line A-A' in FIG. 44. FIG. 49 is an explanatory plan view of a phase difference pixel including the photodetector according to the second embodiment. FIG. 49 is a schematic configuration diagram showing an example of a CMOS solid-state imaging device. FIG. 49 is a diagram illustrating an example of a schematic configuration of an image sensor according to an embodiment of the present disclosure. FIG. 50 is a diagram illustrating an example of the sensor pixel and readout circuit of FIG. 48. FIG. 51 is a block diagram showing an example of the configuration of an electronic device. FIG. 52 is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system. FIG. 53 is a block diagram illustrating an example of the functional configuration of a camera head and a CCU. FIG. 54 is a block diagram illustrating an example of a schematic configuration of a vehicle control system. FIG. 55 is an explanatory diagram showing an example of the installation positions of an outside vehicle information detection unit and an imaging unit.

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In each of the following embodiments, the same components and components that perform the same functions are designated by the same reference numerals, and redundant description will be omitted.

[0015] 1. First Embodiment 1-1. Photodetector according to First Example Fig. 1 is a plan view of a photodetector according to a first example of the first embodiment. Fig. 2 is a cross-sectional view taken along line AA' in Fig. 1.

[0016] The photodetector 1 is provided in a pixel array of a solid-state imaging device, such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor, which converts light from a subject into an electrical signal corresponding to the amount of received light. A plurality of photodetector devices 1 are arranged in a matrix on the light-receiving surface of the pixel array. Each photodetector device 1 captures one pixel of a captured image. FIG. 1 illustrates one photodetector device 1 corresponding to one pixel.

[0017] 1, the photodetector 1 includes a semiconductor layer 11, a floating diffusion (hereinafter referred to as "FD") 13, two gates 14A and 14B, and a well 15. The semiconductor layer 11 is, for example, a layer in which a silicon substrate is doped with a P-type impurity such as boron.

[0018] A photodiode (hereinafter referred to as "PD") 12 formed by doping an N-type impurity such as phosphorus is provided inside the semiconductor layer 11. The PD 12 is provided, for example, in the center of the semiconductor layer 11 in a plan view.

[0019] The semiconductor layer 11 is partitioned for each pixel by a pixel isolation region 10. The pixel isolation region 10 is, for example, a deep trench isolation (DTI) or a shallow trench isolation (STI) formed of silicon oxide.

[0020] The FD 13 is formed by doping an N-type impurity such as phosphorus inside one surface side of the semiconductor layer 11. The FD 13 is provided, for example, at one of the four corners of the semiconductor layer 11 separated by the pixel isolation region 10 in a plan view.

[0021] The well 15 is provided, for example, at a corner diagonally opposite the corner where the FD 13 is provided, among the four corners defined by the pixel isolation region 10 in the semiconductor layer 11 in a plan view. The well 15 is formed by doping the semiconductor layer 11 with an N-type impurity such as phosphorus.

[0022] The gates 14A and 14B are provided at a predetermined interval on both sides of a straight line connecting the corner where the FD 13 is provided and the corner where the Well 15 is provided. The gates 14A and 14B are configured to be symmetrical with respect to the straight line connecting the corner where the FD 13 is provided and the corner where the Well 15 is provided.

[0023] That is, the gates 14A and 14B have the same structure but different orientations. Therefore, the structure of the gate 14A will be described here, and a duplicated description of the gate 14B will be omitted. The gate 14A includes a gate electrode (hereinafter referred to as "TG") 21, a vertical gate (hereinafter referred to as "VG") 22, a gate insulating film 23, a sidewall (hereinafter referred to as "SW") 24, and a semiconductor region 25.

[0024] 2, the TG 21 is provided on one surface of the semiconductor layer 11. The TG 21 is made of, for example, polysilicon. The VG 22 extends from the bottom surface of the TG 21 toward the inside of the semiconductor layer 11. The VG 22 is made of, for example, polysilicon.

[0025] The gate insulating film 23 covers the side and bottom surfaces of the VG 22. The gate insulating film 23 is made of, for example, silicon oxide. The SW 24 is provided so as to surround the side surfaces of the TG 21. The portion of the SW 24 facing the FD 13 is provided so as to extend into the semiconductor layer 11. The SW 24 is made of, for example, silicon nitride.

[0026] The semiconductor region 25 covers the side and bottom surfaces of the VG 22 via the gate insulating film 23. The semiconductor region 25 is formed by epitaxially growing a semiconductor doped with impurities of the opposite conductivity type (P type) to the conductivity type (N type) of the PD 12.

[0027] If the concentration of the P-type impurity in the semiconductor region 25 is too low, the amount of P-type impurity will be insufficient, resulting in insufficient pinning at the bottom surface of VG 22. If the concentration of the P-type impurity in the semiconductor region 25 is too high, it will be difficult to form a channel in the region of VG 22 facing FD 13, resulting in deterioration of the transfer characteristics of the signal charge.

[0028] Therefore, the width of the semiconductor region 25 of the photodetector 1 in the direction perpendicular to a plane equivalent to a plane having a crystal orientation of 110 in a planar view (see Figure 1) is made smaller than the width in the direction perpendicular to a plane equivalent to a plane having a crystal orientation of 100 in a planar view (see Figure 1).

[0029] Therefore, the amount of P-type impurities in the portion of the semiconductor region 25 facing the FD 13 is smaller than the amount of P-type impurities in the portion other than the portion facing the FD 13. This makes it easier for a channel to be formed in the region of VG22 facing the FD 13 in the photodetector 1, thereby improving the transfer characteristics of signal charges.

[0030] Furthermore, the semiconductor region 25 is doped with a small amount of P-type impurities in the portion facing the FD13, so that free electrons generated due to the surface roughness of the interface between the portion facing the FD13 and the semiconductor layer 11 can be recombined with the P-type impurities, thereby suppressing the generation of dark current.

[0031] Furthermore, the amount of P-type impurities in the semiconductor region 25 is greater in the portion facing the well 15 and the portion covering the bottom surface of the VG22 than in the portion facing the FD 13. This allows the photodetector 1 to appropriately pin the interface between the semiconductor layer 11 and the portion of the semiconductor region 25 other than the portion facing the FD13, making it difficult for a channel to be formed in the region of the VG22 other than the side facing the FD13.

[0032] Therefore, the signal charge photoelectrically converted by the PD 12 (e shown in FIG. 2) - ) are less likely to move to the bottom side of VG 22 and the side of Well 15, and are smoothly transferred to FD 13 through a channel formed on the side of VG 22 facing FD 13. Therefore, the photodetector 1 can improve the transfer characteristics of signal charges.

[0033] When the semiconductor region 25 is epitaxially grown, it is generally formed at a temperature below 800°C. In this case, the film formation rate of the semiconductor region 25 is uniform and does not depend on the crystal orientation. For this reason, in this embodiment, the semiconductor region 25 is formed by epitaxial growth at a high temperature of 800°C to 850°C. This makes the film formation rate of the semiconductor region 25 dependent on the crystal orientation. As a result, the film thickness of the semiconductor region 25 on the plane with a 110 crystal orientation is smaller than the film thickness on the plane with a 100 crystal orientation.

[0034] Therefore, the semiconductor region 25 of the photodetector 1 is provided so that the surface facing the charge transfer path from PD 12 to FD 13 is equivalent to a surface with a crystal orientation of 110 in a plan view. As a result, in the photodetector 1, the film thickness of the portion of the semiconductor region 25 facing FD 13 is smaller than the film thickness of the other portions, which makes it easier to form a channel on the side of VG 22 facing FD 13, thereby improving the transfer efficiency of signal charges.

[0035] In plan view, the FD 13 of the photodetector 1 is provided on an imaginary line passing between the pair of VGs 22 shown in Fig. 1. The semiconductor region 25 has a surface covering the opposing side surfaces of the pair of VGs 22 that is equivalent to a surface with a crystal orientation of 110 in plan view.

[0036] Therefore, in the photodetector 1, the film thickness of the semiconductor region 25 in the portion covering the opposing surfaces of the pair of VGs 22 is smaller than the film thickness of other portions, which makes it easier for a channel to be formed in the region of the semiconductor layer 11 sandwiched between the pair of VGs 22, thereby improving the transfer characteristics of signal charges.

[0037] <1-2. Photodetector according to a second example> Fig. 3 is an explanatory plan view of a photodetector according to a second example of the first embodiment. Fig. 4 is an explanatory cross-sectional view taken along line BB' in Fig. 3. As shown in Fig. 3, the photodetector 1A according to the second example has a gate 14C instead of the gates 14A and 14B shown in Fig. 1.

[0038] One gate 14C is provided between the FD 13 and the well 15 in plan view. The VG22 of the gate 14C has a hexagonal shape in plan view, and is provided so that one of two opposing side surfaces faces the FD 13 and the other faces the well 15.

[0039] The semiconductor region 25 covering the side surface of the VG 22 is provided so that the crystal orientation of the surface facing the FD 13 in plan view and the surface facing the well 15 in plan view is 110.

[0040] Therefore, the film thickness of the semiconductor region 25 is smaller at a portion facing the FD 13 in a plan view and at a portion facing the well 15 in a plan view than at other portions. Also, as shown in FIG. 4 , the film thickness of the semiconductor region 25 covering the bottom surface of the VG 22 is larger than that of the portion facing the FD 13 in a plan view.

[0041] As a result, in the photodetector 1A, a channel is easily formed in the region between VG 22 and FD 13 in the semiconductor layer 11, and the transfer characteristics of signal charges can be improved.

[0042] In addition, in the photodetector 1A, the film thickness of the portion of the semiconductor region 25 facing the well 15 is relatively small when viewed in a plan view, but this portion is pinned by the P-type impurities doped into the well 15, so the transfer characteristics of the signal charge are not deteriorated.

[0043] <1-3. Photodetector according to a third example> Fig. 5 is an explanatory plan view of a photodetector according to a third example of the first embodiment. Fig. 6 is an explanatory cross-sectional view taken along line CC' in Fig. 3. Photodetector 1B according to the third example has gate 14D instead of gates 14A and 14B shown in Fig. 1.

[0044] The gate 14D includes one TG21 provided between the FD13 and the well 15 in a plan view, and two VG22 extending from the TG21 toward the inside of the semiconductor layer 11. The two VG22 are provided at a predetermined interval on both sides of an imaginary line connecting the FD13 and the well 15 in a plan view.

[0045] Each VG 22 has a rectangular shape in a plan view, and is provided so that its long sides face each other. This allows the photodetector 1B to form channels from both sides in the region sandwiched between the two VGs 22 in the semiconductor layer 11, thereby improving the signal charge transfer characteristics compared to when there is only one VG 22.

[0046] The semiconductor region 25 covering the side surfaces of the VG 22 is provided so that the crystal orientation of the surfaces that correspond to the long sides of the two VGs 22 in a planar view is 110. Therefore, the film thickness of the portions of the semiconductor region 25 that cover the surfaces that correspond to the long sides of the two VGs in a planar view is smaller than the film thickness of other portions. Also, as shown in FIG. 6 , the film thickness of the portion of the semiconductor region 25 that covers the bottom surface of the VG 22 is larger than the portion that faces the FD 13 in a planar view.

[0047] As a result, in the photodetector 1A, a channel is more likely to be formed in the region sandwiched between the two VGs 22 in the semiconductor layer 11, thereby improving the transfer characteristics of the signal charges. Note that in the photodetector 1B, the film thickness of the portion of the semiconductor region 25 facing the well 15 is relatively small in plan view, but this portion is pinned by the P-type impurity doped in the well 15, so the transfer characteristics of the signal charges do not deteriorate.

[0048] <1-4. Photodetector according to a fourth example> Fig. 7 is an explanatory plan view of a photodetector according to a fourth example of the first embodiment. Fig. 8 is an explanatory cross-sectional view taken along line DD' in Fig. 7. In the photodetector 1C according to the fourth example, the shape of VG22 differs from that shown in Figs. 5 and 6.

[0049] In the fourth embodiment, the gate 14D has one TG21 provided between the FD13 and the well 15 in a planar view, and two VG22 extending from the TG21 toward the inside of the semiconductor layer 11, but the planar shape of the VG22 is different from that of the VG22 in the third embodiment.

[0050] The two VGs 22 in the fourth embodiment have a pentagonal shape in a plan view, and are provided so that the opposing surfaces are parallel. The two VGs 22 are provided so that the crystal orientation of the opposing side surfaces is 110. As a result, the crystal orientation of the side surfaces and bottom surfaces of the two VGs 22 other than the opposing side surfaces is 100.

[0051] Therefore, in plan view, the film thickness of the semiconductor region 25 is smaller in the portion covering the opposing side surfaces of the two VGs 22 than in the other portions. Also, as shown in Fig. 7, the film thickness of the semiconductor region 25 is larger in the portion covering the bottom surfaces of the VGs 22 than in the portion covering the opposing side surfaces of the two VGs 22. This makes it easier for a channel to be formed in the region of the semiconductor layer 11 sandwiched between the two VGs 22 in the photodetector 1C, thereby improving the transfer characteristics of signal charges.

[0052] Moreover, the film thickness of the semiconductor region 25 in a plan view, covering the side surfaces other than the side surfaces facing each other of the two VGs 22, is greater than the film thickness of the portion covering the side surfaces facing each other of the two VGs 22. This makes it difficult for channels to be formed in the semiconductor layer 11 other than the region sandwiched between the two VGs 22 in the photodetector 1C, thereby further improving the transfer characteristics of the signal charges.

[0053] In addition, in the photodetector 1B, the film thickness of the portion of the semiconductor region 25 facing the well 15 is relatively small when viewed in a plan view, but this portion is pinned by the P-type impurities doped into the well 15, so the transfer characteristics of the signal charge are not deteriorated.

[0054] <1-5. Photodetector according to a fifth example> Figure 9 is an explanatory plan view of a photodetector according to a fifth example of the first embodiment. As shown in Figure 9, in a photodetector 1D according to the fifth example, FDs 13 are provided at the intersections of pixel isolation regions 10 that divide the semiconductor layer 11 into a lattice pattern. This allows the photodetector 1D to expand the area in the semiconductor layer 11 that can be used as PDs 12 compared to the photodetector 1 shown in Figure 1, thereby improving the sensitivity of photodetection.

[0055] Furthermore, in the photodetector device 1D, a transistor 16 is provided on the semiconductor layer 11 of each pixel partitioned by the pixel isolation region 10. The transistor 16 is, for example, an amplifier transistor that amplifies a signal corresponding to the signal charge transferred to the FD 13, and a reset transistor that resets the signal charge transferred to the FD 13. This allows the photodetector device 1D to occupy a smaller area than when the transistor 16 is provided outside the pixel region.

[0056] The gates 14A and 14B of the photodetector 1D have the same configuration as those shown in Fig. 1. Therefore, the photodetector 1D can improve the transfer characteristics of signal charges, similar to the first to fourth embodiments.

[0057] <1-6. Photodetector according to Sixth Example> Fig. 10 is a plan view of a photodetector according to a sixth example of the first embodiment. Fig. 11 is a first cross-sectional view of a vertical gate according to the sixth example of the first embodiment. Fig. 12 is a second cross-sectional view of a vertical gate according to the sixth example of the first embodiment.

[0058] As shown in FIG. 10, the photodetector 1E of the sixth embodiment differs from the fifth embodiment in that gates 14A and 14B, which are triangular in plan view, are provided so that one side surface thereof contacts the pixel isolation region 10.

[0059] This allows the photodetector 1E to further improve the transfer characteristics of signal charges by preventing the signal charges photoelectrically converted by the PD 12 from getting lost between the gates 14A, 14B and the pixel isolation region 10 and not being transferred to the FD 13.

[0060] The gates 14A and 14B may have a configuration like the gate 14F shown in Fig. 11 or a configuration like the gate 14G shown in Fig. 12. As shown in Fig. 11, the gate 14F does not have, for example, TG21, and has a configuration in which the gate contact 17 is directly connected to VG22.

[0061] In this case, the SW24 is provided on a portion of the side surface of the gate contact 17 that is deeper than the top surface of the pixel isolation region 10. The area occupied by the gate 14F shown in Fig. 11 is reduced by the amount corresponding to the absence of the TG21. This allows the photodetector 1E to be miniaturized.

[0062] 12, the gate 14G is configured such that a part of the TG21 provided on the VG22 extends onto the pixel isolation region 10. The gate 14F has a gate contact 17 connected to the TG21.

[0063] In the gate 14G shown in FIG. 12, the gate contact 17 is connected to TG21 which has a larger area than VG22, so even if the position of the gate contact 17 is slightly misaligned, TG21 and the gate contact 17 are reliably connected.

[0064] 13 to 15 are cross-sectional views illustrating examples of the shape of the vertical gate according to the first embodiment. Note that components other than the VG 22 and the semiconductor region 25 are not shown in FIGS.

[0065] The cross-sectional shape of VG22 when the semiconductor layer 11 is cut in a direction perpendicular to the surface direction may be a rectangular shape as shown in Fig. 2, or may be a cross-sectional shape as shown in Fig. 13 to Fig. 15. For example, as shown in Fig. 13, VG22 may be a trapezoidal shape that narrows as the depth position in the semiconductor layer 11 increases.

[0066] 14, VG22 may have a rounded rectangular shape with no corners where the side surface and bottom surface are connected, or may have a rounded triangular shape with a width that narrows as the depth position in the semiconductor layer 11 increases, as shown in FIG.

[0067] In either case, the semiconductor region 25 has a shape that conforms to the side and bottom surfaces of the VG 22. In either case, however, the semiconductor region 25 is provided so that the crystal orientation of the surface facing the FD 13 is 110.

[0068] As a result, in the photodetector, the thickness of the portion of the semiconductor region 25 facing FD13 is thinner than the thickness of the other portions, making it easier for a channel to be formed on the side of VG22 facing FD13, thereby improving the transfer characteristics of signal charges.

[0069] <1-8. Photodetector according to a seventh example> Fig. 16 is an explanatory plan view of a photodetector according to a seventh example of the first embodiment. As shown in Fig. 16, in the photodetector 1F, the semiconductor layer 11 is divided into unit pixels (one pixel) by pixel isolation regions 10 (first pixel isolation regions). Furthermore, in the photodetector 1F, each semiconductor layer 11 corresponding to a unit pixel is divided into a pair of phase difference pixels by a pixel isolation region 10A (second pixel isolation region).

[0070] Each phase difference pixel is provided with a gate 14G shown in Fig. 12. In addition, an FD 13 is provided between two gates 14G, and a well 15 is provided at a position facing the FD 13 across the semiconductor layer 11 in the unit pixel in plan view.

[0071] The photodetector 1F is applied to, for example, an imaging device that performs autofocus control by utilizing the difference between the phase of light incident on one of a pair of phase difference pixels and the phase of light incident on the other. The pair of gates included in the photodetector 1F may be the gates according to the first to sixth embodiments. This allows the photodetector 1F to improve the transfer characteristics of signal charges, similar to the first to sixth embodiments.

[0072] 17 to 21 are cross-sectional explanatory views showing the manufacturing process of the photodetector according to the first embodiment. Here, the gate formation process will be described, and the manufacturing processes of the other components will not be described because known processes can be used.

[0073] 17, when manufacturing the photodetector 1 according to the first embodiment, for example, a silicon substrate is doped with a P-type impurity such as boron to form a semiconductor layer 11. Then, the semiconductor layer 11 is partitioned into individual pixels by pixel isolation regions 10.

[0074] Thereafter, ions of an N-type impurity such as phosphorus are implanted into each semiconductor layer partitioned for each pixel, and heat treatment is performed to form PDs 12 inside the semiconductor layer 11. Subsequently, the surface of the semiconductor layer 11 is oxidized to form a silicon oxide film 26, and a silicon nitride film 27 is formed on the surface of the silicon oxide film 26, thereby generating a hard mask made of the silicon oxide film 26 and the silicon nitride film 27 on the semiconductor layer 11.

[0075] Thereafter, an opening is formed in the hard mask at a position where VG 22 is to be formed, and the semiconductor layer 11 is excavated from the opening in the hard mask to form a vertical hole for forming VG 22. Next, as shown in Fig. 18, a P-type semiconductor region 25 containing P-type impurities such as boron is epitaxially grown on the side and bottom surfaces of the vertical hole.

[0076] At this time, the semiconductor region 25 is epitaxially grown at a high temperature of, for example, 800° C. to 850° C. As a result, the film formation rate of the semiconductor region 25 depends on the crystal orientation, and therefore the width in the direction perpendicular to a plane equivalent to a plane with a crystal orientation of 110 in plan view becomes smaller than the width in the direction perpendicular to a plane equivalent to a plane with a crystal orientation of 100 in plan view.

[0077] Thereafter, as shown in Fig. 19, the hard mask is removed. Next, a gate insulating film 23 is formed on the inner circumferential surface and bottom surface of the vertical hole in which the semiconductor region 25 is formed. Next, as shown in Fig. 20, VG 22 and TG 21 are formed by filling, for example, polysilicon into the vertical hole in which the gate insulating film 23 has been formed. Finally, as shown in Fig. 21, SW 24 is formed of, for example, silicon nitride so as to surround the side surface of TG 21, thereby completing the photodetector 1.

[0078] <2. Second Embodiment> <2-1. Photodetector According to First Example> The photodetector according to the second embodiment differs from that according to the first embodiment in the configuration of the gate. Therefore, the following will describe the configuration of the gate according to the second embodiment, and will omit descriptions of the other components.

[0079] Fig. 22 is a cross-sectional explanatory diagram of a photodetector according to a first example of the second embodiment. Fig. 23 is an enlarged explanatory diagram of the area within the dashed line frame shown in Fig. 22. Fig. 24 is a cross-sectional explanatory diagram taken along line A-A' in Fig. 22. Fig. 25 is a cross-sectional explanatory diagram taken along line B-B' in Fig. 22.

[0080] 21 to 25, the photodetector 3 according to the first example includes a VG 31 that extends from one surface side of the semiconductor layer 30 toward the inside of the semiconductor layer 30. As in the first embodiment, a PD is provided inside the semiconductor layer 30. Furthermore, an FD is provided inside the semiconductor layer 30 on one surface side.

[0081] The photodetector 3 also includes a semiconductor region 33 formed of a semiconductor of an opposite conductivity type (P type in this case) to the conductivity type of the PD (N type in this case). The semiconductor region 33 covers the side and bottom surfaces of the VG 31 via the gate insulating film 32. The semiconductor region 33 is formed by epitaxially growing a semiconductor doped with impurities of the opposite conductivity type (P type) to the conductivity type of the PD (N type).

[0082] As explained in the first embodiment, if the concentration of P-type impurities in the semiconductor region 33 is too low, the amount of P-type impurities will be insufficient, resulting in insufficient pinning at the bottom surface of VG 31. If the concentration of P-type impurities in the semiconductor region 33 is too high, it will be difficult to form a channel in the region facing the FD of VG 31, and the transfer characteristics of the signal charge will deteriorate.

[0083] Therefore, in the semiconductor region 33 according to the second embodiment, the P-type impurity concentration in the first region 34 facing the bottom surface of VG31 is higher than the P-type impurity concentration in the second region 35 covering the side surface of VG31 and the first region 34. This allows the bottom surface of VG31 to be appropriately pinned in the photodetector 3, and also makes it easier for a channel to be formed in the region of VG31 facing the FD, thereby improving the transfer characteristics of signal charges.

[0084] Furthermore, the first region 34 of the semiconductor region 33 has a width smaller than that of the structure including VG31 and the second region 35 of the semiconductor region 33. This allows the photodetector 3 to suppress diffusion of P-type impurities from the first region 34 in the width direction of VG31.

[0085] Furthermore, a gap 36 exists between the interface with the semiconductor layer 30 in the second region 35 of the semiconductor region 33, in the portion covering the side surface of the first region 34, and the interface with the first region 34. This allows the photodetector 3 to suppress the diffusion of P-type impurities from the first region 34 in the width direction of VG31.

[0086] Specifically, the second region 35 is formed by epitaxial growth from the surface of the first region 34 and the inner surface of the vertical hole, as shown by the black arrow in Figure 23, after the first region 34 is formed at the bottom of the vertical hole formed in the semiconductor layer 30.

[0087] At this time, before the second region 35 growing from the side of the first region 34 joins with the second region 35 growing from the inner surface of the vertical hole, a void 36 is formed when the second region 35 growing from the top surface of the first region 34 joins with the second region 35 growing from the inner surface of the vertical hole.

[0088] According to such semiconductor region 33, as shown by the white arrow in FIG. 23, P-type impurities are diffused by heat from the first region 34 in the depth direction of the semiconductor layer 30, so that the bottom of the vertical hole can be pinned appropriately.

[0089] As a result, free electrons generated due to the surface roughness of the bottom surface of the vertical hole during the process of forming the vertical hole are recombined with P-type impurities diffusing from the first region 34 in the depth direction of the semiconductor layer 30. As a result, the photodetector 3 can suppress the generation of dark current.

[0090] Furthermore, in this semiconductor region 33, the P-type impurity tends to diffuse due to heat from the first region 34 in a direction parallel to the width direction of the VG 31, but the voids 36 prevent the thermal diffusion of the P-type impurity.

[0091] As a result, the photodetector 3 does not have a complex side shape of the semiconductor region 33, but has a flat shape that follows the side shape of VG31, so the transfer path of the signal charge becomes a linear path that follows the side shape of the semiconductor region 33, thereby improving the transfer characteristics of the signal charge.

[0092] <2-2. Photodetector according to second example> Fig. 26 is a cross-sectional view of a photodetector according to a second example of the second embodiment. Fig. 27 is a cross-sectional view taken along line A-A' in Fig. 26. Fig. 28 is a cross-sectional view taken along line B-B' in Fig. 26.

[0093] 26 to 28, in the photodetector 3A of the second embodiment, there are no voids 36 (see FIGS. 23 and 25) in the second region 35 of the semiconductor region 33, but there are crystal defects 37. Specifically, in the second region 35 of the second embodiment, there are crystal defects 37 between the interface with the semiconductor layer 30 in the portion covering the side surface of the first region 34 and the interface with the first region 34. The crystal defects 37 are formed at the portion where the second region 35 growing from the side surface and top surface of the first region 34 and the second region 35 growing from the inner circumferential surface of the vertical hole join together.

[0094] As a result, the photodetector 3A can suppress the diffusion of P-type impurities from the first region 34 in the width direction of the VG 31 due to the crystal defects 37, just as in the case where the voids 36 are present. Therefore, the photodetector 3A can improve the transfer characteristics of signal charges while suppressing the generation of dark current, just like the first embodiment.

[0095] <2-3. Photodetector according to third example> Fig. 29 is a cross-sectional view of a photodetector according to a third example of the second embodiment. Fig. 30 is a cross-sectional view taken along line A-A' in Fig. 29. Fig. 31 is a cross-sectional view taken along line B-B' in Fig. 29.

[0096] As shown in FIGS. 29 to 31, in the photodetector 3B of the second embodiment, there is no void 36 (see FIGS. 23 and 25) in the second region 35 of the semiconductor region 33, and the gate insulating film 32 extends therethrough.

[0097] Specifically, as shown in FIG. 29, the gate insulating film 32 of the third embodiment has a first portion 41 covering the side surface of VG31, a second portion 42 covering the bottom surface of VG31, and a third portion 43 extending from the first portion 41 to surround the side surface of the first region 34 in the semiconductor region 33.

[0098] As a result, in the photodetector 3A, similar to the case where the void 36 is present, the third portion 43 of the gate insulating film 32 can suppress the diffusion of P-type impurities from the first region 34 in the width direction of VG31. Therefore, similar to the first embodiment, the photodetector 3A can improve the transfer characteristics of signal charges while suppressing the generation of dark current.

[0099] 32 to 34 are cross-sectional views showing examples of vertical gate arrangements according to the second embodiment. Fig. 35 is a cross-sectional view showing an example of the configuration of a gate contact according to the second embodiment.

[0100] 32 , the photodetector 3 of the first embodiment may be configured so that the second region 35 of the semiconductor region 33 covering one side surface of the VG 31 is provided at a predetermined distance from the pixel isolation region 50. In this case, a SW 44 made of, for example, silicon nitride is provided around the portion of the VG 31 that protrudes from the surface of the semiconductor layer 30.

[0101] 33 , the second region 35 of the semiconductor region 33 covering one side surface of VG31 may be configured to be in contact with the pixel isolation region 50. In this case, the portion of VG31 protruding from the surface of the semiconductor layer 30 extends to the surface of the pixel isolation region 50. Then, around the portion of VG31 protruding from the surface of the semiconductor layer 30, an SW44 made of, for example, silicon nitride is provided.

[0102] 34, two VGs 31 may be provided in the semiconductor layer 30 constituting one pixel. In this case, the portion of VG 31 protruding from the surface of the semiconductor layer 30 may be configured to extend to the surface of the pixel isolation region 50, similar to that shown in FIG.

[0103] 35, VG31 may be embedded inside the semiconductor layer 30. In this case, VG31 is directly connected to a gate contact 47 made of, for example, polysilicon. Note that the side surface of the gate contact 47 is covered with SW46 made of, for example, silicon.

[0104] 36 to 43 are cross-sectional explanatory views showing the manufacturing process of the photodetector according to the second embodiment. Here, the gate formation process will be described, and the manufacturing processes of the other components will not be described because known processes can be used.

[0105] When manufacturing the photodetector 1 according to the second embodiment, a vertical hole is formed at the position where VG31 is to be formed in the semiconductor layer 30 where PD and FD have already been formed, as shown in Fig. 36. Then, SW48 is formed on the inner surface of the vertical hole using, for example, silicon oxide or silicon nitride, as shown in Fig. 37.

[0106] Thereafter, a first region 34 of a semiconductor region 33 containing a relatively high concentration of P-type impurities is formed by epitaxial growth on the bottom surface of the vertical hole, as shown in Fig. 38. Subsequently, SW 48 is peeled off, as shown in Fig. 39.

[0107] 40, second region 35 of semiconductor region 33 containing a relatively low concentration of P-type impurities is formed by epitaxial growth from the exposed inner side and bottom surfaces of the vertical hole and the side and top surfaces of first region 34. As a result, void 36 is formed in the portion of second region 35 covering the side surface of first region 34.

[0108] At this time, depending on the shape of first region 34, crystal defects 37 (see FIG. 26 ) are formed instead of voids 36 at the positions where voids 36 would be formed. For example, if the area of ​​the top surface of first region 34 is smaller than the area of ​​the bottom surface and the cross-sectional shape of first region 34 is trapezoidal, crystal defects 37 are formed instead of voids 36.

[0109] 41 , a gate insulating film 32 is then formed on the inner side and bottom surfaces of the vertical hole covered by the second region 35 of the semiconductor region 33. Finally, VG 31 is formed by embedding, for example, polysilicon inside the vertical hole covered by the gate insulating film 32. In this manner, the photodetector 3 of the first embodiment or the photodetector 3A of the second embodiment is manufactured.

[0110] Furthermore, when manufacturing the photodetector 3B of the third embodiment, epitaxial growth of the semiconductor region 33 is started from the state shown in Fig. 39. Then, epitaxial growth of the semiconductor region 33 is terminated before the portion of the second region 35 covering the side surface of the first region 34 comes into contact with the portion covering the inner surface of the vertical hole.

[0111] As a result, a slit is formed so as to surround the side surface of the first region 34, as shown in Fig. 42. Thereafter, as shown in Fig. 43, a gate insulating film 32 is formed on the inner side surface and bottom surface of the vertical hole including the slit. This forms a first portion 41, a second portion 42, and a third portion 43 of the gate insulating film 32. In this way, the photodetector 3B of the third embodiment is manufactured.

[0112] <2-6. Arrangement example of photodetection device according to second embodiment> Fig. 44 is an explanatory plan view showing an arrangement example of the photodetection device according to the second embodiment. Fig. 45 is an explanatory cross-sectional view taken along line A-A' in Fig. 44. Fig. 46 is an explanatory plan view of a phase difference pixel including the photodetection device according to the second embodiment.

[0113] As shown in Fig. 44 and Fig. 45, the photodetectors 3 are arranged in a matrix. Note that in Fig. 44, the photodetectors 3 of four pixels arranged vertically and horizontally are arranged so that the FDs 51 provided at one of the four corners are concentrated in the center.

[0114] Each photodetector 3 has a PD provided inside each semiconductor layer 30. Each photodetector 3 has a VG 31 provided at a predetermined distance from the FD 51, close to one of the four corners where the FD 51 is provided. As shown in FIG. 45 , a fixed charge film 53 doped with P-type impurities is provided between the PD 52 and the pixel isolation region 50.

[0115] The photodetector 3 may also be applied to a phase difference pixel. In this case, for example, as shown in FIG. 46 , two photodetectors 3 are arranged in each of four pixels 9 arranged vertically and horizontally. The photodetector 3 constituting each phase difference pixel is provided with an FD 51, a PD 52 (see FIG. 45 ), and a VG 31. The photodetector 3 is applied to, for example, an imaging device that performs autofocus control by utilizing the difference between the phase of light incident on one of a pair of phase difference pixels and the phase of light incident on the other.

[0116] 3. Application Example to CMOS Solid-State Imaging Device The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to a CMOS solid-state imaging device.

[0117] FIG. 47 shows a schematic configuration of an example of a CMOS solid-state imaging device. As shown in FIG. 47, the photodetector 101 of this example includes a pixel section (so-called imaging region) 103 in which pixels 102, each including a plurality of photoelectric conversion elements, are regularly arranged two-dimensionally on a semiconductor substrate 111, e.g., a silicon substrate, and a peripheral circuit section. Each pixel 102 may be a photodetector device (e.g., the photodetector device 1, etc.) having one of the configurations described above. Each pixel 102 includes a photoelectric conversion element, e.g., a PD, and a plurality of pixel transistors (so-called MOS transistors). The plurality of pixel transistors may be configured with, for example, three transistors: a transfer transistor, a reset transistor, and an amplifier transistor. Alternatively, a selection transistor may be added to form a four-transistor configuration. The equivalent circuit of a unit pixel is similar to that of a conventional pixel, and therefore a detailed description thereof will be omitted. The pixel 102 may also have a shared pixel structure. This pixel-sharing structure includes a plurality of PDs, a plurality of transfer transistors, a shared FD, and each of the other shared pixel transistors.

[0118] The peripheral circuit section includes 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.

[0119] The control circuit 108 receives an input clock and data instructing the operation mode, etc., and outputs data such as internal information of the solid-state imaging device. That is, the control circuit 108 generates clock signals and control signals that serve as references for the operations of the vertical drive circuit 104, column signal processing circuit 105, horizontal drive circuit 106, etc., based on a vertical synchronization signal, a horizontal synchronization signal, and a master clock. These signals are then input to the vertical drive circuit 104, column signal processing circuit 105, horizontal drive circuit 106, etc.

[0120] The vertical drive circuit 104 is configured by, for example, a shift register, selects pixel drive wirings, supplies pulses for driving pixels to the selected pixel drive wirings, and drives the pixels row by row. That is, the vertical drive circuit 104 selects and scans each pixel 102 of the pixel unit 103 row by row in the vertical direction, and supplies pixel signals based on signal charges generated in, for example, PDs serving as photoelectric conversion elements of each pixel 102 according to the amount of light received to the column signal processing circuit 105 via vertical signal lines 109.

[0121] The column signal processing circuits 105 are arranged, for example, for each column of the pixels 102, and perform signal processing such as noise removal for each pixel column on signals output from one row of the pixels 102. That is, the column signal processing circuits 105 perform signal processing such as CDS for removing fixed pattern noise specific to the 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 and connected between the output stage and the horizontal signal line 110.

[0122] 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 turn, causing each of the column signal processing circuits 105 to output a pixel signal to a horizontal signal line 110.

[0123] The output circuit 107 processes and outputs signals sequentially supplied from each of the column signal processing circuits 105 via a horizontal signal line 110. For example, the output circuit 107 may perform only buffering, or may perform black level adjustment, column variation correction, various digital signal processing, etc. The input / output terminal 112 exchanges signals with the outside.

[0124] 4. Application Example to Image Sensor The technology according to the present disclosure may be applied to an image sensor. FIG. 48 illustrates an example of a schematic configuration of an image sensor 201 according to the present disclosure. The image sensor 201 includes three substrates (a first substrate 210, a second substrate 220, and a third substrate 230). The image sensor 201 has a three-dimensional structure formed by bonding together the three substrates (the first substrate 210, the second substrate 220, and the third substrate 230). The first substrate 210, the second substrate 220, and the third substrate 230 are stacked in this order.

[0125] The first substrate 210 has a semiconductor substrate 211 on which a plurality of sensor pixels 212 that perform photoelectric conversion are mounted. The sensor pixels 212 may be, for example, a photodetector device having any of the configurations described above (e.g., the photodetector device 1, etc.). The sensor pixels 212 are arranged in a matrix within a pixel region 213 on the first substrate 210. The second substrate 220 has, on its semiconductor substrate 221, readout circuits 222 for every four sensor pixels 212. The readout circuits 222 output pixel signals based on the charges 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, on its semiconductor substrate 231, a logic circuit 232 that processes pixel signals. The logic circuit 232 has, 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 of each sensor pixel 212 to the outside. In the logic circuit 232, for example, CoSi ２Alternatively, a low resistance region made of silicide such as NiSi or NiAl may be formed using a salicide (Self Aligned Silicide) process.

[0126] The vertical drive circuit 233, for example, sequentially selects the plurality of sensor pixels 212 row by row. The column signal processing circuit 234, for example, performs correlated double sampling (CDS) processing on pixel signals output from each sensor pixel 212 in the row selected by the vertical drive circuit 233. The column signal processing circuit 234 extracts signal levels of the pixel signals by performing CDS processing, for example, and stores 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 stored in the column signal processing circuit 234 to the outside. The system control circuit 236, for example, controls the driving of each block (the vertical drive circuit 233, the column signal processing circuit 234, and the horizontal drive circuit 235) in the logic circuit 232.

[0127] Fig. 49 shows an example of the sensor pixels 212 and the readout circuit 222. Below, a case will be described in which four sensor pixels 212 share one readout circuit 222, as shown in Fig. 49. Here, "shared" means that the outputs of the four sensor pixels 212 are input to the common readout circuit 222.

[0128] The sensor pixels 212 have common components. In Fig. 49, in order to distinguish the components of the sensor pixels 212 from one another, an identification number (1, 2, 3, 4) is added to the end of the reference numeral of the component of each sensor pixel 212. Hereinafter, when it is necessary to distinguish the components of each sensor pixel 212 from one another, an identification number is added to the end of the reference numeral of the component of each sensor pixel 212. 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 reference numeral of the component of each sensor pixel 212 is omitted.

[0129] 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 a specific example of a "photoelectric conversion element" in the present disclosure. The photodiode PD performs photoelectric conversion to generate a charge corresponding to the amount of received light. 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). 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. The transfer transistor TR is, for example, a CMOS transistor.

[0130] The floating diffusions FD of the sensor pixels 212 that share one readout circuit 222 are electrically connected to each other and 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. Note that 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 supply 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 FIG. 48). 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 a vertical signal line 224, and the gate of the selection transistor SEL is electrically connected to a pixel drive line 223 (see FIG. 48).

[0131] When the transfer transistor TR is turned on, it transfers the charge of 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 supply 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 pixel signal with a voltage corresponding to the level of the charge held in the floating diffusion FD. The amplification transistor AMP constitutes a source follower amplifier and outputs a pixel signal with a voltage corresponding to the level of the 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 the amplified 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.

[0132] 5. Application Examples to Electronic Devices The photodetector device as described above can be 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.

[0133] FIG. 50 is a block diagram showing an example of the configuration of an electronic device.

[0134] As shown in Figure 50, the imaging device 301 includes an optical system 302, a photodetector 303, and a DSP (Digital Signal Processor) 304, and is configured by connecting the DSP 304, a display device 305, an operation system 306, a memory 308, a recording device 309, and a power supply system 310 via a bus 307, and is capable of capturing still images and moving images.

[0135] The optical system 302 is configured to have one or more lenses, and guides image light (incident light) from a subject to the photodetector 303 , forming an image on the light receiving surface (sensor portion) of the photodetector 303 .

[0136] The photodetector 303 may be any of the photodetector devices having the above-described configuration examples (for example, the photodetector 1, etc.). Electrons are accumulated in the photodetector 303 for a certain period of time in accordance with an image formed on the light-receiving surface via the optical system 302. A signal corresponding to the electrons accumulated in the photodetector 303 is then supplied to the DSP 304.

[0137] The DSP 304 performs various signal processing on the signal from the photodetector 303 to acquire an image, and temporarily stores the image data in a memory 308. The image data stored in the memory 308 is recorded in a recording device 309 or supplied to a display device 305 to display the image. In addition, an operation system 306 accepts various operations by a user and supplies operation signals to each block of the imaging device 301, and a power supply system 310 supplies power necessary to drive each block of the imaging device 301.

[0138] 6. Application Example to Endoscopic Surgery System The technology according to the present disclosure may be applied to an endoscopic surgery system. Fig. 51 is a diagram showing an example of a schematic configuration of an endoscopic surgery system to which the technology according to the present disclosure (the present technology) can be applied.

[0139] Figure 51 shows an operator (doctor) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 is composed of an endoscope 11100, other surgical tools 11110 such as an insufflation tube 11111 and an energy treatment tool 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

[0140] The endoscope 11100 is composed of a lens barrel 11101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 11132, and a camera head 11102 connected to the base end of the lens barrel 11101. In the example shown, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible scope having a flexible lens barrel.

[0141] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 11101. 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 by a light guide extending inside the lens barrel 11101, and is irradiated via the objective lens toward an object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0142] An optical system and an image sensor are provided inside the camera head 11102, and light reflected from the object of observation (observation light) is collected onto the image sensor by the optical system. The image sensor photoelectrically converts the observation light to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is sent to a camera control unit (CCU) 11201 as RAW data.

[0143] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and comprehensively controls the operations 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 types of image processing on the image signal, such as development processing (demosaic processing), to display an image based on the image signal.

[0144] Under the control of the CCU 11201, the display device 11202 displays an image based on an image signal that has been subjected to image processing by the CCU 11201.

[0145] The light source device 11203 is composed of a light source such as an LED (light emitting diode), and supplies the endoscope 11100 with irradiation light when photographing the surgical site, etc.

[0146] The input device 11204 is an input interface for the endoscopic surgery system 11000. A 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 to change the imaging conditions (type of irradiation light, magnification, focal length, etc.) of the endoscope 11100.

[0147] The treatment tool control device 11205 controls the driving of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 inflates the body cavity of the patient 11132 through the insufflation tube 11111 in order to ensure a clear field of view for the endoscope 11100 and a working space for the surgeon. The recorder 11207 is a device capable of recording various types of information related to the surgery. The printer 11208 is a device capable of printing various types of information related to the surgery in various formats such as text, images, or graphs.

[0148] The light source device 11203, which supplies illumination light to the endoscope 11100 when photographing the surgical site, can be configured from a white light source, such as an LED, a laser light source, or a combination of these. When the white light source is configured from a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, allowing the light source device 11203 to adjust the white balance of the captured image. In this case, it is also possible to time-share images corresponding to each RGB by irradiating the object of observation with laser light from each RGB laser light source and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, color images can be obtained without providing a color filter to the image sensor.

[0149] Furthermore, the light source device 11203 may be controlled to change the intensity of light it outputs at predetermined time intervals. By controlling the driving of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity to acquire images in a time-division manner and combining the images, it is possible to generate an image with a high dynamic range that is free from so-called blocked-up shadows and blown-out highlights.

[0150] The light source device 11203 may also be configured to supply light in a predetermined wavelength band corresponding to special light observation. Special light observation, for example, utilizes the wavelength dependence of light absorption in body tissues to irradiate a specific tissue, such as blood vessels on the surface of the mucosa, with light in a narrower band than the light irradiated during normal observation (i.e., white light), thereby performing so-called narrow band imaging. Alternatively, special light observation may be performed using fluorescence observation, in which images are obtained using fluorescence generated by irradiating excitation light. Fluorescence observation may involve irradiating excitation light onto body tissue and observing the fluorescence from the tissue (autofluorescence observation), or by locally injecting a reagent such as indocyanine green (ICG) into the body tissue and irradiating the tissue with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 11203 may be configured to supply narrow band light and / or excitation light corresponding to such special light observation.

[0151] FIG. 52 is a block diagram showing an example of the functional configuration of the camera head 11102 and the CCU 11201 shown in FIG.

[0152] The camera head 11102 has 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 has 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.

[0153] The lens unit 11401 is an optical system provided at the connection portion 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 enters the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses including a zoom lens and a focus lens.

[0154] The imaging unit 11402 may include one imaging element (a so-called single-chip type) or multiple imaging elements (a so-called multi-chip type). When the imaging unit 11402 is configured as a multi-chip type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining these signals. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to 3D (dimensional) display. The 3D display allows the surgeon 11131 to more accurately grasp the depth of the biological tissue at the surgical site. Note that when the imaging unit 11402 is configured as a multi-chip type, multiple lens units 11401 may be provided corresponding to each imaging element.

[0155] Furthermore, 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.

[0156] The driving 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 the control of the camera head control unit 11405. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted appropriately.

[0157] The communication unit 11404 is configured by a communication device for transmitting and receiving various types of information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 to the CCU 11201 via the transmission cable 11400 as RAW data.

[0158] Furthermore, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201 and supplies the control signal to the camera head control unit 11405. The control signal includes information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value at the time of imaging, and / or information specifying the magnification and focus of the captured image.

[0159] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by the user, or 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 a so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

[0160] The camera head control unit 11405 controls the driving of the camera head 11102 based on a control signal received from the CCU 11201 via the communication unit 11404 .

[0161] The communication unit 11411 is configured by a communication device for transmitting and receiving various information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

[0162] Furthermore, the communication unit 11411 transmits to the camera head 11102 a control signal for controlling the driving of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.

[0163] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0164] The control unit 11413 performs various controls related to the imaging of the surgical site, etc. by the endoscope 11100 and the display of the captured image obtained by imaging the surgical site, etc. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

[0165] Furthermore, the control unit 11413 displays the captured image showing the surgical site, etc., on the display device 11202 based on the image signal subjected to 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 technologies. For example, the control unit 11413 can recognize surgical tools such as forceps, specific biological parts, bleeding, mist generated when using the energy treatment tool 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When displaying the captured image on the display device 11202, the control unit 11413 may use the recognition results to superimpose various surgical support information on the image of the surgical site. 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.

[0166] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for electrical signal communication, an optical fiber for optical communication, or a composite cable of these.

[0167] In the illustrated example, communication is performed wired using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

[0168] The above describes an example of an endoscopic surgery system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to, for example, the endoscope 11100, the camera head 11102, and other components of the above-described configuration. For example, the light detection device 1 shown in FIG. 1 can be applied to the image capture unit 10402. Applying the technology according to the present disclosure to the image capture unit 10402 can suppress false light detection and thereby reduce the occurrence of white spots in images of the surgical site, allowing the surgeon to reliably confirm the surgical site.

[0169] Although an endoscopic surgery system has been described as an example here, the technology disclosed herein may also be applied to other systems, such as a microsurgery system.

[0170] 7. Application Examples to Mobile Bodies The technology according to the present disclosure (the present technology) may be realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0171] FIG. 53 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology of the present disclosure can be applied.

[0172] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 53, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (Interface) 12053.

[0173] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0174] The body system control unit 12020 controls the operation of various devices equipped in 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 device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0175] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0176] The imaging unit 12031 is an optical 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.

[0177] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. 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 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0178] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle 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 the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0179] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0180] Furthermore, 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 outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0181] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying information to vehicle occupants or the outside of the vehicle. In the example of Fig. 53, the output devices are exemplified by 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 on-board display and a head-up display.

[0182] FIG. 54 is a diagram showing an example of the installation position of the imaging unit 12031.

[0183] In FIG. 54, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0184] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 provided on the top of the windshield inside the vehicle cabin is mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0185] 54 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0186] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0187] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which runs autonomously without relying on driver operation.

[0188] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes 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 a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0189] At least one of the image capturing 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 a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0190] 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, for example, the image capture unit 12031 among the above-described configurations. Specifically, for example, the photodetector 1 shown in FIG. 1 can be applied to the image capture unit 12031. By applying the technology according to the present disclosure to the image capture unit 12031, it is possible to obtain a captured image that is easier to see and in which the occurrence of white spots is suppressed, thereby reducing driver fatigue.

[0191] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0192] The present technology can also be configured as follows: (1) A photodetector comprising: a semiconductor layer having a photodiode provided therein; a floating diffusion provided inside one surface side of the semiconductor layer; a vertical gate extending from the one surface side toward the inside of the semiconductor layer; and a semiconductor region formed of a semiconductor of an opposite conductivity type to that of the photodiode and covering side and bottom surfaces of the vertical gate via a gate insulating film, wherein the semiconductor region has a width in a direction perpendicular to a plane equivalent to a plane with a 110 crystal orientation in a plan view that is smaller than the width in a direction perpendicular to a plane equivalent to a plane with a 100 crystal orientation in a plan view. (2) The photodetector according to (1), wherein the semiconductor region has a surface facing a charge transfer path from the photodiode to the floating diffusion that is equivalent to the plane with a 110 crystal orientation in a plan view. (3) The photodetector according to (1) or (2), comprising a pair of the vertical gates, wherein the floating diffusion is provided on an imaginary line passing between the pair of vertical gates in a plan view, and the semiconductor region has a surface covering opposing side surfaces of the pair of vertical gates that is equivalent to a plane having a crystal orientation of 110 in the plan view. (4) The photodetector comprises: a semiconductor layer having a photodiode provided therein, a floating diffusion provided inside one surface side of the semiconductor layer, a vertical gate extending from the one surface side toward the inside of the semiconductor layer, and a semiconductor region formed of a semiconductor of an opposite conductivity type to that of the photodiode and covering side surfaces and a bottom surface of the vertical gate via a gate insulating film, wherein a concentration of impurities of the opposite conductivity type in the semiconductor region is higher in a first region facing the bottom surface of the vertical gate than in a second region covering the side surfaces of the vertical gate and the first region. (5) The photodetector according to (4), wherein the first region has a width smaller than that of a structure including the vertical gate and the second region of the semiconductor region.(6) The photodetector according to (5), wherein the second region has a crystal defect between an interface with the semiconductor layer in a portion covering a side surface of the first region and an interface with the first region. (7) The photodetector according to (5), wherein the second region has a gap between an interface with the semiconductor layer in a portion covering a side surface of the first region and an interface with the first region. (8) The photodetector according to (5), wherein the gate insulating film has a first portion covering a side surface of the vertical gate, a second portion covering a bottom surface of the vertical gate, and a third portion extending from the first portion to surround a side surface of the first region in the semiconductor region.

[0193] 1, 1A to 1F, 3, 3A to 3E Photodetector device 11, 30 Semiconductor layer 22, 31 VG 12, 52 PD 13, 51 FD 14A to 14G Gate 23, 32 Gate insulating film 24 SW 25, 33 Semiconductor region 26 Silicon oxide film 27 Silicon nitride film 34 First region 35 Second region 36 Void 37 Crystal defect 41 First portion 42 Second portion 43 Third portion 17, 47 Gate contact 10, 50 Pixel isolation region 53 Fixed charge film

Claims

1. A photodetector comprising: a semiconductor layer having a photodiode therein; a floating diffusion provided inside one surface side of the semiconductor layer; a vertical gate extending from the one surface side toward the inside of the semiconductor layer; and a semiconductor region formed of a semiconductor of an opposite conductivity type to that of the photodiode and covering side and bottom surfaces of the vertical gate via a gate insulating film, wherein the width of the semiconductor region in a direction perpendicular to a plane equivalent to a plane with a 110 crystal orientation in a plan view is smaller than the width of the semiconductor region in a direction perpendicular to a plane equivalent to a 100 crystal orientation in a plan view.

2. The photodetector according to claim 1, wherein the semiconductor region has a surface facing a charge transfer path from the photodiode to the floating diffusion that is equivalent to a surface having a crystal orientation of 110 in the planar view.

3. The photodetector according to claim 1, comprising a pair of said vertical gates, said floating diffusion being provided on an imaginary line passing between said pair of said vertical gates in a planar view, and said semiconductor region having surfaces covering opposing side surfaces of said pair of said vertical gates that are equivalent to a surface having a crystal orientation of 110 in said planar view.

4. A photodetection device comprising: a semiconductor layer having a photodiode therein; a floating diffusion provided inside one surface side of the semiconductor layer; a vertical gate extending from the one surface side toward the inside of the semiconductor layer; and a semiconductor region formed of a semiconductor of an opposite conductivity type to that of the photodiode and covering side and bottom surfaces of the vertical gate via a gate insulating film, wherein a concentration of impurities of the opposite conductivity type in a first region facing the bottom surface of the vertical gate is higher than a concentration of impurities of the opposite conductivity type in a second region covering the side surfaces of the vertical gate and the first region.

5. The photodetector device of claim 4, wherein the first region has a width smaller than a structure including the vertical gate and the second region of the semiconductor region.

6. The photodetector device according to claim 5, wherein the second region has crystal defects between the interface with the semiconductor layer in the portion covering the side surface of the first region and the interface with the first region.

7. The photodetector according to claim 5, wherein the second region has a gap between the interface with the semiconductor layer in the portion covering the side surface of the first region and the interface with the first region.

8. The photodetector device according to claim 5, wherein the gate insulating film has a first portion covering a side surface of the vertical gate, a second portion covering a bottom surface of the vertical gate, and a third portion extending from the first portion so as to surround a side surface of the first region in the semiconductor region.

Images