Light-emitting device and image display device

Abstract

A light-emitting device according to one embodiment of the present disclosure comprises: a first compound semiconductor layer of a first conductivity type; a second compound semiconductor layer of a second conductivity type; an active layer provided between the first compound semiconductor layer and the second compound semiconductor layer; a third compound semiconductor layer of the first conductivity type provided on a surface of the second compound semiconductor layer, the surface being opposite a surface facing the active layer; a first electrode electrically connected to the first compound semiconductor layer; and a second electrode embedded in the third compound semiconductor layer and electrically connected to the second compound semiconductor layer.

Description

Light-emitting device and image display device

[0001] The present disclosure relates to a light-emitting device and an image display device including the same.

[0002] For example, Patent Document 1 discloses a light-emitting device in which a first conductivity type layer made of an n-type GaN layer, an active layer, and a second conductivity type layer made of a p-type GaN layer are stacked in this order on a substrate.

[0003] Japanese Patent Application Laid-Open No. 2021-132144

[0004] Meanwhile, improvements in device characteristics are required for micro-sized displays.

[0005] It is desirable to provide a light emitting device and an image display device that can improve device characteristics.

[0006] A light emitting device according to one embodiment of the present disclosure includes a first compound semiconductor layer of a first conductivity type, a second compound semiconductor layer of a second conductivity type, an active layer provided between the first compound semiconductor layer and the second compound semiconductor layer, a third compound semiconductor layer of the first conductivity type provided on a surface of the second compound semiconductor layer opposite to a surface facing the active layer, a first electrode electrically connected to the first compound semiconductor layer, and a second electrode embedded in the third compound semiconductor layer and electrically connected to the second compound semiconductor layer.

[0007] An image display device according to an embodiment of the present disclosure includes a light-emitting device, and includes the light-emitting device according to the embodiment of the present disclosure as the light-emitting device.

[0008] In a light-emitting device according to an embodiment of the present disclosure and an image display device according to an embodiment, a first compound semiconductor layer of a first conductivity type, an active layer, and a second compound semiconductor layer of a second conductivity type are stacked in this order, a third compound semiconductor layer of the first conductivity type is formed on the second compound semiconductor layer, and a second electrode electrically connected to the second compound semiconductor layer is embedded in the third compound semiconductor layer, thereby reducing damage to the top surface of the second compound semiconductor layer due to process history and suppressing an increase in operating voltage due to a tunnel junction.

[0009] FIG. 1 is a cross-sectional view (A) and a plan view (B) schematically illustrating an example of a configuration of a light-emitting element and its surroundings according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view illustrating an example of a configuration of a light-emitting device including the light-emitting element shown in FIG. 1. FIG. 3 is a cross-sectional view illustrating an example of a planar configuration of the entire light-emitting device shown in FIG. 2. FIG. 4A is a cross-sectional view illustrating an example of a manufacturing process for the light-emitting element shown in FIG. 1. FIG. 4B is a cross-sectional view illustrating a process subsequent to FIG. 4A. FIG. 4C is a cross-sectional view illustrating a process subsequent to FIG. 4B. FIG. 5A is a cross-sectional view illustrating another example of a manufacturing process for the light-emitting element shown in FIG. 1. FIG. 5B is a cross-sectional view illustrating a process subsequent to FIG. 5A. FIG. 5C is a cross-sectional view illustrating a process subsequent to FIG. 5B. FIG. 5D is a cross-sectional view illustrating a process subsequent to FIG. 5C. FIG. 5E is a cross-sectional view illustrating a process subsequent to FIG. 5D. FIG. 6 is a cross-sectional view illustrating an example of a configuration of a light-emitting device according to a first modification of the present disclosure. FIG. 7 is a cross-sectional view illustrating an example of a configuration of a light-emitting device according to a second modification of the present disclosure. FIG. 8 is a schematic cross-sectional view illustrating an example of the configuration of a light-emitting device according to Modification 3 of the present disclosure. FIG. 9 is a schematic cross-sectional view illustrating an example of the configuration of a light-emitting device according to Modification 4 of the present disclosure. FIG. 10 is a schematic cross-sectional view illustrating an example of the configuration of a light-emitting device according to Modification 5 of the present disclosure. FIG. 11 is a schematic cross-sectional view illustrating an example of the configuration of a light-emitting device according to Modification 6 of the present disclosure. FIG. 12 is a schematic cross-sectional view illustrating an example of the configuration of a light-emitting device according to a second embodiment of the present disclosure. FIG. 13 is a schematic cross-sectional view illustrating an example of the configuration of a light-emitting device according to a third embodiment of the present disclosure. FIG. 14 is a schematic cross-sectional view illustrating an example of the configuration of a light-emitting device according to a fourth embodiment of the present disclosure. FIG. 15 is a schematic cross-sectional view illustrating an example of the configuration of a light-emitting device according to Modification 7 of the present disclosure. FIG. 16 is a schematic cross-sectional view illustrating an example of the configuration of a light-emitting device according to Modification 8 of the present disclosure. FIG. 17 is a schematic cross-sectional view illustrating an example of the configuration of a light-emitting device according to Modification 9 of the present disclosure. FIG. 18 is a schematic cross-sectional view illustrating an example of the configuration of a light-emitting device according to Modification 10 of the present disclosure. Fig. 19A is a front view illustrating an example of the appearance of a digital still camera as an application example of the present disclosure, Fig. 19B is a rear view illustrating an example of the appearance of the digital still camera illustrated in Fig. 19A, and Fig. 20A is a perspective view illustrating the appearance of an example of a head-mounted display as an application example of the present disclosure.Fig. 20B is a perspective view illustrating an external appearance of another example of a head-mounted display as an application example of the present disclosure. Fig. 21 is a perspective view illustrating an external appearance of a television device as an application example of the present disclosure.

[0010] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. The following description is a specific example of the present disclosure, and the present disclosure is not limited to the following aspect. Furthermore, the present disclosure is not limited to the arrangement, dimensions, dimensional ratios, etc. of the components shown in the drawings. The description will be given in the following order. 1. First embodiment (an example of a light emitting device in which a first conductivity type layer, an active layer, a second conductivity type layer, and a first conductivity type layer are stacked, and an electrode layer is embedded in the first conductivity type layer on the second conductivity type layer, and the second conductivity type layer and the electrode layer are directly connected) 2. Modifications 2-1. Modification 1 (another example of the configuration of the light emitting device) 2-2. Modification 2 (another example of the configuration of the light emitting device) 2-3. Modification 3 (another example of the configuration of the light emitting device) 2-4. Modification 4 (another example of the configuration of the light emitting device) 2-5. Modification 5 (another example of the configuration of the light emitting device) 2-6. Modification 6 (another example of the configuration of the light emitting device) 3. 3. Second Embodiment (An example of a light emitting device in which a first conductivity type layer larger than the plane area of ​​the light emitting element is laminated on the second conductivity type layer in a light emitting element in which a first conductivity type layer, an active layer, and a second conductivity type layer are laminated) 4. Third Embodiment (An example of a light emitting device in which a first conductivity type layer is provided that covers, via an insulating film, an upper surface of the second conductivity type layer and side surfaces of the second conductivity type layer, the active layer, and the first conductivity type layer in a light emitting element in which a first conductivity type layer, an active layer, a second conductivity type layer, and a first conductivity type layer are laminated) 5. Fourth Embodiment (An example of a light emitting device in which a first conductivity type layer, an active layer, a second conductivity type layer, and a first conductivity type layer are laminated, and transparent wiring provided on the light extraction surface side is embedded in the first conductivity type layer up to the vicinity of the second conductivity type layer) 6. Modifications 6-1. Modification 7 (Another example of the configuration of the light emitting device) 6-2. Modification 8 (Another example of the configuration of the light emitting device) 6-3. Modification 9 (Another example of the configuration of the light emitting device) 6-4. Modification 10 (another example of the configuration of the light-emitting device) 7. Application examples

[0011] 1. First Embodiment Fig. 1 schematically illustrates an example of a cross-sectional configuration (A) and a planar configuration (B) of a light-emitting element 11 and its surroundings constituting a light-emitting device (light-emitting device 1) according to a first embodiment of the present disclosure. Fig. 2 schematically illustrates an example of a cross-sectional configuration of light-emitting device 1 including light-emitting element 11 shown in Fig. 1. Fig. 3 schematically illustrates an example of the overall planar configuration of light-emitting device 1 shown in Fig. 2. Light-emitting device 1 is suitably applicable to image display devices known as LED displays (for example, electronic viewfinder 1124 of digital still camera 1120, see Fig. 14B).

[0012] The light emitting device 1 of this embodiment has a light emitting element 11 in which a first conductivity type layer 111, an active layer 112, a second conductivity type layer 113, and a first conductivity type layer 114 are stacked in this order. The light emitting element 11 further has an electrode layer 115 electrically connected to the first conductivity type layer 111, and an electrode layer 12 electrically connected to the second conductivity type layer 113. The electrode layer 12 is embedded in the first conductivity type layer 114 and is directly connected to the second conductivity type layer 113.

[0013] Here, the light-emitting element 11 corresponds to a specific example of a "laminate" in an embodiment of the present disclosure. The first conductivity type layer 111 corresponds to a specific example of a "first conductivity type first compound semiconductor layer" in an embodiment of the present disclosure. The active layer 112 corresponds to a specific example of an "active layer" in an embodiment of the present disclosure. The second conductivity type layer 113 corresponds to a specific example of a "second conductivity type second compound semiconductor layer" in an embodiment of the present disclosure. The first conductivity type layer 114 corresponds to a specific example of a "third conductivity type third compound semiconductor layer" in an embodiment of the present disclosure. The electrode layer 115 corresponds to a specific example of a "first electrode" in an embodiment of the present disclosure, and the electrode layer 12 corresponds to a specific example of a "second electrode" in an embodiment of the present disclosure.

[0014] [Configuration of Light-Emitting Device] The light-emitting device 1 has a pixel array section 100A in which a plurality of light-emitting elements 11 are arranged in a two-dimensional array, and a peripheral section 100B provided around the pixel array section 100A. The light-emitting device 1 is, for example, configured such that an element substrate 10 in which a plurality of light-emitting elements 11 are arranged in an array, and a wavelength conversion section 20 are stacked in this order on the surface 30S1 side of a drive substrate 30 having an opposing front surface (surface 30S1) and back surface (surface 30S2).

[0015] The element substrate 10 has a plurality of light-emitting elements 11 arranged in a two-dimensional array in the pixel array section 100A. The light-emitting elements 11 each have a substantially circular shape and are arranged in, for example, a honeycomb pattern, as shown in FIG. 3 . The light-emitting elements 11 are enclosed in an insulating film including an embedding layer 119, as shown in FIG. 1 . Specifically, on the surface 11S1 of the light-emitting elements 11, which serves as the light extraction surface, an insulating layer 13 and an extraction electrode layer 14 are formed in this order on a first conductivity-type layer 114. The insulating layer 13 and the extraction electrode layer 14 surround an electrode layer 12 protruding from the first conductivity-type layer 114. On the surface 11S2 of the light-emitting elements 11, an insulating layer 116 is formed on an electrode layer 115 provided for each element, a protective film 117 and a reflective film 118 are continuous with the light-emitting elements 11, and an embedding layer 119 is formed to embed the light-emitting elements 11. Further formed on the surface 11S2 side of the plurality of light-emitting elements 11 are, in this order, a plug 15 provided for each element, an insulating layer 17 including a pad portion 16A and a pad electrode 16B, and an insulating layer 18 including a pad portion 19 that electrically and physically bonds the element substrate 10 and the drive substrate 30 together.

[0016] The light-emitting element 11 is a solid-state light-emitting element that emits light in a predetermined wavelength band from the surface 11S1, such as an LED (Light Emitting Diode) element. An LED element is an element obtained by separating a wafer used for crystal growth at the wafer level, and is not a package type LED covered with an independently molded resin or the like used in general lighting fixtures. An LED element has a size of, for example, 5 μm to 100 μm, and is known as a micro LED.

[0017] The light-emitting element 11 includes a first conductivity type layer 111, a second conductivity type layer 113, and a first conductivity type layer 114 stacked in this order from the drive substrate 30 side, with the upper surface of the first conductivity type layer 114 serving as a light extraction surface (surface 11S1). An active layer 112 is formed between the first conductivity type layer 111 and the second conductivity type layer 113. Light in the blue band of, for example, 430 nm or more and 500 nm or less is extracted from the active layer 112. In addition to this, light with a wavelength corresponding to, for example, the ultraviolet region (ultraviolet light) may also be extracted from the active layer 112.

[0018] The light emitting element 11 is made of, for example, a III-V group compound semiconductor.

[0019] The first conductivity type layer 111 supplies electrons as active carriers to the active layer 112 by doping or the like. The first conductivity type layer 111 has a pair of opposing surfaces (surface 111S1 and surface 111S2), with surface 111S1 facing the active layer 112. The first conductivity type layer 111 is formed, for example, from an n-type GaN-based semiconductor material. The first conductivity type layer 111 can also be formed, for example, from a phosphorus (P)-based compound semiconductor material such as n-type AlGaInP or GaInP, or n-type AlGaAs.

[0020] The active layer 112 emits and amplifies spontaneously emitted light, and generates stimulated emission light through luminescent recombination of holes and electrons injected from the electrode layers 115 and 12. The active layer 112 has a multiple quantum well (MQW) structure in which multiple well layers and barrier layers are alternately stacked.

[0021] The second conductivity type layer 113 supplies holes as active carriers to the active layer 112 by doping or the like. The second conductivity type layer 113 has a pair of opposing surfaces (surface 113S1 and surface 113S2), with surface 113S1 facing the active layer 112. The second conductivity type layer 113 is formed, for example, from a p-type GaN-based semiconductor material. The second conductivity type layer 113 can also be formed, for example, from a phosphorus (P)-based compound semiconductor material such as p-type AlGaInP or GaInP, or p-type AlGaAs.

[0022] The first-conductivity-type layer 114 is formed directly on the second-conductivity-type layer 113 to protect the second-conductivity-type layer 113 from physical and chemical damage during the manufacturing process. The first-conductivity-type layer 114 has a pair of opposing surfaces (surface 114S1 and surface 114S2), with surface 114S1 in contact with the second-conductivity-type layer 113. In other words, surface 114S2 serves as the light extraction surface (surface 11S1) of the light-emitting element 11. The first-conductivity-type layer 114 is formed, for example, from an n-type GaN-based semiconductor material. The first-conductivity-type layer 114 can also be formed, for example, from a phosphorus (P)-based compound semiconductor material such as n-type AlGaInP or GaInP, or n-type AlGaAs.

[0023] 1, an opening 114H1 penetrating the first conductivity type layer 114 is formed in the first conductivity type layer 114 at approximately the center of the light emitting element 11 in a plan view. An electrode layer 12 is buried in the opening 114H1.

[0024] The electrode layer 12 contacts the second conductivity type layer 113 at the bottom of the opening 114H1 and is directly electrically connected to the second conductivity type layer 113. That is, the electrode layer 12 is in ohmic contact with the second conductivity type layer 113. The electrode layer 12 is formed of a transparent electrode material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO), or TiO. Alternatively, the electrode layer 12 may be a metal electrode made of, for example, a multilayer film (Ti / Al) of titanium (Ti) and aluminum (Al) or a multilayer film (Cr / Au) of chromium (Cr) and gold (Au).

[0025] In the present embodiment, surface 113S2 of second conductivity type layer 113 is covered with first conductivity type layer 114 and electrode layer 12. As described above, first conductivity type layer 114 is intended to protect second conductivity type layer 113 from physical and chemical damage during the manufacturing process, and preferably has higher protective performance than electrode layer 12. In this case, it is preferable that the contact area between electrode layer 12 and second conductivity type layer 113 is smaller than the contact area between first conductivity type layer 114 and second conductivity type layer 113 in a plan view. This further reduces physical and chemical damage to second conductivity type layer 113 during the manufacturing process.

[0026] The insulating layer 13 protects the surfaces 11S1 of the light-emitting elements 11 and also fills in any irregularities on the surfaces 11S1. The insulating layer 13 is made of, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0027] The extraction electrode layer 14 applies a voltage to the second conductivity type layer 113 of each of the plurality of light-emitting elements 11 via the electrode layer 12 and corresponds to a specific example of "external wiring" in one embodiment of the present disclosure. The extraction electrode layer 14 is formed, for example, over the entire surface of the pixel array section 100A as a common electrode for the plurality of light-emitting elements 11 and extends to a part of the peripheral section 100B. The extraction electrode layer 14 formed in the peripheral section 100B is electrically connected to the pad electrode 16B via an opening H1 that penetrates the insulating layer 13, the embedded layer 119, and the protective film 117. The extraction electrode layer 14 is formed of a transparent electrode material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO), or TiO.

[0028] The electrode layer 115 is formed on the lower surface (surface 111S2) of the first conductivity type layer 111 and is in ohmic contact with the first conductivity type layer 111. The electrode layer 115 is formed using, for example, a multilayer film (Ni / Au) of nickel (Ni) and gold (Au).

[0029] The insulating layer 116 protects the electrode layer 115. The insulating layer 116 is made of, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0030] The protective film 117 is intended to protect the top and side surfaces of the GaN chips constituting the light-emitting elements 11. The protective film 117 is formed continuously on the surface 111S2 of the first-conductivity-type layer 111 and the side surfaces of the light-emitting elements 11 including the first-conductivity-type layer 111, the active layer 112, the second-conductivity-type layer 113, and the first-conductivity-type layer 114, with the electrode layer 115 and the insulating layer 116 interposed therebetween. In other words, the protective film 117 extends, for example, over the entire pixel array section 100A, and is formed over the surface 11S2 facing the drive substrate 30 and the side surfaces of each of the plurality of light-emitting elements 11 arranged in a two-dimensional array. The protective film 117 is made of, for example, silicon oxide (SiO), silicon nitride (SiN), aluminum oxide (Al ２ O ３ ), aluminum nitride (AlN), or the like, or a laminated film thereof.

[0031] A reflective film 118 is formed on the protective film 117, in the same manner as the protective film 117, and is continuous with the plurality of light-emitting elements 11. The reflective film 118 has an opening 118H on the surface 11S2 side of the light-emitting element 11, and a plug 15 is formed in the opening 118H. The reflective film 118 may be made of, for example, a metal having high reflectivity in the visible light range. Specific examples of the material include silver (Ag), aluminum (Al), copper (Cu), gold (Au), platinum (Pt), rhodium (Rh), and alloys thereof.

[0032] The embedding layer 119 embeds the plurality of light emitting elements 11 and forms flat front and back surfaces of the element substrate 10. The embedding layer 119 is made of an insulating material such as silicon oxide (SiO) or silicon nitride (SiN).

[0033] The plugs 15 apply a voltage to the first conductivity type layers 111 of the plurality of light emitting elements 11. The plugs 15 are formed using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or alloys thereof.

[0034] An insulating layer 17 is provided on the drive substrate 30 side of the embedded layer 119. In the insulating layer 17, a plurality of pad portions 16A provided for each light-emitting element 11A in the pixel array portion 100A, a plurality of pad electrodes 16B provided in the peripheral portion 100B, and vias are formed. The insulating layer 17 is formed of, for example, silicon oxide (SiO) or silicon nitride (SiN). The pad portions 16A, pad electrodes 16B, and vias are formed of, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or an alloy thereof.

[0035] Further provided on the drive substrate 30 side of the insulating layer 17 are an insulating layer 18 that forms a bonding surface with the drive substrate 30, and a plurality of pads 19 that are embedded in the insulating layer 18. The insulating layer 18 is made of, for example, silicon oxide (SiO) or silicon nitride (SiN). The pads 19 are made of, for example, copper (Cu).

[0036] The wavelength conversion unit 20 is provided on the light emission side S1 of the element substrate 10. The wavelength conversion unit 20 includes a planarization layer 21, a partition layer 22 having an opening 22H for each light emitting element 11, and a wavelength conversion layer 23 formed in the opening 22H. A reflective film 24 is further provided between the partition layer 22 and the wavelength conversion layer 23. A protective layer 25 is further provided on the light emission side S1 of the wavelength conversion layer 23, and a wavelength selection layer 26 is provided in the protective layer 25. An on-chip lens layer 27 is further provided on the protective layer 25.

[0037] The planarization layer 21 is intended to planarize the surface on the light-emitting side S1 of the element substrate 10. The planarization layer 21 is made of, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0038] The partition layer 22 is intended to prevent color mixing due to light leakage between adjacent RGB subpixels (red pixel Pr, green pixel Pg, and blue pixel Pb) when the light-emitting device 1 is applied to an image display device. The partition layer 22 is provided, for example, in a honeycomb shape. Specifically, the partition layer 22 has, for example, a substantially circular opening 22H for each of the plurality of light-emitting elements 11 arranged in a two-dimensional array. In cross-sectional view, the opening 22H has an inclined surface, for example, at an angle of less than 90° with respect to the surface 20S2 of the wavelength conversion section 20 opposite the surface 20S1. In other words, in cross-sectional view, the partition layer 22 has a forward tapered shape between adjacent color pixels Pr, Pg, and Pb. The partition layer 22 is preferably formed using a material with high thermal conductivity and electrical conductivity, such as a metal material such as copper (Cu), aluminum (Al), gold (Au), nickel (Ni), or platinum (Pt).

[0039] The wavelength conversion layer 23 converts light emitted from the plurality of light-emitting elements 11 into a desired wavelength (e.g., red (R) / green (G) / blue (B)) and emits the converted light, and is formed in an opening 22H provided above each light-emitting element 11. Specifically, the red pixel Pr is provided with a red wavelength conversion layer 23R that converts light emitted from the light-emitting elements 11 into light in a red band (red light), the green pixel Pg is provided with a green wavelength conversion layer 23G that converts light emitted from the light-emitting elements 11 into light in a green band (green light), and the blue pixel Pb is provided with a blue wavelength conversion layer 23B that converts light emitted from the light-emitting elements 11 into light in a blue band (blue light).

[0040] Each wavelength conversion layer 23R, 23G, 23B can be formed using quantum dots corresponding to each color. Specifically, when red light is obtained, the quantum dots can be selected from, for example, InP, GaInP, InAsP, CdSe, CdZnSe, CdTeSe, or CdTe. When green light is obtained, the quantum dots can be selected from, for example, InP, GaInP, ZnSeTe, ZnTe, CdSe, CdZnSe, CdS, or CdSeS. When blue light is obtained, the quantum dots can be selected from, for example, ZnSe, ZnTe, ZnSeTe, CdSe, CdZnSe, CdS, CdZnS, and CdSeS. Note that when blue light is emitted from the light-emitting element 11 as described above, the blue wavelength conversion layer 23B may be formed from a light-transmitting resin layer.

[0041] The reflective film 24 is provided on the side surface of the opening 22H to efficiently extract the color light emitted from the light-emitting element 11 and converted in the wavelength conversion layers 23R, 23G, and 23B from the light extraction surface (surface 22S1) of the wavelength conversion layer 23. The reflective film 24 is formed using a metal material with optical reflectivity. Examples of the metal material for the reflective film 24 include metals with high reflectivity in the visible light range. Specific examples of the material include silver (Ag), aluminum (Al), copper (Cu), gold (Au), platinum (Pt), rhodium (Rh), and alloys thereof.

[0042] It should be noted that the reflective film 24 does not necessarily have to be formed when the partition wall layer 22 is formed using the above-mentioned metal material having light reflectivity.

[0043] The protective layer 25 is for protecting the surface of the light emitting device 1 and is made of, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0044] A wavelength selection layer 26 is provided across the red pixel Pr and the green pixel Pg within the protective layer 25. The wavelength selection layer 26 selectively reflects, for example, light in the blue wavelength band (blue light), thereby improving the color purity of the red light and green light extracted from the red pixel Pr and the green pixel Pg, respectively.

[0045] The on-chip lens layer 27 is provided so as to cover the entire surfaces of the pixel array unit 100A and the peripheral unit 100B. The on-chip lens layer 27 is made of a light-transmitting material, and is made of, for example, a single-layer film made of any of silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiCN), etc., or a stacked film made of two or more of these materials.

[0046] The peripheral portion 100B has an opening H2 that passes through the on-chip lens layer 27, the protective layer 25, the partition layer 22, the planarizing layer 21, the insulating layer 13, the embedded layer 119, the protective film 117, and the insulating layers 17, 18, and 33 in this order, and reaches the pad electrode 35 provided in the interlayer insulating layer 32. The pad electrode 35 exposed at the bottom of this opening H2 is used as an electrode for connection to the outside.

[0047] The drive substrate 30 is provided with a drive circuit and the like that controls the driving of the plurality of light-emitting elements 11 arranged in the pixel array section 100A. The drive substrate 30 has a support substrate 31 made of, for example, silicon (Si), an interlayer insulating layer 32 that is provided on the support substrate 31 and includes a plurality of wiring layers (for example, wiring layers M1, M2, M3, and M4) and vias that electrically connect the wiring layers, an insulating layer 33 that forms a bonding surface with the element substrate 10, and pad sections 34 that are embedded in the insulating layer 33.

[0048] The interlayer insulating layer 32 is made of, for example, silicon oxide (SiO) or silicon nitride (SiN).

[0049] The wiring layers M1, M2, M3, M4, and M5 and the vias electrically connecting the wiring layers are formed using, for example, copper (Cu), aluminum (Al), tungsten (W), silver (Ag), or alloys thereof. The insulating layer 33 is formed using, for example, silicon oxide (SiO), silicon nitride (SiN), or the like. The pad electrode 35 is formed using, for example, copper (Cu).

[0050] [Method 1 for Manufacturing Light-Emitting Device] The light-emitting device 11 of this embodiment can be manufactured, for example, as follows: Figures 4A to 4C show an example of a manufacturing process for the light-emitting device 1.

[0051] First, for example, a compound semiconductor layer is formed by epitaxial crystal growth using a silicon substrate as a growth substrate, such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE), in which a first conductivity type layer 114, a second conductivity type layer 113, an active layer 112, and a first conductivity type layer 111 are stacked in this order from the growth substrate side. That is, the first conductivity type layer 114, the second conductivity type layer 113, the active layer 112, and the first conductivity type layer 111 are connected to each other at the crystalline level. Next, an electrode layer 115 and an insulating layer 116 are formed on the compound semiconductor layer 110 by, for example, chemical vapor deposition (CVD). Thereafter, the compound semiconductor layer 110 including the electrode layer 115 and the insulating layer 116 is divided into individual pieces, and then the insulating layer 116, the electrode layer 115 and the compound semiconductor layer 110 are etched using, for example, photolithography technology to process them into a plurality of light-emitting elements 11.

[0052] Next, as shown in FIG. 4A, the periphery of the light emitting element 11 is buried with an insulating film including a buried layer 119, and the wiring layer 16 including the plug 15 and the pad portion 16A is formed on the electrode layer 115 side.

[0053] Subsequently, as shown in FIG. 4B, an opening 114H1 penetrating the insulating film and the first conductivity type layer 114 is formed using, for example, photolithography.

[0054] 4C , a conductive film is embedded in the opening 114H by, for example, a CVD method, and then the conductive film formed on the insulating film is removed by polishing by, for example, CMP, thereby forming the electrode layer 12.

[0055] Thereafter, a transparent electrode film is formed by, for example, CVD, and then the transparent electrode film is patterned by, for example, photolithography to form the extraction electrode layer 14. In this way, the light emitting element 11 shown in FIG.

[0056] [Method 2 for Manufacturing Light-Emitting Device] The light-emitting device 11 of this embodiment can be manufactured, for example, as follows: Figures 5A to 5E show another example of the manufacturing process for the light-emitting device 1.

[0057] First, for example, a compound semiconductor layer is formed by epitaxial crystal growth using a silicon substrate as a growth substrate, using a method such as MOCVD or MBE, in which a second conductivity type layer 113, an active layer 112, and a first conductivity type layer 111 are stacked in this order from the growth substrate side. Next, an electrode layer 115 and an insulating layer 116 are formed on the compound semiconductor layer 110 by, for example, CVD. Thereafter, the compound semiconductor layer 110 including the electrode layer 115 and the insulating layer 116 is divided into individual pieces, and the insulating layer 116, the electrode layer 115, and the compound semiconductor layer 110 are etched using, for example, photolithography technology, to process the light-emitting elements 11 into individual pieces.

[0058] Next, as shown in FIG. 5A, the periphery of the light emitting element 11 is buried with an insulating film including a buried layer 119, and the wiring layer 16 including the plug 15 and the pad portion 16A is formed on the electrode layer 115 side.

[0059] Subsequently, as shown in FIG. 5B, a first conductivity type layer 114 is formed at a low temperature using, for example, sputtering and ion implantation.

[0060] Next, as shown in FIG. 5C, the first conductive type layer 114 is patterned using, for example, photolithography, and then an insulating film is further formed around the light emitting element 11.

[0061] Subsequently, as shown in FIG. 5D, an opening 114H1 penetrating the insulating film and the first conductivity type layer 114 is formed using, for example, photolithography.

[0062] 5E, a conductive film is embedded in the opening 114H by, for example, a CVD method, and then the conductive film formed on the insulating film is removed by polishing by, for example, CMP, thereby forming the electrode layer 12.

[0063] Thereafter, in the same manner as in the above-described manufacturing method 1, a transparent electrode film is formed by, for example, a CVD method, and then the transparent electrode film is patterned by, for example, a photolithography technique to form the extraction electrode layer 14. In this manner, the light-emitting element 11 shown in FIG.

[0064] [Actions and Effects] In the light-emitting device 1 of the present embodiment, in the light-emitting element 11 in which the first conductivity-type layer 111, the active layer 112, the second conductivity-type layer 113, and the first conductivity-type layer 114 are stacked in this order from the surface 11S2 side opposite the light extraction surface (surface 11S1), the electrode layer 12 is embedded in the first conductivity-type layer 114, and the second conductivity-type layer 113 and the electrode layer 12 are directly connected. This reduces damage to the second conductivity-type layer 113 due to process history while suppressing an increase in operating voltage due to a tunnel junction. This is described below.

[0065] In recent years, high-definition image display devices using light-emitting devices with gallium nitride (GaN) micro-LEDs as light sources have become widespread. In such light-emitting devices, singulated GaN chips are further processed to form multiple elements (micro-LEDs) in an array. Various process histories during the manufacturing process, such as plasma exposure during dry etching and chemical exposure during chemical etching, can physically and chemically damage the exposed p-type semiconductor layer, deactivating it and reducing its light-emitting properties.

[0066] To solve this problem, microLEDs using a tunnel junction, in which an n-type semiconductor layer is placed on a p-type semiconductor layer, have been reported. However, microLEDs in which an n-type semiconductor layer is simply placed on a p-type semiconductor layer have problems with degradation of characteristics, such as increased power consumption due to the high operating voltage inherent to tunnel junctions.

[0067] In contrast, in the present embodiment, in the light-emitting element 11 in which the first conductivity-type layer 111, the active layer 112, and the second conductivity-type layer 113 are stacked in this order from the surface 11S2 side opposite to the light extraction surface (surface 11S1), the first conductivity-type layer 114 is stacked on the second conductivity-type layer 113. This reduces damage to the second conductivity-type layer 113 due to process history. Furthermore, in the present embodiment, the electrode layer 12 is embedded in the first conductivity-type layer 114, and the second conductivity-type layer 113 and the electrode layer 12 are directly connected, thereby suppressing an increase in operating voltage due to a tunnel junction.

[0068] As a result, it is possible to improve the device characteristics of the light emitting device 1 of this embodiment and an image display device including the same.

[0069] Next, second to fourth embodiments, first to tenth modifications, and application examples of the present disclosure will be described. Note that components corresponding to those of the light emitting device 1 of the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0070] 6 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1A) according to Modification 1 of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 1A is suitable for use in image display devices known as LED displays (for example, the electronic viewfinder 1124 of a digital still camera 1120).

[0071] In the first embodiment described above, an example has been shown in which the electrode layer 12 embedded in the first conductivity type layer 114 penetrates between the surfaces 114S1 and 114S2 of the first conductivity type layer 114 and is directly connected to the extraction electrode layer 14, but this is not limiting. In the light emitting device 1A of this modification, the electrode layer 12 is embedded in the first conductivity type layer 114, and the electrode layer 12 and the extraction electrode layer 14 are electrically connected via a plug 41. Except for this point, the light emitting device 1A has substantially the same configuration as the light emitting device 1 of the first embodiment described above.

[0072] Even with this configuration, the light emitting device 1A of this modification can achieve the same effects as the light emitting device 1 of the first embodiment.

[0073] 7 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1B) according to Modification 2 of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 1B is suitable for use in image display devices known as LED displays (for example, the electronic viewfinder 1124 of a digital still camera 1120).

[0074] In the first embodiment described above, an example was shown in which the electrode layer 12 embedded in the first conductivity type layer 114 penetrates between the surfaces 114S1 and 114S2 of the first conductivity type layer 114 and is directly connected to the extraction electrode layer 14, but this is not limited to this. In the light emitting device 1B of this modification, the electrode layer 12 is embedded in the first conductivity type layer 114, and the electrode layer 12A is extended from the side surface of the first conductivity type layer 114 to the outside of the light emitting element 11. Except for this point, the light emitting device 1B has substantially the same configuration as the light emitting device 1 of the first embodiment described above.

[0075] The electrode layer 12A is in contact with the second conductivity type layer 113 and is directly electrically connected to the second conductivity type layer 113. In other words, the electrode layer 12A is in ohmic contact with the second conductivity type layer 113. The electrode layer 12A is formed of a transparent electrode material such as ITO, IZO, SnO, or TiO.

[0076] Even with this configuration, the light emitting device 1B of this modified example can achieve the same effects as the light emitting device 1 of the first embodiment.

[0077] 8 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1C) according to Modification 3 of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 1C is suitable for use in image display devices known as LED displays (for example, the electronic viewfinder 1124 of a digital still camera 1120).

[0078] Although the above-described modified example 2 shows an example in which the electrode layer 12A embedded in the first conductivity type layer 114 is extended to the outside of the light emitting element 11 from the side surface of the first conductivity type layer 114, the present invention is not limited to this. In the light emitting device 1C of this modified example, the extraction electrode layer 14 is embedded in the first conductivity type layer 114 together with the electrode layer 12, and the extraction electrode layer 14 is extended to the outside of the light emitting element 11 from the side surface of the first conductivity type layer 114. Except for this point, the light emitting device 1C has substantially the same configuration as the light emitting device 1 of the above-described first embodiment.

[0079] Even with this configuration, the light emitting device 1C of this modified example can achieve the same effects as the light emitting device 1 of the first embodiment.

[0080] 9 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1D) according to Modification 4 of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 1D is suitable for use in image display devices known as LED displays (for example, the electronic viewfinder 1124 of a digital still camera 1120).

[0081] In the first embodiment described above, an example was shown in which the electrode layer 12 embedded in the first conductivity type layer 114 penetrates between the surfaces 114S1 and 114S2 of the first conductivity type layer 114 and is directly connected to the extraction electrode layer 14, but this is not limiting. In the light emitting device 1D of this modification, a second conductivity type region 114A is formed in a part of the first conductivity type layer 114, and an electrode layer 12 is formed on this second conductivity type region 114A. Except for this point, the light emitting device 1D has substantially the same configuration as the light emitting device 1 of the first embodiment described above.

[0082] The second conductivity type region 114A can be formed, for example, by doping a first conductivity type layer 114 made of an n-type GaN-based semiconductor material with p-type impurities, for example, by ion implantation. The second conductivity type region 114A penetrates between the surfaces 114S1 and 114S2 of the first conductivity type layer 114, and the electrode layer 12 is formed on this second conductivity type region 114A. This results in a configuration in which the electrode layer 12 and the second conductivity type layer 113 are substantially directly connected.

[0083] Even with this configuration, the light emitting device 1D of this modified example can achieve the same effects as the light emitting device 1 of the first embodiment.

[0084] 10 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1E) according to Modification 5 of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 1E is suitably applicable to image display devices known as LED displays (for example, the electronic viewfinder 1124 of a digital still camera 1120).

[0085] In the first embodiment, the first conductivity-type layer 114 is formed only on the surface 113S2 of the second conductivity-type layer 113, but this is not limiting. In the light-emitting device 1E of this modification, the first conductivity-type layer 114 extends from the surface 113S2 of the second conductivity-type layer 113 to the side surfaces of the second conductivity-type layer 113, the active layer 112, and the first conductivity-type layer 111, and an undoped layer 141 is formed between the first conductivity-type layer 114 and each of the layers 111, 112, and 113. Here, the undoped layer 141 corresponds to a specific example of a "fourth compound semiconductor layer" in one embodiment of the present disclosure. Except for this point, the light-emitting device 1E has substantially the same configuration as the light-emitting device 1 of the first embodiment.

[0086] In this manner, in light emitting device 1E of this modification, first conductivity type layer 114 is extended to surface 113S2 of second conductivity type layer 113 and to the side surfaces of second conductivity type layer 113, active layer 112, and first conductivity type layer 111 via undoped layer 141. This makes it possible to further reduce damage to second conductivity type layer 113 due to process history, and light emitting device 1E can further improve the device characteristics.

[0087] 11 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 1F) according to Modification 6 of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 1F is suitable for use in image display devices known as LED displays (for example, the electronic viewfinder 1124 of a digital still camera 1120).

[0088] In the above-described modification 5, an example in which the undoped layer 141 is formed between the first conductivity type layer 114 and each of the layers 111, 112, and 113 has been described, but the present invention is not limited to this. An insulating film 42 is formed between the first conductivity type layer 114 and each of the layers 111, 112, and 113. Except for this point, the light emitting device 1F has substantially the same configuration as the light emitting device 1E of modification 5.

[0089] The insulating film 42 is made of, for example, silicon oxide (SiO) or aluminum oxide (Al) formed by atomic layer deposition (ALD). ２ O ３ ) etc.

[0090] In this manner, in light emitting device 1F of this modification, first conductivity type layer 114 is extended via insulating film 42 to surface 113S2 of second conductivity type layer 113 and to the side surfaces of second conductivity type layer 113, active layer 112, and first conductivity type layer 111. This makes it possible to further reduce damage to second conductivity type layer 113 due to process history, as in modification 5 above, and light emitting device 1F can therefore further improve the device characteristics.

[0091] 12 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 2) according to a second embodiment of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 2 is suitable for use in an image display device known as an LED display (e.g., an electronic viewfinder 1124 of a digital still camera 1120).

[0092] Light-emitting device 2 of the present embodiment includes light-emitting element 11A in which first conductivity-type layer 111, active layer 112, second conductivity-type layer 113, and first conductivity-type layer 114B are stacked in this order. Light-emitting element 11A further includes electrode layer 115 electrically connected to first conductivity-type layer 111 and electrode layer 12 electrically connected to second conductivity-type layer 113. First conductivity-type layer 114B extends outside first conductivity-type layer 111, active layer 112, and second conductivity-type layer 113 in a plan view, and electrode layer 12 is formed on first conductivity-type layer 114B.

[0093] Here, the light-emitting element 11A corresponds to a specific example of a "laminate" in an embodiment of the present disclosure. The first conductivity type layer 111 corresponds to a specific example of a "first conductivity type first compound semiconductor layer" in an embodiment of the present disclosure. The active layer 112 corresponds to a specific example of an "active layer" in an embodiment of the present disclosure. The second conductivity type layer 113 corresponds to a specific example of a "second conductivity type second compound semiconductor layer" in an embodiment of the present disclosure. The first conductivity type layer 114B corresponds to a specific example of a "third conductivity type third compound semiconductor layer" in an embodiment of the present disclosure. The electrode layer 115 corresponds to a specific example of a "first electrode" in an embodiment of the present disclosure, and the electrode layer 12 corresponds to a specific example of a "second electrode" in an embodiment of the present disclosure.

[0094] The first conductivity type layer 114B is intended to protect the second conductivity type layer 113 from physical and chemical damage during the manufacturing process, and is stacked directly on the second conductivity type layer 113. The first conductivity type layer 114B has a pair of opposing surfaces (surface 114S1 and surface 114S2), and surface 114S1 is in contact with the second conductivity type layer 113. In other words, surface 114S2 serves as the light extraction surface (surface 11S1) of the light-emitting element 11.

[0095] The first conductivity type layer 114B is formed of a semiconductor material of a conductivity type different from that of the second conductivity type layer 113, for example, an n-type GaN-based semiconductor material. The first conductivity type layer 114B can also be formed of, for example, a phosphorus (P)-based compound semiconductor material such as n-type AlGaInP or GaInP, or n-type AlGaAs.

[0096] As described above, the first conductivity type layer 114B extends further outward than the first conductivity type layer 111, the active layer 112, and the second conductivity type layer 113. In other words, the first conductivity type layer 114B is formed to have a larger area than the first conductivity type layer 111, the active layer 112, and the second conductivity type layer 113.

[0097] As described above, in light-emitting device 2 of the present embodiment, first conductivity type layer 114B is formed to have a larger area than first conductivity type layer 111, active layer 112, and second conductivity type layer 113. This reduces damage to second conductivity type layer 113 due to process history.

[0098] As a result, it is possible to improve the device characteristics of the light emitting device 2 of this embodiment and an image display device including the same.

[0099] 13 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 3) according to a third embodiment of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 3 is suitably applicable to image display devices known as LED displays (e.g., the electronic viewfinder 1124 of a digital still camera 1120).

[0100] The light-emitting device 3 of this embodiment includes a light-emitting element 11B including a first-conductivity-type layer 111, an active layer 112, a second-conductivity-type layer 113, and a first-conductivity-type layer 114C stacked in this order. The light-emitting element 11B further includes an electrode layer 115 electrically connected to the first-conductivity-type layer 111 and an electrode layer 12 electrically connected to the second-conductivity-type layer 113. The first-conductivity-type layer 114C extends to a surface 113S2 of the second-conductivity-type layer 113 and to the side surfaces of the second-conductivity-type layer 113, the active layer 112, and the first-conductivity-type layer 111, and the electrode layer 12 is formed on the first-conductivity-type layer 114C. An insulating film 42 is formed between the first-conductivity-type layer 114 and each of the layers 111, 112, and 113.

[0101] Here, the light-emitting element 11B corresponds to a specific example of a "laminate" in an embodiment of the present disclosure. The first conductivity type layer 111 corresponds to a specific example of a "first conductivity type first compound semiconductor layer" in an embodiment of the present disclosure. The active layer 112 corresponds to a specific example of an "active layer" in an embodiment of the present disclosure. The second conductivity type layer 113 corresponds to a specific example of a "second conductivity type second compound semiconductor layer" in an embodiment of the present disclosure. The first conductivity type layer 114C corresponds to a specific example of a "third conductivity type third compound semiconductor layer" in an embodiment of the present disclosure. The electrode layer 115 corresponds to a specific example of a "first electrode" in an embodiment of the present disclosure, and the electrode layer 12 corresponds to a specific example of a "second electrode" in an embodiment of the present disclosure.

[0102] The first-conductivity-type layer 114C is intended to protect the second-conductivity-type layer 113 from physical and chemical damage during the manufacturing process and is stacked directly on the second-conductivity-type layer 113. The first-conductivity-type layer 114C has a pair of opposing surfaces (surface 114S1 and surface 114S2), with surface 114S1 in contact with the second-conductivity-type layer 113. In other words, surface 114S2 serves as the light extraction surface (surface 11S1) of the light-emitting element 11. As described above, the first-conductivity-type layer 114C extends to surface 113S2 of the second-conductivity-type layer 113 and the side surfaces of the second-conductivity-type layer 113, active layer 112, and first-conductivity-type layer 111.

[0103] The first conductivity type layer 114C is formed of a semiconductor material of a conductivity type different from that of the second conductivity type layer 113, for example, an n-type GaN-based semiconductor material. The first conductivity type layer 114C can also be formed of, for example, a phosphorus (P)-based compound semiconductor material such as n-type AlGaInP or GaInP, or n-type AlGaAs.

[0104] The insulating film 42 is formed of, for example, silicon oxide (SiO) or silicon nitride (SiN). The insulating film 42 has an opening 42H on the surface 113S2 of the second conductivity type layer 113. The second conductivity type layer 113 and the first conductivity type layer 114 are in direct contact with each other within this opening 42H.

[0105] As described above, in the light-emitting device 3 of the present embodiment, the first conductivity type layer 114 is extended via the insulating film 42 to the surface 113S2 of the second conductivity type layer 113 and to the side surfaces of the second conductivity type layer 113, the active layer 112, and the first conductivity type layer 111. This reduces damage to the second conductivity type layer 113 due to the process history.

[0106] As a result, it is possible to improve the device characteristics of the light emitting device 3 of this embodiment and an image display device including the same.

[0107] 14 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 4) according to a fourth embodiment of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 4 is suitably applicable to image display devices known as LED displays (e.g., the electronic viewfinder 1124 of a digital still camera 1120).

[0108] The light-emitting device 4 of the present embodiment includes a light-emitting element 11C in which a first-conductivity-type layer 111, an active layer 112, a second-conductivity-type layer 113, and a first-conductivity-type layer 114B are stacked in this order. The light-emitting element 11C further includes an electrode layer 115 electrically connected to the first-conductivity-type layer 111, and an extraction electrode layer 14A embedded in the first-conductivity-type layer 114 up to the vicinity of the second-conductivity-type layer 113. The first-conductivity-type layer 114 is present between the second-conductivity-type layer 113 and the extraction electrode layer 14A embedded in the first-conductivity-type layer 114.

[0109] Here, the light-emitting element 11C corresponds to a specific example of a "laminate" in an embodiment of the present disclosure. The first conductivity type layer 111 corresponds to a specific example of a "first conductivity type first compound semiconductor layer" in an embodiment of the present disclosure. The active layer 112 corresponds to a specific example of an "active layer" in an embodiment of the present disclosure. The second conductivity type layer 113 corresponds to a specific example of a "second conductivity type second compound semiconductor layer" in an embodiment of the present disclosure. The first conductivity type layer 114 corresponds to a specific example of a "third conductivity type third compound semiconductor layer" in an embodiment of the present disclosure. The electrode layer 115 corresponds to a specific example of a "first electrode" in an embodiment of the present disclosure, and the extraction electrode layer 14A corresponds to a specific example of a "second electrode" in an embodiment of the present disclosure.

[0110] The extraction electrode layer 14A applies a voltage to the second conductivity-type layer 113 of each of the plurality of light-emitting elements 11C. The extraction electrode layer 14A is formed, for example, over the entire surface of the pixel array unit 100A as a common electrode for the plurality of light-emitting elements 11C. The extraction electrode layer 14A is embedded in the first conductivity-type layer 114 up to the vicinity of the second conductivity-type layer 113 for each light-emitting element 11C. A thin first conductivity-type layer 114 exists between the second conductivity-type layer 113 and the extraction electrode layer 14A. As in the first embodiment, the extraction electrode layer 14A extends to a portion of the peripheral portion 100B. The extraction electrode layer 14A formed in the peripheral portion 100B is electrically connected to the pad electrode 16B via an opening H1 that penetrates the insulating layer 13, the embedded layer 119, and the protective film 117. The extraction electrode layer 14A is formed of a transparent electrode material such as ITO, IZO, SnO, or TiO.

[0111] As described above, in the light-emitting device 4 of the present embodiment, the extraction electrode layer 14, which is a common electrode for the plurality of light-emitting elements 11, is embedded in the first-conductivity-type layer 114 up to the vicinity of the second-conductivity-type layer 113 for each light-emitting element 11C. This reduces damage to the second-conductivity-type layer 113 due to process history, while suppressing an increase in operating voltage due to a tunnel junction.

[0112] As a result, it is possible to improve the device characteristics of the light emitting device 4 of this embodiment and an image display device including the same.

[0113] 15 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 5A) according to Modification 7 of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 5A is suitable for use in image display devices known as LED displays (for example, the electronic viewfinder 1124 of a digital still camera 1120).

[0114] In the first embodiment, an example was shown in which the electrode layer 12 electrically connected to the second conductivity-type layer 113 was formed on the surface 11S1, which serves as the light extraction surface, and the electrode layer 115 electrically connected to the first conductivity-type layer 111 was formed on the surface 11S2 opposite the surface 11S1, but this is not limited to this. In the light-emitting device 5A of this modification, the first conductivity-type layer 111 extends beyond the active layer 112, the second conductivity-type layer 113, and the first conductivity-type layer 114 in a planar view, and the electrode layer 115 is formed on the surface 111S1 on the light-emitting side S1. Except for this point, the light-emitting device 5A has substantially the same configuration as the light-emitting device 1 of the first embodiment.

[0115] Even with this configuration, the light emitting device 5A of this modification can achieve the same effects as the light emitting device 1 of the first embodiment.

[0116] 16 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 5B) according to Modification 8 of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 5B is suitable for use in image display devices known as LED displays (for example, the electronic viewfinder 1124 of a digital still camera 1120).

[0117] In the light emitting device 5B of this modification, the surface 114S2 of the first conductivity type layer 114D, which serves as the light extraction surface, is roughened. Except for this, the light emitting device 5B has substantially the same configuration as the light emitting device 1 of the first embodiment.

[0118] In this way, in the light emitting device 5B of this modification, the surface 114S2 of the first conductivity type layer 114D, which serves as the light extraction surface, is roughened. This changes the angle of the light that is totally reflected at the surface 114S2, reducing the light component that is trapped within the device and cannot be extracted to the outside. Therefore, in addition to the effects of the first embodiment, it is possible to improve the light extraction efficiency.

[0119] 17 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 5C) according to Modification 9 of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 5C is suitable for use in image display devices known as LED displays (for example, the electronic viewfinder 1124 of a digital still camera 1120).

[0120] In the light emitting device 5C of this modification, a photonic crystal structure X, which is a periodic structure smaller than the emission wavelength, is formed on a surface 114S2 of a first conductivity type layer 114E, which serves as a light extraction surface. Except for this point, the light emitting device 5C has substantially the same configuration as the light emitting device 1 of the first embodiment.

[0121] In this way, in the light emitting device 5C of this modification, a photonic crystal structure X, which is a periodic structure smaller than the emission wavelength, is formed on the surface 114S2 of the first conductivity type layer 114E, which serves as the light extraction surface. The photon effect of this photonic crystal structure X changes the angular component of light that is totally reflected at the surface 114S2, reducing the component of light that is trapped within the element and cannot be extracted to the outside. Therefore, in addition to the effects of the first embodiment described above, it is possible to improve the light extraction efficiency.

[0122] 18 is a schematic diagram illustrating an example of a cross-sectional configuration of a light-emitting device (light-emitting device 5D) according to Modification 10 of the present disclosure. Similar to the light-emitting device 1 of the first embodiment, the light-emitting device 5D is suitable for use in image display devices known as LED displays (for example, the electronic viewfinder 1124 of a digital still camera 1120).

[0123] In the light emitting device 5D of this modification, the surface 114S2 of the first conductivity type layer 114F, which serves as the light extraction surface, is formed as, for example, a convex lens surface. Except for this, the light emitting device 5D has substantially the same configuration as the light emitting device 1 of the first embodiment.

[0124] In this way, in the light emitting device 5D of this modification, the surface 114S2 of the first conductivity type layer 114F, which serves as the light extraction surface, is made lens-shaped. This increases the proportion of light incident on the lens that is disposed above the light emitting device and captures light emitted from the light emitting device. Therefore, in addition to the effects of the first embodiment, the light emitting device 5D of this modification can improve the light extraction efficiency.

[0125] Although the above-described modified examples 7 to 10 show examples in which the techniques of the respective modified examples are applied to the light-emitting device 1 of the first embodiment, the present invention is not limited to this. The techniques of the modified examples 7 to 10 can also be applied to any of the above-described second to fourth embodiments.

[0126] 7. Application Examples Application Example 1 Fig. 19A is a front view showing an example of the appearance of a digital still camera (electronic device) 1120. Fig. 19B is a rear view showing an example of the appearance of the digital still camera 1120. The digital still camera 1120 is a single-lens reflex camera with interchangeable lenses. The digital still camera 1120 has an interchangeable taking lens unit (interchangeable lens) 1121 located approximately in the center of the front of a camera main body (camera body) 1122, and a grip portion 1123 for the photographer to hold on the left side of the front.

[0127] A monitor 1126 is provided at a position shifted to the left from the center of the back of the camera body 1122. An electronic viewfinder (eyepiece window) 1124 is provided above the monitor 1126. By looking through the electronic viewfinder 1124, the photographer can visually confirm the optical image of the subject guided by the photographing lens unit 1121 and determine the composition. The electronic viewfinder 1124 is equipped with a light-emitting device 1.

[0128] (Application Example 2) The light-emitting device (e.g., the light-emitting device 1) of the present disclosure can also be applied to a head-mounted display (hereinafter referred to as an HMD). The head-mounted display 1130A can be used for virtual reality (VR), augmented reality (AR), mixed reality (MR), substitutional reality (SR), or the like.

[0129] 20A is a perspective view showing the appearance of a head-mounted display (electronic device) 1130A. The head-mounted display 1130A has, for example, ear hooks 1131 on both sides of a glasses-shaped display unit 1132 for wearing on the user's head. The display unit 1132 is equipped with a light-emitting device 1.

[0130] FIG. 20B is a perspective view showing the appearance of another head-mounted display (electronic device). The head-mounted display is smart glasses 1130B that display various information on glasses 1133. The smart glasses 1130B include a main body, an arm 1135, and a lens barrel 1136. The main body 1134 is connected to the arm 1135. The main body 1134 is detachable from the glasses 1133. The main body 1134 incorporates a control board and a display unit for controlling the operation of the smart glasses 1130B. The main body 1134 and the lens barrel 1136 are connected to each other via the arm 1135. The lens barrel 1136 emits image light emitted from the main body 1134 via the arm 1135 toward the lenses 1137 of the glasses 1133. This image light enters the human eye through the lens 1137. 28B, a wearer of the smart glasses 1130B can visually recognize not only the surrounding situation but also various pieces of information emitted from the lens barrel 1136, as with normal glasses. The main body 1134 includes the light-emitting device 1.

[0131] 21 is a perspective view showing an example of the appearance of a television device (electronic device) 1140. This television device 1140 has, for example, an image display screen unit 1141 including a front panel 1142 and a filter glass 1143. The image display screen unit 1141 is equipped with the light-emitting device 1.

[0132] The present technology has been described above with reference to the first to fourth embodiments, modifications 1 to 10, and application examples, but the present technology is not limited to the above embodiments, etc., and various modifications are possible. For example, in the above embodiments, etc., examples have been shown in which the light emitted from the light-emitting element 11 is blue light or ultraviolet light, but the present technology is not limited to this. For example, the light-emitting device 1 may use a light-emitting element that emits two or more types of light, such as blue light and green light, or ultraviolet light and green light.

[0133] In addition, in the above-described embodiment, the light-emitting element (e.g., light-emitting element 11) has a substantially circular planar shape, but this is not limiting. The planar shape of light-emitting element 11 may be, for example, a polygonal shape including a substantially square, rectangular, hexagonal, or trapezoidal shape, or may be a circular shape including an ellipse.

[0134] Furthermore, in the above-described embodiment and the like, the side surfaces of the light-emitting element (e.g., light-emitting element 11) have a substantially vertical cross-sectional shape, e.g., a rectangular cross-section, but this is not limiting. For example, the light-emitting element 11 may have a side surface extending toward the light-emitting side (surface 11S1) that is inclined, e.g., a trapezoidal cross-sectional shape.

[0135] Furthermore, in the above embodiments, each component constituting the light emitting device 1 etc. has been specifically listed and described, but it is not necessary to include all components, and other components may also be included.

[0136] The effects described in this specification are merely examples and are not limited to those described, and other effects may also be obtained.

[0137] The present technology can also be configured as follows. According to the present technology configured as follows, it is possible to reduce damage to the upper surface of the second compound semiconductor layer due to process history while suppressing an increase in operating voltage due to a tunnel junction, thereby improving device characteristics. (1) A light-emitting device comprising: a first compound semiconductor layer of a first conductivity type; a second compound semiconductor layer of a second conductivity type; an active layer provided between the first compound semiconductor layer and the second compound semiconductor layer; a third compound semiconductor layer of the first conductivity type provided on a surface of the second compound semiconductor layer opposite to a surface facing the active layer; a first electrode electrically connected to the first compound semiconductor layer; and a second electrode embedded in the third compound semiconductor layer and electrically connected to the second compound semiconductor layer. (2) The light-emitting device according to (1), wherein the second electrode is in direct contact with the second compound semiconductor layer. (3) The light-emitting device according to (1) or (2), wherein a stack including the first compound semiconductor layer, the second compound semiconductor layer, the active layer, and the third compound semiconductor layer is enclosed in an insulating film. (4) The light-emitting device according to any one of (1) to (3), further comprising an opening penetrating the third compound semiconductor layer in the stacking direction, and the second electrode being embedded in the opening. (5) The light-emitting device according to any one of (1) to (4), wherein the second electrode has a pair of surfaces opposing each other in the stacking direction, one of the pair of surfaces being electrically connected to the second compound semiconductor layer, and the other of the pair of surfaces being connected to external wiring. (6) The light-emitting device according to any one of (1) to (5), wherein a contact area between the second compound semiconductor layer and the second electrode is smaller than a contact area between the second compound semiconductor layer and the third compound semiconductor layer. (7) The light-emitting device according to any one of (1) to (6), wherein the second electrode has a surface opposite to a surface in contact with the second compound semiconductor layer, the surface being covered with the third compound semiconductor layer. (8) The light-emitting device according to (7), wherein the second electrode is drawn out from a side surface of the third compound semiconductor layer to the outside.(9) The light-emitting device according to any one of (1) to (8), wherein the third compound semiconductor layer extends from on top of the second compound semiconductor layer to side surfaces of the second compound semiconductor layer, the active layer, and the first compound semiconductor layer. (10) The light-emitting device according to (9), wherein an undoped fourth compound semiconductor layer extends between the third compound semiconductor layer and an upper surface of the second compound semiconductor layer and side surfaces of the second compound semiconductor layer, the active layer, and the first compound semiconductor layer. (11) The light-emitting device according to (9), wherein an insulating film extends between the third compound semiconductor layer and an upper surface of the second compound semiconductor layer and side surfaces of the second compound semiconductor layer, the active layer, and the first compound semiconductor layer. (12) The light emitting device according to any one of (1) to (11), wherein the third compound semiconductor layer has a light extraction surface on an opposite side to a surface facing the second compound semiconductor layer, and further has a wavelength conversion portion above the light extraction surface that converts the wavelength of light emitted from the active layer. (13) The light emitting device according to any one of (1) to (12), wherein the third compound semiconductor layer has a light extraction surface on an opposite side to a surface facing the second compound semiconductor layer, and the light extraction surface has a photonic crystal structure. (14) The light emitting device according to any one of (1) to (13), wherein the third compound semiconductor layer has a light extraction surface on an opposite side to a surface facing the second compound semiconductor layer, and the light extraction surface has a lens shape. (15) The light-emitting device according to any one of (1) to (14), wherein the third compound semiconductor layer has a light extraction surface on the side opposite to a surface facing the second compound semiconductor layer, and the first electrode is provided on a surface of the first compound semiconductor layer opposite to the light extraction surface side.(16) The light-emitting device according to any one of (1) to (15), wherein the third compound semiconductor layer has a light extraction surface on the side opposite to the surface facing the second compound semiconductor layer, the first compound semiconductor layer extends outward beyond the active layer, the second compound semiconductor layer, and the third compound semiconductor layer in a planar view, and the first electrode is provided on the surface of the first compound semiconductor layer on the light extraction surface side. (17) The light-emitting device according to any one of (3) to (16), wherein the stack is made of III-V compound semiconductors. (18) The light-emitting device according to any one of (1) to (17), wherein the first compound semiconductor layer and the third compound semiconductor layer are n-type compound semiconductor layers, and the second compound semiconductor layer is a p-type compound semiconductor layer. (19) An image display device comprising a light-emitting device, the light-emitting device having: a first compound semiconductor layer of a first conductivity type; a second compound semiconductor layer of a second conductivity type; an active layer provided between the first compound semiconductor layer and the second compound semiconductor layer; a third compound semiconductor layer of the first conductivity type provided on a surface of the second compound semiconductor layer opposite to a surface facing the active layer; a first electrode electrically connected to the first compound semiconductor layer; and a second electrode embedded in the third compound semiconductor layer and electrically connected to the second compound semiconductor layer. (20) A light emitting device comprising: a first compound semiconductor layer of a first conductivity type; a second compound semiconductor layer of a second conductivity type; an active layer provided between the first compound semiconductor layer and the second compound semiconductor layer; a first electrode electrically connected to the first compound semiconductor layer; a third compound semiconductor layer of the first conductivity type provided on the second compound semiconductor layer in contact with the second compound semiconductor layer and extending outward beyond the active layer, the second compound semiconductor layer, and the third compound semiconductor layer in a planar view; and a second electrode provided on the third compound semiconductor layer.(21) A light emitting device comprising: a first compound semiconductor layer of a first conductivity type; a second compound semiconductor layer of a second conductivity type; an active layer provided between the first compound semiconductor layer and the second compound semiconductor layer; a first electrode electrically connected to the first compound semiconductor layer; a third compound semiconductor layer of the first conductivity type provided on the second compound semiconductor layer in contact with the second compound semiconductor layer; and a second electrode provided on the third compound semiconductor layer and partially embedded in the third compound semiconductor layer up to the vicinity of the second compound semiconductor layer.

[0138] This application claims priority based on Japanese Patent Application No. 2024-048408, filed on March 25, 2024, in the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0139] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

1. A light emitting device comprising: a first compound semiconductor layer of a first conductivity type; a second compound semiconductor layer of a second conductivity type; an active layer provided between the first compound semiconductor layer and the second compound semiconductor layer; a third compound semiconductor layer of the first conductivity type provided on the surface of the second compound semiconductor layer opposite to the surface facing the active layer; a first electrode electrically connected to the first compound semiconductor layer; and a second electrode embedded in the third compound semiconductor layer and electrically connected to the second compound semiconductor layer.

2. The light emitting device according to claim 1, wherein the second electrode is in direct contact with the second compound semiconductor layer.

3. The light-emitting device according to claim 1, wherein a stack including the first compound semiconductor layer, the second compound semiconductor layer, the active layer, and the third compound semiconductor layer is enclosed by an insulating film.

4. The light emitting device according to claim 1, further comprising an opening penetrating said third compound semiconductor layer in the stacking direction, said second electrode being embedded in said opening.

5. The light-emitting device according to claim 1, wherein the second electrode has a pair of surfaces opposing each other in the stacking direction, one of the pair of surfaces being electrically connected to the second compound semiconductor layer, and the other of the pair of surfaces being connected to external wiring.

6. The light emitting device according to claim 1, wherein the contact area between said second compound semiconductor layer and said second electrode is smaller than the contact area between said second compound semiconductor layer and said third compound semiconductor layer.

7. The light emitting device according to claim 1, wherein the second electrode has a surface opposite to the surface in contact with the second compound semiconductor layer that is covered with the third compound semiconductor layer.

8. The light emitting device according to claim 7, wherein the second electrode is extended to the outside from a side surface of the third compound semiconductor layer.

9. The light-emitting device according to claim 1, wherein the third compound semiconductor layer extends from above the second compound semiconductor layer to side surfaces of the second compound semiconductor layer, the active layer, and the first compound semiconductor layer.

10. The light-emitting device according to claim 9, wherein an undoped fourth compound semiconductor layer extends between the third compound semiconductor layer and the top surface of the second compound semiconductor layer and the side surfaces of the second compound semiconductor layer, the active layer, and the first compound semiconductor layer.

11. The light-emitting device according to claim 9, wherein an insulating film extends between the third compound semiconductor layer and the top surface of the second compound semiconductor layer, as well as between the second compound semiconductor layer, the active layer, and the side surfaces of the second compound semiconductor layer, the active layer, and the first compound semiconductor layer.

12. The light-emitting device according to claim 1, wherein the third compound semiconductor layer has a light extraction surface on the side opposite to the surface facing the second compound semiconductor layer, and further has a wavelength conversion section above the light extraction surface that converts the wavelength of light emitted from the active layer.

13. The light emitting device according to claim 1, wherein the third compound semiconductor layer has a light extraction surface on the side opposite to the surface facing the second compound semiconductor layer, and the light extraction surface has a photonic crystal structure.

14. The light emitting device according to claim 1, wherein the third compound semiconductor layer has a light extraction surface on the side opposite to the surface facing the second compound semiconductor layer, and the light extraction surface has a lens shape.

15. The light-emitting device described in claim 1, wherein the third compound semiconductor layer has a light extraction surface on the side opposite to the surface facing the second compound semiconductor layer, and the first electrode is provided on the surface of the first compound semiconductor layer opposite to the light extraction surface side.

16. The light-emitting device according to claim 1, wherein the third compound semiconductor layer has a light extraction surface on the side opposite to the surface facing the second compound semiconductor layer, the first compound semiconductor layer extends outward beyond the active layer, the second compound semiconductor layer, and the third compound semiconductor layer in a planar view, and the first electrode is provided on the surface of the first compound semiconductor layer facing the light extraction surface.

17. The light emitting device according to claim 3, wherein the laminate is made of a III-V compound semiconductor.

18. The light-emitting device according to claim 1, wherein the first compound semiconductor layer and the third compound semiconductor layer are n-type compound semiconductor layers, and the second compound semiconductor layer is a p-type compound semiconductor layer.

19. An image display device comprising a light-emitting device, the light-emitting device having: a first compound semiconductor layer of a first conductivity type; a second compound semiconductor layer of a second conductivity type; an active layer provided between the first compound semiconductor layer and the second compound semiconductor layer; a third compound semiconductor layer of the first conductivity type provided on the surface of the second compound semiconductor layer opposite to the surface facing the active layer; a first electrode electrically connected to the first compound semiconductor layer; and a second electrode embedded in the third compound semiconductor layer and electrically connected to the second compound semiconductor layer.

Images