Light detection element

Abstract

The present invention relates to a light detection element comprising a photoelectric conversion unit, the photoelectric conversion unit comprising: a first electrode; a second electrode; a photoelectric conversion layer provided between the first electrode and the second electrode; and a composite oxide layer including an indium composite oxide disposed between the first electrode and the photoelectric conversion layer, the composite oxide layer including a first layer and a second layer, where the first layer is disposed between the first electrode and the second layer, and where the second layer is disposed between the first electrode and the second layer. A ratio of a carrier mobility of the second layer to a carrier mobility of the first layer is greater than or equal to 1 * 10 <-6 > and less than or equal to 0.1.

Description

[0001] This application is a divisional application of the patent application with application number 201880051512.7, filed on May 11, 2018, and with the invention name “IMAGING ELEMENT, STACKED IMAGING ELEMENT AND SOLID-STATE IMAGING DEVICE”. Technical Field

[0002] The present invention relates to an imaging element, a stacked imaging element, and a solid-state imaging device. Background Art

[0003] In recent years, stacked imaging elements have attracted attention as imaging elements for use in image sensors and other applications. These elements have a structure in which a photoelectric conversion layer (light-receiving layer) is sandwiched between two electrodes. Furthermore, stacked imaging elements require a structure in which signal charge generated in the photoelectric conversion layer based on photoelectric conversion is accumulated and transferred. Conventional structures require a structure capable of accumulating and transferring signal charge to a floating drain (FD) electrode, and high-speed transmission is required to prevent signal charge delay.

[0004] An imaging element (photoelectric conversion element) for solving the above-mentioned problem is disclosed in, for example, Japanese Patent Application Laid-Open No. 2016-63165. This imaging element includes:

[0005] an accumulation electrode formed on the first insulating layer;

[0006] a second insulating layer formed on the accumulation electrode;

[0007] a semiconductor layer formed to cover the accumulation electrode and the second insulating layer;

[0008] a collecting electrode formed in contact with the semiconductor layer and separated from the accumulating electrode;

[0009] a photoelectric conversion layer formed on the semiconductor layer; and

[0010] An upper electrode is formed on the photoelectric conversion layer.

[0011] Imaging elements using organic semiconductor materials for their photoelectric conversion layers are capable of photoelectrically converting specific colors (wavelength bands). Furthermore, due to this characteristic, when these imaging elements are used as imaging elements in solid-state imaging devices, a structure with stacked sub-pixels (stacked imaging elements) can be achieved, which is not possible with conventional solid-state imaging devices. Each sub-pixel comprises a combination of an on-chip color filter layer (OCCF) and an imaging element, and the sub-pixels are arranged two-dimensionally (see, for example, Japanese Patent Application Laid-Open No. 2011-138927). Furthermore, since demosaicing is not required, false colors are not generated. In the following description, for convenience, an imaging element including a photoelectric conversion unit arranged on or above a semiconductor substrate may be referred to as a "first type imaging element"; for convenience, the photoelectric conversion unit constituting the first type imaging element may be referred to as a "first type photoelectric conversion unit"; for convenience, an imaging element arranged in a semiconductor substrate may be referred to as a "second type imaging element"; for convenience, the photoelectric conversion unit constituting the second type imaging element may be referred to as a "second type photoelectric conversion unit".

[0012] Figure 78 A configuration example of a conventional stacked image pickup element (stacked solid-state image pickup device) is shown. Figure 78 In the illustrated example, a third photoelectric conversion unit 343A and a second photoelectric conversion unit 341A (these are second-type photoelectric conversion units that constitute the third and second imaging elements 343 and 341, respectively, as second-type imaging elements) are stacked together and formed on a semiconductor substrate 370. Furthermore, a first photoelectric conversion unit 310A, which is a first-type photoelectric conversion unit, is provided above the semiconductor substrate 370 (specifically, above the second imaging element 341). The first photoelectric conversion unit 310A includes a first electrode 321, a photoelectric conversion layer 323 containing an organic material, and a second electrode 322, and constitutes the first imaging element 310, which is a first-type imaging element. The second and third photoelectric conversion units 341A and 343A can, for example, perform photoelectric conversion on blue light and red light, respectively, due to differences in absorption coefficients. Furthermore, the first photoelectric conversion unit 310A can perform photoelectric conversion on green light, for example.

[0013] The charges generated by photoelectric conversion in the second photoelectric conversion unit 341A and the third photoelectric conversion unit 343A are temporarily accumulated in the second photoelectric conversion unit 341A and the third photoelectric conversion unit 343A. These charges are then transferred to the second floating diffusion layer FD2 and the third floating diffusion layer FD3, respectively, via a vertical transistor (gate portion 345 shown) and a transfer transistor (gate portion 346 shown). These charges are then output to an external readout circuit (not shown). These transistors and the floating diffusion layers FD2 and FD3 are also formed in the semiconductor substrate 370.

[0014] The charge generated by photoelectric conversion in the first photoelectric conversion unit 310A is accumulated in the first floating diffusion layer FD1 formed in the semiconductor substrate 370 via the contact hole portion 361 and the wiring layer 362. Furthermore, the first photoelectric conversion unit 310A is also connected to the gate portion 352 of the amplifier transistor for converting the charge into a voltage via the contact hole portion 361 and the wiring layer 362. Furthermore, the first floating diffusion layer FD1 constitutes part of the reset transistor (gate portion 351 is shown). Reference numeral 371 denotes an element isolation region, reference numeral 372 denotes an oxide film formed on the surface of the semiconductor substrate 370, reference numerals 376 and 381 denote interlayer insulating layers, reference numeral 383 denotes an insulating layer, and reference numeral 314 denotes an on-chip microlens.

[0015] Reference List

[0016] Patent Literature

[0017] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-63165

[0018] Patent Document 2: Japanese Patent Application Laid-Open No. 2011-138927 Summary of the Invention

[0019] Problems to be solved by the present invention

[0020] Incidentally, the technology disclosed in Japanese Patent Application Laid-Open No. 2016-63165 uses IGZO as a material constituting the semiconductor layer. However, when a semiconductor layer containing IGZO is used, there is a significant difference between the state density of the organic semiconductor material constituting the photoelectric conversion layer and the state density of the IGZO constituting the semiconductor layer. For example, the state density of the organic semiconductor material is approximately 1×10 21 cm -3 , the state density of IGZO is about 1×10 18 cm -3Therefore, when carriers (e.g., photoelectrons) generated by photoelectric conversion flow from the photoelectric conversion layer into the semiconductor layer, carrier stagnation is likely to occur at the interface between the photoelectric conversion layer and the semiconductor layer. As a result, the photoresponsiveness of the imaging element (photoelectric conversion element) is adversely affected.

[0021] Therefore, the object of the present invention is to provide an imaging element having a construction and structure that hardly adversely affects light responsiveness (i.e., an imaging element in which the charge accumulated in the photoelectric conversion layer has excellent transfer characteristics) and a stacked imaging element and a solid-state imaging device each including the imaging element.

[0022] Technical solutions to the problem

[0023] In order to achieve the above-mentioned object, an imaging element (photoelectric conversion element) according to a first aspect of the present invention includes:

[0024] a photoelectric conversion unit formed by stacking a first electrode, a photoelectric conversion layer, and a second electrode,

[0025] A composite oxide layer including indium composite oxide is formed between the first electrode and the photoelectric conversion layer.

[0026] The composite oxide layer includes a first layer adjacent to the first electrode and a second layer adjacent to the photoelectric conversion layer, and

[0027] The first layer has a higher indium composition than the second layer.

[0028] In order to achieve the above-mentioned object, an imaging element (photoelectric conversion element) according to a second aspect of the present invention includes:

[0029] a photoelectric conversion unit formed by stacking a first electrode, a photoelectric conversion layer, and a second electrode,

[0030] A composite oxide layer including an indium-gallium-zinc composite oxide is formed between the first electrode and the photoelectric conversion layer.

[0031] The composite oxide layer includes a first layer adjacent to the first electrode and a second layer adjacent to the photoelectric conversion layer.

[0032] The first layer has a higher indium composition than the second layer, or

[0033] the first layer has a lower gallium composition than the second layer, or

[0034] The first layer has a higher zinc composition than the second layer. Alternatively, the oxygen atomic content in the first layer is lower than the oxygen atomic content in the second layer.

[0035] In order to achieve the above-mentioned object, an imaging element (photoelectric conversion element) according to a third aspect of the present invention includes:

[0036] a photoelectric conversion unit formed by stacking a first electrode, a photoelectric conversion layer, and a second electrode,

[0037] A composite oxide layer containing indium composite oxide (indium-gallium-zinc composite oxide) is formed between the first electrode and the photoelectric conversion layer.

[0038] The composite oxide layer includes a first layer adjacent to the first electrode and a second layer adjacent to the photoelectric conversion layer, and

[0039] The first layer has higher carrier mobility than the second layer.

[0040] In order to achieve the above-mentioned object, an imaging element (photoelectric conversion element) according to a fourth aspect of the present invention includes:

[0041] a photoelectric conversion unit formed by stacking a first electrode, a photoelectric conversion layer, and a second electrode,

[0042] A composite oxide layer containing indium composite oxide (indium-gallium-zinc composite oxide) is formed between the first electrode and the photoelectric conversion layer.

[0043] The composite oxide layer includes a first layer adjacent to the first electrode and a second layer adjacent to the photoelectric conversion layer, and

[0044] The first layer has a lower density of states than the second layer.

[0045] The stacked image pickup element of the present invention for achieving the above-mentioned object includes at least one image pickup element according to the first to fourth aspects of the present invention.

[0046] A solid-state imaging device according to a first aspect of the present invention for achieving the above-mentioned object includes a plurality of imaging elements according to the first to fourth aspects of the present invention. Furthermore, a solid-state imaging device according to a second aspect of the present invention for achieving the above-mentioned object includes a plurality of stacked imaging elements according to the present invention.

[0047] Beneficial effects of the present invention

[0048] In the imaging element etc. according to the first and second aspects of the present invention (described later), the composition of each layer is limited to a composite oxide layer having at least two layers. In the imaging element etc. according to the third and fourth aspects of the present invention (described later), the relationship between the carrier mobility or state density of each layer is limited to a composite oxide layer having at least two layers. Therefore, when the carriers (for example, photoelectrons) generated by photoelectric conversion flow from the photoelectric conversion layer into the composite oxide layer, carrier stagnation hardly occurs at the interface between the photoelectric conversion layer and the composite oxide layer. In addition, the carrier transport capability of the photoelectric conversion layer and the composite oxide layer as a whole can be improved. Therefore, it is possible to provide an imaging element that has no adverse effect on the light responsiveness of the imaging element and has excellent transport characteristics for the charge accumulated in the photoelectric conversion layer. In addition, the imaging element etc. of the present invention (described later) has a two-layer structure of a composite oxide layer and a photoelectric conversion layer. Therefore, it is possible to prevent recombination during charge accumulation, improve the transfer efficiency of the charge accumulated in the photoelectric conversion layer to the first electrode, and suppress the generation of dark current. Note that the effects described here are merely illustrative and not restrictive. In addition, there may be other beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a schematic partial cross-sectional view of the image pickup element of Example 1.

[0050] Figure 2 This is an equivalent circuit diagram of the imaging element of Example 1.

[0051] Figure 3 This is an equivalent circuit diagram of the imaging element of Example 1.

[0052] Figure 4 This is a schematic layout diagram of a first electrode, a charge storage electrode, and a transistor constituting a control unit constituting the image pickup element of Example 1.

[0053] Figure 5 Schematically shows the potential state of each portion during operation of the imaging element of Example 1.

[0054] Figure 6A 、 6B and 6C are used to illustrate Figure 5 (Example 1), Figure 20 and 21 (Example 4), and Figure 32 and 33 (Example 6) Equivalent circuit diagram of each part of the imaging element of Example 1, Example 4 and Example 6.

[0055] Figure 7Schematic layout diagram of the first electrode and the charge storage electrode constituting the image pickup element of Example 1.

[0056] Figure 8 This is a schematic perspective view of a first electrode, a charge storage electrode, a second electrode, and a contact hole portion constituting the image pickup element of Example 1.

[0057] Figure 9 This is an equivalent circuit diagram of a modified example of the imaging element of Example 1.

[0058] Figure 10 It is composed Figure 9 Schematic layout diagram of a first electrode, a charge storage electrode, and transistors constituting a control unit of a modified example of the imaging element of Example 1 shown.

[0059] Figure 11 This is a schematic partial cross-sectional view of the image pickup element of Example 2.

[0060] Figure 12 This is a schematic partial cross-sectional view of the image pickup element of Example 3.

[0061] Figure 13 This is a schematic partial cross-sectional view of a modification of the imaging element of Example 3.

[0062] Figure 14 This is a schematic partial cross-sectional view of another modified example of the imaging element of Example 3.

[0063] Figure 15 This is a schematic partial cross-sectional view of still another modified example of the imaging element of Example 3.

[0064] Figure 16 This is a schematic partial cross-sectional view of a portion of the imaging element of Example 4.

[0065] Figure 17 This is an equivalent circuit diagram of the imaging element of Example 4.

[0066] Figure 18 This is an equivalent circuit diagram of the imaging element of Example 4.

[0067] Figure 19 This is a schematic layout diagram of a first electrode, a transfer control electrode, a charge accumulation electrode, and a transistor constituting a control unit that constitute the image pickup element of Example 4.

[0068] Figure 20 This is a diagram schematically showing the potential state of each portion during operation of the imaging element of Example 4.

[0069] Figure 21Schematically showing the potential states of various parts during another operation of the imaging element of Example 4.

[0070] Figure 22 This is a schematic layout diagram of the first electrode, transfer control electrode, and charge accumulation electrode that constitute the image pickup element of Example 4.

[0071] Figure 23 This is a schematic perspective view of a first electrode, a transfer control electrode, a charge storage electrode, a second electrode, and a contact hole portion that constitute the image pickup element of Example 4.

[0072] Figure 24 This is a schematic layout diagram of a first electrode, a transfer control electrode, a charge storage electrode, and transistors constituting a control unit that constitute a modification of the imaging element of Example 4.

[0073] Figure 25 This is a schematic partial cross-sectional view of a portion of the imaging element of Example 5.

[0074] Figure 26 This is a schematic layout diagram of the first electrode, the charge accumulation electrode, and the charge discharge electrode that constitute the image pickup element of Example 5.

[0075] Figure 27 This is a schematic perspective view of a first electrode, a charge storage electrode, a charge discharge electrode, a second electrode, and a contact hole portion that constitute the image pickup element of Example 5.

[0076] Figure 28 This is a schematic partial cross-sectional view of the imaging element of Example 6.

[0077] Figure 29 This is an equivalent circuit diagram of the imaging element of Example 6.

[0078] Figure 30 This is an equivalent circuit diagram of the imaging element of Example 6.

[0079] Figure 31 This is a schematic layout diagram of a first electrode and a charge storage electrode constituting the image pickup element of Example 6, and transistors constituting a control unit.

[0080] Figure 32 This is a diagram schematically showing the potential state of each portion during operation of the imaging element of Example 6.

[0081] Figure 33 This is a diagram schematically showing the potential state of each portion during another operation period (transfer period) of the imaging element of Example 6.

[0082] Figure 34This is a schematic layout diagram of the first electrode and the charge storage electrode constituting the imaging element of Example 6.

[0083] Figure 35 This is a schematic perspective view of a first electrode, a charge storage electrode, a second electrode, and a contact hole portion that constitute the image pickup element of Example 6.

[0084] Figure 36 This is a schematic layout diagram of the first electrode and the charge storage electrode constituting a modified example of the imaging element of Example 6.

[0085] Figure 37 This is a schematic partial cross-sectional view of the imaging element of Example 7.

[0086] Figure 38 This is a schematic partial cross-sectional view obtained by enlarging a portion where a charge accumulation electrode, a photoelectric conversion layer, and a second electrode are stacked in the image pickup element of Example 7.

[0087] Figure 39 This is a schematic layout diagram of a first electrode and a charge storage electrode constituting a modification of the imaging element of Example 7, and transistors constituting a control unit.

[0088] Figure 40 This is a schematic partial cross-sectional view obtained by enlarging a portion where a charge accumulation electrode, a photoelectric conversion layer, and a second electrode are stacked in the image pickup element of Example 8.

[0089] Figure 41 This is a schematic partial cross-sectional view of the imaging element of Example 9.

[0090] Figure 42 Schematic partial cross-sectional views of the image pickup elements of Example 10 and Example 11.

[0091] Figure 43A and 43B This is a schematic plan view of the charge accumulation electrode segment in Example 11.

[0092] Figure 44A and 44B This is an exemplary plan view of the charge accumulation electrode segment in Example 11.

[0093] Figure 45 This is a schematic layout diagram of a first electrode and a charge storage electrode constituting the image pickup element of Example 11, and transistors constituting a control unit.

[0094] Figure 46 This is a schematic layout diagram of the first electrode and the charge storage electrode constituting a modified example of the imaging element of Example 11.

[0095] Figure 47Schematic partial cross-sectional views of the imaging elements of Example 12 and Example 11.

[0096] Figure 48A and 48B This is a schematic plan view of the charge accumulation electrode segment in Example 12.

[0097] Figure 49 It is a schematic plan view of a first electrode and a charge accumulation electrode section in the solid-state imaging device of Example 13.

[0098] Figure 50 It is a schematic plan view of a first electrode and a charge accumulation electrode segment in a first modification example of the solid-state imaging device of Example 13.

[0099] Figure 51 It is a schematic plan view of a first electrode and a charge accumulation electrode segment in a second modification of the solid-state imaging device of Example 13.

[0100] Figure 52 It is a schematic plan view of a first electrode and a charge accumulation electrode segment in a third modification of the solid-state imaging device of Example 13.

[0101] Figure 53 It is a schematic plan view of a first electrode and a charge accumulation electrode segment in a fourth modification of the solid-state imaging device of Example 13.

[0102] Figure 54 It is a schematic plan view of the first electrode and the charge accumulation electrode segment in the fifth modification of the solid-state imaging device of Example 13.

[0103] Figure 55 It is a schematic plan view of a first electrode and a charge accumulation electrode segment in a sixth modification of the solid-state imaging device of Example 13.

[0104] Figure 56 It is a schematic plan view of the first electrode and the charge accumulation electrode segment in the seventh modification of the solid-state imaging device of Example 13.

[0105] Figure 57 It is a schematic plan view of the first electrode and the charge accumulation electrode segment in the eighth modification of the solid-state imaging device of Example 13.

[0106] Figure 58 It is a schematic plan view of the first electrode and the charge accumulation electrode segment in the ninth modification of the solid-state imaging device of Example 13.

[0107] Figure 59A 、 59B 59A and 59B are diagrams each showing an example of readout driving in the image pickup element block of Example 13.

[0108] Figure 60 It is a schematic plan view of a first electrode and a charge accumulation electrode section in the solid-state imaging device of Example 14.

[0109] Figure 61 It is a schematic plan view of a first electrode and a charge accumulation electrode segment in a modification of the solid-state imaging device of Example 14.

[0110] Figure 62 It is a schematic plan view of a first electrode and a charge accumulation electrode segment in a modification of the solid-state imaging device of Example 14.

[0111] Figure 63 It is a schematic plan view of a first electrode and a charge accumulation electrode segment in a modification of the solid-state imaging device of Example 14.

[0112] Figure 64 This is a schematic partial cross-sectional view of another modified example of the imaging element in Example 1.

[0113] Figure 65 This is a schematic partial cross-sectional view of yet another modified example of the imaging element in Example 1.

[0114] Figure 66A 、 66B 66C and 66C are respectively enlarged schematic partial cross-sectional views of a first electrode portion and the like of still another modified example of the image pickup element of Example 1.

[0115] Figure 67 This is an enlarged schematic partial cross-sectional view of a charge discharge electrode portion and the like in another modified example of the image sensor of Example 5.

[0116] Figure 68 This is a schematic partial cross-sectional view of yet another modified example of the image pickup element of Example 1.

[0117] Figure 69 This is a schematic partial cross-sectional view of yet another modified example of the image pickup element of Example 1.

[0118] Figure 70 This is a schematic partial cross-sectional view of yet another modified example of the imaging element in Example 1.

[0119] Figure 71 This is a schematic partial cross-sectional view of another modified example of the imaging element of Example 4.

[0120] Figure 72 This is a schematic partial cross-sectional view of yet another modified example of the image pickup element of Example 1.

[0121] Figure 73This is a schematic partial cross-sectional view of yet another modified example of the imaging element of Example 4.

[0122] Figure 74 This is a schematic partial cross-sectional view obtained by enlarging a portion where a charge storage electrode, a photoelectric conversion layer, and a second electrode are stacked in a modification of the image pickup element of Example 7.

[0123] Figure 75 This is a schematic partial cross-sectional view obtained by enlarging a portion where a charge storage electrode, a photoelectric conversion layer, and a second electrode are stacked in a modification of the image pickup element of Example 8.

[0124] Figure 76 This is a conceptual diagram of the solid-state imaging device of Example 1.

[0125] Figure 77 This is a conceptual diagram showing an example in which a solid-state imaging device including an imaging element and the like of the present invention is used in an electronic device (camera).

[0126] Figure 78 This is a conceptual diagram of a conventional stacked-type imaging element (stacked-type solid-state imaging device). DETAILED DESCRIPTION

[0127] Hereinafter, the present invention will be described based on the embodiments with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and the various numerical values ​​and materials in each embodiment are illustrative. Note that the description will be made in the following order.

[0128] 1. General Description of the Image Sensors According to the First to Fourth Aspects of the Present Invention, the Stacked Image Sensor According to the Present Invention, and the Solid-State Image Sensors According to the First and Second Aspects of the Present Invention

[0129] 2. Embodiment 1 (Image pickup elements according to the first to fourth aspects of the present invention, stacked image pickup element according to the present invention, and solid-state image pickup device according to the second aspect of the present invention)

[0130] 3. Example 2 (Variation of Example 1)

[0131] 4. Embodiment 3 (Modification of Embodiments 1 and 2 and Solid-State Image Capturing Device According to the First Aspect of the Present Invention)

[0132] 5. Example 4 (Modification of Examples 1 to 3 and Image Pickup Element Including Transfer Control Electrode)

[0133] 6. Example 5 (Modification of Examples 1 to 4 and Image Pickup Element Including Charge Discharge Electrode)

[0134] 7. Example 6 (Modification of Examples 1 to 5 and Image Pickup Element Including Multiple Charge Accumulation Electrode Segments)

[0135] 8. Example 7 (Image pickup elements of the first and sixth structures)

[0136] 9. Example 8 (Image Pickup Elements of the Second and Sixth Structures of the Present Invention)

[0137] 10. Example 9 (Image Pickup Element with the Third Structure)

[0138] 11. Example 10 (Image Pickup Element with Fourth Structure)

[0139] 12. Example 11 (Fifth Structure of Imaging Element)

[0140] 13. Example 12 (Imaging Element of the Sixth Structure)

[0141] 14. Example 13 (Solid-state imaging devices of first and second configurations)

[0142] 15. Example 14 (Variation of Example 13)

[0143] 16. Others

[0144] <General Description of the Image Pickup Elements According to the First to Fourth Aspects of the Present Invention, the Stacked Image Pickup Element According to the Present Invention, and the Solid-State Image Pickup Devices According to the First and Second Aspects of the Present Invention>

[0145] For convenience, the image sensor according to the first aspect of the present invention, the image sensor according to the first aspect constituting the stacked image sensor according to the present invention, and the image sensor according to the first aspect constituting the solid-state image sensor device according to the first and second aspects may be collectively referred to as "the image sensor according to the first aspect of the present invention, etc.". Furthermore, for convenience, the image sensor according to the second aspect of the present invention, the image sensor according to the second aspect constituting the stacked image sensor according to the present invention, and the image sensor according to the second aspect constituting the solid-state image sensor device according to the first and second aspects may be collectively referred to as "the image sensor according to the second aspect of the present invention, etc.". Furthermore, for convenience, the image sensor according to the third aspect of the present invention, the image sensor according to the third aspect constituting the stacked image sensor according to the present invention, and the image sensor according to the third aspect constituting the solid-state image sensor device according to the first and second aspects may be collectively referred to as "the image sensor according to the third aspect of the present invention, etc.". Furthermore, for convenience, the image sensor according to the fourth aspect of the present invention, the image sensor according to the fourth aspect constituting the stacked image sensor according to the present invention, and the image sensor according to the fourth aspect constituting the solid-state image sensor device according to the first and second aspects may be collectively referred to as "the image sensor according to the fourth aspect of the present invention, etc.". Furthermore, for convenience, the image pickup elements and the like according to the first to fourth aspects of the present invention may be collectively referred to as “the image pickup element and the like of the present invention”.

[0146] In the image pickup element and the like according to the second aspect of the present invention, when the indium-gallium-zinc composite oxide is composed of (ZnO) X (Ga2O3) 1-X 、(Ga2O3) Y (In2O3) 1-Y and (In2O3) Z (ZnO) 1-Z When indicating,

[0147] The value of X in the first layer can be higher than the value of X in the second layer, or

[0148] The value of Y in the first layer can be lower than the value of Y in the second layer, or

[0149] The value of Z in the first layer may be higher than the value of Z in the second layer.

[0150] Note that there are the following seven cases.

[0151] (1) When the value of X in the first layer is higher than the value of X in the second layer

[0152] (2) When the value of Y in the first layer is lower than the value of Y in the second layer

[0153] (3) The case where the value of Z in the first layer is higher than the value of Z in the second layer

[0154] (4) The case where the value of X in the first layer is higher than the value of X in the second layer, and the value of Y in the first layer is lower than the value of Y in the second layer

[0155] (5) The case where the value of X in the first layer is higher than the value of X in the second layer, and the value of Z in the first layer is higher than the value of Z in the second layer

[0156] (6) The case where the value of Y in the first layer is lower than the value of Y in the second layer, and the value of Z in the first layer is higher than the value of Z in the second layer

[0157] (7) The case where the value of X in the first layer is higher than the value of X in the second layer, the value of Y in the first layer is lower than the value of Y in the second layer, and the value of Z in the first layer is higher than the value of Z in the second layer. <00,00987>

[0158] In addition, in this case, 0 < X < 0.875, 0 < Y < 0.875, 0.125 < Z < 0.875 (where X + Y + Z = 1.000) are satisfied. For the first layer, it is preferable that Y < 0.5. For the second layer, it is preferable that X < 0.5 and Y > 0.5.

[0159] In the imaging element and the like according to the third aspect of the present invention, it is preferable that 1×10 -6 ≤ (carrier mobility of the second layer) / (carrier mobility of the first layer) ≤ 0.1. In addition, the carrier mobility of the first layer is not limited, but it is preferably 10 cm 2 / V·s or more.

[0160] In the imaging element and the like of the present invention, the composite oxide layer is preferably ideally amorphous (for example, amorphous without a local crystal structure). It can be determined whether the composite oxide layer is amorphous based on X-ray diffraction analysis.

[0161] In the imaging element or the like according to the first, third, or fourth aspects of the present invention including the preferred embodiments and structures described above, the composite oxide layer (inorganic oxide semiconductor material layer) may contain indium-gallium-zinc composite oxide (IGZO). Furthermore, in the imaging element or the like according to the present invention including the preferred embodiments and structures described above, the composite oxide layer typically contains a conductive inorganic oxide semiconductor material that is transparent to incident light. Alternatively, in the imaging element or the like according to the first, third, or fourth aspects of the present invention including the preferred embodiments and structures described above, the composite oxide layer (inorganic oxide semiconductor material layer) may contain at least two elements selected from the group consisting of indium, tungsten, tin, and zinc. Specifically, the composite oxide layer (inorganic oxide semiconductor material layer) can include: indium tungsten oxide (IWO), a material obtained by adding tungsten (W) to indium oxide; indium-tungsten-zinc oxide (IWZO), a material obtained by adding tungsten (W) and zinc (Zn) to indium oxide; indium-tin-zinc oxide (ITZO), a material obtained by adding tin (Sn) and zinc (Zn) to indium oxide; or zinc-tin oxide (ZTO). More specifically, the composite oxide layer includes In-W oxide, In-Sn oxide, In-Zn oxide, W-Sn oxide, W-Zn oxide, Sn-Zn oxide, In-W-Sn oxide, In-W-Zn oxide, In-Sn-Zn oxide, or In-W-Sn-Zn oxide. In IWO, when the total mass of indium oxide and tungsten oxide is 100% by mass, the mass proportion of tungsten oxide is preferably 10% to 30% by mass. In addition, in IWZO, when the total mass of indium oxide, tungsten oxide and zinc oxide is 100% (mass), the mass ratio of tungsten oxide is preferably 2% to 15% (mass), and the mass ratio of zinc oxide is preferably 1% to 3% (mass). In addition, in ITZO, when the total mass of indium oxide, zinc oxide and tin oxide is 100% (mass), the mass ratio of tungsten oxide is preferably 3% to 10% (mass), and the mass ratio of tin oxide is preferably 10% to 17% (mass). However, the present invention is not limited to the above. Note that in the case where the composite oxide layer (inorganic oxide semiconductor material layer) contains at least two elements selected from the group consisting of indium, tungsten, tin and zinc, it is only necessary to form the first layer and the second layer constituting the composite oxide layer based on composition modulation.

[0162] In the imaging element of the present invention, the composite oxide layer includes a first layer adjacent to the first electrode and a second layer adjacent to the photoelectric conversion layer. The first and second layers may be stacked together, or an intermediate layer may be formed between the first and second layers.

[0163] The imaging element or the like having an intermediate layer according to the second aspect of the present invention can have the following configurations:

[0164] The value of X in the first layer is higher than the value of X in the middle layer, and the value of X in the middle layer is higher than the value of X in the second layer, or

[0165] The value of Y in the first layer is lower than the value of Y in the middle layer, and the value of Y in the middle layer is lower than the value of Y in the second layer, or

[0166] The value of Z in the first layer is higher than that in the middle layer, and the value of Z in the middle layer is higher than that in the second layer.

[0167] Furthermore, the oxygen atom content in the first layer may be lower than that in the intermediate layer, and the oxygen atom content in the intermediate layer may be lower than that in the second layer.

[0168] The intermediate layer can have a structure in which two or more layers having different values ​​of X, Y, Z, etc. are stacked together (i.e., a layer structure in which the values ​​of X, Y, Z, etc. become different in a step-by-step manner); or a structure in which the values ​​of X, Y, Z, etc. gradually become different (change).

[0169] Alternatively, the imaging element or the like having an intermediate layer according to the first aspect of the present invention can have a configuration in which the indium content in the first layer is higher than that in the intermediate layer, and the indium content in the intermediate layer is higher than that in the second layer. Furthermore, the intermediate layer can have a configuration in which two or more layers having different indium contents are stacked together (i.e., a layer configuration in which the indium contents differ stepwise), or a configuration in which the indium contents gradually differ (change).

[0170] The indium component (indium atomic content), gallium component (gallium atomic content), zinc component (zinc atomic content), and oxygen atomic content in the composite oxide layer can be analyzed based on Rutherford backscattering spectrometry (RBS) or a combination of Rutherford backscattering spectrometry and nuclear reaction analysis.

[0171] Alternatively, the imaging element or the like having an intermediate layer according to the third aspect of the present invention can have a configuration in which the carrier mobility of the first layer is higher than that of the intermediate layer, and the carrier mobility of the intermediate layer is higher than that of the second layer. Furthermore, the intermediate layer can have a configuration in which two or more layers having different carrier mobilities are stacked together (i.e., a layer configuration in which the carrier mobilities differ in a stepwise manner), or a configuration in which the carrier mobilities gradually differ (change).

[0172] The value of carrier mobility can be determined based on Hall measurement or Time-of-Flight method.

[0173] Alternatively, the imaging element or the like having an intermediate layer according to the fourth aspect of the present invention can have a configuration in which the state density of the first layer is lower than that of the intermediate layer, and the state density of the intermediate layer is lower than that of the second layer. Furthermore, the intermediate layer can have a configuration in which two or more layers having different state densities are stacked together (i.e., a layer configuration in which the state density differs stepwise), or a configuration in which the state density differs gradually (varies).

[0174] The value of the density of states in the intermediate layer can be determined based on inverse electron spectroscopy.

[0175] The composite oxide layer can have a single-layer structure (composed of one material) or a multilayer structure (composed of two or more materials). Alternatively, the material constituting the composite oxide layer located above the charge accumulation electrode described later may be different from the material constituting the composite oxide layer located above the first electrode.

[0176] The composite oxide layer can be formed based on the following methods: for example, a sputtering method using multiple sputterings with different target materials, a co-sputtering method, a sputtering method by changing the oxygen flow rate during film formation, or a pulsed laser deposition method. Specifically, a parallel plate sputtering device or a DC magnetron sputtering device is used as the sputtering device. In addition, a sputtering method using argon (Ar) gas and oxygen (O2) as process gases and using an ideal sintered body such as an IGZO sintered body, an InZnO sintered body, or an InWO sintered body as a target can be used as an example.

[0177] Note that the energy level of the composite oxide layer can be controlled by controlling the amount of oxygen (oxygen partial pressure) introduced when forming the composite oxide layer by sputtering. Specifically, the value of the oxygen partial pressure (= (O2 gas pressure) / (total pressure of Ar gas and O2 gas)) when forming the composite oxide layer by sputtering is preferably set to 0 to 0.25.

[0178] In the imaging element of the present invention including the above-mentioned preferred embodiment and structure, for example, the thickness T1 of the first layer is 1.5×10 -8 m to 3×10 -8 m, the thickness of the second layer T2 is 5×10 -8 m to 5×10 -7 m.

[0179] Furthermore, the imaging element and the like according to the first to fourth aspects of the present invention including the above-described preferred aspects and configurations can have the following aspects:

[0180] Light is incident from the second electrode,

[0181] The surface roughness Ra of the composite oxide layer at the interface between the photoelectric conversion layer and the composite oxide layer is less than 1.5 nm, and

[0182] The root mean square roughness Rq of the composite oxide layer is 2.5 nm or less. The surface roughness Ra and Rq values ​​are determined in accordance with JIS B0601:2013. This smoothness of the composite oxide layer at the interface between the photoelectric conversion layer and the composite oxide layer suppresses surface scattered reflection in the composite oxide layer and improves the bright current characteristics during photoelectric conversion. A configuration can be employed in which the surface roughness Ra of the charge storage electrode, described later, is 1.5 nm or less, and the root mean square roughness Rq of the charge storage electrode is 2.5 nm or less.

[0183] In the imaging element of the present invention, the composite oxide layer preferably has a light transmittance of 65% or more with respect to light having a wavelength of 400 nm to 660 nm. Furthermore, the charge storage electrode described later also preferably has a light transmittance of 65% or more with respect to light having a wavelength of 400 nm to 660 nm. The sheet resistance value of the charge storage electrode is preferably 3×10 Ω / □ to 1×10 3 Ω / □.

[0184] exist Figure 78 In the conventional imaging element shown, the charge generated by photoelectric conversion in the second photoelectric conversion unit 341A and the third photoelectric conversion unit 343A is temporarily accumulated in the second photoelectric conversion unit 341A and the third photoelectric conversion unit 343A, and then transferred to the second floating diffusion layer FD2 and the third floating diffusion layer FD3, respectively. Therefore, the second photoelectric conversion unit 341A and the third photoelectric conversion unit 343A can be completely depleted. However, the charge generated by photoelectric conversion in the first photoelectric conversion unit 310A is directly accumulated in the first floating diffusion layer FD1. Therefore, it is difficult to completely deplete the first photoelectric conversion unit 310A. Furthermore, as a result, kTC noise increases, random noise deteriorates, and the quality of the captured image may be reduced.

[0185] In the imaging element and the like of the present invention including the preferred aspects and configurations described above, the photoelectric conversion unit can further include an insulating layer and a charge accumulation electrode disposed separately from the first electrode and facing the composite oxide layer via the insulating layer. Note that such an imaging element may be referred to hereinafter as "an imaging element and the like of the present invention including a charge accumulation electrode."

[0186] In this way, by including a charge accumulation electrode that is arranged separately from the first electrode and faces the composite oxide layer via an insulating layer, when light irradiates the photoelectric conversion unit and the light is photoelectrically converted in the photoelectric conversion unit, charge can be stored in the composite oxide layer (or the composite oxide layer and the photoelectric conversion layer). Therefore, at the start of exposure, the charge accumulation unit can be completely depleted and the charge can be erased. As a result, the occurrence of phenomena such as increased kTC noise, deterioration of random noise, and degradation of captured image quality can be suppressed. In the following description, the composite oxide layer or the composite oxide layer and the photoelectric conversion layer may be collectively referred to as "composite oxide layer, etc."

[0187] The image pickup device or the like including the charge storage electrode of the present invention can have the following form: further including a semiconductor substrate, and

[0188] The photoelectric conversion unit is provided over the semiconductor substrate. Note that the first electrode, the charge accumulation electrode, and the second electrode are connected to a drive circuit described later.

[0189] The second electrode located on the light incident side can be shared by multiple imaging elements. That is, the second electrode can be a so-called solid electrode. The photoelectric conversion layer can be shared by multiple imaging elements. That is, one photoelectric conversion layer can be formed in multiple imaging elements, or can be provided for each imaging element. The composite oxide layer is preferably provided for each imaging element.

[0190] Furthermore, the imaging element or the like of the present invention including the charge accumulation electrode and including the various preferred forms and configurations described above can have a form in which the first electrode extends through an opening formed in the insulating layer to connect to the composite oxide layer. Alternatively, a form in which the composite oxide layer extends through an opening formed in the insulating layer to connect to the first electrode can be adopted. In this case,

[0191] The following form can be adopted: wherein the edge of the top surface of the first electrode is covered by the insulating layer, the first electrode is exposed on the bottom surface of the opening, and

[0192] When the surface of the insulating layer that contacts the top surface of the first electrode is referred to as the first surface, and the surface of the insulating layer that contacts the portion of the composite oxide layer facing the charge storage electrode is referred to as the second surface, the side surface of the opening has an inclination that widens from the first surface toward the second surface. Furthermore, a configuration can be employed in which the side surface of the opening that has an inclination that widens from the first surface toward the second surface is located on the charge storage electrode side.

[0193] Furthermore, the imaging element of the present invention including the charge storage electrode and including the above-mentioned various preferred forms and structures can have the following structure:

[0194] It also includes a control unit, which is provided on the semiconductor substrate and has a drive circuit.

[0195] The first electrode and the charge accumulation electrode are connected to a drive circuit,

[0196] During the charge accumulation period, the drive circuit sets the potential V 11 Applied to the first electrode, the potential V 12 is applied to the charge accumulation electrode, and the charge is accumulated in the composite oxide layer (or the composite oxide layer and the photoelectric conversion layer), and

[0197] During the charge transfer period, the driver circuit sets the potential V 21 Applied to the first electrode, the potential V 22 The charge applied to the charge accumulation electrode and accumulated in the composite oxide layer (or the composite oxide layer and the photoelectric conversion layer) is read out by the control unit via the first electrode. However, when the potential of the first electrode is higher than the potential of the second electrode,

[0198] Meet V 12 ≥V 11 And V 22 <V 21 ,and

[0199] When the potential of the first electrode is lower than the potential of the second electrode, V 12 ≤V 11 And V 22 >V 21 .

[0200] Furthermore, the imaging element, etc., of the present invention, including a charge accumulation electrode and having the various preferred forms and configurations described above, further includes a transfer control electrode (charge transfer electrode), which is disposed separately from the first electrode and the charge accumulation electrode and faces the composite oxide layer via an insulating layer between the first electrode and the charge accumulation electrode. For convenience, the imaging element, etc. of the present invention, including a charge accumulation electrode having such a form, will be referred to as "the imaging element, etc. of the present invention, including a transfer control electrode."

[0201] In addition, the imaging element or the like including the transfer control electrode of the present invention can have the following structure:

[0202] The device further includes a control unit, which is disposed on the semiconductor substrate and has a driving circuit.

[0203] The first electrode, the charge accumulation electrode and the transfer control electrode are connected to a drive circuit,

[0204] During the charge accumulation period, the drive circuit sets the potential V 11 Applied to the first electrode, the potential V12 is applied to the charge accumulation electrode, and the potential V 13 is applied to the transfer control electrode, and the charge is accumulated in the composite oxide layer (or the composite oxide layer and the photoelectric conversion layer), and

[0205] During the charge transfer period, the driver circuit sets the potential V 21 Applied to the first electrode, the potential V 22 is applied to the charge accumulation electrode, and the potential V 23 The charge applied to the transfer control electrode and accumulated in the composite oxide layer (or the composite oxide layer and the photoelectric conversion layer) is read out by the control unit via the first electrode. However, when the potential of the first electrode is higher than the potential of the second electrode,

[0206] Meet V 12 >V 13 And V 22 ≤V 23 ≤V 21 ,and

[0207] When the potential of the first electrode is lower than the potential of the second electrode,

[0208] Meet V 12 <V 13 And V 22 ≥V 23 ≥V 21 .

[0209] In addition, the imaging element etc. having a charge accumulation electrode including the various preferred forms and structures of the present invention can also include a charge discharge electrode, which is connected to the composite oxide layer and is provided separately from the first electrode and the charge accumulation electrode. For convenience, the imaging element etc. of the present invention including a charge accumulation electrode having such a form is referred to as "the imaging element etc. including a charge discharge electrode of the present invention". In addition, the imaging element etc. including a charge discharge electrode of the present invention can have a form in which the charge discharge electrode is provided to surround the first electrode and the charge accumulation electrode (i.e., in a frame shape). The charge discharge electrode can be shared (commonized) by a plurality of imaging elements. In addition, in this case,

[0210] A mode can be adopted in which the complex oxide layer extends in the second opening formed on the insulating layer to be connected to the charge discharge electrode,

[0211] The edge of the top surface of the charge discharge electrode is covered by an insulating layer.

[0212] The charge discharge electrode is exposed on the bottom surface of the second opening, and

[0213] When the surface of the insulating layer in contact with the top surface of the charge discharge electrode is called the third surface, and the surface of the insulating layer in contact with the portion of the composite oxide layer facing the charge accumulation electrode is called the second surface, the side surface of the second opening has an inclination that widens from the third surface toward the second surface.

[0214] Furthermore, the image pickup element or the like including the charge discharge electrode of the present invention can have a configuration in which:

[0215] It also includes a control unit, which is provided on the semiconductor substrate and has a drive circuit.

[0216] The first electrode, the charge accumulation electrode, and the charge discharge electrode are connected to a drive circuit,

[0217] During the charge accumulation period, the drive circuit sets the potential V 11 Applied to the first electrode, the potential V 12 is applied to the charge accumulation electrode, and the potential V 14 is applied to the charge discharge electrode, and the charge is accumulated in the composite oxide layer (or the composite oxide layer and the photoelectric conversion layer), and

[0218] During the charge transfer period, the driver circuit sets the potential V 21 Applied to the first electrode, the potential V 22 is applied to the charge accumulation electrode, and the potential V 24 The charge applied to the charge discharge electrode and accumulated in the composite oxide layer (or the composite oxide layer and the photoelectric conversion layer) is read out by the control unit via the first electrode. However, in the case where the potential of the first electrode is higher than the potential of the second electrode,

[0219] Meet V 14 >V 11 And V 24 <V 21 ,and

[0220] When the potential of the first electrode is lower than the potential of the second electrode,

[0221] Meet V 14 <V 11 And V 24 >V 21 .

[0222] In addition, in the above-mentioned various preferred forms and structures of the imaging element etc. of the present invention including a charge accumulation electrode, the charge accumulation electrode can include a plurality of charge accumulation electrode segments. For the sake of convenience, the imaging element etc. of the present invention including a charge accumulation electrode having such a form is referred to as "the imaging element etc. of the present invention including a plurality of charge accumulation electrode segments". The number of charge accumulation electrode segments only needs to be 2 or more. In addition, the imaging element etc. of the present invention including a plurality of charge accumulation electrode segments can have the following form: wherein,

[0223] When different potentials are applied to N charge accumulation electrode segments,

[0224] In the case where the potential of the first electrode is higher than the potential of the second electrode, in the charge transfer period, the potential applied to the charge accumulation electrode segment closest to the first electrode (the first photoelectric conversion unit segment) is higher than the potential applied to the charge accumulation electrode segment farthest from the first electrode (the Nth photoelectric conversion unit segment), and

[0225] When the potential of the first electrode is lower than the potential of the second electrode, during the charge transfer period, the potential applied to the charge accumulation electrode segment closest to the first electrode (the first photoelectric conversion unit segment) is lower than the potential applied to the charge accumulation electrode segment farthest from the first electrode (the Nth photoelectric conversion unit segment).

[0226] The imaging element having the charge storage electrode and the like of the present invention including the various preferred aspects and structures described above can have the following structure:

[0227] On the semiconductor substrate, at least a floating diffusion layer and an amplifying transistor constituting a control unit are provided, and

[0228] The first electrode is connected to the floating diffusion layer and the gate portion of the amplifying transistor. In addition, in this case,

[0229] The following structure can be adopted:

[0230] A reset transistor and a selection transistor constituting a control unit are further provided on the semiconductor substrate.

[0231] The floating diffusion layer is connected to one source / drain region of the reset transistor, and

[0232] One source / drain region of the amplification transistor is connected to one source / drain region of the selection transistor, and the other source / drain region of the selection transistor is connected to the signal line.

[0233] Furthermore, the imaging element having a charge accumulation electrode and the like of the present invention, including the various preferred forms and configurations described above, can have a form in which the charge accumulation electrode is larger than the first electrode. When the area of ​​the charge accumulation electrode is represented by S1′ and the area of ​​the first electrode is represented by S1,

[0234] Although not limited, it is preferred to satisfy

[0235] 4≤S1' / S1

[0236] Alternatively, examples of variations of the imaging element having a charge accumulation electrode, etc., including the various preferred embodiments of the present invention, include imaging elements having the first to sixth structures described below. That is, in each of the imaging elements having the first to sixth structures among the imaging elements having a charge accumulation electrode, etc., including the various preferred embodiments of the present invention,

[0237] The photoelectric conversion unit includes N (where N≥2) photoelectric conversion unit segments,

[0238] The composite oxide layer and the photoelectric conversion layer include N photoelectric conversion layer segments,

[0239] The insulating layer includes N insulating layer segments,

[0240] In the image pickup elements of the first to third configurations, the charge accumulation electrode includes N charge accumulation electrode segments,

[0241] In the image pickup elements of the fourth and fifth configurations, the charge accumulation electrode includes N charge accumulation electrode segments arranged separately from each other,

[0242] The nth (where n=1, 2, 3, . . . N) photoelectric conversion unit section includes the nth charge accumulation electrode section, the nth insulating layer section, and the nth photoelectric conversion layer section, and

[0243] The larger the n value, the farther the photoelectric conversion unit segment is from the first electrode. Here, the "photoelectric conversion layer segment" refers to a segment formed by stacking a photoelectric conversion layer and a complex oxide layer.

[0244] In addition, in the imaging element of the first configuration, the thickness of the insulating layer segment gradually changes from the first photoelectric conversion unit segment to the Nth photoelectric conversion unit segment. Furthermore, in the imaging element of the second configuration, the thickness of the photoelectric conversion layer segment gradually changes from the first photoelectric conversion unit segment to the Nth photoelectric conversion unit segment. Note that in the photoelectric conversion layer segment, the thickness of the photoelectric conversion layer segment can be changed by changing the thickness of the photoelectric conversion layer portion while keeping the thickness of the composite oxide layer portion constant. Furthermore, the thickness of the photoelectric conversion layer segment can be changed by keeping the thickness of the photoelectric conversion layer portion constant and changing the thickness of the composite oxide layer portion. Furthermore, the thickness of the photoelectric conversion layer segment can be changed by changing the thickness of the photoelectric conversion layer portion and changing the thickness of the composite oxide layer portion. Furthermore, in the imaging element of the third configuration, the materials constituting the insulating layer segment are different for adjacent photoelectric conversion unit segments. Furthermore, in the imaging element of the fourth configuration, the materials constituting the charge accumulation electrode segment are different for adjacent photoelectric conversion unit segments. In addition, in the image pickup element of the fifth configuration, the area of ​​the charge storage electrode section gradually decreases from the first photoelectric conversion unit section to the Nth photoelectric conversion unit section. The area may be reduced continuously or in steps.

[0245] Alternatively, in the imaging element of the sixth configuration, including the imaging elements of the various preferred aspects described above, the stacking direction of the charge storage electrode, the insulating layer, the composite oxide layer, and the photoelectric conversion layer is defined as the Z direction, and the direction of separation from the first electrode is defined as the X direction. When the stacked portion of the charge storage electrode, the insulating layer, the composite oxide layer, and the photoelectric conversion layer is cut along a YZ imaginary plane, the cross-sectional area of ​​the stacked portion changes depending on the distance from the first electrode. The change in cross-sectional area may be continuous or stepwise.

[0246] In the imaging elements of the first and second structures, N photoelectric conversion layer segments are arranged continuously, N insulating layer segments are also arranged continuously, and N charge accumulation electrode segments are also arranged continuously. In the imaging elements of the third to fifth structures, N photoelectric conversion layer segments are arranged continuously. In addition, in the imaging elements of the fourth and fifth structures, N insulating layer segments are arranged continuously. At the same time, in the imaging element of the third structure, N insulating layer segments are arranged to correspond to the corresponding photoelectric conversion unit segments. In addition, in the imaging elements of the fourth and fifth structures, and in some cases in the imaging element of the third structure, N charge accumulation electrode segments are arranged to correspond to the corresponding photoelectric conversion unit segments. In addition, in each of the imaging elements of the first to sixth structures, the same potential is applied to all the charge accumulation electrode segments. Alternatively, in the imaging elements of the fourth and fifth structures, and in some cases in the imaging element of the third structure, different potentials may be applied to the N charge accumulation electrode segments.

[0247] In the imaging element of the present invention including the imaging element of the first to sixth structures, the thickness of the insulating layer segment is limited, or the thickness of the photoelectric conversion layer segment is limited, or the materials constituting the insulating layer segment are different, or the materials constituting the charge accumulation electrode segment are different, or the area of ​​the charge accumulation electrode segment is limited, or the cross-sectional area of ​​the stacked portion is limited. As a result, a charge transfer gradient is formed, and the charge generated by photoelectric conversion can be more easily and reliably transferred to the first electrode. In addition, as a result, the generation of afterimages or transfer residuals can be prevented.

[0248] In the imaging elements of the first to fifth structures, the larger the value of n, the farther the photoelectric conversion unit segment is from the first electrode, but whether the photoelectric conversion unit segment is separated from the first electrode is judged based on the X direction. In addition, in the imaging element of the sixth structure, the direction of separation from the first electrode is defined as the X direction, and the "X direction" is defined as follows. That is, the pixel area in which a plurality of imaging elements or stacked imaging elements are arranged includes pixels regularly arranged in a two-dimensional manner (i.e., in the X direction and the Y direction). In the case where the planar shape of the pixel is a rectangle, the extension direction of the side closest to the first electrode is defined as the Y direction, and the direction orthogonal to the Y direction is defined as the X direction. Alternatively, in the case where the planar shape of the pixel is an arbitrary shape, the overall direction including the line segment or curve closest to the first electrode is defined as the Y direction, and the direction orthogonal to the Y direction is defined as the X direction.

[0249] Hereinafter, regarding the imaging elements of the first to sixth configurations, a case where the potential of the first electrode is higher than the potential of the second electrode will be described.

[0250] In the imaging element of the first configuration, the thickness of the insulating layer section gradually changes from the first photoelectric conversion unit section to the Nth photoelectric conversion unit section. However, the thickness of the insulating layer section preferably gradually increases, thereby forming a charge transfer gradient. In addition, when |V 12 |≥|V 11 | state, the nth photoelectric conversion unit segment can accumulate more charge than the (n+1)th photoelectric conversion unit segment, and a stronger electric field is applied to the nth photoelectric conversion unit segment than the (n+1)th photoelectric conversion unit segment, and the flow of charge from the first photoelectric conversion unit segment to the first electrode can be reliably prevented. In addition, when |V is reached in the charge transfer period 22 |<|V 21| state, the flow of charge from the first photoelectric conversion unit section to the first electrode and the flow of charge from the (n+1)th photoelectric conversion unit section to the nth photoelectric conversion unit section can be reliably ensured.

[0251] In the imaging element of the second configuration, the thickness of the photoelectric conversion layer section gradually changes from the first photoelectric conversion unit section to the Nth photoelectric conversion unit section. However, the thickness of the photoelectric conversion layer section preferably gradually increases, thereby forming a charge transfer gradient. In addition, when |V 12 |≥|V 11 | state, the electric field applied to the nth photoelectric conversion unit segment is stronger than the electric field applied to the (n+1)th photoelectric conversion unit segment, and the flow of charge from the first photoelectric conversion unit segment to the first electrode can be reliably prevented. In addition, when V is reached in the charge transfer period 22 <V 21 , the flow of charge from the first photoelectric conversion unit section to the first electrode and the flow of charge from the (n+1)th photoelectric conversion unit section to the nth photoelectric conversion unit section can be reliably ensured.

[0252] In the imaging element of the third configuration, the materials used to form the insulating layer sections are different for adjacent photoelectric conversion unit sections, thereby forming a charge transfer gradient. Preferably, the dielectric constant value of the material used to form the insulating layer sections gradually decreases from the first photoelectric conversion unit section to the Nth photoelectric conversion unit section. In this case, by adopting this configuration, during the charge accumulation period, when V 12 ≥V 11 , the nth photoelectric conversion unit section can accumulate more charge than the (n+1)th photoelectric conversion unit section. In addition, when V is reached in the charge transfer period 22 <V 21 , the flow of charge from the first photoelectric conversion unit section to the first electrode and the flow of charge from the (n+1)th photoelectric conversion unit section to the nth photoelectric conversion unit section can be reliably ensured.

[0253] In the imaging element of the fourth configuration, the materials used to form the charge accumulation electrode sections differ between adjacent photoelectric conversion cell sections, creating a charge transfer gradient. Preferably, the work function value of the material used to form the insulating layer sections gradually increases from the first photoelectric conversion cell section to the Nth photoelectric conversion cell section. Furthermore, this configuration creates a potential gradient that facilitates signal charge transfer, regardless of whether the voltage is positive or negative.

[0254] In the imaging element of the fifth structure, the area of ​​the charge accumulation electrode section gradually decreases from the first photoelectric conversion unit section to the Nth photoelectric conversion unit section, which forms a charge transfer gradient. Therefore, when V is reached in the charge accumulation period, 12 ≥V 11 In the state of , the nth photoelectric conversion unit segment can store more charge than the (n+1)th photoelectric conversion unit segment. In addition, when V is reached in the charge transfer period 22 <V 21 , the flow of charge from the first photoelectric conversion unit section to the first electrode and the flow of charge from the (n+1)th photoelectric conversion unit section to the nth photoelectric conversion unit section can be reliably ensured.

[0255] In the imaging element of the sixth configuration, the cross-sectional area of ​​the stacked portion depends on the distance from the first electrode, which forms a charge transfer gradient. Specifically, by adopting a configuration in which the thickness of the cross section of the stacked portion is constant and the width of the cross section of the stacked portion becomes narrower as the stacked portion moves away from the first electrode, as described in the imaging element of the fifth configuration, when V is reached during the charge accumulation period, the charge transfer gradient is increased. 12 ≥V 11 When the voltage V is reached during the charge transfer period, the region close to the first electrode can accumulate more charge than the region far from the first electrode. 22 <V 21 , it is possible to reliably ensure the flow of charge from the region close to the first electrode to the first electrode and the flow of charge from the region far from the first electrode to the region close to the first electrode. At the same time, by adopting the following structure: in which the width of the cross section of the stacked portion is constant and the thickness of the cross section of the stacked portion gradually increases, specifically, the thickness of the insulating layer section gradually increases. As described in the imaging element of the first structure, when V is reached during the charge accumulation period, 12 ≥V 11 In the state of , the region close to the first electrode can accumulate more charges than the region far from the first electrode, and a stronger electric field is applied to the region close to the first electrode than to the region far from the first electrode, thereby reliably preventing the flow of charges from the region close to the first electrode to the first electrode. In addition, when V is reached in the charge transfer period 22 <V 21 In the state of V, it is possible to reliably ensure the flow of charge from the region close to the first electrode to the first electrode and the flow of charge from the region far from the first electrode to the region close to the first electrode. In addition, by adopting a structure in which the thickness of the photoelectric conversion layer segment is gradually increased, as described in the imaging element of the second structure, when V is reached during the charge accumulation period, 12 ≥V 11In the state of , a stronger electric field is applied to the region close to the first electrode than to the region far from the first electrode, and the flow of charge from the region close to the first electrode to the first electrode can be reliably prevented. In addition, when V is reached in the charge transfer period 22 <V 21 In the state of , the flow of charge from the region close to the first electrode to the first electrode and the flow of charge from the region far from the first electrode to the region close to the first electrode can be reliably ensured.

[0256] Modifications of the solid-state imaging device according to the first and second aspects of the present invention can be:

[0257] A solid-state imaging device including a plurality of imaging elements of the first to sixth configurations, wherein

[0258] A plurality of imaging elements constitute an imaging element block, and

[0259] The first electrode is shared by a plurality of imaging elements constituting the imaging element block. For convenience, a solid-state imaging device having this configuration is referred to as a "solid-state imaging device having the first configuration." Alternatively, a modified example of the solid-state imaging device according to the first and second aspects of the present invention may be:

[0260] A solid-state imaging device including a plurality of imaging elements of the first to sixth structures or a plurality of stacked imaging elements, each of the plurality of stacked imaging elements including at least one imaging element of the first to sixth structures,

[0261] A plurality of imaging elements or a plurality of stacked imaging elements constitute an imaging element block, and

[0262] The first electrode is shared by the multiple imaging elements or stacked imaging elements that make up the imaging element block. For convenience, a solid-state imaging device having this structure is referred to as a "solid-state imaging device having the second structure." Furthermore, if the first electrode is shared by the multiple imaging elements that make up the imaging element block in this manner, the structure and configuration of the pixel region where the multiple imaging elements are arranged can be simplified and miniaturized.

[0263] In the solid-state imaging devices of the first and second configurations, a floating diffusion layer is provided for a plurality of imaging elements (an imaging element block). The plurality of imaging elements provided for a single floating diffusion layer may be composed of a plurality of first-type imaging elements, described later, or may be composed of at least one first-type imaging element and one or more second-type imaging elements, described later. Furthermore, by appropriately controlling the timing of the charge transfer period, a plurality of imaging elements can share a single floating diffusion layer. The plurality of imaging elements cooperate to be connected to a drive circuit, described later, as an imaging element block. That is, the plurality of imaging elements constituting the imaging element block are connected to a single drive circuit. However, the charge accumulation electrode is controlled for each imaging element. Furthermore, a single contact hole portion can be shared by the plurality of imaging elements. Regarding the arrangement relationship between the first electrode shared by the plurality of imaging elements and the charge accumulation electrodes of the respective imaging elements, there is a case where the first electrode is arranged adjacent to the charge accumulation electrodes of the respective imaging elements. Alternatively, there is a case where the first electrode is arranged adjacent to the charge accumulation electrodes of some of the plurality of imaging elements and not adjacent to the remaining charge accumulation electrodes of the plurality of imaging elements. In this case, charge is transferred from the remaining imaging elements of the plurality of imaging elements to the first electrode via some of the imaging elements. Preferably, the distance between the charge accumulation electrodes of an imaging element (for convenience, referred to as "distance A") is longer than the distance between the first electrode and the charge accumulation electrode of an imaging element adjacent to the first electrode (for convenience, referred to as "distance B") to ensure efficient charge transfer from each imaging element to the first electrode. Furthermore, preferably, the value of distance A increases as the distance between the imaging element and the first electrode increases.

[0264] In addition, the imaging element of the present invention including the various preferred forms and structures described above can have a form in which light is incident from the second electrode side and a light-shielding layer is formed on the light-incident side of the second electrode. Alternatively, a form can be adopted in which light is incident from the second electrode side and the light is not incident on the first electrode (in some cases, not incident on the first electrode and the transfer control electrode). In addition, in this case, a form can be adopted in which a light-shielding layer is formed above the first electrode (in some cases, the first electrode and the transfer control electrode) on the light-incident side of the second electrode. Alternatively, a form can be adopted in which an on-chip microlens is provided above the charge accumulation electrode and the second electrode, and light incident on the on-chip microlens is collected by the charge accumulation electrode. Here, the light-shielding layer can be arranged above the light-incident side surface of the second electrode, or can be arranged on the light-incident side surface of the second electrode. In some cases, a light-shielding layer is formed on the second electrode. Examples of materials constituting the light-shielding layer include chromium (Cr), copper (Cu), aluminum (Al), tungsten (W), and opaque resins (e.g., polyimide resins).

[0265] Specific examples of the imaging element and the like of the present invention include: an imaging element that includes a photoelectric conversion layer or a photoelectric conversion unit that absorbs blue light (light of 425 nm to 495 nm) (for convenience, referred to as a “first-type blue light photoelectric conversion layer” or a “first-type blue light photoelectric conversion unit”) and is sensitive to blue light (for convenience, referred to as a “first-type blue light imaging element”); an imaging element that includes a photoelectric conversion layer or a photoelectric conversion unit that absorbs green light (light of 495 nm to 570 nm) (for convenience, referred to as a “first-type green light photoelectric conversion layer” or a “first-type green light photoelectric conversion unit”) and is sensitive to green light (for convenience, referred to as a “first-type green light imaging element”); and an imaging element that includes a photoelectric conversion layer or a photoelectric conversion unit that absorbs red light (light of 620 nm to 750 nm) (for convenience, referred to as a “first-type red light photoelectric conversion layer” or a “first-type red light photoelectric conversion unit”) and is sensitive to red light (for convenience, referred to as a “first-type red light imaging element”). In addition, for convenience, a conventional imaging element that does not include a charge accumulation electrode and is sensitive to blue light is referred to as a "second type blue light imaging element." For convenience, a conventional imaging element that does not include a charge accumulation electrode and is sensitive to green light is referred to as a "second type green light imaging element." For convenience, a conventional imaging element that does not include a charge accumulation electrode and is sensitive to red light is referred to as a "second type red light imaging element." For convenience, the photoelectric conversion layer or photoelectric conversion unit constituting the second type blue light imaging element is referred to as a "second type blue light photoelectric conversion layer" or a "second type blue light photoelectric conversion unit." For convenience, the photoelectric conversion layer or photoelectric conversion unit constituting the second type green light imaging element is referred to as a "second type green light photoelectric conversion layer" or a "second type green light photoelectric conversion unit." For convenience, the photoelectric conversion layer or photoelectric conversion unit constituting the second type red light imaging element is referred to as a "second type red light photoelectric conversion layer" or a "second type red light photoelectric conversion unit."

[0266] Specific examples of the stacked image pickup element including the charge accumulation electrode include:

[0267] [A] Configuration and structure: wherein the first type blue photoelectric conversion unit, the first type green photoelectric conversion unit, and the first type red photoelectric conversion unit are stacked in a vertical direction, and

[0268] The control unit of the first type blue light imaging element, the control unit of the first type green light imaging element, and the control unit of the first type red light imaging element are all disposed on the semiconductor substrate;

[0269] [B] Configuration and structure: wherein the first-type blue photoelectric conversion unit and the first-type green photoelectric conversion unit are stacked in a vertical direction,

[0270] A second type red light photoelectric conversion unit is arranged below the two first type photoelectric conversion units, and

[0271] The control unit of the first type blue light imaging element, the control unit of the first type green light imaging element, and the control unit of the second type red light imaging element are all disposed on the semiconductor substrate;

[0272] [C] Configuration and structure: wherein the second type blue photoelectric conversion unit and the second type red photoelectric conversion unit are arranged below the first type green photoelectric conversion unit, and

[0273] The control unit of the first type green light imaging element, the control unit of the second type blue light imaging element, and the control unit of the second type red light imaging element are all provided on the semiconductor substrate; and

[0274] [D] Configuration and structure: wherein the second type green photoelectric conversion unit and the second type red photoelectric conversion unit are arranged below the first type blue photoelectric conversion unit, and

[0275] The control unit of the first type blue light imaging element, the control unit of the second type green light imaging element, and the control unit of the second type red light imaging element are all arranged on a semiconductor substrate. Preferably, the arrangement order of the photoelectric conversion units of these imaging elements in the vertical direction is, starting from the light incident direction, a blue light photoelectric conversion unit, a green light photoelectric conversion unit and a red light photoelectric conversion unit, or starting from the light incident direction, a green light photoelectric conversion unit, a blue light photoelectric conversion unit and a red light photoelectric conversion unit. This is because light with shorter wavelengths is more effectively absorbed on the incident surface side. Since red has the longest wavelength of the three colors, it is preferred to position the red light photoelectric conversion unit at the bottom layer when observed from the light incident surface. The stacked structure of these imaging elements constitutes a pixel. In addition, a first type near-infrared photoelectric conversion unit (or infrared photoelectric conversion unit) may be included. Here, preferably, the photoelectric conversion layer of the first type infrared photoelectric conversion unit includes, for example, an organic material and is arranged at the bottom layer of the stacked structure of the first type imaging element located above the second type imaging element. Alternatively, a second-type near-infrared photoelectric conversion unit (or an infrared photoelectric conversion unit) may be provided below the first-type photoelectric conversion unit.

[0276] In the first type imaging element, for example, the first electrode is formed on an interlayer insulating layer provided on a semiconductor substrate. The imaging element formed on the semiconductor substrate may be a back-illuminated type or a front-illuminated type.

[0277] In the case where the photoelectric conversion layer includes an organic material, the photoelectric conversion layer can have any of the following four forms.

[0278] (1) The photoelectric conversion layer is composed of a p-type organic semiconductor.

[0279] (2) The photoelectric conversion layer is composed of an n-type organic semiconductor.

[0280] (3) The photoelectric conversion layer is composed of a stacked structure of a p-type organic semiconductor layer / an n-type organic semiconductor layer. The photoelectric conversion layer is composed of a stacked structure of a p-type organic semiconductor layer / (a mixed layer of a p-type organic semiconductor and an n-type organic semiconductor (bulk heterostructure)) / an n-type organic semiconductor layer. The photoelectric conversion layer is composed of a stacked structure of a p-type organic semiconductor layer / a mixed layer of a p-type organic semiconductor and an n-type organic semiconductor (bulk heterostructure). The photoelectric conversion layer is composed of a stacked structure of an n-type organic semiconductor / a mixed layer of a p-type organic semiconductor and an n-type organic semiconductor (bulk heterostructure).

[0281] (4) The photoelectric conversion layer is composed of a mixed layer (bulk heterostructure) of a p-type organic semiconductor and an n-type organic semiconductor.

[0282] However, the order of stacking can be changed arbitrarily.

[0283] Examples of p-type organic semiconductors include naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, pentacene derivatives, quinacridone derivatives, thiophene derivatives, thienothiophene derivatives, benzothiophene derivatives, benzothiophene-benzothiophene derivatives, triallylamine derivatives, carbazole derivatives, perylene derivatives, chrysene derivatives, Derivatives, fluoranthene derivatives, phthalocyanine derivatives, subphthalocyanine derivatives, subporphyrin derivatives, metal complexes containing heterocyclic compounds as ligands, polythiophene derivatives, polybenzothiadiazole derivatives, and polyfluorene derivatives. Examples of n-type organic semiconductors include fullerenes and fullerene derivatives (e.g., fullerenes such as C60, C70, or C74 (higher fullerenes) or endohedral fullerenes, etc.) or fullerene derivatives (e.g., fullerene fluorides, PCBM fullerene compounds, or fullerene multimers, etc.), organic semiconductors having larger (deeper) HOMO and LUMO than p-type organic semiconductors, and transparent inorganic metal oxides. Specific examples of n-type organic semiconductors include heterocyclic compounds containing nitrogen atoms, oxygen atoms, or sulfur atoms. Examples include: organic molecules and organometallic complexes containing pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, isoquinoline derivatives, acridine derivatives, phenazine derivatives, phenanthroline derivatives, tetrazole derivatives, pyrazole derivatives, imidazole derivatives, thiazole derivatives, oxazole derivatives, imidazole derivatives, benzimidazole derivatives, benzotriazole derivatives, benzoxazole derivatives, benzoxazole derivatives, carbazole derivatives, benzofuran derivatives, dibenzofuran derivatives, porphyrin derivatives, polystyrene derivatives, polybenzothiophene derivatives and polyfluorene derivatives in part of the molecular skeleton, as well as subphthalocyanine derivatives. Examples of the groups and the like contained in the fullerene derivative include: a halogen atom; a linear, branched or cyclic alkyl group or a phenyl group; a group having a linear or condensed aromatic compound; a group including a halide; a partially fluoroalkyl group; a perfluoroalkyl group; a silylalkyl group; a silylalkoxy group; an arylsilyl group; an arylsulfanyl group; an alkylsulfanyl group; an arylsulfonyl group; an alkylsulfonyl group; an arylsulfide group; an alkylsulfide group; an amino group; an alkylamino group; an arylamino group; a hydroxyl group; an alkoxy group; an acylamino group; an acyloxy group; a carbonyl group; a carboxyl group; a carboxamide group; an alkoxycarboxyl group; an acyl group; a sulfonyl group; a cyano group; a nitro group; a group having a chalcogenide compound; a phosphine group; a phosphonic acid group; and derivatives thereof. Although the thickness of the photoelectric conversion layer including an organic material (also referred to as an "organic photoelectric conversion layer") is not limited, the above thickness is, for example, 1×10 -8 m to 5×10 -7 m, preferably 2.5×10 -8 m to 3×10 -7 m, more preferably, 2.5×10 -8 m to 2×10 -7 m, most preferably, 1×10 -7 m to 1.8×10 -7Note that organic semiconductors are generally classified as p-type or n-type. P-type means that they easily transport holes, and n-type means that they easily transport electrons. This is not limited to the following explanation, as in inorganic semiconductors: organic semiconductors have holes or electrons as thermally excited majority carriers.

[0284] Alternatively, examples of materials constituting the organic photoelectric conversion layer that performs photoelectric conversion of green light include rhodamine dyes, merocyanine dyes, quinacridone derivatives, and subphthalocyanine dyes (subphthalocyanine derivatives). Examples of materials constituting the organic photoelectric conversion layer that performs photoelectric conversion of blue light include coumaric acid dyes, tris-8-hydroxyquinoline aluminum (Alq3), and merocyanine dyes. Examples of materials constituting the organic photoelectric conversion layer that performs photoelectric conversion of red light include phthalocyanine dyes and subphthalocyanine dyes (subphthalocyanine derivatives).

[0285] Alternatively, examples of inorganic materials constituting the photoelectric conversion layer include crystalline silicon, amorphous silicon, microcrystalline silicon, crystalline selenium, amorphous selenium, chalcopyrite compounds (e.g., CIGS (CuInGaSe), CIS (CuInSe2), CuInS2, CuAlS2, CuAlSe2, CuGaS2, CuGaSe2, AgAlS2, AgAlSe2, AgInS2, or AgInSe2), Group III-V compounds (e.g., GaAs, InP, AlGaAs, InGaP, AlGaInP, or InGaAsP), and compound semiconductors such as CdSe, CdS, In2Se3, In2S3, Bi2Se3, Bi2S3, ZnSe, ZnS, PbSe, or PbS. In addition, quantum dots comprising these materials can also be used for the photoelectric conversion layer.

[0286] The single-plate color solid-state image pickup device can be constituted by each of the solid-state image pickup devices according to the first and second aspects of the present invention and the solid-state image pickup devices of the first and second configurations.

[0287] In a solid-state imaging device including a stacked imaging element according to the second aspect of the present invention, unlike solid-state imaging devices including imaging elements in a Bayer array (i.e., without using a color filter layer for blue, green, and red color separation), a single pixel is constructed by stacking imaging elements sensitive to multiple wavelengths of light in the same pixel in the direction of light incidence. This improves sensitivity and pixel density per unit volume. Furthermore, because organic materials have a high absorption coefficient, the film thickness of the organic photoelectric conversion layer can be thinner than that of conventional Si-based photoelectric conversion layers, reducing light leakage from adjacent pixels and restrictions on the angle of light incidence. Furthermore, in conventional Si-based imaging elements, false colors are generated by interpolating pixels of three colors to generate color signals. However, the solid-state imaging device including a stacked imaging element according to the second aspect of the present invention can suppress the generation of false colors. The organic photoelectric conversion layer itself also functions as a color filter layer. Therefore, color separation can be performed even without a color filter layer.

[0288] In addition, in the solid-state imaging device according to the first aspect of the present invention, the use of a color filter layer can reduce the requirements for the spectral characteristics of blue, green and red, and large-scale productivity is high. Examples of imaging element arrays in the solid-state imaging device according to the first aspect of the present invention include a Bayer array, an interline array, a G-striped RB square array, a G-striped RB complete square array, a square complementary color array, a stripe array, a diagonal stripe array, a main color difference array, a field color difference sequence array, a frame color difference sequence array, a MOS array, a modified MOS type array, a frame interlaced array and a field interlaced array. Here, one imaging element constitutes one pixel (or sub-pixel).

[0289] In some cases, examples of color filter layers (wavelength selection means) include those that transmit not only red, green, and blue light, but also light having a specific wavelength (e.g., cyan, magenta, or yellow). The color filter layer can be composed not only of an organic material-based color filter layer using an organic compound (e.g., a pigment or dye), but also of a thin film containing an inorganic material such as a photonic crystal, a wavelength selection element using plasmon (a color filter layer having a conductor grid structure having a grid-like hole structure in a conductor thin film, see, for example, Japanese Patent Application Laid-Open No. 2008-177191), or amorphous silicon.

[0290] The pixel region in which multiple imaging elements of the present invention are arranged includes a plurality of pixels regularly arranged in a two-dimensional pattern. The pixel region typically includes an effective pixel region for actually receiving light, amplifying the signal charge generated by photoelectric conversion, and reading the signal charge to a drive circuit; and a black reference pixel region (also known as an optical black pixel region (OPB)) for outputting optical black, which serves as a reference for the black level. The black reference pixel region is typically arranged outside the effective pixel region.

[0291] When the imaging element of the present invention, including the various preferred embodiments and structures described above, is irradiated with light, photoelectric conversion occurs in the photoelectric conversion layer, and carrier separation between holes and electrons occurs. The electrode that extracts holes is referred to as the positive electrode, and the electrode that extracts electrons is referred to as the negative electrode. The first electrode can constitute the negative electrode, and the second electrode can constitute the positive electrode. Conversely, the first electrode can constitute the positive electrode, and the second electrode can constitute the negative electrode.

[0292] The first electrode, the charge accumulation electrode, the transfer control electrode, the charge discharge electrode, and the second electrode can each contain a transparent conductive material. The first electrode, the charge accumulation electrode, the transfer control electrode, and the charge discharge electrode can be collectively referred to as "first electrode, etc.". Alternatively, in the case where the imaging element of the present invention, etc. is arranged in a plane in a manner similar to the Bayer array, for example, the second electrode can contain a transparent conductive material, and the first electrode, etc. can contain a metal material. In this case, specifically, the second electrode located on the light incident side can contain a transparent conductive material, and the first electrode, etc. can contain, for example, Al-Nd (an alloy of aluminum and neodymium) or ASC (an alloy of aluminum, samarium, and copper). The electrode containing a transparent conductive material can be referred to as a "transparent electrode." Here, the band gap energy of the transparent conductive material is above 2.5 eV, preferably above 3.1 eV. Examples of transparent conductive materials constituting the transparent electrode include conductive metal oxides. Specific examples thereof include indium oxide, indium tin oxide (ITO, including In2O3 doped with Sn, crystalline ITO, and amorphous ITO), indium zinc oxide (IZO) obtained by adding indium as a dopant to zinc oxide, indium gallium oxide (IGO) obtained by adding indium as a dopant to gallium oxide, indium-gallium-zinc oxide (IGZO, In-GaZnO4) obtained by adding indium and gallium as dopants to zinc oxide, indium-tin-zinc oxide (ITZO) obtained by adding indium and tin as dopants to zinc oxide, IFO (doped with F-doped In2O3), tin oxide (SnO2), ATO (SnO2 doped with Sb), FTO (SnO2 doped with F), zinc oxide (including ZnO doped with other elements), aluminum zinc oxide (AZO) obtained by adding aluminum as a dopant to zinc oxide, gallium zinc oxide (GZO) obtained by adding gallium as a dopant to zinc oxide, titanium oxide (TiO2), niobium titanium oxide (TNO) obtained by adding niobium as a dopant to titanium oxide, antimony oxide, spinel-type oxides, and oxides having a YbFe2O4 structure. Alternatively, examples of the transparent electrode include a transparent electrode containing gallium oxide, titanium oxide, niobium oxide, nickel oxide, etc. as a base layer. The thickness of the transparent electrode can be 2×10 -8 m to 2×10 - 7 m, preferably 3×10 -8 m to 1×10 -7 m. When the first electrode is required to be transparent, the charge discharge electrode also preferably contains a transparent conductive material from the viewpoint of simplifying the manufacturing process.

[0293] Alternatively, when transparency is not required, the conductive material constituting the positive electrode, which serves as an electrode for extracting holes, is preferably composed of a conductive material having a high work function (e.g., φ = 4.5 eV to 5.5 eV). Specific examples include gold (Au), silver (Ag), chromium (Cr), nickel (Ni), palladium (Pd), platinum (Pt), iron (Fe), iridium (Ir), germanium (Ge), osmium (Os), rhenium (Re), and tellurium (Te). Meanwhile, the conductive material constituting the negative electrode, which serves as an electrode for extracting electrons, is preferably composed of a conductive material having a low work function (e.g., φ = 3.5 eV to 4.5 eV). Specific examples include alkali metals (e.g., Li, Na, or K, etc.), fluorides of alkali metals, oxides of alkali metals, alkaline earth metals (e.g., Mg or Ca, etc.), fluorides of alkaline earth metals, oxides of alkaline earth metals, aluminum (Al), zinc (Zn), tin (Sn), thallium (Tl), sodium-potassium alloys, aluminum-lithium alloys, magnesium-silver alloys, rare earth metals such as indium or ytterbium, and alloys of the above. Alternatively, examples of materials constituting the positive electrode or negative electrode include: metals such as platinum (Pt), gold (Au), palladium (Pd), chromium (Cr), nickel (Ni), aluminum (Al), silver (Ag), tantalum (Ta), tungsten (W), copper (Cu), titanium (Ti), indium (In), tin (Sn), iron (Fe), cobalt (Co), or molybdenum (Mo); alloys containing these metal elements; conductive particles containing these metals; conductive particles containing alloys of these metals; polycrystalline silicon containing impurities; carbon materials; oxide semiconductor materials; and conductive materials such as carbon nanotubes or graphene. A multilayer stacked structure containing these elements can also be used. In addition, examples of materials constituting the positive electrode or negative electrode include organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene-poly(styrenesulfonate)) [PEDOT / PSS]. In addition, these conductive materials can be mixed with a binder (polymer) to form a paste or ink, and the paste or ink can be cured and used as an electrode.

[0294] Dry or wet methods can be used as the method for forming the film of the first electrode etc. or the second electrode (negative electrode or positive electrode).The example of dry method includes physical vapor deposition (PVD method) and chemical vapor deposition (CVD method).The example of the film formed using PVD method principle includes: vacuum vapor deposition method, EB (electron beam) vapor deposition method, various sputtering methods (magnetron sputtering method, RF-DC coupled bias sputtering method, ECR sputtering method, target sputtering method or high frequency sputtering method), ion plating method, laser ablation method, molecular beam epitaxy method and laser transfer method.In addition, the example of CVD method includes: plasma CVD method, thermal CVD method, organometallic (MO) CVD method and optical CVD method.Meanwhile, the example of wet method includes: electroplating method, chemical plating method, spin coating method, inkjet method, spray coating method, imprinting method, micro-contact printing method, flexographic printing method, offset printing method, gravure printing method and impregnation method. Examples of patterning methods include chemical etching such as shadow masking, laser transfer, or photolithography, and physical etching using ultraviolet light, laser, etc. Examples of techniques for planarizing the first electrode, etc., or the second electrode include laser planarization, reflow, and chemical mechanical polishing (CMP).

[0295] Examples of materials constituting the insulating layer include not only inorganic insulating materials represented by metal oxide high dielectric insulating materials such as silicon oxide materials, silicon nitride (SiNY), or aluminum oxide (Al2O3), but also organic insulating materials (organic polymers) represented by linear hydrocarbons having a functional group capable of bonding to a control electrode at one end, such as polymethyl methacrylate (PMMA); polyvinylphenol (PVP); polyvinyl alcohol (PVA); polyimide; polycarbonate (PC); polyethylene terephthalate (PET); polystyrene; silanol derivatives (silane coupling agents) such as N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPTMS), 3-mercaptopropyltrimethoxysilane (MPTMS), or octadecyltrichlorosilane (OTS); novolac phenolic resin; fluorine-based resin; octadecylmercaptan or dodecylisocyanate. Combinations of these can also be used. Examples of silicon oxide materials include silicon oxide (SiO X), BPSG, PSG, BSG, AsSG, PbSG, silicon oxynitride (SiON), SOG (spin-on glass), and low dielectric insulating materials (for example, polyarylether, cyclic fluorocarbon polymers and benzocyclobutene, cyclic fluorocarbon resins, polytetrafluoroethylene, fluorinated aryl ether, fluorinated polyimide, amorphous carbon and organic SOG). The insulating layer can have a single-layer structure, or a structure in which multiple layers (for example, two layers) are stacked. In the latter case, by forming an insulating layer / lower layer at least on the charge accumulation electrode and in the region between the charge accumulation electrode and the first electrode, and flattening the insulating layer / lower layer, it is only necessary to leave the insulating layer / lower layer at least in the region between the charge accumulation electrode and the first electrode, and to form an insulating layer / upper layer only on the remaining insulating layer / lower layer and the charge accumulation electrode. Thus, the flattening of the insulating layer can be reliably achieved. It is only necessary to appropriately select the materials constituting the various interlayer insulating layers and insulating material films from among these materials.

[0296] The configuration and structure of the floating diffusion layer, amplifying transistor, reset transistor and selection transistor constituting the control unit can be the same as those of conventional floating diffusion layers, amplifying transistors, reset transistors and selection transistors. The driving circuit can also have a well-known configuration and structure.

[0297] The first electrode is connected to the floating diffusion layer and the gate portion of the amplifying transistor, and the contact hole portion only needs to be formed to connect the first electrode to the floating diffusion layer and the gate portion of the amplifying transistor. Examples of materials constituting the contact hole portion include: polysilicon doped with impurities; high melting point metals such as tungsten, Ti, Pt, Pd, Cu, TiW, TiN, TiNW, WSi2, or MoSi2; metal silicide; and a stacked structure including layers of these materials (e.g., Ti / TiN / W).

[0298] The first carrier blocking layer may be provided between the composite oxide layer and the first electrode, and the second carrier blocking layer may be provided between the organic photoelectric conversion layer and the second electrode. In addition, the first charge injection layer may be provided between the first carrier blocking layer and the first electrode, and the second charge injection layer may be provided between the second carrier blocking layer and the second electrode. Examples of materials constituting the electron injection layer include; alkali metals, such as lithium (Li), sodium (Na), and potassium (K); alkali metal fluorides; alkali metal oxides; alkaline earth metals, such as magnesium (Mg) or calcium (Ca); alkaline earth metal fluorides; and alkaline earth metal oxides.

[0299] Examples of methods for forming films of various organic layers include dry film formation methods and wet film formation methods. Examples of dry film formation methods include: vacuum vapor deposition using resistance heating, high-frequency heating, or electron beam heating; flash deposition method; plasma vapor deposition method; EB vapor deposition method; various sputtering methods (bipolar sputtering method, DC sputtering method, DC magnetron sputtering method, high-frequency sputtering method, magnetron sputtering method, RF-DC coupled bias sputtering method, ECR sputtering method, target sputtering method, high-frequency sputtering method, and ion beam sputtering method); DC (direct current) method; RF method; multi-cathode method; activation reaction method; electric field vapor deposition method; various ion plating methods (such as high-frequency ion plating method and reactive ion plating method); laser ablation method; molecular beam epitaxy method; laser transfer method; and molecular beam epitaxy (MBE method). In addition, examples of CVD methods include: plasma CVD method, thermal CVD method, MOCVD method, and optical CVD method. Meanwhile, specific examples of wet processes include spin coating, dipping, casting, micro-contact printing, dripping, various printing methods such as screen printing, inkjet printing, offset printing, gravure printing, and flexographic printing, etc., stamping, spraying, and various coating methods such as air knife coater, blade coating, rod coating, knife coating, extrusion coating, reverse roll coating, transfer roll coating, gravure coating, kiss coating, cast coating, spray coating, slit hole coating, and calendar coater. In the coating method, examples of solvents include non-polar or low-polar organic solvents such as toluene, chloroform, hexane, or ethanol. Examples of patterning methods include chemical etching such as shadow mask, laser transfer, or photolithography, and physical etching using ultraviolet rays, lasers, and the like. Examples of techniques for planarizing various organic layers include laser planarization methods and reflow methods.

[0300] Two or more types of imaging elements of the first to sixth configurations described above can be appropriately combined as needed.

[0301] As described above, the imaging element or solid-state imaging device may include an on-chip microlens or a light shielding layer. If necessary, the imaging element or solid-state imaging device may include a drive circuit or wiring for driving the imaging element. If necessary, a shutter for controlling the incidence of light on the imaging element may be provided, or an optical cutoff filter may be provided depending on the purpose of the solid-state imaging device.

[0302] In addition, both the first and second structures of the solid-state imaging device can have a form in which an on-chip microlens is provided above an imaging element of the present invention, or can have a form in which an imaging element block is composed of two imaging elements of the present invention, and an on-chip microlens is provided above the imaging element block.

[0303] For example, in the case of stacking a solid-state imaging device and a readout integrated circuit (ROIC), stacking is performed by stacking a driving substrate on which the readout integrated circuit and a connection portion containing copper (Cu) are formed and an imaging element in which a connection portion is formed, so that the connection portions are in contact with each other and the connection portions are bonded to each other, and the connection portions can be bonded to each other using solder bumps or the like.

[0304] Furthermore, the driving method for driving the solid-state image pickup device according to the first and second aspects of the present invention can be a solid-state image pickup device driving method that repeats the following steps:

[0305] In all imaging elements, while accumulating charges in the composite oxide layer (or the composite oxide layer and the photoelectric conversion layer), all the charges in the first electrode are simultaneously discharged to the outside of the system, and then

[0306] In all imaging elements, all charges accumulated in the composite oxide layer (or the composite oxide layer and the photoelectric conversion layer) are transferred to the first electrode simultaneously, and after the transfer is completed, the charges transferred to the first electrode in each imaging element are sequentially read.

[0307] In this method for driving a solid-state imaging device, each imaging element has a structure in which light incident from the second electrode side does not strike the first electrode. In all imaging elements, while charge is accumulated in the composite oxide layer, etc., all charge in the first electrode is simultaneously discharged to the outside of the system. Therefore, the first electrode can be reliably reset simultaneously in all imaging elements. Furthermore, all charge accumulated in the composite oxide layer, etc., is then simultaneously transferred to the first electrode in all imaging elements. After the transfer is complete, the charge transferred to the first electrode is sequentially read in each imaging element. Thus, a so-called global shutter function can be easily implemented.

[0308] Examples of imaging elements of the present invention include CCD elements, CMOS image sensors, contact image sensors (CIS), and charge modulation device (CMD) amplified image sensors. For example, digital cameras, video cameras, camcorders, surveillance cameras, in-vehicle cameras, smartphone cameras, game user interface cameras, and biometric authentication cameras can be configured using the solid-state imaging devices according to the first and second aspects of the present invention, as well as the solid-state imaging devices of the first and second configurations.

[0309] [Example 1]

[0310] Embodiment 1 relates to the image pickup elements according to the first to third aspects of the present invention, the stacked image pickup element according to the present invention, and the solid-state image pickup device according to the second aspect of the present invention. Figure 1 Schematic partial cross-sectional views of the image pickup element and the stacked image pickup element (hereinafter, they may be collectively referred to as “image pickup element, etc.”) of Example 1 are shown. Figure 2 and Figure 3 An equivalent circuit diagram of the imaging element and the like according to Example 1 is shown. Figure 4 A schematic layout diagram showing a first electrode and a charge storage electrode constituting a photoelectric conversion unit, and a transistor constituting a control unit of the image pickup element and the like according to Example 1. Figure 5 The potential states of various parts during operation of the imaging element and the like according to Example 1 are schematically shown. Figure 6A An equivalent circuit diagram of each portion of the imaging element, etc., for explaining Example 1 is shown. Figure 7 A schematic layout diagram showing a first electrode and a charge storage electrode constituting a photoelectric conversion unit of the image pickup element and the like according to Example 1. Figure 8 A schematic perspective view of a first electrode, a charge accumulation electrode, a second electrode, and a contact hole portion is shown. Figure 76 A conceptual diagram of the solid-state imaging device of Example 1 is shown. Figure 2 、 3 , 6A, 6B, 6C, 9, 17, 18, 29, 30, 66A, 66B and 66C, the composite oxide layer is shown as one layer.

[0311] The imaging element of Example 1 includes a photoelectric conversion unit formed by stacking a first electrode 21, a photoelectric conversion layer 23A, and a second electrode 22. A composite oxide layer 23B is formed between the first electrode 21 and the photoelectric conversion layer 23A. The composite oxide layer 23B includes a first layer 23B1 adjacent to the first electrode 21 and a second layer 23B2 adjacent to the photoelectric conversion layer 23A. Note that the imaging element of Example 1 has a structure in which the first layer 23B1 and the second layer 23B2 are stacked. Furthermore, the composite oxide layer 23B contains an indium composite oxide, and the indium content (indium atomic content) in the first layer 23B1 is higher than the indium content (indium atomic content) in the second layer 23B2. Alternatively, the composite oxide layer 23B comprises an indium-gallium-zinc composite oxide, and the indium content (indium atomic content) in the first layer 23B1 is higher than the indium content (indium atomic content) in the second layer 23B2, or the gallium content (gallium atomic content) in the first layer 23B1 is lower than the gallium content (gallium atomic content) in the second layer 23B2, or the zinc content (zinc atomic content) in the first layer 23B1 is higher than the zinc content (zinc atomic content) in the second layer 23B2. Alternatively, the oxygen atomic content in the first layer 23B1 is lower than the oxygen atomic content in the second layer 23B2. Alternatively, the composite oxide layer 23B comprises an indium composite oxide (or an indium-gallium-zinc composite oxide), and the carrier mobility of the first layer 23B1 is higher than the carrier mobility of the second layer 23B2. Alternatively, the composite oxide layer 23B comprises an indium composite oxide (or an indium-gallium-zinc composite oxide), and the state density of the first layer 23B1 is lower than the state density of the second layer 23B2.

[0312] Here, in the imaging element of Example 1, when the indium-gallium-zinc composite oxide is composed of (ZnO) X (Ga2O3) 1-X 、(Ga2O3) Y (In2O3) 1-Y , and (In2O3) Z (ZnO) 1-Z When indicating,

[0313] The value of X in the first layer 23B1 is greater than the value of X in the second layer 23B2, or

[0314] The Y value in the first layer 23B1 is lower than the Y value in the second layer 23B2, or

[0315] The Z value in the first layer 23B1 is higher than the Z value in the second layer 23B2.

[0316] In addition, in this case, 0 < X < 0.875, 0 < Y < 0.875, and 0.125 < Z < 0.875 are satisfied (where X + Y + Z = 1.000). For the first layer, it is preferable that Y < 0.5. For the second layer, X < 0.5 and Y > 0.5 are satisfied.

[0317] Alternatively, in the imaging element of Example 1 or the like, it is preferable that 1×10 -6 ≤ (carrier mobility of the second layer) / (carrier mobility of the first layer) ≤ 0.1. In addition, the carrier mobility of the first layer is not limited, but it is preferably 10 cm [[ID=[6]] 2 / V·s or more.

[0318] Specific values are as follows:

[0319] In composition in the first layer 23B1: 22%

[0320] In composition in the second layer 23B2: 14%

[0321] X value in the first layer 23B1: 0.4

[0322] X value in the second layer 23B2: 0.25

[0323] Y value in the first layer 23B1: 0.2

[0324] Y value in the second layer 23B2: 0.5

[0325] Z value in the first layer 23B1: 0.4

[0326] Z value in the second layer 23B2: 0.25

[0327] Carrier mobility in the first layer 23B1: 15 cm 2 / V·s

[0328] Carrier mobility in the second layer 23B2: 0.1 cm 2 / V·s

[0329] Note that the thickness of the composite oxide layer 23B is set to 330 nm, and T2 / T1 is set to 10.

[0330] In addition, in the imaging element of Example 1 or the like, according to X-ray diffraction analysis, the composite oxide layer 23B is amorphous. That is, for example, the composite oxide layer 23B is an amorphous state without a local crystal structure.

[0331] In the imaging element of Example 1 and the like, the photoelectric conversion unit further includes an insulating layer 82 and a charge accumulation electrode 24 disposed separately from the first electrode 21 and facing the composite oxide layer 23B via the insulating layer 82. Note that light is incident from the second electrode side.

[0332] The stacked image sensor of Example 1 includes at least one image sensor according to Example 1. Furthermore, the solid-state image sensor device of Example 1 includes a plurality of stacked image sensors according to Example 1. Furthermore, for example, digital cameras, video cameras, video recorders, surveillance cameras, car cameras, smartphone cameras, game user interface cameras, and biometric authentication cameras may all be configured with the solid-state image sensor device of Example 1.

[0333] Hereinafter, the image pickup element and the like and the solid-state image pickup device of Embodiment 1 will be described in detail.

[0334] The imaging element of Example 1 and the like further includes a semiconductor substrate (more specifically, a silicon semiconductor layer) 70, and a photoelectric conversion unit is provided above the semiconductor substrate 70. Furthermore, the imaging element of Example 1 and the like further includes a control unit provided on the semiconductor substrate 70 and having a drive circuit connected to the first electrode 21 and the second electrode 22. Here, the light incident surface of the semiconductor substrate 70 is defined as the upper side, and the opposite side of the semiconductor substrate 70 is defined as the lower side. A wiring layer 62 including a plurality of wirings is provided below the semiconductor substrate 70.

[0335] The semiconductor substrate 70 includes at least a floating diffusion layer FD1 and an amplifier transistor TR1 constituting a control unit. amp , and the first electrode 21 is connected to the floating diffusion layer FD1 and the amplifying transistor TR1 amp The semiconductor substrate 70 further includes a reset transistor TR1 constituting a control unit. rst and select transistor TR1 SEL The floating diffusion layer FD1 is connected to the reset transistor TR1 rst A source / drain region of the amplifier transistor TR1 amp One source / drain region is connected to the select transistor TR1 sel A source / drain region of the selection transistor TR1. sel The other source / drain region of these amplifying transistors TR1 is connected to the signal line VSL1. amp , reset transistor TR1 rst , and select transistor TR1 sel constitute the driving circuit.

[0336] Specifically, the imaging element of Example 1 and the like is a back-illuminated imaging element having a structure formed by stacking three imaging elements: a first-type green imaging element (hereinafter referred to as the "first imaging element") in Example 1, which is sensitive to green light and includes a first-type green photoelectric conversion layer that absorbs green light; a second-type conventional blue imaging element (hereinafter referred to as the "second imaging element"), which is sensitive to blue light and includes a second-type blue photoelectric conversion layer that absorbs blue light; and a second-type conventional red imaging element (hereinafter referred to as the "third imaging element"), which is sensitive to red light and includes a second-type red photoelectric conversion layer that absorbs red light. Here, the red imaging element (third imaging element) and the blue imaging element (second imaging element) are disposed in the semiconductor substrate 70, with the second imaging element being closer to the light incident side than the third imaging element. Furthermore, the green imaging element (first imaging element) is disposed above the blue imaging element (second imaging element). One pixel is composed of a stacked structure of a first imaging element, a second imaging element, and a third imaging element, without a color filter layer.

[0337] In the first imaging element, the first electrode 21 and the charge accumulation electrode 24 are formed on an interlayer insulating layer 81 and separated from each other. The interlayer insulating layer 81 and the charge accumulation electrode 24 are covered by an insulating layer 82. The composite oxide layer 23B and the photoelectric conversion layer 23A are formed on the insulating layer 82, and the second electrode 22 is formed on the photoelectric conversion layer 23A. The insulating layer 83 is formed over the entire surface including the second electrode 22, and the on-chip microlens 14 is provided on the insulating layer 83. The first electrode 21, the charge accumulation electrode 24, and the second electrode 22 are each formed of a transparent electrode containing, for example, ITO (work function: approximately 4.4 eV). The composite oxide layer 23B comprises, for example, IGZO, IWZO, IWO, ZTO, or ITZO. The photoelectric conversion layer 23A is formed of a layer containing a known organic photoelectric conversion material sensitive to at least green light (for example, organic materials such as rhodamine dyes, merocyanine dyes, and quinacridones). The interlayer insulating layer 81 and the insulating layers 82 and 83 each include a known insulating material (e.g., SiO2 or SiN). The composite oxide layer 23B and the first electrode 21 are connected to each other via a connection portion 67 provided in the insulating layer 82. The composite oxide layer 23B extends in the connection portion 67. In other words, the composite oxide layer 23B extends in the opening 85 provided in the insulating layer 82, thereby connecting to the first electrode 21.

[0338] The charge accumulation electrode 24 is connected to the drive circuit. Specifically, the charge accumulation electrode 24 is connected to the drive circuit via the connection hole 66 formed in the interlayer insulating layer 81, the pad portion 64 and the wiring V OA It is connected to the vertical driving circuit 112 constituting the driving circuit.

[0339] The charge accumulation electrode 24 is larger than the first electrode 21. When the area of ​​the charge accumulation electrode 24 is represented by S1′, and the area of ​​the first electrode 21 is represented by S1,

[0340] Although not limited, it is preferred to satisfy

[0341] 4≤S1' / S1.

[0342] In Example 1, for example, although not limited, S1' / S1 is set to 8. Note that in Examples 7 to 10 described later, the sizes of the three photoelectric conversion unit sections 10'1, 10'2, and 10'3 are the same, and their planar shapes are also the same.

[0343] The element isolation region 71 is formed on the first surface (front surface) 70A side of the semiconductor substrate 70. In addition, an oxide film 72 is formed on the first surface 70A of the semiconductor substrate 70. In addition, a reset transistor TR1 constituting a control unit of the first imaging element is provided on the first surface side of the semiconductor substrate 70. rst , Amplifier transistor TR1 amp and select transistor TR1 sel , and a first floating diffusion layer FD1 is also provided.

[0344] Reset transistor TR1 rst The reset transistor TR1 includes a gate portion 51, a channel formation region 51A, and source / drain regions 51B and 51C. rst The gate portion 51 is connected to the reset line RST1. The reset transistor TR1 rst One source / drain region 51C also serves as the first floating diffusion layer FD1, and the other source / drain region 51B is connected to the power supply V DD .

[0345] The first electrode 21 is connected to the reset transistor TR1 via the connection hole 65 and the pad portion 63 formed in the interlayer insulating layer 81, via the contact hole portion 61 formed in the semiconductor substrate 70 and the interlayer insulating layer 76, and via the wiring layer 62 formed on the interlayer insulating layer 76. rst A source / drain region 51C (first floating diffusion layer FD1 ) is formed.

[0346] Amplifier transistor TR1 amp The gate portion 52 includes a gate portion 52, a channel formation region 52A, and source / drain regions 52B and 52C. The gate portion 52 is connected to the first electrode 21 and the reset transistor TR1 through a wiring layer 62. rst One source / drain region 51C (first floating diffusion layer FD1) is connected to the power supply V DD .

[0347] Select transistor TR1 sel The transistor TR1 includes a gate portion 53, a channel forming region 53A, and source / drain regions 53B and 53C. The gate portion 53 is connected to the selection line SEL1. In addition, one source / drain region 53B and a channel forming region 53A constitute the amplifying transistor TR1. amp The other source / drain region 52C shares an area, and the other source / drain region 53C is connected to the signal line (data output line) VSL1 (117).

[0348] The second imaging element includes an n-type semiconductor region 41 as a photoelectric conversion layer provided on a semiconductor substrate 70. The transfer transistor TR2 is a vertical transistor. trs The gate portion 45 extends to the n-type semiconductor region 41, thereby connecting to the transfer gate line TG2. In addition, the second floating diffusion layer FD2 is provided near the transfer transistor TR2 on the semiconductor substrate 70. trs The charge accumulated in the n-type semiconductor region 41 is read out to the second floating diffusion layer FD2 via a transfer path formed along the gate portion 45 .

[0349] In the second imaging element, a reset transistor TR2 constituting a control unit of the second imaging element is further arranged on the first surface side of the semiconductor substrate 70. rst , amplifier transistor TR2 amp and select transistor TR2 sel .

[0350] Reset transistor TR2 rst It includes a gate portion, a channel formation region, and a source / drain region. Reset transistor TR2 rst The gate portion of the reset transistor TR2 is connected to the reset line RST2. rst One source / drain region of is connected to the power supply VDD, and the other source / drain region also functions as a second floating diffusion layer FD2.

[0351] Amplifier transistor TR2 amp It includes a gate portion, a channel formation region, and a source / drain region. The gate portion is connected to the reset transistor TR2. rst Another source / drain region (second floating diffusion layer FD2). In addition, one source / drain region is connected to the power supply V DD .

[0352] Select transistor TR2 sel The transistor TR2 includes a gate portion, a channel forming region, and a source / drain region. The gate portion is connected to the selection line SEL2. In addition, a source / drain region and a transistor TR2 constitute amplification. ampThe region is shared by another source / drain region of VSL, and the other source / drain region is connected to a signal line (data output line) VSL2.

[0353] The third imaging element includes an n-type semiconductor region 43 as a photoelectric conversion layer provided on a semiconductor substrate 70. The transfer transistor TR3 trs The gate portion 46 is connected to the transfer gate line TG3. In addition, the third floating diffusion layer FD3 is provided on the semiconductor substrate 70 near the transfer transistor TR3. trs The charge accumulated in the n-type semiconductor region 43 is read out to the third floating diffusion layer FD3 through a transfer path 46A formed along the gate portion 46 .

[0354] In the third imaging element, the reset transistor TR3 constituting the control unit of the third imaging element rst , amplifier transistor TR3 amp and select transistor TR3 sel It is also provided on the first surface side of the semiconductor substrate 70 .

[0355] Reset transistor TR3 rst It includes a gate portion, a channel formation region, and a source / drain region. Reset transistor TR3 rst The gate portion of the reset transistor TR3 is connected to the reset line RST3. rst One source / drain region is connected to the power supply V DD , and the other source / drain region also functions as a third floating diffusion layer FD3.

[0356] Amplifier transistor TR3 amp It includes a gate portion, a channel formation region, and a source / drain region. The gate portion is connected to the reset transistor TR3. rst Another source / drain region (third floating diffusion layer FD3). In addition, one source / drain region is connected to the power supply V DD .

[0357] Select transistor TR3 sel The transistor TR3 includes a gate portion, a channel forming region, and a source / drain region. The gate portion is connected to the selection line SEL3. In addition, a source / drain region and a channel forming region constitute the amplifier transistor TR3. amp The region is shared by another source / drain region of , and the other source / drain region is connected to a signal line (data output line) VSL3.

[0358] Reset lines RST1, RST2 and RST3, selection lines SEL1, SEL2 and SEL3, and transfer gate lines TG2 and TG3 are connected to the vertical drive circuit 112 constituting the drive circuit, and signal lines (data output lines) VSL1, VSL2 and VSL3 are connected to the column signal processing circuit 113 constituting the drive circuit.

[0359] p + The layer 44 is provided between the n-type semiconductor region 43 and the front surface 70A of the semiconductor substrate 70 in order to suppress the generation of dark current. + The layer 42 is formed between the n-type semiconductor region 41 and the n-type semiconductor region 43. In addition, a part of the side surface of the n-type semiconductor region 43 is formed by the p-type semiconductor region 41. + Layer 42 surrounds. + The layer 73 is formed on the back surface 70B side of the semiconductor substrate 70. The HfO2 film 74 and the insulating material film 75 are formed from the p + The layer 73 extends to a portion where the contact hole 61 is to be formed in the semiconductor substrate 70. Although not shown, wiring is formed in a plurality of layers in the interlayer insulating layer 76.

[0360] The HfO2 film 74 has a negative fixed charge. By forming this film, the generation of dark current can be suppressed. Instead of the HfO2 film, the following films can also be used: aluminum oxide (Al2O3) film, zirconium oxide (ZrO2) film, tantalum oxide (Ta2O5) film, titanium oxide (TiO2) film, lanthanum oxide (La2O3) film, praseodymium oxide (Pr2O3) film, cerium oxide (CeO2) film, neodymium oxide (Nd2O3) film, promethium oxide (Pm2O3) film, samarium oxide (Sm2O3) film. A film, a europium oxide (Eu2O3) film, a gadolinium oxide (Gd2O3) film, a terbium oxide (Tb2O3) film, a dysprosium oxide (Dy2O3) film, a holmium oxide (Ho2O3) film, a thulium oxide (Tm2O3) film, a ytterbium oxide (Yb2O3) film, a lutetium oxide (Lu2O3) film, a yttrium oxide (Y2O3) film, a hafnium nitride film, an aluminum nitride film, a hafnium oxynitride film, or an aluminum oxynitride film. Examples of methods for forming these films include a CVD method, a PVD method, and an ALD method.

[0361] In the following, reference Figure 5 and Figure 6A, the operation of an imaging element including the charge accumulation electrode of Example 1, etc. (first imaging element) will be described. Here, the potential of the first electrode 21 is set to be higher than the potential of the second electrode 22. That is, for example, the first electrode 21 is set to a positive potential, and the second electrode 22 is set to a negative potential. The electrons generated by the photoelectric conversion in the photoelectric conversion layer 23A are read out to the floating diffusion layer. This applies similarly to the other embodiments. Note that in the case where the first electrode 21 is set to a negative potential, the second electrode 22 is set to a positive potential, and the holes generated based on the photoelectric conversion in the photoelectric conversion layer 23A are read out to the floating diffusion layer, it is only necessary to interchange the potential levels described below.

[0362] exist Figure 5 , in Example 4 described later Figure 20 and Figure 21 and in Example 6 Figure 32 and Figure 33 The reference numerals used in the drawings are as follows.

[0363] P A : Point P of the composite oxide layer 23B A The potential at point P A Towards the region between the charge accumulation electrode 24 and the first electrode 21 or between the transfer control electrode (charge transfer electrode) 25 and the first electrode 21

[0364] P B : Point P of the region of the composite oxide layer 23B facing the charge storage electrode 24 B The potential at

[0365] P C1 : Point P of the region of the complex oxide layer 23B facing the charge accumulation electrode segment 24A C1 The potential at

[0366] P C2 : Point P of the region of the complex oxide layer 23B facing the charge storage electrode segment 24B C2 The potential at

[0367] P C3 : Point P of the region of the complex oxide layer 23B facing the charge accumulation electrode segment 24C C3 The potential at

[0368] P D : Point P of the region of the composite oxide layer 23B facing the transfer control electrode (charge transfer electrode) 25 D The potential at

[0369] FD: Potential of the first floating diffusion layer FD1

[0370] V OA: Potential of the charge storage electrode 24

[0371] V OA-A : Potential of the charge accumulation electrode segment 24A

[0372] V OA-B : Potential of charge accumulation electrode segment 24B

[0373] V OA-C : Potential of charge accumulation electrode segment 24C

[0374] V OT : The potential of the transfer control electrode (charge transfer electrode) 25

[0375] RST: reset transistor TR1 rst The potential of the gate portion 51

[0376] V DD : Power supply potential

[0377] VSL1: Signal line (data output line) VSL1

[0378] TR1 rst : Reset transistor TR1 rst

[0379] TR1 amp : Amplifying transistor TR1 amp

[0380] TR1 sel : Select transistor TR1 sel

[0381] During the charge accumulation period, the drive circuit sets the potential V 11 is applied to the first electrode 21, and the potential V 12 The charge storage electrode 24 is applied. The light incident on the photoelectric conversion layer 23A causes photoelectric conversion in the photoelectric conversion layer 23A. The holes generated by the photoelectric conversion are transferred from the second electrode 22 through the wiring V OU At the same time, the potential of the first electrode 21 is set higher than the potential of the second electrode 22, that is, for example, a positive potential is applied to the first electrode 21, and a negative potential is applied to the second electrode 22. Therefore, V 12 ≥V 11 , preferably satisfying V 12 >V 11As a result, the electrons generated by the photoelectric conversion are attracted to the charge accumulation electrode 24, and the electrons stop in the composite oxide layer 23B or in the region of the composite oxide layer 23B and the photoelectric conversion layer 23A (hereinafter, they will be collectively referred to as "the composite oxide layer 23B, etc.") facing the charge accumulation electrode 24. That is, the charge is accumulated in the composite oxide layer 23B, etc. Since V 12 >V 11 Therefore, electrons generated inside the photoelectric conversion layer 23A do not move toward the first electrode 21. During the time of photoelectric conversion, the potential in the region of the complex oxide layer 23B and the like facing the charge storage electrode 24 becomes a more negative value.

[0382] At the latter stage of the charge accumulation period, a reset operation is performed. As a result, the potential of the first floating diffusion layer FD1 is reset, and the potential of the first floating diffusion layer FD1 becomes the potential V of the power supply. DD .

[0383] After the reset operation is completed, the charge is read out. That is, during the charge transfer period, the drive circuit sets the potential V 21 is applied to the first electrode 21, and the potential V 22 is applied to the charge accumulation electrode 24. Here, V 22 <V 21 As a result, the electrons that have stopped in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 are read out to the first electrode 21 and further to the first floating diffusion layer FD1. That is, the charge accumulated in the composite oxide layer 23B and the like is read out to the control unit.

[0384] In this way, a series of operations including charge accumulation, reset operation, and charge transfer are completed.

[0385] After the electrons are read out to the first floating diffusion layer FD1, the amplifying transistor TR1 amp and select transistor TR1 sel The operation of the second and third imaging elements is the same as the conventional operation of these transistors. Furthermore, the series of operations including charge accumulation, reset operation, and charge transfer of the second and third imaging elements is the same as the conventional series of operations including charge accumulation, reset operation, and charge transfer. Furthermore, as in the conventional art, reset noise of the first floating diffusion layer FD1 can be removed through correlated double sampling (CDS) processing.

[0386] As described above, in Example 1, since the charge accumulation electrode is included (the charge accumulation electrode is arranged separately from the first electrode so as to face the photoelectric conversion layer via the insulating layer), when the photoelectric conversion layer is irradiated with light and photoelectrically converted in the photoelectric conversion layer, the composite oxide layer, etc., the insulating layer, and the charge accumulation electrode form a capacitor, and charge can be accumulated in the composite oxide layer, etc. Therefore, at the start of exposure, the charge storage portion can be completely depleted and the charge can be erased. As a result, it is possible to suppress the occurrence of phenomena such as increased kTC noise, deterioration of random noise, and degradation of captured image quality. Furthermore, since all pixels can be reset at once, a so-called global shutter function can be achieved.

[0387] Figure 76 A conceptual diagram of a solid-state imaging device of Example 1 is shown. The solid-state imaging device 100 of Example 1 includes: an imaging area 111, in which stacked imaging elements 101 are arranged in a two-dimensional manner; a vertical driving circuit 112 as a driving circuit (peripheral circuit) of the stacked imaging element 101; a column signal processing circuit 113; a horizontal driving circuit 114, an output circuit 115, a driving control circuit 116, and the like. Needless to say, these circuits can be composed of well-known circuits, and other circuit structures (for example, various circuits used in conventional CCD imaging devices or CMOS imaging devices) can also be used to constitute these circuits. In Figure 76 In FIG. 1 , the reference numeral “ 101 ” of the stacked image sensor 101 is displayed only in one row.

[0388] The drive control circuit 116 generates a clock signal or a control signal based on the vertical synchronization signal, the horizontal synchronization signal, and the main clock, and the clock signal or the control signal serves as a reference for the operation of the vertical drive circuit 112, the column signal processing circuit 113, and the horizontal drive circuit 114. In addition, the generated clock signal or control signal is input to the vertical drive circuit 112, the column signal processing circuit 113, and the horizontal drive circuit 114.

[0389] The vertical drive circuit 112 is composed of, for example, a shift register, and sequentially selects and scans the stacked image pickup elements 101 in the imaging area 111 in the vertical direction in rows. A pixel signal (image signal) based on a current (signal) generated according to the amount of light received by each stacked image pickup element 101 is transmitted to the column signal processing circuit 113 via a signal line (data output line) 117 (VSL).

[0390] For example, a column signal processing circuit 113 is provided for each column of the stacked image sensor 101. For each image sensor, the image signal output from a row of stacked image sensors 101 is subjected to signal processing such as noise reduction or signal amplification using a signal from a black reference pixel (although not shown, formed around the effective pixel area). At the output stage of the column signal processing circuit 113, a horizontal selection switch (not shown) is connected and provided between the column signal processing circuit 113 and the horizontal signal line 118.

[0391] The horizontal driving circuit 114 is configured by, for example, a shift register, and sequentially outputs horizontal scanning pulses to sequentially select the column signal processing circuits 113 and output signals from the column signal processing circuits 113 to the horizontal signal lines 118 .

[0392] The output circuit 115 performs signal processing on the signals sequentially supplied from the column signal processing circuits 113 through the horizontal signal line 118 and outputs the signals.

[0393] Figure 9 An equivalent circuit diagram showing a modified example of the imaging element of Example 1, etc., is shown. Figure 10 A schematic layout diagram of a first electrode, a charge accumulation electrode, and transistors constituting a control unit is shown. The reset transistor TR1 rst The other source / drain region 51B may be grounded instead of connecting the other source / drain region 51B to the power supply V DD .

[0394] For example, the imaging element of Example 1 can be manufactured by the following method. That is, first, an SOI substrate is prepared. Then, a first silicon layer is formed on the surface of the SOI substrate based on an epitaxial growth method, and a p-type silicon layer is formed on the first silicon layer. + Then, a second silicon layer is formed on the first silicon layer based on an epitaxial growth method, and an element separation region 71, an oxide film 72, a p-type semiconductor region 41 are formed on the second silicon layer. + layer 42, n-type semiconductor region 43, and p +Layer 44. In addition, various transistors and the like constituting the control unit of the imaging element are formed on the second silicon layer. A wiring layer 62, an interlayer insulating layer 76 and various wirings are further formed on the second silicon layer, and then the interlayer insulating layer 76 and a supporting substrate (not shown) are bonded together. Subsequently, the SOI substrate is removed to expose the first silicon layer. The surface of the second silicon layer corresponds to the front surface 70A of the semiconductor substrate 70, and the surface of the first silicon layer corresponds to the back surface 70B of the semiconductor substrate 70. In addition, the first silicon layer and the second silicon layer are collectively represented as the semiconductor substrate 70. Subsequently, an opening for forming the contact hole portion 61 is formed on the back surface 70B side of the semiconductor substrate 70, and an HfO2 film 74, an insulating material film 75 and the contact hole portion 61 are formed. Pad portions 63 and 64, an interlayer insulating layer 81, connection holes 65 and 66, a first electrode 21, a charge accumulation electrode 24, and an insulating layer 82 are also formed. Next, the connection portion 67 is opened, and the composite oxide layer 23B, the photoelectric conversion layer 23A, the second electrode 22, the insulating layer 83, and the on-chip microlens 14 are formed. As a result, the image pickup element of Example 1 and the like can be obtained.

[0395] Here, the composite oxide layer 23B is formed as follows: Specifically, the first layer 23B1 is formed by magnetron sputtering or pulsed laser deposition using a target of IGZO (In:Ga:Zn:O=2:1:1:6), and the second layer 23B2 is formed by magnetron sputtering or pulsed laser deposition using a target of IGZO (In:Ga:Zn:O=1:1:1:3).

[0396] In addition, although not shown, the insulating layer 82 can have a two-layer structure including an insulating layer / lower layer and an insulating layer / upper layer. That is, it is only necessary to form the insulating layer / lower layer at least in the region between the charge accumulation electrode 24 and the first electrode 21 (more specifically, it is only necessary to form the insulating layer / lower layer on the interlayer insulating layer 81 including the charge accumulation electrode 24), then flatten the insulating layer / lower layer, and then form the insulating layer / upper layer on the insulating layer / lower layer and the charge accumulation electrode 24. As a result, the insulating layer 82 can be reliably flattened. Then, it is only necessary to open the connection portion 67 in the insulating layer 82 thus obtained.

[0397] In the imaging element of embodiment 1, the composition of each layer is defined in a composite oxide layer having at least two layers, or the relationship between the carrier mobility or state density of each layer is defined in a composite oxide layer having at least two layers. Therefore, when the carriers (for example, photoelectrons) generated by photoelectric conversion flow from the photoelectric conversion layer into the composite oxide layer, carrier stagnation hardly occurs at the interface between the photoelectric conversion layer and the composite oxide layer. As a result, it is possible to provide an imaging element having no adverse effect on the light responsiveness of the imaging element, etc., and having excellent transfer characteristics for the charge accumulated in the photoelectric conversion layer. In addition, the imaging element of embodiment 1, etc. has a two-layer structure of a composite oxide layer and a photoelectric conversion layer. Therefore, recombination during accumulation can be prevented, the transfer efficiency of the charge accumulated in the photoelectric conversion layer to the first electrode can be improved, and the generation of dark current can be suppressed.

[0398] [Example 2]

[0399] Example 2 is a variation of Example 1. Figure 11 The imaging element of Example 2 shown in the schematic partial cross-sectional view is a front-illuminated imaging element, and the above-mentioned imaging element has a structure formed by stacking three imaging elements, namely: the first type green light imaging element (first imaging element) of Example 1, which includes a first type green light photoelectric conversion layer for absorbing green light and is sensitive to green light; the second type conventional blue light imaging element (second imaging element), which includes a second type blue light photoelectric conversion layer for absorbing blue light and is sensitive to blue light; and the second type conventional red light imaging element (third imaging element), which includes a second type red light photoelectric conversion layer for absorbing red light and is sensitive to red light. Here, the red light imaging element (third imaging element) and the blue light imaging element (second imaging element) are arranged in the semiconductor substrate 70, and the second imaging element is closer to the light incident side than the third imaging element. In addition, the green light imaging element (first imaging element) is arranged above the blue light imaging element (second imaging element).

[0400] As in Embodiment 1, various transistors constituting the control unit are provided on the front surface 70A side of the semiconductor substrate 70. The transistors can have substantially the same configuration and structure as the transistors described in Embodiment 1. Furthermore, the semiconductor substrate 70 includes a second imaging element and a third imaging element, and these imaging elements can have substantially the same configuration and structure as the second imaging element and the third imaging element described in Embodiment 1.

[0401] An interlayer insulating layer 81 is formed above the front surface 70A of the semiconductor substrate 70. Above the interlayer insulating layer 81, a photoelectric conversion unit (first electrode 21, composite oxide layer 23B, photoelectric conversion layer 23A, second electrode 22, charge accumulation electrode 24, etc.) including a charge accumulation electrode and constituting the imaging element of Example 1 is provided.

[0402] In this manner, except that the imaging element of Example 2 is a front-illuminated type, the configuration and structure of the imaging element etc. of Example 2 can be the same as those of Example 1. Therefore, detailed description thereof is omitted.

[0403] [Example 3]

[0404] Example 3 is a variation of Example 1 and Example 2.

[0405] Figure 12 The imaging element of Example 3 shown in the schematic partial cross-sectional view is a back-illuminated imaging element, and the imaging element has a structure formed by stacking two imaging elements of the first type first imaging element and the second type second imaging element of Example 1. In addition, Figure 13 A modified example of the imaging element of Example 3, shown in the schematic partial cross-sectional view, is a front-illuminated imaging element having a structure formed by stacking two imaging elements: the first imaging element of the first type and the second imaging element of the second type. Here, the first imaging element absorbs primary color light, while the second imaging element absorbs complementary color light. Alternatively, the first imaging element absorbs white light, while the second imaging element absorbs infrared light.

[0406] Figure 14 The modified example of the imaging element of Example 3 shown in the schematic partial cross-sectional view is a back-illuminated imaging element and is composed of the first type first imaging element of Example 1. In addition, Figure 15 A modified example of the imaging element of Example 3 shown in the schematic partial cross-sectional view is a front-illuminated imaging element, and is composed of the first type of first imaging element of Example 1. Here, the first imaging element is composed of three types of imaging elements: an imaging element for absorbing red light; an imaging element for absorbing green light; and an imaging element for absorbing blue light. In addition, the solid-state imaging device according to the first aspect of the present invention is composed of a plurality of the above-mentioned imaging elements. A Bayer array can be cited as the arrangement of the plurality of imaging elements. On the light incident side of each imaging element, a color filter layer for separating blue, green, and red is provided as needed.

[0407] Instead of providing a single first-type photoelectric conversion unit including the charge accumulation electrode of Example 1, a configuration in which two first-type photoelectric conversion units are stacked (i.e., two photoelectric conversion units each including a charge accumulation electrode are stacked, and control units for the two photoelectric conversion units are provided on a semiconductor substrate) or a configuration in which three first-type photoelectric conversion units are stacked (i.e., three photoelectric conversion units each including a charge accumulation electrode are stacked, and control units for the three photoelectric conversion units are provided on a semiconductor substrate) can be employed. The table below shows an example of a stacked structure of a first-type imaging element and a second-type imaging element.

[0408]

[0409] [Example 4]

[0410] Embodiment 4 is a modification of Embodiments 1 to 3, and relates to an image pickup element or the like including a transfer control electrode (charge transfer electrode) of the present invention. Figure 16 A schematic partial cross-sectional view showing a portion of the image pickup element and the like according to Example 4. Figure 17 and Figure 18 An equivalent circuit diagram of an imaging element and the like according to Example 4 is shown. Figure 19 A schematic layout diagram showing a first electrode, a transfer control electrode, and a charge accumulation electrode constituting a photoelectric conversion unit, and a transistor constituting a control unit constituting the image pickup element and the like of Example 4. Figure 20 and Figure 21 The potential states of various parts during operation of the imaging element of Example 4 are schematically shown. Figure 6B An equivalent circuit diagram of each portion of the imaging element, etc., for explaining Example 4 is shown. Figure 22 A schematic layout diagram showing a first electrode, a transfer control electrode, and a charge accumulation electrode constituting a photoelectric conversion unit of an image pickup element and the like according to Example 4. Figure 23 A schematic perspective view of a first electrode, a transfer control electrode, a charge accumulation electrode, a second electrode, and a contact hole portion is shown.

[0411] The imaging element of Example 4 further includes a transfer control electrode (charge transfer electrode) 25, which is located between the first electrode 21 and the charge accumulation electrode 24, is arranged separately from the first electrode 21 and the charge accumulation electrode 24, and faces the composite oxide layer 23B via the insulating layer 82. The transfer control electrode 25 is connected to the composite oxide layer 23B via the connection hole 68B formed in the interlayer insulating layer 81, the pad portion 68A, and the wiring V OT Note that, to simplify the drawing, various imaging element components located below the interlayer insulating layer 81 are collectively denoted by reference numeral 13 for convenience.

[0412] In the following, reference Figure 20 and Figure 21 , the operation of the imaging element etc. (first imaging element) of Example 4 will be described. Note that for Figure 20 and Figure 21 , the potential value applied to the charge accumulation electrode 24 and the point P D The potential values ​​at are particularly different.

[0413] During the charge accumulation period, the drive circuit sets the potential V 11 Applied to the first electrode 21, the potential V 12 is applied to the charge accumulation electrode 24, and the potential V 13 is applied to the transfer control electrode 25. By the light incident on the photoelectric conversion layer 23A, photoelectric conversion occurs in the photoelectric conversion layer 23A. The holes generated by the photoelectric conversion pass through the wiring V OU From the second electrode 22 to the driving circuit. At the same time, the potential of the first electrode 21 is set higher than the potential of the second electrode 22, that is, for example, a positive potential is applied to the first electrode 21, and a negative potential is applied to the second electrode 22. Therefore, V 12 >V 13 (For example, V 12 >V 11 >V 13 or V 11 >V 12 >V 13 ). As a result, the electrons generated by the photoelectric conversion are attracted to the charge accumulation electrode 24, and the electrons stop in the region of the composite oxide layer 23B etc. facing the charge accumulation electrode 24. That is, the charge is accumulated in the composite oxide layer 23B etc. Since V 12 >V 13 Therefore, electrons generated inside the photoelectric conversion layer 23A can be reliably prevented from moving toward the first electrode 21. As time passes for photoelectric conversion, the potential in the region of the composite oxide layer 23B and the like facing the charge storage electrode 24 becomes more negative.

[0414] At the latter stage of the charge accumulation period, a reset operation is performed. As a result, the potential of the first floating diffusion layer FD1 is reset, and the potential of the first floating diffusion layer FD1 becomes the potential V of the power supply. DD .

[0415] After the reset operation is completed, the charge is read out. That is, during the charge transfer period, the drive circuit sets the potential V 21 Applied to the first electrode 21, the potential V 22 is applied to the charge accumulation electrode 24, and the potential V 23 is applied to the transmission control electrode 25. Here, V22 ≤V 23 ≤V 21 (Preferably, V 22 <V 23 <V 21 ). When the potential V 13 When applied to the transmission control electrode 25, it is only necessary to satisfy V 22 ≤V 13 ≤V 21 (Preferably, V 22 <V 13 <V 21 As a result, the electrons stopped in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 are reliably read out to the first electrode 21 and further to the first floating diffusion layer FD1. That is, the charge accumulated in the composite oxide layer 23B and the like is read out to the control unit.

[0416] In this way, a series of operations including charge accumulation, reset operation, and charge transfer are completed.

[0417] After the electrons are read out to the first floating diffusion layer FD1, the amplifying transistor TR1 amp and select transistor TR1 sel The operation is the same as the normal operation of these transistors. In addition, for example, a series of operations including charge accumulation, reset operation and charge transfer of the second imaging element and the third imaging element is the same as a series of operations including charge accumulation, reset operation and charge transfer of the normal imaging element.

[0418] Figure 24 A schematic layout diagram showing a first electrode and a charge storage electrode constituting a modification of the imaging element of Example 4 and transistors constituting a control unit, a reset transistor TR1 and a reset transistor TR2. rst The other source / drain region 51B may be grounded instead of connecting the other source / drain region 51B to the power supply V DD .

[0419] [Example 5]

[0420] Embodiment 5 is a modification of Embodiments 1 to 4 and relates to an image pickup element or the like of the present invention including a charge discharge electrode. Figure 25 A schematic partial cross-sectional view showing a portion of the image pickup element and the like according to Example 5. Figure 26 A schematic layout diagram showing a first electrode, a charge accumulation electrode, and a charge discharge electrode constituting a photoelectric conversion unit including a charge accumulation electrode of an image pickup element or the like according to Example 5. Figure 27 A schematic perspective view of a first electrode, a charge accumulation electrode, a charge discharge electrode, a second electrode, and a contact hole portion is shown.

[0421] The imaging element of Example 5 and the like further includes a charge discharge electrode 26, which is connected to the composite oxide layer 23B via a connection portion 69, and the charge discharge electrode 26 is arranged separately from the first electrode 21 and the charge accumulation electrode 24. Here, the charge discharge electrode 26 is arranged so as to surround the first electrode 21 and the charge accumulation electrode 24 (i.e., in a frame shape). The charge discharge electrode 26 is connected to the pixel drive circuit constituting the drive circuit. The composite oxide layer 23B extends in the connection portion 69. That is, the composite oxide layer 23B extends in the second opening portion 86 formed in the insulating layer 82, thereby connecting to the charge discharge electrode 26. The charge discharge electrode 26 is shared (shared) by a plurality of imaging elements.

[0422] In Embodiment 5, during the charge accumulation period, the drive circuit sets the potential V 11 Applied to the first electrode 21, the potential V 12 is applied to the charge accumulation electrode 24, and the potential V 14 The charge is applied to the charge discharge electrode 26, and the charge is accumulated in the composite oxide layer 23B and the like. By the light incident on the photoelectric conversion layer 23A, photoelectric conversion occurs in the photoelectric conversion layer 23A. The holes generated by the photoelectric conversion pass through the wiring V OU From the second electrode 22 to the driving circuit. At the same time, the potential of the first electrode 21 is set higher than the potential of the second electrode 22, that is, for example, a positive potential is applied to the first electrode 21, and a negative potential is applied to the second electrode 22. Therefore, V 14 >V 11 (For example, V 12 >V 14 >V 11 ). As a result, the electrons generated by the photoelectric conversion are attracted to the charge accumulation electrode 24, and the electrons stop in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24. This can reliably prevent the electrons from being transported toward the first electrode 21. However, electrons that are not sufficiently attracted to the charge accumulation electrode 24 or electrons that cannot be accumulated in the composite oxide layer 23B and the like (so-called overflow electrons) are sent to the drive circuit via the charge discharge electrode 26.

[0423] At the latter stage of the charge accumulation period, a reset operation is performed. As a result, the potential of the first floating diffusion layer FD1 is reset, and the potential of the first floating diffusion layer FD1 becomes the potential V of the power supply. DD .

[0424] After the reset operation is completed, the charge is read out. That is, during the charge transfer period, the drive circuit sets the potential V 21 Applied to the first electrode 21, the potential V 22is applied to the charge accumulation electrode 24, and the potential V 24 is applied to the charge discharge electrode 26. Here, V 24 <V 21 (For example, V 24 <V 22 <V 21 As a result, electrons stopped in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 are reliably read out to the first electrode 21 and further to the first floating diffusion layer FD1. That is, the charge accumulated in the composite oxide layer 23B and the like is read out to the control unit.

[0425] In this way, a series of operations including charge accumulation, reset operation, and charge transfer are completed.

[0426] After the electrons are read out to the first floating diffusion layer FD1, the amplifying transistor TR1 amp and select transistor TR1 sel The operation is the same as the normal operation of these transistors. In addition, for example, a series of operations including charge accumulation, reset operation and charge transfer of the second imaging element and the third imaging element is the same as a series of operations including charge accumulation, reset operation and charge transfer of the normal imaging element.

[0427] In Example 5, so-called overflow electrons are sent to the drive circuit via the charge discharge electrode 26. This prevents charge from leaking to the charge accumulation portion of adjacent pixels, and also suppresses the occurrence of blooming. This also improves the imaging performance of the imaging element.

[0428] [Example 6]

[0429] Embodiment 6 is a modification of Embodiment 1 to Embodiment 5, and relates to an image pickup element or the like of the present invention including a plurality of charge accumulation electrode segments.

[0430] Figure 28 A schematic partial cross-sectional view showing a portion of the imaging element and the like according to Example 6. Figure 29 and Figure 30 An equivalent circuit diagram of an imaging element and the like according to Example 6 is shown. Figure 31 A schematic layout diagram showing the configuration of an image pickup element or the like according to Example 6, including a first electrode and a charge accumulation electrode of a photoelectric conversion unit including a charge accumulation electrode, and transistors constituting a control unit. Figure 32 and Figure 33 The potential states of various parts during operation of the imaging element and the like according to Example 6 are schematically shown. Figure 6C An equivalent circuit diagram of each portion of the imaging element, etc., for explaining Example 6 is shown. Figure 34A schematic layout diagram showing a first electrode and a charge storage electrode constituting a photoelectric conversion unit including a charge storage electrode in an image pickup element or the like according to Example 6. Figure 35 A schematic perspective view of a first electrode, a charge accumulation electrode, a second electrode, and a contact hole portion is shown.

[0431] In Example 6, the charge accumulation electrode 24 includes a plurality of charge accumulation electrode segments 24A, 24B, and 24C. The number of charge accumulation electrode segments need only be two or more, and in Example 6, this number is set to "3." Furthermore, in the imaging element and the like of Example 6, the potential of the first electrode 21 is higher than that of the second electrode 22. Therefore, for example, a positive potential is applied to the first electrode 21, and a negative potential is applied to the second electrode 22. Furthermore, during the charge transfer period, the potential applied to the charge accumulation electrode segment 24A located closest to the first electrode 21 is higher than the potential applied to the charge accumulation electrode segment 24C located farthest from the first electrode 21. In this way, by applying a potential gradient to the charge accumulation electrode 24, electrons that have stopped in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 are more reliably read out to the first electrode 21 and, further, to the first floating diffusion layer FD1. In other words, the charge accumulated in the composite oxide layer 23B and the like is read out to the control unit.

[0432] exist Figure 32 In the example shown, in the charge transfer period, since the potential of the charge accumulation electrode segment 24C < the potential of the charge accumulation electrode segment 24B < the potential of the charge accumulation electrode segment 24A is satisfied, the electrons that have stopped in the region of the composite oxide layer 23B and the like are all read out to the first floating diffusion layer FD1 at once. Figure 33 In the example shown, during the charge transfer period, by gradually changing the potential of the charge accumulation electrode segment 24C, the potential of the charge accumulation electrode segment 24B, and the potential of the charge accumulation electrode segment 24A (i.e., by changing the potential of the charge accumulation electrode segment 24C, the potential of the charge accumulation electrode segment 24B, and the potential of the charge accumulation electrode segment 24A in a stepwise or ramped manner), electrons that have stopped in the region of the composite oxide layer 23B or the like facing the charge accumulation electrode segment 24C are transferred to the region of the composite oxide layer 23B or the like facing the charge accumulation electrode segment 24B. Subsequently, electrons that have stopped in the region of the composite oxide layer 23B or the like facing the charge accumulation electrode segment 24B are transferred to the region of the composite oxide layer 23B or the like facing the charge accumulation electrode segment 24A. Subsequently, the electrons that have stopped in the region of the composite oxide layer 23B or the like facing the charge accumulation electrode segment 24A are reliably read out to the first floating diffusion layer FD1.

[0433] Figure 36A schematic layout diagram showing a first electrode and a charge storage electrode constituting a modification of the imaging element of Example 6 and transistors constituting a control unit, a reset transistor TR1 and a reset transistor TR2. rst The other source / drain region 51B may be grounded instead of being connected to the power supply V DD .

[0434] [Example 7]

[0435] Example 7 is a modification of Example 1 to Example 6, and relates to the image pickup elements of the first and sixth configurations.

[0436] Figure 37 A schematic partial cross-sectional view showing an image pickup element and the like according to Example 7. Figure 38 A schematic partial cross-sectional view obtained by enlarging a portion where a charge storage electrode, a complex oxide layer, a photoelectric conversion layer, and a second electrode are stacked is shown. Figure 2 and Figure 3 The equivalent circuit diagram of the imaging element of Example 1 described in is the same as that of the first embodiment. The schematic layout diagram of the first electrode and the charge accumulation electrode of the photoelectric conversion unit including the charge accumulation electrode and the transistor constituting the control unit constituting the imaging element of Example 7 is the same as that of the first embodiment. Figure 4 The operation of the imaging element and the like of the embodiment 7 (first imaging element) is basically the same as that of the imaging element and the like of the embodiment 1.

[0437] Here, in the imaging element of Example 7 or the imaging elements of Examples 8 to 12 described later,

[0438] The photoelectric conversion unit includes N (where N≧2) photoelectric conversion unit sections (specifically, three photoelectric conversion unit sections 10 ′ 1 , 10 ′ 2 and 10 ′ 3 ),

[0439] The complex oxide layer 23B and the photoelectric conversion layer 23A include N photoelectric conversion layer segments (specifically, three photoelectric conversion layer segments 23 ′ 1 , 23 ′ 2 , and 23 ′ 3 ),

[0440] The insulating layer 82 includes N insulating layer segments (specifically, three insulating layer segments 82 ′ 1 , 82 ′ 2 , and 82 ′ 3 ).

[0441] In Embodiments 7 to 9, the charge accumulation electrode 24 includes N charge accumulation electrode segments (specifically, three charge accumulation electrode segments 24'1, 24'2, and 24'3 in each embodiment),

[0442] In Examples 10 and 11, in some cases, in Example 9, the charge accumulation electrode 24 includes N charge accumulation electrode segments (specifically, three charge accumulation electrode segments 24'1, 24'2, and 24'3) arranged apart from each other,

[0443] nth (where n=1, 2, 3 . . . N) photoelectric conversion unit section 10 ′ n Including the nth charge accumulation electrode segment 24' n , nth insulating layer segment 82' n , and the nth photoelectric conversion layer segment 23 ' n ,and

[0444] The photoelectric conversion unit segment with a larger n value is farther from the first electrode 21. Here, the photoelectric conversion layer segments 23'1, 23'2, and 23'3 represent segments formed by stacking a composite oxide layer and a photoelectric conversion layer, and in the drawings, to simplify the drawings, these segments are represented by a single layer. This also applies to the following description.

[0445] Note that in the photoelectric conversion layer segment, the thickness of the photoelectric conversion layer segment can be changed by changing the thickness of the photoelectric conversion layer portion while keeping the thickness of the composite oxide layer portion constant. Furthermore, the thickness of the photoelectric conversion layer segment can be changed by keeping the thickness of the photoelectric conversion layer portion constant and changing the thickness of the composite oxide layer portion. Furthermore, the thickness of the photoelectric conversion layer segment can be changed by changing the thickness of both the photoelectric conversion layer portion and the composite oxide layer portion.

[0446] Alternatively, the image pickup element of Example 7 or the image pickup elements of Examples 8 and 11 described later may include:

[0447] The photoelectric conversion unit is formed by stacking the first electrode 21 , the complex oxide layer 23B, the photoelectric conversion layer 23A, and the second electrode 22 .

[0448] The photoelectric conversion unit also includes a charge accumulation electrode 24 that is arranged separately from the first electrode 21 and faces the complex oxide layer 23B via the insulating layer 82 .

[0449] If the stacking direction of the charge accumulation electrode 24, the insulating layer 82, the composite oxide layer 23B and the photoelectric conversion layer 23A is defined as the Z direction, and the direction of separation from the first electrode 21 is defined as the X direction, then when the stacking portion where the charge accumulation electrode 24, the insulating layer 82, the composite oxide layer 23B and the photoelectric conversion layer 23A are stacked is cut with a YZ imaginary plane, the cross-sectional area of ​​the stacking portion varies depending on the distance from the first electrode.

[0450] In the imaging element of Example 7, the thickness of the insulating layer section is from the first photoelectric conversion unit section 10'1 to the Nth photoelectric conversion unit section 10'1. N Gradually changes. Specifically, the thickness of the insulating layer segment gradually increases. Alternatively, in the imaging element of Example 7, etc., the width of the cross section of the stacked portion is constant, and the thickness of the cross section of the stacked portion, specifically, the thickness of the insulating layer segment gradually increases depending on the distance from the first electrode 21. Note that the thickness of the insulating layer segment increases in a stepwise manner. The nth photoelectric conversion unit segment 10' n Insulation layer section 82' n The thickness is constant. When the nth photoelectric conversion unit segment 10' n Insulation layer section 82' n When the thickness is "1", the (n+1)th photoelectric conversion unit segment 10' (n+1) Insulation layer section 82' (n+1) Examples of the thickness include 2 to 10, but are not limited to these values. In Example 7, the thickness of the insulating layer segments 82'1, 82'2, and 82'3 is gradually increased by gradually reducing the thickness of the charge accumulation electrode segments 24'1, 24'2, and 24'3. The thickness of the photoelectric conversion layer segments 23'1, 23'2, and 23'3 is constant.

[0451] Hereinafter, the operation of the image pickup element and the like of Embodiment 7 will be described.

[0452] During the charge accumulation period, the drive circuit sets the potential V 11 is applied to the first electrode 21, and the potential V 12 The charge storage electrode 24 is applied. By the light incident on the photoelectric conversion layer 23A, photoelectric conversion occurs in the photoelectric conversion layer 23A. The holes generated by the photoelectric conversion are transferred from the second electrode 22 through the wiring V OU At the same time, the potential of the first electrode 21 is set higher than the potential of the second electrode 22, that is, for example, a positive potential is applied to the first electrode 21 and a negative potential is applied to the second electrode 22. Therefore, V 12 ≥V 11 , preferably, satisfying V 12 >V 11 As a result, electrons generated by photoelectric conversion are attracted to the charge accumulation electrode 24, and the electrons stop in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24. That is, charges are accumulated in the composite oxide layer 23B and the like. 12 >V 11Therefore, electrons generated inside the photoelectric conversion layer 23A do not move toward the first electrode 21. During the time of photoelectric conversion, the potential in the region of the complex oxide layer 23B and the like facing the charge storage electrode 24 becomes a more negative value.

[0453] In the image pickup element of Example 7 and the like, a configuration is adopted in which the thickness of the insulating layer section gradually increases. Therefore, when |V 12 |≥|V 11 | state, the nth photoelectric conversion unit segment 10 ' n The accumulation of the (n+1)th photoelectric conversion unit section 10' is possible (n+1) More charges are sent to the nth photoelectric conversion unit section 10' n Towards the (n+1)th photoelectric conversion unit section 10' (n+1) A stronger electric field is applied, and the charge can be reliably prevented from flowing from the first photoelectric conversion unit section 10 ′ 1 to the first electrode 21 .

[0454] At the latter stage of the charge accumulation period, a reset operation is performed. As a result, the potential of the first floating diffusion layer FD1 is reset, and the potential of the first floating diffusion layer FD1 becomes the potential V of the power supply. DD .

[0455] After the reset operation is completed, the charge is read out. That is, during the charge transfer period, the drive circuit sets the potential V 21 is applied to the first electrode 21, and the potential V 22 is applied to the charge accumulation electrode 24. Here, V 21 >V 22 As a result, electrons stopped in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 are read out to the first electrode 21 and further to the first floating diffusion layer FD1. That is, the charge accumulated in the composite oxide layer 23B and the like is read out to the control unit.

[0456] More specifically, when V 21 >V 22 When the state is set, it is possible to reliably ensure that the charge flows from the first photoelectric conversion unit segment 10'1 to the first electrode 21 and ensure that the charge flows from the (n+1)th photoelectric conversion unit segment 10' (n+1) Flows to the nth photoelectric conversion unit section 10' n .

[0457] In this way, a series of operations including charge accumulation, reset operation, and charge transfer are completed.

[0458] In the imaging element of Example 7 and other embodiments, the thickness of the insulating layer section gradually changes from the first photoelectric conversion unit section to the Nth photoelectric conversion unit section. Alternatively, when the stacked portion comprising the charge accumulation electrode, insulating layer, composite oxide layer, and photoelectric conversion layer is cut along a YZ imaginary plane, the cross-sectional area of ​​the stacked portion varies depending on the distance from the first electrode. This creates a charge transfer gradient, enabling easier and more reliable transfer of charge generated by photoelectric conversion.

[0459] Since the imaging element and the like of Example 7 can be manufactured by a method basically similar to that of the imaging element and the like of Example 1, detailed description thereof will be omitted.

[0460] Note that in the imaging element of Example 7 and the like, when forming the first electrode 21, the charge accumulation electrode 24, and the insulating layer 82, a conductive material layer for forming the charge accumulation electrode 24'3 is first formed on the interlayer insulating layer 81. The conductive material layer is patterned to leave the conductive material layer in the regions where the photoelectric conversion unit segments 10'1, 10'2, and 10'3 and the first electrode 21 will be formed. This results in a portion of the first electrode 21 and the charge accumulation electrode 24'3. Next, an insulating layer for forming the insulating layer segment 82'3 is formed over the entire surface. The insulating layer is patterned and flattened to form the insulating layer segment 82'3. Next, a conductive material layer for forming the charge accumulation electrode 24'2 is formed over the entire surface. The conductive material layer is patterned to leave the conductive material layer in the regions where the photoelectric conversion unit segments 10'1 and 10'2 and the first electrode 21 will be formed. This results in a portion of the first electrode 21 and the charge accumulation electrode 24'2. Next, an insulating layer for forming the insulating layer segment 82'2 is formed on the entire surface. The insulating layer is patterned and flattened to obtain the insulating layer segment 82'2. Next, a conductive material layer for forming the charge accumulation electrode 24'1 is formed on the entire surface. The conductive material layer is patterned, and the conductive material layer is left in the area where the photoelectric conversion unit segment 10'1 and the first electrode 21 will be formed. Thus, the first electrode 21 and the charge accumulation electrode 24'1 can be obtained. Next, an insulating layer is formed on the entire surface. The insulating layer is flattened to obtain the insulating layer segment 82'1 (insulating layer 82). Then, the composite oxide layer 23B and the photoelectric conversion layer 23A are formed on the insulating layer 82. In this way, the photoelectric conversion unit segments 10'1, 10'2, and 10'3 can be obtained.

[0461] Figure 39 A schematic layout diagram showing a first electrode and a charge storage electrode constituting a modification of the imaging element of Example 7 and transistors constituting a control unit, a reset transistor TR1 and a reset transistor TR2. rstThe other source / drain region 51B may be grounded instead of being connected to the power supply V DD .

[0462] [Example 8]

[0463] The imaging element of Example 8 and the like relate to the imaging elements of the second and sixth structures of the present invention. Figure 40 A schematic partial cross-sectional view showing an enlarged portion in which a charge accumulation electrode, a complex oxide layer, a photoelectric conversion layer, and a second electrode are stacked is shown. In the imaging element of Example 8, etc., the thickness of the photoelectric conversion layer segment is from the first photoelectric conversion unit segment 10'1 to the Nth photoelectric conversion unit segment 10' N Alternatively, in the imaging element of Example 8, etc., the width of the cross section of the stacked portion is constant, and the thickness of the cross section of the stacked portion, specifically, the thickness of the photoelectric conversion layer segment, gradually increases depending on the distance from the first electrode 21. More specifically, the thickness of the photoelectric conversion layer segment gradually increases. Note that the thickness of the photoelectric conversion layer segment increases in a step-like manner. The nth photoelectric conversion unit segment 10' n Photoelectric conversion layer section 23' in n The thickness is constant. When the nth photoelectric conversion unit segment 10' n Photoelectric conversion layer section 23' in n When the thickness is "1", the (n+1)th photoelectric conversion unit segment 10' (n+1) Photoelectric conversion layer section 23' in (n+1) Examples of the thickness include 2 to 10, but are not limited to these values. In Example 8, the thickness of the photoelectric conversion layer segments 23'1, 23'2, and 23'3 is gradually increased by gradually reducing the thickness of the charge accumulation electrode segments 24'1, 24'2, and 24'3. The thickness of the insulating layer segments 82'1, 82'2, and 82'3 is constant. In addition, in the photoelectric conversion layer segment, for example, it is only necessary to change the thickness of the photoelectric conversion layer segment by changing the thickness of a portion of the photoelectric conversion layer and keeping the thickness of a portion of the composite oxide layer unchanged.

[0464] In the imaging element of Example 8 and the like, the thickness of the photoelectric conversion layer section is gradually increased. Therefore, when |V 12 |≥|V 11 | state, to the n-th photoelectric conversion unit segment 10 ' n Towards the (n+1)th photoelectric conversion unit section 10' (n+1) A stronger electric field is applied, and the charge can be reliably prevented from flowing from the first photoelectric conversion unit section 10'1 to the first electrode 21. Then, when V 22 <V21 When the state is set, it is possible to reliably ensure that the charge flows from the first photoelectric conversion unit segment 10'1 to the first electrode 21 and ensure that the charge flows from the (n+1)th photoelectric conversion unit segment 10' (n+1) Flows to the nth photoelectric conversion unit section 10' n .

[0465] In this manner, in the imaging element of Example 8 and the like, the thickness of the photoelectric conversion layer section gradually changes from the first photoelectric conversion unit section to the Nth photoelectric conversion unit section. Alternatively, when the stacked portion comprising the charge accumulation electrode, insulating layer, composite oxide layer, and photoelectric conversion layer is cut along a YZ imaginary plane, the cross-sectional area of ​​the stacked portion varies depending on the distance from the first electrode. This creates a charge transfer gradient, making it possible to more easily and reliably transfer the charge generated by photoelectric conversion.

[0466] In the imaging element and the like of Example 8, when forming the first electrode 21, the charge accumulation electrode 24, the insulating layer 82, the composite oxide layer 23B, and the photoelectric conversion layer 23A, a conductive material layer for forming the charge accumulation electrode 24'3 is first formed on the interlayer insulating layer 81. The conductive material layer is patterned, and this conductive material layer is left in the regions where the photoelectric conversion unit segments 10'1, 10'2, and 10'3 and the first electrode 21 will be formed. This results in a portion of the first electrode 21 and the charge accumulation electrode 24'3. Subsequently, a conductive material layer for forming the charge accumulation electrode 24'2 is formed over the entire surface. The conductive material layer is patterned, and this conductive material layer is left in the regions where the photoelectric conversion unit segments 10'1 and 10'2 and the first electrode 21 will be formed. This results in a portion of the first electrode 21 and the charge accumulation electrode 24'2. Subsequently, a conductive material layer for forming the charge accumulation electrode 24'1 is formed over the entire surface. The conductive material layer is patterned and left in the region where the photoelectric conversion unit segment 10'1 and the first electrode 21 will be formed. This results in the first electrode 21 and the charge accumulation electrode 24'1. Next, an insulating layer 82 is conformally formed over the entire surface. Then, a composite oxide layer 23B and the photoelectric conversion layer 23A are formed on the insulating layer 82, and the photoelectric conversion layer 23A is planarized. In this manner, the photoelectric conversion unit segments 10'1, 10'2, and 10'3 are formed.

[0467] [Example 9]

[0468] Example 9 relates to an imaging element having the third structure. Figure 41A schematic partial cross-sectional view of an imaging element of Example 9 is shown. In the imaging element of Example 9, the materials used to constitute the insulating layer segments are different for adjacent photoelectric conversion unit segments. Here, the relative dielectric constant of the material used to constitute the insulating layer segments varies from the first photoelectric conversion unit segment 10'1 to the Nth photoelectric conversion unit segment 10'1. N Gradually decreases. In the imaging element of Example 9, etc., the same potential may be applied to all N charge accumulation electrode segments, or a different potential may be applied to each of the N charge accumulation electrode segments. In the latter case, as described in Example 10, the charge accumulation electrode segments 24'1, 24'2, and 24'3 provided separately from each other only need to be connected to the vertical drive circuit 112 constituting the drive circuit through the pad portions 641, 642, and 643.

[0469] Furthermore, by adopting the above configuration, a charge transfer gradient is formed. In the charge accumulation period, when V 12 ≥V 11 , the nth photoelectric conversion unit section can accumulate more charge than the (n+1)th photoelectric conversion unit section. In addition, when V is reached in the charge transfer period 22 <V 21 In the state of , it is possible to reliably ensure the flow of charge from the first photoelectric conversion unit section to the first electrode and ensure the flow of charge from the (n+1)th photoelectric conversion unit section to the nth photoelectric conversion unit section.

[0470] [Example 10]

[0471] Example 10 relates to an image pickup element having a fourth structure. Figure 42 A schematic partial cross-sectional view of an imaging element or the like of Example 10 is shown. In the imaging element or the like of Example 10, the materials used to constitute the charge accumulation electrode segments are different for adjacent photoelectric conversion unit segments. Here, the work function value of the material used to constitute the insulating layer segment varies from the first photoelectric conversion unit segment 10'1 to the Nth photoelectric conversion unit segment 10'1. N Gradually increases. In the imaging element of Example 10, etc., the same potential can be applied to all N charge accumulation electrode segments, or different potentials can be applied to each of the N charge accumulation electrode segments. In the latter case, the charge accumulation electrode segments 24'1, 24'2, and 24'3 are connected to the vertical drive circuit 112 constituting the drive circuit via the pad portions 641, 642, and 643.

[0472] [Example 11]

[0473] The imaging element of Example 11 and the like relate to the imaging element of the fifth structure. Figure 43A、 43B , 44A, and 44B show schematic plan views of the charge accumulation electrode segment in Example 11. Figure 45 Schematic layout diagram showing a first electrode and a charge accumulation electrode constituting a photoelectric conversion unit including a charge accumulation electrode and a transistor constituting a control unit of an imaging element etc. of Example 11. Schematic partial cross-sectional diagram of an imaging element etc. of Example 11 and Figure 42 or Figure 47 The schematic partial cross-sectional view shown is similar. In the imaging element of Example 11, etc., the area of ​​the charge accumulation electrode segment is from the first photoelectric conversion unit segment 10'1 to the Nth photoelectric conversion unit segment 10' N Gradually decreases. In the imaging element of Example 11, etc., the same potential can be applied to all N charge accumulation electrode segments, or a different potential can be applied to each of the N charge accumulation electrode segments. Specifically, as described in Example 10, the charge accumulation electrode segments 24'1, 24'2, and 24'3 provided separately from each other only need to be connected to the vertical drive circuit 112 constituting the drive circuit through the pad portions 641, 642, and 643.

[0474] In Example 11, the charge accumulation electrode 24 includes multiple charge accumulation electrode segments 24'1, 24'2, and 24'3. The number of charge accumulation electrode segments need only be two or more, and in Example 11, this number is set to "3." Furthermore, in the imaging element and the like of Example 11, the potential of the first electrode 21 is higher than that of the second electrode 22. Therefore, for example, a positive potential is applied to the first electrode 21, and a negative potential is applied to the second electrode 22. Therefore, during the charge transfer period, the potential applied to the charge accumulation electrode segment 24'1 located closest to the first electrode 21 is higher than the potential applied to the charge accumulation electrode segment 24'3 located farthest from the first electrode 21. In this way, by providing a potential gradient to the charge accumulation electrode 24, electrons that have stopped in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 are more reliably read out to the first electrode 21 and, further, to the first floating diffusion layer FD1. In other words, the charge accumulated in the composite oxide layer 23B and the like is read out to the control unit.

[0475] Furthermore, during the charge transfer period, by satisfying the following conditions: the potential of the charge accumulation electrode segment 24'3 < the potential of the charge accumulation electrode segment 24'2 < the potential of the charge accumulation electrode segment 24'1, electrons stopped in the region of the composite oxide layer 23B and the like can be read out all at once to the first floating diffusion layer FD1. At the same time, during the charge transfer period, by gradually changing the potential of the charge accumulation electrode segment 24'3, the potential of the charge accumulation electrode segment 24'2, and the potential of the charge accumulation electrode segment 24'1 (i.e., by changing the potential of the charge accumulation electrode segment 24'3, the potential of the charge accumulation electrode segment 24'2, and the potential of the charge accumulation electrode segment 24'1 in a step-like or inclined manner), electrons stopped in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode segment 24'3 can be transferred to the region of the composite oxide layer 23B and the like facing the charge accumulation electrode segment 24'2. Subsequently, the electrons stopped in the region of the composite oxide layer 23B etc. facing the charge accumulation electrode segment 24'2 can be transferred to the region of the composite oxide layer 23B etc. facing the charge accumulation electrode segment 24'1. Subsequently, the electrons stopped in the region of the composite oxide layer 23B etc. facing the charge accumulation electrode segment 24'1 can be reliably read out to the first floating diffusion layer FD1.

[0476] Figure 46 A schematic layout diagram showing a first electrode and a charge accumulation electrode constituting a modification of the imaging element of Example 11 and transistors constituting a control unit, a reset transistor TR3 and a reset transistor TR4. rst The other source / drain region 51B may be grounded instead of being connected to the power supply V DD .

[0477] In the imaging element of Example 11, by adopting the above-mentioned structure, a charge transfer gradient is also formed. That is, the area of ​​the charge accumulation electrode segment ranges from the first photoelectric conversion unit segment 10'1 to the Nth photoelectric conversion unit segment 10'1. N Therefore, when V 12 ≥V 11 , the nth photoelectric conversion unit section can accumulate more charge than the (n+1)th photoelectric conversion unit section. In addition, when V is reached in the charge transfer period 22 <V 21 In the state of , it is possible to reliably ensure the flow of charge from the first photoelectric conversion unit section to the first electrode and ensure the flow of charge from the (n+1)th photoelectric conversion unit section to the nth photoelectric conversion unit section.

[0478] [Example 12]

[0479] Example 12 relates to an imaging element having the sixth structure. Figure 47 A schematic partial cross-sectional view of the imaging element, etc. of Example 12 is shown. Figure 48A and Figure 48B A schematic plan view of a charge accumulation electrode section in Example 12 is shown. The image pickup element or the like in Example 12 includes a photoelectric conversion unit formed by stacking a first electrode 21 , a complex oxide layer 23B, a photoelectric conversion layer 23A, and a second electrode 22 . The photoelectric conversion unit also includes a charge accumulation electrode 24 (24″1, 24″2, and 24″3), which is arranged separately from the first electrode 21 and faces the composite oxide layer 23B via the insulating layer 82. In addition, if the stacking direction of the charge accumulation electrodes 24 (24″1, 24″2, and 24″3), the insulating layer 82, the composite oxide layer 23B, and the photoelectric conversion layer 23A is defined as the Z direction, and the direction away from the first electrode 21 is defined as the X direction, then when the stacked portion where the charge accumulation electrodes 24 (24″1, 24″2, and 24″3), the insulating layer 82, the composite oxide layer 23B, and the photoelectric conversion layer 23A are stacked is cut with a YZ imaginary plane, the cross-sectional area of ​​the stacked portion varies depending on the distance from the first electrode 21.

[0480] Specifically, in the imaging element of Example 12, etc., the thickness of the cross section of the stacked portion is constant, and the width of the cross section of the stacked portion becomes narrower as the stacked portion moves away from the first electrode 21. Note that the above width may be continuously narrowed (see Figure 48A ), or it may be narrowed in steps (see Figure 48B ).

[0481] In this manner, in the imaging element of Example 12, etc., when the stacked portion in which the charge accumulation electrodes 24 (24″1, 24″2, and 24″3), the insulating layer 82, and the photoelectric conversion layer 23A are stacked is cut by the YZ imaginary plane, the cross-sectional area of ​​the stacked portion changes depending on the distance from the first electrode. Thus, a charge transfer gradient is formed, and the charge generated by the photoelectric conversion can be transferred more easily and reliably.

[0482] [Example 13]

[0483] Example 13 relates to the solid-state imaging device of the first configuration and the second configuration.

[0484] A solid-state imaging device according to Embodiment 13 includes:

[0485] The photoelectric conversion unit is formed by stacking the first electrode 21 , the complex oxide layer 23B, the photoelectric conversion layer 23A, and the second electrode 22 .

[0486] The solid-state imaging device of Example 13 includes a plurality of imaging elements, in each of which the photoelectric conversion unit further includes a charge accumulation electrode 24 arranged separately from the first electrode 21 and facing the complex oxide layer 23B via the insulating layer 82 .

[0487] A plurality of imaging elements constitute an imaging element block.

[0488] The first electrode 21 is shared by a plurality of imaging elements constituting the imaging element block.

[0489] Alternatively, the solid-state imaging device of Embodiment 13 includes a plurality of imaging elements and the like as described in Embodiments 1 to 12.

[0490] In Example 13, a single floating diffusion layer is provided for multiple imaging elements. Furthermore, by appropriately controlling the timing of the charge transfer period, multiple imaging elements can share a single floating diffusion layer. Furthermore, in this case, multiple imaging elements can share a single contact hole.

[0491] Note that the solid-state imaging device of Example 13 has basically the same configuration and structure as those described in Examples 1 to 12, except that a plurality of imaging elements constituting the imaging element block share the first electrode 21 .

[0492] Figure 49 (Example 13) Figure 50 (First variation of Example 13), Figure 51 (Second variation of Example 13), Figure 52 (Third variation of Example 13) and Figure 53 (Fourth Modification of Embodiment 13) The arrangement state of the first electrode 21 and the charge accumulation electrode 24 in the solid-state imaging device of Embodiment 13 is schematically shown. Figure 49 、 50 , 53 and 54 show 16 imaging elements, etc., and Figure 51 and 52 12 imaging elements, etc. are shown separately. In addition, two imaging elements, etc. constitute an imaging element block. The imaging element block is surrounded by a dotted line. Subscripts attached to the first electrode 21 and the charge accumulation electrode 24 are shown to distinguish the first electrode 21 and the charge accumulation electrode 24, respectively. This applies similarly to the following description. In addition, an on-chip microlens ( Figures 49 to 58 (not shown) is arranged above one imaging element, etc. In addition, in one imaging element block, two charge accumulation electrodes 24 are arranged so that the first electrode 21 is inserted between the two charge accumulation electrodes 24 (see Figure 49 and Figure 50 Alternatively, one first electrode 21 is arranged to face two charge accumulation electrodes 24 arranged side by side (see Figure 53 and Figure 54 ). That is, the first electrode is arranged adjacent to the charge accumulation electrode of each imaging element, etc. Alternatively, the first electrode is arranged adjacent to the charge accumulation electrodes of a part of the plurality of imaging elements, etc., and is not arranged adjacent to the remaining charge accumulation electrodes of the plurality of imaging elements, etc. (see Figure 51 and Figure 52 ). In this case, the transfer of charge from the remaining imaging elements of the plurality of imaging elements, etc. to the first electrode is carried out via a part of the imaging elements, etc. Preferably, the distance A between the charge accumulation electrodes constituting the imaging element, etc. and the charge accumulation electrodes constituting the imaging element, etc. is longer than the distance B between the first electrode and the charge accumulation electrodes in the imaging element, etc. adjacent to the first electrode, so as to ensure that the charge is transferred from each imaging element, etc. to the first electrode. In addition, preferably, the farther the position of the imaging element, etc. is from the first electrode, the larger the value of the distance A. In addition, in Figure 50 、 Figure 52 and Figure 54 In the example shown, the charge transfer control electrode 27 is provided between a plurality of imaging elements constituting the imaging element block. By providing the charge transfer control electrode 27, the transfer of charge in the imaging element blocks located on both sides of the charge transfer control electrode 27 can be reliably suppressed. Note that when the potential applied to the charge transfer control electrode 27 is referred to as V 17 When V 12 >V 17 .

[0493] The charge transfer control electrode 27 can be formed on the first electrode side at the same level as the first electrode 21 or the charge accumulation electrode 24, or at a different level (specifically, a lower level than the first electrode 21 or the charge accumulation electrode 24). In the former case, since the distance between the charge transfer control electrode 27 and the photoelectric conversion layer can be shortened, the potential can be easily controlled. At the same time, since the distance between the charge transfer control electrode 27 and the charge accumulation electrode 24 can be shortened, the latter case is conducive to miniaturization.

[0494] Hereinafter, the first electrode 212 and the two charge accumulation electrodes 24 will be described. 21 and 24 22 Operation of the imaging element block.

[0495] During the charge accumulation period, the drive circuit sets the potential V a is applied to the first electrode 212, and the potential V A applied to the charge accumulation electrode 24 21 and 24 22The light incident on the photoelectric conversion layer 23A causes photoelectric conversion in the photoelectric conversion layer 23A. The holes generated by the photoelectric conversion are transferred from the second electrode 22 through the wiring V OU At the same time, the potential of the first electrode 212 is set higher than the potential of the second electrode 22, that is, for example, a positive potential is applied to the first electrode 212, and a negative potential is applied to the second electrode 22. Therefore, V A ≥V a , preferably, satisfying V A >V a As a result, electrons generated by photoelectric conversion are attracted to the charge accumulation electrode 24. 21 and 24 22 , and the electrons stop at the composite oxide layer 23B and the like facing the charge accumulation electrode 24 21 and 24 22 That is, the charge is accumulated in the composite oxide layer 23B and the like. Since V A ≥V a Therefore, the electrons generated in the photoelectric conversion layer 23A are not transferred toward the first electrode 212. As the time of photoelectric conversion passes, the composite oxide layer 23B and the like facing the charge storage electrode 24 21 and 24 22 The potential in the region becomes more negative.

[0496] At the end of the charge accumulation period, a reset operation is performed. As a result, the potential of the first floating diffusion layer is reset, and the potential of the first floating diffusion layer becomes the potential V of the power supply. DD .

[0497] After the reset operation is completed, the charge is read out. That is, during the charge transfer period, the drive circuit sets the potential V b Applied to the first electrode 212, the potential V 21-B applied to the charge accumulation electrode 24 21 and set the potential V 22-B applied to the charge accumulation electrode 24 22 Here, V 21-B <V b <V 22-B As a result, the charge storage electrode 24 is stopped at the composite oxide layer 23B and the like. 21 The electrons in the region of are read out to the first electrode 212 and further read out to the first floating diffusion layer. That is, the electrons accumulated in the composite oxide layer 23B and the like facing the charge storage electrode 24 21 The charge in the region is read out to the control unit. When the reading is completed, V 22-B ≤V 21-B <V b . Note that in Figure 53 and Figure 54 In the example shown, V 22-B <V b <V 21-B As a result, the charge storage electrode 24 is stopped at the composite oxide layer 23B and the like. 22 The electrons in the region are read out to the first electrode 212 and further read out to the first floating diffusion layer. Figure 51 and Figure 52 In the example shown, the charge storage electrode 24 is stopped at the composite oxide layer 23B and the like. 22 The electrons in the region can pass through the charge accumulation electrode 24 22 The adjacent first electrode 213 is read out to the first floating diffusion layer. In this way, the charge accumulated in the composite oxide layer 23B and the like facing the charge accumulation electrode 24 22 The charge in the region is read out to the control unit. Note that when the charge accumulated in the composite oxide layer 23B and the like faces the charge accumulation electrode 24 21 When reading of the charges in the region is completed, the potential of the first floating diffusion layer can be reset.

[0498] Figure 59A An example of readout driving in the image pickup element block of Example 13 is shown.

[0499] The charge accumulation electrode 24 is read out by the following steps A to H. 21 and the charge accumulation electrode 24 22 Signals of two corresponding imaging elements, etc.

[0500] [Step-A]

[0501] Input the auto-zero signal to the comparator

[0502] [Step-B]

[0503] Reset operation of a shared floating diffusion layer

[0504] [Step-C]

[0505] In the case of the charge accumulation electrode 24 21 P-phase reading in the corresponding imaging element and charge transfer to the first electrode 212

[0506] [Step-D]

[0507] In the case of the charge accumulation electrode 24 21 D-phase reading in the corresponding imaging element and charge transfer to the first electrode 212

[0508] [Step-E]

[0509] Reset operation of a shared floating diffusion layer

[0510] [Step-F]

[0511] Input the auto-zero signal to the comparator

[0512] [Step-G]

[0513] In the case of the charge accumulation electrode 24 22 P-phase reading in the corresponding imaging element and charge transfer to the first electrode 212

[0514] [Step-H]

[0515] In the case of the charge accumulation electrode 24 22 D-phase reading in the corresponding imaging element and charge transfer to the first electrode 212

[0516] Based on the correlated double sampling (CDS) process, the difference between the P phase reading in [step-C] and the D phase reading in [step-D] is the difference between the charge accumulation electrode 24 and the charge accumulation electrode 24. 21 The difference between the P phase reading in [Step-G] and the D phase reading in [Step-H] is the difference between the P phase reading and the D phase reading in [Step-H], and the difference between the P phase reading and the D phase reading in [Step-G] is the difference between the P phase reading and the D phase reading in [Step-H], and the difference between the P phase reading and the D phase reading in [Step-H] is the difference between the P phase reading and the D phase reading in [Step-G], and the difference between the 22 Signals from corresponding imaging elements, etc.

[0517] Note that the operation of [Step-E] can be omitted (see Figure 59B ). In addition, the operation of [Step-F] can be omitted. In this case, the operation of [Step-G] can be further omitted (see Figure 59C The difference between the P phase reading in [Step-C] and the D phase reading in [Step-D] is due to the difference between the charge accumulation electrode 24 and the charge accumulation electrode 24. 21 The difference between the D phase reading in [step-D] and the D phase reading in [step-H] is the difference between the D phase reading in step-D and the D phase reading in step-H. 22 Signals from corresponding imaging elements, etc.

[0518] In the diagram schematically showing the arrangement state of the first electrode 21 and the charge accumulation electrode 24 Figure 55 (Sixth variation of Example 13) and Figure 56 In the modification of the seventh modification of embodiment 13, the image pickup element block includes four image pickup elements, etc. The operation of these solid-state image pickup devices can be basically similar to that of Figures 49-54 The operation of the solid-state imaging device is shown.

[0519] In the diagram schematically showing the arrangement state of the first electrode 21 and the charge accumulation electrode 24 Figure 57 and Figure 58In the eighth and ninth modified examples of the present invention, the image pickup element block includes 16 image pickup elements. Figure 57 and 58 As shown, the charge transfer control electrodes 27A1, 27A2 and 27A3 are respectively provided on the charge accumulation electrode 24. 11 and the charge accumulation electrode 24 12 Between the charge accumulation electrode 24 12 and the charge accumulation electrode 24 13 Between, and the charge accumulation electrode 24 13 and the charge accumulation electrode 24 14 In addition, Figure 58 As shown, the charge transfer control electrodes 27B1, 27B2 and 27B3 are respectively provided on the charge accumulation electrode 24. 21 ,twenty four 31 and 24 41 and the charge accumulation electrode 24 22 ,twenty four 32 and 24 42 Between the charge accumulation electrode 24 22 ,twenty four 32 and 24 42 and the charge accumulation electrode 24 23 ,twenty four 33 and 24 43 Between, and the charge accumulation electrode 24 23 ,twenty four 33 and 24 43 and the charge accumulation electrode 24 24 ,twenty four 34 and 24 44 In addition, the charge transfer control electrode 27C is provided between the imaging element block and the imaging element block. In addition, in these solid-state imaging devices, by controlling the 16 charge accumulation electrodes 24, the charge accumulated in the composite oxide layer 23B can be read from the first electrode 21.

[0520] [STEP-10]

[0521] Specifically, first, the charge storage electrode 24 is read out from the first electrode 21 at the composite oxide layer 23B and the like. 11 Next, the charge is accumulated in the region of the first electrode 21 through the complex oxide layer 23B and the like toward the charge accumulation electrode 24. 11 The area of ​​the composite oxide layer 23B facing the charge accumulation electrode 24 is read out. 12 Next, the charge is accumulated in the region of the first electrode 21 through the complex oxide layer 23B and the like toward the charge accumulation electrode 24. 12 and the charge accumulation electrode 24 11The area of ​​the composite oxide layer 23B facing the charge accumulation electrode 24 is read out. 13 The charge accumulated in the region.

[0522] [STEP-20]

[0523] Then, on the surface of the composite oxide layer 23B and the like facing the charge storage electrode 24 21 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 11 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 22 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 12 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 23 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 13 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 24 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 14 area.

[0524] [STEP-21]

[0525] The composite oxide layer 23B and the like face the charge storage electrode 24. 31 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 21 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 32 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 22 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 33 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 23 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 34 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 24 area.

[0526] [STEP-22]

[0527] The composite oxide layer 23B and the like face the charge storage electrode 24. 41 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 31In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 42 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 32 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 43 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 33 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 44 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 34 area.

[0528] [STEP-30]

[0529] Then, by executing [Step-10] again, the charge storage electrode 24 in the composite oxide layer 23B and the like can be read via the first electrode 21. 21 The charge accumulated in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 22 The charge accumulated in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 23 The charge accumulated in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 24 The charge accumulated in the region.

[0530] [STEP-40]

[0531] Then, on the surface of the composite oxide layer 23B and the like facing the charge storage electrode 24 21 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 11 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 22 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 12 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 23 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 13 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 24 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 14 area.

[0532] [STEP-41]

[0533] The composite oxide layer 23B and the like face the charge storage electrode 24. 31 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 21 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 32 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 22 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 33 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 23 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 34 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 24 area.

[0534] [STEP-50]

[0535] Then, by executing [Step-10] again, the charge storage electrode 24 in the composite oxide layer 23B and the like can be read via the first electrode 21. 31 The charge accumulated in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 32 The charge accumulated in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 33 The charge accumulated in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 34 The charge accumulated in the region.

[0536] [STEP-60]

[0537] Then, on the surface of the composite oxide layer 23B and the like facing the charge storage electrode 24 21 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 11 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 22 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 12 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 23 The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 13 In the region where the composite oxide layer 23B and the like face the charge storage electrode 24 24The charge accumulated in the region is transferred to the composite oxide layer 23B and the like facing the charge accumulation electrode 24. 14 area.

[0538] [STEP-70]

[0539] Then, by executing [Step-10] again, the charge storage electrode 24 in the composite oxide layer 23B and the like can be read via the first electrode 21. 41 The charge accumulated in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 42 The charge accumulated in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 43 The charge accumulated in the region of the composite oxide layer 23B and the like facing the charge accumulation electrode 24 44 The charge accumulated in the region.

[0540] In the solid-state imaging device of Example 13, since the first electrode is shared by the plurality of imaging elements, etc., constituting the imaging element block, the configuration and structure of the pixel region in which the plurality of imaging elements, etc. are arranged can be simplified and miniaturized. Note that the plurality of imaging elements, etc. provided for a single floating diffusion layer may be composed of a plurality of first-type imaging elements, or may be composed of at least one first-type imaging element and one or more second-type imaging elements.

[0541] [Example 14]

[0542] Example 14 is a modification of Example 13. In the diagram schematically showing the arrangement of the first electrode 21 and the charge accumulation electrode 24, Figure 60 、 61 In the solid-state imaging device of Example 14 shown in 62 and 63, the imaging element block includes two imaging elements. In addition, an on-chip microlens 14 is provided above the imaging element block. Figure 61 and 63 In the illustrated example, the charge transfer control electrode 27 is provided between a plurality of image pickup elements and the like constituting the image pickup element block.

[0543] For example, the charge storage electrode 24 constituting the image pickup element block 11 ,twenty four 21 ,twenty four 31 and 24 41 The corresponding photoelectric conversion layer is highly sensitive to light incident from the upper right of the figure. 12 ,twenty four 22 ,twenty four 32 and 24 42The corresponding photoelectric conversion layer is highly sensitive to light incident from the upper left in the figure. Therefore, for example, by 11 The imaging element and the charge accumulation electrode 24 12 In addition, if the image plane phase difference signal is obtained by combining the image pickup element 24 with the charge accumulation electrode 24, the image plane phase difference signal can be obtained. 11 The signal from the image pickup element or the like is added to the signal from the charge accumulation electrode 24. 12 If the signal of the imaging element etc. is received, then one imaging element etc. can be composed of a combination of these imaging elements etc. Figure 60 In the example shown, the first electrode 211 is provided on the charge accumulation electrode 24. 11 and the charge accumulation electrode 24 12 However, if Figure 62 As in the example shown, by arranging one first electrode 211 to face two charge accumulation electrodes 24 arranged side by side, 11 and 24 12 , which can further improve the sensitivity.

[0544] So far, the present invention has been described based on the preferred embodiments. However, the present invention is not limited to the above-mentioned embodiments. The structures and constructions, manufacturing conditions, manufacturing methods and materials used of the imaging elements, stacked imaging elements, and solid-state imaging devices described in the embodiments are illustrative and can be appropriately changed. The imaging elements and the like of the embodiments can be appropriately combined. For example, the imaging element of Example 7, etc., the imaging element of Example 8, etc., the imaging element of Example 9, etc., the imaging element of Example 10, etc., and the imaging element of Example 11, etc. can be arbitrarily combined. The imaging element of Example 7, etc., the imaging element of Example 8, etc., the imaging element of Example 9, etc., the imaging element of Example 10, etc., and the imaging element of Example 12, etc. can be arbitrarily combined.

[0545] In some cases, the floating diffusion layers FD1 , FD2 , FD3 , 51C, 45C, and 46C can also be shared.

[0546] In an embodiment, the composite oxide layer contains only IGZO. However, alternatively, the composite oxide layer (inorganic oxide semiconductor material layer) can contain at least two elements selected from the group consisting of indium, tungsten, tin, and zinc. Specifically, the first semiconductor material layer can contain indium-tungsten oxide (IWO), indium-tungsten-zinc oxide (IWZO), indium-tin-zinc oxide (ITZO), or zinc-tin oxide (ZTO). More specifically, the composite oxide layer can contain In-W oxide, In-Sn oxide, In-Zn oxide, W-Sn oxide, W-Zn oxide, Sn-Zn oxide, In-W-Sn oxide, In-W-Zn oxide, In-Sn-Zn oxide, or In-W-Sn-Zn oxide. Note that in these configurations, by performing composition modulation during formation (i.e., by changing the composition in a gradient or stepwise manner), it is only necessary to form the composite oxide layer (or the first and second layers constituting the composite oxide layer). Furthermore, similar to the case where the composite oxide layer includes IGZO, these structures also allow carriers (e.g., photoelectrons) generated by photoelectric conversion to flow from the photoelectric conversion layer into the composite oxide layer, resulting in minimal carrier stagnation at the interface between the photoelectric conversion layer and the composite oxide layer. Furthermore, the carrier transport capability of the photoelectric conversion layer and the composite oxide layer as a whole can be improved. As a result, it is possible to provide an imaging element or the like that has excellent transport characteristics for charges accumulated in the photoelectric conversion layer without adversely affecting the photoresponsivity of the imaging element.

[0547] Furthermore, an intermediate layer can be formed between the first layer 23B1 and the second layer 23B2 .

[0548] For example, Figure 64 A modified example of the imaging element and the like described in Example 1 is shown, in which the first electrode 21 can extend through the opening 85A formed in the insulating layer 82 and be connected to the composite oxide layer 23B.

[0549] Alternatively, for example, Figure 65 A modification of the imaging element and the like described in Example 1 is shown. Figure 66A An enlarged schematic partial cross-sectional view of the first electrode portion, etc., is shown, in which the edge of the top surface of the first electrode 21 is covered by the insulating layer 82, and the first electrode 21 is exposed on the bottom surface of the opening 85B; and when the surface of the insulating layer 82 in contact with the top surface of the first electrode 21 is referred to as the first surface 82a, and the surface of the insulating layer 82 in contact with the portion of the composite oxide layer 23B facing the charge accumulation electrode 24 is referred to as the second surface 82b, the side surface of the opening 85B has a slope that widens from the first surface 82a toward the second surface 82b. In this way, by tilting the side surface of the opening 85B, the movement of charge from the composite oxide layer 23B to the first electrode 21 becomes smoother. Note that in Figure 66A In the example shown, the side surfaces of the opening 85B are rotationally symmetrical with respect to the axis of the opening 85B. Figure 66B As shown, the opening 85C can be formed such that the side surface of the opening 85C having an inclined surface that widens from the first surface 82a toward the second surface 82b is positioned on the charge accumulation electrode 24 side. As a result, it is difficult for charges to move from the portion of the composite oxide layer 23B opposite to the charge accumulation electrode 24 through the opening 85C. In addition, the side surface of the opening 85B has an inclination that widens from the first surface 82a toward the second surface 82b. However, as Figure 66A As shown, the edge of the side surface of the opening 85B in the second surface 82b may be located outside the edge of the first electrode 21; or, as shown in FIG. Figure 66C As shown, it can be located inside the edge of the first electrode 21. By adopting the former configuration, the transfer of charges is further promoted. By adopting the latter configuration, the change in shape when forming the opening can be reduced.

[0550] These openings 85B and 85C can be formed by reflowing an etching mask including a resist material to be formed when forming openings in the insulating layer based on an etching method, and etching the insulating layer 82 using the etching mask.

[0551] Alternatively, regarding the charge discharge electrode 26 described in Example 5, as Figure 67 As shown, the following form can be adopted: wherein the composite oxide layer 23B extends in the second opening 86A formed in the insulating layer 82 and is connected to the charge discharge electrode 26, the edge of the top surface of the charge discharge electrode 26 is covered by the insulating layer 82, and the charge discharge electrode 26 is exposed on the bottom surface of the second opening 86A, and when the surface of the insulating layer 82 in contact with the top surface of the charge discharge electrode 26 is referred to as the third surface 82c, and the surface of the insulating layer 82 in contact with the portion of the composite oxide layer 23B facing the charge accumulation electrode 24 is referred to as the second surface 82b, the side surface of the second opening 86A has a slope that widens from the third surface 82c toward the second surface 82b.

[0552] In addition, for example, Figure 68 A modified example of the imaging element and the stacked imaging element described in Example 1 is shown, in which a configuration can be adopted in which light is incident from the second electrode 22 side and the light-shielding layer 15 is formed on the light-incident side of the second electrode 22. Note that various wirings provided on the light-incident side of the photoelectric conversion layer can also function as the light-shielding layer.

[0553] Note that in Figure 68 In the example shown, the light shielding layer 15 is formed above the second electrode 22, that is, the light shielding layer 15 is formed on the light incident side of the second electrode 22 and above the first electrode 21. However, as Figure 69 As shown, the light shielding layer 15 may also be provided on the light incident side surface of the second electrode 22. Figure 70 As shown, in some cases, the light shielding layer 15 may be formed in the second electrode 22 .

[0554] Alternatively, a structure can be adopted in which light is incident from the second electrode 22 side and light is not incident on the first electrode 21. Specifically, as Figure 68 As shown, the light shielding layer 15 is formed on the light incident side of the second electrode 22 and above the first electrode 21. Alternatively, as Figure 72 As shown, it is possible to adopt a structure in which the on-chip microlens 14 is provided above the charge accumulation electrode 24 and the second electrode 22, and light incident on the on-chip microlens 14 is collected by the charge accumulation electrode 24 and does not reach the first electrode 21. Note that, as described in Example 4, in the case where the transfer control electrode 25 is provided, it is possible to adopt a structure in which light is not incident on the first electrode 21 and the transfer control electrode 25. Specifically, as Figure 71 As shown, the light shielding layer 15 can be formed above the first electrode 21 and the transmission control electrode 25. Alternatively, a structure can be adopted in which light incident on the on-chip microlens 14 does not reach the first electrode 21 or the first electrode 21 and the transmission control electrode 25.

[0555] By adopting the above-described configurations and structures, or alternatively, by providing a light-shielding layer 15, light is incident only on the portion of the photoelectric conversion layer 23A located above the charge accumulation electrode 24, or alternatively, by designing the on-chip microlens 14, the portion of the photoelectric conversion layer 23A located above the first electrode 21 (or above the first electrode 21 and the transfer control electrode 25) does not contribute to photoelectric conversion. Consequently, all pixels can be reset simultaneously more reliably, and a global shutter function can be more easily implemented. Specifically, a method for driving a solid-state imaging device including a plurality of imaging elements having the above-described configurations and structures repeats the following steps:

[0556] In all imaging elements, the charge is accumulated in the composite oxide layer 23B, etc., and all the charge in the first electrode 21 is released to the outside of the system at the same time; then

[0557] In all imaging elements and the like, the charges accumulated in the composite oxide layer 23B and the like are all transferred to the first electrode 21 at the same time, and after the transfer is completed, the charges transferred to the first electrode 21 are sequentially read in each imaging element and the like.

[0558] In the above-described driving method for a solid-state imaging device, each imaging element, etc., has a structure in which light incident from the second electrode side does not impinge on the first electrode. Furthermore, in all imaging elements, etc., while charge is accumulated in the composite oxide layer, etc., the charge in the first electrode is simultaneously released to the outside of the system. Therefore, the first electrode can be reliably reset simultaneously in all imaging elements, etc. Furthermore, subsequently, in all imaging elements, etc., the charge accumulated in the composite oxide layer, etc. is simultaneously transferred to the first electrode. After the transfer is complete, the charge transferred to the first electrode is sequentially read out in each imaging element, etc. Therefore, a so-called global shutter function can be easily implemented.

[0559] In addition, in a modification of Example 4, Figure 73 As shown, a plurality of transfer control electrodes may be provided from the position closest to the first electrode 21 toward the charge accumulation electrode 24. Note that Figure 73 An example in which two transfer control electrodes 25A and 25B are provided is shown. Alternatively, a structure can be adopted in which the on-chip microlens 14 is provided above the charge accumulation electrode 24 and the second electrode 22, and light incident on the on-chip microlens 14 is collected by the charge accumulation electrode 24 and does not reach the first electrode 21 and the transfer control electrodes 25A and 25B.

[0560] exist Figure 37 and 38 In the embodiment 7 shown, the thickness of the charge accumulation electrode segments 24'1, 24'2 and 24'3 is gradually reduced to gradually increase the thickness of the insulating layer segments 82'1, 82'2 and 82'3. Figure 74 This schematic partial cross-sectional view is obtained by enlarging a portion of a modified example of Example 7 where a charge accumulation electrode, a complex oxide layer, a photoelectric conversion layer, and a second electrode are stacked. The thickness of the charge accumulation electrode segments 24'1, 24'2, and 24'3 can be constant, while the thickness of the insulating layer segments 82'1, 82'2, and 82'3 can gradually increase. Note that the thickness of the photoelectric conversion layer segments 23'1, 23'2, and 23'3 is constant.

[0561] In addition, Figure 40 In the embodiment 8 shown, the thickness of the charge accumulation electrode sections 24'1, 24'2 and 24'3 is gradually reduced, thereby gradually increasing the thickness of the photoelectric conversion layer sections 23'1, 23'2 and 23'3. Figure 75A schematic partial cross-sectional view obtained by enlarging a portion of a modified example of Example 8 in which a charge accumulation electrode, a photoelectric conversion layer and a second electrode are stacked is shown. By making the thickness of the charge accumulation electrode segments 24'1, 24'2 and 24'3 constant and gradually reducing the thickness of the insulating layer segments 82'1, 82'2 and 82'3, the thickness of the photoelectric conversion layer segments 23'1, 23'2 and 23'3 can be gradually increased.

[0562] It goes without saying that the above-mentioned various modifications can also be applied to Embodiments 2 to 14.

[0563] In the embodiments, electrons are used as signal charges, and the conductivity type of the photoelectric conversion layer formed on the semiconductor substrate is n-type. However, the present invention can also be applied to solid-state imaging devices that use holes as signal charges. In this case, each semiconductor region only needs to be composed of semiconductor regions of opposite conductivity types, and the conductivity type of the photoelectric conversion layer formed on the semiconductor substrate only needs to be p-type.

[0564] In the embodiment, the case where the present invention is applied to a CMOS-type solid-state imaging device has been described as an example, in which the unit pixels that detect the signal charge corresponding to the amount of incident light as a physical quantity are arranged in a matrix. However, the present invention is not limited to the application of CMOS-type solid-state imaging devices, and the present invention can also be applied to CCD-type solid-state imaging devices. In the latter case, the vertical transfer register having a CCD-type structure transfers the signal charge in the vertical direction, the horizontal transfer register transfers the signal charge in the horizontal direction, and the signal charge is amplified to output a pixel signal (image signal). In addition, the present invention is not limited to an ordinary column-type solid-state imaging device, in which pixels are formed in a two-dimensional matrix and a column signal processing circuit is provided for each pixel column. In addition, in some cases, the selection transistor can be omitted.

[0565] Furthermore, the imaging element and stacked imaging element of the present invention are not limited to applications in solid-state imaging devices that detect the distribution of incident visible light and depict this distribution as an image. Rather, the imaging element and stacked imaging element of the present invention can also be applied to solid-state imaging devices that depict the distribution of incident infrared light, X-rays, particles, and the like as an image. Furthermore, in a broader sense, the present invention can be applied to general-purpose solid-state imaging devices (physical quantity distribution detection devices) that detect the distribution of other physical quantities (e.g., pressure and capacitance) and image this physical quantity as an image, such as fingerprint detection sensors.

[0566] Furthermore, the present invention is not limited to solid-state imaging devices that sequentially scan the unit pixels of an imaging area in rows and read pixel signals from each unit pixel. The present invention can also be applied to XY address-type solid-state imaging devices that select arbitrary pixels on a pixel-by-pixel basis and read pixel signals from the selected pixels on a pixel-by-pixel basis. The solid-state imaging device may be formed as a single chip, or may be in the form of a module having an imaging function, in which the imaging area and a drive circuit or optical system are packaged together.

[0567] Furthermore, the present invention is not limited to application to solid-state imaging devices, but can also be applied to imaging devices. Here, an imaging device refers to a camera system (e.g., a digital camera or a digital video camera) or an electronic device with an imaging function (e.g., a mobile phone). A module form (i.e., a camera module) mounted on an electronic device is sometimes used as an imaging device.

[0568] Figure 77 As a conceptual diagram, an example is shown in which a solid-state imaging device 201 including an imaging element and a stacked imaging element of the present invention is used in an electronic device (camera) 200. The electronic device 200 includes the solid-state imaging device 201, an optical lens 210, a shutter device 211, a drive circuit 212, and a signal processing circuit 213. The optical lens 210 forms an image of image light (incident light) from a subject on the imaging surface of the solid-state imaging device 201. As a result, signal charge is stored in the solid-state imaging device 201 for a period of time. The shutter device 211 controls the illumination period and light shielding period of the solid-state imaging device 201. The drive circuit 212 provides a drive signal for controlling the transmission operation of the solid-state imaging device 201 and the shutter operation of the shutter device 211. The solid-state imaging device 201 transmits a signal using the drive signal (timing signal) provided by the drive circuit 212. The signal processing circuit 213 performs various signal processing. The video signal that has undergone signal processing is stored in a storage medium such as a memory or output to a monitor. In such an electronic device 200, the pixel size of the solid-state imaging device 201 can be reduced and the transmission efficiency can be improved, thereby achieving an electronic device 200 with improved pixel characteristics. The electronic device 200 to which the solid-state imaging device 201 can be applied is not limited to cameras, and the solid-state imaging device 201 can be applied to imaging devices such as digital cameras or camera modules for mobile devices (e.g., mobile phones).

[0569] Note that the present invention can have the following configurations.

[0570] [A01] <<Image Sensor: First Aspect>>

[0571] An imaging element includes a photoelectric conversion unit formed by stacking a first electrode, a photoelectric conversion layer, and a second electrode, wherein

[0572] A composite oxide layer including indium composite oxide is formed between the first electrode and the photoelectric conversion layer.

[0573] The composite oxide layer includes a first layer adjacent to the first electrode and a second layer adjacent to the photoelectric conversion layer, and

[0574] The first layer has a higher indium composition (indium atomic content) than the second layer.

[0575] [A02] <<Image Sensor: Second Aspect>>

[0576] An imaging element includes a photoelectric conversion unit formed by stacking a first electrode, a photoelectric conversion layer, and a second electrode, wherein

[0577] A composite oxide layer including an indium-gallium-zinc composite oxide is formed between the first electrode and the photoelectric conversion layer.

[0578] The composite oxide layer includes a first layer adjacent to the first electrode and a second layer adjacent to the photoelectric conversion layer.

[0579] The first layer has a higher indium composition (indium atomic content) than the second layer, or

[0580] The first layer has a lower gallium composition (gallium atomic content) than the second layer, or

[0581] The first layer has a higher zinc composition (zinc atomic content) than the second layer.

[0582] [A03] The imaging element according to [A02], wherein

[0583] When the indium-gallium-zinc composite oxide is composed of (ZnO) X (Ga2O3) 1-X 、(Ga2O3) Y (In2O3) 1-Y , and (In2O3) Z (ZnO) 1-Z When indicating,

[0584] The value of X in the first layer is greater than the value of X in the second layer, or

[0585] The value of Y in the first layer is lower than the value of Y in the second layer, or

[0586] The value of Z in the first layer is higher than the value of Z in the second layer.

[0587] [A04]The imaging element according to [A03] satisfies 0 < X < 0.875, 0 < Y < 0.875, and 0.125 < Z < 0.875 (where X + Y + Z = 1.000).

[0588] [A05]<<Imaging element: Third aspect>>

[0589] An imaging element includes: a photoelectric conversion unit formed by laminating a first electrode, a photoelectric conversion layer, and a second electrode.

[0590] Between the first electrode and the photoelectric conversion layer, a composite oxide layer containing indium composite oxide is formed.

[0591] The composite oxide layer includes a first layer adjacent to the first electrode and a second layer adjacent to the photoelectric conversion layer, and

[0592] The first layer has a higher carrier mobility than the second layer.

[0593] [A06]The imaging element according to [A05] satisfies: 1×10 -6 ≤ (carrier mobility of the second layer) / (carrier mobility of the first layer) ≤ 0.1.

[0594] [A07]<<Imaging element: Fourth aspect>>

[0595] An imaging element includes: a photoelectric conversion unit formed by laminating a first electrode, a photoelectric conversion layer, and a second electrode, where

[0596] Between the first electrode and the photoelectric conversion layer, a composite oxide layer containing indium composite oxide is formed.

[0597] The composite oxide layer includes a first layer adjacent to the first electrode and a second layer adjacent to the photoelectric conversion layer, and

[0598] The first layer has a lower state density than the second layer. <00020​​​​​​The image pickup element according to any one of [A01] to [A08], wherein the photoelectric conversion unit further includes an insulating layer and a charge storage electrode, the charge storage electrode being provided separately from the first electrode and facing the complex oxide layer via the insulating layer.

[0602] [A10] The imaging element according to [A09] further includes a semiconductor substrate, wherein:

[0603] The photoelectric conversion unit is disposed above the semiconductor substrate.

[0604] [A11] The image pickup element according to [A09] or [A10], wherein the first electrode extends in an opening formed in the insulating layer and is connected to the complex oxide layer.

[0605] [A12] The image pickup element according to [A09] or [A10], wherein the complex oxide layer extends in an opening formed in the insulating layer and is connected to the first electrode.

[0606] [A13] The imaging element according to [A12], wherein:

[0607] The edge of the top surface of the first electrode is covered by the insulating layer,

[0608] The first electrode is exposed on the bottom surface of the opening, and

[0609] When the surface of the insulating layer in contact with the top surface of the first electrode is called the first surface, and the surface of the insulating layer in contact with the portion of the composite oxide layer facing the charge accumulation electrode is called the second surface, the side surface of the opening has a slope that widens from the first surface toward the second surface.

[0610] [A14] The image pickup element according to [A13], wherein the side surface of the opening having a slope that widens from the first surface toward the second surface is located on the charge storage electrode side.

[0611] [A15] <<Potential Control of the First Electrode and the Charge Accumulation Electrode>>

[0612] The imaging element according to any one of [A09] to [A14] further includes a control unit provided on the semiconductor substrate and having a drive circuit, wherein

[0613] the first electrode and the charge accumulation electrode are connected to the drive circuit,

[0614] During the charge accumulation period, the drive circuit sets the potential V 11applied to the first electrode, the potential V 12 applied to the charge accumulation electrode, and charge is accumulated in the composite oxide layer, and

[0615] During the charge transfer period, the driving circuit sets the potential V 21 applied to the first electrode, the potential V 22 The charge applied to the charge accumulation electrode and accumulated in the composite oxide layer is read out by the control unit via the first electrode.

[0616] However, in the case where the potential of the first electrode is higher than the potential of the second electrode, V 12 ≥V 11 And V 22 <V 21 ,and

[0617] When the potential of the first electrode is lower than the potential of the second electrode,

[0618] Meet V 12 ≤V 11 And V 22 >V 21 .

[0619] [A16]<<Transmission Control Electrode>>

[0620] The imaging element according to any one of [A09] to [A15] further includes a transfer control electrode located between the first electrode and the charge accumulation electrode, the transfer control electrode being arranged separately from the first electrode and the charge accumulation electrode and facing the composite oxide layer via the insulating layer.

[0621] [A17] <<Potential Control of the First Electrode, Charge Accumulation Electrode, and Transfer Control Electrode>>

[0622] The imaging element according to [A16] further includes a control unit provided on the semiconductor substrate and having a drive circuit, wherein:

[0623] The first electrode, the charge accumulation electrode, and the transfer control electrode are connected to the drive circuit,

[0624] During the charge accumulation period, the drive circuit sets the potential V 11 applied to the first electrode, the potential V 12 is applied to the charge accumulation electrode, and the potential V 13 applied to the transport control electrode, and charges are accumulated in the composite oxide layer, and

[0625] During the charge transfer period, the driving circuit sets the potential V 21 applied to the first electrode, the potential V 22 is applied to the charge accumulation electrode, and the potential V 23 Charges applied to the transfer control electrode and accumulated in the complex oxide layer are read out by the control unit through the first electrode.

[0626] However, in the case where the potential of the first electrode is higher than the potential of the second electrode,

[0627] Meet V 12 >V 13 And V 22 ≤V 23 ≤V 21 ,and

[0628] When the potential of the first electrode is lower than the potential of the second electrode,

[0629] Meet V 12 <V 13 And V 22 ≥V 23 ≥V 21 .

[0630] [A18] <<Charge Discharge Electrode>>

[0631] The image pickup element according to any one of [A09] to [A17] further includes a charge discharge electrode connected to the composite oxide layer and provided separately from the first electrode and the charge storage electrode.

[0632] [A19] The image pickup element according to [A18], wherein the charge discharge electrode is provided so as to surround the first electrode and the charge accumulation electrode.

[0633] [A20] The imaging element according to [A18] or [A19], wherein

[0634] The complex oxide layer extends in the second opening formed in the insulating layer and is connected to the charge discharge electrode,

[0635] The edge of the top surface of the charge discharge electrode is covered by the insulating layer,

[0636] The charge discharge electrode is exposed on the bottom surface of the second opening, and

[0637] When the surface of the insulating layer in contact with the top surface of the charge discharge electrode is called the third surface, and the surface of the insulating layer in contact with the portion of the composite oxide layer facing the charge accumulation electrode is called the second surface, the side surface of the second opening has a slope that widens from the third surface toward the second surface.

[0638] [A21] <<Potential Control of the First Electrode, the Charge Accumulation Electrode, and the Charge Discharge Electrode>>

[0639] The imaging element according to any one of [A18] to [A20] further includes a control unit provided on the semiconductor substrate and having a drive circuit, wherein:

[0640] The first electrode, the charge accumulation electrode, and the charge discharge electrode are connected to the drive circuit,

[0641] During the charge accumulation period, the drive circuit sets the potential V 11 applied to the first electrode, the potential V 12 is applied to the charge accumulation electrode, and the potential V 14 applied to the charge discharge electrode, and charges are accumulated in the composite oxide layer, and

[0642] During the charge transfer period, the driving circuit sets the potential V 21 applied to the first electrode, the potential V 22 is applied to the charge accumulation electrode, and the potential V 24 Charges applied to the charge discharge electrode and accumulated in the composite oxide layer are read out by the control unit through the first electrode.

[0643] However, in the case where the potential of the first electrode is higher than the potential of the second electrode, V 14 >V 11 And V 24 <V 21 ,and

[0644] When the potential of the first electrode is lower than the potential of the second electrode,

[0645] Meet V 14 <V 11 And V 24 >V 21 .

[0646] [A22] <<Charge Accumulation Electrode Section>>

[0647] The image pickup element according to any one of [A09] to [A21], wherein the charge accumulation electrode includes a plurality of charge accumulation electrode segments.

[0648] [A23] The imaging element according to [A22], wherein:

[0649] In the case where the potential of the first electrode is higher than the potential of the second electrode, in the charge transfer period, the potential applied to the charge accumulation electrode segment closest to the first electrode is higher than the potential applied to the charge accumulation electrode segment farthest from the first electrode, and

[0650] When the potential of the first electrode is lower than the potential of the second electrode, during the charge transfer period, the potential applied to the charge accumulation electrode segment closest to the first electrode is lower than the potential applied to the charge accumulation electrode segment farthest from the first electrode.

[0651] [A24] The imaging element according to any one of [A01] to [A23], wherein the thickness of the composite oxide layer is 2×10 -8 m to 1×10 -7 m.

[0652] [A25] The imaging element according to any one of [A01] to [A24], wherein

[0653] Light is incident from the second electrode,

[0654] The surface roughness Ra of the composite oxide layer at the interface between the photoelectric conversion layer and the composite oxide layer is 1.5 nm or less, and the root mean square roughness Rq of the composite oxide layer is 2.5 nm or less.

[0655] [A26] The imaging element according to any one of [A09] to [A25], wherein

[0656] On the semiconductor substrate, at least a floating diffusion layer and an amplifying transistor constituting a control unit are provided, and

[0657] The first electrode is connected to the floating diffusion layer and a gate portion of the amplifying transistor.

[0658] [A27] The imaging element according to [A26], wherein:

[0659] A reset transistor and a selection transistor constituting the control unit are further provided on the semiconductor substrate.

[0660] The floating diffusion layer is connected to a source / drain region of the reset transistor, and

[0661] One source / drain region of the amplifying transistor is connected to one source / drain region of the selecting transistor, and the other source / drain region of the selecting transistor is connected to a signal line.

[0662] [A28] The imaging element according to any one of [A09] to [A27], wherein the charge storage electrode is larger than the first electrode.

[0663] [A29] The image sensor according to any one of [A09] to [A28], wherein light is incident from the second electrode side, and the light shielding layer is formed on the light incident side of the second electrode.

[0664] [A30] The imaging element according to any one of [A09] to [A28], wherein light is incident from the second electrode side and light is not incident on the first electrode.

[0665] [A31] The imaging element according to [A30], wherein a light shielding layer is formed on the light incident side of the second electrode and above the first electrode.

[0666] [A32] The imaging element according to [A30], wherein:

[0667] An on-chip microlens is provided above the charge accumulation electrode and the second electrode, and

[0668] Light incident on the on-chip microlens is collected by the charge accumulation electrode.

[0669] [A33] <<Image Sensor: First Structure>>

[0670] The imaging element according to any one of [A09] to [A32], wherein

[0671] The photoelectric conversion unit includes N (where N≥2) photoelectric conversion unit segments,

[0672] The composite oxide layer and the photoelectric conversion layer include N photoelectric conversion layer segments,

[0673] The insulating layer includes N insulating layer segments,

[0674] The charge accumulation electrode comprises N charge accumulation electrode segments,

[0675] The nth (where n=1, 2, 3, . . . N) photoelectric conversion unit section includes the nth charge accumulation electrode section, the nth insulating layer section, and the nth photoelectric conversion layer section,

[0676] The photoelectric conversion unit segment with a larger n value is farther away from the first electrode, and

[0677] The thickness of the insulating layer section gradually changes from the first photoelectric conversion unit section to the Nth photoelectric conversion unit section.

[0678] [A34] <<Image Sensor: Second Structure>>

[0679] The imaging element according to any one of [A09] to [A32], wherein

[0680] The photoelectric conversion unit includes N (where N≥2) photoelectric conversion unit segments,

[0681] The composite oxide layer and the photoelectric conversion layer include N photoelectric conversion layer segments,

[0682] The insulating layer includes N insulating layer segments,

[0683] The charge accumulation electrode comprises N charge accumulation electrode segments,

[0684] The nth (where n=1, 2, 3 . . . N) photoelectric conversion unit section includes the nth charge accumulation electrode section, the nth insulating layer section, and the nth photoelectric conversion layer section.

[0685] The photoelectric conversion unit segment with a larger n value is farther away from the first electrode, and

[0686] The thickness of the photoelectric conversion layer section gradually changes from the first photoelectric conversion unit section to the Nth photoelectric conversion unit section.

[0687] [A35] <<Image Sensor: Third Structure>>

[0688] The imaging element according to any one of [A09] to [A32], wherein

[0689] The photoelectric conversion unit includes N (where N≥2) photoelectric conversion unit segments,

[0690] The composite oxide layer and the photoelectric conversion layer include N photoelectric conversion layer segments,

[0691] The insulating layer includes N insulating layer segments,

[0692] The charge accumulation electrode comprises N charge accumulation electrode segments,

[0693] The nth (where n=1, 2, 3 . . . N) photoelectric conversion unit section includes the nth charge accumulation electrode section, the nth insulating layer section, and the nth photoelectric conversion layer section.

[0694] The photoelectric conversion unit segment with a larger n value is farther away from the first electrode, and

[0695] For adjacent photoelectric conversion unit sections, the materials constituting the insulating layer sections are different.

[0696] [A36] <<Image Sensor: Fourth Structure>>

[0697] The imaging element according to any one of [A09] to [A32], wherein

[0698] The photoelectric conversion unit includes N (where N≥2) photoelectric conversion unit segments,

[0699] The composite oxide layer and the photoelectric conversion layer include N photoelectric conversion layer segments,

[0700] The insulating layer includes N insulating layer segments,

[0701] The charge accumulation electrode includes N separately arranged charge accumulation electrode segments,

[0702] The nth (where n=1, 2, 3 . . . N) photoelectric conversion unit section includes the nth charge accumulation electrode section, the nth insulating layer section, and the nth photoelectric conversion layer section.

[0703] The photoelectric conversion unit segment with a larger n value is farther away from the first electrode, and

[0704] The materials constituting the charge accumulation electrode section are different for adjacent photoelectric conversion unit sections.

[0705] [A37] <<Image Sensor: Fifth Structure>>

[0706] The imaging element according to any one of [A09] to [A32], wherein

[0707] The photoelectric conversion unit includes N (where N≥2) photoelectric conversion unit segments,

[0708] The composite oxide layer and the photoelectric conversion layer include N photoelectric conversion layer segments,

[0709] The insulating layer includes N insulating layer segments,

[0710] The charge accumulation electrode includes N separately arranged charge accumulation electrode segments,

[0711] The nth (where n=1, 2, 3 . . . N) photoelectric conversion unit section includes the nth charge accumulation electrode section, the nth insulating layer section, and the nth photoelectric conversion layer section.

[0712] The photoelectric conversion unit segment with a larger n value is farther away from the first electrode, and

[0713] The area of ​​the charge accumulation electrode section gradually decreases from the first photoelectric conversion unit section to the Nth photoelectric conversion unit section.

[0714] [A38] <<Image Sensor: Sixth Structure>>

[0715] An imaging element according to any one of [A09] to [A32], wherein, if the stacking direction of the charge accumulation electrode, the insulating layer, the composite oxide layer and the photoelectric conversion layer is defined as the Z direction, and the direction of separation from the first electrode is defined as the X direction, then when the stacking portion on which the charge accumulation electrode, the insulating layer, the composite oxide layer and the photoelectric conversion layer are stacked is cut with a YZ imaginary plane, the cross-sectional area of ​​the stacking portion changes depending on the distance from the first electrode.

[0716] [B01] <<Stacked Imaging Element>>

[0717] A stacked imaging element including at least one imaging element according to any one of [A01] to [A38].

[0718] [C01] <<Solid-state imaging device: First aspect>>

[0719] A solid-state imaging device comprising a plurality of imaging elements according to any one of [A01] to [A38].

[0720] [C02] <<Solid-state imaging device: Second aspect>>

[0721] A solid-state imaging device comprising a plurality of stacked imaging elements according to [B01].

[0722] [D01] <<Solid-state imaging device: First structure>>

[0723] A solid-state imaging device comprising: a photoelectric conversion unit formed by stacking a first electrode, a photoelectric conversion layer, and a second electrode, wherein

[0724] The photoelectric conversion unit includes a plurality of imaging elements according to any one of [A01] to [A38],

[0725] The plurality of imaging elements constitute an imaging element block, and

[0726] The first electrode is shared by the plurality of imaging elements constituting the imaging element block.

[0727] [D02] <<Solid-state imaging device: Second structure>>

[0728] A solid-state imaging device comprising a plurality of imaging elements according to any one of [A01] to [A38],

[0729] The plurality of imaging elements constitute an imaging element block, and

[0730] The first electrode is shared by the plurality of imaging elements constituting the imaging element block.

[0731] [D03] The solid-state imaging device according to [D01] or [D02], wherein one on-chip microlens is provided above one of the imaging elements.

[0732] [D04] The solid-state imaging device according to [D01] or [D02], wherein

[0733] The two imaging elements constitute an imaging element block, and

[0734] An on-chip microlens is disposed above the image pickup element block.

[0735] [D05] The solid-state imaging device according to any one of [D01] to [D04], wherein one floating diffusion layer is provided for each of the plurality of imaging elements.

[0736] [D06] The solid-state imaging device according to any one of [D01] to [D05], wherein the first electrode is provided adjacent to the charge storage electrode of each of the imaging elements.

[0737] [D07] A solid-state imaging device according to any one of [D01] to [D06], wherein the first electrode is arranged adjacent to some of the charge accumulation electrodes in the multiple imaging elements, and is not arranged adjacent to the remaining charge accumulation electrodes in the multiple imaging elements.

[0738] [D08] A solid-state imaging device according to [D07], wherein the distance between the charge accumulation electrodes constituting the imaging element and the charge accumulation electrodes constituting the imaging element is longer than the distance between the first electrode and the charge accumulation electrode in the imaging element adjacent to the first electrode.

[0739] [E01]<<Driving Method of Solid-State Image Capture Device>>

[0740] A method for driving a solid-state imaging device, the solid-state imaging device including a plurality of imaging elements according to any one of [A01] to [A38], each of the imaging elements having a structure in which light is incident from the second electrode side and light is not incident on the first electrode, wherein:

[0741] The method repeats the following steps:

[0742] In all the imaging elements, while accumulating charges in the composite oxide layer, all the charges in the first electrode are simultaneously released to the outside of the system, and then

[0743] In all the imaging elements, all the charges accumulated in the complex oxide layer are transferred to the first electrode at the same time, and after the transfer is completed, the charges transferred to the first electrode are sequentially read in each of the imaging elements.

[0744] Reference Signs List

[0745] 10'1, 10'2, 10'3 photoelectric conversion unit sections

[0746] 13 Various camera components located below the interlayer insulating layer

[0747] 14 On-chip microlenses (OCL)

[0748] 15. Light-shielding layer

[0749] 21 First electrode

[0750] 22 Second electrode

[0751] 23A Photoelectric conversion layer

[0752] 23B composite oxide layer

[0753] The first layer of the 23B1 composite oxide layer

[0754] The second layer of 23B2 composite oxide layer

[0755] 23'1, 23'2, 23'3 Photoelectric conversion layer sections

[0756] 24, 24"1, 24"2, 24"3 charge accumulation electrodes

[0757] 24A, 24B, 24C, 24'1, 24'2, 24'3 charge accumulation electrode segments

[0758] 25, 25A, 25B transfer control electrodes (charge transfer electrodes)

[0759] 26 Charge discharge electrode

[0760] 27,27A1,27A2,27A3,27B1,27B2,27B3,27C Charge transfer control electrodes

[0761] 31,33,41,43n-type semiconductor regions

[0762] 32,34,42,44,73p + layer

[0763] 35,36,45,46 Gate portion of the transfer transistor

[0764] 35C, 36C semiconductor substrate area

[0765] 36A transmission channel

[0766] 51 Reset transistor TR1 rst Gate

[0767] 51A reset transistor TR1 rst Channel formation region

[0768] 51B, 51C reset transistor TR1 rst Source / drain regions

[0769] 52 amplifier transistor TR1 amp Gate

[0770] 52A amplifier transistor TR1 amp Channel formation region

[0771] 52B, 52C amplifier transistor TR1 amp Source / drain regions

[0772] 53 select transistor TR1 sel Gate

[0773] 53A selection transistor TR1 sel Channel formation region

[0774] 53B, 53C select transistor TR1 sel Source / drain regions

[0775] 61 Contact hole part

[0776] 62 wiring layer

[0777] 63,64,68A pads

[0778] 65,66,68B connection holes

[0779] 67,69 connection

[0780] 70 semiconductor substrate

[0781] 70A: first surface (front surface) of semiconductor substrate

[0782] 70B: second side (back side) of semiconductor substrate

[0783] 71 Component separation area

[0784] 72 oxide film

[0785] 74HfO2 film

[0786] 75 insulation material film

[0787] 76,81 interlayer insulation layer

[0788] 82 insulation layer

[0789] 82'1,82'2,82'3 insulation layer sections

[0790] 82a First surface of the insulating layer

[0791] 82b second surface of the insulating layer

[0792] 82c Third surface of the insulating layer

[0793] 83 insulation layer

[0794] 85,85A,85B,85C opening

[0795] 86,86A second opening

[0796] 100 Solid-state imaging device

[0797] 101 Stacked Image Sensor

[0798] 111 Camera Area

[0799] 112 vertical drive circuit

[0800] 113 column signal processing circuit

[0801] 114 Horizontal drive circuit

[0802] 115 Output Circuit

[0803] 116 drive control circuit

[0804] 117 signal line (data output line)

[0805] 118 horizontal signal lines

[0806] 200 Electronic equipment (camera)

[0807] 201 Solid-state imaging device

[0808] 210 optical lens

[0809] 211 Shutter mechanism

[0810] 212 drive circuit

[0811] 213 signal processing circuit

[0812] FD1, FD2, FD3, 45C, 46C floating diffusion layer

[0813] TR1 trs ,TR2 trs ,TR3 trs Pass transistor

[0814] TR1 rst ,TR2 rst ,TR3 rst Reset transistor

[0815] TR1 amp ,TR2 amp ,TR3 amp Amplifier transistor

[0816] TR1 sel ,TR3 sel ,TR3 sel Select transistor

[0817] VDD power supply

[0818] TG1, TG2, TG3 transmission gate lines

[0819] RST1, RST2, RST3 reset lines

[0820] SEL1, SEL2, SEL3 selection lines

[0821] VSL, VSL1, VSL2, VSL3 signal lines (data output lines)

[0822] V OA ,V OT ,V OU Wiring

Claims

1. A light detection element, comprising a photoelectric conversion unit, wherein the photoelectric conversion unit comprises: a first electrode; a second electrode; a photoelectric conversion layer, the photoelectric conversion layer being disposed between the first electrode and the second electrode; as well as a composite oxide layer, the composite oxide layer comprising an indium composite oxide disposed between the first electrode and the photoelectric conversion layer, the composite oxide layer comprising a first layer and a second layer, wherein the first layer is disposed between the first electrode and the second layer, and The ratio of the carrier mobility of the second layer to the carrier mobility of the first layer is greater than or equal to 1×10 -6 , and is less than or equal to 0.

1.

2. The light detecting element according to claim 1, wherein The composite oxide layer is amorphous.

3. The light detecting element according to claim 1, wherein The photoelectric conversion unit further includes an insulating layer and a charge accumulation electrode provided separately from the first electrode and facing the complex oxide layer via the insulating layer.

4. The light detecting element according to claim 1, wherein The thickness of the composite oxide layer is 2×10 -8 m to 1×10 -7 m.

5. The light detecting element according to claim 1, wherein Light is incident from the second electrode, The surface roughness Ra of the composite oxide layer at the interface between the photoelectric conversion layer and the composite oxide layer is 1.5 nm or less, and the value of the root mean square roughness Rq of the composite oxide layer is 2.5 nm or less.

Images