Solid-state imaging device

Abstract

A solid-state imaging device 1A comprises a potential gradient formation unit 20A. The potential gradient formation unit 20A forms, on a photoelectric conversion unit 10A, a potential gradient in which a potential gradually changes from one end 201 to the other end 202 in a second direction D2. The potential gradient formation unit 20A has a plurality of resistive gate parts 21 and a plurality of ventilation parts 22. The plurality of resistive gate parts 21 respectively cover a plurality of pixel regions 11. The plurality of ventilation parts 22 are respectively provided on a plurality of pixel separation regions 12. The plurality of ventilation parts 22 each have an elongated shape in which the length thereof along the second direction D2 is greater than the width thereof along a first direction D1. The average value, in the second direction D2, of the width W4 of each ventilation part 22 is smaller than the average value, in the second direction D2, of the width W3 along the first direction D1 of a portion of each resistive gate part 21 which is sandwiched between the plurality of ventilation parts 22.

Description

Solid-state imaging device

[0001] This disclosure relates to a solid-state imaging device. This application claims priority based on Japanese Application No. 2024-160146 filed on September 17, 2024, and incorporates all the descriptions set forth in the said Japanese application.

[0002] Patent Document 1 discloses a solid-state imaging device. This solid-state imaging device includes a plurality of photoelectric conversion units. Each photoelectric conversion unit has a photosensitive region and a potential gradient formation region. The photosensitive region generates charges in response to light incidence. The planar shape of the photosensitive region forms a substantially rectangular shape formed by two long sides and two short sides. The potential gradient formation region forms a potential gradient in the photosensitive region. The potential gradient gradually increases along a first direction from one short side of the planar shape of the photosensitive region toward the other short side. The plurality of photoelectric conversion units are arranged side by side in a second direction intersecting the first direction.

[0003] Japanese Patent Application Laid-Open No. 2009-231768

[0004] In a solid-state imaging device such as a CCD, for example, a resistive gate may be used. A resistive gate is an electrode provided on a photoelectric conversion region and having a certain resistivity. By applying a potential difference to both ends in the charge movement direction, a resistive gate forms a potential gradient, thereby forming a potential gradient within the photoelectric conversion region. Since the potential gradient promotes the movement of charges, the charges remaining in the photoelectric conversion region are reduced and the image quality is improved.

[0005] On the other hand, an insulating film is formed on the photoelectric conversion region, but crystal defects are likely to occur on the surface of the photoelectric conversion region. The surface of the photoelectric conversion region is often the interface with the insulating film. It is effective to perform a termination process on the dangling bonds generated in such crystal defects. For example, the dangling bonds of Si in the crystal defects occurring at the interface between silicon (Si) and silicon oxide (SiO ２ ) are terminated with hydrogen.

[0006] Solid-state imaging devices (Solid State Imaging Systems) use materials that do not allow termination gas to pass through, such as polysilicon, for their electrodes. In conventional Solid State Imaging Systems (non-resistive gate type), termination gas enters through the gaps between transfer electrodes arranged in multiple stages and reaches the surface of the photoelectric conversion region. However, in resistive gate type Solid State Imaging Systems, a single resistive gate covers the entire surface of the photoelectric conversion region, so the resistive gate obstructs the entry of termination gas, resulting in unterminated areas on the surface of the photoelectric conversion region. As a result, charge transfer characteristics deteriorate and dark current increases. In recent years, there has been a demand for larger photoelectric conversion regions, and as the area of ​​the photoelectric conversion region increases, unterminated areas are more likely to occur, making this problem more pronounced.

[0007] The present disclosure aims to provide a solid-state imaging device that can eliminate or reduce the portion of the surface of the photoelectric conversion region that is not terminated.

[0008] [1] The solid-state imaging apparatus according to the present disclosure comprises a photoelectric conversion unit and a potential gradient forming unit. The photoelectric conversion unit has a plurality of pixel regions that generate charge in response to incident light and a plurality of pixel separation regions that separate the plurality of pixel regions from each other. The plurality of pixel regions and the plurality of pixel separation regions are arranged alternately along a first direction. The potential gradient forming unit is provided on the photoelectric conversion unit. The potential gradient forming unit forms a potential gradient on the photoelectric conversion unit in which the potential gradually changes from one end to the other in a second direction intersecting the first direction. The potential gradient forming unit has a plurality of resistive gate units and a plurality of ventilation units. The plurality of resistive gate units each cover a plurality of pixel regions. The plurality of ventilation units each have a length along the second direction that is greater than the width along the first direction. The average value of the width of each ventilation section in the second direction is smaller than the average value of the width of the portion of each resistive gate section sandwiched between multiple ventilation sections in the second direction, along the first direction.

[0009] In the solid-state imaging device described in [1] above, the potential gradient forming section has a plurality of ventilation sections. Since the plurality of ventilation sections are provided on each of the plurality of pixel isolation regions, they are arranged alternately with the plurality of resistive gate sections that each cover the plurality of pixel regions. When manufacturing the solid-state imaging device, gas for termination treatment enters from each ventilation section and spreads under each resistive gate section, thereby terminating the surface of each pixel region. This eliminates or reduces the portion of each pixel region that is not terminated, thereby suppressing a decrease in charge transfer characteristics and an increase in dark current. In addition, since the average value of the width of each ventilation section in the second direction is smaller than the average value of the width of the portion of each resistive gate section sandwiched between the plurality of ventilation sections in the second direction along the first direction, a sufficient width can be secured for each resistive gate section, thereby suppressing a decrease in charge transfer characteristics.

[0010] [2] In the solid-state imaging apparatus described in [1] above, the width of each pixel region along the first direction, the width of each pixel separation region along the first direction, the width of each resistive gate portion, and the width of each ventilation portion may be substantially constant from one end to the other. In this case, the variation in the rate of change of the potential gradient in the second direction can be reduced, and good charge transfer characteristics can be maintained.

[0011] [3] In the solid-state imaging apparatus described in [1] above, the width of each pixel region along the first direction and the width of each resistive gate portion may gradually increase from one end to the other. The width of each pixel separation region along the first direction and the width of each ventilation portion may gradually decrease from one end to the other. In this case, the width of the ventilation portion widens near the start of charge transfer, which can promote the entry of gas for termination processing. In addition, the width of the resistive gate portion widens near the end of charge transfer, which can promote charge transfer. Furthermore, the potential gradient effect due to the change in the width of the pixel region is added to the potential gradient effect due to the potential gradient. Therefore, the potential gradient becomes steeper, which can further promote charge transfer.

[0012] [4] In the solid-state imaging apparatus described in [1] to [3] above, each ventilation section may be a gap formed between a plurality of resistive gate sections. In this case, each ventilation section through which the gas for termination processing passes can be easily formed.

[0013] [5] In the solid-state imaging apparatus described in [1] to [4] above, each ventilation section may be provided continuously from one end to the other of the potential gradient forming section. Multiple resistive gate sections may be separated from each other by multiple ventilation sections. In this case, the bias in the potential distribution within each resistive gate section can be reduced, thereby suppressing a decrease in charge transfer characteristics.

[0014] [6] In the solid-state imaging apparatus described in [1] to [5] above, the average value of the width of each ventilation section in the second direction may be smaller than the width of each pixel separation region along the first direction. In this case, the width of each resistive gate section along the first direction can be made larger than the width of each pixel region along the first direction, and a potential gradient can be formed over the entire pixel region. Therefore, a decrease in charge transfer characteristics can be suppressed.

[0015] [7] The solid-state imaging apparatus according to the present disclosure comprises a photoelectric conversion unit and a potential gradient forming unit. The photoelectric conversion unit has a plurality of pixel regions that generate charge in response to incident light and a plurality of pixel separation regions that separate the plurality of pixel regions from each other. The plurality of pixel regions and the plurality of pixel separation regions are arranged alternately along a first direction. The potential gradient forming unit is provided on the photoelectric conversion unit. The potential gradient forming unit forms a potential gradient on the photoelectric conversion unit in which the potential gradually changes from one end to the other in a second direction intersecting the first direction. The potential gradient forming unit has a first resistive gate section, a second resistive gate section, a ventilation section, a first wiring, a second wiring, and a third wiring. The first resistive gate section covers a part of each pixel region. The second resistive gate section is arranged side by side with the first resistive gate section in the second direction and covers at least a part of the remainder of each pixel region. The ventilation section is provided between the first resistive gate section and the second resistive gate section. The first wiring applies a first voltage to the first end of the first resistive gate section that is farther from the second resistive gate section. The second wiring applies a second voltage, different from the first voltage, to the second end of the second resistive gate section that is farther from the first resistive gate section. The third wiring applies a third voltage, having a magnitude between the first voltage and the second voltage, to the second end of the first resistive gate section that is closer to the second resistive gate section, and to the first end of the second resistive gate section that is closer to the first resistive gate section.

[0016] [8] The solid-state imaging apparatus according to the present disclosure comprises a photoelectric conversion unit and a potential gradient forming unit. The photoelectric conversion unit has a plurality of pixel regions that generate charge in response to incident light and a plurality of pixel separation regions that separate the plurality of pixel regions from each other. The plurality of pixel regions and the plurality of pixel separation regions are arranged alternately along a first direction. The potential gradient forming unit is provided on the photoelectric conversion unit. The potential gradient forming unit forms a potential gradient on the photoelectric conversion unit in which the potential gradually changes from one end to the other in a second direction intersecting the first direction. The potential gradient forming unit has a first resistive gate section, a second resistive gate section, a ventilation section, a first wiring section, a plurality of connection sections, and a second wiring section. The first resistive gate section covers a part of each pixel region. The second resistive gate section is arranged side by side with the first resistive gate section in the second direction and covers at least a part of the remainder of each pixel region. The ventilation section is provided between the first resistive gate section and the second resistive gate section. The first wiring applies a first voltage to the first end of the first resistive gate section that is farther from the second resistive gate section. Multiple connection points electrically connect the second end of the first resistive gate section that is closer to the second resistive gate section to the first end of the second resistive gate section that is closer to the first resistive gate section. The second wiring applies a second voltage, different from the first voltage, to the second end of the second resistive gate section that is farther from the first resistive gate section.

[0017] In the solid-state imaging devices described in [7] and [8] above, the potential gradient forming unit has a ventilation section provided between the first resistive gate unit and the second resistive gate unit. When manufacturing the solid-state imaging device, gas for termination processing enters from the ventilation section and spreads from the ventilation section to below the first resistive gate unit and the second resistive gate unit, thereby terminating the surface of each pixel region. This eliminates or reduces the portion of each pixel region that is not terminated, thereby suppressing a decrease in charge transfer characteristics and an increase in dark current. In addition, by providing a ventilation section between the first resistive gate unit and the second resistive gate unit, which are arranged side by side in the second direction, sufficient width can be secured for the first resistive gate unit and the second resistive gate unit, thereby suppressing a decrease in charge transfer characteristics. Furthermore, a potential gradient continuous from the first resistive gate unit to the second resistive gate unit can be formed, creating a potential gradient extending from one end to the other within each pixel region.

[0018] [9] In the solid-state imaging device described in [8] above, each of the multiple connection parts may block each of the multiple parts of the ventilation section. In this case, the first resistive gate section and the second resistive gate section can be efficiently connected by the shortest conductive path.

[0019]

[10] In the solid-state imaging apparatus described in [8] or [9] above, each of the multiple connection parts may be arranged on each of the multiple pixel separation regions. In this case, when light is incident on each pixel region through the potential gradient forming part, the connection members can be prevented from obstructing the incidence of light to each pixel region. In addition, the extent to which the connection parts obstruct the entry of the gas for termination processing onto the surface of each pixel region can be reduced.

[0020]

[11] In the solid-state imaging apparatus described in [8] or [9] above, each of the plurality of connection portions may be arranged on each of the plurality of pixel regions. In this case, the occurrence of bias in the potential distribution in the region around the ventilation portion of the first resistive gate portion and the second resistive gate portion can be suppressed, and the deterioration of charge transfer characteristics can be suppressed.

[0021]

[12] In the solid-state imaging apparatus described in [8] to

[11] above, the potential gradient forming section may further include a metal flat film section that connects a plurality of connection sections to each other. Multiple openings are formed in the flat film section, and the flat film section may cover the entire surface of a plurality of pixel regions. In this case, light incident from the back surface of the solid-state imaging apparatus that is not absorbed by the pixel regions but passes through the pixel regions, in particular long-wavelength light that easily penetrates Si, can be reflected by the flat film section and absorbed by the pixel regions. This makes it possible to increase the photoelectric conversion efficiency. In addition, because multiple openings are formed in the flat film section, gas for termination processing can be efficiently sent to the ventilation section through the multiple openings.

[0022]

[13] In the solid-state imaging apparatus described in [7] to

[12] above, the first resistive gate section, the second resistive gate section, and the ventilation section may be continuously provided over at least two pixel regions among the plurality of pixel regions. In this case, the potential distribution can be made more uniform between at least two pixel regions, so that a decrease in charge transfer characteristics can be suppressed.

[0023]

[14] In the solid-state imaging apparatus described in [7] to

[13] above, one of the first resistive gate portion and the second resistive gate portion may include a base portion and an extended portion. The base portion is provided on the same plane as the other resistive gate portion of the first resistive gate portion and the second resistive gate portion. The extended portion extends from the base portion and aligns with the other resistive gate portion in a third direction that intersects both the first and second directions. The ventilation portion may be continuous from the gap between the base portion and the other resistive gate portion to the gap between the extended portion and the other resistive gate portion. In this case, a ventilation portion can be provided between the first resistive gate portion and the second resistive gate portion, while also forming an uninterrupted potential gradient at the boundary between the first resistive gate portion and the second resistive gate portion. Therefore, a decrease in charge transfer characteristics due to the provision of the ventilation portion can be suppressed.

[0024]

[15] In the solid-state imaging apparatus described in [7] above, one of the first resistive gate portion and the second resistive gate portion may include a base portion and an extension portion. The base portion is provided on the same plane as the other resistive gate portion of the first resistive gate portion and the second resistive gate portion. The extension portion extends from the base portion and aligns with the other resistive gate portion in a third direction that intersects both the first and second directions. The ventilation portion may be continuous from the gap between the base portion and the other resistive gate portion to the gap between the extension portion and the other resistive gate portion. The third wiring may be connected to the extension portion and the portion of the other resistive gate portion that aligns with the extension portion in the third direction. In this case, a ventilation portion can be provided between the first resistive gate portion and the second resistive gate portion, while forming an uninterrupted potential gradient at the boundary portion between the first resistive gate portion and the second resistive gate portion. Therefore, the deterioration of charge transfer characteristics due to the provision of ventilation can be suppressed.

[0025] According to this disclosure, it is possible to provide a solid-state imaging device that can eliminate or reduce the portion on the surface of the photoelectric conversion region that is not terminated.

[0026] Figure 1 is a diagram showing the configuration of a solid-state imaging device according to the first embodiment. Figure 2 is a diagram illustrating the change in potential energy in each pixel constituting the solid-state imaging device. Figure 3 is a plan view showing a conventional resistive gate. Figure 4 is a diagram schematically showing the magnitude of the dark current and the distribution of the amount of unreadable charge in the photoelectric conversion region. Figure 5 is a diagram schematically showing the current flow from the low potential end to the high potential end. Figure 6 is a diagram showing the configuration of a solid-state imaging device according to the first modified example. Figure 7 is a diagram showing the configuration of a solid-state imaging device according to the second embodiment. Figure 8 is a diagram showing the configuration of a solid-state imaging device according to the second modified example. Figure 9 is a diagram showing the configuration of a solid-state imaging device according to the third modified example. Figure 10 is a diagram showing the configuration of a solid-state imaging device according to the fourth modified example.

[0027] Specific examples of the solid-state imaging apparatus of this disclosure will be described below with reference to the drawings. The present invention is not limited to these examples, but is intended to be limited to those shown in the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included. In the following description, the same elements in the description of the drawings are denoted by the same reference numerals, and redundant descriptions are omitted.

[0028] [First Embodiment] Figure 1 is a diagram showing the configuration of a solid-state imaging device 1A according to the first embodiment of the present disclosure. Part 1(a) of Figure 1 shows a plan view of the solid-state imaging device 1A. Part 1(b) of Figure 1 schematically shows a cross section of the solid-state imaging device 1A perpendicular to the second direction D2. As shown in Figure 1, the solid-state imaging device 1A of this embodiment is a linear image sensor in which a plurality of pixel regions 11 are arranged in one dimension along the first direction D1. The solid-state imaging device 1A includes a photoelectric conversion unit 10A (photoelectric conversion region) and a potential gradient forming unit 20A. The photoelectric conversion unit 10A has a plurality of pixel regions 11, a plurality of pixel separation regions 12, a semiconductor region 13 and an insulating region 14.

[0029] Each pixel region 11 generates an electric charge in response to incident light. That is, each pixel region 11 generates an amount of electric charge corresponding to the intensity of the light incident on it. The solid-state imaging device 1A further includes a horizontal register (not shown). The horizontal register has a plurality of charge holding units, each electrically connected to a plurality of pixel regions 11. Each charge holding unit receives an electric charge from the corresponding pixel region 11 and holds that electric charge. The horizontal register sequentially transfers the electric charge held by the plurality of charge holding units and outputs it. Each pixel region 11 is made of a semiconductor of a first conductivity type (e.g., n-type). Each pixel region 11 is made of, for example, n-type Si. Each pixel region 11 is formed, for example, by ion implanting a dopant of the first conductivity type into a semiconductor substrate.

[0030] Multiple pixel regions 11 and multiple pixel isolation regions 12 are arranged alternately along a first direction D1. The multiple pixel isolation regions 12 separate the multiple pixel regions 11 from each other. Each pixel isolation region 12 is made of a semiconductor of a second conductivity type (e.g., p-type) different from that of each pixel region 11. The impurity concentration of each pixel isolation region 12 is higher than the impurity concentration of the semiconductor region 13, which will be described later. Each pixel isolation region 12 is made of, for example, p-type Si. Each pixel isolation region 12 is formed, for example, by ion implantation of a dopant of the second conductivity type into a semiconductor substrate. In the illustrated example, each pixel isolation region 12 is in contact with an adjacent pixel region 11.

[0031] Each pixel region 11 and each pixel separation region 12 have a rectangular shape with a second direction D2 that intersects (for example, is orthogonal to) the first direction D1 as its longitudinal direction. The width W1 of each pixel region 11 along the first direction D1 and the width W2 of each pixel separation region 12 along the first direction D1 are substantially constant from one end to the other in the second direction D2.

[0032] The semiconductor region 13 extends along a first direction D1 and is in contact with one surface of a plurality of pixel regions 11. The semiconductor region 13 is composed of a semiconductor of a second conductivity type (e.g., p-type). The semiconductor region 13 forms a pn junction with the plurality of pixel regions 11. The semiconductor region 13 is made of, for example, p-type Si. The semiconductor region 13 is, for example, part of a semiconductor substrate of a second conductivity type. The semiconductor region 13 is connected to an electrode (not shown) and is defined to a reference potential through the electrode.

[0033] The insulating region 14 extends along the first direction D1 and is provided over a plurality of pixel regions 11 and a plurality of pixel isolation regions 12. The insulating region 14 is in contact with the surfaces of the plurality of pixel regions 11 and the plurality of pixel isolation regions 12 that are opposite to the surfaces in contact with the semiconductor region 13. The thickness of the portion of the insulating region 14 provided on each pixel region 11 is thinner than the thickness of the portion of the insulating region 14 provided on each pixel isolation region 12. The insulating region 14 is made of silicon oxide (SiO₂) produced by LOCOS (LOCal Oxidation of Silicon), for example. ２ ) mainly includes.

[0034] The potential gradient forming unit 20A is provided on the photoelectric conversion unit 10A. The potential gradient forming unit 20A forms a potential gradient on the photoelectric conversion unit 10A in which the potential gradually increases from one end 201 (low potential end) to the other end 202 (high potential end) in the second direction D2. The potential gradient forming unit 20A in this embodiment has a plurality of resistive gate units 21 and a plurality of ventilation units 22. In Figure 1, the plurality of resistive gate units 21 are shown by halftones.

[0035] Multiple resistive gate portions 21 each cover multiple pixel regions 11. That is, each resistive gate portion 21 is provided on a corresponding pixel region 11 and faces the pixel region 11 across an insulating region 14. Each resistive gate portion 21 does not necessarily have to cover the entire surface of each pixel region 11, and there may be parts of each pixel region 11 that are not covered by each resistive gate portion 21. Each resistive gate portion 21 is made of a conductive resistive material such as polysilicon. Each resistive gate portion 21 may be made of a resistive material that is more transparent than polysilicon, such as ITO (Indium-Tin Oxide) or a thin layer of SiCr. In that case, light will pass through the potential gradient forming portion 20A more easily than when the resistive gate portion 21 is made of polysilicon. Therefore, it becomes possible to detect light with higher sensitivity in multiple pixel regions 11. Each resistive gate portion 21 extends along the second direction D2 over the region on the pixel region 11. The resistive gate portion 21 of this embodiment has a rectangular shape with the second direction D2 as the longitudinal direction. The width W3 of each resistive gate portion 21 along the first direction D1 is substantially constant from one end 201 to the other end 202. The width W3 of each resistive gate portion 21 is greater than the width W1 of each pixel region 11.

[0036] A first wiring (not shown) is connected to one end 201 (low potential end) of the resistive gate portion 21 in the second direction D2. The potential at the low potential end is defined by a first voltage applied by the first wiring. A second wiring (not shown) is connected to the other end 202 (high potential end) of the resistive gate portion 21 in the second direction D2. The potential at the high potential end is defined by a second voltage applied by the second wiring. The second voltage is higher than the first voltage. As a result, a potential gradient is formed between the low potential end and the high potential end of the resistive gate portion 21.

[0037] Part 2(a) of Figure 2 schematically shows a cross-section along the longitudinal direction of each pixel 2 constituting the solid-state imaging device 1A. As shown in Part 2(a) of Figure 2, each pixel 2 further has semiconductor regions 15 to 17 in addition to the pixel region 11 and semiconductor region 13 described above. Each pixel 2 further has a holding electrode 28a and transfer electrodes 28b and 28c in addition to the resistive gate portion 21 described above.

[0038] Semiconductor region 15 is a region of the second conductivity type (e.g., p-type). The impurity concentration in semiconductor region 15 is higher than that of semiconductor region 13. Semiconductor region 16 is a region of the first conductivity type (e.g., n-type). The impurity concentration in semiconductor region 16 is lower than that of pixel region 11. Semiconductor region 17 is a region of the first conductivity type (e.g., n-type). The impurity concentration in semiconductor region 17 is higher than that of semiconductor region 16 and is equal to, for example, the impurity concentration of pixel region 11. Semiconductor regions 15 to 17 are provided on semiconductor region 13 and are arranged in the order of semiconductor region 15, pixel region 11, semiconductor region 16, and semiconductor region 17 along the second direction D2. Light incident on pixel 2 is converted into charge at the pn junction surface at the boundary between pixel region 11 and semiconductor region 13.

[0039] The retaining electrode 28a is provided on the pixel region 11 and faces the pixel region 11 across the insulating region 14 (see Figure 1). On the pixel region 11, the retaining electrode 28a is aligned with the resistive gate portion 21 along the second direction D2. That is, the retaining electrode 28a is positioned near the end of the pixel region 11 in the charge transfer direction. The transfer electrode 28b is provided on the semiconductor region 16 and faces the semiconductor region 16 across the insulating region 14. The transfer electrode 28c is provided on the semiconductor region 17 and faces the semiconductor region 17 across the insulating region 14. In one example, the transfer electrode 28c is set to the same potential as the transfer electrode 28b.

[0040] Part 2(b) of Figure 2 shows the change in potential energy along the second direction D2 in each pixel 2. As shown in Part 2(b) of Figure 2, the potential energy E1 of the semiconductor region 15 is the lowest, and the potential energies E2 and E3 of the pixel region 11 are higher than that. The potential energy E3 of the region of the pixel region 11 facing the holding electrode 28a is higher than the potential energy E2 of the region of the pixel region 11 facing the resistive gate portion 21. The potential energy E5 of the semiconductor region 17 is higher than the potential energy E4 of the semiconductor region 16.

[0041] As described above, a first voltage is applied to one end 201 of the resistive gate portion 21 from the first wiring 31. A second voltage, higher than the first voltage, is applied to the other end 202 of the resistive gate portion 21 from the second wiring 32. The potential gradient between the one end 201 and the other end 202 applies an electric field with a gradient in strength to the pixel region 11. This creates a potential gradient in the potential energy E2 of the pixel region 11 that promotes charge movement. That is, the potential energy E2 gradually increases as you move from the one end 201 towards the other end 202.

[0042] During a certain period while imaging, by controlling the potential of the transfer electrode 28b, the potential energy E4 is set lower than the potential energy E3. At this time, the region of the potential energy E3 acts as a potential well for holding the charge Q. In addition, the potential gradient of the potential energy E2 promotes the movement of the charge Q into the potential well within the pixel region 11. The moving direction of the charge Q at this time coincides with the second direction D2. Then, during a subsequent period, by controlling the potential of the transfer electrode 28b, the potential energy E4 is set higher than the potential energy E3. As a result, the charge Q held in the potential well is transferred to the charge holding portion of the horizontal register through the semiconductor region 16 and the semiconductor region 17.

[0043] Referring to FIG. 1 again, the plurality of resistive gate portions 21 and the plurality of ventilation portions 22 are alternately arranged along the first direction D1. The plurality of ventilation portions 22 are respectively provided on the plurality of pixel separation regions 12. Each ventilation portion 22 is, for example, a gap formed between the plurality of resistive gate portions 21. Each ventilation portion 22 is continuously provided from one end 201 to the other end 202 of the potential gradient forming portion 20A. The plurality of resistive gate portions 21 are separated from each other by the plurality of ventilation portions 22.

[0044] Each ventilation portion 22 allows a gas to pass through for terminating the surface of each pixel region 11, that is, the interface between each pixel region 11 and the insulating region 14, when manufacturing the solid-state imaging device 1A. The gas enters the gap between each resistive gate portion 21 and the insulating region 14 through each ventilation portion 22. The gas is, for example, hydrogen. Hydrogen reacts with Si contained in the pixel region 11 and SiO contained in the insulating region 14. ２It bonds to the dangling bonds of Si in the crystal defects generated at the interface with, and terminates the dangling bonds. In order to allow the gas to spread throughout all parts within each pixel region 11, as viewed from the third direction D3 that intersects both the first direction D1 and the second direction D2, all parts within each pixel region 11 are within a range not exceeding the gas penetration distance from the ventilation part 22 or the edge of any resistive gate part 21. Each ventilation part 22 only needs to be able to allow the gas to pass through during the surface termination process of each pixel region 11, and may then be blocked by a protective film or the like.

[0045] The plurality of ventilation parts 22 have an elongated shape with a length along the second direction D2 greater than the width W4 along the first direction D1. The ventilation part 22 of the present embodiment has a rectangular shape with the second direction D2 as the longitudinal direction. That is, the width W4 of each ventilation part 22 is substantially constant from one end 201 to the other end 202. The width W4 of each ventilation part 22 is smaller than the width W3 of each resistive gate part 21. More precisely, the average value of the width W4 of each ventilation part 22 in the second direction D2 is smaller than the average value of the width W3 of the part sandwiched between the plurality of ventilation parts 22 of each resistive gate part 21 in the second direction D2. The average value of the width W4 of each ventilation part 22 in the second direction D2 is smaller than the width W2 along the first direction D1 of each pixel isolation region 12.

[0046] The effects obtained by the solid-state imaging device 1A of this embodiment, as described above, will now be explained along with the problems of conventional solid-state imaging devices. When manufacturing conventional solid-state imaging devices, termination treatment is performed on the surface of the photoelectric conversion region using a gas such as hydrogen. At that time, since the photoelectric conversion region is already covered by electrodes, the gas such as hydrogen needs to reach the surface of the photoelectric conversion region while avoiding the electrodes. In a normal solid-state imaging device that is not of the resistive gate type, the gas can enter through the gaps between transfer electrodes arranged in multiple stages, so the gas can easily reach the entire surface of the photoelectric conversion region. However, in a conventional resistive gate type solid-state imaging device, a single resistive gate extends across multiple pixels so as to cover the entire photoelectric conversion region. Therefore, the resistive gate obstructs the entry of the gas. The gas can only enter from the edge of the resistive gate, resulting in the problem that termination treatment is not performed on the central part of the surface of the photoelectric conversion region that is far from the edge of the resistive gate.

[0047] Figure 3 is a plan view showing a conventional resistive gate 29. The resistive gate 29 covers multiple pixels, for example, in a first direction D1. Gas can enter regions where the distance d from the edge of the resistive gate 29 is less than or equal to a certain distance, but gas cannot enter regions where the distance d exceeds a certain distance. As a result, an un-terminating area 118 is created in the central part of the resistive gate 29 in a plan view. Consequently, in pixels overlapping with the un-terminating area 118, the dark current increases and the charge transfer characteristics deteriorate. Part 4(a) of Figure 4 schematically shows the distribution of the magnitude of the dark current in the photoelectric conversion region. In part 4(a) of Figure 4, the vertical axis shows the magnitude of the dark current, and the horizontal axis shows the pixel number. As shown in part 4(a) of Figure 4, the dark current is small in regions less than or equal to the gas penetration distance from both ends of the photoelectric conversion region, but the dark current becomes significantly larger in regions beyond the gas penetration distance from both ends of the photoelectric conversion region, i.e., in regions overlapping with the un-terminating area 118. Part 4(b) of Figure 4 schematically shows the distribution of unreadable charge in the photoelectric conversion region. In Part 4(b) of Figure 4, the vertical axis represents the unreadable charge, and the horizontal axis represents the pixel position. As shown in Part 4(b) of Figure 4, the unreadable charge is small in the region below the gas penetration distance from both ends of the photoelectric conversion region, but the unreadable charge becomes significantly larger in the region beyond the gas penetration distance from both ends of the photoelectric conversion region, i.e., the region overlapping with the un-terminating area 118.

[0048] It is conceivable to form an opening in the resistive gate 29 to allow gas to enter. However, simply forming an opening may cause the opening to obstruct the flow of current within the resistive gate 29, potentially leading to a bias in the potential distribution of the resistive gate 29. That is, as shown in part (a) of Figure 5, a normal resistive gate 29 has a uniform resistivity overall, and the flow of current J from the low potential end to the high potential end is uniform, resulting in little bias in the potential distribution. In contrast, as shown in part (b) of Figure 5, if an opening 291 is formed in the resistive gate 29 without considering the potential distribution, turbulence occurs in the flow of current J from the low potential end to the high potential end around the opening 291, causing a bias in the potential distribution of the resistive gate 29. As a result, the charge transfer characteristics deteriorate in some pixels.

[0049] To address the above issues, the solid-state imaging device 1A of this embodiment has a potential gradient forming section 20A provided on each of the multiple pixel separation regions 12, and has a plurality of elongated ventilation sections 22 whose length along the second direction D2 is greater than the width W4 along the first direction D1. When manufacturing the solid-state imaging device 1A, gas for termination processing enters from each ventilation section 22 and spreads under each resistive gate section 21, thereby terminating the surface of each pixel region 11. This eliminates or reduces the portion of each pixel region 11 that is not terminated (un-terminated area), thereby suppressing a decrease in charge transfer characteristics and an increase in dark current. In addition, in this embodiment, the average value of the width W4 of each ventilation section 22 in the second direction D2 is smaller than the average value of the width W3 along the first direction D1 in the second direction D2 of the portion of each resistive gate section 21 sandwiched between the plurality of ventilation sections 22. This ensures sufficient width for each resistive gate section 21. Therefore, the decrease in charge transfer characteristics due to the provision of the ventilation section 22 can be suppressed.

[0050] When each pixel region 11 mainly contains Si, the interface between each pixel region 11 and the insulating region 14 is of better quality compared to when each pixel region 11 mainly contains other semiconductor materials (e.g., compound semiconductors). Therefore, the effect of dangling bonds on charge transfer characteristics and dark current generation is significant, and hydrogen termination is considered highly important.

[0051] As in this embodiment, the width W1 of each pixel region 11 along the first direction D1, the width W2 of each pixel separation region 12 along the first direction D1, the width W3 of each resistive gate portion 21, and the width W4 of each ventilation portion 22 may be substantially constant from one end 201 to the other end 202. In this case, the variation in the rate of change of the potential gradient in the second direction D2 can be reduced, and good charge transfer characteristics can be maintained.

[0052] As in this embodiment, each ventilation section 22 may be a gap formed between a plurality of resistive gate sections 21. In this case, each ventilation section 22 through which the gas for termination processing passes can be easily formed.

[0053] As in this embodiment, each ventilation section 22 may be provided continuously from one end 201 to the other end 202 of the potential gradient forming section 20A. Furthermore, the multiple resistive gate sections 21 may be separated from each other by the multiple ventilation sections 22. In this case, the bias in the potential distribution within each resistive gate section 21 can be reduced, thereby suppressing a decrease in charge transfer characteristics.

[0054] As in this embodiment, the average value of the width W4 of each ventilation portion 22 in the second direction D2 may be smaller than the width W2 along the first direction D1 of each pixel separation region 12. In this case, the width W3 along the first direction D1 of each resistive gate portion 21 can be made larger than the width W1 along the first direction D1 of each pixel region 11. Therefore, the deterioration of charge transfer characteristics due to the provision of the ventilation portion 22 can be further suppressed.

[0055] [First Modified Example] Figure 6 shows the configuration of a solid-state imaging device 1B according to the first modified example of the present disclosure. Part 6(a) of Figure 6 shows a plan view of the solid-state imaging device 1B. Part 6(b) of Figure 6 schematically shows a cross-section of the solid-state imaging device 1B perpendicular to the second direction D2. The solid-state imaging device 1B of this modified example differs from the solid-state imaging device 1A of the first embodiment in the planar shapes of the pixel region, pixel separation region, resistive gate region and ventilation region, and is identical to the solid-state imaging device 1A of the first embodiment in other respects. The solid-state imaging device 1B of this modified example includes a photoelectric conversion unit 10B and a potential gradient forming unit 20B instead of the photoelectric conversion unit 10A and potential gradient forming unit 20A of the first embodiment.

[0056] In the photoelectric conversion unit 10B and potential gradient forming unit 20B of this modified example, the width W1 of each pixel region 11 along the first direction D1 and the width W3 of each resistive gate portion 21 along the first direction D1 gradually increase from one end 201 to the other end 202. In one example, each pixel region 11 and each resistive gate portion 21 of this modified example have a trapezoidal shape. The width W2 of each pixel separation region 12 along the first direction D1 and the width W4 of each ventilation portion 22 along the first direction D1 gradually decrease from one end 201 to the other end 202. In one example, each pixel separation region 12 and each ventilation portion 22 of this modified example have a trapezoidal shape. In one example, the amount of change in width W1 to W4 per unit length along the second direction D2 is constant from one end 201 to the other end 202.

[0057] In this modified example, the effects of the first embodiment can be obtained. In addition, in this modified example, the width W4 of the ventilation portion 22 is increased near the starting end of the charge transfer, which promotes the entry of gas for termination processing. In this modified example, one end 201 corresponds to the starting end. In addition, the width W3 of the resistive gate portion 21 is increased near the end of the charge transfer, which promotes charge transfer near the end where the amount of charge increases. In this modified example, the other end 202 corresponds to the end. In addition, the potential gradient effect due to the change in the width W1 of the pixel region 11 is added to the potential gradient effect due to the potential gradient. Therefore, the potential gradient becomes steeper, which further promotes charge transfer. In addition, since the spacing between the multiple resistive gate portions 21 is wider compared to the first embodiment, the risk of short-circuiting between adjacent resistive gate portions 21 can be reduced. However, when light is transmitted through the potential gradient forming portion and incident on the photoelectric conversion portion, the aperture ratio can be increased more in the first embodiment than in this modified example.

[0058] [Second Embodiment] Figure 7 is a diagram showing the configuration of a solid-state imaging device 1C according to the second embodiment of the present disclosure. Part 7(a) of Figure 7 shows a plan view of the solid-state imaging device 1C. Part 7(b) of Figure 7 schematically shows a cross section perpendicular to the second direction D2 of the solid-state imaging device 1C. Part 7(c) of Figure 7 schematically shows a cross section perpendicular to the first direction D1 of the potential gradient forming unit 20C provided in the solid-state imaging device 1C. The solid-state imaging device 1C of this modified embodiment differs from the solid-state imaging device 1A of the first embodiment in the configuration of the potential gradient forming unit, and is consistent with the solid-state imaging device 1A of the first embodiment in other respects. The solid-state imaging device 1C of this modified embodiment is equipped with a potential gradient forming unit 20C instead of the potential gradient forming unit 20A of the first embodiment.

[0059] The potential gradient forming section 20C is provided on the photoelectric conversion section 10A. The potential gradient forming section 20C forms a potential gradient on the photoelectric conversion section 10A in which the potential gradually increases from one end 201 to the other end 202 in the second direction D2. The potential gradient forming section 20C in this embodiment has a first resistive gate section 23, a second resistive gate section 24, and a ventilation section 25.

[0060] The first resistive gate portion 23 covers a portion of each pixel region 11. In the illustrated example, the first resistive gate portion 23 covers the lower potential half of each pixel region 11. The second resistive gate portion 24 is arranged alongside the first resistive gate portion 23 along the second direction D2. The second resistive gate portion 24 covers at least a portion of the remainder of each pixel region 11. In the illustrated example, the second resistive gate portion 24 covers the remainder of each pixel region 11, i.e., the higher potential half of each pixel region 11. The first resistive gate portion 23 and the second resistive gate portion 24 extend along the first direction D1 and are continuously provided over at least two of the multiple pixel regions 11 (over all of the pixel regions 11 in the illustrated example). The first resistive gate portion 23 and the second resistive gate portion 24 face the at least two pixel regions 11 across an insulating region 14. The first resistive gate portion 23 and the second resistive gate portion 24 are made of a conductive resistive material, such as polysilicon. The first resistive gate portion 23 and the second resistive gate portion 24 may also be made of a resistive material that is more transparent than polysilicon, such as ITO (Indium-Tin Oxide) or a thin layer of SiCr. In that case, light will pass through the potential gradient forming portion 20C more easily than when the first resistive gate portion 23 and the second resistive gate portion 24 are made of polysilicon. Therefore, it becomes possible to detect light with higher sensitivity in multiple pixel regions 11.

[0061] The second resistive gate portion 24 includes a base portion 241 and an extension portion 242. The base portion 241 is provided on the same plane as the first resistive gate portion 23. The extension portion 242 extends from the base portion 241 and aligns with the first resistive gate portion 23 in the third direction D3. In other words, as viewed from the third direction D3, the extension portion 242 of the second resistive gate portion 24 overlaps with the first resistive gate portion 23. The first resistive gate portion 23 may also include such a base portion and extension portion instead of the second resistive gate portion 24. In that case, the base portion of the first resistive gate portion 23 is provided on the same plane as the second resistive gate portion 24. The extension portion of the first resistive gate portion 23 extends from the base and aligns with the second resistive gate portion 24 in the third direction D3. Neither the extended portion 242 of the second resistive gate portion 24 nor the extended portion of the first resistive gate portion 23 is provided.

[0062] The potential gradient forming section 20C has a first wiring 31, a second wiring 32, and a third wiring 33. The first wiring 31 is connected to the first end of the first resistive gate section 23 that is farther from the second resistive gate section 24, i.e., one end 201 of the potential gradient forming section 20C, and a first voltage (indicated as Low voltage in the figure) is applied to this first end. The second wiring 32 is connected to the second end of the second resistive gate section 24 that is farther from the first resistive gate section 23, i.e., the other end 202 of the potential gradient forming section 20C, and a second voltage (indicated as High voltage in the figure) different from the first voltage is applied to this second end. The third wiring 33 is connected to the second end of the first resistive gate section 23 that is closer to the second resistive gate section 24, and to the first end of the second resistive gate section 24 that is closer to the first resistive gate section 23. The third wiring 33 applies a third voltage (indicated as Mid voltage in the figure) having a magnitude between the first voltage and the second voltage to the second end of the first resistive gate portion 23 and the first end of the second resistive gate portion 24. With this configuration, a potential gradient is formed between the first end (one end 201) of the first resistive gate portion 23 and the second end (the other end 202) of the second resistive gate portion 24. In the illustrated example, the third wiring 33 is connected to the extension portion 242 and also to the portion of the first resistive gate portion 23 that is aligned with the extension portion 242 in the third direction D3.

[0063] The ventilation portion 25 is provided between the first resistive gate portion 23 and the second resistive gate portion 24 in the second direction D2. The ventilation portion 25 is, for example, a gap that exists between the first resistive gate portion 23 and the second resistive gate portion 24. The ventilation portion 25 is continuous from the gap between the base portion 241 of the second resistive gate portion 24 and the first resistive gate portion 23 to the gap between the extended portion 242 of the second resistive gate portion 24 and the first resistive gate portion 23. The ventilation portion 25 is provided continuously over at least two of the plurality of pixel regions 11 (over all pixel regions 11 in the illustrated example). The first resistive gate portion 23 and the second resistive gate portion 24 are separated from each other by the ventilation portion 25.

[0064] The ventilation section 25 allows gas to pass through during the manufacturing of the solid-state imaging device 1C to terminate the surface of each pixel region 11, i.e., the interface between each pixel region 11 and the insulating region 14. The gas passes through the ventilation section 25 and enters the gap between both the first resistive gate section 23 and the second resistive gate section 24 and the insulating region 14. The gas is, for example, hydrogen. The hydrogen is absorbed by the Si contained in the pixel region 11 and the SiO contained in the insulating region 14. ２ It bonds to the dangling bond of Si at the crystal defect that occurs at the interface, thereby terminating the dangling bond. The ventilation portion 25 only needs to allow gas to pass through during the termination treatment of the surface of each pixel region 11, and may be subsequently blocked by a protective film or the like.

[0065] The effects obtained by the solid-state imaging device 1C of this embodiment, as described above, will now be explained. In the solid-state imaging device 1C of this embodiment, the potential gradient forming unit 20C has a ventilation unit 25 provided between the first resistive gate unit 23 and the second resistive gate unit 24. When manufacturing the solid-state imaging device 1C, gas for termination processing enters from the ventilation unit 25 and spreads from the ventilation unit 25 to below the first resistive gate unit 23 and the second resistive gate unit 24, thereby terminating the surface of each pixel region 11. As a result, the portion of each pixel region 11 that is not terminated is eliminated or reduced, thereby suppressing a decrease in charge transfer characteristics and an increase in dark current. In addition, by providing a ventilation unit 25 between the first resistive gate unit 23 and the second resistive gate unit 24 which are arranged side by side along the second direction D2, the first resistive gate unit 23 and the second resistive gate unit 24 can secure a sufficient width in the first direction D1. Therefore, a decrease in charge transfer characteristics can be suppressed.

[0066] As in this embodiment, the potential gradient forming unit 20C may have a first wiring 31, a second wiring 32, and a third wiring 33. The first wiring 31 applies a first voltage to the first end of the first resistive gate unit 23. The second wiring 32 applies a second voltage higher than the first voltage to the second end of the second resistive gate unit 24. The third wiring 33 applies a third voltage, which is between the first and second voltages, to the second end of the first resistive gate unit 23 and the first end of the second resistive gate unit 24. For example, with such a configuration, a potential gradient continuous from the first resistive gate unit 23 to the second resistive gate unit 24 can be formed, creating a potential gradient within each pixel region 11 extending from one end 201 to the other end 202.

[0067] As in this embodiment, the second resistive gate portion 24 may include a base portion 241 and an extended portion 242. The ventilation portion 25 may be continuous from the gap between the base portion 241 and the first resistive gate portion 23 to the gap between the extended portion 242 and the first resistive gate portion 23. Alternatively, the first resistive gate portion 23 may include a base portion and an extended portion. In that case, the ventilation portion 25 may be continuous from the gap between the base portion of the first resistive gate portion 23 and the second resistive gate portion 24 to the gap between the extended portion of the first resistive gate portion 23 and the second resistive gate portion 24. In these cases, while providing a ventilation portion 25 between the first resistive gate portion 23 and the second resistive gate portion 24, it is possible to form an uninterrupted potential gradient even at the boundary portion between the first resistive gate portion 23 and the second resistive gate portion 24. Therefore, the decrease in charge transfer characteristics due to the provision of the ventilation section 25 can be suppressed.

[0068] As in this embodiment, the first resistive gate portion 23, the second resistive gate portion 24, and the ventilation portion 25 may be continuously provided over at least two of the multiple pixel regions 11. In this case, the potential distribution can be made more uniform between at least two pixel regions 11, thereby suppressing a decrease in charge transfer characteristics.

[0069] [Second Modification] Figure 8 shows the configuration of a solid-state imaging device 1D according to the second modification of the present disclosure. Part 8(a) of Figure 8 shows a plan view of the solid-state imaging device 1D. Part 8(b) of Figure 8 schematically shows a cross section perpendicular to the second direction D2 of the solid-state imaging device 1D. Part 8(c) of Figure 8 schematically shows a cross section perpendicular to the first direction D1 of the potential gradient forming unit 20D provided in the solid-state imaging device 1D. The solid-state imaging device 1D of this modification differs from the solid-state imaging device 1C of the second embodiment in the configuration of the potential gradient forming unit, and is consistent with the solid-state imaging device 1C of the second embodiment in other respects. The solid-state imaging device 1D of this modification is equipped with a potential gradient forming unit 20D instead of the potential gradient forming unit 20C of the second embodiment.

[0070] In this modified example, the potential gradient forming section 20D has a conductive connecting member 26A instead of the third wiring 33 shown in Figure 7. In addition, the potential gradient forming section 20D has an insulating film 27. The insulating film 27 is provided over the first resistive gate section 23 and the second resistive gate section 24. The insulating film 27 is made of, for example, SiO ２ It mainly contains silicon compounds such as the above. The connecting member 26A includes a flat film portion 261 and a plurality of connecting portions 262. The flat film portion 261 is provided on the boundary between the first resistive gate portion 23 and the second resistive gate portion 24 and on the insulating film 27, and extends along the first direction D1.

[0071] Each of the multiple connection portions 262 is embedded in each of the multiple openings formed in the insulating film 27 on the boundary between the first resistive gate portion 23 and the second resistive gate portion 24. The multiple connection portions 262 are arranged in a line along the first direction D1 and are interconnected via a flat film portion 261. The flat film portion 261 is provided on the multiple connection portions 262 and is formed integrally with the multiple connection portions 262. The potentials of the multiple connection portions 262 are the same through the flat film portion 261. In addition, each of the multiple connection portions 262 is positioned above each of the multiple pixel regions 11. As shown in part 8(c), each connection portion 262 electrically connects the second end of the first resistive gate portion 23 to the first end of the second resistive gate portion 24 by contacting both the second end of the first resistive gate portion 23 on the side closer to the second resistive gate portion 24 and the first end of the second resistive gate portion 24 on the side closer to the first resistive gate portion 23. Each of the multiple connection points 262 blocks each of the multiple portions of the ventilation section 25. The gas for termination enters through the portion of the ventilation section 25 located between the multiple connection points 262. The connecting member 26A mainly consists of a metal such as aluminum (Al).

[0072] As shown in this modified example, the potential gradient forming section 20D may have a connecting member 26A. The connecting member 26A includes a plurality of connecting sections 262 that electrically connect the second end of the first resistive gate section 23 to the first end of the second resistive gate section 24. For example, with such a configuration, a potential gradient continuous from the first resistive gate section 23 to the second resistive gate section 24 can be formed, creating a potential gradient within each pixel region 11 that extends from one end 201 to the other end 202.

[0073] As shown in this modified example, each of the multiple connection parts 262 may block each of the multiple parts of the ventilation part 25. In this case, the first resistive gate part 23 and the second resistive gate part 24 can be efficiently connected by the shortest conductive path.

[0074] As shown in this modified example, each of the multiple connection portions 262 of the connecting member 26A may be positioned above each of the multiple pixel regions 11. In this case, the occurrence of bias in the potential distribution in the region around the ventilation portion 25 of the first resistive gate portion 23 and the second resistive gate portion 24 can be suppressed, thereby suppressing a decrease in charge transfer characteristics.

[0075] [Third Modification] Figure 9 shows the configuration of a solid-state imaging device 1E according to the third modification of the present disclosure. Part 9(a) of Figure 9 shows a plan view of the solid-state imaging device 1E. Part 9(b) of Figure 9 schematically shows a cross section perpendicular to the second direction D2 of the solid-state imaging device 1E. Part 9(c) of Figure 9 schematically shows a cross section perpendicular to the first direction D1 of the potential gradient forming unit 20E provided in the solid-state imaging device 1E. The solid-state imaging device 1E of this modification differs from the solid-state imaging device 1C of the second embodiment in the configuration of the potential gradient forming unit, and is consistent with the solid-state imaging device 1C of the second embodiment in other respects. The solid-state imaging device 1E of this modification is equipped with a potential gradient forming unit 20E instead of the potential gradient forming unit 20C of the second embodiment.

[0076] In this modified example, the potential gradient forming section 20E has a plurality of conductive connecting members 26B instead of the third wiring 33 shown in Figure 7. In addition, the potential gradient forming section 20E has an insulating film 27. The configuration of the insulating film 27 is the same as that of the insulating film 27 in the second modified example. Each connecting member 26B includes a connecting portion 262 and a flat film portion 263. In this modified example, each of the connecting portions 262 of the plurality of connecting members 26B is positioned above each of the plurality of pixel separation regions 12. Except for this, the configuration of the connecting portions 262 of the plurality of connecting members 26B is the same as that of the plurality of connecting portions 262 in the second modified example. The flat film portion 263 is provided on the boundary between the first resistive gate portion 23 and the second resistive gate portion 24 and on the insulating film 27. The flat film portion 263 is provided on the connecting portion 262 and is formed integrally with the connecting portion 262. Unlike the flat membrane portion 261 of the second modified example, the flat membrane portion 263 of this modified example is separated for each connecting member 26B.

[0077] As shown in this modified example, the potential gradient forming section 20E may have a plurality of connecting members 26B, each including a connecting section 262. For example, with such a configuration, a potential gradient continuous from the first resistive gate section 23 to the second resistive gate section 24 can be formed, creating a potential gradient within each pixel region 11 extending from one end 201 to the other end 202.

[0078] As shown in this modified example, each of the connection portions 262 of the multiple connecting members 26B may be arranged on each of the multiple pixel separation regions 12. In this case, when light is incident on each pixel region 11 through the potential gradient forming portion 20E, the connection members 26B can avoid obstructing the incidence of light to each pixel region 11. In addition, the degree to which the connection portions 262 obstruct the entry of the gas for termination processing onto the surface of each pixel region 11 can be reduced.

[0079] As shown in this modified example, each of the connection portions 262 of the multiple connecting members 26B may be positioned on each of the multiple pixel separation regions 12, and the flat film portion 263 may be separated for each connecting member 26B. This further prevents the connecting members 26B from obstructing the incidence of light to each pixel region 11 when light is incident on each pixel region 11 through the potential gradient forming portion 20E.

[0080] [Fourth Modification] Figure 10 shows the configuration of a solid-state imaging device 1F according to the fourth modification of the present disclosure. Part (a) of Figure 10 shows a plan view of the solid-state imaging device 1F. Part (b) of Figure 10 schematically shows a cross section perpendicular to the second direction D2 of the solid-state imaging device 1F. Part (c) of Figure 10 schematically shows a cross section perpendicular to the first direction D1 of the potential gradient forming unit 20F provided in the solid-state imaging device 1F. The solid-state imaging device 1F of this modification differs from the solid-state imaging device 1C of the second embodiment in the configuration of the potential gradient forming unit, and is consistent with the solid-state imaging device 1C of the second embodiment in other respects. The solid-state imaging device 1F of this modification is equipped with a potential gradient forming unit 20F instead of the potential gradient forming unit 20C of the second embodiment.

[0081] In this modified example, the potential gradient forming section 20F has a conductive connecting member 26C instead of the third wiring 33 shown in Figure 7. In addition, the potential gradient forming section 20F has an insulating film 27. The connecting member 26C includes a flat film portion 264 and a plurality of connecting portions 262. The arrangement and configuration of the plurality of connecting portions 262 and the insulating film 27 are the same as those of the plurality of connecting portions 262 and the insulating film 27 in the second modified example. The flat film portion 264 is provided on the insulating film 27. Unlike the flat film portion 261 in the second modified example, the flat film portion 264 in this modified example covers the entire surface of the plurality of pixel regions 11, not just the boundary between the first resistive gate portion 23 and the second resistive gate portion 24. In the illustrated example, the flat film portion 264 is provided over the entire surface of the first resistive gate portion 23 and the entire surface of the second resistive gate portion 24. The flat film portion 264 does not necessarily have to cover the entire surface of the photoelectric conversion region, which includes the multiple pixel separation regions 12. Furthermore, the flat film portion 264 has multiple apertures 265 formed therein. In one example, the multiple apertures 265 are each located on the multiple pixel separation regions 12.

[0082] As shown in this modified example, the potential gradient forming section 20F may have a connecting member 26C that includes a plurality of connecting sections 262. For example, with such a configuration, a potential gradient continuous from the first resistive gate section 23 to the second resistive gate section 24 can be formed, creating a potential gradient within each pixel region 11 that extends from one end 201 to the other end 202.

[0083] As shown in this modified example, the flat film portion 264 may be provided so as to cover the entire surface of a plurality of pixel regions 11. In this case, light incident from the back surface of the solid-state imaging device that is not absorbed by the pixel regions 11 but passes through the pixel regions 11, in particular long-wavelength light that easily penetrates Si, can be reflected by the flat film portion 264 and absorbed by the pixel regions 11. Therefore, the photoelectric conversion efficiency can be increased.

[0084] As shown in this modified example, a plurality of openings 265 may be formed in the flat membrane portion 264. In this case, the gas for termination processing can be efficiently delivered to the ventilation portion 25 through the plurality of openings 265.

[0085] The solid-state imaging apparatus according to this disclosure is not limited to the embodiments described above, and various other modifications are possible. For example, the embodiments described above may be combined with each other depending on the required purpose and effect.

[0086] In the first embodiment, the multiple resistive gate sections 21 are completely separated by a plurality of ventilation sections 22 extending from one end 201 to the other end 202, but the multiple resistive gate sections 21 may be connected to each other at one end 201 and / or the other end 202. In the second embodiment, the first resistive gate section 23 and the second resistive gate section 24 are completely separated by a ventilation section 25, but the first resistive gate section 23 and the second resistive gate section 24 may be connected to each other at both ends or one end in the first direction D1.

[0087] In the embodiments and modifications described above, Si was used as an example of the constituent material for the plurality of pixel regions 11 and semiconductor regions 13, but these constituent materials may be other semiconductor materials other than Si (for example, compound semiconductor materials).

[0088] In the above embodiments and modifications, the case in which the potential gradually increases from one end 201 to the other end 202 of the potential gradient forming section is illustrated. However, the potential may also gradually decrease from one end 201 to the other end 202 of the potential gradient forming section. In that case, the relationship between the impurity polarity and potential of the semiconductor will be the opposite of that in the above embodiments and modifications.

[0089] While the principles of the present invention have been illustrated and described in preferred embodiments, it will be recognized by those skilled in the art that the present invention can be modified in arrangement and detail without departing from such principles. The present invention is not limited to the specific configurations disclosed in these embodiments. Accordingly, all modifications and changes arising from the scope of the claims and their spirit are claimed.

[0090] 1A-1F... Solid-state imaging device, 2... Pixel, 10A, 10B... Photoelectric conversion unit, 11... Pixel region, 12... Pixel separation region, 13, 15-17... Semiconductor region, 14... Insulation region, 20A-20F... Potential gradient formation unit, 21... Resistive gate unit, 22... Ventilation unit, 23... First resistive gate unit, 24... Second resistive gate unit, 25... Ventilation unit, 26A-26C... Connecting member, 27... Insulating film, 28a... Holding electrode, 28b, 28c... Transfer electrode ,29...resistive gate, 31...first wiring, 32...second wiring, 33...third wiring, 118...unterminating area, 201...one end (low potential end), 202...other end (high potential end), 241...base, 242...extension, 261, 263, 264...flat film portion, 262...connection portion, 265, 291...opening, d...distance, D1...first direction, D2...second direction, D3...third direction, E1-E5...potential energy, J...current, Q...charge, W1-W4...width.

Claims

1. A solid-state imaging device comprising: a photoelectric conversion unit having a plurality of pixel regions that generate an electric charge in response to incident light, and a plurality of pixel separation regions that separate the plurality of pixel regions from each other, wherein the plurality of pixel regions and the plurality of pixel separation regions are arranged alternately along a first direction; a potential gradient forming unit provided on the photoelectric conversion unit and forming a potential gradient on the photoelectric conversion unit such that the potential gradually changes from one end to the other in a second direction intersecting the first direction, wherein the potential gradient forming unit has a plurality of resistive gate portions that each cover the plurality of pixel regions, and a plurality of elongated ventilation portions provided on each of the plurality of pixel separation regions, wherein the length along the second direction is greater than the width along the first direction, and the average value of the width of each ventilation portion in the second direction is smaller than the average value of the width along the first direction of the portion of each resistive gate portion sandwiched between the plurality of ventilation portions in the second direction.

2. The solid-state imaging apparatus according to claim 1, wherein the width of each pixel region along the first direction, the width of each pixel separation region along the first direction, the width of each resistive gate portion, and the width of each ventilation portion are substantially constant from one end to the other.

3. The solid-state imaging apparatus according to claim 1, wherein the width of each pixel region along the first direction and the width of each resistive gate portion gradually increase from one end to the other, and the width of each pixel separation region along the first direction and the width of each ventilation portion gradually decrease from one end to the other.

4. The solid-state imaging apparatus according to any one of claims 1 to 3, wherein each ventilation section is a gap formed between the plurality of resistive gate sections.

5. The solid-state imaging apparatus according to any one of claims 1 to 4, wherein each ventilation section is provided continuously from one end to the other end of the potential gradient forming section, and the plurality of resistive gate sections are separated from each other by the plurality of ventilation sections.

6. The solid-state imaging apparatus according to any one of claims 1 to 5, wherein the average value of the width of each ventilation portion in the second direction is smaller than the width of each pixel separation region along the first direction.

7. A photoelectric conversion unit having a plurality of pixel regions that generate charge in response to incident light and a plurality of pixel separation regions that separate the plurality of pixel regions from each other, wherein the plurality of pixel regions and the plurality of pixel separation regions are arranged alternately along a first direction; a potential gradient forming unit provided on the photoelectric conversion unit and forming a potential gradient on the photoelectric conversion unit such that the potential gradually changes from one end to the other in a second direction intersecting the first direction, wherein the potential gradient forming unit comprises: a first resistive gate portion that covers a part of each pixel region; a second resistive gate portion arranged in the second direction adjacent to the first resistive gate portion and covering at least a part of the remainder of each pixel region; a ventilation portion provided between the first resistive gate portion and the second resistive gate portion; and a first wiring that applies a first voltage to the first end of the first resistive gate portion on the side farther from the second resistive gate portion. A solid-state imaging device comprising: a second wiring that applies a second voltage different from the first voltage to the second end of the second resistive gate portion that is farther from the first resistive gate portion; and a third wiring that applies a third voltage having a magnitude between the first voltage and the second voltage to the second end of the first resistive gate portion that is close to the second resistive gate portion, and to the first end of the second resistive gate portion that is close to the first resistive gate portion.

8. A photoelectric conversion unit having a plurality of pixel regions that generate charge in response to incident light and a plurality of pixel separation regions that separate the plurality of pixel regions from each other, wherein the plurality of pixel regions and the plurality of pixel separation regions are arranged alternately along a first direction; a potential gradient forming unit provided on the photoelectric conversion unit and forming a potential gradient on the photoelectric conversion unit such that the potential gradually changes from one end to the other in a second direction intersecting the first direction, wherein the potential gradient forming unit comprises: a first resistive gate portion that covers a part of each pixel region; a second resistive gate portion arranged in the second direction adjacent to the first resistive gate portion and covering at least a part of the remainder of each pixel region; a ventilation portion provided between the first resistive gate portion and the second resistive gate portion; and a first wiring that applies a first voltage to the first end of the first resistive gate portion on the side farther from the second resistive gate portion. A solid-state imaging device comprising: a plurality of connection points that electrically connect the second end of the first resistive gate portion on the side closer to the second resistive gate portion to the first end of the second resistive gate portion on the side closer to the first resistive gate portion; and a second wiring that applies a second voltage different from the first voltage to the second end of the second resistive gate portion on the side farther from the first resistive gate portion.

9. The solid-state imaging apparatus according to claim 8, wherein each of the plurality of connection parts blocks each of the plurality of parts of the ventilation part.

10. The solid-state imaging apparatus according to claim 8 or 9, wherein each of the plurality of connection portions is arranged on each of the plurality of pixel separation regions.

11. The solid-state imaging apparatus according to claim 8 or 9, wherein each of the plurality of connection portions is arranged on each of the plurality of pixel regions.

12. The solid-state imaging apparatus according to any one of claims 8 to 11, wherein the potential gradient forming portion further comprises a metal flat film portion that connects the plurality of connecting portions to each other, the flat film portion has a plurality of openings formed therein, and the flat film portion covers the entire surface of the plurality of pixel regions.

13. The solid-state imaging apparatus according to any one of claims 7 to 12, wherein the first resistive gate portion, the second resistive gate portion, and the ventilation portion are continuously provided over at least two pixel regions among the plurality of pixel regions.

14. The solid-state imaging apparatus according to any one of claims 7 to 13, wherein one of the first resistive gate portion and the second resistive gate portion includes a base portion provided on the same plane as the other resistive gate portion of the first resistive gate portion and the second resistive gate portion, and an extending portion extending from the base portion and running parallel to the other resistive gate portion in a third direction intersecting both the first and second directions, and the ventilation portion is continuous from the gap between the base portion and the other resistive gate portion to the gap between the extending portion and the other resistive gate portion.

15. The solid-state imaging apparatus according to claim 7, wherein one of the first resistive gate portion and the second resistive gate portion includes a base portion provided on the same plane as the other resistive gate portion of the first resistive gate portion and the second resistive gate portion, and an extended portion extending from the base portion and aligned with the other resistive gate portion in a third direction intersecting both the first and second directions, the ventilation portion is continuous from the gap between the base portion and the other resistive gate portion to the gap between the extended portion and the other resistive gate portion, and the third wiring is connected to the extended portion and the portion of the other resistive gate portion aligned with the extended portion in the third direction.

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