Photodetector

Abstract

To provide a photodetector that can achieve high sensitivity. [Solution] According to the embodiment, the photodetector includes a first electrode, a second electrode, and a laminate. At least a portion of the laminate is provided between the first electrode and the second electrode. The laminate includes a photoelectric conversion layer along a first plane and an optical member. The photoelectric conversion layer is located between the first electrode and the second electrode in a first direction intersecting the first plane. The direction from the photoelectric conversion layer to the optical member is along the first direction. The optical member includes a first optical layer. The first optical layer includes a plurality of first regions aligned along the first plane and a first intermediate region between the plurality of first regions. The first region refractive index of the plurality of first regions is different from the first intermediate region refractive index of the first intermediate region.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to photodetectors. [Background technology]

[0002] For example, there is a photodetector that includes a photoelectric conversion layer. In a photodetector, it is desirable to be able to detect the target light with high sensitivity. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 6001063 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The embodiment provides a photodetector that can achieve high sensitivity. [Means for solving the problem]

[0005] According to one embodiment, the photodetector includes a first electrode, a second electrode, and a laminate. At least a portion of the laminate is provided between the first electrode and the second electrode. The laminate includes a photoelectric conversion layer along a first plane and an optical member. The photoelectric conversion layer is located between the first electrode and the second electrode in a first direction intersecting the first plane. The direction from the photoelectric conversion layer to the optical member is along the first direction. The optical member includes a first optical layer. The first optical layer includes a plurality of first regions aligned along the first plane and a first intermediate region between the plurality of first regions. The first region refractive index of the plurality of first regions is different from the first intermediate region refractive index of the first intermediate region. [Brief explanation of the drawing]

[0006] [Figure 1] Figures 1(a) and 1(b) are schematic diagrams illustrating a photodetector according to the first embodiment. [Figure 2] FIG. 2 is a schematic plan view illustrating a part of the photodetector according to the first embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view illustrating the photodetector according to the first embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view illustrating the photodetector according to the second embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view illustrating the photodetector according to the second embodiment. [Figure 6] FIG. 6 is a schematic cross-sectional view illustrating the photodetector according to the second embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view illustrating the photodetector according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationships between the thickness and width of each part, the ratios of the sizes between parts, etc. are not necessarily the same as those in reality. Even when representing the same part, the dimensions and ratios may be represented differently in the drawings. In the specification of the present application and each figure, elements similar to those described above with respect to the previously presented figures are denoted by the same reference numerals, and detailed descriptions thereof are omitted as appropriate.

[0008] (First Embodiment) FIGS. 1(a) and 1(b) are schematic views illustrating the photodetector according to the first embodiment. FIG. 1(b) is a plan view. FIG. 1(a) is a cross-sectional view taken along line A1 - A2 of FIG. 1(b). FIG. 2 is a schematic plan view illustrating a part of the photodetector according to the first embodiment. As shown in FIG. 1(a), the photodetector 110 according to the embodiment includes a first electrode 51, a second electrode 52, and a laminate 15.

[0009] At least a part of the laminate 15 is provided between the first electrode 51 and the second electrode 52. The laminate 15 includes a photoelectric conversion layer 10 and an optical member 20. The laminate 15 may include another layer (for example, the first semiconductor layer 31, etc.). Examples of other layers will be described later.

[0010] The photoelectric conversion layer 10 is along the first plane PL1. One direction along the first plane PL1 is the X-axis direction. Along the first plane PL1, the direction perpendicular to the X-axis direction is the Y-axis direction. The direction perpendicular to the X-axis direction and the Y-axis direction is the Z-axis direction.

[0011] The optical member 20 extends along the first plane PL1. The photoelectric conversion layer 10 extends along the first plane PL1.

[0012] The photoelectric conversion layer 10 is between the first electrode 51 and the second electrode 52 in the first direction D1. The first direction D1 intersects the first plane PL1. The first direction D1 may be, for example, the Z-axis direction.

[0013] The direction from the photoelectric conversion layer 10 to the optical member 20 is along the first direction D1. The optical member 20 is laminated with the photoelectric conversion layer 10.

[0014] The optical member 20 includes a first optical layer 21. The first optical layer 21 includes a plurality of first regions 21a and a first intermediate region 21b. As shown in FIG. 2, the plurality of first regions 21a are arranged along the first plane PL1. The first intermediate region 21b is between the plurality of first regions 21a.

[0015] In this example, a plurality of island-shaped first regions 21a are provided. The first intermediate region 21b is continuous.

[0016] In an embodiment, at least a part of the plurality of first regions 21a may be continuous. For example, in one direction along the first plane PL1 (for example, the second direction D2), one first region 21a and another first region 21a may be arranged side by side. For example, the first intermediate region 21b may be island-shaped.

[0017] The refractive index of the multiple first regions 21a is different from the refractive index of the first intermediate region 21b. The multiple first regions 21a and the first intermediate region 21b may be crystals. The multiple first regions 21a and the first intermediate region 21b may contain semiconductors. The first optical layer 21 functions, for example, as a photonic crystal layer.

[0018] For example, the first electrode 51 is electrically connected to the photoelectric conversion layer 10. The second electrode 52 is electrically connected to the optical member 20. The electrical signal generated between the first electrode 51 and the second electrode 52 is configured to change in response to the light 81 (detection target light) incident on the optical member 20. The light 81 may be, for example, laser light.

[0019] For example, the optical member 20 includes a light incident surface 20F. Light 81 is incident on the optical member 20 from the light incident surface 20F. For example, the light 81 may be incident substantially perpendicular to the light incident surface 20F. High incidence efficiency can be obtained.

[0020] Light 81 incident on the optical member 20 propagates along the first plane PL1 within the optical member 20. The light 81 spreads along the first plane PL1, and the spread light 81 is incident on the photoelectric conversion layer 10, where mobile carriers are generated. The light 81 can be detected by extracting the carriers via the first electrode 51 and the second electrode 52. A bias voltage may be applied to the first electrode 51 and the second electrode 52.

[0021] For example, the electric field of light 81 incident on the light incident surface 20F along a first direction D1 includes a component perpendicular to the first direction D1. Light 81 incident on the optical member 20 propagates along a first plane PL1. The electric field of the propagating light 81 includes a component perpendicular to the first plane PL1. Such light 81 is efficiently absorbed in the photoelectric conversion layer 10, generating carriers. Efficient photoelectric conversion is obtained. For example, light 81 can be detected with high sensitivity. According to this embodiment, a photodetector with high sensitivity can be provided.

[0022] In an embodiment, the photoelectric conversion layer 10 may include a plurality of first compound layers 11 and a plurality of second compound layers 12. One of the plurality of first compound layers 11 is located between one of the plurality of second compound layers 12 and another one of the plurality of second compound layers 12 in the first direction D1. One of the plurality of second compound layers 12 is located between one of the plurality of first compound layers 11 and another one of the plurality of first compound layers 11 in the first direction D1. For example, the first compound layers 11 and the second compound layers 12 may be arranged alternately in the first direction D1.

[0023] The plurality of first compound layers 11 include, for example, In z1 Ga 1-z1 As (0 < z1 < 1). The plurality of second compound layers 12 include, for example, In y1 Al 1-y1 As (0 < y1 < 1). These compound layers are semiconductor crystal layers.

[0024] The photoelectric conversion layer 10 includes, for example, a quantum cascade active layer. In the photoelectric conversion layer 10, sub-band transitions of carriers occur, and efficient photoelectric conversion can be obtained.

[0025] In an optical embodiment, the light 81 may be, for example, infrared light. The wavelength of the light 81 may be, for example, 3 μm or more and 16 μm or less. For example, the detection target substance may be a gas or the like. Changes in the light 81 based on absorption in the gas may be detected by the photodetector 110.

[0026] In an embodiment, the plurality of first regions 21a may include In x1 Ga 1-x1 As (0 < x1 < 1). The first intermediate region 21b may include InP. These regions may be semiconductor crystals, and a large refractive index difference can be stably obtained.

[0027] Thus, the optical member 20 includes a semiconductor. Thereby, an electric field applied between the first electrode 51 and the second electrode 52 is applied to the photoelectric conversion layer 10 through the optical member 20, and carriers can be efficiently extracted.

[0028] As shown in Figure 1(a), the first optical layer 21 may further include a first continuous region 21c. The first continuous region 21c extends along the first plane PL1. The first continuous region 21c lies between the photoelectric conversion layer 10 and the plurality of first regions 21a, and between the photoelectric conversion layer 10 and the first intermediate region 21b. The refractive index of the first continuous region 21c may be the same as the refractive index of the plurality of first regions 21a. For example, the material of the first continuous region 21c may be substantially the same as the material of the plurality of first regions 21a.

[0029] As shown in Figure 1(a), the laminate may include 15 and a first semiconductor layer 31. The first semiconductor layer 31 includes a first partial region 31p and a second partial region 31q. The direction from the first partial region 31p to the second partial region 31q intersects with the first direction D1. The photoelectric conversion layer 10 is located between the first partial region 31p and the optical member 20 in the first direction D1. The photoelectric conversion layer 10 does not overlap with the second partial region 31q in the first direction D1. The first partial region 31p may be, for example, at least a part of a mesa region. The photoelectric conversion layer 10 may be included in the mesa region. The optical member 20 may be included in the mesa region. The first semiconductor layer 31 may include, for example, a substrate. The first semiconductor layer 31 may include, for example, InP.

[0030] As shown in Figures 1(a) and 1(b), the second electrode 52 may include a linear region 52L. The linear region 52L extends along the first plane PL1. The linear region 52L is provided along the light incident surface 20F. The laminate 15 includes an overlapping region 15p and a non-overlapping region 15q. The overlapping region 15p overlaps with the linear region 52L in the first direction D1. The non-overlapping region 15q does not overlap with the linear region 52L in the first direction D1. The non-overlapping region 15q is not covered by the linear region 52L.

[0031] Light 81 may be attenuated in the linear region 52L. Light 81 may be reflected in the linear region 52L. Light 81 does not need to substantially pass through the linear region 52L. Light 81 may be incident on the non-superposition region 15q and then incident on the photoelectric conversion layer 10. The linear region 52L allows an electric field to be effectively applied over a wide area, and carriers can be efficiently extracted.

[0032] Multiple linear regions 52L may be provided. The direction in which one of the multiple linear regions 52L extends may intersect with the direction in which another of the multiple linear regions 52L extends. One of the multiple linear regions 52L may extend along a second direction D2. Another of the multiple linear regions 52L may extend along a third direction D3. The third direction D3 intersects a plane containing the first direction D1 and the second direction D2. The second direction D2 may be in the X-axis direction. The third direction D3 may be in the Y-axis direction.

[0033] As shown in Figure 1(a), the photodetector 110 may further include a reflective member 55. The photoelectric conversion layer 10 includes a photoelectric conversion layer side surface 10s. The photoelectric conversion layer side surface 10s intersects with the first plane PL1. At least a portion of the reflective member 55 faces the photoelectric conversion layer side surface 10s. The reflective member 55 may be continuous with the second electrode 52. The reflective member 55 may be formed from a film that becomes the second electrode 52. The reflective member 55 may contain the same material as the second electrode 52. The reflective member 55 may be conductive.

[0034] The photodetector 110 may further include an insulating member 41. At least a portion of the insulating member 41 is provided between the photoelectric conversion layer 10 and the reflective member 55.

[0035] The optical member 20 includes an optical member side surface 20s. The optical member side surface 20s intersects with the first plane PL1. A portion of the reflective member 55 may face the optical member side surface 20s. The insulating member 41 is provided between the photoelectric conversion layer 10 and the reflective member 55.

[0036] Light 81 incident on the optical element 20 can be efficiently incident on the photoelectric conversion layer 10. The reflective element 55 provides higher sensitivity.

[0037] The first pitch p1 in the first plane PL1 of the multiple first regions 21a may be, for example, 1000 nm or more and 5000 nm or less. The direction of propagation of light 81 can be efficiently converted. The first pitch p1 may be, for example, a length along the second direction D2.

[0038] The length (thickness) of one of the multiple first regions 21a along the second direction D2 may be, for example, between 0.1 μm and 4.5 μm. The distance along the second direction D2 between one of the multiple first regions 21a and another of the multiple first regions 21a may be between 0.2 μm and 4.5 μm. One of the multiple first regions 21a is adjacent to another of the multiple first regions 21a.

[0039] In the example shown in Figure 2, the planar shape of each of the multiple first regions 21a is circular. The circular shape includes both circular and oblate circles. The planar shape of each of the multiple first regions 21a may be polygonal. The number of corners in the polygon may be four or more. The number may also be five or more. The corners of the polygon may be curved.

[0040] As shown in Figure 1(a), the optical member 20 may include a second semiconductor layer 32. The first optical layer 21 is located between the photoelectric conversion layer 10 and the second semiconductor layer 32. The second semiconductor layer 32 may contain the same material as the first intermediate region 21b.

[0041] Figure 3 is a schematic cross-sectional view illustrating a photodetector according to the first embodiment. As shown in Figure 3, in the photodetector 111 according to this embodiment, the optical element side surface 20s is tapered. The configuration of the photodetector 111, aside from this, may be the same as that of the photodetector 110.

[0042] In the photodetector 111, the side surface 20s of the optical element is inclined with respect to the first plane PL1. The photodetector 111 includes a reflective member 55. At least a portion of the reflective member 55 faces the side surface 20s of the optical element. The tapered side surface allows light 81 to be efficiently incident on the photoelectric conversion layer 10. This enables efficient detection.

[0043] In the photodetector 111, the photoelectric conversion layer 10 may include a photoelectric conversion layer side surface 10s that is inclined with respect to the first plane PL1. At least a portion of the reflective member 55 faces the photoelectric conversion layer side surface 10s. The inclination of the photoelectric conversion layer side surface 10s with respect to the first plane PL1 makes it easier for the direction of propagation of some of the light 81 to change. The light 81 is efficiently converted into an electrical signal.

[0044] At least a portion of the insulating member 41 may be provided between the photoelectric conversion layer 10 and the reflective member 55. At least a portion of the insulating member 41 may be provided between the optical member 20 and the reflective member 55.

[0045] The first angle θ1 between the first plane PL1 and the photoelectric conversion layer side surface 10s can be, for example, between 60 and 89 degrees. The second angle θ2 between the first plane PL1 and the optical element side surface 20s can be, for example, between 60 and 89 degrees. The first angle θ1 can be smaller than the second angle θ2. Higher efficiency is easier to obtain.

[0046] (Second Embodiment) Figure 4 is a schematic cross-sectional view illustrating a photodetector according to the second embodiment. As shown in Figure 4, in the photodetector 120 according to this embodiment, the optical member 20 includes a plurality of optical layers. The configuration of the photodetector 120, excluding this, may be the same as the configuration of the photodetector 110 or the photodetector 111.

[0047] In the photodetector 120, the optical member 20 further includes a second optical layer 22 in addition to the first optical layer 21. The second optical layer 22 includes a plurality of second regions 22a and a second intermediate region 22b. The plurality of second regions 22a are aligned along the first plane PL1. The second intermediate region 22b lies between the plurality of second regions 22a. The second region refractive index of the plurality of second regions 22a is different from the second intermediate region refractive index of the second intermediate region 22b. The direction from one of the plurality of first regions 21a to one of the plurality of second regions 22a is along the first direction D1.

[0048] The second optical layer 22 functions as a photonic crystal layer. By providing the second optical layer 22 in addition to the first optical layer 21, light 81 can propagate more effectively in the direction along the first plane PL1. High-efficiency photoelectric conversion is achieved in the photoelectric conversion layer 10.

[0049] The shape of each of the multiple second regions 22a may be the same as the shape of each of the multiple first regions 21a. The pitch of the multiple second regions 22a may be the same as the first pitch p1 of the multiple first regions 21a. The multiple second regions 22a overlap with the multiple first regions 21a in the first direction D1. The second intermediate region 22b overlaps with the first intermediate region 21b in the first direction D1.

[0050] As shown in Figure 4, the optical member 20 may include a first interlayer region 21M. The first interlayer region 21M is located between the first optical layer 21 and the second optical layer 22. For example, the refractive index of the first interlayer region 21M is different from the refractive index of the second region of the multiple second regions 22a.

[0051] The refractive index differs between multiple first regions 21a and first interlayer region 21M. The refractive index also differs between multiple second regions 22a and first interlayer region 21M. Due to the difference in refractive index, the propagation direction of light 81 is efficiently changed.

[0052] For example, in the first optical layer 21, the difference in refractive index at the interface between multiple first regions 21a and first intermediate region 21b is utilized. In the second optical layer 22, the difference in refractive index at the interface between multiple second regions 22a and second intermediate region 22b is utilized. These interfaces intersect with the first plane PL1.

[0053] The difference in refractive index at the interface between multiple first regions 21a and the first interlayer region 21M is utilized. The difference in refractive index at the interface between multiple second regions 22a and the first interlayer region 21M is utilized. These interfaces are aligned with the first plane PL1. The difference in refractive index at interfaces intersecting the first plane PL1 and interfaces aligned with the first plane PL1 is utilized. Higher sensitivity can be obtained.

[0054] The refractive index of the first interlayer region 21M in the first interlayer region may be the same as the refractive index of the first intermediate region 21b in the first intermediate region. The refractive index of the plurality of second regions 22a in the second region may be the same as the refractive index of the plurality of first regions 21a in the first region. The refractive index of the second intermediate region 22b in the second intermediate region may be the same as the refractive index of the first intermediate region 21b in the first intermediate region. The first interlayer region 21M may be provided between the first intermediate region 21b and the second intermediate region 22b. The boundaries of these regions may be clear or unclear.

[0055] The plurality of second regions 22a may contain In x2 Ga 1-x2 As (0 < x2 < 1). The second intermediate region 22b may contain InP. The composition ratio x2 may be the same as or different from the composition ratio x1.

[0056] Let the distance between the first center in one first direction D1 of the plurality of first regions 21a and the second center in one first direction D1 of the plurality of second regions 22a be the first distance d1. The first pitch p1 in the first plane PL1 of the plurality of first regions 21a may be 0.5 times or more and 7 times or less the first distance d1. Higher sensitivity can be obtained.

[0057] In an embodiment, the number of the plurality of optical layers may be 3 or more. For example, the optical member 20 may further include a third optical layer 23. The optical member 20 may further include a second interlayer region 22M. The second interlayer region 22M is between the second optical layer 22 and the third optical layer 23.

[0058] The third optical layer 23 includes a plurality of third regions 23a and a third intermediate region 23b. The plurality of third regions 23a are arranged along the first plane PL1. The third intermediate region 23b is between the plurality of third regions 23a. The refractive index of the plurality of third regions 23a in the third region is different from the refractive index of the third intermediate region 23b in the third intermediate region. The direction from one of the plurality of second regions 22a to one of the plurality of third regions 23a is along the first direction D1. The plurality of third regions 23a overlap with the plurality of second regions 22a in the first direction D1. The third intermediate region 23b overlaps with the second intermediate region 22b in the first direction D1.

[0059] The third optical layer 23 functions as a photonic crystal layer. More effectively, light 81 can propagate in the direction along the first plane PL1. In the photoelectric conversion layer 10, more efficient photoelectric conversion can be obtained.

[0060] The refractive index of the second interlayer region 22M in the second interlayer region is different from the refractive index of the plurality of third regions 23a in the third region. At the interface between the plurality of third regions 23a and the second interlayer region 22M, the difference in refractive index is utilized. The refractive index of the second interlayer region 22M in the second interlayer region is different from the refractive index of the plurality of second regions 22a in the second region. At the interface between the plurality of second regions 22a and the second interlayer region 22M, the difference in refractive index is utilized. Efficient detection is possible. High-sensitivity detection is possible.

[0061] The refractive index of the second interlayer region 22M in the second interlayer region may be the same as the refractive index of the second intermediate region 22b in the second intermediate region.

[0062] The plurality of third regions 23a may contain In x3 Ga 1-x3 As (0 < x3 < 1). The third intermediate region 23b may contain InP. The composition ratio x3 may be the same as or different from the composition ratio x1. The composition ratio x3 may be the same as or different from the composition ratio x2.

[0063] Let the distance between the second center in one first direction D1 of the plurality of second regions 22a and the third center in one first direction D1 of the plurality of third regions 23a be the second distance d2. The first pitch p1 in the first plane PL1 of the plurality of first regions 21a may be 0.5 times or more and 7 times or less of the second distance d2. Higher sensitivity can be obtained.

[0064] In the embodiment, by providing a plurality of optical layers, the propagation direction of light 81 can be efficiently converted in the direction along the first direction D1. The electric field direction of light 81 can be efficiently converted in the direction intersecting the first plane PL1. For example, the directivity (or the controllability of directivity) of the detection characteristics of the incident light 81 can be improved.

[0065] The plurality of first regions 21a may be arranged two-dimensionally along the first plane PL1. The plurality of second regions 22a may be arranged two-dimensionally along the first plane PL1. The plurality of third regions 23a may be arranged two-dimensionally along the first plane PL1.

[0066] FIG. 5 is a schematic cross-sectional view illustrating a photodetector according to the second embodiment. As shown in FIG. 5, in the photodetector 121 according to the embodiment, the configuration of the optical member 20 is different from that in the photodetector 120. The configuration of the photodetector 121 excluding this may be the same as that of the photodetector 120.

[0067] In the photodetector 121, the first intermediate region 21b contains a gas. The substrate may contain air or the like. The plurality of first regions 21a may contain, for example, In x1 Ga 1-x1 As (0 < x1 < 1). A large refractive index difference is obtained between the plurality of first regions 21a and the first intermediate region 21b.

[0068] The second intermediate region 22b may contain a gas. The plurality of second regions 22a may contain, for example, In x2 Ga 1-x2 As (0 < x2 < 1). A large refractive index difference is obtained between the plurality of second regions 22a and the second intermediate region 22b. The third intermediate region 23b may contain a gas. The plurality of third regions 23a may contain, for example, In x3 Ga 1-x3 As (0 < x3 < 1). A large refractive index difference is obtained between the plurality of third regions 23a and the third intermediate region 23b.

[0069] The second electrode 52 may include a linear region 52L extending along the first plane PL1. The laminate 15 includes an overlapping region 15p and a non-overlapping region 15q. The overlapping region 15p overlaps with the linear region 52L in the first direction D1. The non-overlapping region 15q does not overlap with the linear region 52L in the first direction D1. In the photodetector 121, the first intermediate region 21b in the non-overlapping region 15q contains a gas (e.g., air). The second intermediate region 22b in the non-overlapping region 15q contains a gas. The third intermediate region 23b in the non-overlapping region 15q contains a gas.

[0070] The first intermediate region 21b in the superimposed region 15p contains a semiconductor crystal. The second intermediate region 22b in the superimposed region 15p contains a semiconductor crystal. The third intermediate region 23b in the superimposed region 15p contains a semiconductor crystal. The semiconductor crystal contains, for example, InP.

[0071] Figure 6 is a schematic cross-sectional view illustrating a photodetector according to the second embodiment. As shown in Figure 6, in the photodetector 122 according to this embodiment, the configuration of the optical element 20 is different from that of the photodetector 121. The rest of the configuration of the photodetector 122 may be the same as that of the photodetector 120.

[0072] In the photodetector 122, the first optical layer 21 further includes a first intermediate layer 21x. The first intermediate layer 21x is provided between a plurality of first regions 21a and a first interlayer region 21M. The second optical layer 22 may further include a second intermediate layer 22x. The second intermediate layer 22x is provided between a plurality of second regions 22a and a second interlayer region 22M.

[0073] The third optical layer 23 may further include a third intermediate layer 23x. Multiple third regions 23a are provided between the second interlayer region 22M and the third interlayer region 23M.

[0074] The first intermediate layer 21x, the second intermediate layer 22x, and the third intermediate layer 23x are, for example, Inα1Al 1-α1It may include As (0 < α1 < 1). The plurality of first regions 21a, the plurality of second regions 22a, and the plurality of third regions 23a may include, for example, In x1 Ga 1-x1 It may include As (0 < x1 < 1). The first interlayer region 21M, the second interlayer region 22M, and the third interlayer region 23M include, for example, InP.

[0075] For example, characteristic degradation due to the difference in lattice length between the plurality of first regions 21a and the first interlayer region 21M is suppressed. For example, the adverse effect due to strain is mitigated. For example, characteristic degradation due to the difference in lattice length between the plurality of second regions 22a and the second interlayer region 22M is suppressed. For example, the adverse effect due to strain is mitigated.

[0076] FIG. 7 is a schematic cross-sectional view illustrating a photodetector according to the second embodiment. As shown in FIG. 7, in the photodetector 123 according to the embodiment, the configuration of the optical member 20 is different from that in the photodetector 120. The configuration of the photodetector 123 except this may be the same as the configuration of the photodetector 120.

[0077] In the photodetector 123, the side surface 20s of the optical member is inclined with respect to the first plane PL1. The photodetector 123 includes a reflection member 55. At least a part of the reflection member 55 faces the side surface 20s of the optical member. Due to the tapered side surface, light 81 can be efficiently incident on the photoelectric conversion layer 10. Efficient detection is possible.

[0078] In the photodetector 123, the photoelectric conversion layer 10 may include a side surface 10s of the photoelectric conversion layer that is inclined with respect to the first plane PL1. At least a part of the reflection member 55 faces the side surface 10s of the photoelectric conversion layer. Since the side surface 10s of the photoelectric conversion layer is inclined with respect to the first plane PL1, the traveling direction of a part of the light 81 changes. The light 81 is efficiently converted into an electric signal.

[0079] At least a part of the insulating member 41 may be provided between the photoelectric conversion layer 10 and the reflection member 55. At least a part of the insulating member 41 may be provided between the optical member 20 and the reflection member 55.

[0080] The first angle θ1 between the first plane PL1 and the photoelectric conversion layer side surface 10s can be, for example, between 60 and 89 degrees. The second angle θ2 between the first plane PL1 and the optical element side surface 20s can be, for example, between 60 and 89 degrees. The first angle θ1 can be smaller than the second angle θ2. Higher efficiency is easier to obtain.

[0081] For example, multiple first regions 21a can be obtained by forming a film that will become multiple first regions 21a and removing a part of that film. The first intermediate region 21b can be obtained by filling the removed region with a material that will become the first intermediate region 21b. For example, the formation of a first film that will become multiple first regions 21a and the formation of a second film that will become the first interlayer region 21M may be repeated. After that, a part of multiple sets of structures including the first film and the second film may be removed all at once. In the removal, for example, dry etching may be performed. A highly accurate shape can be obtained.

[0082] The embodiments may include the following technical proposals. (Technical proposal 1) First electrode and, The second electrode and, A laminate, wherein at least a portion of the laminate is provided between the first electrode and the second electrode, Equipped with, The laminated body is A photoelectric conversion layer along the first plane, Optical components and Includes, The photoelectric conversion layer is located between the first electrode and the second electrode in a first direction intersecting the first plane, The direction from the photoelectric conversion layer to the optical member is along the first direction, The optical member includes a first optical layer, The first optical layer is A plurality of first regions arranged along the first plane, A first intermediate region between the plurality of first regions, Includes, A photodetector wherein the refractive index of the first region of the plurality of first regions is different from the refractive index of the first intermediate region of the first intermediate region.

[0083] (Technical proposal 2) The optical member further includes a second optical layer, The preceding second optical layer is Multiple second regions arranged along the first plane, A second intermediate region between the plurality of second regions, Includes, The refractive index of the plurality of second regions differs from the refractive index of the second intermediate region of the second intermediate region. The photodetector according to Technical Proposal 1, wherein the direction from one of the plurality of first regions to one of the plurality of second regions is along the first direction.

[0084] (Technical proposal 3) The optical member further includes a first interlayer region between the first optical layer and the second optical layer, The photodetector according to Technical Proposal 2, wherein the refractive index of the first interlayer region is different from the refractive index of the second region.

[0085] (Technical proposal 4) The refractive index of the second region is the same as the refractive index of the first region. The photodetector according to Technical Proposal 2 or 3, wherein the second intermediate region refractive index is the same as the first intermediate region refractive index.

[0086] (Technical proposal 5) The photodetector according to any one of Technical Proposals 2 to 4, wherein the first pitch of the plurality of first regions in the first plane is 0.5 to 7 times the first distance between the first center of the plurality of first regions in one of the first directions and the second center of the plurality of second regions in one of the first directions.

[0087] (Technical proposal 6) The optical member further includes a third optical layer and a second interlayer region between the second optical layer and the third optical layer, The third optical layer is, Multiple third regions arranged along the first plane, A third intermediate region between the plurality of third regions, Includes, The refractive indices of the plurality of third regions differ from the refractive indices of the third intermediate region, The direction from one of the plurality of second regions to one of the plurality of third regions is along the first direction, A photodetector according to any one of Technical Proposals 2 to 4, wherein the refractive index of the second interlayer region is different from the refractive index of the third region.

[0088] (Technical proposal 7) The photodetector according to Technical Proposal 6, wherein the first pitch in the first plane of the plurality of first regions is 0.5 to 7 times the second distance between the second center in one of the first directions of the plurality of second regions and the third center in one of the first directions of the plurality of third regions.

[0089] (Technical proposal 8) The first optical layer further includes a first continuous region extending along the first plane, The first continuous region is located between the photoelectric conversion layer and the plurality of first regions, and between the photoelectric conversion layer and the first intermediate region. A photodetector according to any one of Technical Proposals 1 to 7, wherein the refractive index of the first continuous region is the same as the refractive index of the first region.

[0090] (Technical proposal 9) The laminate includes a first semiconductor layer, The first semiconductor layer includes a first partial region and a second partial region. The direction from the first subregion to the second subregion intersects the first direction, The photoelectric conversion layer is located between the first partial region and the optical member in the first direction. The photoelectric conversion layer is a photodetector according to any one of the technical proposals 1 to 8, wherein the photoelectric conversion layer does not overlap with the second subregion in the first direction.

[0091] (Technical proposal 10) The photoelectric conversion layer includes a quantum cascade active layer, and is the photodetector according to any one of Technical Solutions 1 to 9.

[0092] (Technical Solution 11) In the photoelectric conversion layer, the photodetector according to any one of Technical Solutions 1 to 10, in which sub-band transitions of carriers occur.

[0093] (Technical Solution 12) The photoelectric conversion layer includes a plurality of first compound layers and a plurality of second compound layers, One of the plurality of first compound layers is between one of the plurality of second compound layers and another one of the plurality of second compound layers, One of the plurality of second compound layers is between one of the plurality of first compound layers and another one of the plurality of first compound layers, The plurality of first compound layers include In z1 Ga 1-z1 As (0 < z1 < 1), The plurality of second compound layers include In y1 Al 1-y1 As (0 < y1 < 1), and is the photodetector according to any one of Technical Solutions 1 to 11.

[0094] (Technical Solution 13) The plurality of first regions include In x1 Ga 1-x1 As (0 < x1 < 1), The first intermediate region includes InP, and is the photodetector according to any one of Technical Solutions 1 to 12.

[0095] (Technical Solution 14) The plurality of first regions include In x1 Ga 1-x1 As (0 < x1 < 1), The first intermediate region includes a gas, and is the photodetector according to any one of Technical Solutions 1 to 12.

[0096] (Technical Solution 15) The second electrode includes a linear region extending along the first plane, The laminate includes an overlapping region and a non-overlapping region, The superimposed region overlaps with the linear region in the first direction, The non-overlapping region does not overlap with the linear region in the first direction. The first intermediate region in the non-superimposed region contains a gas, as described in any one of the technical proposals 1 to 12.

[0097] (Technical proposal 16) Further including a reflective member, The optical member includes an optical member side that is inclined with respect to the first plane, At least a portion of the reflective member faces the side surface of the optical member, the photodetector according to any one of Technical Proposals 1 to 15.

[0098] (Technical proposal 17) Further including a reflective member, The photoelectric conversion layer includes a photoelectric conversion layer side surface that is inclined with respect to the first plane, At least a portion of the reflective member faces the side surface of the photoelectric conversion layer, as described in any one of Technical Proposals 1 to 15.

[0099] (Technical proposal 18) Further including an insulating material, The reflective member is continuous with the second electrode, At least a portion of the insulating member is provided between the photoelectric conversion layer and the reflective member, as described in Technical Proposal 17, for the photodetector.

[0100] (Technical proposal 19) The optical component is a photodetector according to any one of Technical Proposals 1 to 18, including a semiconductor.

[0101] (Technical proposal 20) A photodetector according to any one of Technical Proposals 1 to 19, wherein the electrical signal generated between the first electrode and the second electrode is configured to change in response to light incident on the optical member.

[0102] According to the embodiment, a photodetector that can achieve high sensitivity is provided.

[0103] In this specification, "perpendicular" and "parallel" do not mean strictly perpendicular and strictly parallel, but also include variations in the manufacturing process, for example, and it is sufficient if they are substantially perpendicular and substantially parallel.

[0104] The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific configuration of each element included in a photodetector, such as electrodes, laminates, photoelectric conversion layers, optical members, and semiconductor layers, is included within the scope of the present invention as long as those skilled in the art can appropriately select from the known range to implement the present invention and obtain similar effects.

[0105] Furthermore, combinations of two or more elements from any of the specific examples, to the extent technically feasible, are also included within the scope of the present invention, insofar as they encompass the gist of the invention.

[0106] Furthermore, all photodetectors that can be implemented by those skilled in the art by appropriately modifying the design based on the above-described photodetectors as embodiments of the present invention also fall within the scope of the present invention, insofar as they encompass the gist of the present invention.

[0107] Furthermore, within the scope of the concept of the present invention, a person skilled in the art could conceive of various modifications and alterations, and it is understood that such modifications and alterations also fall within the scope of the present invention.

[0108] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0109] 10: Photoelectric conversion layer, 10s: Side surface of photoelectric conversion layer, 11, 12: First and second compound layers, 15: Laminate, 15p: Superimposed region, 15q: Non-superimposed region, 20: Optical component, 20F: Light incident surface, 20s: Side surface of optical component, 21~23: First to third optical layers, 21M~23M: Interlayer region between first and third layers, 21a~23a: First to third regions, 21b~23b: First to third intermediate regions, 21c: First continuous region, 21x~23x: First to third intermediate layers, 31, 32: First and second semiconductor layers, 31p, 31q: First and second partial regions, 41: Insulating component, 51, 52: First and second electrodes, 52L: Linear region, 55: Reflector, 81: Light, 110, 111, 120~123: Photodetector, D1~D3: 1st~3rd directions, PL1: 1st plane, d1, d2: 1st and 2nd distances, p1: 1st pitch, θ1, θ2: 1st and 2nd angles

Claims

1. First electrode and, The second electrode and A laminate, wherein at least a portion of the laminate is provided between the first electrode and the second electrode, Equipped with, The laminated body is A photoelectric conversion layer along the first plane, Optical components and Includes, The photoelectric conversion layer is located between the first electrode and the second electrode in a first direction intersecting the first plane, The direction from the photoelectric conversion layer to the optical member is along the first direction, The optical member includes a first optical layer, The first optical layer is, A plurality of first regions arranged along the first plane, A first intermediate region between the plurality of first regions, Includes, A photodetector wherein the refractive index of the first region of the plurality of first regions is different from the refractive index of the first intermediate region of the first intermediate region.

2. The optical member further includes a second optical layer, The second optical layer is A plurality of second regions arranged along the first plane, A second intermediate region between the plurality of second regions, Includes, The refractive index of the plurality of second regions differs from the refractive index of the second intermediate region of the second intermediate region. The photodetector according to claim 1, wherein the direction from one of the plurality of first regions to one of the plurality of second regions is along the first direction.

3. The optical member further includes a first interlayer region between the first optical layer and the second optical layer, The photodetector according to claim 2, wherein the refractive index of the first interlayer region is different from the refractive index of the second region.

4. The optical member further includes a third optical layer and a second interlayer region between the second optical layer and the third optical layer, The third optical layer is, Multiple third regions arranged along the first plane, A third intermediate region between the plurality of third regions, Includes, The refractive index of the plurality of third regions differs from the refractive index of the third intermediate region of the third intermediate region. The direction from one of the plurality of second regions to one of the plurality of third regions is along the first direction, The photodetector according to claim 2 or 3, wherein the refractive index of the second interlayer region is different from the refractive index of the third region.

5. The photodetector according to claim 2 or 3, wherein the photoelectric conversion layer includes a quantum cascade active layer.

6. The aforementioned plurality of first regions are In ｘ１ Ga １－ｘ１ As (including 0 < x1 < 1), The photodetector according to claim 2 or 3, wherein the first intermediate region includes InP.

7. The aforementioned plurality of first regions are In ｘ１ Ga １－ｘ１ As (including 0 < x1 < 1), The photodetector according to claim 2 or 3, wherein the first intermediate region includes a gas.

8. The second electrode includes a linear region extending along the first plane, The laminate includes an overlapping region and a non-overlapping region, The superimposed region overlaps with the linear region in the first direction, The non-overlapping region does not overlap with the linear region in the first direction. The photodetector according to claim 2 or 3, wherein the first intermediate region in the non-superimposed region contains a gas.

9. Further including a reflective member, The optical member includes an optical member side that is inclined with respect to the first plane, The photodetector according to claim 2 or 3, wherein at least a portion of the reflective member faces the side surface of the optical member.

10. The photodetector according to claim 2 or 3, wherein the electrical signal generated between the first electrode and the second electrode is configured to change in response to light incident on the optical member.

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