Light detection device

Abstract

A light detection device according to an embodiment of the present disclosure comprises: a photoelectric conversion layer; a first electrode provided on one surface side of the photoelectric conversion layer, the first electrode including a charge storage electrode capable of storing charge carriers generated by photoelectric conversion and a charge reading electrode that is set apart from the charge storage electrode and that reads the charge carriers; an oxide semiconductor layer provided between the photoelectric conversion layer and the first electrode; a protective layer provided between the photoelectric conversion layer and the oxide semiconductor layer, the protective layer, at least above the charge storage electrode, having a lesser film thickness than the other regions and having an opening; and a second electrode provided on the other surface side of the photoelectric conversion layer, which is on opposite side to the one surface.

Description

Photodetector

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

[0002] For example, Patent Document 1 discloses an imaging element in which, in a photoelectric conversion section formed by stacking a first electrode, a photoelectric conversion layer made of an organic material, and a second electrode, an oxide semiconductor layer and an oxide film are formed between the first electrode and the photoelectric conversion layer from the first electrode side.

[0003] International Publication No. 2020 / 017330

[0004] Incidentally, there is a demand for improved sensitivity in photodetection devices that are also used as imaging devices.

[0005] It would be desirable to provide a photodetector device that can improve reliability.

[0006] A photodetector according to one embodiment of the present disclosure includes a photoelectric conversion layer, a first electrode provided on one surface of the photoelectric conversion layer, the first electrode including a charge storage electrode capable of storing charge carriers generated by photoelectric conversion and a charge readout electrode spaced apart from the charge storage electrode and configured to read out the charge carriers, an oxide semiconductor layer provided between the photoelectric conversion layer and the first electrode, a protective layer provided between the photoelectric conversion layer and the oxide semiconductor layer, the protective layer having an opening at least above the charge storage electrode that makes the protective layer thinner than other regions, and a second electrode provided on the other surface of the photoelectric conversion layer opposite to the one surface.

[0007] In one embodiment of the photodetector according to the present disclosure, a first electrode including a charge storage electrode and a charge readout electrode and a second electrode are disposed at a distance from each other, and an oxide semiconductor layer, a protective layer, and a photoelectric conversion layer are stacked between the first electrode and the second electrode in this order. The protective layer has an opening at least above the charge storage electrode, which makes the protective layer thinner than other regions. This prevents the formation of oxygen defects in the oxide semiconductor layer without impeding the movement of charge carriers generated by photoelectric conversion to the oxide semiconductor layer.

[0008] FIG. 1 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view schematically illustrating an example of a planar configuration of a photodetector device including the photodetector shown in FIG. 1. FIG. 3 is a cross-sectional view schematically illustrating an example of a pixel configuration of the photodetector shown in FIG. 1. FIG. 4 is a cross-sectional view schematically illustrating an example of a configuration of a photoelectric conversion unit shown in FIG. 1. FIG. 5 is a diagram illustrating an example of energy levels of each layer on a storage electrode in an opening of the photoelectric conversion unit shown in FIG. 4. FIG. 6 is a diagram illustrating an example of energy levels of each layer on a storage electrode in a non-opening of the photoelectric conversion unit shown in FIG. 4. FIG. 7 is a cross-sectional view schematically illustrating another example of the configuration of the photoelectric conversion unit shown in FIG. 1. FIG. 8 is a diagram illustrating an example of energy levels of each layer on a storage electrode in an opening of the photoelectric conversion unit shown in FIG. 7. FIG. 9 is an equivalent circuit diagram of the photodetector shown in FIG. 1. FIG. 11 is a cross-sectional view for explaining a method for manufacturing the photodetector shown in FIG. 3. FIG. 12 is a cross-sectional view illustrating a process subsequent to FIG. 11. FIG. 13 is a cross-sectional view illustrating a step subsequent to FIG. 12 . FIG. 14 is a cross-sectional view illustrating a step subsequent to FIG. 13 . FIG. 15 is a cross-sectional view illustrating a step subsequent to FIG. 14 . FIG. 16 is a cross-sectional view illustrating a step subsequent to FIG. 15 . FIG. 17 is a timing chart illustrating an example of an operation of the photodetector element illustrated in FIG. 1 . FIG. 18 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector element according to Modification 1 of the present disclosure. FIG. 19 is a plan view schematically illustrating an example of a pixel configuration of the photodetector element illustrated in FIG. 18 . FIG. 20 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector element according to Modification 2 of the present disclosure. FIG. 21 is a plan view schematically illustrating an example of a pixel configuration of the photodetector element illustrated in FIG. 20 . FIG. 22 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector element according to Modification 3 of the present disclosure. FIG. 23 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector element according to Modification 4 of the present disclosure. FIG. 24 is a cross-sectional view schematically illustrating an example of a configuration of a photodetector element according to Modification 5 of the present disclosure. FIG. 25 is a plan view schematically illustrating an example of a pixel configuration of the photodetector element illustrated in FIG. 24 . Fig. 26 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 6 of the present disclosure. Fig. 27 is a schematic plan view illustrating an example of the pixel configuration of the photodetector shown in Fig. 26 .FIG. 28 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 7 of the present disclosure. FIG. 29 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 28 . FIG. 30 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the non-opening of the photoelectric conversion unit shown in FIG. 28 . FIG. 31 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 8 of the present disclosure. FIG. 32 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 31 . FIG. 33 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the non-opening of the photoelectric conversion unit shown in FIG. 31 . FIG. 34 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 9 of the present disclosure. FIG. 35 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 10 of the present disclosure. FIG. 36 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 11 of the present disclosure. FIG. 37 is a schematic plan view illustrating an example of the pixel configuration of the photodetector shown in FIG. 36 . FIG. 38 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector element according to Modification 12 of the present disclosure. FIG. 39 is a schematic cross-sectional view illustrating another example of the configuration of a photodetector element according to Modification 12 of the present disclosure. FIG. 40 is a schematic cross-sectional view illustrating an example of the configuration of a photoelectric conversion unit, which is a main part of a photodetector element according to a second embodiment of the present disclosure. FIG. 41 is a schematic plan view illustrating an example of a pixel configuration of the photodetector element shown in FIG. 40. FIG. 42 is a diagram illustrating an example of energy levels of each layer on a storage electrode in an opening portion of the photoelectric conversion unit shown in FIG. 40. FIG. 43 is a diagram illustrating an example of energy levels of each layer on a storage electrode in a non-opening portion of the photoelectric conversion unit shown in FIG. 40. FIG. 44 is a schematic plan view illustrating another example of the pixel configuration of the photodetector element shown in FIG. 40. FIG. 45 is a schematic plan view illustrating another example of the pixel configuration of the photodetector element shown in FIG. 40. FIG. 46 is a schematic plan view illustrating another example of the pixel configuration of the photodetector element shown in FIG. 40. Fig. 47 is a cross-sectional view schematically illustrating an example of the configuration of a photodetector element according to Modification 13 of the present disclosure. Fig. 48 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in Fig. 47. Fig. 49 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the non-opening of the photoelectric conversion unit shown in Fig. 47.FIG. 50 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 14 of the present disclosure. FIG. 51 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 50 . FIG. 52 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the non-opening of the photoelectric conversion unit shown in FIG. 50 . FIG. 53 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 15 of the present disclosure. FIG. 54 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 53 . FIG. 55 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the non-opening of the photoelectric conversion unit shown in FIG. 53 . FIG. 56 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 16 of the present disclosure. FIG. 57 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 55 . FIG. 58 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the non-opening of the photoelectric conversion unit shown in FIG. 55 . FIG. 59 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 17 of the present disclosure. FIG. 60 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 59 . FIG. 61 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the non-opening of the photoelectric conversion unit shown in FIG. 59 . FIG. 62 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 18 of the present disclosure. FIG. 63 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 62 . FIG. 64 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the non-opening of the photoelectric conversion unit shown in FIG. 62 . FIG. 65 is a schematic cross-sectional view illustrating an example of the configuration of a photoelectric conversion unit that is a main part of a photodetector according to a third embodiment of the present disclosure. FIG. 66 is a schematic plan view illustrating an example of the pixel configuration of the photodetector shown in FIG. 65 . FIG. 67 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 19 of the present disclosure. Fig. 68 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 20 of the present disclosure. Fig. 69 is a schematic cross-sectional view showing an example of the configuration of a photodetector according to Modification 21 of the present disclosure. Fig. 70 is a schematic plan view showing an example of the pixel configuration of the photodetector shown in Fig. 69 .FIG. 71 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 22 of the present disclosure. FIG. 72 is a schematic plan view illustrating an example of the pixel configuration of the photodetector shown in FIG. 71. FIG. 73 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 23 of the present disclosure. FIG. 74 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 73. FIG. 75 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the non-opening of the photoelectric conversion unit shown in FIG. 73. FIG. 76 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 24 of the present disclosure. FIG. 77 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 76. FIG. 78 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 25 of the present disclosure. FIG. 79 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 78. FIG. 80 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 26 of the present disclosure. FIG. 81 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 80 . FIG. 82 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 27 of the present disclosure. FIG. 83 is a schematic plan view illustrating an example of the pixel configuration of the photodetector shown in FIG. 82 . FIG. 84 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 82 . FIG. 85 is a diagram illustrating an example of the energy levels of each layer on the shield electrode in the non-opening of the photoelectric conversion unit shown in FIG. 82 . FIG. 86 is a diagram illustrating an example of the energy levels of each layer on the shield electrode in the non-opening of the photoelectric conversion unit as a comparative example. FIG. 87 is a schematic cross-sectional view illustrating an example of the configuration of a photodetector according to Modification 28 of the present disclosure. FIG. 88 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in FIG. 87 . FIG. 89 is a diagram illustrating an example of the energy levels of each layer on the shield electrode in the non-opening of the photoelectric conversion unit shown in FIG. 87 . Fig. 90 is a cross-sectional view schematically illustrating an example of the configuration of a photodetector element according to Modification 29 of the present disclosure. Fig. 91 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening of the photoelectric conversion unit shown in Fig. 90.92 is a diagram illustrating an example of the energy levels of each layer on the shield electrode in the non-opening portion of the photoelectric conversion unit shown in FIG. 90 . FIG. 93 is a cross-sectional schematic diagram illustrating an example of the configuration of a photodetector according to Modification 30 of the present disclosure. FIG. 94 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening portion of the photoelectric conversion unit shown in FIG. 93 . FIG. 95 is a diagram illustrating an example of the energy levels of each layer on the shield electrode in the non-opening portion of the photoelectric conversion unit shown in FIG. 93 . FIG. 96 is a cross-sectional schematic diagram illustrating an example of the configuration of a photodetector according to Modification 31 of the present disclosure. FIG. 97 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening portion of the photoelectric conversion unit shown in FIG. 96 . FIG. 98 is a diagram illustrating an example of the energy levels of each layer on the shield electrode in the non-opening portion of the photoelectric conversion unit shown in FIG. 96 . FIG. 99 is a cross-sectional schematic diagram illustrating an example of the configuration of a photodetector according to Modification 32 of the present disclosure. FIG. 100 is a diagram illustrating an example of the energy levels of each layer on the storage electrode in the opening portion of the photoelectric conversion unit shown in FIG. 99 . FIG. 101 is a diagram showing an example of energy levels of each layer on a shield electrode in a non-opening portion of the photoelectric conversion unit shown in FIG. 99 . FIG. 102A is a cross-sectional schematic diagram showing an example of a configuration of a photodetector according to Other Modification 1 of the present disclosure. FIG. 102B is a planar schematic diagram showing an example of a pixel configuration of a photodetector including the photodetector shown in FIG. 102A . FIG. 103A is a cross-sectional schematic diagram showing another example of a configuration of a photodetector according to Other Modification 2 of the present disclosure. FIG. 103B is a planar schematic diagram showing an example of a pixel configuration of a photodetector including the photodetector shown in FIG. 103A . FIG. 104 is a cross-sectional schematic diagram showing another example of a configuration of a photodetector according to Other Modification 3 of the present disclosure. FIG. 105 is a schematic diagram showing another example of a configuration of a photodetector according to Other Modification 4 of the present disclosure. FIG. 106A is a cross-sectional schematic diagram showing another example of a configuration of a photodetector according to Other Modification 5 of the present disclosure. FIG. 106B is a planar schematic diagram showing an example of a pixel configuration of a photodetector including the photodetector shown in FIG. 106A . Fig. 107A is a cross-sectional view schematically illustrating another example of the configuration of a photodetector according to Modification Example 6 of the present disclosure. Fig. 107B is a plan view schematically illustrating an example of the pixel configuration of a photodetector device having the photodetector shown in Fig. 107A.FIG. 108 is a cross-sectional schematic diagram illustrating another example of the configuration of a photodetector according to Variation 7 of the present disclosure. FIG. 109 is a block diagram illustrating the overall configuration of a photodetector including the photodetector shown in FIG. 1, etc. FIG. 110 is a block diagram illustrating an example of the configuration of an electronic device using the photodetector shown in FIGS. 10 and 1109. FIG. 111A is a schematic diagram illustrating an example of the overall configuration of a photodetection system using the photodetector shown in FIG. 109. FIG. 111B is a diagram illustrating an example of the circuit configuration of the photodetection system shown in FIG. 111A. FIG. 112 is a diagram illustrating an example of a schematic configuration of an endoscopic surgery system. FIG. 113 is a block diagram illustrating an example of the functional configuration of a camera head and a CCU. FIG. 114 is a block diagram illustrating an example of a schematic configuration of a vehicle control system. FIG. 115 is an explanatory diagram illustrating an example of the installation positions of an outside vehicle information detection unit and an imaging unit. FIG. 116 is a cross-sectional schematic diagram illustrating an example of the configuration of a photodetector according to a fourth embodiment of the present disclosure. FIG. 117 is a schematic diagram illustrating an example of the planar configuration of a photodetector including the photodetector shown in FIG. 116. FIG. 118 is an equivalent circuit diagram of the photodetector element shown in FIG. 116. FIG. 119A is a schematic diagram showing an example of the cross-sectional shape of the protective film shown in FIG. 116. FIG. 119B is a schematic diagram showing another example of the cross-sectional shape of the protective film shown in FIG. 116. FIG. 119C is a schematic diagram showing another example of the cross-sectional shape of the protective film shown in FIG. 116. FIG. 119D is a schematic diagram showing another example of the cross-sectional shape of the protective film shown in FIG. 116. FIG. 119E is a schematic diagram showing another example of the cross-sectional shape of the protective film shown in FIG. 116. FIG. 120A is a cross-sectional view for explaining a method for manufacturing the overhanging-type protective layer shown in FIG. 119B. FIG. 120B is a cross-sectional view showing a step subsequent to FIG. 120A. FIG. 120C is a cross-sectional view showing a step subsequent to FIG. 120B. FIG. 120D is a cross-sectional view showing a step subsequent to FIG. 120C. FIG. 120E is a cross-sectional view showing a step subsequent to FIG. 120D. FIG. 120F is a cross-sectional view showing a step subsequent to FIG. 120E. Fig. 120G is a cross-sectional view showing a step subsequent to Fig. 120F. Fig. 121 is a cross-sectional schematic view showing an example of a configuration of a photodetector according to Modification 33 of the present disclosure. Fig. 122 is a plan schematic view showing an example of a pixel configuration of the photodetector shown in Fig. 121.

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspects. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of each component shown in each drawing. The description will be made in the following order. 1. First embodiment (an example of a photodetector element in which a protective layer having an opening above a storage electrode is provided between an oxide semiconductor layer and a photoelectric conversion layer) 2. Modifications 2-1. Modification 1 (another example of the configuration of the photoelectric conversion section) 2-2. Modification 2 (another example of the configuration of the photoelectric conversion section) 2-3. Modification 3 (another example of the configuration of the photoelectric conversion section) 2-4. Modification 4 (another example of the configuration of the photoelectric conversion section) 2-5. Modification 5 (another example of the configuration of the photoelectric conversion section) 2-6. Modification 6 (another example of the configuration of the photoelectric conversion section) 2-7. Modification 7 (another example of the configuration of the photoelectric conversion section) 2-8. Modification 8 (another example of the configuration of the photoelectric conversion section) 2-9. 1. Modification 9 (Another Example of the Configuration of the Photoelectric Conversion Section) 2-10. Modification 10 (Another Example of the Configuration of the Photoelectric Conversion Section) 2-11. Modification 11 (Another Example of the Configuration of the Photoelectric Conversion Section) 2-12. Modification 12 (Another Example of the Configuration of the Photoelectric Conversion Section) 3. Second Embodiment (Example of a Photodetector in which an Electron Transport Layer is Further Provided on a Protective Layer Provided Between an Oxide Semiconductor Layer and a Photoelectric Conversion Layer and Having an Opening Above a Storage Electrode) 4. Modifications 4-1. Modification 13 (Another Example of the Configuration of the Photoelectric Conversion Section) 4-2. Modification 14 (Another Example of the Configuration of the Photoelectric Conversion Section) 4-3. Modification 15 (Another Example of the Configuration of the Photoelectric Conversion Section) 4-5. Modification 16 (Another Example of the Configuration of the Photoelectric Conversion Section) 4-5. Modification 17 (Another Example of the Configuration of the Photoelectric Conversion Section) 4-6. Modification 18 (Another Example of the Configuration of the Photoelectric Conversion Section) 5. Third embodiment (an example of a photodetector element in which the photoelectric conversion layer on the non-opening portion of a protective layer having openings and non-openings provided between an oxide semiconductor layer and a photoelectric conversion layer is insulated) 6. Modifications 6-1. Modification 19 (another example of the configuration of the photoelectric conversion section) 6-2. Modification 20 (another example of the configuration of the photoelectric conversion section) 6-3. Modification 21 (another example of the configuration of the photoelectric conversion section) 6-4. Modification 22 (another example of the configuration of the photoelectric conversion section) 7. Modifications7-1. Modification 23 (Another Example of the Configuration of the Photoelectric Conversion Section) 7-2. Modification 24 (Another Example of the Configuration of the Photoelectric Conversion Section) 7-3. Modification 25 (Another Example of the Configuration of the Photoelectric Conversion Section) 7-4. Modification 26 (Another Example of the Configuration of the Photoelectric Conversion Section) 7-5. Modification 27 (Another Example of the Configuration of the Photoelectric Conversion Section) 7-6. Modification 28 (Another Example of the Configuration of the Photoelectric Conversion Section) 7-7. Modification 29 (Another Example of the Configuration of the Photoelectric Conversion Section) 7-8. Modification 30 (Another Example of the Configuration of the Photoelectric Conversion Section) 7-9. Modification 31 (Another Example of the Configuration of the Photoelectric Conversion Section) 7-10. Modification 32 (Another Example of the Configuration of the Photoelectric Conversion Section) 8. Other Modifications 8-1. Other Modification 1 (Another Example of the Configuration of the Photoelectric Conversion Element) 8-2. Other Modification 2 (Another Example of the Configuration of the Photoelectric Conversion Element) 8-3. Other Modification 3 (Another Example of the Configuration of the Photoelectric Conversion Element) 8-4. Other Modifications 4 to 7 (other examples of the configuration of the photoelectric conversion element) 9. Fourth embodiment (example of a photodetector element in which the charge transport layer is discontinuous between the opening and non-opening portions of the protective film) 10. Modification 33 (other example of the configuration of the photoelectric conversion portion) 11. Application example 12. Application example

[0010] 1. First Embodiment FIG. 1 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector element (photodetector element 1) according to a first embodiment of the present disclosure. FIG. 2 is a schematic diagram illustrating an example of a planar configuration of a photodetector device 100 including the photodetector element 1 illustrated in FIG. 1. FIG. 3 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of the photodetector device 100 including the photodetector element 1 illustrated in FIG. 1. FIG. 1 illustrates a cross section corresponding to line II-II illustrated in FIG. 3. FIG. 4 is an enlarged schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 10) of the photodetector element illustrated in FIG. 1 and a boundary between a pixel unit 100A and a peripheral unit 100B, and illustrates a cross section corresponding to line II-II illustrated in FIG. 2. The photodetector element 1 constitutes one pixel (unit pixel P) repeatedly arranged in an array in a pixel section 100A of a photodetector device (e.g., photodetector device 100, see FIG. 109 ) such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor used in electronic devices such as digital still cameras and video cameras. In the pixel section 100A, as shown in FIG. 3 , a pixel unit 1a consisting of four unit pixels P arranged in, for example, two rows and two columns serves as a repeating unit, and is repeatedly arranged in an array consisting of row and column directions.

[0011] The photodetector element 1 of this embodiment has an oxide semiconductor layer 13, a protective layer 14, and a photoelectric conversion layer 15 stacked in this order from the lower electrode 11 side between a lower electrode 11 and an upper electrode 16. The lower electrode 11 includes a storage electrode 11B that can store charge carriers generated by photoelectric conversion and a readout electrode 11A that reads out the charge carriers, which are arranged spaced apart from each other. In this embodiment, the protective layer 14 has an opening X1 above at least the storage electrode 11B, making the protective layer 14 thinner than other regions.

[0012] Here, the photoelectric conversion layer 15 corresponds to a specific example of a "photoelectric conversion layer" according to an embodiment of the present disclosure. The lower electrode 11 corresponds to a specific example of a "first electrode" according to an embodiment of the present disclosure. The storage electrode 11B corresponds to a specific example of a "charge storage electrode" according to an embodiment of the present disclosure, and the readout electrode 11A corresponds to a specific example of a "charge readout electrode" according to an embodiment of the present disclosure. The upper electrode 16 corresponds to a specific example of a "second electrode" according to an embodiment of the present disclosure. The oxide semiconductor layer 13 corresponds to a specific example of an "oxide semiconductor layer" according to an embodiment of the present disclosure. The protective layer 14 corresponds to a specific example of a "protective layer" according to an embodiment of the present disclosure, and the opening X1 corresponds to a specific example of an "opening" according to an embodiment of the present disclosure.

[0013] [Configuration of Photodetector] The photodetector 1 is a so-called vertical spectroscopic photodetector in which, for example, one photoelectric conversion unit 10 and two photoelectric conversion regions 32B, 32R are stacked vertically. The photoelectric conversion unit 10 is provided on the back surface (first surface 30A) of the semiconductor substrate 30. The photoelectric conversion regions 32B, 32R are embedded in the semiconductor substrate 30 and stacked in the thickness direction of the semiconductor substrate 30.

[0014] The photoelectric conversion unit 10 and the photoelectric conversion regions 32B and 32R selectively detect light in different wavelength ranges and perform photoelectric conversion. For example, the photoelectric conversion unit 10 acquires a green (G) color signal. The photoelectric conversion regions 32B and 32R acquire blue (B) and red (R) color signals, respectively, due to differences in absorption coefficients. This allows the photodetector 1 to acquire multiple types of color signals in one pixel without using color filters.

[0015] In this embodiment, a case where electrons, among pairs of electrons and holes (excitons) generated by photoelectric conversion, are read out as signal charges (when an n-type semiconductor region is used as the photoelectric conversion layer) will be described. In addition, in the figures, a "+ (plus)" attached to "p" and "n" indicates that the p-type or n-type impurity concentration is high.

[0016] The semiconductor substrate 30 is, for example, an n-type silicon (Si) substrate and has a p-well 31 in a predetermined region. The surface (second surface 30B) of the semiconductor substrate 30 is provided with, for example, floating diffusions FD1 (region 36B within the semiconductor substrate 30), FD2 (region 37C within the semiconductor substrate 30), and FD3 (region 38C within the semiconductor substrate 30), transfer transistors Tr2 and Tr3, an amplifier transistor (modulation element) AMP, a reset transistor RST, and a select transistor SEL. The second surface 30B of the semiconductor substrate 30 is further provided with a multilayer wiring layer 40 via a gate insulating layer 33. The multilayer wiring layer 40 has, for example, a configuration in which wiring layers 41, 42, and 43 are stacked within an insulating layer 44. A vertical drive circuit 111, a column signal processing circuit 112, a horizontal drive circuit 113, an output circuit 114, a control circuit 115, an input / output terminal 116, etc., which will be described later, are provided around the periphery of the semiconductor substrate 30, i.e., around the pixel section 100A.

[0017] Between the rear surface (first surface 30A) of the semiconductor substrate 30 and the photoelectric conversion unit 10, for example, a layer that holds a fixed charge (fixed charge layer 21), a dielectric layer 22 having insulating properties, and an interlayer insulating layer 23 are stacked in this order from the first surface 30A side of the semiconductor substrate 30. Between the first surface 30A and the second surface 30B of the semiconductor substrate 30, a through electrode 34 is provided.

[0018] An optical member such as an on-chip lens 52 is disposed above the photoelectric conversion unit 10 with a protective layer 51 in between. Within the protective layer 51, for example, wiring 53 is provided that electrically connects the upper electrode 16 and the peripheral circuit unit around the pixel unit 100A.

[0019] In the drawings, the first surface 30A side of the semiconductor substrate 30 is shown as the light incident surface S1 side, and the second surface 30B side is shown as the wiring layer side S2.

[0020] In the photodetector element 1, light incident on the photoelectric conversion unit 10 from the light incident surface S1 side is absorbed by the photoelectric conversion layer 15. The excitons thus generated move to the interface between the electron donors and electron acceptors that make up the photoelectric conversion layer 15, where they undergo exciton dissociation, i.e., dissociation into electrons and holes. The charge carriers (electrons and holes) generated here are transported to different electrodes by diffusion due to differences in carrier concentration and an internal electric field due to the difference in work function between the anode (e.g., upper electrode 16) and the cathode (e.g., lower electrode 11), and are detected as photocurrent. The transport direction of the electrons and holes can also be controlled by applying a potential between the lower electrode 11 and the upper electrode 16.

[0021] The structure and materials of each part will be described in detail below.

[0022] The photoelectric conversion unit 10 is an organic photoelectric conversion element that absorbs, for example, green light corresponding to part or all of a selective wavelength range (e.g., 450 nm or more and 650 nm or less) and generates excitons. The photoelectric conversion unit 10 includes a lower electrode 11, an insulating layer 12, an oxide semiconductor layer 13, a protective layer 14, a photoelectric conversion layer 15, and an upper electrode 16 stacked in this order from the semiconductor substrate 30 side. The photoelectric conversion layer 15 includes, for example, a p-type semiconductor and an n-type semiconductor, and has a bulk heterojunction structure within the layer. The bulk heterojunction structure is a p / n junction surface formed by mixing a p-type semiconductor and an n-type semiconductor.

[0023] The lower electrode 11 has, for example, a read electrode 11A and a storage electrode 11B arranged in parallel on an interlayer insulating layer 23 .

[0024] The readout electrode 11A is for transferring, for example, electrons as signal charges among the charge carriers generated in the photoelectric conversion layer 15 to the floating diffusion FD1. As shown in FIG. 3 , for example, one readout electrode 11A is provided for each pixel unit 1a consisting of four unit pixels P arranged in two rows and two columns. The readout electrode 11A is connected to the floating diffusion FD1 via, for example, an upper second contact 27A, a pad portion 26A, an upper first contact 25, a pad portion 24, a through electrode 34, a connection portion 41A, and a lower second contact 46.

[0025] The storage electrode 11B stores, for example, electrons as signal charges among the charge carriers generated in the photoelectric conversion layer 15, and is provided for each unit pixel P. The storage electrode 11B is provided for each unit pixel P in an area directly facing the light-receiving surfaces of the photoelectric conversion regions 32B, 32R formed in the semiconductor substrate 30 and covering these light-receiving surfaces. The storage electrode 11B is preferably larger than the readout electrode 11A, allowing a larger number of charge carriers to be stored. As shown in FIG. 10 , a voltage application unit 48 is connected to the storage electrode 11B via wiring such as an upper third contact 27B and a pad unit 26B.

[0026] The lower electrode 11 further includes a shield electrode 11C. The shield electrode 11C corresponds to a specific example of a "pixel separation electrode" according to an embodiment of the present disclosure. The shield electrode 11C is intended to prevent capacitive coupling between adjacent pixel units 1a. The shield electrode 11C is provided, for example, between adjacent pixel units 1a, and a fixed potential is applied to the shield electrode 11C. The shield electrode 11C further extends between adjacent pixels in the row direction (Y-axis direction) and column direction (X-axis direction) of four unit pixels P arranged in two rows and two columns that constitute the pixel unit 1a, as shown in FIG. 3, for example.

[0027] The lower electrode 11 is made of, for example, a conductive film having optical transparency. The lower electrode 11 preferably has a work function of, for example, 4.0 eV or more and 5.5 eV or less. The constituent material of such a lower electrode 11 is, for example, InP doped with tin (Sn) as a dopant. ２ O ３ Indium tin oxide (ITO) is an example of the material. The ITO film may have high or low crystallinity (close to amorphous). In addition to the above, the material for the lower electrode 11 may also be tin oxide (SnO ２ )-based materials, for example, ATO with antimony (Sb) added as a dopant, and FTO with fluorine (F) added as a dopant may be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added thereto may also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO ４ The lower electrode 11 may be made of CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0028] When the lower electrode 11 does not need to be optically transparent (for example, when light is incident from the upper electrode 16 side and the photoelectric conversion regions 32R and 32B are not provided below the storage electrode 11B), a single metal or alloy having a small work function (for example, φ=3.5 eV to 4.5 eV) can be used. Specific examples include alkali metals (for example, lithium (Li), sodium (Na), and potassium (K)) and their fluorides or oxides, and alkaline earth metals (for example, magnesium (Mg) and calcium (Ca)) and their fluorides or oxides. Other examples include rare earth metals such as aluminum (Al), Al—Si—Cu alloys, zinc (Zn), tin (Sn), thallium (Tl), Na—K alloys, Al—Li alloys, Mg—Ag alloys, In, and ytterbium (Yb), or alloys thereof.

[0029] Examples of materials that can be used to form the lower electrode 11 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), and molybdenum (Mo), alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials that can be used to form the lower electrode 11 include organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT / PSS). Alternatively, the above materials can be mixed with a binder (polymer) to form a paste or ink, which can then be cured and used as an electrode.

[0030] The lower electrode 11 can be formed as a single layer or a laminated film made of the above materials. The film thickness of the lower electrode 11 in the lamination direction (hereinafter simply referred to as thickness) is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0031] The insulating layer 12 serves to electrically separate the storage electrode 11B from the oxide semiconductor layer 13. The insulating layer 12 is provided, for example, on the interlayer insulating layer 23 so as to cover the lower electrode 11. An opening 12H is provided in the insulating layer 12 above the readout electrode 11A of the lower electrode 11, and the readout electrode 11A and the oxide semiconductor layer 13 are electrically connected via this opening 12H. The insulating layer 12 is made of, for example, silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ The insulating layer 12 is made of a single layer film made of one of silicon oxynitride (SiON) and silicon oxynitride (SiON), or a laminated film made of two or more of these materials. The thickness of the insulating layer 12 is, for example, 20 nm to 500 nm.

[0032] The oxide semiconductor layer 13 is for accumulating charge carriers generated in the photoelectric conversion layer 15. The oxide semiconductor layer 13 can be formed using an oxide semiconductor containing at least one element selected from the group consisting of indium (In), gallium (Ga), zinc (Zn), aluminum (Al), and tin (Sn). In this embodiment, electrons among the charge carriers generated in the photoelectric conversion layer 15 are used as signal charges. For this reason, the oxide semiconductor layer 13 can be formed using an n-type oxide semiconductor material. Specifically, the oxide semiconductor layer 13 can be formed using IGZO (In—Ga—Zn—O-based oxide semiconductor), gallium oxide (Ga ２ O ３ ), ZTO (Zn—Sn—O-based oxide semiconductor), IZO (In—Zn—O-based oxide semiconductor), ITO, indium gallium aluminum oxide (InGaAlO), and indium gallium silicon oxide (InGaSiO). The thickness of the oxide semiconductor layer 13 is, for example, 10 nm to 300 nm.

[0033] The protective layer 14 prevents oxygen from being released from the oxide semiconductor layer 13 and prevents defects from occurring on the surface of the oxide semiconductor layer 13 and in its vicinity. As described above, the protective layer 14 has an opening X1 above the storage electrode 11B, which makes the protective layer 14 thinner than other regions. The opening X1 has, for example, an area equal to or greater than half the area of ​​the storage electrode 11B in a plan view. In other words, the protective layer 14 has an opening X1 and a non-opening X2 in the XY plane. The opening X1 is formed above the storage electrode 11B and has an area equal to or greater than half the area of ​​the storage electrode 11B, as shown in FIG. 3 . The thickness of the protective layer 14 in the non-opening X2 is, for example, 1 nm or more and 100 nm or less. The thickness of the protective layer 14 in the opening X1 is thinner than the thickness of the protective layer 14 in the non-opening X2, for example, 5 nm or less.

[0034] The protective layer 14 can be formed using, for example, an oxide or nitride containing at least one of silicon (Si), germanium (Ge), aluminum (Al), hafnium (Hf), lanthanum (La), strontium (Sr), zirconium (Zr), vanadium (V), tantalum (Ta), titanium (Ti), yttrium (Y), magnesium (Mg), carbon (C), tin (Sn), erbium (Er), ytterbium (Yb), and gadolinium (Gd).

[0035] Here, the vacuum level is defined as zero, and the energy is defined as being greater (deeper) as the energy is further from the vacuum level, and smaller (shallower) as the energy is closer to the vacuum level. In the protective layer 14 formed using an inorganic oxide or inorganic nitride as described above, when the energy level of the conduction band minimum of the protective layer 14 is Ecn, the energy level of the lowest unoccupied molecular orbital of the photoelectric conversion layer 15 is Eco, and the energy level of the conduction band minimum of the oxide semiconductor layer 13 is Ecm, the relationships Ecm > Eco and Ecm > Ecn are satisfied. In other words, the protective layer 14 serves as a potential barrier when charge carriers (electrons) generated in the photoelectric conversion layer 15 by photoelectric conversion are transported to the oxide semiconductor layer 13. Therefore, it is desirable for the protective layer 14 to be thin so as not to impede the transport of electrons. However, a thin protective layer 14 presents a problem in that it is not possible to sufficiently suppress the formation of defects on the surface of the oxide semiconductor layer 13 and in its vicinity.

[0036] 5 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, protective layer 14, photoelectric conversion layer 15, and upper electrode 16 at an opening X1 corresponding to line A-A' in FIG. 4. FIG. 6 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, protective layer 14, photoelectric conversion layer 15, and upper electrode 16 at a non-opening X2 corresponding to line B-B' in FIG. 4. In this embodiment, an opening X1 is formed in the protective layer 14 above the storage electrode 11B, where charge carriers (electrons) generated in the photoelectric conversion layer 15 are accumulated. Therefore, the width of the potential barrier formed by the protective layer 14 at the opening X1 is narrower than the width of the potential barrier formed by the protective layer 14 at the non-opening X2, enabling transport of charge carriers (electrons) by the tunnel effect. Furthermore, since the transport efficiency of charge carriers (electrons) is ensured in the opening X1, the thickness of the protective layer 14 can be ensured in the non-opening X2 to sufficiently suppress the formation of defects on the surface of the oxide semiconductor layer 13 and in its vicinity.

[0037] The protective layer 14 may be removed from the opening X1, as shown in FIG. 7 , for example. That is, the thickness of the protective layer 14 at the opening X1 may be 0 nm. FIG. 8 shows an example of the energy levels of the storage electrode 11B, the insulating layer 12, the oxide semiconductor layer 13, the protective layer 14, the photoelectric conversion layer 15, and the upper electrode 16 at the opening X1 corresponding to the line A-A' shown in FIG. 7. At the opening X1 from which the protective layer 14 has been completely removed, the potential barrier caused by the protective layer 14 disappears, as shown in FIG. 8 , and therefore, charge carriers (electrons) can be transported without the tunneling effect.

[0038] 4, for example, the protective layer 14 preferably extends to cover the side surfaces of the oxide semiconductor layer 13 in the vicinity of the peripheral portion 100B. This prevents oxygen from being released from the side surfaces of the oxide semiconductor layer 13, and prevents defects from occurring on the side surfaces of the oxide semiconductor layer 13 and in their vicinity. Note that the side surfaces of the photoelectric conversion layer 15 may be formed outside the oxide semiconductor layer 13 so as to further cover the protective layer 14 covering the side surfaces of the oxide semiconductor layer 13, as shown in FIG. 4, for example, or may be formed inside the side surfaces of the oxide semiconductor layer 13, for example.

[0039] The photoelectric conversion layer 15 converts light energy into electrical energy. The photoelectric conversion layer 15 is configured, for example, to contain two or more organic materials (p-type semiconductor materials or n-type semiconductor materials) that function as p-type or n-type semiconductors, respectively. The photoelectric conversion layer 15 has a junction surface (p / n junction surface) between a p-type semiconductor material and an n-type semiconductor material within the layer. The p-type semiconductor functions relatively as an electron donor, and the n-type semiconductor functions relatively as an electron acceptor. The photoelectric conversion layer 15 provides a site where excitons generated upon light absorption separate into electrons and holes. Specifically, the excitons separate into electrons and holes at the interface (p / n junction surface) between the electron donor and electron acceptor.

[0040] In addition to the p-type and n-type semiconductor materials, the photoelectric conversion layer 15 may also contain an organic material, a so-called dye material, that photoelectrically converts light in a predetermined wavelength range while transmitting light in other wavelength ranges. When the photoelectric conversion layer 15 is formed using three types of organic materials, i.e., a p-type semiconductor material, an n-type semiconductor material, and a dye material, the p-type and n-type semiconductor materials are preferably materials that are optically transparent in the visible range (e.g., 450 nm to 800 nm). The thickness of the photoelectric conversion layer 15 is, for example, 50 nm to 500 nm.

[0041] Examples of organic materials constituting the photoelectric conversion layer 15 include quinacridone derivatives, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluoranthene derivatives. The photoelectric conversion layer 15 is formed by combining two or more of the above organic materials. The above organic materials function as p-type or n-type semiconductors depending on the combination.

[0042] There are no particular limitations on the organic material that constitutes the photoelectric conversion layer 15. Examples of organic materials that can be used to constitute the photoelectric conversion layer 15 include polymers of phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, and derivatives thereof. Examples of organic materials constituting the photoelectric conversion layer 15 include metal complex dyes, cyanine dyes, merocyanine dyes, phenylxanthene dyes, triphenylmethane dyes, rhodacyanine dyes, xanthene dyes, macrocyclic azaannulene dyes, azulene dyes, naphthoquinone dyes, anthraquinone dyes, condensed polycyclic aromatic compounds such as pyrene, chain compounds in which aromatic rings or heterocyclic compounds are condensed, quinoline having a squarylium group and a croconite methine group as a bonding chain, benzothiazole, benzoxazole, and other nitrogen-containing heterocycles, or cyanine-like dyes bonded by a squarylium group and a croconite methine group. Metal complex dyes include dithiol metal complex dyes, metal phthalocyanine dyes, metal porphyrin dyes, and ruthenium complex dyes. Among these, ruthenium complex dyes are particularly preferred, but are not limited to these. However, the photoelectric conversion layer 15 may be made of quantum dots or the like in addition to the organic material.

[0043] The upper electrode 16 is made of, for example, a light-transmitting conductive film, similar to the lower electrode 11. The upper electrode 16 is made of, for example, InP doped with Sn. ２ O ３The crystallinity of the ITO film may be high or low (close to amorphous). In addition to the above, the upper electrode 16 may also be made of SnO ２ Examples of the ZnO-based material include ATO with Sb added as a dopant and FTO with fluorine added as a dopant. ZnO or a zinc oxide-based material with a dopant added may also be used. Examples of the ZnO-based material include AZO with Al added as a dopant, GZO with Ga added, boron zinc oxide with B added, and IZO with In added. IGZO (In-GaZnO4) may also be used with indium and gallium added as dopants. Examples of the material for the upper electrode 16 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0044] Furthermore, if optical transparency is not required for the upper electrode 16, a single metal or alloy having a large work function (for example, φ=4.5 eV to 5.5 eV) can be used. Specific examples include Au, Ag, Cr, Ni, Pd, Pt, Fe, iridium (Ir), germanium (Ge), osmium (Os), rhenium (Re), tellurium (Te), and alloys thereof.

[0045] Furthermore, examples of materials constituting the upper electrode 16 include metals such as Pt, Au, Pd, Cr, Ni, Al, Ag, Ta, W, Cu, Ti, In, Sn, Fe, Co, and Mo, or alloys containing these metal elements, or conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, graphene, and other conductive substances. Other examples of materials constituting the upper electrode 16 include organic materials (conductive polymers) such as PEDOT / PSS. Furthermore, the above materials may be mixed with a binder (polymer) to form a paste or ink, which may then be hardened and used as an electrode.

[0046] The upper electrode 16 can be formed as a single layer or a laminated film made of the above materials. The thickness of the upper electrode 16 is, for example, 20 nm to 200 nm, preferably 30 nm to 150 nm.

[0047] The photoelectric conversion unit 10 may include other layers between the lower electrode 11 and the photoelectric conversion layer 15 and between the photoelectric conversion layer 15 and the upper electrode 16. For example, a hole blocking layer may be provided between the lower electrode 11 and the photoelectric conversion layer 15. The hole blocking layer prevents holes from moving from the lower electrode 11 to the photoelectric conversion layer 15 and efficiently transports electrons, among charge carriers generated in the photoelectric conversion layer 15, to the lower electrode 11. An electron blocking layer or a work function adjustment layer may be provided between the photoelectric conversion layer 15 and the upper electrode 16. The electron blocking layer prevents electrons from moving from the upper electrode 16 to the photoelectric conversion layer 15 and efficiently transports holes, among charge carriers generated in the photoelectric conversion layer 15, to the upper electrode 16. The work function adjustment layer has an electron affinity or work function greater than the work function of the upper electrode 16 and improves the electrical connection between the photoelectric conversion layer 15 and the upper electrode 16.

[0048] 1 and 3 show an example in which the insulating layer 12, the oxide semiconductor layer 13, the photoelectric conversion layer 15, and the upper electrode 16 are formed separately for each unit pixel P, but the oxide semiconductor layer 13, the photoelectric conversion layer 15, and the upper electrode 16 may be formed continuously for multiple unit pixels P, for example.

[0049] The fixed charge layer 21 serves to reduce the interface state with the semiconductor substrate 30 and to suppress the generation of dark current from the interface with the semiconductor substrate 30. The fixed charge layer 21 may be a film having positive fixed charges or a film having negative fixed charges. The fixed charge layer 21 is preferably formed using a semiconductor material or a conductive material having a wider band gap than the semiconductor substrate 30. This makes it possible to suppress the generation of dark current at the interface with the semiconductor substrate 30. The fixed charge layer 21 may be formed using, for example, hafnium oxide (HfO ｘ ), aluminum oxide (AlO ｘ ), zirconium oxide (ZrO ｘ ), tantalum oxide (TaO ｘ ), titanium oxide (TiO ｘ ), lanthanum oxide (LaO ｘ ), praseodymium oxide (PrO ｘ ), cerium oxide (CeO ｘ ), neodymium oxide (NdO ｘ ), promethium oxide (PmO ｘ ), samarium oxide (SmO ｘ ), europium oxide (EuO ｘ ), gadolinium oxide (GdO ｘ ), terbium oxide (TbO ｘ ), dysprosium oxide (DyO ｘ ), holmium oxide (HoO ｘ ), thulium oxide (TmO ｘ ), ytterbium oxide (YbO ｘ ), lutetium oxide (LuO ｘ ), yttrium oxide (YO ｘ), hafnium nitride (HfN ｘ ), aluminum nitride (AlN ｘ ), hafnium oxynitride (HfO ｘ N ｙ ) and aluminum oxynitride (AlO ｘ N ｙ ) etc.

[0050] The dielectric layer 22 is intended to prevent light reflection caused by the difference in refractive index between the semiconductor substrate 30 and the interlayer insulating layer 23. The dielectric layer 22 is preferably formed using a material having a refractive index between the refractive index of the semiconductor substrate 30 and the refractive index of the interlayer insulating layer 23. Examples of materials that can be used to form the dielectric layer 22 include silicon oxide, TEOS, silicon nitride, and silicon oxynitride (SiON).

[0051] The interlayer insulating layer 23 is configured, for example, as a single layer film made of one of silicon oxide, silicon nitride, silicon oxynitride, etc., or as a laminated film made of two or more of these. The interlayer insulating layer 23 is provided with pad portions 24, 26A, 26B, an upper first contact 25, an upper second contact 27A, an upper third contact 27B, etc.

[0052] The photoelectric conversion regions 32B and 32R are configured by, for example, PIN (Positive Intrinsic Negative) type photodiodes, and each has a pn junction in a predetermined region of the semiconductor substrate 30. The photoelectric conversion regions 32B and 32R are capable of splitting light in the vertical direction by utilizing the fact that the wavelength of light absorbed varies depending on the depth of incidence of the light in the silicon substrate.

[0053] The photoelectric conversion region 32B selectively detects, for example, blue light and accumulates signal charges corresponding to blue, and is located at a depth that allows efficient photoelectric conversion of blue light. The photoelectric conversion region 32R selectively detects, for example, red light and accumulates signal charges corresponding to red, and is located at a depth that allows efficient photoelectric conversion of red light. Note that blue (B) corresponds to, for example, a wavelength range of 400 nm or more and less than 495 nm, and red (R) corresponds to, for example, a wavelength range of 620 nm or more and less than 750 nm. Each of the photoelectric conversion regions 32B and 32R may be capable of detecting light in some or all of the wavelength ranges.

[0054] 3, the photoelectric conversion region 32B and the photoelectric conversion region 32R each have, for example, a p+ region that serves as a hole accumulation layer and an n region that serves as an electron accumulation layer (having a p-n-p stacked structure). The n region of the photoelectric conversion region 32B is connected to the transfer transistor Tr2. The p+ region of the photoelectric conversion region 32B bends along the transfer transistor Tr2 and is connected to the p+ region of the photoelectric conversion region 32R.

[0055] The gate insulating layer 33 is configured, for example, as a single layer film made of one of silicon oxide, silicon nitride, silicon oxynitride, etc., or as a laminated film made of two or more of these materials.

[0056] The through electrode 34 is provided between the first surface 30A and the second surface 30B of the semiconductor substrate 30, and functions as a connector between the photoelectric conversion unit 10 and the gate Gamp of the amplifier transistor AMP and the floating diffusion FD1, and also serves as a transmission path for charge carriers generated in the photoelectric conversion unit 10. A reset gate Grst of the reset transistor RST is disposed next to the floating diffusion FD1 (one of the source / drain regions 36B of the reset transistor RST). This makes it possible for the reset transistor RST to reset the charge carriers accumulated in the floating diffusion FD1.

[0057] The upper end of the through electrode 34 is connected to the read electrode 11A via, for example, a pad portion 24, an upper first contact 25, a pad portion 26A, and an upper second contact 27A provided in the interlayer insulating layer 23. The lower end of the through electrode 34 is connected to a connection portion 41A in the wiring layer 41, and the connection portion 41A and the gate Gamp of the amplifier transistor AMP are connected via a lower first contact 45. The connection portion 41A and the floating diffusion FD1 (region 36B) are connected via, for example, a lower second contact 46.

[0058] The pad portions 24, 26A, 26B, the upper first contact 25, the upper second contact 27A, the upper third contact 27B, the lower first contact 45, the lower second contact 46, and the wiring 53 can be formed using, for example, a silicon material doped with impurities such as PDAS (Phosphorus Doped Amorphous Silicon), or a metal material such as aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), hafnium (Hf), and tantalum (Ta).

[0059] The protective layer 51 protects the upper surface of the upper electrode 16 and also flattens the surface on the light incident surface S1 side of the photoelectric conversion body 10. The protective layer 51 is made of a light-transmitting material, such as silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ ), silicon oxynitride (SiON) and aluminum oxide (AlO ｘ The protective layer 51 has a thickness of, for example, 100 nm to 30,000 nm.

[0060] The on-chip lens 52 is made of a light-transmitting material, such as silicon oxide, silicon nitride, silicon oxynitride, etc. An anti-reflection film may be provided on the surface of the on-chip lens 52.

[0061] Fig. 9 is an equivalent circuit diagram of the photodetector element 1 shown in Fig. 1. Fig. 10 is a schematic diagram showing the arrangement of the lower electrode 11 and transistors constituting the control section of the photodetector element 1 shown in Fig. 1.

[0062] The reset transistor RST (reset transistor TR1rst) is used to reset charge carriers transferred from the photoelectric conversion unit 10 to the floating diffusion FD1, and is configured, for example, by a MOS transistor. Specifically, the reset transistor TR1rst is configured by a reset gate Grst, a channel formation region 36A, and source / drain regions 36B and 36C. The reset gate Grst is connected to a reset line RST1, and one source / drain region 36B of the reset transistor TR1rst also serves as the floating diffusion FD1. The other source / drain region 36C constituting the reset transistor TR1rst is connected to a power supply line VDD.

[0063] The amplifier transistor AMP (amplifier transistor TR1amp) is a modulation element that modulates the amount of charge generated in the photoelectric conversion unit 10 into a voltage, and is configured, for example, by a MOS transistor. Specifically, the amplifier transistor AMP is configured with a gate Gamp, a channel formation region 35A, and source / drain regions 35B and 35C. The gate Gamp is connected to the readout electrode 11A and one source / drain region 36B (floating diffusion FD1) of the reset transistor TR1rst via a lower first contact 45, a connection portion 41A, a lower second contact 46, a through-electrode 34, etc. Furthermore, one source / drain region 35B shares an area with the other source / drain region 36C that constitutes the reset transistor TR1rst and is connected to the power supply line VDD.

[0064] The select transistor SEL (select transistor TR1sel) is composed of a gate Gsel, a channel formation region 34A, and source / drain regions 34B and 34C. The gate Gsel is connected to a select line SEL1. One source / drain region 34B shares an area with the other source / drain region 35C that constitutes the amplifier transistor AMP, and the other source / drain region 34C is connected to a signal line (data output line) VSL1.

[0065] The transfer transistor TR2 (transfer transistor TR2trs) transfers signal charges corresponding to blue generated and accumulated in the photoelectric conversion region 32B to the floating diffusion FD2. Because the photoelectric conversion region 32B is formed deep below the second surface 30B of the semiconductor substrate 30, the transfer transistor TR2trs in the photoelectric conversion region 32B is preferably configured as a vertical transistor. The transfer transistor TR2trs is connected to a transfer gate line TG2. A floating diffusion FD2 is provided in the region 37C near the gate Gtrs2 of the transfer transistor TR2trs. Charge carriers accumulated in the photoelectric conversion region 32B are read out to the floating diffusion FD2 via a transfer channel formed along the gate Gtrs2.

[0066] The transfer transistor TR3 (transfer transistor TR3trs) transfers the signal charges corresponding to red that are generated and accumulated in the photoelectric conversion region 32R to the floating diffusion FD3, and is configured, for example, by a MOS transistor. The transfer transistor TR3trs is connected to a transfer gate line TG3. A floating diffusion FD3 is provided in the region 38C near the gate Gtrs3 of the transfer transistor TR3trs. The charge carriers accumulated in the photoelectric conversion region 32R are read out to the floating diffusion FD3 via a transfer channel formed along the gate Gtrs3.

[0067] Further provided on the second surface 30B side of the semiconductor substrate 30 are a reset transistor TR2rst, an amplifier transistor TR2amp, and a selection transistor TR2sel that constitute a control section of the photoelectric conversion region 32B. Further provided are a reset transistor TR3rst, an amplifier transistor TR3amp, and a selection transistor TR3sel that constitute a control section of the photoelectric conversion region 32R.

[0068] The reset transistor TR2rst is composed of a gate, a channel forming region, and source / drain regions. The gate of the reset transistor TR2rst is connected to a reset line RST2, and one of the source / drain regions of the reset transistor TR2rst is connected to a power supply line VDD. The other source / drain region of the reset transistor TR2rst also serves as a floating diffusion FD2.

[0069] The amplifier transistor TR2amp is composed of a gate, a channel forming region, and source / drain regions. The gate is connected to the other source / drain region (floating diffusion FD2) of the reset transistor TR2rst. One of the source / drain regions constituting the amplifier transistor TR2amp shares the same region with one of the source / drain regions constituting the reset transistor TR2rst and is connected to the power supply line VDD.

[0070] The selection transistor TR2sel is composed of a gate, a channel formation region, and source / drain regions. The gate is connected to a selection line SEL2. One of the source / drain regions constituting the selection transistor TR2sel is shared with the other source / drain region constituting the amplifier transistor TR2amp. The other source / drain region constituting the selection transistor TR2sel is connected to a signal line (data output line) VSL2.

[0071] The reset transistor TR3rst is composed of a gate, a channel forming region, and source / drain regions. The gate of the reset transistor TR3rst is connected to a reset line RST3, and one of the source / drain regions constituting the reset transistor TR3rst is connected to a power supply line VDD. The other source / drain region constituting the reset transistor TR3rst also serves as a floating diffusion FD3.

[0072] The amplifier transistor TR3amp is composed of a gate, a channel forming region, and source / drain regions. The gate is connected to the other source / drain region (floating diffusion FD3) constituting the reset transistor TR3rst. One of the source / drain regions constituting the amplifier transistor TR3amp shares the same region with one of the source / drain regions constituting the reset transistor TR3rst and is connected to the power supply line VDD.

[0073] The selection transistor TR3sel is composed of a gate, a channel formation region, and source / drain regions. The gate is connected to a selection line SEL3. One of the source / drain regions constituting the selection transistor TR3sel shares the same region with the other of the source / drain regions constituting the amplifier transistor TR3amp. The other of the source / drain regions constituting the selection transistor TR3sel is connected to a signal line (data output line) VSL3.

[0074] The reset lines RST1, RST2, and RST3, the selection lines SEL1, SEL2, and SEL3, and the transfer gate lines TG2 and TG3 are connected to vertical drive circuits that constitute the drive circuit, and the signal lines (data output lines) VSL1, VSL2, and VSL3 are connected to a column signal processing circuit 112 that constitutes the drive circuit.

[0075] In the photodetector element 1, an optical black (OPB) layer 54 is formed above the photoelectric conversion unit 10 in the vicinity of the peripheral portion 100B. For example, as shown in FIG. 4 , the OPB layer 58 covers the side surface of the photoelectric conversion unit 20 and extends to the peripheral portion 100B.

[0076] [Method for Manufacturing Photodetector] The photodetector 1 of this embodiment can be manufactured, for example, as follows.

[0077] 11 to 16 show the process sequence of the manufacturing method of the photodetector element 1. First, as shown in Fig. 11, for example, a p-well 31 is formed in a semiconductor substrate 30, and for example, n-type photoelectric conversion regions 32B and 32R are formed in this p-well 31. A p+ region is formed near the first surface 30A of the semiconductor substrate 30.

[0078] 11 , n+ regions that will become floating diffusions FD1 to FD3 are formed on the second surface 30B of the semiconductor substrate 30, followed by the formation of a gate insulating layer 33 and a gate wiring layer 47 including the gates of the transfer transistor Tr2, the transfer transistor Tr3, the select transistor SEL, the amplifier transistor AMP, and the reset transistor RST. This results in the formation of the transfer transistor Tr2, the transfer transistor Tr3, the select transistor SEL, the amplifier transistor AMP, and the reset transistor RST. Furthermore, a multilayer wiring layer 40 is formed on the second surface 30B of the semiconductor substrate 30, which includes wiring layers 41 to 43, each including a lower first contact 45, a lower second contact 46, and a connection portion 41A, and an insulating layer 44.

[0079] The base of the semiconductor substrate 30 is, for example, an SOI (Silicon on Insulator) substrate in which the semiconductor substrate 30, a buried oxide film (not shown), and a holding substrate (not shown) are stacked. Although not shown in FIG. 11 , the buried oxide film and the holding substrate are bonded to the first surface 30A of the semiconductor substrate 30. After the ion implantation, an annealing process is performed.

[0080] Next, a support substrate (not shown) or another semiconductor substrate is bonded to the multilayer wiring layer 40 provided on the second surface 30B side of the semiconductor substrate 30, and the semiconductor substrate 30 is then turned upside down. Subsequently, the semiconductor substrate 30 is separated from the buried oxide film of the SOI substrate and the support substrate, exposing the first surface 30A of the semiconductor substrate 30. The above steps can be performed using techniques used in ordinary CMOS processes, such as ion implantation and CVD (Chemical Vapor Deposition).

[0081] 12, the semiconductor substrate 30 is processed from the first surface 30A side by, for example, dry etching to form, for example, an annular opening 34H. As shown in FIG. 12, the depth of the opening 34H penetrates from the first surface 30A to the second surface 30B of the semiconductor substrate 30 and reaches, for example, the connection portion 41A.

[0082] Next, for example, a negative fixed charge layer 21 and a dielectric layer 22 are formed in this order on the first surface 30A of the semiconductor substrate 30 and the side surface of the opening 34H. The fixed charge layer 21 is formed of, for example, HfO ｘ The dielectric layer 22 can be formed by depositing a SiO film using, for example, a plasma CVD method. ｘ Next, a pad portion 24 is formed at a predetermined position on the dielectric layer 22. The pad portion 24 is made of a barrier metal, for example, a laminated film of titanium and titanium nitride (Ti / TiN film), and a W film. Thereafter, an interlayer insulating layer 23 is formed on the dielectric layer 22 and the pad portion 24, and the surface of the interlayer insulating layer 23 is planarized using a chemical mechanical polishing (CMP) method.

[0083] 13, an opening 23H is formed on the pad portion 24, and then a conductive material such as Al is filled into this opening 23H to form the upper first contact 25. Next, as shown in FIG. 13, pad portions 26A and 26B are formed in the same manner as the pad portion 24, and then the interlayer insulating layer 23 and the upper second contact 27A and upper third contact 27B are formed in this order.

[0084] 14, a conductive film 11X is formed on the interlayer insulating layer 23 by, for example, sputtering, and then patterned by photolithography. Specifically, a photoresist PR is formed at a predetermined position on the conductive film 11X, and then the conductive film 11X is processed by dry etching or wet etching. The photoresist PR is then removed, thereby forming the read electrode 11A and the storage electrode 11B as shown in FIG.

[0085] Next, as shown in FIG. 16 , the insulating layer 12, the oxide semiconductor layer 13, the protective layer 14, the photoelectric conversion layer 15, and the upper electrode 16 are sequentially formed. The insulating layer 12 is formed by depositing a silicon oxide film using, for example, the ALD method, and then planarizing the surface of the insulating layer 12 using the CMP method. Then, an opening 12H is formed on the readout electrode 11A using, for example, wet etching. The oxide semiconductor layer 13 can be formed using, for example, the sputtering method. The protective layer 14 can be formed using, for example, the ALD method. The opening X1 can be formed, for example, by photolithography. Specifically, a photoresist PR is formed at a predetermined position on the protective layer 14, and then the protective layer 14 is processed using dry etching or wet etching. The photoresist PR is then removed, thereby forming the opening X1 above the storage electrode 11B, as shown in FIG. 16 . The photoelectric conversion layer 15 is formed using, for example, the vacuum deposition method. The upper electrode 16 is formed by, for example, sputtering, in the same manner as the lower electrode 11. Thereafter, a protective layer 51 is formed so as to cover the upper electrode 16, and then an on-chip lens 52 is disposed on the protective layer 51. In this manner, the photodetector element 1 shown in FIG. 1 is completed.

[0086] Conductive films such as the photoelectric conversion layer 15, the lower electrode 11, and the upper electrode 16 can be formed using a dry film formation method or a wet film formation method. Examples of dry film formation methods include vacuum deposition using resistance heating or high-frequency heating, electron beam (EB) deposition, various sputtering methods (magnetron sputtering, RF-DC coupled bias sputtering, ECR sputtering, facing target sputtering, and high-frequency sputtering), ion plating, laser ablation, molecular beam epitaxy, and laser transfer. Other examples of dry film formation methods include chemical vapor deposition methods such as plasma CVD, thermal CVD, MOCVD, and photo-CVD. Examples of wet film formation methods include spin coating, inkjet printing, spray coating, stamping, microcontact printing, flexographic printing, offset printing, gravure printing, and dipping.

[0087] For patterning, in addition to photolithography, chemical etching such as shadow mask and laser transfer, physical etching using ultraviolet light or laser, etc. can be used. As for planarization techniques, in addition to CMP, laser planarization, reflow, etc. can be used.

[0088] [Signal Acquisition Operation of Photodetection Element] In the photodetection element 1, when light is incident on the photoelectric conversion unit 10 via the on-chip lens 52, the light passes through the photoelectric conversion unit 10 and the photoelectric conversion regions 32B and 32R in that order, and is photoelectrically converted into green, blue, and red light during the passage. The signal acquisition operation for each color will be described below.

[0089] (Acquisition of Green Signal by Photoelectric Conversion Unit 10) Of the light incident on the photodetector element 1, green light (G) is first selectively detected (absorbed) by the photoelectric conversion unit 10 and photoelectrically converted.

[0090] The photoelectric conversion unit 10 is connected to the gate Gamp of the amplifier transistor AMP and the floating diffusion FD1 via the through electrode 34. Therefore, electrons of the excitons generated in the photoelectric conversion unit 10 are extracted from the lower electrode 11 side, transferred to the second surface 30B side of the semiconductor substrate 30 via the through electrode 34, and accumulated in the floating diffusion FD1. At the same time, the amount of charge generated in the photoelectric conversion unit 10 is modulated into a voltage by the amplifier transistor AMP.

[0091] In addition, a reset gate Grst of the reset transistor RST is disposed next to the floating diffusion FD1, so that the charge carriers accumulated in the floating diffusion FD1 are reset by the reset transistor RST.

[0092] Since the photoelectric conversion unit 10 is connected not only to the amplifier transistor AMP but also to the floating diffusion FD1 via the through electrode 34, the charge carriers accumulated in the floating diffusion FD1 can be easily reset by the reset transistor RST.

[0093] On the other hand, if the through electrode 34 and the floating diffusion FD1 are not connected, it becomes difficult to reset the charge carriers accumulated in the floating diffusion FD1, and a large voltage must be applied to extract them to the upper electrode 16. This may damage the photoelectric conversion layer 15. Furthermore, a structure that enables resetting in a short time increases dark noise, which is a trade-off, making this structure difficult to implement.

[0094] 17 shows an example of operation of the photodetector element 1. (A) shows the potential at the storage electrode 11B, (B) shows the potential at the floating diffusion FD1 (readout electrode 11A), and (C) shows the potential at the gate (Gsel) of the reset transistor TR1rst. In the photodetector element 1, voltages are applied to the readout electrode 11A and the storage electrode 11B individually.

[0095] In the photodetector element 1, during the accumulation period, a potential V1 is applied to the readout electrode 11A from the drive circuit, and a potential V2 is applied to the storage electrode 11B. Here, the relationship between potentials V1 and V2 is set to V2 > V1. As a result, charge carriers (signal charges; electrons) generated by photoelectric conversion are attracted to the storage electrode 11B and accumulated in the region of the oxide semiconductor layer 13 facing the storage electrode 11B (accumulation period). Incidentally, the potential of the region of the oxide semiconductor layer 13 facing the storage electrode 11B becomes more negative as the photoelectric conversion time elapses. Note that holes are sent from the upper electrode 16 to the drive circuit.

[0096] In the photodetector element 1, a reset operation is performed in the latter half of the accumulation period. Specifically, at timing t1, the scanning unit changes the voltage of the reset signal RST from low to high. As a result, in the unit pixel P, the reset transistor TR1rst is turned on, and as a result, the voltage of the floating diffusion FD1 is set to the power supply voltage and the voltage of the floating diffusion FD1 is reset (reset period).

[0097] After the reset operation is completed, the charge carriers are read out. Specifically, at timing t2, the drive circuit applies a potential V3 to the readout electrode 11A and a potential V4 to the storage electrode 11B. Here, the potentials V3 and V4 are set to V3 > V4. As a result, the charge carriers stored in the region corresponding to the storage electrode 11B are read out from the readout electrode 11A to the floating diffusion FD1. That is, the charge carriers stored in the oxide semiconductor layer 13 are read out to the control unit (transfer period).

[0098] After the read operation is completed, the drive circuit again applies potential V1 to the read electrode 11A and potential V2 to the storage electrode 11B, causing charge carriers generated by photoelectric conversion to be attracted to the storage electrode 11B and stored in the region of the photoelectric conversion layer 15 facing the storage electrode 11B (storage period).

[0099] (Acquisition of Blue and Red Signals by Photoelectric Conversion Regions 32B and 32R) Next, of the light transmitted through the photoelectric conversion unit 10, blue light (B) is absorbed and photoelectrically converted in the photoelectric conversion region 32B, and red light (R) is absorbed and photoelectrically converted in the photoelectric conversion region 32R. In the photoelectric conversion region 32B, electrons corresponding to the incident blue light (B) are accumulated in the n-region of the photoelectric conversion region 32B, and the accumulated electrons are transferred to the floating diffusion FD2 by the transfer transistor Tr2. Similarly, in the photoelectric conversion region 32R, electrons corresponding to the incident red light (R) are accumulated in the n-region of the photoelectric conversion region 32R, and the accumulated electrons are transferred to the floating diffusion FD3 by the transfer transistor Tr3.

[0100] [Functions and Effects] In the photodetector element 1 of this embodiment, in the photoelectric conversion unit 10 in which the oxide semiconductor layer 13, the protective layer 14, and the photoelectric conversion layer 15 are stacked in this order from the lower electrode 11 side between the lower electrode 11 and the upper electrode 16, an opening X1 having a smaller film thickness than other regions (non-openings X2) is formed in the protective layer 14 above the storage electrode 11B that constitutes the lower electrode 11. This suppresses the formation of oxygen defects in the oxide semiconductor layer 13 without preventing the movement of charge carriers generated in the photoelectric conversion layer 15 by photoelectric conversion to the oxide semiconductor layer 13. This is described below.

[0101] In recent years, as pixel size has decreased in CCD image sensors and CMOS image sensors, the number of photons incident on each pixel has decreased, resulting in a decrease in sensitivity and a decrease in S / N. In addition, currently widely used image sensors have red, green, and blue pixels, each of which is fitted with a primary color filter, arranged in a Bayer pattern. However, in each color pixel, light other than the corresponding color light (e.g., green and blue light in the case of a red pixel) does not pass through the color filter and is not used for photoelectric conversion, resulting in a loss of sensitivity. Furthermore, the creation of color signals by interpolating between pixels creates the problem of false colors.

[0102] To solve these problems, an image sensor has been proposed in which three photoelectric conversion layers are stacked vertically to obtain three-color photoelectric conversion signals per pixel. As a structure in which three photoelectric conversion layers are stacked per pixel, for example, an image sensor has been proposed in which a photoelectric conversion unit that detects green light and generates a corresponding signal charge is provided above a silicon substrate, and blue and red light are detected by two PDs stacked within the silicon substrate. Other proposed structures include a back-illuminated structure in which a single organic photoelectric conversion film is provided above a silicon substrate and two inorganic photoelectric conversion units are provided within the silicon substrate, with the circuit formation surface formed on the opposite side from the light-receiving surface, and a structure in which an oxide semiconductor film and an insulating film for charge storage and transfer are provided directly below the photoelectric conversion film, and multiple electrodes (charge readout electrodes and charge storage electrodes) are used as lower electrodes.

[0103] In the former case, when an organic photoelectric conversion layer is formed in a back-illuminated configuration, no circuitry or wiring is formed between the inorganic photoelectric conversion unit and the organic photoelectric conversion unit, allowing the inorganic photoelectric conversion unit and the organic photoelectric conversion unit to be closer to each other within the same pixel. This reduces the F-number dependency of each color and suppresses variations in sensitivity between colors. In the latter case, the charge storage electrode is disposed opposite the photoelectric conversion layer via an insulating layer, allowing charge carriers generated by photoelectric conversion to be stored in the oxide semiconductor film. This allows the charge storage unit to be completely depleted and the charge to be erased at the start of exposure. As a result, it is possible to suppress phenomena such as increased kTC noise, deterioration of random noise, and deterioration of image quality.

[0104] However, as described above, in image sensors in which an insulating film and an oxide semiconductor film are stacked between multiple electrodes and a photoelectric conversion layer, defects caused by oxygen desorption from the oxide semiconductor layer have become a problem. Therefore, a structure has been proposed in which oxygen desorption from the oxide semiconductor layer is prevented by stacking an oxide film on the oxide semiconductor film, as described above. Defects in the oxide semiconductor film can be reduced by terminating the oxide semiconductor film with elements such as hydrogen, but the oxide film easily desorbs during processes after the oxide film formation. Furthermore, the conduction band energy and film thickness of the oxide film are limited to avoid impeding the transport of charge carriers from the photoelectric conversion layer. For example, as described above, an oxide film formed using an inorganic oxide generally has a shallower conduction band energy than the photoelectric conversion layer, which creates a potential barrier when transporting charge carriers generated in the photoelectric conversion layer to the oxide semiconductor film. Therefore, it is desirable to make the oxide film thin so as not to impede electron transport. However, thin oxide films cannot prevent oxygen desorption from the surface of the oxide semiconductor film, and therefore cannot adequately suppress the formation of defects at or near the surface of the oxide semiconductor film.

[0105] In contrast, in the present embodiment, as described above, in the photoelectric conversion unit 10 in which the oxide semiconductor layer 13, the protective layer 14, and the photoelectric conversion layer 15 are stacked in this order from the lower electrode 11 side between the lower electrode 11 and the upper electrode 16, an opening X1 is formed in the protective layer 14 above the storage electrode 11B that can store charge carriers generated by photoelectric conversion, the opening X1 having a smaller film thickness than other regions (non-openings X2). This makes it possible to transport charge carriers from the photoelectric conversion layer 15 to the oxide semiconductor layer 13 even if the film thickness of the protective layer 14 is increased. In addition, in the non-openings X2, the protective layer 14 can be made thick enough to sufficiently suppress the formation of defects on the surface of the oxide semiconductor layer 13 and in its vicinity.

[0106] As a result, the reliability of the photodetector element 1 according to this embodiment can be improved.

[0107] Furthermore, in the photodetector element 1 of this embodiment, the transport efficiency of charge carriers is ensured by forming the opening X1 in the protective layer 14 above the storage electrode 11B, as described above, which allows for greater freedom in selecting the material that constitutes the protective layer 14.

[0108] Next, the second and third embodiments, Modifications 1 to 32, and other Modifications 1 to 7 of the present disclosure, as well as application examples and applied examples, will be described. Note that components corresponding to the light detection element 1 of the first embodiment are given the same reference numerals and descriptions thereof will be omitted. Furthermore, the second to fourth embodiments, Modifications 1 to 33, and other Modifications 1 to 7 described below can be combined with each other as appropriate.

[0109] 18 is a schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 10A) of a photodetector according to a first modification of the present disclosure. FIG. 19 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of a photodetector device 100 including the photodetector shown in FIG. 18. Note that FIG. 18 illustrates a cross section corresponding to line II-II shown in FIG. 19. Similar to the photodetector device 1 of the first embodiment, the photodetector device including the photoelectric conversion unit 10A is a photodetector device such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel section 100A of the photodetector device 100 shown in FIG. 109, for example. In the pixel section 100A, as shown in FIG. 19, a pixel unit 1a consisting of four unit pixels P arranged in, for example, two rows and two columns serves as a repeating unit, and is repeatedly arranged in an array consisting of row and column directions.

[0110] In the first embodiment, an example in which the opening X1 is selectively provided only above the storage electrode 11B has been described, but this is not limiting. In the photoelectric conversion unit 10A of this modification, an opening X1 is provided above the readout electrode 11A in addition to above the storage electrode 11B. Except for this point, the photoelectric conversion unit 10A has substantially the same configuration as the photoelectric conversion unit 10 of the first embodiment.

[0111] In this way, in the photoelectric conversion unit 10A of this modification, the openings X1 are provided above the readout electrode 11A in addition to above the storage electrode 11B, so that it is possible to reduce charge carriers remaining above the non-openings X2. Therefore, in addition to the effect of the first embodiment, the photoelectric conversion unit 10A of this modification can reduce noise caused by charge carriers remaining above the non-openings X2.

[0112] (2-2. Modification 2) FIG. 20 is a schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 10B) of a photodetector according to Modification 2 of the present disclosure. FIG. 21 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of a photodetector device 100 including the photodetector shown in FIG. 20. Note that FIG. 20 illustrates a cross section corresponding to line III-III shown in FIG. 21. Similar to the photodetector device 1 of the first embodiment, the photodetector device including the photoelectric conversion unit 10B is a photodetector device such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel section 100A of the photodetector device 100 shown in FIG. 109, for example. In the pixel section 100A, as shown in FIG. 21, a pixel unit 1a consisting of four unit pixels P arranged in, for example, two rows and two columns serves as a repeating unit, and is repeatedly arranged in an array consisting of row and column directions.

[0113] The photoelectric conversion unit 10C of this modification further includes a transfer electrode 11D between the readout electrode 11A and the storage electrode 11B. Except for this point, the photoelectric conversion unit 10C has substantially the same configuration as the photoelectric conversion unit 10 of the first embodiment.

[0114] The transfer electrode 11D controls the energy potential of the oxide semiconductor layer 13 between the readout electrode 11A and the storage electrode 11B, and controls the flow of charge carriers stored in the oxide semiconductor layer 13 above the storage electrode 11B to the readout electrode 211. The transfer electrode 11D can be formed, for example, in the same layer as the readout electrode 11A, the storage electrode 11B, and the shield electrode 11C, and can be formed using the same material.

[0115] 21 shows an example in which the transfer electrodes 11D are individually provided between the readout electrode 11A disposed substantially in the center of the pixel unit 1a and the four storage electrodes 11B provided for each unit pixel P, but the present invention is not limited to this. The transfer electrodes 11D may be provided in each pixel unit 1a as a single electrode connected to surround the readout electrode 11A.

[0116] In this way, in the photoelectric conversion unit 10B of this modification, the transfer electrode 11D is provided between the readout electrode 11A and the storage electrode 11B, which improves the transfer speed of charge carriers stored above the storage electrode 11B to the readout electrode 211. Therefore, the photoelectric conversion unit 10B of this modification can reduce noise in addition to the effects of the first embodiment.

[0117] 22 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 10C) of a photodetector according to Modification 3 of the present disclosure. Similar to the photodetector 1 of the first embodiment, the photodetector including the photoelectric conversion unit 10C is a photodetector such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector 100 shown in FIG.

[0118] In the photoelectric conversion unit 10C of this modification, the side surface 14S of the opening X1 in the protective layer 14 is an inclined surface. Except for this point, the photoelectric conversion unit 10C has substantially the same configuration as the photoelectric conversion unit 10 of the first embodiment.

[0119] 22, the side surface 14S of the opening X1 is preferably inclined so that the area of ​​the top of the opening X1 is larger than the area of ​​the bottom of the opening X1. The smaller the inclination angle of the side surface 14S of the opening X1, the better, but it is preferable that the distance 11 in the XY plane between the top of the opening X1 and the nearby shield electrode 11C or transfer electrode 11D is 10 nm or more.

[0120] As described above, in the photoelectric conversion unit 10C of this modification, the side surface 14S of the opening X1 of the protective layer 14 is inclined, so that charge carriers accumulated above the storage electrode 11B can be smoothly transported to the readout electrode 211. Furthermore, in the photoelectric conversion unit 10C of this modification, charge carriers remaining above the non-opening X2 can be collected by applying an electric field in a direction oblique to the XY in-plane direction of the photoelectric conversion layer 15. Therefore, in addition to the effects of the first embodiment, the photoelectric conversion unit 10C of this modification can reduce noise. Furthermore, the photoelectric conversion unit 10C of this modification can improve sensitivity.

[0121] 23 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 10D) of a photodetector element according to Modification 4 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 10D is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0122] In the photoelectric conversion unit 10D of this modification, the protective layer 14 in the opening X1 is removed, and a recess structure is formed by recessing a portion of the oxide semiconductor layer 13 exposed at the bottom of the opening X1. Except for this point, the photoelectric conversion unit 10D has substantially the same configuration as the photoelectric conversion unit 10 of the first embodiment.

[0123] Defects caused by oxygen desorption from the oxide semiconductor layer 13 may also be formed by dry etching when processing the protective layer 14 .

[0124] In contrast, in the photoelectric conversion unit 10D of this modification, a portion of the oxide semiconductor layer 13 exposed at the bottom of the opening X1 and having defects formed therein is removed. The depth of the recess structure formed by removing this portion of the oxide semiconductor layer 13 is preferably equal to or less than half the thickness of the oxide semiconductor layer 13. The oxide semiconductor layer 13 having defects formed therein is removed by, for example, wet etching or dry etching. This makes it possible to reduce the number of defects contained in the oxide semiconductor layer 13. Therefore, the photoelectric conversion unit 10C of this modification can improve image quality in addition to the effects of the first embodiment described above.

[0125] (2-5. Modification 5) FIG. 24 is a schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 10E) of a photodetector according to Modification 5 of the present disclosure. FIG. 25 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of a photodetector device 100 including the photodetector element illustrated in FIG. 24. Note that FIG. 24 illustrates a cross section corresponding to line IV-IV illustrated in FIG. 25. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 10E is a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel section 100A of the photodetector device 100 illustrated in FIG. 109, for example. In the pixel section 100A, as illustrated in FIG. 25, a pixel unit 1a consisting of four unit pixels P arranged in, for example, two rows and two columns serves as a repeating unit, and is repeatedly arranged in an array consisting of row and column directions.

[0126] In the first embodiment, the opening X1 is provided inside the storage electrode 11B in plan view, but this is not limiting. In the photoelectric conversion unit 10E of this modification, the opening X1 is extended to the outside of the storage electrode 11B in plan view. Except for this, the photoelectric conversion unit 10E has substantially the same configuration as the photoelectric conversion unit 10 of the first embodiment and the photoelectric conversion unit 10B of the second modification.

[0127] From the viewpoint of reliability, it is preferable that non-openings X2 are formed above the shield electrode 11C and the transfer electrode 11D, and it is preferable that the distance l2 in the XY plane between the side surface of the opening X1 and the adjacent shield electrode 11C and transfer electrode 11D is 10 nm or more.

[0128] As described above, in the photoelectric conversion unit 10E of this modification, the opening X1 is provided to be larger than the storage electrode 11B in plan view. This makes it possible to reduce charge carriers remaining in the non-opening X2. Therefore, the photoelectric conversion unit 10E of this modification can reduce noise in addition to the effects of the first embodiment. Furthermore, the photoelectric conversion unit 10E of this modification can improve sensitivity.

[0129] (2-6. Modification 6) FIG. 26 is a schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 10F) of a photodetector according to Modification 6 of the present disclosure. FIG. 27 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of a photodetector device 100 including the photodetector shown in FIG. 26. Note that FIG. 26 illustrates a cross section corresponding to the V-V line shown in FIG. 27. Similar to the photodetector device 1 of the first embodiment, the photodetector device including the photoelectric conversion unit 10F is a photodetector device such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel section 100A of the photodetector device 100 shown in FIG. 109, for example. In the pixel section 100A, as shown in FIG. 27, a pixel unit 1a consisting of four unit pixels P arranged in, for example, two rows and two columns serves as a repeating unit, and is repeatedly arranged in an array consisting of row and column directions.

[0130] In the first modification, an example was shown in which an opening X1 was further provided inside the readout electrode 11A in plan view, but this is not limited to this. In the photoelectric conversion unit 10F of this modification, the opening X1 formed above the readout electrode 11A is extended to the outside of the readout electrode 11A in plan view. Except for this point, the photoelectric conversion unit 10F has substantially the same configuration as the photoelectric conversion unit 10 of the first embodiment and the photoelectric conversion units 10A and 10B of the first and second modifications.

[0131] From the viewpoint of reliability, it is preferable that a non-opening X2 is formed above the transfer electrode 11D, and it is preferable that the distance 13 in the XY plane between the side surface of the opening X1 and the adjacent transfer electrode 11D is 10 nm or more.

[0132] As described above, in the photoelectric conversion unit 10F of this modified example, an opening X1 larger than the readout electrode 11A is further provided above the readout electrode 11A in a plan view. This makes it possible to reduce charge carriers remaining above the non-opening X2. Therefore, the photoelectric conversion unit 10F of this modified example can reduce noise, similar to the above modified example 5. Furthermore, the photoelectric conversion unit 10F of this modified example can improve sensitivity.

[0133] 28 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 10G) of a photodetector element according to Modification 7 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 10G is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0134] The photoelectric conversion unit 10G of this modification further includes a tunnel layer 14A as a protective layer on the protective layer 14. Except for this point, the photoelectric conversion unit 10G has substantially the same configuration as the photoelectric conversion unit 10 of the first embodiment.

[0135] 29 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, protective layer 14, tunnel layer 14A, photoelectric conversion layer 15, and upper electrode 16 at an opening X1 corresponding to line A-A' in FIG. 28 . FIG. 30 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, protective layer 14, tunnel layer 14A, photoelectric conversion layer 15, and upper electrode 16 at a non-opening X2 corresponding to line B-B' in FIG. 28 . The tunnel layer 14A corresponds to a specific example of a "first layer" according to one embodiment of the present disclosure. Like the protective layer 14, the tunnel layer 14A prevents oxygen from being released from the oxide semiconductor layer 13 and prevents defects from occurring on the surface of the oxide semiconductor layer 13 and in its vicinity. For example, the tunnel layer 14A is provided over the entire surface of the pixel unit 100A. For example, when the energy level of the conduction band minimum of the tunnel layer 14A is Ecn', the energy level of the lowest unoccupied molecular orbital of the photoelectric conversion layer 15 is Eco, and the energy level of the conduction band minimum of the oxide semiconductor layer 13 is Ecm, the tunnel layer 14A satisfies Ecn'<Eco or Ecn'<Ecm and has a thickness of, for example, one atomic layer or more and 5 nm or less. For example, the tunnel layer 14A may be formed using the same material as the protective layer 14, or may be formed using a different material.

[0136] As described above, in the photoelectric conversion unit 10G of this modification, a tunnel layer 14A is further provided on the protective layer 14. This prevents oxygen from being released from the oxide semiconductor layer 13 even when the protective layer 14 in the opening X1 is removed, as shown in FIG. 7 . Therefore, the photoelectric conversion unit 10G of this modification can achieve the same effects as those of the first embodiment. (2-8. Modification 8) FIG. 31 schematically illustrates an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 10H) of a photodetector according to Modification 8 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 10H is a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector 100 shown in FIG. 109 .

[0137] The photoelectric conversion section 10H of this modification further includes a barrier-free layer 14B as a protective layer on the protective layer 14. Except for this point, the photoelectric conversion section 10H has substantially the same configuration as the photoelectric conversion section 10 of the first embodiment.

[0138] 32 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, protective layer 14, non-barrier layer 14B, photoelectric conversion layer 15, and upper electrode 16 at opening X1 corresponding to line A-A' in FIG. 31 . FIG. 33 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, protective layer 14, non-barrier layer 14B, photoelectric conversion layer 15, and upper electrode 16 at non-opening X2 corresponding to line B-B' in FIG. 31 . The non-barrier layer 14B corresponds to a specific example of a "first layer" according to one embodiment of the present disclosure. Like the protective layer 14, the non-barrier layer 14B prevents oxygen from being released from the oxide semiconductor layer 13 and prevents defects from occurring on the surface of the oxide semiconductor layer 13 and in its vicinity. For example, the non-barrier layer 14B is provided over the entire surface of the pixel unit 100A. The barrier-free layer 14B satisfies Eco<Ecn'<Ecm, where Ecn' is the energy level of the conduction band minimum of the barrier-free layer 14B, Eco is the energy level of the lowest unoccupied molecular orbital of the photoelectric conversion layer 15, and Ecm is the energy level of the conduction band minimum of the oxide semiconductor layer 13. The barrier-free layer 14B may be formed using, for example, the same material as the protective layer 14, or a different material.

[0139] As described above, in the photoelectric conversion section 10H of this modified example, a non-barrier layer 14B is further provided on the protective layer 14. This makes it possible to prevent oxygen from being desorbed from the oxide semiconductor layer 13 even when the protective layer 14 in the opening X1 is removed, as shown in FIG. 7, for example. Therefore, the photoelectric conversion section 10H of this modified example can obtain the same effects as those of the first embodiment.

[0140] 34 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 10I) of a photodetector element according to Modification 9 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 10I is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0141] The photoelectric conversion unit 10I of this modification further includes a stopper layer 14C as a protective layer between the oxide semiconductor layer 13 and the protective layer 14. Except for this point, the photoelectric conversion unit 10I has substantially the same configuration as the photoelectric conversion unit 10 of the first embodiment.

[0142] Like the protective layer 14, the stopper layer 14C prevents oxygen from being desorbed from the oxide semiconductor layer 13, and prevents defects from occurring on the surface of the oxide semiconductor layer 13 and in its vicinity, and is also used as an etching stopper layer when processing the protective layer 14 by, for example, dry etching or wet etching. The stopper layer 14C can be formed using a material containing one or more constituent elements different from the material constituting the protective layer 14. It is preferable that the tunnel layer 14A or the non-barrier layer 14B also serves as the stopper layer 14C.

[0143] As described above, in the photoelectric conversion unit 10I of this modification, a stopper layer 14C is further provided between the oxide semiconductor layer 13 and the protective layer 14. This makes it possible to prevent variations in characteristics caused by processing a portion of the oxide semiconductor layer 13 when processing the protective layer 14. Therefore, the photoelectric conversion unit 10H of this modification can further improve reliability.

[0144] 35 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 10J) of a photodetector element according to Modification 10 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 10J is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0145] In the photoelectric conversion unit 10J of this modification, the protective layer 14 in the opening X1 is removed, and a high carrier concentration layer 13A is formed in the oxide semiconductor layer 13 exposed at the bottom of the opening X1. Except for this point, the photoelectric conversion unit 10J has substantially the same configuration as the photoelectric conversion unit 10 of the first embodiment.

[0146] The high carrier concentration layer 13A is a layer having a carrier concentration per unit volume that is one order of magnitude or more higher than the carrier concentration of the surrounding oxide semiconductor layer 13. １７ cm －３ The high carrier concentration layer 13A has a carrier concentration of at least 1000 Å. The high carrier concentration layer 13A can be formed in a self-aligned manner by dry etching when processing the protective layer 14 to form the opening X1, or by ion implantation of, for example, aluminum (Al), tin (Sn), or indium (In). The high carrier concentration layer 13A may extend beyond the opening X1 in plan view.

[0147] As described above, in the photoelectric conversion unit 10J of this modification, the high carrier concentration layer 13A is formed in the oxide semiconductor layer 13 exposed at the bottom of the opening X1. This reduces the resistance of the oxide semiconductor layer 13 in contact with the photoelectric conversion layer 15, and therefore the photoelectric conversion unit 10J of this modification can improve the transient response between the photoelectric conversion layer 15 and the oxide semiconductor layer 13, in addition to the effects of the first embodiment.

[0148] (2-11. Modification 11) FIG. 36 is a schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 10K) of a photodetector according to Modification 11 of the present disclosure. FIG. 37 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of a photodetector device 100 including the photodetector element illustrated in FIG. 36. Note that FIG. 36 illustrates a cross section corresponding to line VI-VI illustrated in FIG. 37. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 10K is a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel section 100A of the photodetector device 100 illustrated in FIG. 109, for example. In the pixel section 100A, as illustrated in FIG. 37, a pixel unit 1a consisting of four unit pixels P arranged in two rows and two columns serves as a repeating unit, and is repeatedly arranged in an array consisting of row and column directions.

[0149] The photoelectric conversion unit 10K of this modified example has an opening H that penetrates the oxide semiconductor layer 13 between adjacent unit pixels P. Furthermore, the shield electrode 11C is omitted from the photoelectric conversion unit 10K. Except for this point, the photoelectric conversion unit 10K has substantially the same configuration as the photoelectric conversion unit 10 of the first embodiment.

[0150] The width W of the opening H is preferably, for example, 10 nm or more. It is also preferable that the storage electrode 11B and the opening H do not overlap in a plan view, and for example, the side surfaces of the storage electrode 11B and the opening H are preferably spaced apart by 10 nm or more.

[0151] As described above, in the photoelectric conversion unit 10K of this modified example, an opening H penetrating the oxide semiconductor layer 13 is provided between adjacent unit pixels P, specifically above the shield electrode 11C that was provided in the photoelectric conversion unit 10, etc., to physically separate the oxide semiconductor layer 13. This makes it possible to omit the shield electrode 11C and prevent a decrease in reliability due to constantly applying a fixed potential to the shield electrode 11C. Therefore, the photoelectric conversion unit 10K of this modified example can further improve reliability.

[0152] (2-12. Modification 12) FIG. 38 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 10L) of a photodetector element according to Modification 12 of the present disclosure. FIG. 39 is a schematic diagram illustrating another example of a cross-sectional configuration of a main part (photoelectric conversion unit 10L) of a photodetector element according to Modification 12 of the present disclosure. A photodetector element including a photoelectric conversion unit 10L is, similar to the photodetector element 1 of the first embodiment, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG. 109 .

[0153] In the photoelectric conversion unit 10L of this modification, the side and bottom surfaces of the opening H provided in the above-described modification 11 are covered with a protective layer 14D or buried in a protective layer 14. Except for this point, the photoelectric conversion unit 10L has substantially the same configuration as the photoelectric conversion unit 10K of the above-described modification 11.

[0154] Like the protective layer 14, the protective layer 14D prevents oxygen from being released from the oxide semiconductor layer 13 and prevents defects from occurring on the surface of the oxide semiconductor layer 13 and in the vicinity thereof, and is provided, for example, on the entire surface of the pixel unit 100A. Like the tunnel layer 14A and the non-barrier layer 14B, the protective layer 14D has a thickness of, for example, one atomic layer or more and 5 nm or less. The protective layer 14D may be formed, for example, using the same material as the protective layer 14, or may be formed using a different material.

[0155] In this way, in the photoelectric conversion unit 10L of this modified example, the side and bottom surfaces of the opening H are covered with the protective layer 14D or are buried in the protective layer 14. This makes it possible to prevent oxygen from being desorbed from the side surfaces of the opening H. Therefore, the reliability of the photoelectric conversion unit 10L of this modified example can be further improved.

[0156] 3. Second Embodiment FIG. 40 is a schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 60) of a photodetector (photodetector element 2) according to a second embodiment of the present disclosure. FIG. 41 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of a photodetector device 100 including the photodetector element illustrated in FIG. 40. Note that FIG. 40 illustrates a cross section corresponding to line VII-VII illustrated in FIG. 41. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 60A is a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel section 100A of the photodetector device 100 illustrated in FIG. 109, for example. In the pixel section 100A, as illustrated in FIG. 41, a pixel unit 2a, each consisting of four unit pixels P arranged in two rows and two columns, serves as a repeating unit, and is repeatedly arranged in an array consisting of row and column directions.

[0157] The photoelectric conversion unit 60 of this embodiment includes an oxide semiconductor layer 63, a protective layer 64, an electron transport layer 64A, and a photoelectric conversion layer 65 stacked in this order from the lower electrode 61 side between a lower electrode 61 and an upper electrode 66. The lower electrode 61 includes a storage electrode 61B that can store charge carriers generated by photoelectric conversion and a readout electrode 61A that reads out the charge carriers, which are spaced apart from each other. In this embodiment, the protective layer 64 has an opening X1 above at least the storage electrode 61B, which makes the protective layer 64 thinner than other regions. An electron transport layer 64A having a higher charge carrier mobility than the photoelectric conversion layer 65 is provided on the protective layer 64.

[0158] Here, the photoelectric conversion layer 65 corresponds to a specific example of a "photoelectric conversion layer" according to an embodiment of the present disclosure. The lower electrode 61 corresponds to a specific example of a "first electrode" according to an embodiment of the present disclosure. The storage electrode 61B corresponds to a specific example of a "charge storage electrode" according to an embodiment of the present disclosure, and the readout electrode 61A corresponds to a specific example of a "charge readout electrode" according to an embodiment of the present disclosure. The upper electrode 66 corresponds to a specific example of a "second electrode" according to an embodiment of the present disclosure. The oxide semiconductor layer 63 corresponds to a specific example of an "oxide semiconductor layer" according to an embodiment of the present disclosure. The protective layer 64 corresponds to a specific example of a "protective layer" according to an embodiment of the present disclosure, and the opening X1 corresponds to a specific example of an "opening" according to an embodiment of the present disclosure. The electron transport layer 64A corresponds to a specific example of an "electron transport layer" according to an embodiment of the present disclosure.

[0159] [Configuration of Photoelectric Converter] The photodetector 2 is a so-called vertical spectroscopic photodetector, similar to the photodetector 1 of the first embodiment, in which, for example, one photoelectric conversion unit 60 and two photoelectric conversion regions 32B, 32R are stacked vertically. The photoelectric conversion unit 60 is provided on the back surface (first surface 30A) of the semiconductor substrate 30. The photoelectric conversion regions 32B, 32R are embedded in the semiconductor substrate 30 and stacked in the thickness direction of the semiconductor substrate 30.

[0160] The photoelectric conversion unit 60 and the photoelectric conversion regions 32B and 32R selectively detect light in different wavelength ranges and perform photoelectric conversion. For example, the photoelectric conversion unit 60 acquires a green (G) color signal. The photoelectric conversion regions 32B and 32R acquire blue (B) and red (R) color signals, respectively, due to differences in absorption coefficients. This allows the photodetector element 2 to acquire multiple types of color signals in one pixel without using color filters.

[0161] The photoelectric conversion unit 60 is an organic photoelectric conversion element that absorbs, for example, green light corresponding to part or all of a selective wavelength range (e.g., 450 nm or more and 650 nm or less) and generates excitons. The photoelectric conversion unit 60 includes a lower electrode 61, an insulating layer 62, an oxide semiconductor layer 63, a protective layer 64, an electron transport layer 64A, a photoelectric conversion layer 65, and an upper electrode 66, stacked in this order from the semiconductor substrate 30 side. The photoelectric conversion layer 65 includes, for example, a p-type semiconductor and an n-type semiconductor, and has a bulk heterojunction structure within the layer. The bulk heterojunction structure is a p / n junction surface formed by mixing a p-type semiconductor and an n-type semiconductor.

[0162] The lower electrode 61 has, for example, a read electrode 61A and a storage electrode 61B arranged in parallel on the interlayer insulating layer 23.

[0163] The readout electrode 61A is for transferring, for example, electrons as signal charges among the charge carriers generated in the photoelectric conversion layer 65 to the floating diffusion FD1. As shown in FIG. 3 , for example, one readout electrode 61A is provided for each pixel unit 2a consisting of four unit pixels P arranged in two rows and two columns. The readout electrode 61A is connected to the floating diffusion FD1 via, for example, the upper second contact 27A, the pad portion 26A, the upper first contact 25, the pad portion 24, the through electrode 34, the connection portion 41A, and the lower second contact 46.

[0164] The storage electrode 61B is provided for each unit pixel P to store, for example, electrons as signal charges among the charge carriers generated in the photoelectric conversion layer 65. The storage electrode 61B is provided for each unit pixel P in an area that directly faces the light-receiving surfaces of the photoelectric conversion regions 32B, 32R formed in the semiconductor substrate 30 and covers these light-receiving surfaces. The storage electrode 61B is preferably larger than the readout electrode 61A, which allows it to store a large number of charge carriers. As shown in FIG. 400, the voltage application unit 48 is connected to the storage electrode 61B via wiring such as the upper third contact 27B and the pad unit 26B.

[0165] The lower electrode 61 further includes a shield electrode 61C and a transfer electrode 61D. The shield electrode 61C corresponds to a specific example of a "pixel separation electrode" according to an embodiment of the present disclosure. The shield electrode 61C is intended to prevent capacitive coupling between adjacent pixel units 2a. The shield electrode 61C is provided, for example, between adjacent pixel units 2a, and a fixed potential is applied to the shield electrode 61C. The shield electrode 61C further extends between adjacent pixels in the row direction (Y-axis direction) and column direction (X-axis direction) of four unit pixels P arranged in a 2-row by 2-column matrix that constitute the pixel unit 2a, as shown in FIG. 3 . The transfer electrode 61D controls the energy potential of the oxide semiconductor layer 13 between the readout electrode 61A and the storage electrode 61B, thereby controlling the flow of charge carriers stored in the oxide semiconductor layer 13 above the storage electrode 61B to the readout electrode 211. The transfer electrode 61D is individually provided between the readout electrode 61A disposed substantially in the center of the pixel unit 2a and the four storage electrodes 61B provided for each unit pixel P, for example.

[0166] The lower electrode 61 is made of, for example, a light-transmitting conductive film. The lower electrode 61 preferably has a work function of, for example, 4.0 eV or more and 5.5 eV or less. The constituent material of such a lower electrode 61 is, for example, InP doped with tin (Sn) as a dopant. ２ O ３ The ITO film may have high or low crystallinity (close to amorphous). In addition to the above, the lower electrode 61 may also be made of tin oxide (SnO ２)-based materials, for example, ATO with antimony (Sb) added as a dopant, and FTO with fluorine (F) added as a dopant may be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added thereto may also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO ４ The lower electrode 61 may be made of CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0167] When the lower electrode 61 does not need to be optically transparent (for example, when light is incident from the upper electrode 66 side and the photoelectric conversion regions 32R and 32B are not provided below the storage electrode 61B), a single metal or alloy having a small work function (for example, φ=3.5 eV to 4.5 eV) can be used. Specific examples include alkali metals (for example, lithium (Li), sodium (Na), and potassium (K)) and their fluorides or oxides, and alkaline earth metals (for example, magnesium (Mg) and calcium (Ca)) and their fluorides or oxides. Other examples include rare earth metals such as aluminum (Al), Al—Si—Cu alloys, zinc (Zn), tin (Sn), thallium (Tl), Na—K alloys, Al—Li alloys, Mg—Ag alloys, In, and ytterbium (Yb), or alloys thereof.

[0168] Examples of materials that can be used to form the lower electrode 61 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), and molybdenum (Mo), alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials that can be used to form the lower electrode 61 include organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT / PSS). Alternatively, the above materials can be mixed with a binder (polymer) to form a paste or ink, which can then be cured and used as an electrode.

[0169] The lower electrode 61 can be formed as a single layer or a laminated film made of the above materials. The film thickness of the lower electrode 61 in the lamination direction (hereinafter simply referred to as thickness) is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0170] The insulating layer 62 serves to electrically separate the storage electrode 61B from the oxide semiconductor layer 63. The insulating layer 62 is provided, for example, on the interlayer insulating layer 23 so as to cover the lower electrode 61. An opening 62H is provided in the insulating layer 62 above the readout electrode 61A of the lower electrode 61, and the readout electrode 61A and the oxide semiconductor layer 63 are electrically connected via this opening 62H. The insulating layer 62 is made of, for example, silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ The insulating layer 62 is made of a single layer film made of one of silicon oxynitride (SiON) and silicon oxynitride (SiON), or a laminated film made of two or more of these materials. The thickness of the insulating layer 62 is, for example, 20 nm to 500 nm.

[0171] The oxide semiconductor layer 63 is for accumulating charge carriers generated in the photoelectric conversion layer 65. The oxide semiconductor layer 63 can be formed using an oxide semiconductor containing at least one element selected from the group consisting of indium (In), gallium (Ga), zinc (Zn), aluminum (Al), and tin (Sn). In this embodiment, electrons among the charge carriers generated in the photoelectric conversion layer 65 are used as signal charges. For this reason, the oxide semiconductor layer 63 can be formed using an n-type oxide semiconductor material. Specifically, the oxide semiconductor layer 63 can be formed using IGZO (In—Ga—Zn—O-based oxide semiconductor), gallium oxide (Ga ２ O ３ ), ZTO (Zn—Sn—O-based oxide semiconductor), IZO (In—Zn—O-based oxide semiconductor), ITO, indium gallium aluminum oxide (InGaAlO), and indium gallium silicon oxide (InGaSiO). The thickness of the oxide semiconductor layer 63 is, for example, 10 nm to 300 nm.

[0172] The protective layer 64 prevents oxygen from being released from the oxide semiconductor layer 63 and prevents defects from occurring on the surface of the oxide semiconductor layer 63 and in its vicinity. As described above, the protective layer 64 has an opening X1 above the storage electrode 61B, which makes the protective layer 64 thinner than other regions. The opening X1 has, for example, an area equal to or greater than half the area of ​​the storage electrode 61B in a plan view. In other words, the protective layer 64 has an opening X1 and a non-opening X2 in the XY plane. The opening X1 is formed above the storage electrode 61B and has an area equal to or greater than half the area of ​​the storage electrode 61B, as shown in FIG. 3 . The thickness of the protective layer 64 in the non-opening X2 is, for example, 1 nm or more and 100 nm or less. The thickness of the protective layer 64 in the opening X1 is thinner than the thickness of the protective layer 64 in the non-opening X2, for example, 0 nm or more and 5 nm or less.

[0173] The protective layer 64 can be formed using, for example, an oxide or nitride containing at least one of silicon (Si), germanium (Ge), aluminum (Al), hafnium (Hf), lanthanum (La), strontium (Sr), zirconium (Zr), vanadium (V), tantalum (Ta), titanium (Ti), yttrium (Y), magnesium (Mg), carbon (C), tin (Sn), erbium (Er), ytterbium (Yb), and gadolinium (Gd).

[0174] The electron transport layer 64A is for collecting charge carriers remaining on the non-opening portion X2. As described above, the electron transport layer 64A has a higher mobility of charge carriers than the photoelectric conversion layer 65. For example, －３ cm ２ / Vs or more 100cm ２ / Vs or less.

[0175] 42 shows an example of the energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the electron transport layer 64A, the photoelectric conversion layer 65, and the upper electrode 66 at the opening X1 corresponding to the line A-A' in FIG. 40 . FIG. 43 shows an example of the energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the protective layer 64, the electron transport layer 64A, the photoelectric conversion layer 65, and the upper electrode 66 at the non-opening X2 corresponding to the line B-B' in FIG. 40 . Here, with the vacuum level as the zero reference, the energy is defined as being greater (deeper) as the distance from the vacuum level, and smaller (shallower) as the distance from the vacuum level. When the energy level of the conduction band minimum of the electron transport layer 64A is Ece and the energy level of the conduction band minimum of the oxide semiconductor layer 63 is Ecm, the energy levels of the conduction band minimum of the electron transport layer and the conduction band minimum of the oxide semiconductor layer preferably satisfy the relationship of the following mathematical formula (1): This allows charge carriers (electrons) generated in the photoelectric conversion layer 65 to be transported to the oxide semiconductor layer 63 without being hindered by the electron transport layer 64A. (Equation 1) |Ece|-|Ecm|≦0.3 (1)

[0176] The electron transport layer 64A can be formed using, for example, an n-type inorganic semiconductor material. Specific examples of materials for the electron transport layer 64A include IGZO (In—Ga—Zn—O-based oxide semiconductor), zinc oxide (ZnO), and ITO. From the viewpoint of electron transport properties, the thickness of the electron transport layer 64A is preferably, for example, 0.5 nm to 100 nm.

[0177] 43 shows an example in which the electron transport layer 64A is provided over the entire surface of the pixel unit 100A, but the present invention is not limited to this. For example, as shown in FIG. 44, the electron transport layer 64A may be formed only in the non-opening portion X2 of the protective layer 64. For example, as shown in FIG. 45, the electron transport layer 64A may cover the upper and side surfaces of the non-opening portion X2 of the protective layer 64 and an upper portion of the storage electrode 61B. For example, as shown in FIG. 46, the electron transport layer 64A may cover a portion of the upper surface of the non-opening portion X2 of the protective layer 64.

[0178] The photoelectric conversion layer 65 converts light energy into electrical energy. The photoelectric conversion layer 65 is configured, for example, by including two or more organic materials (p-type semiconductor materials or n-type semiconductor materials) that function as p-type or n-type semiconductors, respectively. The photoelectric conversion layer 65 has a junction surface (p / n junction surface) between a p-type semiconductor material and an n-type semiconductor material within the layer. The p-type semiconductor functions relatively as an electron donor, and the n-type semiconductor functions relatively as an electron acceptor. The photoelectric conversion layer 65 provides a site where excitons generated upon light absorption separate into electrons and holes. Specifically, the excitons separate into electrons and holes at the interface (p / n junction surface) between the electron donor and electron acceptor.

[0179] In addition to the p-type and n-type semiconductor materials, the photoelectric conversion layer 65 may also contain an organic material, a so-called dye material, that photoelectrically converts light in a predetermined wavelength range while transmitting light in other wavelength ranges. When the photoelectric conversion layer 65 is formed using three types of organic materials, i.e., a p-type semiconductor material, an n-type semiconductor material, and a dye material, the p-type and n-type semiconductor materials are preferably materials that are optically transparent in the visible range (e.g., 450 nm to 800 nm). The thickness of the photoelectric conversion layer 65 is, for example, 50 nm to 500 nm.

[0180] Examples of organic materials that can be used to form the photoelectric conversion layer 65 include quinacridone derivatives, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluoranthene derivatives. The photoelectric conversion layer 65 is formed by combining two or more of the above organic materials. Depending on the combination, the above organic materials function as p-type or n-type semiconductors.

[0181] There are no particular limitations on the organic material that constitutes the photoelectric conversion layer 65. Examples of organic materials that can be used to constitute the photoelectric conversion layer 65 include polymers of phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, and derivatives thereof. Examples of organic materials that can be used to form the photoelectric conversion layer 65 include metal complex dyes, cyanine dyes, merocyanine dyes, phenylxanthene dyes, triphenylmethane dyes, rhodacyanine dyes, xanthene dyes, macrocyclic azaannulene dyes, azulene dyes, naphthoquinone dyes, anthraquinone dyes, condensed polycyclic aromatic compounds such as pyrene, chain compounds formed by condensing aromatic rings or heterocyclic compounds, quinolines having a squarylium group and a croconite methine group as a bonding chain, benzothiazoles, benzoxazoles, and other nitrogen-containing heterocycles, or cyanine-like dyes bonded by a squarylium group and a croconite methine group. Metal complex dyes include dithiol metal complex dyes, metal phthalocyanine dyes, metal porphyrin dyes, and ruthenium complex dyes. Among these, ruthenium complex dyes are particularly preferred, but are not limited to these. However, the photoelectric conversion layer 65 may be made of quantum dots or the like in addition to the organic material.

[0182] The upper electrode 66 is made of, for example, a light-transmitting conductive film, similar to the lower electrode 61. The upper electrode 66 is made of, for example, InP doped with Sn. ２ O ３ The crystallinity of the ITO film may be high or low (close to amorphous). In addition to the above, the upper electrode 66 may be made of SnO ２Examples of the ZnO-based material include ATO with Sb added as a dopant and FTO with fluorine added as a dopant. ZnO or a zinc oxide-based material with a dopant added may also be used. Examples of the ZnO-based material include AZO with Al added as a dopant, GZO with Ga added, boron zinc oxide with B added, and IZO with In added. IGZO (In-GaZnO4) may also be used with indium and gallium added as dopants. Examples of the material for the lower electrode 61 include CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0183] Furthermore, if optical transparency is not required for the upper electrode 66, a single metal or alloy having a large work function (for example, φ=4.5 eV to 5.5 eV) can be used. Specific examples include Au, Ag, Cr, Ni, Pd, Pt, Fe, iridium (Ir), germanium (Ge), osmium (Os), rhenium (Re), tellurium (Te), and alloys thereof.

[0184] Furthermore, examples of materials that can be used to form the upper electrode 66 include metals such as Pt, Au, Pd, Cr, Ni, Al, Ag, Ta, W, Cu, Ti, In, Sn, Fe, Co, and Mo, alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials that can be used to form the upper electrode 66 include organic materials (conductive polymers) such as PEDOT / PSS. Alternatively, the above materials can be mixed with a binder (polymer) to form a paste or ink, which can then be hardened and used as an electrode.

[0185] The upper electrode 66 can be formed as a single layer or a laminated film made of the above materials. The thickness of the upper electrode 66 is, for example, 20 nm to 200 nm, preferably 30 nm to 150 nm.

[0186] The photoelectric conversion unit 60 may have other layers between the lower electrode 61 and the photoelectric conversion layer 65 and between the photoelectric conversion layer 65 and the upper electrode 66. For example, a hole blocking layer may be provided between the lower electrode 61 and the photoelectric conversion layer 65. The hole blocking layer prevents holes from moving from the lower electrode 61 to the photoelectric conversion layer 65 and efficiently transports electrons, among the charge carriers generated in the photoelectric conversion layer 65, to the lower electrode 61. An electron blocking layer or a work function adjustment layer may be provided between the photoelectric conversion layer 65 and the upper electrode 66. The electron blocking layer prevents electrons from moving from the upper electrode 66 to the photoelectric conversion layer 65 and efficiently transports holes, among the charge carriers generated in the photoelectric conversion layer 65, to the upper electrode 66. The work function adjustment layer has an electron affinity or work function greater than the work function of the upper electrode 66 and improves the electrical connection between the photoelectric conversion layer 65 and the upper electrode 66.

[0187] The photoelectric conversion layer 65 may also have a pin bulk heterostructure in which, for example, a p-type blocking layer, a layer containing p-type and n-type semiconductors (i-layer), and an n-type blocking layer are stacked.

[0188] [Functions and Effects] In the photodetector element 2 of this embodiment, in the photoelectric conversion unit 10 in which the oxide semiconductor layer 63, the protective layer 64, and the photoelectric conversion layer 65 are stacked in this order from the lower electrode 61 side between the lower electrode 61 and the upper electrode 66, an opening X1 is formed in the protective layer 64 above the storage electrode 61B constituting the lower electrode 61, the opening X1 having a smaller film thickness than other regions (non-openings X2), and further, an electron transport layer 64A having a higher charge carrier mobility than the photoelectric conversion layer 65 is provided so as to cover the top and side surfaces of the protective layer 14. This suppresses the formation of oxygen defects in the oxide semiconductor layer 63 without preventing the movement of charge carriers generated in the photoelectric conversion layer 65 by photoelectric conversion to the oxide semiconductor layer 63, and further makes it possible to collect charge carriers remaining in the non-openings X2.

[0189] As a result, in the photodetector element 2 of this embodiment, it is possible to improve reliability, prevent a decrease in external quantum efficiency due to charge carriers remaining on the non-opening portion X2, and improve sensitivity.

[0190] 47 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 60A) of a photodetector element according to Modification 13 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 60A is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0191] The photoelectric conversion section 60A of this modification further includes a tunnel layer 64B as a protective layer on the electron transport layer 64A. Except for this, the photoelectric conversion section 60A has substantially the same configuration as the photoelectric conversion section 60 of the second embodiment.

[0192] Fig. 48 shows an example of energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the electron transport layer 64A, the tunnel layer 64B, the photoelectric conversion layer 65, and the upper electrode 66 at the opening X1 corresponding to the line A-A' shown in Fig. 47. Fig. 49 shows an example of energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the protective layer 64, the electron transport layer 64A, the tunnel layer 64B, the photoelectric conversion layer 65, and the upper electrode 66 at the non-opening X2 corresponding to the line B-B' shown in Fig. 47. The tunnel layer 64B, like the protective layer 64, prevents oxygen from being released from the oxide semiconductor layer 63 and prevents defects from occurring on the surface of the oxide semiconductor layer 63 and in the vicinity thereof, and is provided, for example, over the entire surface of the pixel unit 100A. The tunnel layer 64B satisfies Ecn'<Eco or Ecn'<Ecm, for example, where Ecn' is the energy level of the conduction band minimum of the tunnel layer 64B, Eco is the energy level of the lowest unoccupied molecular orbital of the photoelectric conversion layer 65, and Ecm is the energy level of the conduction band minimum of the oxide semiconductor layer 63, and has a thickness of, for example, one atomic layer or more and 5 nm or less. The tunnel layer 64B may be formed using, for example, the same material as the protective layer 64, or may be formed using a different material.

[0193] As described above, in the photoelectric conversion unit 60A of this modification, a tunnel layer 64B is further provided on the electron transport layer 64A. This makes it possible to prevent oxygen from being released from the electron transport layer 64A containing an inorganic semiconductor material. Therefore, the photoelectric conversion unit 60A of this modification can reduce noise in addition to the effects of the second embodiment.

[0194] 50 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 60B) of a photodetector element according to Modification 14 of the present disclosure. Similar to photodetector element 1 of the first embodiment, a photodetector element including photoelectric conversion unit 60B is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in pixel unit 100A of photodetector device 100 shown in FIG.

[0195] Although the above-described modification 13 shows an example in which the electron transport layer 64A and the tunnel layer 64B are stacked in this order on the protective layer 64, the present invention is not limited to this. The photoelectric conversion section 60B of this modification has the tunnel layer 64B and the electron transport layer 64A stacked in this order on the protective layer 64. Except for this point, the photoelectric conversion section 60B has substantially the same configuration as the photoelectric conversion section 60 of the above-described second embodiment.

[0196] Fig. 51 shows an example of energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the tunnel layer 64B, the electron transport layer 64A, the photoelectric conversion layer 65, and the upper electrode 66 at the opening X1 corresponding to the line A-A' shown in Fig. 47. Fig. 52 shows an example of energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the protective layer 64, the tunnel layer 64B, the electron transport layer 64A, the photoelectric conversion layer 65, and the upper electrode 66 at the non-opening X2 corresponding to the line B-B' shown in Fig. 47.

[0197] Even with this configuration, the photoelectric conversion unit 60B of this modification can achieve the same effects as the photoelectric conversion unit 60A of the thirteenth modification.

[0198] 53 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 60C) of a photodetector element according to Modification 15 of the present disclosure. Similar to photodetector element 1 of the first embodiment, a photodetector element including photoelectric conversion unit 60C is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in pixel unit 100A of photodetector device 100 shown in FIG.

[0199] In the photoelectric conversion section 60C of this modified example, instead of the above-described electron transport layer 64A, an electron transport layer 64C made of an organic semiconductor material having a higher charge carrier mobility than the photoelectric conversion layer 65 is provided on the protective layer 64. Except for this point, the photoelectric conversion section 60A has substantially the same configuration as the photoelectric conversion section 60 of the second embodiment.

[0200] The electron transport layer 64C, like the electron transport layer 64A, serves to collect charge carriers remaining on the non-opening portion X2. The electron transport layer 64C is made of an organic semiconductor material as described above, and has anisotropic mobility. Specifically, the electron transport layer 64C has a higher mobility of charge carriers in the in-plane direction than in the film thickness direction. The electron transport layer 64C has a thickness of, for example, 10 －３ cm ２ / Vs or more 100cm ２ / Vs or less.

[0201] 54 shows an example of the energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the electron transport layer 64C, the photoelectric conversion layer 65, and the upper electrode 66 at the opening X1 corresponding to the line A-A' in FIG. 53 . FIG. 55 shows an example of the energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the protective layer 64, the electron transport layer 64C, the photoelectric conversion layer 65, and the upper electrode 66 at the non-opening X2 corresponding to the line B-B' in FIG. 53 . Here, with the vacuum level as the zero reference, the farther from the vacuum level the greater (deeper) the energy, and the closer to the vacuum level the smaller (shallower) the energy. When the energy level of the lowest unoccupied molecular orbital of the electron transport layer 64C is Ece' and the energy level of the conduction band minimum of the oxide semiconductor layer 63 is Ecm, the energy levels of the conduction band minimum of the electron transport layer and the conduction band minimum of the oxide semiconductor layer preferably satisfy the relationship of the following mathematical formula (2): This allows charge carriers (electrons) generated in the photoelectric conversion layer 65 to be transported to the oxide semiconductor layer 63 without being hindered by the electron transport layer 64C. |Ece′|−|Ecm|≦0.3 (2)

[0202] Examples of materials for the electron transport layer 64C include fullerene C60 and perylene derivatives. From the viewpoint of electron transport properties, the thickness of the electron transport layer 64C is preferably, for example, 3 nm or more and 100 nm or less. The surface of the protective layer 64 on which the electron transport layer 64C is formed may be hydrophobicized with a self-assembled monolayer.

[0203] In this manner, in the photoelectric conversion unit 60C of this modified example, the upper surface and side surfaces of the protective layer 14 are covered with the electron transport layer 64C made of an organic semiconductor material. Even with this configuration, the photoelectric conversion unit 60C of this modified example can obtain the same effects as the photodetector element 2 of the second embodiment.

[0204] 56 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 60D) of a photodetector element according to Modification 16 of the present disclosure. Similar to photodetector element 1 of the first embodiment, a photodetector element including photoelectric conversion unit 60D is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in pixel unit 100A of photodetector device 100 shown in FIG.

[0205] The photoelectric conversion unit 60D of this modification has, instead of the above-described electron transport layer 64A, an electron transport layer 64D made of an organic semiconductor material having a higher charge carrier mobility than the photoelectric conversion layer 65 and having a highest occupied molecular orbital (HOMO) that is the same as or higher than that of the photoelectric conversion layer 65, provided on the protective layer 64. Except for this point, the photoelectric conversion unit 60D has substantially the same configuration as the photoelectric conversion unit 60 of the second embodiment and the photoelectric conversion unit 60C of modification 15.

[0206] The electron transport layer 64D, like the electron transport layer 64C, is for collecting charge carriers remaining on the non-opening portion X2, and is made of an organic semiconductor material as described above, and has anisotropic mobility. Specifically, the electron transport layer 64D has a higher mobility of charge carriers in the in-plane direction than in the film thickness direction. The electron transport layer 64D is, for example, 10 －３ cm ２ / Vs or more 100cm ２ / Vs or less.

[0207] Fig. 57 shows an example of energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the electron transport layer 64D, the photoelectric conversion layer 65, and the upper electrode 66 at the opening X1 corresponding to the line A-A' shown in Fig. 56. Fig. 58 shows an example of energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the protective layer 64, the electron transport layer 64D, the photoelectric conversion layer 65, and the upper electrode 66 at the non-opening X2 corresponding to the line B-B' shown in Fig. 56. Here, with the vacuum level as the zero reference, the energy is defined as being larger (deeper) as it moves away from the vacuum level, and as it moves closer to the vacuum level, the energy is defined as being smaller (shallower). When the HOMO energy level of the electron transport layer 64D is Eve' and the HOMO energy level of the photoelectric conversion layer 65 is Evo, the HOMO energy level of the electron transport layer 64D and the HOMO energy level of the photoelectric conversion layer 65 satisfy the relationship of the following mathematical formula (3). As a result, the charge carriers (electrons) remaining on the non-opening X2 are pushed out by the holes accumulated near the interface between the protective layer 64 and the electron transport layer 64D, as shown in FIG. 58 . (Mathematical formula 3) |Evo|-|Eve'|≧0 (3)

[0208] The electron transport layer 64D can be formed as a mixed film of, for example, fullerene C60 and fluorinated phthalocyanine. From the viewpoint of electron transport properties, the thickness of the electron transport layer 64D is preferably, for example, 3 nm to 100 nm.

[0209] As described above, in the photoelectric conversion unit 60D of this modified example, the top and side surfaces of the protective layer 14 are covered with an electron transport layer 64D made of an organic semiconductor material and having a HOMO that is the same as or higher than the HOMO of the photoelectric conversion layer 65. Even with this configuration, the photoelectric conversion unit 60D of this modified example can achieve the same effects as the photodetector element 2 of the second embodiment.

[0210] 59 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 60E) of a photodetector element according to Modification 17 of the present disclosure. Similar to photodetector element 1 of the first embodiment, a photodetector element including photoelectric conversion unit 60E is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in pixel unit 100A of photodetector device 100 shown in FIG.

[0211] The photoelectric conversion unit 60E of this modification further includes a tunnel layer 64B between the protective layer 64 and the electron transport layer 64C. Except for this point, the photoelectric conversion unit 60E has substantially the same configuration as the photoelectric conversion unit 60B of the above-described modification 14 and the photoelectric conversion unit 60C of modification 15.

[0212] Fig. 60 shows an example of energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the tunnel layer 64B, the electron transport layer 64C, the photoelectric conversion layer 65, and the upper electrode 66 at the opening X1 corresponding to the line A-A' shown in Fig. 59. Fig. 61 shows an example of energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the protective layer 64, the tunnel layer 64B, the electron transport layer 64C, the photoelectric conversion layer 65, and the upper electrode 66 at the non-opening X2 corresponding to the line B-B' shown in Fig. 59.

[0213] Even with this configuration, the photoelectric conversion unit 60E of this modification can obtain the same effects as the photoelectric conversion unit 60C of the fifteenth modification.

[0214] 62 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 60F) of a photodetector element according to Modification 18 of the present disclosure. Similar to photodetector element 1 of the first embodiment, a photodetector element including photoelectric conversion unit 60F is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in pixel unit 100A of photodetector device 100 shown in FIG.

[0215] The photoelectric conversion unit 60F of this modification further includes a tunnel layer 64B between the protective layer 64 and the electron transport layer 64D. Except for this point, the photoelectric conversion unit 60F has substantially the same configuration as the photoelectric conversion unit 60B of the above-described modification 14 and the photoelectric conversion unit 60D of modification 16.

[0216] Fig. 63 shows an example of energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the electron transport layer 64D, the tunnel layer 64B, the photoelectric conversion layer 65, and the upper electrode 66 at the opening X1 corresponding to the line A-A' shown in Fig. 62. Fig. 64 shows an example of energy levels of the storage electrode 61B, the insulating layer 62, the oxide semiconductor layer 63, the protective layer 64, the electron transport layer 64D, the tunnel layer 64B, the photoelectric conversion layer 65, and the upper electrode 66 at the non-opening X2 corresponding to the line B-B' shown in Fig. 62.

[0217] Even with this configuration, the photoelectric conversion unit 60F of this modification can obtain the same effects as the photoelectric conversion unit 60D of the sixteenth modification.

[0218] 5. Third Embodiment FIG. 65 is a schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 70) of a photodetector (photodetector element 3) according to a third embodiment of the present disclosure. FIG. 66 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of a photodetector device 100 including the photodetector element illustrated in FIG. 65. Note that FIG. 65 illustrates a cross section corresponding to line VIII-VIII illustrated in FIG. 66. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 70A is a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel section 100A of the photodetector device 100 illustrated in FIG. 109, for example. In the pixel section 100A, as illustrated in FIG. 66, a pixel unit 3a, each consisting of four unit pixels P arranged in two rows and two columns, serves as a repeating unit, and is repeatedly arranged in an array consisting of row and column directions.

[0219] The photoelectric conversion unit 70 of this embodiment includes an oxide semiconductor layer 73, a protective layer 74, and a photoelectric conversion layer 75 stacked in this order from the lower electrode 71 side between a lower electrode 71 and an upper electrode 76. The lower electrode 71 includes a storage electrode 71B that can store charge carriers generated by photoelectric conversion and a readout electrode 71A that reads out the charge carriers, which are spaced apart from each other. In this embodiment, the protective layer 74 has an opening X1 above at least the storage electrode 71B, which has a smaller film thickness than other regions (non-openings X2). An insulating portion 75X is formed in the photoelectric conversion layer 75 above the non-openings X2.

[0220] Here, the photoelectric conversion layer 75 corresponds to a specific example of a "photoelectric conversion layer" according to an embodiment of the present disclosure. The lower electrode 71 corresponds to a specific example of a "first electrode" according to an embodiment of the present disclosure. The storage electrode 71B corresponds to a specific example of a "charge storage electrode" according to an embodiment of the present disclosure, and the readout electrode 71A corresponds to a specific example of a "charge readout electrode" according to an embodiment of the present disclosure. The upper electrode 76 corresponds to a specific example of a "second electrode" according to an embodiment of the present disclosure. The oxide semiconductor layer 73 corresponds to a specific example of an "oxide semiconductor layer" according to an embodiment of the present disclosure. The protective layer 74 corresponds to a specific example of a "protective layer" according to an embodiment of the present disclosure, and the opening X1 corresponds to a specific example of an "opening" according to an embodiment of the present disclosure. The insulating portion 75X corresponds to a specific example of an "insulating portion" according to an embodiment of the present disclosure.

[0221] [Configuration of Photoelectric Converter] The photodetector 3 is, similar to the photodetector 1 of the first embodiment, a so-called vertical spectroscopic photodetector in which, for example, one photoelectric conversion unit 70 and two photoelectric conversion regions 32B, 32R are stacked vertically. The photoelectric conversion unit 70 is provided on the back surface (first surface 30A) of the semiconductor substrate 30. The photoelectric conversion regions 32B, 32R are embedded in the semiconductor substrate 30 and stacked in the thickness direction of the semiconductor substrate 30.

[0222] The photoelectric conversion unit 70 and the photoelectric conversion regions 32B and 32R selectively detect light in different wavelength ranges and perform photoelectric conversion. For example, the photoelectric conversion unit 70 acquires a green (G) color signal. The photoelectric conversion regions 32B and 32R acquire blue (B) and red (R) color signals, respectively, due to differences in absorption coefficients. This allows the photodetector 3 to acquire multiple types of color signals in one pixel without using color filters.

[0223] The photoelectric conversion unit 70 is an organic photoelectric conversion element that absorbs, for example, green light corresponding to part or all of a selective wavelength range (e.g., 450 nm or more and 650 nm or less) and generates excitons. The photoelectric conversion unit 70 includes a lower electrode 71, an insulating layer 72, an oxide semiconductor layer 73, a protective layer 74, a tunnel layer 74A, a photoelectric conversion layer 75, and an upper electrode 76 stacked in this order from the semiconductor substrate 30 side. The photoelectric conversion layer 75 includes, for example, a p-type semiconductor and an n-type semiconductor, and has a bulk heterojunction structure within the layer. The bulk heterojunction structure is a p / n junction surface formed by mixing a p-type semiconductor and an n-type semiconductor.

[0224] The lower electrode 71 has, for example, a read electrode 71A and a storage electrode 71B arranged in parallel on the interlayer insulating layer 23.

[0225] The readout electrode 71A is for transferring, for example, electrons as signal charges among the charge carriers generated in the photoelectric conversion layer 75 to the floating diffusion FD1. As shown in FIG. 3 , for example, one readout electrode 71A is provided for each pixel unit 3a, which is made up of four unit pixels P arranged in two rows and two columns. The readout electrode 71A is connected to the floating diffusion FD1 via, for example, the upper second contact 27A, the pad portion 26A, the upper first contact 25, the pad portion 24, the through electrode 34, the connection portion 41A, and the lower second contact 46.

[0226] The storage electrode 71B is provided for each unit pixel P to store, for example, electrons as signal charges among the charge carriers generated in the photoelectric conversion layer 75. The storage electrode 71B is provided for each unit pixel P in an area that directly faces the light-receiving surfaces of the photoelectric conversion regions 32B, 32R formed in the semiconductor substrate 30 and covers these light-receiving surfaces. The storage electrode 71B is preferably larger than the readout electrode 71A, which allows it to store a large number of charge carriers. As shown in FIG. 650, the voltage application unit 48 is connected to the storage electrode 71B via wiring such as the upper third contact 27B and the pad unit 26B.

[0227] The lower electrode 71 further includes a shield electrode 71C and a transfer electrode 71D. The shield electrode 71C corresponds to a specific example of a "pixel separation electrode" according to an embodiment of the present disclosure. The shield electrode 71C is intended to prevent capacitive coupling between adjacent pixel units 3a. The shield electrode 71C is provided, for example, between adjacent pixel units 3a and has a fixed potential applied thereto. The shield electrode 71C further extends between adjacent pixels in the row direction (Y-axis direction) and column direction (X-axis direction) of four unit pixels P arranged in a 2-row by 2-column matrix that constitute the pixel unit 3a, as shown in FIG. 3 . The transfer electrode 71D controls the energy potential of the oxide semiconductor layer 13 between the readout electrode 71A and the storage electrode 71B, thereby controlling the flow of charge carriers stored in the oxide semiconductor layer 13 above the storage electrode 71B to the readout electrode 211. The transfer electrodes 71D are individually provided between the readout electrode 71A disposed substantially in the center of the pixel unit 3a and the four storage electrodes 71B provided for each unit pixel P, for example.

[0228] The lower electrode 71 is made of, for example, a conductive film having optical transparency. The lower electrode 71 preferably has a work function of, for example, 4.0 eV or more and 5.5 eV or less. The constituent material of such a lower electrode 71 is, for example, InP doped with tin (Sn) as a dopant. ２ O ３The ITO film may have high or low crystallinity (close to amorphous). In addition to the above, the lower electrode 71 may also be made of a material such as tin oxide (SnO ２ )-based materials, for example, ATO with antimony (Sb) added as a dopant, and FTO with fluorine (F) added as a dopant may be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added thereto may also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO ４ The lower electrode 71 may be made of CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0229] When the lower electrode 71 does not need to be optically transparent (for example, when light is incident from the upper electrode 76 side and the photoelectric conversion regions 32R and 32B are not provided below the storage electrode 71B), a single metal or alloy having a small work function (for example, φ=3.5 eV to 4.5 eV) can be used. Specific examples include alkali metals (for example, lithium (Li), sodium (Na), and potassium (K)) and their fluorides or oxides, and alkaline earth metals (for example, magnesium (Mg) and calcium (Ca)) and their fluorides or oxides. Other examples include rare earth metals such as aluminum (Al), Al—Si—Cu alloys, zinc (Zn), tin (Sn), thallium (Tl), Na—K alloys, Al—Li alloys, Mg—Ag alloys, In, and ytterbium (Yb), or alloys thereof.

[0230] Examples of materials that can be used to form the lower electrode 71 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), and molybdenum (Mo), alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials that can be used to form the lower electrode 71 include organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT / PSS). Alternatively, the above materials can be mixed with a binder (polymer) to form a paste or ink, which can then be cured and used as an electrode.

[0231] The lower electrode 71 can be formed as a single layer or a laminated film made of the above materials. The film thickness of the lower electrode 71 in the lamination direction (hereinafter simply referred to as thickness) is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0232] The insulating layer 72 serves to electrically separate the storage electrode 71B from the oxide semiconductor layer 73. The insulating layer 72 is provided, for example, on the interlayer insulating layer 23 so as to cover the lower electrode 71. An opening 62H is provided in the insulating layer 72 above the readout electrode 71A of the lower electrode 71, and the readout electrode 71A and the oxide semiconductor layer 73 are electrically connected via this opening 62H. The insulating layer 72 is made of, for example, silicon oxide (SiO ｘ ), silicon nitride (SiN ｘ The insulating layer 72 is made of a single layer film made of one of silicon oxynitride (SiON) and silicon oxynitride (SiON), or a laminated film made of two or more of these materials. The thickness of the insulating layer 72 is, for example, 20 nm to 500 nm.

[0233] The oxide semiconductor layer 73 is for accumulating charge carriers generated in the photoelectric conversion layer 75. The oxide semiconductor layer 73 can be formed using an oxide semiconductor containing at least one element selected from the group consisting of indium (In), gallium (Ga), zinc (Zn), aluminum (Al), and tin (Sn). In this embodiment, electrons among the charge carriers generated in the photoelectric conversion layer 75 are used as signal charges. For this reason, the oxide semiconductor layer 73 can be formed using an n-type oxide semiconductor material. Specifically, the oxide semiconductor layer 73 can be formed using IGZO (In—Ga—Zn—O-based oxide semiconductor), gallium oxide (Ga ２ O ３ ), ZTO (Zn—Sn—O-based oxide semiconductor), IZO (In—Zn—O-based oxide semiconductor), ITO, indium gallium aluminum oxide (InGaAlO), and indium gallium silicon oxide (InGaSiO). The oxide semiconductor layer 73 has a thickness of, for example, 10 nm to 300 nm.

[0234] The protective layer 74 prevents oxygen from being released from the oxide semiconductor layer 73 and prevents defects from occurring on the surface of the oxide semiconductor layer 73 and in its vicinity. As described above, the protective layer 74 has an opening X1 above the storage electrode 71B, which makes the protective layer 74 thinner than other regions. The opening X1 has, for example, an area equal to or greater than half the area of ​​the storage electrode 71B in a plan view. In other words, the protective layer 74 has an opening X1 and a non-opening X2 in the XY plane. The opening X1 is formed above the storage electrode 71B and has an area equal to or greater than half the area of ​​the storage electrode 71B, as shown in FIG. 3 . The thickness of the protective layer 74 in the non-opening X2 is, for example, 1 nm or more and 100 nm or less. The thickness of the protective layer 74 in the opening X1 is thinner than the thickness of the protective layer 74 in the non-opening X2, for example, 0 nm or more and 5 nm or less.

[0235] The protective layer 74 can be formed using, for example, an oxide or nitride containing at least one of silicon (Si), germanium (Ge), aluminum (Al), hafnium (Hf), lanthanum (La), strontium (Sr), zirconium (Zr), vanadium (V), tantalum (Ta), titanium (Ti), yttrium (Y), magnesium (Mg), carbon (C), tin (Sn), erbium (Er), ytterbium (Yb), and gadolinium (Gd).

[0236] Like the protective layer 74, the tunnel layer 74A prevents oxygen from being released from the oxide semiconductor layer 73 and prevents defects from occurring on the surface of the oxide semiconductor layer 73 and in its vicinity, and is provided, for example, on the entire surface of the pixel unit 100A. For example, when the energy level of the conduction band minimum of the tunnel layer 74A is Ecn', the energy level of the lowest unoccupied molecular orbital of the photoelectric conversion layer 75 is Eco, and the energy level of the conduction band minimum of the oxide semiconductor layer 73 is Ecm, the tunnel layer 74A satisfies Ecn'<Eco or Ecn'<Ecm and has a thickness of, for example, one atomic layer or more and 5 nm or less. For example, the tunnel layer 74A may be formed using the same material as the protective layer 74, or may be formed using a different material.

[0237] The photoelectric conversion layer 75 converts light energy into electrical energy. The photoelectric conversion layer 75 is configured, for example, by including two or more organic materials (p-type semiconductor materials or n-type semiconductor materials) that function as p-type or n-type semiconductors, respectively. The photoelectric conversion layer 75 has a junction surface (p / n junction surface) between a p-type semiconductor material and an n-type semiconductor material within the layer. The p-type semiconductor functions relatively as an electron donor, and the n-type semiconductor functions relatively as an electron acceptor. The photoelectric conversion layer 75 provides a site where excitons generated upon light absorption separate into electrons and holes. Specifically, the excitons separate into electrons and holes at the interface (p / n junction surface) between the electron donor and electron acceptor.

[0238] In addition to the p-type and n-type semiconductor materials, the photoelectric conversion layer 75 may also contain an organic material, a so-called dye material, that photoelectrically converts light in a predetermined wavelength range while transmitting light in other wavelength ranges. When the photoelectric conversion layer 75 is formed using three types of organic materials, i.e., a p-type semiconductor material, an n-type semiconductor material, and a dye material, the p-type and n-type semiconductor materials are preferably materials that are optically transparent in the visible range (e.g., 450 nm to 800 nm). The thickness of the photoelectric conversion layer 75 is, for example, 50 nm to 500 nm.

[0239] Examples of organic materials that can be used to form the photoelectric conversion layer 75 include quinacridone derivatives, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluoranthene derivatives. The photoelectric conversion layer 75 is formed by combining two or more of the above organic materials. Depending on the combination, the above organic materials function as p-type or n-type semiconductors.

[0240] There are no particular limitations on the organic material that constitutes the photoelectric conversion layer 75. Examples of organic materials that can be used to constitute the photoelectric conversion layer 75 include polymers of phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, and derivatives thereof. Examples of organic materials that can be used to form the photoelectric conversion layer 75 include metal complex dyes, cyanine dyes, merocyanine dyes, phenylxanthene dyes, triphenylmethane dyes, rhodacyanine dyes, xanthene dyes, macrocyclic azaannulene dyes, azulene dyes, naphthoquinone dyes, anthraquinone dyes, condensed polycyclic aromatic compounds such as pyrene, chain compounds formed by condensing aromatic rings or heterocyclic compounds, quinolines having a squarylium group and a croconite methine group as a bonding chain, benzothiazoles, benzoxazoles, and other nitrogen-containing heterocycles, or cyanine-like dyes bonded by a squarylium group and a croconite methine group. Metal complex dyes include dithiol metal complex dyes, metal phthalocyanine dyes, metal porphyrin dyes, and ruthenium complex dyes. Among these, ruthenium complex dyes are particularly preferred, but are not limited to these. However, the photoelectric conversion layer 75 may be made of quantum dots or the like in addition to the organic material.

[0241] In this embodiment, as described above, the insulating portion 75X is formed in the photoelectric conversion layer 75 above the non-opening portion X2, and is configured so that photoelectric conversion does not occur above the non-opening portion X2. This prevents a decrease in external quantum efficiency caused by charge carriers generated in the photoelectric conversion layer 75 above the non-opening portion X2 remaining on the non-opening portion X2. The insulating portion 75X can be formed, for example, by irradiating with a laser or ultraviolet light.

[0242] The upper electrode 76 is made of, for example, a light-transmitting conductive film, similar to the lower electrode 71. The upper electrode 76 is made of, for example, InP doped with Sn. ２ O ３The crystallinity of the ITO film may be high or low (close to amorphous). In addition to the above, the upper electrode 76 may be made of SnO ２ Examples of the material include ATO with Sb added as a dopant and FTO with fluorine added as a dopant. ZnO or a zinc oxide material with a dopant added may also be used. Examples of the ZnO material include AZO with Al added as a dopant, GZO with Ga added, boron zinc oxide with B added, and IZO with In added. IGZO (In-GaZnO4) may also be used with indium and gallium added as dopants. The material for the lower electrode 71 may be CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0243] Furthermore, if optical transparency is not required for the upper electrode 76, a single metal or alloy having a large work function (for example, φ=4.5 eV to 5.5 eV) can be used. Specific examples include Au, Ag, Cr, Ni, Pd, Pt, Fe, iridium (Ir), germanium (Ge), osmium (Os), rhenium (Re), tellurium (Te), and alloys thereof.

[0244] Examples of materials that can be used to form the upper electrode 76 include metals such as Pt, Au, Pd, Cr, Ni, Al, Ag, Ta, W, Cu, Ti, In, Sn, Fe, Co, and Mo, alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials that can be used to form the upper electrode 76 include organic materials (conductive polymers) such as PEDOT / PSS. Alternatively, the above materials can be mixed with a binder (polymer) to form a paste or ink, which can then be cured and used as an electrode.

[0245] The upper electrode 76 can be formed as a single layer or a laminated film made of the above materials. The thickness of the upper electrode 76 is, for example, 20 nm to 200 nm, preferably 30 nm to 150 nm.

[0246] The photoelectric conversion unit 70 may include other layers between the lower electrode 71 and the photoelectric conversion layer 75 and between the photoelectric conversion layer 75 and the upper electrode 76. For example, a hole blocking layer may be provided between the lower electrode 71 and the photoelectric conversion layer 75. The hole blocking layer prevents holes from moving from the lower electrode 71 to the photoelectric conversion layer 75 and efficiently transports electrons, among the charge carriers generated in the photoelectric conversion layer 75, to the lower electrode 71. An electron blocking layer or a work function adjustment layer may be provided between the photoelectric conversion layer 75 and the upper electrode 76. The electron blocking layer prevents electrons from moving from the upper electrode 76 to the photoelectric conversion layer 75 and efficiently transports holes, among the charge carriers generated in the photoelectric conversion layer 75, to the upper electrode 76. The work function adjustment layer has an electron affinity or work function greater than the work function of the upper electrode 76 and improves the electrical connection between the photoelectric conversion layer 75 and the upper electrode 76.

[0247] The photoelectric conversion layer 75 may also have a pin bulk heterostructure in which, for example, a p-type blocking layer, a layer containing p-type and n-type semiconductors (i-layer), and an n-type blocking layer are stacked.

[0248] [Functions and Effects] In the photodetector element 3 of this embodiment, in the photoelectric conversion unit 10 in which the oxide semiconductor layer 73, the protective layer 74, and the photoelectric conversion layer 75 are stacked in this order from the lower electrode 71 side between the lower electrode 71 and the upper electrode 76, an opening X1 having a thickness smaller than that of other regions (non-opening portions X2) and an area equal to or greater than half the area of ​​the storage electrode 71B is formed in the protective layer 74 above the storage electrode 71B constituting the lower electrode 71, and further, an insulating portion 75X is formed in the photoelectric conversion layer 75 above the non-opening portion X2. This makes it possible to prevent a decrease in external quantum efficiency due to charge carriers generated in the photoelectric conversion layer 75 above the non-opening portion X2 remaining on the non-opening portion X2.

[0249] As described above, the photodetector element 3 of this embodiment can improve reliability and sensitivity.

[0250] 6. Modifications (6-1. Modification 19) Fig. 67 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 70A) of a photodetector element according to Modification 19 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 70A is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in Fig. 109, for example.

[0251] In the photoelectric conversion unit 70A of this modification, instead of forming an insulating portion 75X in the photoelectric conversion layer 75 above the non-opening portion X2, the photoelectric conversion layer 75 above the non-opening portion X2 is removed to form an opening 75H. Except for this point, the photoelectric conversion unit 70A has substantially the same configuration as the photoelectric conversion unit 70 of the third embodiment.

[0252] The opening 75H of the photoelectric conversion layer 75 can be formed by using, for example, photolithography or a deposition mask.

[0253] In this manner, in the photoelectric conversion unit 70A of this modification, the photoelectric conversion layer 75 above the non-opening portion X2 is removed to form the opening 75H. As a result, as in the third embodiment, photoelectric conversion above the non-opening portion X2 is prevented, and a decrease in external quantum efficiency due to charge carriers remaining above the non-opening portion X2 can be prevented. Even with this configuration, the photoelectric conversion unit 70A of this modification can obtain the same effects as the photodetector element 3 of the third embodiment.

[0254] 68 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 70B) of a photodetector element according to Modification 20 of the present disclosure. Similar to photodetector element 1 of the first embodiment, a photodetector element including photoelectric conversion unit 70B is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in pixel unit 100A of photodetector device 100 shown in FIG.

[0255] In the photoelectric conversion unit 70B of this modification, instead of forming an insulating portion 75X in the photoelectric conversion layer 75 above the non-opening portion X2, a light-shielding film 77 is provided above the upper electrode 76 so as to cover the region other than the opening portion X1 provided above the storage electrode 71B. Except for this point, the photoelectric conversion unit 70B has substantially the same configuration as the photoelectric conversion unit 70 of the third embodiment.

[0256] The light-shielding film 77 can be formed using, for example, tungsten (W), aluminum (Al), an alloy of Al and copper (Cu), or the like.

[0257] In this manner, in the photoelectric conversion unit 70B of this modification, a light-shielding film 77 is provided so as to cover the region other than the opening X1 provided above the storage electrode 71B. As a result, similar to the third embodiment, photoelectric conversion above the non-opening X2 can be prevented, and a decrease in external quantum efficiency due to charge carriers remaining above the non-opening X2 can be prevented. Therefore, the photoelectric conversion unit 70B of this modification can obtain the same effects as the photodetector element 3 of the third embodiment.

[0258] (6-3. Modification 21) FIG. 69 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 70C) of a photodetector according to Modification 21 of the present disclosure. FIG. 70 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of a photodetector device 100 including the photodetector shown in FIG. 69. Note that FIG. 69 illustrates a cross section corresponding to line IX-IX shown in FIG. 70. Similar to the photodetector device 1 of the first embodiment, the photodetector device including the photoelectric conversion unit 70C is a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG. 109.

[0259] In the photoelectric conversion unit 70C of this modification, instead of forming an insulating portion 75X in the photoelectric conversion layer 75 above the non-opening portion X2, the position of the on-chip lens 52 is adjusted so that light incident on the on-chip lens 52 is focused on the storage electrode 71B. Except for this point, the photoelectric conversion unit 70C has substantially the same configuration as the photoelectric conversion unit 70 of the third embodiment.

[0260] As described above, in the photoelectric conversion unit 70C of this modification, the position of the on-chip lens 52 is adjusted so that light incident on the on-chip lens 52 is focused on the storage electrode 71B. As a result, similar to the third embodiment, photoelectric conversion above the non-opening X2 can be prevented, and a decrease in external quantum efficiency due to charge carriers remaining above the non-opening X2 can be prevented. Even with this configuration, the photoelectric conversion unit 70C of this modification can obtain the same effects as the photodetector element 3 of the third embodiment.

[0261] (6-4. Modification 22) FIG. 71 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 70D) of a photodetector according to Modification 22 of the present disclosure. FIG. 72 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of a photodetector device 100 including the photodetector shown in FIG. 71. Note that FIG. 72 illustrates a cross section corresponding to the X-X line shown in FIG. 71. Similar to the photodetector device 1 of the first embodiment, the photodetector device including the photoelectric conversion unit 70D is a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG. 109, for example.

[0262] In the above-described modification 21, the position of the on-chip lens 52 is adjusted so that light incident on the on-chip lens 52 is focused on the storage electrode 71B, but this is not limiting. The photoelectric conversion unit 70D of this modification is configured so that incident light is focused on the storage electrode 71B by providing a nanophotonics structure 55 above the upper electrode 76. Except for this point, the photoelectric conversion unit 70D has substantially the same configuration as the photoelectric conversion unit 70C of the above-described modification 21.

[0263] The nanophotonics structure 55 is a light-guiding element that utilizes metamaterial (metasurface) technology and is composed of a fine periodic structure including a metasurface photonic crystal. This fine periodic structure has a periodic structure that is equal to or shorter than the wavelength of light detected in the photoelectric conversion layer 75.

[0264] In this manner, in the photoelectric conversion unit 70D of this modification, the nanophotonics structure 55 is provided above the upper electrode 76 so that incident light is focused onto the storage electrode 71B. As a result, even with this configuration, the photoelectric conversion unit 70D of this modification can obtain the same effect as the photoelectric conversion unit 60C of the above modification 21.

[0265] 7. Modifications (7-1. Modification 23) Fig. 73 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 90A) of a photodetector element 5 according to Modification 23 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element 5 including the photoelectric conversion unit 90A is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in Fig. 109, for example.

[0266] The photoelectric conversion unit 90A of this modification further includes a tunnel layer 94A between the protective layer 14 and the photoelectric conversion layer 15. Except for this point, the photoelectric conversion unit 90A has substantially the same configuration as the photoelectric conversion unit 10B of the second modification.

[0267] FIG. 74 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, tunnel layer 94A, photoelectric conversion layer 15, and upper electrode 16 at an opening X1 corresponding to line A-A' in FIG. 73 . FIG. 75 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, protective layer 14, tunnel layer 94A, photoelectric conversion layer 15, and upper electrode 16 at a non-opening X2 corresponding to line B-B' in FIG. 73 . The tunnel layer 94A corresponds to a specific example of a "first layer" according to one embodiment of the present disclosure. Like the protective layer 14, the tunnel layer 94A prevents oxygen from being released from the oxide semiconductor layer 13 and prevents defects from occurring on the surface of the oxide semiconductor layer 13 and in its vicinity. For example, the tunnel layer 94A is provided over the entire surface of the pixel unit 100A.

[0268] The tunnel layer 94A is formed using a metal oxide in which the distance between the metal atom and the oxygen atom (M-O) is short to that of the oxide semiconductor contained in the oxide semiconductor layer 13. Specifically, it is preferable that the difference between the distance between the metal atom and the oxygen atom of the oxide semiconductor contained in the oxide semiconductor layer 13 and the distance between the metal atom and the oxygen atom of the metal oxide used in the tunnel layer 94A is 0.2 Å or less. For example, when the oxide semiconductor layer 13 is made of indium oxide (In ２ O３ ), the tunnel layer 94A is formed by containing yttrium oxide (Y ２ O ３ ) or the like.

[0269] When the tunnel layer 94A is formed using a plurality of types of metal oxides, it is sufficient that the difference between the distance between the metal atom and the oxygen atom of a metal oxide among the plurality of types of metal oxides contained in the tunnel layer 94A, which has the closest distance to the distance between the metal atom and the oxygen atom of the oxide semiconductor contained in the oxide semiconductor layer 13, is 0.2 Å or less. When the tunnel layer 94A is formed using a plurality of types of metal oxides, it is more preferable that the difference between the distance between the metal atom and the oxygen atom of the oxide semiconductor contained in the oxide semiconductor layer 13 and the average distance between the metal atom and the oxygen atom of the plurality of types of metal oxides used in the tunnel layer 94A is 0.2 Å or less.

[0270] The metal oxide used in the tunnel layer 94A and the oxide semiconductor contained in the oxide semiconductor layer 13 preferably have similar crystal systems, and the valences of the respective metal elements are preferably the same. Furthermore, the metal oxide used in the tunnel layer 94A and the oxide semiconductor contained in the oxide semiconductor layer 13 preferably contain the same type of metal element, and the valences of the metal elements commonly contained in the tunnel layer 94A and the oxide semiconductor layer 13 are preferably the same.

[0271] The metal-oxygen bond distance of each of the oxide semiconductor contained in the oxide semiconductor layer 13 and the metal oxide used in the tunnel layer 94A can be analyzed by X-ray diffraction (XRD).

[0272] As described above, in the photoelectric conversion unit 90A of this modification, a tunnel layer 94A using an oxide semiconductor contained in the oxide semiconductor layer 13 and a metal oxide in which the distance between the metal atom and the oxygen atom (M-O) is short is further provided on the protective layer 14. This reduces the lattice mismatch between the oxide semiconductor layer 13 and the tunnel layer 94A, making it possible to reduce the occurrence of defects on the surface of the oxide semiconductor layer 13 and in its vicinity. Therefore, the photoelectric conversion unit 90A of this modification can achieve the same effects as those of the first embodiment.

[0273] 76 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 90B) of a photodetector element according to Modification 24 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element 5 including the photoelectric conversion unit 90B is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0274] The photoelectric conversion unit 90B of this modification further includes a hole blocking layer 94B between the protective layer 14 and the photoelectric conversion layer 15, the hole blocking layer 94B covering the bottom surface of the opening X1 and the top surface and side surface of the non-opening X2 of the protective layer 14. Except for this point, the photoelectric conversion unit 90B has substantially the same configuration as the photoelectric conversion unit 10B of the second modification.

[0275] 77 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, hole blocking layer 94B, photoelectric conversion layer 15, and upper electrode 16 at opening X1 corresponding to line A-A' shown in FIG. 76. The hole blocking layer 94B corresponds to a specific example of a "hole blocking layer" according to an embodiment of the present disclosure. The hole blocking layer 94B is intended to increase the carrier concentration on the surface of the oxide semiconductor layer 13 by accumulating holes in the oxide semiconductor layer 13 above the storage electrode 11B, for example. This reduces the contact resistance between the oxide semiconductor layer 13 and the photoelectric conversion layer 15 and improves conduction. When the vacuum level is defined as a zero reference, and the energy increases (deepens) as the energy moves away from the vacuum level and decreases (shallows) as the energy approaches the vacuum level, the hole blocking layer 94B is configured so that the energy level of the upper end of the valence band of the oxide semiconductor layer 13 is deeper than the energy level of the upper end of the valence band of the hole blocking layer 94B, as shown in FIG. 77 .

[0276] As described above, in the photoelectric conversion unit 90B of this modification, a hole blocking layer 94B having an energy level at the upper end of the valence band shallower than the energy level at the upper end of the valence band of the oxide semiconductor layer 13 is further provided between the protective layer 14 and the photoelectric conversion layer 15. This improves the electrical conduction between the oxide semiconductor layer 13 and the photoelectric conversion layer 15. Therefore, the photoelectric conversion unit 90B of this modification can obtain the same effects as those of the first embodiment.

[0277] 78 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 90C) of a photodetector element according to Modification 25 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element 5 including the photoelectric conversion unit 90C is a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0278] The photoelectric conversion unit 90C of this modification further includes a hole blocking layer 94C between the protective layer 14 and the photoelectric conversion layer 15, the hole blocking layer 94C covering the bottom surface of the opening X1 and the top surface and side surface of the non-opening X2 of the protective layer 14. Except for this point, the photoelectric conversion unit 90C has substantially the same configuration as the photoelectric conversion unit 10B of the second modification.

[0279] FIG. 79 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, hole blocking layer 94C, photoelectric conversion layer 15, and upper electrode 16 at opening X1 corresponding to line A-A' in FIG. 78 . The hole blocking layer 94C corresponds to a specific example of a "hole blocking layer" according to an embodiment of the present disclosure. The hole blocking layer 94C is intended to increase the carrier concentration on the surface of the oxide semiconductor layer 13, for example, by generating a dipole at the interface between the oxide semiconductor layer 13 above the storage electrode 11B and the hole blocking layer 94C. This reduces the contact resistance between the oxide semiconductor layer 13 and the photoelectric conversion layer 15 and improves conduction. Such a hole blocking layer 94C can be formed, for example, using an organic material having a polar group.

[0280] As described above, in the photoelectric conversion unit 90C of this modification, a hole blocking layer 94C is further provided between the protective layer 14 and the photoelectric conversion layer 15, so that a dipole is generated at the interface between the oxide semiconductor layer 13 above the storage electrode 11B and the hole blocking layer 94C. This improves the electrical continuity between the oxide semiconductor layer 13 and the photoelectric conversion layer 15. Therefore, the photoelectric conversion unit 90C of this modification can achieve the same effects as those of the first embodiment.

[0281] 80 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 90D) of a photodetector element according to Modification 26 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element 5 including the photoelectric conversion unit 90D is a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0282] The photoelectric conversion unit 90D of this modification further includes a hole blocking layer 94D between the protective layer 14 and the photoelectric conversion layer 15, the hole blocking layer 94D covering the bottom surface of the opening X1 and the top surface and side surface of the non-opening X2 of the protective layer 14. Except for this point, the photoelectric conversion unit 90D has substantially the same configuration as the photoelectric conversion unit 10B of the second modification.

[0283] FIG. 81 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, hole blocking layer 94D, photoelectric conversion layer 15, and upper electrode 16 at opening X1 corresponding to line A-A' shown in FIG. 80. The hole blocking layer 94D corresponds to a specific example of a "hole blocking layer" according to an embodiment of the present disclosure. The hole blocking layer 94D is intended to form oxygen defects in the oxide semiconductor layer 13 and increase the carrier concentration on the surface of the oxide semiconductor layer 13 by, for example, moving oxygen atoms to the interface between the oxide semiconductor layer 13 above the storage electrode 11B and the hole blocking layer 94D. This reduces the contact resistance between the oxide semiconductor layer 13 and the photoelectric conversion layer 15, improving conduction. The hole blocking layer 94D has an oxygen surface density smaller than that of the oxide semiconductor layer 13, and is made of, for example, yttrium oxide (Y ２ O ３ ), ruthenium oxide (Lu ２ O ３ ), lanthanum oxide (La ２ O ３ The insulating layer can be formed using inorganic materials such as strontium oxide (SrO) and strontium oxide (SrO).

[0284] As described above, in the photoelectric conversion unit 90D of this modification, a hole blocking layer 94D having an oxygen surface density smaller than the oxygen surface density of the oxide semiconductor layer 13 is further provided between the protective layer 14 and the photoelectric conversion layer 15. This improves the electrical conduction between the oxide semiconductor layer 13 and the photoelectric conversion layer 15. Therefore, the photoelectric conversion unit 90D of this modification can obtain the same effects as those of the first embodiment.

[0285] (7-5. Modification 27) FIG. 82 is a schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 90E) of a photodetector according to Modification 27 of the present disclosure. FIG. 83 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of a photodetector device 100 including the photodetector shown in FIG. 82. Note that FIG. 82 illustrates a cross section corresponding to line XIII-XIII shown in FIG. 23. Similar to the photodetector device 1 of the first embodiment, the photodetector device including the photoelectric conversion unit 90E is a photodetector device such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel section 100A of the photodetector device 100 shown in FIG. 109, for example. In the pixel section 100A, as shown in FIG. 83, a pixel unit 5a consisting of four unit pixels P arranged in two rows and two columns serves as a repeating unit, and is repeatedly arranged in an array consisting of row and column directions.

[0286] The photoelectric conversion unit 90E of this modification is configured such that a protective layer 94 having an opening X1 that makes the film thickness smaller than that of other regions is provided above the storage electrode 11B, and the energy level of the upper end of the valence band of this protective layer 94 is deeper than the energy level of the highest occupied molecular orbital of the photoelectric conversion layer 15. Except for this point, the photoelectric conversion unit 90E has substantially the same configuration as the photoelectric conversion unit 10B of the second modification.

[0287] Fig. 84 shows an example of the energy levels of the storage electrode 11B, the insulating layer 12, the oxide semiconductor layer 13, the photoelectric conversion layer 15, and the upper electrode 16 at the opening X1 corresponding to the line A-A' shown in Fig. 82. Fig. 85 shows an example of the energy levels of the shield electrode 11C, the insulating layer 12, the oxide semiconductor layer 13, the protective layer 94, the photoelectric conversion layer 15, and the upper electrode 16 at the non-opening X2 corresponding to the line B-B' shown in Fig. 82.

[0288] As a comparative example, Figure 86 shows an example of the energy levels of the shield electrode 11C, the insulating layer 12, the oxide semiconductor layer 13, the protective layer 94, the photoelectric conversion layer 15, and the upper electrode 16 in the non-opening X2 corresponding to the line B-B' shown in Figure 82. If holes accumulate at the interface between the oxide semiconductor layer 13 and the photoelectric conversion layer 15, for example, as shown in Figure 86, the band of the oxide semiconductor layer 13 bends in the depth direction, which may result in a decrease in the isolation performance between adjacent unit pixels P provided with the shield electrode 11C.

[0289] The protective layer 94 is intended to prevent oxygen from being released from the oxide semiconductor layer 13 and to prevent defects from occurring on the surface of the oxide semiconductor layer 13 and in its vicinity. Similar to the first embodiment, the protective layer 94 has an opening X1 above the storage electrode 11B, which makes the protective layer 94 thinner than other regions. The opening X1 has an area, in plan view, of at least half the area of ​​the storage electrode 11B. The thickness of the protective layer 94 in the non-opening X2 is, for example, 1 nm or more and 100 nm or less. The thickness of the protective layer 94 in the opening X1 is thinner than the thickness of the protective layer 94 in the non-opening X2, and is, for example, 5 nm or less.

[0290] The protective layer 94 can be formed using, for example, an oxide or nitride containing at least one of silicon (Si), germanium (Ge), aluminum (Al), hafnium (Hf), lanthanum (La), strontium (Sr), zirconium (Zr), vanadium (V), tantalum (Ta), titanium (Ti), yttrium (Y), magnesium (Mg), carbon (C), tin (Sn), erbium (Er), ytterbium (Yb), and gadolinium (Gd).

[0291] When the vacuum level is defined as zero, and the energy is defined as increasing (deeper) as the energy is further from the vacuum level and decreasing (shallower) as the energy is closer to the vacuum level, the protective layer 94 is configured to have an energy level at the top of its valence band that is deeper than the energy level of the highest occupied molecular orbital of the photoelectric conversion layer 15. In other words, when the energy level at the top of the valence band of the protective layer 94 is defined as Evn and the energy level of the highest occupied molecular orbital of the photoelectric conversion layer 15 is defined as Evo, Evn > Evo is satisfied. Furthermore, the difference between the energy level at the top of the valence band of the protective layer 94 (Evn) and the energy level of the highest occupied molecular orbital of the photoelectric conversion layer 15 (Evo) is preferably greater than 0.3 eV (Evn - Evo > 0.3), for example. As a result, the protective layer 94 physically separates holes from the interface between the oxide semiconductor layer 13 and the photoelectric conversion layer 15, thereby reducing the impact of holes accumulating on the oxide semiconductor layer 13. Therefore, the deterioration of the isolation performance between the adjacent unit pixels P provided with the shield electrode 11C is suppressed.

[0292] As described above, in the photoelectric conversion unit 90E of this modification, the energy level of the upper end of the valence band of the protective layer 94, which has the opening X1 that makes the film thickness smaller than other regions, is configured to be deeper than the energy level of the highest occupied molecular orbital of the photoelectric conversion layer 15. As a result, as described above, the protective layer 94 physically separates holes from the interface between the oxide semiconductor layer 13 and the photoelectric conversion layer 15, thereby reducing the effect of holes accumulating on the oxide semiconductor layer 13. Therefore, deterioration in isolation performance between adjacent unit pixels P provided with the shield electrode 11C is suppressed, and the photoelectric conversion unit 90E of this modification can further improve reliability compared to the first embodiment.

[0293] 87 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 90F) of a photodetector element according to Modification 28 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 90F is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0294] The photoelectric conversion unit 90F of this modification further includes a hole blocking layer 94E between the protective layer 14 and the photoelectric conversion layer 15, the hole blocking layer 94E covering the bottom surface of the opening X1 and the top surface and side surface of the non-opening X2 of the protective layer 14. Except for this point, the photoelectric conversion unit 90F has substantially the same configuration as the photoelectric conversion unit 10B of the second modification.

[0295] FIG. 88 shows an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, hole blocking layer 94E, photoelectric conversion layer 15, and upper electrode 16 at the opening X1 corresponding to line A-A' in FIG. 87 . FIG. 89 shows an example of energy levels of the shield electrode 11C, insulating layer 12, oxide semiconductor layer 13, protective layer 94, hole blocking layer 94E, photoelectric conversion layer 15, and upper electrode 16 at the non-opening X2 corresponding to line B-B' in FIG. 87 . The hole blocking layer 94E corresponds to a specific example of a "hole blocking layer" according to one embodiment of the present disclosure. The hole blocking layer 94E prevents holes from migrating toward the lower electrode 11. The thickness of the hole blocking layer 94E is, for example, 1 nm or more and 50 nm or less, and preferably, for example, 1 nm or more and 20 nm or less.

[0296] Here, the vacuum level is defined as zero, and the energy is defined as being greater (deeper) as it moves away from the vacuum level, and smaller (shallower) as it moves closer to the vacuum level. The hole blocking layer 94E may be composed of, for example, one or more layers and may be formed using, for example, an inorganic semiconductor. Here, the energy level of the lowest unoccupied molecular orbital of the photoelectric conversion layer 15 is defined as Eco, the energy level of the bottom of the conduction band of the hole blocking layer 94E is defined as Ech, the energy level of the highest occupied molecular orbital of the photoelectric conversion layer 15 is defined as Evo, and the energy level of the top of the valence band of the hole blocking layer 94E is defined as Evh. The hole blocking layer 94E preferably satisfies the following formulas (4) and (5): (Formula 4) Eco - Ech ≦ 0.3 (4) (Formula 5) Evh - Evo > 0.3 (5)

[0297] The hole blocking layer 94E may be composed of, for example, one or more layers and may be formed using, for example, an organic semiconductor. Here, the energy level of the lowest unoccupied molecular orbital of the photoelectric conversion layer 15 is Eco, the energy level of the lowest unoccupied molecular orbital of the hole blocking layer 94E is Ech', the energy level of the highest occupied molecular orbital of the photoelectric conversion layer 15 is Evo, and the energy level of the highest occupied molecular orbital of the hole blocking layer 94E is Evh'. The hole blocking layer 94E preferably satisfies the following formulas (6) and (7): Eco - Ech' ≦ 0.3 (6) Evh' - Evo > 0.3 (7)

[0298] As described above, in the photoelectric conversion unit 90F of this modification, a hole blocking layer 94E that prevents holes from moving toward the lower electrode 11 is further provided between the protective layer 14 and the photoelectric conversion layer 15. As a result, the protective layer 94 physically separates the holes from the interface between the oxide semiconductor layer 13 and the photoelectric conversion layer 15, thereby reducing the effect of holes accumulating on the oxide semiconductor layer 13. Therefore, a decrease in isolation performance between adjacent unit pixels P provided with the shield electrode 11C is suppressed, and the photoelectric conversion unit 90F of this modification can further improve reliability, similar to the photoelectric conversion unit 90E of modification 27.

[0299] 90 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 90G) of a photodetector element according to Modification 29 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 90G is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0300] The photoelectric conversion section 90G of this modification further includes a tunnel layer 94A between the protective layer 14 and the hole blocking layer 94E. Except for this point, the photoelectric conversion section 90G has substantially the same configuration as the photoelectric conversion section 90F of the above-described modification 28.

[0301] Fig. 91 shows an example of the energy levels of the storage electrode 11B, the insulating layer 12, the oxide semiconductor layer 13, the tunnel layer 94A, the hole blocking layer 94E, the photoelectric conversion layer 15, and the upper electrode 16 at the opening X1 corresponding to the line A-A' shown in Fig. 90. Fig. 92 shows an example of the energy levels of the shield electrode 11C, the insulating layer 12, the oxide semiconductor layer 13, the protective layer 94, the tunnel layer 94A, the hole blocking layer 94E, the photoelectric conversion layer 15, and the upper electrode 16 at the non-opening X2 corresponding to the line B-B' shown in Fig. 90.

[0302] Even with this configuration, the photoelectric conversion section 90F of this modification can obtain the same effects as the photoelectric conversion section 90E of the above-described modification 27.

[0303] 93 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 90H) of a photodetector element according to Modification 30 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 90H is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0304] The photoelectric conversion section 90H of this modification further includes an electron transport layer 94F between the protective layer 14 and the hole blocking layer 94E. Except for this point, the photoelectric conversion section 90H has substantially the same configuration as the photoelectric conversion section 90F of the above-described modification 28.

[0305] Fig. 94 shows an example of energy levels of the storage electrode 11B, the insulating layer 12, the oxide semiconductor layer 13, the electron transport layer 94F, the hole blocking layer 94E, the photoelectric conversion layer 15, and the upper electrode 16 at the opening X1 corresponding to the line A-A' shown in Fig. 93. Fig. 95 shows an example of energy levels of the shield electrode 11C, the insulating layer 12, the oxide semiconductor layer 13, the protective layer 94, the electron transport layer 94F, the hole blocking layer 94E, the photoelectric conversion layer 15, and the upper electrode 16 at the non-opening X2 corresponding to the line B-B' shown in Fig. 93.

[0306] The electron transport layer 94F is for collecting charge carriers remaining on the non-opening portion X2, similar to the electron transport layer 64A similar to that of the second embodiment. As described above, the electron transport layer 94F has a higher mobility of charge carriers than the photoelectric conversion layer 65, for example, 10 －３ cm ２ / Vs or more 100cm ２ The electron transport layer 94F has a mobility of 0.1 V or less. The electron transport layer 94F can be formed using, for example, an n-type inorganic semiconductor material. For example, the electron transport layer 94F may be formed using the same material as the hole blocking layer 94E, or may be formed using a different material. The thickness of the electron transport layer 94F is preferably, for example, 0.5 nm or more and 100 nm or less.

[0307] Even with this configuration, the photoelectric conversion section 90H of this modification can obtain the same effects as the photoelectric conversion section 90E of the above-described modification 27.

[0308] 96 is a schematic diagram illustrating an example of a cross-sectional configuration of a main part (photoelectric conversion unit 90I) of a photodetector element according to Modification 31 of the present disclosure. Similar to the photodetector element 1 of the first embodiment, the photodetector element including the photoelectric conversion unit 90I is, for example, a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes, for example, one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 shown in FIG.

[0309] The photoelectric conversion section 90I of this modification is a combination of the above-described modifications 29 and 30, and further includes a tunnel layer 94A and an electron transport layer 94F between the protective layer 14 and the hole blocking layer 94E. Except for this point, the photoelectric conversion section 90I has substantially the same configuration as the photoelectric conversion section 90F of the above-described modification 28.

[0310] Fig. 97 shows an example of energy levels of the storage electrode 11B, the insulating layer 12, the oxide semiconductor layer 13, the tunnel layer 94A, the electron transport layer 94F, the hole blocking layer 94E, the photoelectric conversion layer 15, and the upper electrode 16 at the opening X1 corresponding to the line A-A' shown in Fig. 96. Fig. 98 shows an example of energy levels of the shield electrode 11C, the insulating layer 12, the oxide semiconductor layer 13, the protective layer 94, the tunnel layer 94A, the electron transport layer 94F, the hole blocking layer 94E, the photoelectric conversion layer 15, and the upper electrode 16 at the non-opening X2 corresponding to the line B-B' shown in Fig. 96.

[0311] Note that the stacking order of the tunnel layer 94A and the electron transport layer 94F is not limited to this. FIG. 99 is a schematic diagram illustrating another example of a cross-sectional configuration of a main portion (photoelectric conversion portion 90I) of a photodetector according to Modification Example 31 of the present disclosure. FIG. 100 illustrates an example of energy levels of the storage electrode 11B, insulating layer 12, oxide semiconductor layer 13, tunnel layer 94A, electron transport layer 94F, hole blocking layer 94E, photoelectric conversion layer 15, and upper electrode 16 in an opening X1 corresponding to line A-A' in FIG. 99 . FIG. 101 illustrates an example of energy levels of the shield electrode 11C, insulating layer 12, oxide semiconductor layer 13, protective layer 94, tunnel layer 94A, electron transport layer 94F, hole blocking layer 94E, photoelectric conversion layer 15, and upper electrode 16 in a non-opening X2 corresponding to line B-B' in FIG. 99 .

[0312] Even with this configuration, the photoelectric conversion section 90I of this modification can obtain the same effects as the photoelectric conversion section 90E of the above-described modification 27.

[0313] 8. Other Modifications (8-1. Other Modification 1) FIG. 102A is a schematic diagram illustrating a cross-sectional configuration of a photodetector element 4A according to Other Modification 1 of the present disclosure. FIG. 102B is a schematic diagram illustrating an example of the planar configuration of the photodetector element 4A illustrated in FIG. 102A, where FIG. 102A illustrates a cross section corresponding to line XI-XI illustrated in FIG. 102B. The photodetector element 4A is a stacked photodetector element in which, for example, a photoelectric conversion region 32 and a photoelectric conversion unit 10 are stacked. In a pixel unit 100A of a photodetector device (e.g., photodetector device 100) including this photodetector element 4A, pixel units 1a each consisting of four pixels arranged in two rows and two columns are repeated in an array formed in the row and column directions, as illustrated in FIG. 102B.

[0314] In the photodetector element 4A of this modification, a color filter 56 that selectively transmits red light (R), green light (G), and blue light (B) is provided for each unit pixel P above the photoelectric conversion section 10 (on the light incident surface S1 side). Specifically, in a pixel unit 1a consisting of four pixels arranged in two rows and two columns, two color filters (green filters 56G) that selectively transmit green light (G) are arranged diagonally, and one color filter (red filter 56R and blue filter 56B) that selectively transmit red light (R) and blue light (B) is arranged on each diagonal that is perpendicular to the pixel unit 1a. In the unit pixels (Pr, Pg, Pb) provided with the color filters 56R, 56G, and 56B, the photoelectric conversion section 10 detects light of the corresponding color, for example. That is, in the pixel section 100A, pixels (Pr, Pg, Pb) that detect red light (R), green light (G), and blue light (B) are arranged in a Bayer pattern.

[0315] The photoelectric conversion unit 10 absorbs light corresponding to some or all of the wavelengths in the visible light region, for example, between 400 nm and 750 nm, to generate excitons (electron-hole pairs), and includes a lower electrode 11, an insulating layer 12, an oxide semiconductor layer 13, a protective layer 14, a photoelectric conversion layer 15, and an upper electrode 16 stacked in this order. As in the first embodiment, the lower electrode 11 has, for example, a readout electrode 11A and a storage electrode 11B that are independent of each other, and the readout electrode 11A is shared by, for example, four pixels. The oxide semiconductor layer 13 may be omitted. The protective layer 14 has, for example, an opening X1 above the readout electrode 81A and the storage electrode 81B.

[0316] The photoelectric conversion region 32 detects, for example, an infrared light region of 750 nm or more and 1300 nm or less.

[0317] In the photodetector element 4A, light in the visible light region (red light (R), green light (G), and blue light (B)) that passes through the color filters 56 is absorbed by the photoelectric conversion units 10 of the unit pixels (Pr, Pg, Pb) in which the color filters 56R, 56G, and 56B are provided, respectively. Other light, for example, light in the infrared region (e.g., 750 nm or more and 1000 nm or less) (infrared light (IR)), passes through the photoelectric conversion units 10. The infrared light (IR) that passes through the photoelectric conversion units 10 is detected in the photoelectric conversion regions 32 of the unit pixels Pr, Pg, and Pb, and signal charges corresponding to the infrared light (IR) are generated. In other words, a photodetector device 100 including the photodetector element 4A can simultaneously generate both visible light images and infrared light images.

[0318] Furthermore, the photodetector device 100 including the photodetector element 4A can acquire a visible light image and an infrared light image at the same position in the XZ in-plane direction, thereby enabling high integration in the XZ in-plane direction.

[0319] (8-2. Other Modification 2) FIG. 103A is a schematic diagram illustrating a cross-sectional configuration of a photodetector 4B according to another modification 2 of the present disclosure. FIG. 103B is a schematic diagram illustrating an example of the planar configuration of the photodetector 4B illustrated in FIG. 103A, and FIG. 103A illustrates a cross section corresponding to line XII-XII illustrated in FIG. 103B. In the above modification 1, an example was shown in which the color filter 56 was provided above the photoelectric conversion unit 10 (on the light incident surface S1 side). However, the color filter 56 may be provided, for example, between the photoelectric conversion region 32 and the photoelectric conversion unit 10, as illustrated in FIG. 103A. Except for this point, the photodetector 4B has substantially the same configuration as the photodetector 4A according to the above modification 1.

[0320] In the photodetector element 4B, for example, the color filter 56 has a configuration in which a color filter (red filter 56R) that selectively transmits at least red light (R) and a color filter (blue filter 56B) that selectively transmits at least blue light (B) are arranged diagonally opposite each other within the pixel unit 1a. The photoelectric conversion layer 15 of the photoelectric conversion unit 10 is configured to selectively absorb light having a wavelength corresponding to green light (G), for example. The photoelectric conversion region 32R selectively absorbs light having a wavelength corresponding to red light (R), and the photoelectric conversion region 32B selectively absorbs light having a wavelength corresponding to blue light (B). This makes it possible to obtain signals corresponding to red light (R), green light (G), or blue light (B) in the photoelectric conversion regions 32 (photoelectric conversion regions 32R, 32B) arranged below the photoelectric conversion unit 10 and the red filter 56R and blue filter 55B, respectively. In the photodetector element 4B of this modified example, the area of ​​the photoelectric conversion portion for each of RGB can be enlarged compared to a photodetector element having a general Bayer array, and therefore the S / N ratio can be improved.

[0321] 104 is a schematic diagram illustrating a cross-sectional configuration of a photodetector 4C according to another modification 3 of the present disclosure. Similar to the photodetector 1 of the first embodiment, the photodetector 4C is a photodetector such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras. The photodetector 4C of this modification has two photoelectric conversion units 10, 80 and one photoelectric conversion region 32 stacked in the vertical direction.

[0322] The photoelectric conversion units 10 and 80 and the photoelectric conversion region 32 selectively detect light in different wavelength ranges and perform photoelectric conversion. For example, the photoelectric conversion unit 10 acquires a green (G) color signal. For example, the photoelectric conversion unit 80 acquires a blue (B) color signal. For example, the photoelectric conversion region 32 acquires a red (R) color signal. This makes it possible for the photodetector 4C to acquire multiple types of color signals in one pixel without using color filters.

[0323] The photoelectric conversion unit 80 has a similar configuration to the photoelectric conversion unit 10. Specifically, like the photoelectric conversion unit 10, the photoelectric conversion unit 80 includes a lower electrode 81, a photoelectric conversion layer 85, and an upper electrode 86 stacked in this order. The lower electrode 61 includes multiple electrodes (e.g., a readout electrode 81A and a storage electrode 81B), and an insulating layer 82, an oxide semiconductor layer 83, and a protective layer 84 stacked in this order between the lower electrode 81 and the photoelectric conversion layer 85. Of the lower electrode 81, the readout electrode 81A is electrically connected to the oxide semiconductor layer 83 through an opening 82H provided in the insulating layer 82. Note that the oxide semiconductor layer 83 may be omitted. Like the protective layer 14, the protective layer 84 includes openings X1 above the readout electrode 81A and the storage electrode 81B, for example.

[0324] A through electrode 87 is connected to the readout electrode 81A, which penetrates the interlayer insulating layer 88 and the photoelectric conversion unit 10 and is electrically connected to the readout electrode 11A of the photoelectric conversion unit 10. Furthermore, the readout electrode 81A is electrically connected to a floating diffusion FD provided in the semiconductor substrate 30 via the through electrodes 34 and 87, and can temporarily store charge carriers generated in the photoelectric conversion layer 85. Furthermore, the readout electrode 81A is electrically connected to an amplifier transistor AMP and the like provided in the semiconductor substrate 30 via the through electrodes 34 and 87.

[0325] (8-4. Other Modifications 4 to 7) FIG. 105 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector element (photodetector element 4D) according to Other Modification 4 of the present disclosure. FIG. 106A is a schematic diagram illustrating another example of a cross-sectional configuration of a photodetector element (photodetector element 4E) according to Other Modification 5 of the present disclosure. FIG. 106B is a schematic diagram illustrating an example of a planar configuration of the photodetector element 4E shown in FIG. 106A. FIG. 107A is a schematic diagram illustrating another example of a cross-sectional configuration of a photodetector element (photodetector element 4F) according to Other Modification 6 of the present disclosure. FIG. 107B is a schematic diagram illustrating an example of a planar configuration of the photodetector element 4F shown in FIG. 107A. FIG. 108 is a schematic diagram illustrating another example of a cross-sectional configuration of a photodetector element (photodetector element 4G) according to Other Modification 7 of the present disclosure. Like the photodetector element 1 of the first embodiment, the photodetector elements 4D to 4G are used as imaging elements such as CMOS image sensors used in electronic devices such as digital still cameras, video cameras, etc. The photodetector elements 4D to 4G of this modification differ from the photodetector elements of the first embodiment in that the lower electrode 11 is composed of one electrode for each unit pixel P.

[0326] Similar to the photodetector element 1, the photodetector element 4D has one photoelectric conversion unit 10 and two photoelectric conversion regions 32B and 32R stacked in the vertical direction for each unit pixel P. The photoelectric conversion unit 10 is provided on the back surface (first surface 30A) side of the semiconductor substrate 30. The photoelectric conversion regions 32B and 32R are embedded in the semiconductor substrate 30 and stacked in the thickness direction of the semiconductor substrate 30.

[0327] The photodetector element 4G of this modified example has the same configuration as the photodetector element 1, except that, as described above, the lower electrodes 11, 81 of the photoelectric conversion units 10, 80 consist of a single electrode, and no insulating layers 12, 82 are provided between the lower electrodes 11, 81 and the oxide semiconductor layers 13, 83.

[0328] The configuration of the photoelectric conversion units 10 and 80 is not limited to the photodetector element 1 of the first embodiment described above, and the same effects as those of each embodiment can be obtained even if the configuration of the photoelectric conversion units 60 and 70 of the second or third embodiment described above is used.

[0329] 9. Fourth Embodiment Fig. 116 is a schematic diagram illustrating an example of a cross-sectional configuration of a photodetector element (photodetector element 6) according to a fourth embodiment of the present disclosure. Fig. 117 is a schematic diagram illustrating an example of a planar configuration of a photodetector device 100 including the photodetector element 6 illustrated in Fig. 116. The photodetector element 6 constitutes one pixel (unit pixel P) repeatedly arranged in an array in, for example, a pixel section 100A of a photodetector device 100 illustrated in Fig. 109 , such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras. In the pixel section 100A, the unit pixels P are repeatedly arranged in an array consisting of row and column directions, as illustrated in Fig. 117, for example.

[0330] The photodetector element 6 of this embodiment has a protective layer 97, a charge transport layer 98, and a photoelectric conversion layer 95 stacked in this order from the lower electrode 91 side between a lower electrode 91 and an upper electrode 96. The lower electrode 91 is provided for each unit pixel P. The protective layer 97 has an opening 97H1 for each unit pixel P. The charge transport layer 98 is provided, for example, across a plurality of unit pixels P, and is separated from the lower electrode 91 by a step portion between the lower electrode 91 and the protective layer 97, which is defined by the opening 97H1 in the protective layer 97.

[0331] Here, the photoelectric conversion layer 95 corresponds to a specific example of a "photoelectric conversion layer" according to one embodiment of the present disclosure. The lower electrode 91 corresponds to a specific example of a "first electrode" according to one embodiment of the present disclosure. The upper electrode 96 corresponds to a specific example of a "second electrode" according to one embodiment of the present disclosure. The protective layer 97 corresponds to a specific example of a "protective layer" according to one embodiment of the present disclosure. The opening 97H1 corresponds to a specific example of an "opening" according to one embodiment of the present disclosure. The outside of the opening 97H1 corresponds to a specific example of a "non-opening" according to one embodiment of the present disclosure. The charge transport layer 98 corresponds to a specific example of a "charge transport layer" according to one embodiment of the present disclosure.

[0332] [Configuration of photodetector element] The photodetector element 6 is a so-called vertical spectroscopic type in which one photoelectric conversion unit 90J that selectively detects light in different wavelength ranges and performs photoelectric conversion, and two photoelectric conversion regions 32B and 32R are stacked vertically.

[0333] In the light-detecting element 6, the photoelectric conversion unit 90J is provided on the back surface (first surface 30S1) side of the semiconductor substrate 30, similar to the first embodiment. The photoelectric conversion regions 32B, 32R are embedded in the semiconductor substrate 30 and stacked in the thickness direction of the semiconductor substrate 30, similar to the first embodiment.

[0334] In FIG. 116, the first surface 30S1 side of the semiconductor substrate 30 is represented as the light incident surface S1, and the second surface 30S2 side is represented as the wiring layer side S2.

[0335] Fig. 118 is a plan view showing an example of the configuration of a photodetector element 6 in which a plurality of photoelectric conversion units (e.g., the photoelectric conversion regions 32B, 32R and the photoelectric conversion unit 90J) to which the technology according to the present disclosure can be applied are stacked. That is, Fig. 118 shows, for example, an example of the planar configuration of a unit pixel P that constitutes the pixel unit 100A shown in Fig. 117.

[0336] The unit pixel P has a photoelectric conversion region 1100 in which a red photoelectric conversion unit (photoelectric conversion region 32R in FIG. 116 ), a blue photoelectric conversion unit (photoelectric conversion region 32B in FIG. 116 ), and a green photoelectric conversion unit (photoelectric conversion unit 90J in FIG. 116 ) (none of which are shown in FIG. 118 ) that photoelectrically convert light of the respective wavelengths of R (Red), G (Green), and B (Blue) are stacked in three layers, for example, in the order of the green photoelectric conversion unit, the blue photoelectric conversion unit, and the red photoelectric conversion unit from the light receiving surface (light incident surface S1 in FIG. 116 ) side. Furthermore, the unit pixel P has Tr groups 1110, 1120, and 1130 as charge readout units that read out charges corresponding to light of the respective wavelengths of RGB from the red photoelectric conversion unit, the green photoelectric conversion unit, and the blue photoelectric conversion unit. In the photodetector element 1, in one unit pixel P, the light is split in the vertical direction, i.e., split into RGB light in each layer serving as a red photoelectric conversion unit, a green photoelectric conversion unit, and a blue photoelectric conversion unit stacked in the photoelectric conversion region 1100.

[0337] Tr group 1110, Tr group 1120, and Tr group 1130 are formed around the photoelectric conversion region 1100. Tr group 1110 outputs signal charges corresponding to R light generated and accumulated in the red photoelectric conversion unit as pixel signals. Tr group 1110 is composed of a transfer Tr (MOS FET) 1111, a reset Tr 1112, an amplifier Tr 1113, and a selection Tr 1114. Tr group 1120 outputs signal charges corresponding to B light generated and accumulated in the blue photoelectric conversion unit as pixel signals. Tr group 1120 is composed of a transfer Tr 1121, a reset Tr 1122, an amplifier Tr 1123, and a selection Tr 1124. Tr group 1130 outputs signal charges corresponding to G light generated and accumulated in the green photoelectric conversion unit as pixel signals. The Tr group 1130 is composed of a transfer Tr 1131 , a reset Tr 1132 , an amplifier Tr 1133 and a selection Tr 1134 .

[0338] Transfer Tr 1111 is composed of a gate G, a source / drain region S / D, and an FD (floating diffusion) 1115 (a source / drain region that serves as the gate G). Transfer Tr 1121 is composed of a gate G, a source / drain region S / D, and an FD2125. Transfer Tr 1131 is composed of a gate G, a green photoelectric conversion section (a source / drain region S / D connected thereto) in the photoelectric conversion region 1100, and an FD2135. The source / drain region of transfer Tr 1111 is connected to the red photoelectric conversion section in the photoelectric conversion region 1100, and the source / drain region S / D of transfer Tr 1121 is connected to the blue photoelectric conversion section in the photoelectric conversion region 1100.

[0339] Each of the reset Tr 1112, 1132, and 1122, the amplification Tr 1113, 1133, and 1123, and the selection Tr 1114, 1134, and 1124 is composed of a gate G and a pair of source / drain regions S / D arranged so as to sandwich the gate G therebetween.

[0340] The FDs 1115, 1135, and 1125 are connected to the source / drain regions S / D that form the sources of the reset Trs 1112, 1132, and 1122, respectively, and are also connected to the gates G of the amplifier Trs 1113, 1133, and 1123, respectively. A power supply Vdd is connected to the source / drain regions S / D that are common to the reset Tr 1112 and the amplifier Tr 1113, the reset Tr 1132 and the amplifier Tr 1133, and the reset Tr 1122 and the amplifier Tr 1123. A VSL (vertical signal line) is connected to the source / drain regions S / D that form the sources of the selection Trs 1114, 1134, and 1124.

[0341] The photoelectric conversion unit 90J of this embodiment is formed by stacking a lower electrode 91, a protective layer 97, a charge transport layer 98, a photoelectric conversion layer 95, and an upper electrode 96 in this order from the semiconductor substrate 30 side. The photoelectric conversion layer 95 is configured to include, for example, a p-type semiconductor and an n-type semiconductor, and has a bulk heterojunction structure within the layer. The bulk heterojunction structure is a p / n junction surface formed by mixing a p-type semiconductor and an n-type semiconductor.

[0342] The lower electrode 91 is formed separately for each unit pixel P, for example. The lower electrode 91 is made of, for example, a light-transmitting conductive film. The lower electrode 91 preferably has a work function of, for example, 4.0 eV or more and 5.5 eV or less. The constituent material of such a lower electrode 91 is, for example, InP doped with tin (Sn) as a dopant. ２ O ３ The ITO film may have high or low crystallinity (close to amorphous). In addition to the above, the lower electrode 91 may also be made of a material such as tin oxide (SnO ２)-based materials, for example, ATO with antimony (Sb) added as a dopant, and FTO with fluorine (F) added as a dopant may be used. Zinc oxide (ZnO) or a zinc oxide-based material with a dopant added thereto may also be used. Examples of ZnO-based materials include aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, boron zinc oxide with boron (B) added, and indium zinc oxide (IZO) with indium (In) added. Furthermore, zinc oxide with indium and gallium added as dopants (IGZO, In-GaZnO ４ The lower electrode 91 may be made of CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0343] If the lower electrode 91 does not need to be optically transparent (for example, if light is incident from the upper electrode 96 side and the photoelectric conversion regions 32R and 32B are not provided below the storage electrode 11B), a single metal or alloy having a small work function (for example, φ=3.5 eV to 4.5 eV) can be used. Specific examples include alkali metals (for example, lithium (Li), sodium (Na), and potassium (K)) and their fluorides or oxides, and alkaline earth metals (for example, magnesium (Mg) and calcium (Ca)) and their fluorides or oxides. Other examples include rare earth metals such as aluminum (Al), Al—Si—Cu alloys, zinc (Zn), tin (Sn), thallium (Tl), Na—K alloys, Al—Li alloys, Mg—Ag alloys, In, and ytterbium (Yb), or alloys thereof.

[0344] Examples of materials that can be used to form the lower electrode 91 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), and molybdenum (Mo), alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials that can be used to form the lower electrode 91 include organic materials (conductive polymers) such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (PEDOT / PSS). Alternatively, the above materials can be mixed with a binder (polymer) to form a paste or ink, which can then be cured and used as an electrode.

[0345] The lower electrode 91 can be formed as a single layer or a laminated film made of the above materials. The film thickness of the lower electrode 91 in the lamination direction (hereinafter simply referred to as thickness) is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0346] The protective layer 97 is intended to reduce the occurrence of charge leakage at the end of the lower electrode 91 formed separately for each unit pixel P. The protective layer 97 is provided, for example, to fill the gaps between the lower electrodes 91 formed separately for each unit pixel P and to extend over the outer edges of the lower electrodes 91. In other words, as shown in FIG. 117 , for example, the protective layer 97 has an opening 97H1 formed for each unit pixel P, and is extended in, for example, a grid pattern in the pixel section 100A.

[0347] The protective layer 97 can be formed using an insulating material such as an oxide or nitride containing at least one of silicon (Si), germanium (Ge), aluminum (Al), hafnium (Hf), lanthanum (La), strontium (Sr), zirconium (Zr), vanadium (V), tantalum (Ta), titanium (Ti), yttrium (Y), magnesium (Mg), carbon (C), tin (Sn), erbium (Er), ytterbium (Yb), and gadolinium (Gd).

[0348] The thickness of the protective layer 97 is greater than that of the lower electrode 91. Specifically, the thickness of the protective layer 97 is preferably such that, for example, the height (h) from the upper surface of the lower electrode 91 exposed in the opening 97H1 to the upper surface of the protective layer 97 is at least five times the thickness of the charge transport layer 98. For example, when the thickness of the charge transport layer 98 is 10 nm, the height (h) is 5 nm or more and 200 nm or less.

[0349] 119A to 119E are schematic diagrams illustrating an example of the cross-sectional shape of the protective layer 97 corresponding to, for example, line XIII-XIII shown in FIG. 117. The cross-sectional shape of the protective layer 97 between adjacent unit pixels P is, for example, as shown in FIG. 119A, an inverted tapered shape in which the width of the upper surface 97S1 is wider than the width of the lower surface 97S2 and the angle (θ) between the lower surface 97S2 and the side surface 97S3 is an obtuse angle. Alternatively, the cross-sectional shape of the protective layer 97 between adjacent unit pixels P may be, for example, an eave shape in which a triangle wider than the rectangle is stacked on top of the rectangle, as shown in FIG. 119B, or a multi-tiered eave shape in which multiple eave shapes shown in FIG. 119B are stacked on top of each other, as shown in FIG. 119C. Alternatively, the cross-sectional shape of the protective layer 97 between adjacent unit pixels P may be, for example, an edge-gouged type in which the side surface 97S3 on the lower surface 97S2 side is gouged out as shown in FIG. 119D, or an upper-gouged type in which, for example, a trapezoidal groove 97H2 is formed in the surface on the upper surface 97S1 side of the protective layer 97 as shown in FIG. 119E.

[0350] The canopy-shaped protective layer 97 shown in FIG. 119B can be formed, for example, as follows.

[0351] 120A to 120E show the process sequence of a method for manufacturing the overhanging protective layer 97. First, as shown in Fig. 120A, for example, an oxide film 97A, a nitride film 97B, and an oxide film 97C are formed in this order as the protective layer 97 on the lower electrode 91. Next, as shown in Fig. 120A, a resist film 301 is patterned on the oxide film 97C.

[0352] Next, as shown in FIG. 120B, the oxide film 97C exposed from the resist film 301 is processed by etching using the resist film 301 as a mask to form an opening 971H at the bottom of which the nitride film 97B is exposed, and then the resist film 301 is removed.

[0353] Next, as shown in FIG. 120C, the inner corners of the opening 971H of the oxide film 97C are rounded off by, for example, argon sputtering.

[0354] Subsequently, as shown in FIG. 120D, a resist film 302 is patterned so as to cover the oxide film 97C and to expose a part of the nitride film 97B inside the opening 971H.

[0355] 120E, the nitride film 97B exposed from the resist film 302 is processed by etching using the resist film 302 as a mask, and the etching is stopped midway through the oxide film 97A underneath so as not to expose the lower electrode 91. At this time, it is preferable that the thickness of the etched oxide film 97A is about 20 nm.

[0356] 120F, the oxide film 97A remaining on the lower electrode 91 is removed by etch-back to expose the lower electrode 91. This etch-back also reduces the thickness of the oxide film 97C, and causes the side surface of the nitride film 97B in the opening 971H to recede in the in-plane direction.

[0357] 120G, the side surfaces of the nitride film 97B are further recessed by, for example, chemical dry etching (CDE) which allows isotropic etching, thereby forming eaves-like steps on the side surfaces of the protective layer 97.

[0358] The charge transport layer 98 is for facilitating the movement of charges (e.g., electrons) generated in the photoelectric conversion layer 95 to the lower electrode 91. Similar to the electron transport layer 64A in the second embodiment, the charge transport layer 98 has a higher mobility of charge carriers than the photoelectric conversion layer 95, for example, 10 －３ cm ２ / Vs or more 100cm ２ / Vs or less.

[0359] The charge transport layer 98 can be formed using, for example, an n-type inorganic semiconductor material. Specific examples of materials that can be used to form the charge transport layer 98 include IGZO (In—Ga—Zn—O-based oxide semiconductor), zinc oxide (ZnO), and ITO. From the viewpoint of electron transport properties, the thickness of the charge transport layer 98 is preferably, for example, 0.5 nm or more and 100 nm or less.

[0360] In the present embodiment, the charge transport layer 98 is provided across a plurality of unit pixels P as described above, and is divided by a step portion between the lower electrode 81 and the protective layer 97, which is formed by an opening 97H1 in the protective layer 97. Alternatively, as shown in FIG. 119E , for example, when the protective layer 97 between adjacent unit pixels P has an upper-hollowed cross-sectional shape, the charge transport layer 98 is divided by a step portion of a groove 97H2 provided in an upper surface 97S1 of the protective layer 97. In other words, the charge transport layer 98 is provided in the form of a plurality of islands divided, for example, somewhere between the photoelectric conversion layer 95 and the lower electrode 81 and somewhere between the photoelectric conversion layer 95 and the protective layer 97.

[0361] The photoelectric conversion layer 95 converts light energy into electrical energy. The photoelectric conversion layer 95 is configured, for example, to contain two or more organic materials (p-type semiconductor materials or n-type semiconductor materials) that function as p-type or n-type semiconductors, respectively. The photoelectric conversion layer 95 has a junction surface (p / n junction surface) between a p-type semiconductor material and an n-type semiconductor material within the layer. The p-type semiconductor functions relatively as an electron donor, and the n-type semiconductor functions relatively as an electron acceptor. The photoelectric conversion layer 95 provides a site where excitons generated upon light absorption separate into electrons and holes. Specifically, the excitons separate into electrons and holes at the interface (p / n junction surface) between the electron donor and electron acceptor.

[0362] In addition to the p-type and n-type semiconductor materials, the photoelectric conversion layer 95 may also contain an organic material, a so-called dye material, that photoelectrically converts light in a predetermined wavelength range while transmitting light in other wavelength ranges. When the photoelectric conversion layer 95 is formed using three types of organic materials, i.e., a p-type semiconductor material, an n-type semiconductor material, and a dye material, the p-type and n-type semiconductor materials are preferably materials that are optically transparent in the visible range (e.g., 450 nm to 800 nm). The thickness of the photoelectric conversion layer 95 is, for example, 50 nm to 500 nm.

[0363] Examples of organic materials that can be used to form the photoelectric conversion layer 95 include quinacridone derivatives, naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, and fluoranthene derivatives. The photoelectric conversion layer 95 is formed by combining two or more of the above organic materials. Depending on the combination, the above organic materials function as p-type or n-type semiconductors.

[0364] There are no particular limitations on the organic material that constitutes the photoelectric conversion layer 95. Examples of organic materials that can be used to constitute the photoelectric conversion layer 95 include polymers of phenylene vinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, and derivatives thereof. Examples of organic materials that can be used to form the photoelectric conversion layer 95 include metal complex dyes, cyanine dyes, merocyanine dyes, phenylxanthene dyes, triphenylmethane dyes, rhodacyanine dyes, xanthene dyes, macrocyclic azaannulene dyes, azulene dyes, naphthoquinone dyes, anthraquinone dyes, condensed polycyclic aromatic compounds such as pyrene, chain compounds formed by condensing aromatic rings or heterocyclic compounds, quinoline having a squarylium group and a croconite methine group as a bonding chain, benzothiazole, benzoxazole, and other nitrogen-containing heterocycles, or cyanine-like dyes bonded by a squarylium group and a croconite methine group. Metal complex dyes include dithiol metal complex dyes, metal phthalocyanine dyes, metal porphyrin dyes, and ruthenium complex dyes. Among these, ruthenium complex dyes are particularly preferred, but are not limited to these. However, the photoelectric conversion layer 95 may be made of quantum dots or the like in addition to the organic material.

[0365] The upper electrode 96 is made of, for example, a light-transmitting conductive film, similar to the lower electrode 91. The upper electrode 96 is made of, for example, InP doped with Sn. ２ O ３ The crystallinity of the ITO film may be high or low (close to amorphous). In addition to the above, the upper electrode 96 may be made of SnO ２Examples of the material include ATO with Sb added as a dopant and FTO with fluorine added as a dopant. ZnO or a zinc oxide material with a dopant added may also be used. Examples of the ZnO material include AZO with Al added as a dopant, GZO with Ga added, boron zinc oxide with B added, and IZO with In added. IGZO (In-GaZnO4) may also be used with indium and gallium added as dopants. The material for the upper electrode 96 may be CuI, InSbO ４ , ZnMgO, CuInO ２ , MgIN ２ O ４ , CdO, ZnSnO ３ or TiO ２ Alternatively, spinel oxides or YbFe ２ O ４ Oxides having such a structure may also be used.

[0366] Furthermore, if optical transparency is not required for the upper electrode 96, a single metal or alloy having a large work function (for example, φ=4.5 eV to 5.5 eV) can be used. Specific examples include Au, Ag, Cr, Ni, Pd, Pt, Fe, iridium (Ir), germanium (Ge), osmium (Os), rhenium (Re), tellurium (Te), and alloys thereof.

[0367] Examples of materials that can be used to form the upper electrode 96 include metals such as Pt, Au, Pd, Cr, Ni, Al, Ag, Ta, W, Cu, Ti, In, Sn, Fe, Co, and Mo, alloys containing these metal elements, conductive particles made of these metals, conductive particles of alloys containing these metals, polysilicon containing impurities, carbon-based materials, oxide semiconductors, carbon nanotubes, and graphene. Other examples of materials that can be used to form the upper electrode 96 include organic materials (conductive polymers) such as PEDOT / PSS. Alternatively, the above materials can be mixed with a binder (polymer) to form a paste or ink, which can then be hardened and used as an electrode.

[0368] The upper electrode 96 can be formed as a single layer or a laminated film made of the above materials. The thickness of the upper electrode 96 is, for example, 20 nm to 200 nm, and preferably 30 nm to 150 nm.

[0369] The photoelectric conversion unit 90J may have other layers between the lower electrode 91 and the photoelectric conversion layer 95 and between the photoelectric conversion layer 95 and the upper electrode 96. For example, a hole blocking layer may be provided between the lower electrode 91 and the photoelectric conversion layer 95. The hole blocking layer prevents holes from moving from the lower electrode 91 to the photoelectric conversion layer 95 and efficiently transports electrons, among the charge carriers generated in the photoelectric conversion layer 95, to the lower electrode 91. An electron blocking layer or a work function adjustment layer may be provided between the photoelectric conversion layer 95 and the upper electrode 96. The electron blocking layer prevents electrons from moving from the upper electrode 96 to the photoelectric conversion layer 95 and efficiently transports holes, among the charge carriers generated in the photoelectric conversion layer 95, to the upper electrode 96. The work function adjustment layer has an electron affinity or work function greater than the work function of the upper electrode 96 and improves the electrical connection between the photoelectric conversion layer 95 and the upper electrode 96.

[0370] 1 and 3 show an example in which the insulating layer 12, the oxide semiconductor layer 13, the photoelectric conversion layer 95, and the upper electrode 96 are formed separately for each unit pixel P, but the oxide semiconductor layer 13, the photoelectric conversion layer 95, and the upper electrode 96 may be formed continuously for multiple unit pixels P, for example.

[0371] [Functions and Effects] In the photodetector element 6 of this embodiment, the charge transport layer 98 provided on the lower electrode 91 side of the photoelectric conversion layer 95 is divided, for example, at a step portion between the lower electrode 81 and the protective layer 97, which is formed by the opening 97H1 in the protective layer 97. This blocks the movement of charges between adjacent unit pixels P where a weak electric field is applied to the photoelectric conversion layer 95.

[0372] As described above, in the photodetector element 6 of this embodiment, it is possible to reduce crosstalk between adjacent unit pixels P.

[0373] 10. Modifications (10-1. Modification 33) FIG. 121 is a schematic diagram illustrating an example of a cross-sectional configuration of a main portion (photoelectric conversion unit 90K) of a photodetector element 6A according to Modification 33 of the present disclosure. FIG. 122 is a schematic diagram illustrating an example of a planar layout of a pixel configuration of a photodetector device 100 including the photodetector element illustrated in FIG. 120. Note that FIG. 120 illustrates a cross section corresponding to line XIV-XIV illustrated in FIG. 121. Similar to the photodetector element 1 of the fourth embodiment, the photodetector element including the photoelectric conversion unit 90K is a photodetector element such as a CMOS image sensor used in electronic devices such as digital still cameras and video cameras, and constitutes one pixel (unit pixel P) repeatedly arranged in an array in the pixel unit 100A of the photodetector device 100 illustrated in FIG. 109, for example. In the pixel section 100A, as shown in FIG. 122, a pixel unit 1a consisting of four unit pixels P arranged in, for example, two rows and two columns is a repeating unit, and is repeatedly arranged in an array consisting of row and column directions.

[0374] In the fourth embodiment, an example in which a lower electrode 91 is provided for each unit pixel P has been described, but the present invention is not limited to this. In the photoelectric conversion unit 90K of this modification, an oxide semiconductor layer 93, a protective layer 97, a charge transport layer 98, and a photoelectric conversion layer 95 are stacked in this order from the lower electrode 91 side between the lower electrode 91 and the upper electrode 96, and the lower electrode 91 is composed of a readout electrode 91A, a storage electrode 91B, a shield electrode 91C, and a transfer electrode 91D, similar to the first modification and the like. Except for this point, the photoelectric conversion unit 90K has substantially the same configuration as the photoelectric conversion unit 90J of the fourth embodiment.

[0375] Also, although not shown in Figure 116, a void 95X, such as that shown in Figure 121, may be formed in the photoelectric conversion layer 95 near the lower surface 97S2 of the protective layer 97 having a cross-sectional shape as shown in Figures 119A to 119E.

[0376] Even with this configuration, the photodetector element 6A of this modification can achieve the same effects as the photodetector element 6 of the fourth embodiment. Furthermore, in this modification, the protective layer 97, like the first embodiment, can prevent oxygen from being released from the oxide semiconductor layer 93 and prevent defects from occurring on the surface of the oxide semiconductor layer 93 and in the vicinity thereof, thereby improving reliability.

[0377] 11. Application Examples Application Example 1 FIG. 109 shows an example of the overall configuration of a photodetector (photodetector 100) including the photodetector element (for example, photodetector element 1) shown in FIG. 1 and the like.

[0378] The photodetector 100 is, for example, a CMOS image sensor that captures incident light (image light) from a subject via an optical lens system (not shown), converts the amount of incident light imaged on an imaging surface into an electrical signal for each pixel, and outputs the signal as a pixel signal. The photodetector 100 has a pixel section 100A as an imaging area on a semiconductor substrate 30, and also has, in a peripheral region of the pixel section 100A, for example, a vertical drive circuit 111, a column signal processing circuit 112, a horizontal drive circuit 113, an output circuit 114, a control circuit 115, and input / output terminals 116.

[0379] The pixel section 100A has, for example, a plurality of unit pixels P arranged two-dimensionally in a matrix. For example, pixel drive lines Lread (specifically, row selection lines and reset control lines) are wired to each unit pixel P for each pixel row, and vertical signal lines Lsig are wired to each pixel column. The pixel drive lines Lread transmit drive signals for reading signals from the pixels. One end of each pixel drive line Lread is connected to an output terminal of the vertical drive circuit 111 corresponding to each row.

[0380] The vertical drive circuit 111 is a pixel drive unit that includes a shift register, an address decoder, etc., and drives each unit pixel P of the pixel unit 100A, for example, row by row. Signals output from each unit pixel P of a pixel row selected and scanned by the vertical drive circuit 111 are supplied to a column signal processing circuit 112 through each vertical signal line Lsig. The column signal processing circuit 112 is configured with an amplifier, a horizontal selection switch, etc., provided for each vertical signal line Lsig.

[0381] The horizontal drive circuit 113 is configured with a shift register, an address decoder, etc., and scans and sequentially drives each horizontal selection switch of the column signal processing circuit 112. By selective scanning by this horizontal drive circuit 113, signals of each pixel transmitted through each vertical signal line Lsig are output in sequence to horizontal signal lines 121 and transmitted to the outside of the semiconductor substrate 30 through the horizontal signal lines 121.

[0382] The output circuit 114 processes and outputs signals sequentially supplied from each of the column signal processing circuits 112 via the horizontal signal line 121. The output circuit 114 may perform only buffering, or may perform black level adjustment, column variation correction, various digital signal processing, and the like, for example.

[0383] The circuit portion consisting of the vertical drive circuit 111, the column signal processing circuit 112, the horizontal drive circuit 113, the horizontal signal line 121, and the output circuit 114 may be formed directly on the semiconductor substrate 30, or may be disposed on an external control IC. Furthermore, these circuit portions may be formed on another substrate connected by a cable or the like.

[0384] The control circuit 115 receives a clock and data instructing an operation mode from outside the semiconductor substrate 30, and outputs data such as internal information of the photodetector 100. The control circuit 115 further has a timing generator that generates various timing signals, and controls the driving of peripheral circuits such as the vertical drive circuit 111, the column signal processing circuit 112, and the horizontal drive circuit 113 based on the various timing signals generated by the timing generator.

[0385] The input / output terminal 116 is used to exchange signals with the outside.

[0386] (Application Example 2) Furthermore, the photodetector 100 as described above can be applied to various electronic devices, such as imaging systems such as digital still cameras and digital video cameras, mobile phones with imaging functions, or other devices with imaging functions.

[0387] FIG. 110 is a block diagram showing an example of the configuration of electronic device 1000.

[0388] As shown in Figure 110, electronic device 1000 includes an optical system 1001, a photodetector 100, and a DSP (Digital Signal Processor) 1002, and is configured by connecting DSP 1002, memory 1003, display device 1004, recording device 1005, operation system 1006, and power supply system 1007 via a bus 1008, and is capable of capturing still images and moving images.

[0389] The optical system 1001 is configured to have one or more lenses, and receives incident light (image light) from an object and forms an image on the imaging surface of the photodetector 100 .

[0390] The above-described photodetector 100 is applied as the photodetector 100. The photodetector 100 converts the amount of incident light imaged on an imaging surface by an optical system 1001 into an electrical signal on a pixel-by-pixel basis and supplies the signal to a DSP 1002 as a pixel signal.

[0391] The DSP 1002 performs various signal processing on the signal from the photodetector 100 to acquire an image, and temporarily stores the image data in a memory 1003. The image data stored in the memory 1003 is recorded in a recording device 1005 or supplied to a display device 1004 to display the image. An operation system 1006 accepts various operations by a user and supplies operation signals to each block of the electronic device 1000, and a power supply system 1007 supplies power necessary to drive each block of the electronic device 1000.

[0392] Application Example 3 Fig. 111A schematically illustrates an example of the overall configuration of a light detection system 2000 including the light detection device 100. Fig. 111B illustrates an example of the circuit configuration of the light detection system 2000. The light detection system 2000 includes a light emitting device 2001 serving as a light source unit that emits infrared light L2, and a light detection device 2002 serving as a light receiving unit having a light detection element. The light detection device 100 described above can be used as the light detection device 2002. The light detection system 2000 may further include a system control unit 2003, a light source driving unit 2004, a sensor control unit 2005, a light source side optical system 2006, and a camera side optical system 2007.

[0393] The photodetector 2002 can detect light L1 and light L2. Light L1 is external ambient light reflected by the object (measurement target) 2100 ( FIG. 111A ). Light L2 is light emitted by the light-emitting device 2001 and then reflected by the object 2100. Light L1 is, for example, visible light, and light L2 is, for example, infrared light. Light L1 can be detected by a photoelectric conversion unit in the photodetector 2002, and light L2 can be detected by a photoelectric conversion region in the photodetector 2002. Image information of the object 2100 can be obtained from light L1, and distance information between the object 2100 and the photodetector system 2000 can be obtained from light L2. The photodetector system 2000 can be installed in, for example, an electronic device such as a smartphone or a mobile object such as a car. The light-emitting device 2001 can be configured, for example, by a semiconductor laser, a surface-emitting semiconductor laser, or a vertical-cavity surface-emitting laser (VCSEL). The method of detecting the light L2 emitted from the light-emitting device 2001 by the photodetector 2002 can be, for example, an iTOF method, but is not limited to this. In the iTOF method, the photoelectric conversion unit can measure the distance to the subject 2100, for example, by using the time-of-flight (TOF) of light. The method of detecting the light L2 emitted from the light-emitting device 2001 by the photodetector 2002 can also be, for example, a structured light method or a stereo vision method. For example, in the structured light method, a predetermined pattern of light is projected onto the subject 2100, and the distance between the photodetector system 2000 and the subject 2100 can be measured by analyzing the distortion of the pattern. In addition, in the stereo vision method, for example, two or more cameras are used to acquire two or more images of the subject 2100 viewed from two or more different viewpoints, thereby measuring the distance between the photodetector system 2000 and the subject. The light emitting device 2001 and the light detecting device 2002 can be controlled synchronously by a system control unit 2003 .

[0394] 12. Application Example Application Example to Endoscopic Surgery System The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be applied to an endoscopic surgery system.

[0395] FIG. 112 is a diagram showing an example of the schematic configuration of an endoscopic surgery system to which the technology disclosed herein (the present technology) can be applied.

[0396] Figure 112 shows an operator (doctor) 11131 performing surgery on a patient 11132 on a patient bed 11133 using an endoscopic surgery system 11000. As shown in the figure, the endoscopic surgery system 11000 is composed of an endoscope 11100, other surgical tools 11110 such as an insufflation tube 11111 and an energy treatment tool 11112, a support arm device 11120 that supports the endoscope 11100, and a cart 11200 on which various devices for endoscopic surgery are mounted.

[0397] The endoscope 11100 is composed of a lens barrel 11101, a region of a predetermined length from the tip of which is inserted into a body cavity of a patient 11132, and a camera head 11102 connected to the base end of the lens barrel 11101. In the example shown, the endoscope 11100 is configured as a so-called rigid scope having a rigid lens barrel 11101, but the endoscope 11100 may also be configured as a so-called flexible scope having a flexible lens barrel.

[0398] An opening into which an objective lens is fitted is provided at the tip of the lens barrel 11101. A light source device 11203 is connected to the endoscope 11100, and light generated by the light source device 11203 is guided to the tip of the lens barrel by a light guide extending inside the lens barrel 11101, and is irradiated via the objective lens toward an object to be observed inside the body cavity of the patient 11132. The endoscope 11100 may be a direct-viewing endoscope, an oblique-viewing endoscope, or a side-viewing endoscope.

[0399] An optical system and an image sensor are provided inside the camera head 11102, and light reflected from the object of observation (observation light) is collected onto the image sensor by the optical system. The observation light is photoelectrically converted by the image sensor to generate an electrical signal corresponding to the observation light, i.e., an image signal corresponding to the observed image. The image signal is sent to a camera control unit (CCU) 11201 as RAW data.

[0400] The CCU 11201 is configured with a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc., and comprehensively controls the operations of the endoscope 11100 and the display device 11202. Furthermore, the CCU 11201 receives an image signal from the camera head 11102 and performs various types of image processing on the image signal, such as development processing (demosaic processing), to display an image based on the image signal.

[0401] Under the control of the CCU 11201, the display device 11202 displays an image based on an image signal that has been subjected to image processing by the CCU 11201.

[0402] The light source device 11203 is composed of a light source such as an LED (light emitting diode), and supplies irradiation light to the endoscope 11100 when photographing the surgical site, etc.

[0403] The input device 11204 is an input interface for the endoscopic surgery system 11000. A user can input various information and instructions to the endoscopic surgery system 11000 via the input device 11204. For example, the user inputs an instruction to change the imaging conditions (type of irradiation light, magnification, focal length, etc.) of the endoscope 11100.

[0404] The treatment tool control device 11205 controls the driving of the energy treatment tool 11112 for cauterizing tissue, incising, sealing blood vessels, etc. The insufflation device 11206 inflates the body cavity of the patient 11132 through the insufflation tube 11111 in order to ensure a clear field of view for the endoscope 11100 and a working space for the surgeon. The recorder 11207 is a device capable of recording various types of information related to the surgery. The printer 11208 is a device capable of printing various types of information related to the surgery in various formats such as text, images, or graphs.

[0405] The light source device 11203, which supplies illumination light to the endoscope 11100 when photographing the surgical site, can be configured from a white light source, such as an LED, a laser light source, or a combination of these. When the white light source is configured from a combination of RGB laser light sources, the output intensity and output timing of each color (each wavelength) can be controlled with high precision, allowing the light source device 11203 to adjust the white balance of the captured image. In this case, it is also possible to time-share images corresponding to each RGB by irradiating the object of observation with laser light from each RGB laser light source and controlling the drive of the image sensor of the camera head 11102 in synchronization with the irradiation timing. According to this method, color images can be obtained without providing a color filter to the image sensor.

[0406] Furthermore, the light source device 11203 may be controlled to change the intensity of light it outputs at predetermined time intervals. By controlling the driving of the image sensor of the camera head 11102 in synchronization with the timing of the change in light intensity to acquire images in a time-division manner and combining the images, it is possible to generate an image with a high dynamic range that is free from so-called blocked-up shadows and blown-out highlights.

[0407] The light source device 11203 may also be configured to provide light in a predetermined wavelength range compatible with special light observation. Special light observation, for example, utilizes the wavelength dependence of light absorption in body tissues to irradiate light with a narrower band than the light irradiated during normal observation (i.e., white light), thereby capturing high-contrast images of specific tissues, such as blood vessels on the surface of mucous membranes, known as narrow-band imaging. Alternatively, special light observation may involve fluorescence observation, in which images are obtained using fluorescence generated by irradiating excitation light onto the body tissue. Fluorescence observation may involve irradiating the body tissue with excitation light and observing the fluorescence from the body tissue (autofluorescence observation), or by locally injecting a reagent such as indocyanine green (ICG) into the body tissue and irradiating the body tissue with excitation light corresponding to the fluorescent wavelength of the reagent to obtain a fluorescent image. The light source device 11203 may be configured to provide narrow-band light and / or excitation light compatible with such special light observation.

[0408] FIG. 113 is a block diagram showing an example of the functional configuration of the camera head 11102 and CCU 11201 shown in FIG.

[0409] The camera head 11102 has a lens unit 11401, an imaging unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 has a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other via a transmission cable 11400 so that they can communicate with each other.

[0410] The lens unit 11401 is an optical system provided at the connection portion with the lens barrel 11101. Observation light taken in from the tip of the lens barrel 11101 is guided to the camera head 11102 and enters the lens unit 11401. The lens unit 11401 is composed of a combination of multiple lenses including a zoom lens and a focus lens.

[0411] The imaging unit 11402 may include one imaging element (a so-called single-chip type) or multiple imaging elements (a so-called multi-chip type). When the imaging unit 11402 is configured as a multi-chip type, for example, each imaging element may generate an image signal corresponding to each of RGB, and a color image may be obtained by combining these signals. Alternatively, the imaging unit 11402 may be configured to have a pair of imaging elements for acquiring image signals for the right eye and the left eye corresponding to a 3D (dimensional) display. The 3D display allows the surgeon 11131 to more accurately grasp the depth of the biological tissue at the surgical site. Note that when the imaging unit 11402 is configured as a multi-chip type, multiple lens units 11401 may be provided corresponding to each imaging element.

[0412] Furthermore, the imaging unit 11402 does not necessarily have to be provided in the camera head 11102. For example, the imaging unit 11402 may be provided inside the lens barrel 11101, immediately after the objective lens.

[0413] The driving unit 11403 is configured by an actuator, and moves the zoom lens and focus lens of the lens unit 11401 by a predetermined distance along the optical axis under the control of the camera head control unit 11405. This allows the magnification and focus of the image captured by the imaging unit 11402 to be adjusted appropriately.

[0414] The communication unit 11404 is configured by a communication device for transmitting and receiving various types of information to and from the CCU 11201. The communication unit 11404 transmits the image signal obtained from the imaging unit 11402 to the CCU 11201 via the transmission cable 11400 as RAW data.

[0415] Furthermore, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201 and supplies the control signal to the camera head control unit 11405. The control signal includes information on the imaging conditions, such as information specifying the frame rate of the captured image, information specifying the exposure value at the time of imaging, and / or information specifying the magnification and focus of the captured image.

[0416] The image capturing conditions such as the frame rate, exposure value, magnification, and focus may be appropriately specified by the user, or may be automatically set by the control unit 11413 of the CCU 11201 based on the acquired image signal. In the latter case, the endoscope 11100 is equipped with a so-called AE (Auto Exposure) function, AF (Auto Focus) function, and AWB (Auto White Balance) function.

[0417] The camera head control unit 11405 controls the driving of the camera head 11102 based on a control signal received from the CCU 11201 via the communication unit 11404 .

[0418] The communication unit 11411 is configured by a communication device for transmitting and receiving various information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted from the camera head 11102 via the transmission cable 11400.

[0419] Furthermore, the communication unit 11411 transmits to the camera head 11102 a control signal for controlling the driving of the camera head 11102. The image signal and the control signal can be transmitted by electrical communication, optical communication, or the like.

[0420] The image processing unit 11412 performs various image processing operations on the image signal, which is RAW data transmitted from the camera head 11102 .

[0421] The control unit 11413 performs various controls related to the imaging of the surgical site, etc. by the endoscope 11100 and the display of the captured image obtained by imaging the surgical site, etc. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

[0422] Furthermore, the control unit 11413 displays the captured image showing the surgical site, etc., on the display device 11202 based on the image signal subjected to image processing by the image processing unit 11412. At this time, the control unit 11413 may recognize various objects in the captured image using various image recognition technologies. For example, the control unit 11413 can recognize surgical tools such as forceps, specific biological parts, bleeding, mist generated when using the energy treatment tool 11112, etc., by detecting the shape and color of the edges of objects included in the captured image. When displaying the captured image on the display device 11202, the control unit 11413 may use the recognition results to superimpose various surgical support information on the image of the surgical site. By superimposing the surgical support information and presenting it to the surgeon 11131, the burden on the surgeon 11131 can be reduced and the surgeon 11131 can proceed with the surgery reliably.

[0423] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable for electrical signal communication, an optical fiber for optical communication, or a composite cable of these.

[0424] In the illustrated example, communication is performed wired using a transmission cable 11400, but communication between the camera head 11102 and the CCU 11201 may also be performed wirelessly.

[0425] The above describes an example of an endoscopic surgery system to which the technology according to the present disclosure can be applied. The technology according to the present disclosure can be applied to the imaging unit 11402 among the components described above. By applying the technology according to the present disclosure to the imaging unit 11402, detection accuracy is improved.

[0426] Although an endoscopic surgery system has been described as an example here, the technology disclosed herein may also be applied to other systems, such as a microsurgery system.

[0427] (Application Example to Mobile Object) The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile object, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, a robot, construction machinery, or agricultural machinery (tractor).

[0428] FIG. 114 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology disclosed herein can be applied.

[0429] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 114, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053.

[0430] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0431] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0432] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0433] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 1...

Claims

a photoelectric conversion layer; a first electrode provided on one surface of the photoelectric conversion layer; an oxide semiconductor layer provided between the photoelectric conversion layer and the first electrode; a protective layer provided between the photoelectric conversion layer and the oxide semiconductor layer, the protective layer having an opening at least above the first electrode, the opening having a thickness smaller than that of other regions; a second electrode provided on the other surface of the photoelectric conversion layer opposite to the one surface; A photodetector comprising: 　 the first electrode includes a charge storage electrode capable of storing charge carriers generated by photoelectric conversion and a charge readout electrode disposed apart from the charge storage electrode and reading out the charge carriers; 2. The photodetector according to claim 1, wherein the opening is provided above the charge storage electrode.

2. The photodetector device according to claim 1, wherein the protective layer is made of an oxide or nitride containing at least one of silicon, germanium, aluminum, hafnium, lanthanum, strontium, zirconium, vanadium, tantalum, titanium, yttrium, magnesium, carbon, tin, erbium, ytterbium, and gadolinium.

2. The photodetector according to claim 1, wherein the protective layer is composed of one or more layers, and when an energy level of a conduction band minimum of one of the one or more layers is Ecn, an energy level of a lowest unoccupied molecular orbital of the photoelectric conversion layer is Eco, and an energy level of a conduction band minimum of the oxide semiconductor layer is Ecm, Ecm > Eco and Ecn < Eco are satisfied. 　 the protective layer has the opening and a non-opening portion provided in the other region and having a thickness greater than that of the opening, 2. The photodetector according to claim 1, wherein the non-opening portion has a film thickness of 1 nm or more and 100 nm or less, and the opening portion has a film thickness of 0 nm or more and 5 nm or less. 　 The photodetector device according to claim 2 , wherein the protective layer further includes the opening above the charge readout electrode. 　 The photodetector device according to claim 1 , wherein the protective layer includes a first layer having a constant thickness and a second layer having the opening.

8. The photodetector according to claim 7, wherein the first layer has a thickness of at least one atomic layer and at most 5 nm.

8. The photodetector according to claim 7, wherein, when an energy level of the conduction band minimum of the first layer is Ecn', an energy level of a lowest unoccupied molecular orbital of the photoelectric conversion layer is Eco, and an energy level of the conduction band minimum of the oxide semiconductor layer is Ecm, Ecn'<Eco, or Ecn'<Ecm, or Eco<Ecn'<Ecm is satisfied. 　 The photodetector according to claim 1 , wherein the charge carrier concentration in the region of the oxide semiconductor layer above which the opening is formed is greater by at least one order of magnitude than the charge carrier concentration in the surrounding area. 　 The photodetector according to claim 1 , wherein the photoelectric conversion layer and the oxide semiconductor layer are in direct contact with each other in the opening. 　 further comprising a plurality of pixels arranged in a two-dimensional array; 3. The photodetector according to claim 2, wherein the first electrode further includes a transfer electrode provided between the charge readout electrode and the charge storage electrode, for controlling a flow of the charge carriers from the charge storage electrode to the charge readout electrode, and a pixel separation electrode provided between adjacent pixels and to which a fixed potential is applied. 　 The photodetector device according to claim 12 , wherein the protective layer has the other region above the transfer electrode and the pixel separation electrode. 　 the protective layer has the opening and a non-opening portion provided in the other region and having a thickness greater than that of the opening, The photodetector according to claim 1 , wherein at least a portion of the non-opening portion is covered with an electron transport layer having a higher mobility of charge carriers than the photoelectric conversion layer.

15. The photodetector according to claim 14, wherein the electron transport layer is formed to contain one or more types of inorganic semiconductors or organic semiconductors. 　 the protective layer includes a second layer having the opening and exposing the oxide semiconductor layer at a bottom of the opening, and a first layer having a constant film thickness and covering an upper surface and a side surface of the second layer and the oxide semiconductor layer exposed at the bottom of the opening; The photodetector device of claim 14 , wherein the electron transport layer is deposited on the first layer. 　 a hole blocking layer covering the top and side surfaces of the non-opening portion and the bottom surface of the opening portion; The photodetector according to claim 5 , wherein the energy level of the upper end of the valence band of the oxide semiconductor layer is deeper than the energy level of the upper end of the valence band of the hole blocking layer. 　 The photodetector according to claim 17 , wherein the hole blocking layer has an oxygen areal density lower than the oxygen areal density of the oxide semiconductor layer.

2. The photodetector according to claim 1, wherein the protective layer is made up of one or more layers, and when an energy level of a valence band top of one of the one or more layers is Evn and an energy level of a highest occupied molecular orbital of the photoelectric conversion layer is Evo, Evn>Evo is satisfied. 　 a hole blocking layer covering the top and side surfaces of the non-opening portion and the bottom surface of the opening portion; The photodetector according to claim 5 , wherein the hole blocking layer has a thickness of 1 nm to 50 nm. 　 a charge transport layer on the one surface side of the photoelectric conversion layer, the protective layer has the opening and a non-opening portion provided in the other region and having a thickness greater than that of the opening, The photodetector according to claim 1 , wherein the charge transport layer is divided between the opening and the non-opening.

22. The photodetector device of claim 21, wherein a height difference between the opening and the non-opening of the protective layer is five times or more the thickness of the charge transport layer. 　 The light detection device according to claim 21 , wherein the non-opening portion has a cross-sectional shape of an inverse tapered or eaves type, or a trapezoidal groove in a surface thereof.

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