Detection device

Abstract

This detection device comprises: a substrate; a plurality of photodiodes in which a lower electrode, a lower buffer layer, an active layer, an upper buffer layer, and an upper electrode are stacked in order on the substrate; and an insulating film that is provided between the plurality of adjacent lower electrodes. The lower buffer layer includes an electrode-overlapping portion that overlaps with the lower electrode and an insulating-film-overlapping portion that overlaps at least a portion of the insulating film, the thickness of the insulating-film-overlapping portion of the lower buffer layer being less than the thickness of the electrode-overlapping portion of the lower buffer layer.

Description

Detection device

[0001] The present invention relates to a detection device.

[0002] Optical sensors capable of detecting fingerprint patterns and vein patterns are known (see, for example, Patent Document 1). Such optical sensors have multiple photodiodes (OPDs: Organic Photodiodes) that use an organic semiconductor material as an active layer. As described in Patent Document 2, the photodiodes are stacked, for example, in the following order: a lower electrode, an electron transport layer, an active layer, a hole transport layer, and an upper electrode. The electron transport layer or the hole transport layer is also called a buffer layer.

[0003] JP 2009-32005 A International Publication No. 2020 / 188959

[0004] When the buffer layer and the active layer are provided across multiple photodiodes, more specifically, when the buffer layer is provided across multiple adjacent lower electrodes, leakage current may occur between adjacent lower electrodes.

[0005] An object of the present invention is to provide a detection device capable of suppressing leakage current between electrodes.

[0006] A detection device according to one embodiment of the present invention includes a substrate, a plurality of photodiodes stacked on the substrate in the following order: a lower electrode, a lower buffer layer, an active layer, an upper buffer layer, and an upper electrode, and an insulating film provided between adjacent lower electrodes, wherein the lower buffer layer includes an electrode overlapping portion that overlaps the lower electrode and an insulating film overlapping portion that overlaps at least a portion of the insulating film, and the thickness of the insulating film overlapping portion of the lower buffer layer is thinner than the thickness of the electrode overlapping portion of the lower buffer layer.

[0007] FIG. 1 is a plan view schematically showing a detection device according to a first embodiment. FIG. 2 is a block diagram showing an example of the configuration of the detection device according to the first embodiment. FIG. 3 is a circuit diagram showing the detection device according to the first embodiment. FIG. 4 is an enlarged schematic configuration view of a sensor unit. FIG. 5 is a VV' cross-sectional view of FIG. 4. FIG. 6 is a plan view schematically showing the positional relationship between a lower electrode and an insulating film. FIG. 7 is a VII-VII' cross-sectional view of FIG. 6. FIG. 8 is a plan view schematically showing the positional relationship between a lower electrode and an insulating film of a detection device according to a second embodiment. FIG. 9 is a IX-IX' cross-sectional view of FIG. 8. FIG. 10 is a plan view schematically showing the positional relationship between a lower electrode and an insulating film of a detection device according to a third embodiment. FIG. 11 is a XI-XI' cross-sectional view of FIG. 10. FIG. 12 is a cross-sectional view schematically showing a detection device according to a fourth embodiment. FIG. 13 is a cross-sectional view schematically showing a detection device according to a modification of the fourth embodiment.

[0008] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present disclosure is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially identical. Furthermore, the components described below can be combined as appropriate. Note that the disclosure is merely an example, and any appropriate modifications that a person skilled in the art can easily conceive while maintaining the gist of the present disclosure are naturally included within the scope of the present disclosure. Furthermore, for clarity of explanation, the drawings may schematically depict the width, thickness, shape, etc. of each part compared to the actual embodiment. However, these are merely examples and are not intended to limit the interpretation of the present disclosure. Furthermore, in this disclosure and each figure, elements similar to those described above with reference to the previous figures may be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0009] In this specification and claims, when expressing an aspect of placing another structure on top of a certain structure, the term "on top" is used, unless otherwise specified, to include both a case in which another structure is placed directly on top of a certain structure so as to be in contact with the certain structure, and a case in which another structure is placed above a certain structure via yet another structure.

[0010] First Embodiment Fig. 1 is a plan view showing a detection device according to the first embodiment. As shown in Fig. 1, the detection device 1 has a sensor substrate 21 (substrate), a sensor unit 10, a gate line drive circuit 15, a signal line selection circuit 16, a detection circuit 48, a control circuit 122, a power supply circuit 123, a first light source substrate 51, a second light source substrate 52, and light sources 53 and 54. The first light source substrate 51 is provided with a plurality of light sources 53. The second light source substrate 52 is provided with a plurality of light sources 54.

[0011] A control board 121 is electrically connected to the sensor substrate 21 via a wiring board 71. The wiring board 71 is, for example, a flexible printed circuit board or a rigid board. The wiring board 71 is provided with a detection circuit 48. The control board 121 is provided with a control circuit 122 and a power supply circuit 123. The control circuit 122 is, for example, an FPGA (Field Programmable Gate Array). The control circuit 122 supplies control signals to the sensor unit 10, the gate line driving circuit 15, and the signal line selection circuit 16 to control the detection operation of the sensor unit 10. The control circuit 122 also supplies control signals to the light sources 53 and 54 to control the lighting or non-lighting of the light sources 53 and 54. The power supply circuit 123 supplies voltage signals, such as a sensor power supply signal VDDSNS (see FIG. 3), to the sensor unit 10, the gate line driving circuit 15, and the signal line selection circuit 16. Furthermore, the power supply circuit 123 supplies a power supply voltage to the light sources 53 and 54 .

[0012] The sensor substrate 21 has a detection area AA and a peripheral area GA. The detection area AA is an area where multiple photodiodes PD (see FIG. 4) of the sensor unit 10 are provided. The peripheral area GA is an area between the outer periphery of the detection area AA and the outer edge of the sensor substrate 21, and is an area where multiple photodiodes PD are not provided.

[0013] The gate line driving circuit 15 and the signal line selection circuit 16 are provided in the peripheral area GA. Specifically, the gate line driving circuit 15 is provided in a region of the peripheral area GA extending along the second direction Dy. The signal line selection circuit 16 is provided in a region of the peripheral area GA extending along the first direction Dx, and is provided between the sensor unit 10 and the detection circuit 48.

[0014] In the following description, the first direction Dx is a direction in a plane parallel to the sensor substrate 21. The second direction Dy is a direction in a plane parallel to the sensor substrate 21, and is a direction perpendicular to the first direction Dx. The second direction Dy may intersect the first direction Dx without being perpendicular to it. The third direction Dz is a direction perpendicular to the first direction Dx and the second direction Dy, and is the normal direction to the main surface of the sensor substrate 21. Furthermore, "planar view" refers to the positional relationship when viewed from a direction perpendicular to the sensor substrate 21.

[0015] The plurality of light sources 53 are provided on the first light source substrate 51 and arranged along the second direction Dy. The plurality of light sources 54 are provided on the second light source substrate 52 and arranged along the second direction Dy. The first light source substrate 51 and the second light source substrate 52 are electrically connected to the control circuit 122 and the power supply circuit 123 via terminal portions 124 and 125 provided on the control board 121, respectively.

[0016] For example, inorganic light emitting diodes (LEDs) or organic light emitting diodes (OLEDs) are used as the light sources 53 and 54. The light sources 53 and 54 emit light of different wavelengths.

[0017] The first light emitted from the light source 53 is mainly reflected by the surface of the object to be detected, such as a finger, and enters the sensor unit 10. As a result, the sensor unit 10 can detect a fingerprint by detecting the shape of the projections and recesses on the surface of the finger or the like. The second light emitted from the light source 54 is mainly reflected by the inside of the finger or the like or passes through the finger or the like and enters the sensor unit 10. As a result, the sensor unit 10 can detect information about the living body inside the finger or the like. The information about the living body includes, for example, the pulse wave, pulse rate, and blood vessel image of the finger or palm. In other words, the detection device 1 may be configured as a fingerprint detection device that detects fingerprints, or a vein detection device that detects blood vessel patterns such as veins.

[0018] The arrangement of the light sources 53, 54 shown in FIG. 1 is merely an example and can be changed as appropriate. The detection device 1 is provided with multiple types of light sources 53, 54 as light sources. However, this is not limited to this, and the light source may be of one type. For example, multiple light sources 53 and multiple light sources 54 may be arranged on the first light source substrate 51 and the second light source substrate 52, respectively. Furthermore, the number of light source substrates on which the light sources 53 and the light sources 54 are arranged may be one or three or more. Alternatively, it is sufficient that at least one or more light sources are arranged.

[0019] 2 is a block diagram showing an example of the configuration of the detection device according to the first embodiment. As shown in FIG. 2, the detection device 1 further includes a detection control circuit 11 and a detection unit 40. Some or all of the functions of the detection control circuit 11 are included in a control circuit 122. In addition, some or all of the functions of the detection unit 40 other than the detection circuit 48 are included in the control circuit 122.

[0020] The sensor unit 10 has a plurality of photodiodes PD. The photodiodes PD of the sensor unit 10 output electrical signals corresponding to the incident light as detection signals Vdet to the signal line selection circuit 16. The sensor unit 10 also performs detection in accordance with a gate drive signal VGL supplied from the gate line drive circuit 15.

[0021] The detection control circuit 11 is a circuit that supplies control signals to the gate line drive circuit 15, the signal line selection circuit 16, and the detection unit 40, respectively, and controls their operations. The detection control circuit 11 supplies various control signals, such as a start signal STV and a clock signal CK, to the gate line drive circuit 15. The detection control circuit 11 also supplies various control signals, such as a selection signal ASW, to the signal line selection circuit 16. The detection control circuit 11 also supplies various control signals to the light sources 53 and 54, and controls the lighting and non-lighting of each.

[0022] The gate line driving circuit 15 is a circuit that drives a plurality of gate lines GL (see FIG. 3) based on various control signals. The gate line driving circuit 15 sequentially or simultaneously selects the plurality of gate lines GL and supplies a gate driving signal VGL to the selected gate lines GL. In this way, the gate line driving circuit 15 selects a plurality of photodiodes PD connected to the gate lines GL.

[0023] The signal line selection circuit 16 is a switch circuit that sequentially or simultaneously selects a plurality of signal lines SL (see FIG. 3 ). The signal line selection circuit 16 is, for example, a multiplexer. The signal line selection circuit 16 connects the selected signal line SL to the detection circuit 48 based on a selection signal ASW supplied from the detection control circuit 11. As a result, the signal line selection circuit 16 outputs a detection signal Vdet of the photodiode PD to the detection unit 40.

[0024] The detection unit 40 includes a detection circuit 48, a signal processing circuit 44, a coordinate extraction circuit 45, a memory circuit 46, and a detection timing control circuit 47. The detection timing control circuit 47 controls the detection circuit 48, the signal processing circuit 44, and the coordinate extraction circuit 45 based on a control signal supplied from the detection control circuit 11 so that they operate in synchronization with each other.

[0025] The detection circuit 48 is, for example, an analog front end (AFE) circuit. The detection circuit 48 is a signal processing circuit that has at least the functions of a detection signal amplifier circuit 42 and an A / D conversion circuit 43. The detection signal amplifier circuit 42 amplifies the detection signal Vdet. The A / D conversion circuit 43 converts the analog signal output from the detection signal amplifier circuit 42 into a digital signal.

[0026] The signal processing circuit 44 is a logic circuit that detects a predetermined physical quantity input to the sensor unit 10 based on the output signal of the detection circuit 48. When a finger touches or approaches the detection surface, the signal processing circuit 44 can detect unevenness on the surface of the finger or palm based on the signal from the detection circuit 48. The signal processing circuit 44 can also detect information about the living body based on the signal from the detection circuit 48. The information about the living body includes, for example, an image of the blood vessels of the finger or palm, a pulse wave, a pulse rate, and a blood oxygen concentration.

[0027] The memory circuit 46 temporarily stores the signals calculated by the signal processing circuit 44. The memory circuit 46 may be, for example, a RAM (Random Access Memory), a register circuit, or the like.

[0028] The coordinate extraction circuit 45 is a logic circuit that calculates the detected coordinates of the unevenness of the surface of a finger or the like when the signal processing circuit 44 detects contact or proximity of a finger. The coordinate extraction circuit 45 is also a logic circuit that calculates the detected coordinates of the blood vessels of the finger or palm. The coordinate extraction circuit 45 combines the detection signals Vdet output from each photodiode PD of the sensor unit 10 to generate two-dimensional information indicating the shape of the unevenness of the surface of the finger or the like and two-dimensional information indicating the shape of the blood vessels of the finger or palm. The coordinate extraction circuit 45 may output the detection signal Vdet as the sensor output voltage Vo without calculating the detection coordinates.

[0029] 3 is a circuit diagram showing the detection device according to the first embodiment. The circuit configuration of a detection circuit 48 is also shown in FIG. 3. As shown in FIG. 3, a sensor pixel PX includes a photodiode PD, a capacitance element Ca, and a drive transistor Tr. The capacitance element Ca is a capacitance (sensor capacitance) formed in the photodiode PD, and is equivalently connected in parallel with the photodiode PD.

[0030] 3 shows two gate lines GL(m) and GL(m+1) arranged in the second direction Dy among the multiple gate lines GL. Also, two signal lines SL(n) and SL(n+1) arranged in the first direction Dx among the multiple signal lines SL. A sensor pixel PX is an area surrounded by the gate line GL and the signal line SL.

[0031] The drive transistors Tr are provided corresponding to the respective photodiodes PD. The drive transistors Tr are configured by thin film transistors, and in this example, are configured by n-channel MOS (Metal Oxide Semiconductor) type TFTs (Thin Film Transistors).

[0032] Each of the gate lines GL is connected to the gates of a plurality of drive transistors Tr arranged in a first direction Dx. Each of the signal lines SL is connected to one of the source and drain of a plurality of drive transistors Tr arranged in a second direction Dy. The other of the source and drain of each of the drive transistors Tr is connected to the anode of the photodiode PD and the capacitance element Ca.

[0033] A sensor power supply signal VDDSNS is supplied to the cathode of the photodiode PD from the power supply circuit 123 (see FIG. 1 ). A sensor reference voltage COM, which serves as the initial potential of the signal line SL and the capacitance element Ca, is supplied to the signal line SL and the capacitance element Ca from the power supply circuit 123 via the reset transistor TrR.

[0034] When light is irradiated onto the sensor pixel PX during the exposure period, a current corresponding to the amount of light flows through the photodiode PD, causing charge to accumulate in the capacitance element Ca. When the drive transistor Tr is turned on during the readout period, a current corresponding to the charge accumulated in the capacitance element Ca flows through the signal line SL. The signal line SL is connected to the detection circuit 48 via the output transistor TrS of the signal line selection circuit 16. This allows the detection device 1 to detect a signal corresponding to the amount of light irradiated onto the photodiode PD for each sensor pixel PX.

[0035] During the readout period, the switch SSW of the detection circuit 48 is turned on, connecting the detection circuit 48 to the signal line SL. The detection signal amplifier circuit 42 of the detection circuit 48 converts fluctuations in current supplied from the signal line SL into voltage fluctuations and amplifies the voltage fluctuations. A reference potential (Vref) having a fixed potential is input to the non-inverting input (+) of the detection signal amplifier circuit 42, and the signal line SL is connected to the inverting input (-). In this embodiment, a signal equal to the sensor reference voltage COM is input as the reference potential (Vref) voltage. The control circuit 122 (see FIG. 1) calculates the difference between the detection signal Vdet when light is irradiated and the detection signal Vdet when light is not irradiated as the sensor output voltage Vo. The detection signal amplifier circuit 42 also includes a capacitance element Cb and a reset switch RSW. During the reset period, the reset switch RSW is turned on, resetting the charge in the capacitance element Cb.

[0036] The driving transistor Tr is not limited to an n-type TFT, but may be a p-type TFT. The pixel circuit of the sensor pixel PX shown in Fig. 3 is merely an example, and the sensor pixel PX may be provided with multiple transistors corresponding to one photodiode PD.

[0037] Next, the configuration of the photodiode PD will be described. FIG. 4 is an enlarged schematic diagram of the sensor unit. As shown in FIG. 4, the detection device 1 has a plurality of photodiodes PD provided on a sensor substrate 21 and an insulating film 35. A plurality of gate lines GL each extend in a first direction Dx and are arranged at intervals in a second direction Dy. A plurality of signal lines SL each extend in the second direction Dy and are arranged at intervals in the first direction Dx. The plurality of photodiodes PD are provided in an area surrounded by two gate lines GL and two signal lines SL, and are arranged in a matrix on the sensor substrate 21.

[0038] Furthermore, lower electrodes 23 of the photodiodes PD are provided in a matrix on the sensor substrate 21 corresponding to each of the multiple photodiodes PD. In the example shown in FIG. 4 , the right and bottom edges of the lower electrodes 23 are provided so as to overlap with parts of the signal lines SL and gate lines GL, respectively. The left and top edges of the lower electrodes 23 are disposed at intervals from the signal lines SL and gate lines GL, respectively. This allows the area of ​​the lower electrodes 23 to be increased in the region surrounded by two gate lines GL and two signal lines SL, thereby improving the detection sensitivity of the photodiodes PD.

[0039] The drive transistor Tr is provided in a region overlapping with the lower electrode 23 of the photodiode PD. Specifically, the drive transistor Tr has a semiconductor layer 61, a source electrode 62, a drain electrode 63, and a gate electrode 64. The semiconductor layer 61 extends along the gate line GL and is provided so as to intersect with the gate electrode 64 in a plan view. The gate electrode 64 is connected to the gate line GL and extends in a direction (second direction Dy) perpendicular to the gate line GL.

[0040] One end of the semiconductor layer 61 is connected to a source electrode 62 via a contact hole CH2. The source electrode 62 is connected to a connection wiring 65 and a connection pad 66, and is drawn out to the center of the photodiode PD (lower electrode 23). The lower electrode 23 is connected to the connection pad 66 at its center via a contact hole CH1. With this configuration, the source electrode 62 of the drive transistor Tr is electrically connected to the photodiode PD. The other end of the semiconductor layer 61 is connected to a drain electrode 63 via a contact hole CH3. The drain electrode 63 is connected to a signal line SL.

[0041] The insulating film 35 is provided between adjacent lower electrodes 23 in the first direction Dx and the second direction Dy, and is provided to cover the peripheral portions of the lower electrodes 23. More specifically, the insulating film 35 is formed in a lattice pattern with first extending portions 35a and second extending portions 35b intersecting each other. The first extending portions 35a extend in the second direction Dy. The first extending portions 35a are provided overlapping with the signal lines SL and extending along the signal lines SL. The second extending portions 35b extend in the first direction Dx. The second extending portions 35b are provided overlapping with the gate lines GL and extending along the gate lines GL.

[0042] In other words, openings OP are formed in the insulating film 35 in regions overlapping with the plurality of lower electrodes 23. The openings OP are regions surrounded by two first extension portions 35a and two second extension portions 35b. The island-shaped portion 35c is provided at a distance from the first extension portion 35a and the second extension portion 35b, and is provided in a region overlapping with the contact hole CH1 in the center of the photodiode PD (lower electrode 23).

[0043] The shapes, arrangement pitch, etc. of the lower electrode 23 and insulating film 35 shown in FIG. 4 are merely examples, and can be changed as appropriate depending on the characteristics and detection accuracy required of the detection device 1.

[0044] 5 is a cross-sectional view taken along the line VV' in FIG. 4. As shown in FIG. 5, the detection device 1 includes a circuit formation layer 29, an insulating film 27, a photodiode PD, and a sealing film 90 stacked in this order on a sensor substrate 21. The sensor substrate 21 is an insulating substrate, and may be, for example, a glass substrate made of quartz, alkali-free glass, or the like. The sensor substrate 21 is not limited to a flat plate shape, and may have a curved surface. In this case, the sensor substrate 21 may be made of a film-like resin material.

[0045] The circuit formation layer 29 is provided on the sensor substrate 21, and is a layer on which various transistors such as the drive transistors Tr shown in Figures 3 and 4, and various wirings such as the gate lines GL and signal lines SL are formed. Figure 5 shows the signal lines SL connected to the drive transistors Tr. The insulating film 27 is provided on the circuit formation layer 29 including the drive transistors Tr, covering the signal lines SL. The insulating film 27 is an organic planarizing film made of an organic insulating material.

[0046] The insulating film 28 is provided on the insulating film 27. The insulating film 28 is a barrier film made of an inorganic insulating material such as a silicon nitride (SiN) film.

[0047] The photodiode PD and the insulating film 35 are provided on the insulating film 28. More specifically, the photodiode PD has a lower electrode 23, a lower buffer layer 32, an active layer 31, an upper buffer layer 33, and an upper electrode 24. In the photodiode PD, the lower electrode 23, the lower buffer layer 32 (hole transport layer), the active layer 31, the upper buffer layer 33 (electron transport layer), and the upper electrode 24 are stacked in this order in a direction perpendicular to the sensor substrate 21. The photodiode PD of this embodiment is an OPD (organic photodiode) in which an organic semiconductor is used as the active layer 31.

[0048] The lower electrode 23 is an anode electrode of the photodiode PD and is formed of a light-transmitting conductive material such as ITO (Indium Tin Oxide). The lower electrode 23 is provided separately for each photodiode PD. The lower buffer layer 32, active layer 31, upper buffer layer 33, and upper electrode 24 are provided continuously across multiple photodiodes PD. Specifically, the lower buffer layer 32, active layer 31, upper buffer layer 33, and upper electrode 24 are provided so as to overlap the lower electrode 23 of the adjacent photodiode PD-1 and the lower electrode 23 of the photodiode PD-2, and also so as to overlap the insulating film 35 between the photodiodes PD-1 and PD-2.

[0049] The insulating film 35 (first extending portion 35a) is provided on the insulating film 28 between adjacent lower electrodes 23, and covers the peripheral edge of the lower electrode 23. In this embodiment, the insulating film 35 is a silicon nitride film (SiN) or a silicon oxide film (SiO ２ The insulating film 35 (first extending portion 35a) insulates the lower electrodes 23 of adjacent photodiodes PD. The detailed configuration of the insulating film 35 will be described later with reference to FIGS. 6 and 7.

[0050] Furthermore, contact hole CH1 is provided in the center of lower electrode 23, penetrating insulating film 27 in the thickness direction (third direction Dz). Lower electrode 23 is connected to connection pad 66 at the bottom of contact hole CH1. Island-shaped portion 35c is provided to cover contact hole CH1 and covers lower electrode 23 inside contact hole CH1. Island-shaped portion 35c overlaps connection pad 66 in plan view. With this configuration, even if a step occurs in lower buffer layer 32 (hole transport layer) inside contact hole CH1, the island-shaped portion 35c is provided, thereby preventing a short circuit between active layer 31 and lower electrode 23.

[0051] The active layer 31 changes its characteristics (e.g., voltage-current characteristics and resistance value) depending on the light irradiated thereto. An organic material is used as the material for the active layer 31. Specifically, the active layer 31 has a bulk heterostructure in which a p-type organic semiconductor and an n-type organic semiconductor, an n-type fullerene derivative (PCBM), are mixed. Examples of low-molecular-weight organic materials that can be used for the active layer 31 include C60 (fullerene), PCBM (phenyl C61-butyric acid methyl ester), CuPc (copper phthalocyanine), F16CuPc (fluorinated copper phthalocyanine), rubrene (5,6,11,12-tetraphenyltetracene), and PDI (perylene derivative).

[0052] The active layer 31 can be formed using these low-molecular-weight organic materials by a vapor deposition (dry process). In this case, the active layer 31 may be, for example, a laminated film of CuPc and F16CuPc, or a laminated film of rubrene and C60. The active layer 31 can also be formed by a coating (wet process). In this case, the active layer 31 is made of a material that combines the above-mentioned low-molecular-weight organic material with a high-molecular-weight organic material. Examples of high-molecular-weight organic materials that can be used include P3HT (poly(3-hexylthiophene)) and F8BT (F8-alt-benzothiadiazole). The active layer 31 can be a film in which P3HT and PCBM are mixed, or a film in which F8BT and PDI are mixed.

[0053] The lower buffer layer 32 is a hole transport layer, and the upper buffer layer 33 is an electron transport layer. The lower buffer layer 32 and the upper buffer layer 33 are provided to facilitate the holes and electrons generated in the active layer 31 reaching the lower electrode 23 or the upper electrode 24. The lower buffer layer 32 (hole transport layer) is in direct contact with the upper surface of the lower electrode 23, and is also provided on the insulating film 35 between adjacent lower electrodes 23. The active layer 31 is in direct contact with the upper surface of the lower buffer layer 32. The material of the hole transport layer is a metal oxide layer. As the metal oxide layer, tungsten oxide (WO ３), molybdenum oxide, etc. are used.

[0054] The upper buffer layer 33 (electron transport layer) is in direct contact with the active layer 31, and the upper electrode 24 is in direct contact with the upper buffer layer 33. Ethoxylated polyethyleneimine (PEIE) is used as the material for the electron transport layer.

[0055] The materials and manufacturing methods of the lower buffer layer 32, the active layer 31, and the upper buffer layer 33 are merely examples, and other materials and manufacturing methods may be used. For example, the lower buffer layer 32 and the upper buffer layer 33 are not limited to single-layer films, and may be formed as multilayer films including an electron blocking layer and a hole blocking layer.

[0056] The upper electrode 24 is provided on the upper buffer layer 33. The upper electrode 24 is a cathode electrode of the photodiode PD and is formed continuously over the entire detection area AA. In other words, the upper electrode 24 is provided continuously over the multiple photodiodes PD. The upper electrode 24 faces the multiple lower electrodes 23, with the lower buffer layer 32, the active layer 31, and the upper buffer layer 33 interposed therebetween. The upper electrode 24 is formed of a light-transmitting conductive material such as ITO or IZO. The upper electrode 24 may also be a laminated film of multiple light-transmitting conductive materials.

[0057] The sealing film 90 is provided on the upper electrode 24. The sealing film 90 is made of an inorganic film such as a silicon nitride film or an aluminum oxide film, or a resin film such as acrylic. The sealing film 90 is not limited to a single layer, but may be a laminated film of two or more layers combining the inorganic film and the resin film. The sealing film 90 effectively seals the photodiode PD and can prevent moisture from entering from the upper surface side.

[0058] 4 and 5 are merely examples and can be modified as appropriate. For example, the upper electrode 24 may be the anode electrode of the photodiode PD, and the lower electrode 23 may be the cathode electrode of the photodiode PD.

[0059] Next, the detailed configurations of the insulating film 35, the lower electrode 23, and the lower buffer layer 32 will be described. Fig. 6 is a plan view schematically showing the positional relationship between the lower electrode and the insulating film. Fig. 7 is a cross-sectional view taken along line VII-VII' in Fig. 6. In Fig. 6, the insulating film 35 is shown hatched to make the drawing easier to see. Fig. 7 is an enlarged cross-sectional view of region A indicated by the dashed line in Fig. 5.

[0060] 6 , the insulating film 35 is provided in a grid pattern, covering the peripheral edges of the lower electrodes 23. The first extending portions 35a are provided between the lower electrodes 23 adjacent to each other in the first direction Dx, and extend in the second direction Dy along the sides of the lower electrodes 23. The second extending portions 35b are provided between the lower electrodes 23 adjacent to each other in the second direction Dy, and extend in the first direction Dx along the sides of the lower electrodes 23.

[0061] The insulating film 35 (first extension portion 35a and second extension portion 35b) has a plurality of grooves 35G extending between adjacent lower electrodes 23 along the sides of the lower electrodes 23. The grooves 35G are located between adjacent lower electrodes 23 and are provided to surround the lower electrodes 23 in a plan view.

[0062] 6 and 7 , in this embodiment, two grooves 35G are provided between adjacent lower electrodes 23. The two grooves 35G extend along the extension directions of the first extension portion 35a and the second extension portion 35b, respectively, and are provided adjacent to each other in the width direction of the first extension portion 35a and the second extension portion 35b. In other words, between adjacent lower electrodes 23, the insulating film 35 (the first extension portion 35a and the second extension portion 35b) is separated into three parts by the two grooves 35G.

[0063] Specifically, in the photodiodes PD-1 and PD-2 adjacent to each other in the first direction Dx, the insulating film 35 has electrode side overlapping portions 35e and 35g separated by two grooves 35G, and a protrusion 35f. The electrode side overlapping portion 35e is provided overlapping the side of the lower electrode 23 of the photodiode PD-1 and extends along the side of the lower electrode 23 (the right side in FIG. 6). The electrode side overlapping portion 35g is provided overlapping the side of the lower electrode 23 of the photodiode PD-2 (the left side in FIG. 6) and extends along the side of the lower electrode 23. The protrusion 35f is located between the two grooves 35G and extends along the electrode side overlapping portions 35e and 35g.

[0064] The electrode side overlapping portions 35e and 35g each overlap four sides of the lower electrode 23 and are formed in a frame shape surrounding the lower electrode 23. Furthermore, the protrusions 35f are provided at positions between the lower electrodes 23 that do not overlap with the lower electrodes 23. The protrusions 35f are provided in a lattice pattern so as to surround each of the lower electrodes 23 arranged in a matrix.

[0065] The width (width in the first direction Dx) of the convex portion 35f is smaller than the width (width in the first direction Dx) of the multiple groove portions 35G and is also smaller than the spacing between adjacent multiple lower electrodes 23. The thickness of the insulating film 35 (electrode side overlapping portions 35e, 35g and convex portion 35f) provided between adjacent multiple lower electrodes 23 is, for example, not less than 20 nm and not more than 200 nm. The film thickness of the lower electrode 23 is, for example, not less than 20 nm and not more than 100 nm.

[0066] 7 , the lower buffer layer 32 covers at least a portion of the lower electrode 23 of the photodiode PD-1, the lower electrode 23 of the photodiode PD-2, and the insulating film 35, which are adjacent in the first direction Dx, and is also provided inside the two grooves 35G. More specifically, the lower buffer layer 32 includes an electrode overlapping portion 32a overlapping the lower electrode 23, insulating film overlapping portions 32b, 32c, and 32d overlapping at least a portion of the insulating film 35, and a groove overlapping portion 32e provided on the insulating film 28 inside the groove 35G.

[0067] The electrode overlapping portion 32a is provided in a region of the lower electrode 23 where the insulating film 35 is not provided (opening OP (see FIG. 4)). The insulating film overlapping portion 32b is provided on the electrode side overlapping portion 35e of the insulating film 35. The insulating film overlapping portion 32c is provided on the convex portion 35f of the insulating film 35. The insulating film overlapping portion 32d is provided on the electrode side overlapping portion 35g of the insulating film 35.

[0068] In this embodiment, the lower buffer layer 32 is formed by, for example, a coating method to cover the lower electrode 23 and the insulating film 35. As a result, the lower buffer layer 32 tends to accumulate in the recess formed by the groove 35G, the protrusion 35f, and the electrode side overlapping portions 35e and 35g, and also tends to accumulate in the recess formed by the lower electrode 23 and the electrode side overlapping portions 35e and 35g of the insulating film 35 (i.e., the region overlapping with the opening OP (see FIG. 4)). On the other hand, the lower buffer layer 32 applied on the insulating film 35 flows from above the insulating film 35 toward the groove 35G or the lower electrode 23, thereby forming a thin layer.

[0069] As a result, in this embodiment, the thicknesses t2, t3, and t4 of the insulating film overlapping portions 32b, 32c, and 32d of the lower buffer layer 32 are thinner than the thickness t1 of the electrode overlapping portion 32a of the lower buffer layer 32. In addition, the thicknesses t2, t3, and t4 of the insulating film overlapping portions 32b, 32c, and 32d of the lower buffer layer 32 are thinner than the thickness t5 of the trench overlapping portion 32e of the lower buffer layer 32.

[0070] With this configuration, the insulating film overlapping portions 32b, 32c, and 32d of the lower buffer layer 32 located between adjacent lower electrodes 23 have a higher resistance value than the electrode overlapping portion 32a. Therefore, the lower buffer layer 32 (insulating film overlapping portions 32b, 32c, and 32d) in the region overlapping with the insulating film 35 functions as a potential barrier between adjacent lower electrodes 23. Therefore, in this embodiment, the leakage current flowing between adjacent lower electrodes 23 can be suppressed more effectively than when the lower buffer layer 32 is provided continuously with a constant thickness across multiple adjacent photodiodes PD.

[0071] Furthermore, the lower buffer layer 32 provided on the insulating film 35 is discontinuous at steps formed by the grooves 35G, the protrusions 35f, and the like. Specifically, the lower buffer layer 32 (insulating film overlapping portion 32c) provided on the protrusions 35f of the insulating film 35 is provided spaced apart from the lower buffer layer 32 (groove overlapping portion 32e) provided in the grooves 35G. The lower buffer layer 32 (insulating film overlapping portions 32b, 32d) provided on the electrode side overlapping portions 35e of the insulating film 35 is provided spaced apart from the lower buffer layer 32 (groove overlapping portion 32e) provided in the grooves 35G. As described above, the width (width in the first direction Dx) of the protrusions 35f of the insulating film 35 is formed smaller than the widths (width in the first direction Dx) of the multiple grooves 35G, so that a good discontinuity can be generated between the insulating film overlapping portions 32c and the groove overlapping portions 32e.

[0072] As a result, in adjacent photodiodes PD (for example, photodiodes PD-1 and PD-2), a separated and discontinuous portion is formed between the lower buffer layer 32 provided in the photodiode PD-1 and the lower buffer layer 32 provided in the photodiode PD-2. As a result, the detection device 1 can effectively suppress leakage current flowing between adjacent lower electrodes 23.

[0073] Furthermore, because the insulating film 35 forms the insulating film overlapping portions 32b, 32c, and 32d of the lower buffer layer 32 as high-resistance regions, the spacing between the lower electrodes 23 (or the width of the insulating film 35) can be made smaller than when the electrode overlapping portion 32a of the lower buffer layer 32 and the insulating film overlapping portions 32b, 32c, and 32d are formed with a constant thickness. This makes it possible to increase the area of ​​the effective detection area AA of the detection device 1 and improve detection sensitivity. Alternatively, the area of ​​the lower electrode 23 can be reduced, allowing the detection device 1 to have higher definition.

[0074] Furthermore, in this embodiment, the spacing between the lower electrodes 23 (or the width of the insulating film 35) can be reduced, which makes it possible to suppress delays in the arrival times of carriers (holes and electrons) generated in the active layer 31 between the portion of the photodiode PD that overlaps with the insulating film 35 and the portion of the photodiode PD that does not overlap with the insulating film 35.

[0075] The configurations of the insulating film 35 and the lower buffer layer 32 shown in FIGS. 6 and 7 are merely examples and can be modified as appropriate. For example, the insulating film 35 has two grooves 35G between adjacent lower electrodes 23, but this is not limiting. One or three or more grooves 35G may be provided between adjacent lower electrodes 23. The insulating film 35 may not have the grooves 35G. Even in this case, the thicknesses t2 and t4 of the insulating film overlapping portions 32b and 32d of the lower buffer layer 32 are at least thinner than the thickness t1 of the electrode overlapping portion 32a of the lower buffer layer 32. Therefore, the detection device 1 can suppress leakage current flowing between adjacent lower electrodes 23 even when the insulating film 35 does not have the grooves 35G.

[0076] 6, the electrode side overlapping portions 35e and 35g of the insulating film 35 are provided continuously, surrounding each lower electrode 23. The protruding portion 35f of the insulating film 35 is provided continuously across a plurality of lower electrodes 23. However, this is not limiting, and the electrode side overlapping portions 35e and 35g and the protruding portion 35f may each be formed separately into a plurality of portions.

[0077] 7, the lower buffer layer 32 is provided to overlap the electrode side overlapping portions 35e, 35g and the protruding portion 35f of the insulating film 35. However, without being limited to this, the lower buffer layer 32 does not have to be provided on a part of the insulating film 35. For example, the lower buffer layer 32 may be configured to be provided on the electrode side overlapping portions 35e, 35g of the insulating film 35, but not on the protruding portion 35f (i.e., thickness t3 = 0 nm).

[0078] Second Embodiment Fig. 8 is a plan view schematically showing the positional relationship between the lower electrode and the insulating film in a detection device according to a second embodiment. Fig. 9 is a cross-sectional view taken along line IX-IX' in Fig. 8. In Fig. 8, the insulating film 35 and the wall portion 26 are shown hatched to make the drawing easier to see. In the following description, the same components as those described in the above-mentioned embodiment are designated by the same reference numerals, and redundant description will be omitted.

[0079] As shown in Fig. 8 , in the detection device 1A according to the second embodiment, the insulating film 35 is not provided with a groove 35G, and is provided continuously between adjacent lower electrodes 23. The detection device 1A also has wall portions 26 provided between adjacent lower electrodes 23 and spaced apart from the lower electrodes 23. The wall portions 26 extend along the sides of the lower electrodes 23 and surround the lower electrodes 23 in a plan view. The wall portions 26 are also provided overlapping the insulating film 35 and extending in the extending direction of the insulating film 35. In the example shown in Fig. 8 , two wall portions 26 are provided between adjacent lower electrodes 23.

[0080] 9 , the two wall portions 26 are provided on the insulating film 28 in the same layer as the plurality of lower electrodes 23, and are made of the same material as the plurality of lower electrodes 23. The two wall portions 26 are made of a light-transmitting conductive material such as ITO. The thickness of each wall portion 26 is, for example, not less than 20 nm and not more than 100 nm.

[0081] The insulating film 35 covers the two wall portions 26 and is provided between the adjacent lower electrodes 23. The insulating film 35 is provided along the unevenness formed by the lower electrodes 23 and the two wall portions 26, and is formed with a plurality of unevenness. Specifically, in the photodiode PD-1 and photodiode PD-2 adjacent to each other in the first direction Dx, the insulating film 35 has electrode side overlapping portions 35e, 35g and two convex portions 35h.

[0082] The electrode side overlapping portion 35e is provided overlapping with the side (the right side in FIG. 8) of the lower electrode 23 of the photodiode PD-1 and extends along the side of the lower electrode 23. The electrode side overlapping portion 35g is provided overlapping with the side (the left side in FIG. 8) of the lower electrode 23 of the photodiode PD-2 and extends along the side of the lower electrode 23. The protrusions 35h are provided overlapping with the two wall portions 26, respectively, and extend along the electrode side overlapping portions 35e, 35g.

[0083] Recesses 35i of the insulating film 35 are formed between the electrode side overlapping portion 35g of the insulating film 35 and the protrusion 35h, between two adjacent protrusions 35h, and between the protrusion 35h and the electrode side overlapping portion 35g.

[0084] The lower buffer layer 32 is provided to cover at least a part of the lower electrode 23 of the photodiode PD-1, the lower electrode 23 of the photodiode PD-2, which are adjacent in the first direction Dx, and the insulating film 35. More specifically, the lower buffer layer 32 includes an electrode overlapping portion 32a overlapping the lower electrode 23, insulating film overlapping portions 32b and 32d overlapping with the electrode side overlapping portions 35e and 35g of the insulating film 35, respectively, and a recess overlapping portion 32f provided inside the recess 35i.

[0085] 9, the lower buffer layer 32 is not provided on the two protruding portions 35h. However, the lower buffer layer 32 may be provided on the two protruding portions 35h, similar to the insulating film overlapping portion 32c shown in FIG.

[0086] In this embodiment, the thicknesses t2 and t4 of the insulating film overlapping portions 32b and 32d of the lower buffer layer 32 are also thinner than the thickness t1 of the electrode overlapping portion 32a of the lower buffer layer 32. Furthermore, the thicknesses t2 and t4 of the insulating film overlapping portions 32b and 32d of the lower buffer layer 32 are also thinner than the thickness t5 of the recess overlapping portion 32f of the lower buffer layer 32.

[0087] Furthermore, since the lower buffer layer 32 is not provided on the two convex portions 35h of the insulating film 35, the concave portion overlapping portions 32f provided on each of the two concave portions 35i are provided so as to be spaced apart by the convex portions 35h. Note that, similar to the insulating film overlapping portion 32c shown in Fig. 7, even when the lower buffer layer 32 is provided on the two convex portions 35h, the lower buffer layer 32 provided on the convex portions 35h and the concave portion overlapping portions 32f of the concave portions 35i are provided so as to be spaced apart. In other words, the lower buffer layer 32 is stepped apart by the convex portions 35h and the concave portions 35i.

[0088] With this configuration, also in the second embodiment, the insulating film overlapping portions 32b and 32d of the lower buffer layer 32 located between adjacent lower electrodes 23 have a higher resistance value than the electrode overlapping portion 32a. Also, the lower buffer layer 32 provided on the insulating film 35 is discontinuous at steps formed by the convex portions 35h and the concave portions 35i, etc. As a result, also in this embodiment, it is possible to suppress leakage current flowing between adjacent lower electrodes 23.

[0089] Third Embodiment Fig. 10 is a plan view schematically showing the positional relationship between the lower electrode and the insulating film in a detection device according to a third embodiment, and Fig. 11 is a cross-sectional view taken along the line XI-XI' in Fig. 10.

[0090] 10 and 11 , the detection device 1B according to the third embodiment has an organic insulating film 36 instead of the insulating film 35 made of an inorganic insulating material. The organic insulating film 36 may be made of the same organic insulating material as the insulating film 27, for example. The organic insulating film 36 is provided between the lower electrodes 23 adjacent to each other in the first direction Dx and the second direction Dy, and is provided to cover the peripheral portions of the lower electrodes 23.

[0091] More specifically, the organic insulating film 36 is formed in a lattice pattern with first extension portions 36a and second extension portions 36b intersecting each other. The first extension portions 36a are provided between adjacent lower electrodes 23 in the first direction Dx and extend in the second direction Dy along the sides of the lower electrodes 23. The second extension portions 36b are provided between adjacent lower electrodes 23 in the second direction Dy and extend in the first direction Dx along the sides of the lower electrodes 23.

[0092] The organic insulating film 36 also includes an island-shaped portion 36c that is spaced apart from the first extending portion 36a and the second extending portion 36b. The island-shaped portion 36c is provided in a region that overlaps with the contact hole CH1 (see FIG. 5) at the center of the photodiode PD (lower electrode 23). Note that the island-shaped portion 36c is not limited to being an organic insulating film and may be formed of an inorganic insulating film.

[0093] As shown in FIG. 11 , the height (thickness) of the organic insulating film 36 is greater than the height (film thickness) of the insulating film 35 formed from the inorganic insulating material described above. This separates the lower buffer layers 32 of adjacent photodiodes PD-1 and PD-2, sandwiching the organic insulating film 36 between them. More specifically, the outer edge 32g of the lower buffer layer 32 of the photodiode PD-1 is disposed so as to overlap the inclined surface of the organic insulating film 36. The outer edge 32h of the lower buffer layer 32 of the photodiode PD-2 is disposed so as to overlap the inclined surface of the organic insulating film 36 on the side opposite the outer edge 32g. The lower buffer layer 32 is not provided at least on the top of the organic insulating film 36. In other words, the lower buffer layer 32 is provided within the region surrounded by the first extension 36a and second extension 36b of the organic insulating film 36.

[0094] With this configuration, in the third embodiment, the lower buffer layer 32 is provided for each of the plurality of photodiodes PD (lower electrodes 23) so as to be spaced apart by the organic insulating film 36. As a result, also in this embodiment, the leakage current flowing between adjacent lower electrodes 23 can be suppressed compared to when the lower buffer layer 32 is provided continuously across the plurality of adjacent photodiodes PD.

[0095] 12 is a cross-sectional view schematically showing a detection device according to a fourth embodiment. As shown in FIG. 12, in a detection device 1C according to the fourth embodiment, the insulating film 35 is a laminated film in which a first insulating film 37 and a second insulating film 38 are laminated. The second insulating film 38 is laminated on the first insulating film 37. The first insulating film 37 is formed of, for example, a silicon oxide film, and the second insulating film 38 is formed of a material different from that of the first insulating film 37, for example, a silicon nitride film.

[0096] A groove 35G penetrating the first insulating film 37 and the second insulating film 38 in the thickness direction (third direction Dz) is formed in the insulating film 35. The configuration of the insulating film 35 and the groove 35G in a plan view is the same as that of the first embodiment described above (see FIG. 6 ), and therefore a repeated description will be omitted.

[0097] In this embodiment, the ends of the insulating film 35 (ends in the first direction Dx of the electrode side overlapping portions 35e, 35g that overlap the sides of the lower electrode 23) each have an inverse tapered shape. More specifically, the end 38a of the second insulating film 38 is provided to protrude in the first direction Dx further than the end 37a of the first insulating film 37. The end 38a of the second insulating film 38 is provided in an eave-like shape relative to the end 37a of the first insulating film 37.

[0098] The inner walls of the groove 35G also have an inverse tapered shape. In the groove 35G, the end 38b of the second insulating film 38 protrudes further than the end 37b of the first insulating film 37. In other words, in the groove 35G, the distance between the inner walls of the second insulating film 38 that face each other in the first direction Dx is smaller than the distance between the inner walls of the first insulating film 37 that face each other in the first direction Dx.

[0099] The inverse tapered shape of the insulating film 35 can be formed by utilizing the difference in etching rate between the first insulating film 37 and the second insulating film 38 when patterning the first insulating film 37 and the second insulating film 38 by photolithography and etching. For example, in the example shown in FIG. 12 , the etching rate of the first insulating film 37 is higher than the etching rate of the second insulating film 38.

[0100] In this embodiment, a space is formed at the end of the insulating film 35 (electrode side overlapping portions 35e, 35g) surrounded by the end 38a of the second insulating film 38 that protrudes like an eave, the end 37a of the first insulating film 37, and the lower electrode 23. The electrode overlapping portion 32a of the lower buffer layer 32 is also provided so as to extend into the space surrounded by the end 37a of the first insulating film 37, the end 38a of the second insulating film 38, and the lower electrode 23. This makes it easier for a step to occur between the electrode overlapping portion 32a of the lower buffer layer 32 and the insulating film overlapping portion 32b.

[0101] In addition, in the groove 35G, a space is formed that is surrounded by the end 38b of the second insulating film 38, the end 37b of the first insulating film 37, and the insulating film 28. The groove overlapping portion 32e of the lower buffer layer 32 is also provided inside the space that is surrounded by the end 38b of the second insulating film 38, the end 37b of the first insulating film 37, and the insulating film 28.

[0102] As a result, the groove 35G is formed straight, and the space of the groove 35G is larger than in a configuration that is not formed in an inverted tapered shape (see FIG. 7 ). As a result, a step is likely to occur between the groove overlapping portion 32e of the lower buffer layer 32 and the insulating film overlapping portion 32b. Also in this embodiment, the thicknesses t2 and t4 of the insulating film overlapping portions 32b and 32d of the lower buffer layer 32 are thinner than the thickness t1 of the electrode overlapping portion 32a of the lower buffer layer 32. Also, the thicknesses t2 and t4 of the insulating film overlapping portions 32b and 32d of the lower buffer layer 32 are thinner than the thickness t5 of the groove overlapping portion 32e of the lower buffer layer 32.

[0103] In this embodiment, the lower buffer layer 32 is not provided on the second insulating film 38 of the convex portion 35f. However, similar to the insulating film overlapping portion 32c shown in FIG. 7, the lower buffer layer 32 may be provided on the second insulating film 38 of the convex portion 35f. Even in this case, since the groove portion 35G is formed in an inverse tapered shape, the lower buffer layer 32 provided on the convex portion 35f and the groove overlapping portion 32e of the groove portion 35G are provided at a distance from each other. That is, the lower buffer layer 32 is stepped at the convex portion 35f and the groove portion 35G.

[0104] 13 is a cross-sectional view schematically illustrating a detection device according to a modification of the fourth embodiment. As shown in Fig. 13, the detection device 1D according to the modification of the fourth embodiment differs from the detection device 1C according to the fourth embodiment (see Fig. 12) in that the groove 35G is not provided.

[0105] 13 , in a detection device 1D according to a modification of the fourth embodiment, the insulating film 35 (first insulating film 37 and second insulating film 38) is provided continuously between adjacent lower electrodes 23. Furthermore, the ends of the insulating film 35 (electrode side overlapping portions 35 e, 35 g) are each formed in an inverse tapered shape. More specifically, the end 38 a of the second insulating film 38 is formed in an inverse tapered shape, projecting further in the first direction Dx than the end 37 a of the first insulating film 37.

[0106] This facilitates step separation and spacing between at least the electrode overlapping portion 32a of the lower buffer layer 32 and the insulating film overlapping portions 32b, 32d. Also in this modification, the thicknesses t2, t4 of the insulating film overlapping portions 32b, 32d of the lower buffer layer 32 are thinner than the thickness t1 of the electrode overlapping portion 32a of the lower buffer layer 32. Therefore, even in a configuration in which the groove 35G is not provided in this modification, it is possible to suppress leakage current flowing between adjacent lower electrodes 23.

[0107] Although preferred embodiments of the present invention have been described above, the present invention is not limited to such embodiments. The contents disclosed in the embodiments are merely examples, and various modifications are possible without departing from the spirit of the present invention. Appropriate modifications made without departing from the spirit of the present invention naturally fall within the technical scope of the present invention. At least one of various omissions, substitutions, and modifications of components can be made without departing from the gist of each of the above-described embodiments and modifications.

[0108] 1, 1A, 1B, 1C, 1D Detector 10 Sensor section 21 Sensor substrate 23 Lower electrode 24 Upper electrode 26 Wall section 27, 28 Insulating film 31 Active layer 32 Lower buffer layer 32a Electrode overlapping section 32b, 32c, 32d Insulating film overlapping section 33 Upper buffer layer 35 Insulating film 35a, 36a First extending section 35b, 36b Second extending section 35c, 36c Island-shaped section 35e, 35g Electrode side overlapping section 35f, 35h Convex section 35i Concave section 36 Organic insulating film 37 First insulating film 38 Second insulating film 37a, 38a End section 90 Sealing film PD, PD-1, PD-2 Photodiode AA Detection area GA Peripheral area

Claims

1. A detection device comprising: a substrate; a plurality of photodiodes stacked on the substrate in the following order: a lower electrode, a lower buffer layer, an active layer, an upper buffer layer, and an upper electrode; and an insulating film provided between adjacent lower electrodes, wherein the lower buffer layer includes an electrode overlapping portion that overlaps the lower electrode and an insulating film overlapping portion that overlaps at least a portion of the insulating film, and the insulating film overlapping portion of the lower buffer layer has a thickness thinner than the thickness of the electrode overlapping portion of the lower buffer layer.

2. The detection device according to claim 1, wherein the insulating film has grooves extending along the sides of the plurality of lower electrodes between adjacent plurality of lower electrodes.

3. The detection device according to claim 1, wherein the insulating film has a plurality of grooves extending along the sides of a plurality of the lower electrodes between adjacent plurality of the lower electrodes, and protrusions located between the plurality of the grooves, and the lower buffer layer provided on the protrusions is provided at a distance from the lower buffer layer provided in the grooves.

4. The detection device according to claim 1, further comprising a wall portion formed of the same material as the lower electrodes and spaced apart from the lower electrodes, between the adjacent lower electrodes, and the insulating film covering the wall portion and provided between the adjacent lower electrodes.

5. The detection device according to claim 1, wherein the insulating film is made of an organic insulating material.

6. The detection device according to claim 5, wherein the lower buffer layers of adjacent photodiodes are separated by the insulating film.

7. The detection device according to claim 1, wherein the end of the insulating film has an inverse tapered shape.

8. The detection device according to claim 1, wherein the insulating film comprises a first insulating film and a second insulating film provided on the first insulating film, and an end of the second insulating film is provided to protrude beyond an end of the first insulating film.

9. The detection device according to claim 8, wherein the first insulating film is a silicon oxide film, and the second insulating film is a silicon nitride film.

10. The detection device according to claim 3, wherein the thickness of the insulating film overlapping portion of the lower buffer layer is thinner than the thickness of the lower buffer layer provided in the groove portion.

11. The detection device according to claim 1, wherein the thickness of the insulating film provided between adjacent lower electrodes is 20 nm or more and 200 nm or less.

12. The detection device according to claim 4, wherein the thickness of the wall portion is 20 nm or more and 100 nm or less.

13. The detection device according to claim 3, wherein the width of the convex portion is smaller than the width of the plurality of groove portions and smaller than the interval between the plurality of adjacent lower electrodes.

14. The detection device according to claim 1, wherein the photodiode is an OPD (organic photodiode).