Light-emitting element

Abstract

To provide a light emitting element having a configuration and a structure that hardly cause optical loss at an interface between a first light reflecting layer and a laminated structure.SOLUTION: Included are a first light reflecting layer 41, a laminated structure 20, and a second light reflecting layer 42 laminated to each other. The laminated structure 20 includes a first compound semiconductor layer 21, a light emitting layer 23, and a second compound semiconductor layer 22 laminated to each other from a side of the first light reflecting layer. Light from the laminated structure 20 is emitted to an outside via the first light reflecting layer 41 or the second light reflecting layer 42. The first light reflecting layer 41 has a structure in which at least two types of thin films 41A and 41B are alternately laminated to each other in plural numbers. A film thickness modulating layer 80 is provided between the laminated structure 20 and the first light reflecting layer 41.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a light-emitting element.

Background Art

[0002] In a light-emitting device composed of a surface-emitting laser element (VCSEL), laser oscillation usually occurs by resonating laser light between two light reflection layers (Distributed Bragg Reflector layers, DBR layers). In such a light-emitting device, for example, a first light reflection layer formed by laminating a plurality of thin films on the exposed surface of a substrate is formed, and from above the exposed surface of the substrate on which the first light reflection layer is not formed to above the first light reflection layer, a method of epitaxial lateral growth such as the ELO (Epitaxial Lateral Overgrowth) method is used to form a laminated structure in which a first compound semiconductor layer, a light-emitting layer (active layer) composed of a compound semiconductor, and a second compound semiconductor layer are laminated (for example, see T. Hamaguchi, et al., "Milliwatt-class GaN-based blue vertical-cavity surface-emitting lasers fabricated by epitaxial lateral overgrowth", Phys. Status Solidi A, 1-7 (2016) / DOI 10.1002 / pssa.201532759). Then, a second electrode made of a transparent conductive material is formed on the second compound semiconductor layer, and a second light reflection layer composed of a laminated structure of thin films is formed on the second electrode. Alternatively, after forming the laminated structure, the second electrode, and the second light reflection layer on the substrate, for example, the substrate is removed based on the CMP method (chemical / mechanical polishing method), and a first light reflection layer formed by laminating a plurality of thin films is formed on the exposed first compound semiconductor layer (for example, see Japanese Patent Application Laid-Open No. 2011-151364).Alternatively, a first optical reflection layer formed by laminating thin films of a plurality of compound semiconductors on a substrate is formed based on an epitaxial growth method, and a stacked structure, a second electrode, and a second optical reflection layer are further formed on the first optical reflection layer (for example, see Tien-Chang Lu, et al., "Continuous wave operation of current injected GaN vertical cavity surface emitting lasers at room temperature", Appl. Phys. Lett. 97, 071114 (2010); doi: 10.1063 / 1.3483133).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in any of these methods, when forming the first light reflection layer or the stacked structure, it may be difficult to keep the state of the interface between the first light reflection layer and the stacked structure good. And when the state of the interface cannot be kept good, the light generated in the light emitting layer (active layer) may be absorbed or scattered, that is, it becomes the cause of optical loss. As a result, there is a risk of an increase in the threshold value of the light emitting element, a decrease in the light emitting efficiency, and a deterioration in the quality of the emitted light.

[0006] Therefore, an object of the present disclosure is to provide a light emitting element having a configuration and a structure in which optical loss hardly occurs at the interface between the first light reflection layer and the stacked structure.

Means for Solving the Problems

[0007] The light emitting element of the present disclosure for achieving the above object is formed by laminating a first light reflection layer, a stacked structure, and a second light reflection layer, The stacked structure is formed by laminating a first compound semiconductor layer, a light emitting layer, and a second compound semiconductor layer from the first light reflection layer side, The light from the stacked structure is emitted to the outside through the first light reflection layer or the second light reflection layer, The first light reflection layer has a structure in which a plurality of at least two types of thin films are alternately laminated, A film thickness modulation layer is provided between the stacked structure and the first light reflection layer, The first light reflection layer and the film thickness modulation layer have a concave mirror portion The second light reflection layer has a flat shape, In the second compound semiconductor layer, a current injection region and a current non-injection region surrounding the current injection region are provided, The shortest distance D from the area centroid point of the current injection region to the boundary between the current injection region and the current non-injection region CI satisfies the following formula. D CI ≧ω 0 / 2 However, ω 0 2 ≡(λ 0 / π){L OR (R DBR -L OR )} 1 / 2 Here, λ 0 : The wavelength of the light mainly emitted from the light-emitting element L OR : The resonator length R DBR : The radius of curvature of the concave mirror portion composed of the first light reflection layer and the film thickness modulation layer

Advantages of the Invention

[0008] In the light-emitting element of the present disclosure, since the film thickness modulation layer is provided between the laminated structure and the first light reflection layer, optical loss is unlikely to occur in the region of the first light reflection layer facing the laminated structure or in the region of the laminated structure facing the first light reflection layer. Therefore, it is possible to surely avoid problems such as an increase in the threshold value of the light-emitting element, a decrease in the light-emitting efficiency, and a deterioration in the quality of the emitted light. Note that the effects described in this specification are merely examples and are not limited, and there may be additional effects.

Brief Description of the Drawings

[0009]

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BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, the present disclosure will be described based on embodiments with reference to the drawings. However, the present disclosure is not limited to the embodiments, and various numerical values and materials in the embodiments are illustrative. The description will be made in the following order. 1. General description of the light-emitting element of the present disclosure 2. Example 1 (light-emitting element of the present disclosure) 3. Example 2 (modification of Example 1) 4. Example 3 (another modification of Example 1) 5. Example 4 (modification of Examples 1 to 3, light-emitting element provided with a light absorption material layer) 6. Example 5 (modification of Example 4) 7. Example 6 (another modification of Example 4) 8. Example 7 (modification of Examples 1 to 6, light-emitting element having a concave mirror portion, light-emitting element of the 5-A configuration) 9. Example 8 (modification of Example 7, light-emitting element of the 5-B configuration) 10. Example 9 (modification of Examples 7 to 8, light-emitting element of the 6 configuration) 11. Example 10 (modification of Example 9) 12. Example 11 (modification of Examples 7 to 10, light-emitting element of the 1 configuration) 13. Example 12 (modification of Examples 7 to 11, light-emitting element of the 2-A configuration) 14. Example 13 (modification of Example 12, light-emitting element of the 2-B configuration) 15. Example 14 (modification of Examples 12 to 13, light-emitting element of the 2-C configuration) 16. Example 15 (modification of Examples 12 to 14, light-emitting element of the 2-D configuration) 17. Example 16 (modification of Examples 12 to 15) 18. Example 17 (modification of Examples 7 to 11, light-emitting elements of the 3-A configuration, 3-B configuration, 3-C configuration, and 3-D configuration) 19. Example 18 (modification of Examples 7 to 17, light-emitting element of the 4 configuration) 20. Others

[0011] 〈General description of the light-emitting element of the present disclosure〉 In the light-emitting element of the present disclosure, the first light reflection layer has an optical film thickness t1 a first thin film having 2 (where t 2 ≠t 1 ) and a plurality of second thin films are alternately laminated; the film thickness modulation layer includes at least one third thin film having an optical film thickness t 3 (where t 3 ≠t 1 ). In this case, as the degree of film thickness modulation, t 3 / t 1 ≧1.1, preferably, 1.9≧t 3 / t 1 ≧1.1 is satisfied, or t 3 / t 1 ≦0.9, preferably, 0.1≦t 3 / t 1 ≦0.9 is desirably satisfied.

[0012] Here, the optical film thickness is expressed as n phys ×t 0 when the physical thickness of the thin film is t 0 , the refractive index of the material constituting the thin film at the oscillation wavelength (emission wavelength) λ 0 of the light emitting element is n phys . If the material constituting the thin film changes, the value of the refractive index n 0 changes. However, even if the material constituting the thin film is the same (for example, the elements constituting the thin film are the same), the value of the refractive index n 0 can be changed by changing the composition, or the value of the refractive index n 0 can also be changed by adding impurities or the like to the material constituting the thin film. Materials having different refractive indices n 0 are referred to as "mutually different materials" in this application.

[0013] And in each of the above-described preferred forms, the first thin film is made of a first material; the second thin film can be made of a second material different from the first material.

[0014] Furthermore, in the preferred form described above, the film thickness modulation layer includes a third thin film and an optical film thickness t4 It can be configured to have a structure in which a fourth thin film having 3 ≠t 1 is laminated. Furthermore, in this case, the film thickness modulation layer has a structure in which a plurality of the third thin films and the fourth thin films are alternately laminated; among the third thin films, the optical film thickness of at least one layer is t 4 ≠t 2 is satisfied, and furthermore, in this case, among the fourth thin films, the optical film thickness of at least one layer is t 3 ≠t 1 is satisfied, and furthermore, in this case, the third thin film that satisfies t 4 ≠t 2 or the fourth thin film that satisfies t 3 ≠t 1 can be in contact with the first light reflection layer. Furthermore, in these configurations, the third thin films other than the third thin film that satisfies t 3 =t 1 are satisfied; the fourth thin films other than the fourth thin film that satisfies t 4 ≠t 2 can be in a configuration that satisfies t 4 =t 2 Furthermore, in these configurations, the total number of layers of the third thin film and the fourth thin film can be 5 or less. Furthermore, in these configurations, the third thin film can be made of the first material; the fourth thin film can be made of the second material.

[0015] In the light-emitting element of the present disclosure including the preferred forms described above, the first light reflection layer can be configured to be formed on the substrate. In this case, a stacked structure can be formed on the region of the substrate where the first light reflection layer is not formed.

[0016] Alternatively, in the preferred forms described above, the first light reflection layer can be configured to be formed on the exposed surface of the stacked structure.

[0017] Alternatively, in the preferred embodiments described above, the first material can be composed of a compound semiconductor material, and the second material can also be composed of a compound semiconductor material. In the preferred embodiments and configurations described above, the first material can be composed of a dielectric material, and the second material can also be composed of a dielectric material. However, the material constituting the film thickness modulation layer may be different from the materials constituting the first compound semiconductor layer, the light emitting layer, and the second compound semiconductor layer.

[0018] Furthermore, in the light emitting device of the present disclosure including the preferred embodiments and configurations described above, the first light reflecting layer has a concave mirror portion, the second light reflecting layer can have a flat shape.

[0019] Furthermore, in the light emitting device of the present disclosure including the preferred embodiments and configurations described above, the thickness of the first compound semiconductor layer can be greater than the thickness of the second compound semiconductor layer.

[0020] Furthermore, in the light emitting device of the present disclosure including the preferred embodiments and configurations described above, the laminated structure can be composed of a GaN-based compound semiconductor.

[0021] Furthermore, in the light-emitting element of the present disclosure including the preferred forms and configurations described above, irregular structures (for example, fine unevenness, point defects, line defects, voids, etc.) may exist at or near the interface between the film thickness modulation layer and the first light reflection layer. Here, the irregular structure may be formed in the film thickness modulation layer, or may be formed in the first light reflection layer, or may be formed across the film thickness modulation layer and the first light reflection layer. Still, these three cases are collectively referred to as "irregular structures are formed at the interface between the film thickness modulation layer and the first light reflection layer". Specifically, in the light-emitting element of the present disclosure including the preferred forms and configurations described above, unevenness is formed at the interface between the laminated structure and the film thickness modulation layer, and the root mean square roughness Rq of the surface of the unevenness is in the form of Rq≧1 nm. Still, as the upper limit value of Rq, although not limited, 10 nm can be mentioned. Alternatively, in the light-emitting element of the present disclosure including the preferred forms and configurations described above, point defects are formed at the interface between the laminated structure and the film thickness modulation layer, and the density of the point defects is 1×10 17 / cm 3 or more. Still, as the upper limit value of the density of the point defects, although not limited, 1×10 19 / cm 3 can be mentioned. Alternatively, in the light-emitting element of the present disclosure including the preferred forms and configurations described above, line defects are formed at the interface between the laminated structure and the film thickness modulation layer, and as the density of the line defects, 1×10 6 / cm 3 or more can be exemplified. Still, as the upper limit value of the density of the line defects, although not limited, 1×10 11 / cm 3 can be mentioned. Alternatively, in the light-emitting element of the present disclosure including the preferred forms and configurations described above, voids are formed at the interface between the laminated structure and the film thickness modulation layer, and the thickness of the voids [the maximum thickness of the voids] (the maximum separation distance between the laminated structure and the film thickness modulation layer) can be in the form of 10 nm or less. Still, as the lower limit value of the thickness of the voids [the maximum thickness of the voids], although not limited, 0.2 nm can be mentioned. As the structure of the voids, a structure in which the voids are filled with gas or liquid can be exemplified.

[0022] In the following description, the surface of the first compound semiconductor layer facing the light-emitting layer (active layer) is referred to as the second surface, and the surface facing the second surface is referred to as the first surface. Also, the surface of the second compound semiconductor layer facing the light-emitting layer is referred to as the first surface, and the surface facing the first surface is referred to as the second surface. In the substrate for manufacturing a light-emitting device described later, the surface facing the first compound semiconductor layer is referred to as the second surface, and the surface facing the second surface is referred to as the first surface.

[0023] With the light-emitting device of the present disclosure including the preferred forms and configurations described above, a surface-emitting laser device (vertical cavity laser, VCSEL) that emits laser light through the first light reflection layer can be configured, or alternatively, a surface-emitting laser device that emits laser light through the second light reflection layer can also be configured. Note that, depending on the configuration and structure of the light-emitting device, in some cases, the substrate for manufacturing a light-emitting device described later may be removed.

[0024] As described above, the light reflection layers (distributed Bragg reflector layers, DBR layers) constituting the first light reflection layer and the second light reflection layer are composed of, for example, a compound semiconductor material multilayer film or a dielectric material multilayer film. Examples of the compound semiconductor material include GaN, AlInN, and AlGaN, and examples of the dielectric material include oxides such as Si, Mg, Al, Hf, Nb, Zr, Sc, Ta, Ga, Zn, Y, B, and Ti, nitrides (for example, SiN X , AlN X , AlGaN X , GaN X , BN X , etc.), or fluorides. Specifically, SiO X , TiO X , NbO X , ZrO X , TaO X , ZnO X , AlO X , HfO X , SiN X , AlN XExamples thereof include the following. By alternately laminating two or more compound semiconductor material films or dielectric material films made of compound semiconductor materials or dielectric materials having different refractive indices among these compound semiconductor materials and dielectric materials, a light reflection layer can be obtained. For example, multilayers such as GaN / AlInN, SiO X / SiN Y 、SiO X / TaO X 、SiO X / NbO Y 、SiO X / ZrO Y 、SiO X / AlN Y are preferable. In order to obtain a desired light reflectance, the materials, film thicknesses, number of layers, etc. constituting each compound semiconductor material film or dielectric material film may be appropriately selected. The thickness (optical film thickness) of each compound semiconductor material film or dielectric material film can be appropriately adjusted according to the materials used, etc., and is determined by the oscillation wavelength (emission wavelength) λ 0 and the refractive index n at the oscillation wavelength λ 0 of the material used. Specifically, it is preferably an odd multiple of λ 0 / (4n). For example, in a light-emitting element with an oscillation wavelength λ 0 of 410 nm, when the light reflection layer is composed of SiO X / NbO Y , about 40 nm to 70 nm can be exemplified. The number of layers can be exemplified as 2 or more, preferably about 10 to 30. As the thickness of the entire light reflection layer, for example, about 0.6 μm to 1.7 μm can be exemplified. Also, the light reflectance of the light reflection layer is desirably 95% or more.

[0025] The light reflection layer composed of a dielectric material multilayer film can be formed based on well-known methods. Specifically, for example, PVD methods such as vacuum evaporation method, sputtering method, reactive sputtering method, ECR plasma sputtering method, magnetron sputtering method, ion beam assisted deposition method, ion plating method, laser ablation method, etc.; various CVD methods; coating methods such as spray method, spin coating method, dip method, etc.; methods combining two or more of these methods; methods combining these methods with any one or more of overall or partial pretreatment, irradiation with inert gas (Ar, He, Xe, etc.) or plasma, irradiation with oxygen gas or ozone gas or plasma, oxidation treatment (heat treatment), exposure treatment, etc. can be mentioned. The light reflection layer composed of a compound semiconductor material multilayer film can also be formed based on well-known methods. Specifically, formation methods of various compound semiconductor layers described later can be mentioned.

[0026] The light reflection layer is not particularly limited in size and shape as long as it covers the element region (current injection region). Specific examples of the shape of the boundary between the current injection region and the non-current injection / inner region, the shape of the boundary between the non-current injection / inner region and the non-current injection / outer region, the planar shape of the opening provided in the element region or the current constriction region, the planar shape of the opening provided in the first light reflection layer, the second light reflection layer, and the current constriction layer include a circle, an ellipse, a rectangle, and a polygon (such as a triangle, a quadrilateral, a hexagon, etc.). In addition, an annular shape can be cited as the planar shape of the first electrode. The shape of the boundary between the current injection region and the non-current injection / inner region, the shape of the boundary between the non-current injection / inner region and the non-current injection / outer region, the planar shape of the opening provided in the element region, the first light reflection layer, the second light reflection layer, the current constriction layer, and the planar shape of the inner annular portion of the annular first electrode are preferably similar shapes. When these planar shapes are circular, the diameter is preferably about 5 μm to 100 μm. Note that the "element region (current injection region)" refers to a region into which a narrowed current is injected, or a region in which light is confined due to a refractive index difference or the like, or a region in which laser oscillation occurs within the region sandwiched between the first light reflection layer and the second light reflection layer, or a region that actually contributes to laser oscillation within the region sandwiched between the first light reflection layer and the second light reflection layer. The element region (current injection region) is surrounded by a non-current injection region, and the current constriction region is defined by the element region (current injection region) and the non-current injection region.

[0027] To obtain a current constriction region, an insulating layer (current constriction layer) made of an insulating material (for example, SiO X or SiN X , AlO X ) may be formed between the second electrode and the second compound semiconductor layer, or the second compound semiconductor layer may be etched by an RIE method or the like to form a mesa structure, or a part of the stacked second compound semiconductor layer may be partially oxidized laterally to form a current constriction region, or impurities may be ion-implanted into the second compound semiconductor layer to form a region with reduced conductivity, or these may be appropriately combined. However, the second electrode needs to be electrically connected to the portion of the second compound semiconductor layer through which current flows due to current constriction.

[0028] In the light-emitting device of the present disclosure, the stacked structure can specifically be configured of an AlInGaN-based compound semiconductor. Here, examples of the AlInGaN-based compound semiconductor include GaN, AlGaN, InGaN, and AlInGaN. Further, these compound semiconductors may contain boron (B) atoms, thallium (Tl) atoms, arsenic (As) atoms, phosphorus (P) atoms, or antimony (Sb) atoms as desired. The light-emitting layer desirably has a quantum well structure. Specifically, it may have a single quantum well structure (SQW structure) or a multiple quantum well structure (MQW structure). The light-emitting layer having a quantum well structure has a structure in which at least one well layer and one barrier layer are stacked. As combinations of (the compound semiconductor constituting the well layer, the compound semiconductor constituting the barrier layer), (In y Ga (1-y) N,GaN), (In y Ga (1-y) N,In z Ga (1-z) N) [where y > z], (In y Ga (1-y) N,Al x Ga 1-x N), (GaN,Al x Ga 1-x N) can be exemplified. The first compound semiconductor layer can be composed of a compound semiconductor of a first conductivity type (e.g., n-type), and the second compound semiconductor layer can be composed of a compound semiconductor of a second conductivity type different from the first conductivity type (e.g., p-type). The first compound semiconductor layer and the second compound semiconductor layer are also referred to as the first cladding layer and the second cladding layer. The first compound semiconductor layer and the second compound semiconductor layer may be a single-structured layer, a multi-layered structure layer, or a superlattice structure layer. Further, it can also be a layer provided with a composition gradient layer or a concentration gradient layer.

[0029] As methods for forming various compound semiconductor layers constituting a light-emitting element, for example, metalorganic chemical vapor deposition (MOCVD method, Metal Organic-Chemical Vapor Deposition method, MOVPE method, Metal Organic-Vapor Phase Epitaxy method), molecular beam epitaxy (MBE method), hydride vapor phase epitaxy (HVPE method) in which halogen contributes to transport or reaction, atomic layer deposition (ALD method, Atomic Layer Deposition method), migration-enhanced epitaxy (MEE method, Migration-Enhanced Epitaxy method), plasma-assisted physical vapor deposition (PPD method), etc. can be mentioned, but it is not limited to these.

[0030] Here, as the organic gallium source gas in the MOCVD method, trimethylgallium (TMG) gas or triethylgallium (TEG) gas can be mentioned, and as the nitrogen source gas, ammonia gas or hydrazine gas can be mentioned. In the formation of a GaN-based compound semiconductor layer having an n-type conductivity type, for example, silicon (Si) may be added as an n-type impurity (n-type dopant), and in the formation of a GaN-based compound semiconductor layer having a p-type conductivity type, for example, magnesium (Mg) may be added as a p-type impurity (p-type dopant). When aluminum (Al) or indium (In) is included as a constituent atom of the GaN-based compound semiconductor layer, trimethylaluminum (TMA) gas may be used as the Al source, and trimethylindium (TMI) gas may be used as the In source. Furthermore, monosilane gas (SiH 4 gas) may be used as the Si source, and biscyclopentadienylmagnesium gas, methylcyclopentadienylmagnesium, biscyclopentadienylmagnesium (Cp 2 Mg) may be used as the Mg source. In addition, as n-type impurities (n-type dopants), Ge, Se, Sn, C, Te, S, O, Pd, Po can be mentioned in addition to Si, and as p-type impurities (p-type dopants), Zn, Cd, Be, Ca, Ba, C, Hg, Sr can be mentioned in addition to Mg.

[0031] The surface roughness Ra of the second compound semiconductor layer (the second surface of the second compound semiconductor layer) is preferably 1.0 nm or less. The surface roughness Ra or the surface roughness Rq is defined in JIS B-610:2001, and specifically, it can be measured based on observations by AFM or cross-sectional TEM.

[0032] The light-emitting element of the present disclosure includes a first electrode and a second electrode. The first electrode is electrically connected to the first compound semiconductor layer. Further, the second electrode is electrically connected to the second compound semiconductor layer, and specifically, for example, it is formed on the second surface of the second compound semiconductor layer.

[0033] When the substrate for manufacturing the light-emitting element remains, the first electrode may be formed on the first surface of the substrate for manufacturing the light-emitting element. When the substrate for manufacturing the light-emitting element does not remain, it may be formed on the first surface of the first compound semiconductor layer constituting the laminated structure. When the first electrode is formed on the first surface of the first compound semiconductor layer, for example, the first electrode may be formed so as to surround the first light reflection layer. The first electrode preferably contains at least one metal (including an alloy) selected from the group consisting of gold (Au), silver (Ag), palladium (Pd), platinum (Pt), nickel (Ni), Ti (titanium), vanadium (V), tungsten (W), chromium (Cr), aluminum (Al), copper (Cu), zinc (Zn), tin (Sn), and indium (In), and has a single-layer structure or a multilayer structure. Specifically, for example, Ti / Au, Ti / Al, Ti / Al / Au, Ti / Pt / Au, Ni / Au, Ni / Au / Pt, Ni / Pt, Pd / Pt, Ag / Pd can be exemplified. In the multilayer structure, the layer before " / " is located closer to the light-emitting layer side. The same applies in the following description. The first electrode can be formed by a PVD method such as a vacuum evaporation method or a sputtering method.

[0034] When forming the first electrode so as to surround the first light reflection layer, the first light reflection layer and the first electrode can be configured to be in contact with each other. Alternatively, the first light reflection layer and the first electrode may be spaced apart, that is, have an offset, and the spacing distance can be configured to be within 1 mm. When the element region (current injection region) located in the first light reflection layer and the first electrode are planar-ly separated, the current will flow a long distance in the first compound semiconductor layer. Therefore, in order to keep the electrical resistance generated in this current path low, it is preferable that the spacing distance is within 1 mm. In some cases, a state where the first electrode is formed up to the edge of the first light reflection layer and a state where the first light reflection layer is formed up to the edge of the first electrode can also be mentioned. Here, when the first light reflection layer is formed up to the edge of the first electrode, the first electrode needs to have an opening of a certain size so as not to absorb the fundamental mode light of laser oscillation as much as possible. Since the size of the opening varies depending on the wavelength of the fundamental mode and the light confinement structure in the lateral direction (in-plane direction of the first compound semiconductor layer), it is not limited, but is approximately the oscillation wavelength (emission wavelength) λ 0 and preferably on the order of several times or more thereof.

[0035] The second electrode can be configured of a transparent conductive material. As the transparent conductive material constituting the second electrode, indium-based transparent conductive materials [specifically, for example, indium-tin oxide (ITO, Indium Tin Oxide, Sn-doped In 2 O 3 , including crystalline ITO and amorphous ITO), indium-zinc oxide (IZO, Indium Zinc Oxide), indium-gallium oxide (IGO), indium-doped gallium-zinc oxide (IGZO, In-GaZnO 4 ), IFO (F-doped In 2 O 3 ), ITiO (Ti-doped In 2 O 3 ), InSn, InSnZnO], tin-based transparent conductive materials [specifically, for example, tin oxide (SnO 2 ), ATO (Sb-doped SnO 2) FTO (F-doped SnO 2 )], zinc-based transparent conductive materials [specifically, for example, zinc oxide (including ZnO, Al-doped ZnO (AZO), and B-doped ZnO), gallium-doped zinc oxide (GZO), AlMgZnO (zinc oxide doped with aluminum oxide and magnesium oxide)], NiO can be exemplified. Alternatively, as the second electrode, a transparent conductive film having a gallium oxide, titanium oxide, niobium oxide, antimony oxide, nickel oxide, etc. as a mother layer can be mentioned, and a transparent conductive material such as a spinel-type oxide, YbFe 2 O 4 Structural oxides can also be mentioned. However, the material constituting the second electrode depends on the arrangement state of the second light reflection layer and the second electrode, and is not limited to a transparent conductive material, and metals such as palladium (Pd), platinum (Pt), nickel (Ni), gold (Au), cobalt (Co), and rhodium (Rh) can also be used. The second electrode may be composed of at least one of these materials. The second electrode can be formed by a PVD method such as a vacuum evaporation method or a sputtering method. Alternatively, a low-resistance semiconductor layer can be used as the transparent electrode layer. In this case, specifically, an n-type GaN-based compound semiconductor layer can also be used. Furthermore, when the layer adjacent to the n-type GaN-based compound semiconductor layer is p-type, the electrical resistance at the interface can be reduced by joining the two through a tunnel junction. Since the transparent conductive material and the tunnel junction also function as a light absorption material layer, they are not only effective in controlling the oscillation wavelength (specifically, as will be described later, among the plurality of types of longitudinal mode laser lights that can be emitted from the surface-emitting laser element, the oscillation of the undesired longitudinal mode laser light can be suppressed, and as a result, the oscillation wavelength of the emitted laser light can be accurately controlled), but there is also an additional effect that an electrical path (current path) can be used in combination.

[0036] By forming the second electrode from a transparent conductive material, the current can be spread in the lateral direction (in-plane direction of the second compound semiconductor layer), and the current can be efficiently supplied to the element region (current injection region). The second electrode is formed on the second surface of the second compound semiconductor layer, and it is preferable that a second light reflection layer is formed on the second electrode.

[0037] Pad electrodes may be provided on the first electrode or the second electrode for electrical connection to an external electrode or circuit. The pad electrode desirably has a single-layer structure or a multi-layer structure containing at least one metal selected from the group consisting of Ti (titanium), aluminum (Al), Pt (platinum), Au (gold), Ni (nickel), and Pd (palladium). Alternatively, the pad electrode can be a multi-layer structure exemplified by a Ti / Pt / Au multi-layer structure, a Ti / Au multi-layer structure, a Ti / Pd / Au multi-layer structure, a Ti / Ni / Au multi-layer structure, or a Ti / Ni / Au / Cr / Au multi-layer structure. When the first electrode is composed of an Ag layer or an Ag / Pd layer, a cover metal layer composed of, for example, Ni / TiW / Pd / TiW / Ni is formed on the surface of the first electrode, and a pad electrode composed of, for example, a Ti / Ni / Au multi-layer structure or a Ti / Ni / Au / Cr / Au multi-layer structure is preferably formed on the cover metal layer.

[0038] The laminated structure is formed on the second surface of the substrate for manufacturing a light-emitting element. As the substrate for manufacturing a light-emitting element, GaN substrate, GaAs substrate, sapphire substrate, SiC substrate, alumina substrate, ZnS substrate, ZnO substrate, AlN substrate, LiMgO substrate, LiGaO 2 substrate, MgAl 2 O 4Examples of substrates include InP substrates, Si substrates, and those with an underlayer or buffer layer formed on the surface (main surface) of these substrates. However, the use of GaN substrates is preferred because of their low defect density. Also, when finally leaving the substrate for manufacturing the light-emitting element, examples of such substrates for manufacturing the light-emitting element include compound semiconductor substrates such as GaN substrates and GaAs substrates, SiC substrates, and Si substrates. It is known that the characteristics of GaN substrates change depending on the growth surface, such as polar / non-polar / semi-polar. However, any main surface (second surface) of the GaN substrate can be used for forming the compound semiconductor layer. Regarding the main surface of the GaN substrate, depending on the crystal structure (e.g., cubic crystal type, hexagonal crystal type, etc.), crystal orientation planes called the so-called A plane, B plane, C plane, R plane, M plane, N plane, S plane, etc., or planes offset from these in a specific direction can also be used.

[0039] In the manufacture of the light-emitting element of the present disclosure, the substrate for manufacturing the light-emitting element may be left as it is, or after sequentially forming a light-emitting layer, a second compound semiconductor layer, a second electrode, and a second light reflection layer on the first compound semiconductor layer, the substrate for manufacturing the light-emitting element may be removed. Specifically, a light-emitting layer, a second compound semiconductor layer, a second electrode, and a second light reflection layer are sequentially formed on the first compound semiconductor layer. Then, after fixing the second light reflection layer to the support substrate, the substrate for manufacturing the light-emitting element is removed to expose the first compound semiconductor layer (the first surface of the first compound semiconductor layer). The removal of the substrate for manufacturing the light-emitting element can be performed by a wet etching method using an alkaline aqueous solution such as an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution, an ammonia solution + hydrogen peroxide water, a sulfuric acid solution + hydrogen peroxide water, a hydrochloric acid solution + hydrogen peroxide water, a phosphoric acid solution + hydrogen peroxide water, etc., a chemical mechanical polishing method (CMP method), a mechanical polishing method, a dry etching method, a lift-off method using a laser, etc., or a combination of these. As a result, the first compound semiconductor layer (the first surface of the first compound semiconductor layer) and the first light reflection layer are exposed.

[0040] Alternatively, when removing the substrate for manufacturing a light-emitting element, for example, a first light reflection layer, a film thickness modulation layer, and a first compound semiconductor layer are formed on the substrate for manufacturing a light-emitting element, and after sequentially forming a light-emitting layer, a second compound semiconductor layer, a second electrode, and a second light reflection layer on the first compound semiconductor layer, the substrate for manufacturing a light-emitting element may be removed using the first light reflection layer as a stopper layer. Specifically, for example, a first light reflection layer, a film thickness modulation layer, and a first compound semiconductor layer are formed on the substrate for manufacturing a light-emitting element, and a light-emitting layer, a second compound semiconductor layer, a second electrode, and a second light reflection layer are sequentially formed on the first compound semiconductor layer. Then, after fixing the second light reflection layer to the support substrate, the substrate for manufacturing a light-emitting element is removed using the first light reflection layer as a stopper layer to expose the first compound semiconductor layer (the first surface of the first compound semiconductor layer) and the first light reflection layer. Further, a first electrode may be formed on the first compound semiconductor layer (the first surface of the first compound semiconductor layer). Alternatively, the removal amount may be controlled based on the removal rate (polishing rate) of the substrate for manufacturing a light-emitting element, and it is not necessary to use a stopper layer.

[0041] The support substrate may be composed of, for example, various substrates exemplified as the substrate for manufacturing a light-emitting element, or alternatively, an insulating substrate made of AlN or the like, a semiconductor substrate made of Si, SiC, Ge or the like, a metal substrate or an alloy substrate. However, it is preferable to use a conductive substrate, or alternatively, it is preferable to use a metal substrate or an alloy substrate from the viewpoints of mechanical properties, elastic deformation, plastic deformability, heat dissipation, etc. As the thickness of the support substrate, for example, 0.05 mm to 1 mm can be exemplified. As a method for fixing the second light reflection layer to the support substrate, known methods such as a soldering method, a room temperature bonding method, a bonding method using an adhesive tape, a bonding method using wax bonding, and a method using an adhesive can be used. However, from the viewpoint of ensuring conductivity, it is desirable to adopt a soldering method or a room temperature bonding method. For example, when using a silicon semiconductor substrate, which is a conductive substrate, as the support substrate, it is desirable to adopt a method capable of bonding at a low temperature of 400 °C or lower in order to suppress warping due to the difference in the coefficient of thermal expansion. When using a GaN substrate as the support substrate, the bonding temperature may be 400 °C or higher.

[0042] The side surfaces and exposed surfaces of the laminated structure may be covered with a coating layer (insulating film). The formation of the coating layer can be carried out based on well-known methods. The refractive index of the material constituting the coating layer is preferably smaller than the refractive index of the material constituting the laminated structure. As the insulating material constituting the coating layer, SiO 2 containing SiO X -based materials, SiN X -based materials, SiO X N Z -based materials, TaO X , ZrO X , AlN X , AlO X , GaO X can be exemplified, or alternatively, organic materials such as polyimide resin can also be mentioned. As the method for forming the coating layer, for example, PVD methods such as vacuum evaporation method and sputtering method, or CVD method can be mentioned, and it can also be formed based on a coating method.

Example

[0043] Example 1 relates to the light-emitting element of the present disclosure. The light-emitting elements of Example 1 or Examples 2 to 18 described later are, depending on the structure, more specifically, surface-emitting laser elements (vertical cavity lasers, VCSELs) that emit laser light from the top surface of the second compound semiconductor layer through the second light reflection layer, or alternatively, surface-emitting laser elements (vertical cavity lasers, VCSELs) that emit laser light from the top surface of the first compound semiconductor layer through the first light reflection layer.

[0044] A partial end view of the pattern is shown in FIG. 1A, and a partial end view of the first light reflection layer and its vicinity is shown in FIGS. 1B, 2A, and 2B. As shown, the light-emitting element of Example 1 is formed by laminating a first light reflection layer 41, a laminated structure 20, and a second light reflection layer 42. The laminated structure 20 is formed by laminating a first compound semiconductor layer 21, a light-emitting layer (active layer) 23, and a second compound semiconductor layer 22 from the side of the first light reflection layer 41. Further, the light from the laminated structure 20 is emitted to the outside through the first light reflection layer 41 or the second light reflection layer 42 (in Example 1, through the second light reflection layer 42). The first light reflection layer 41 has a structure in which at least two types of thin films are laminated alternately, and a film thickness modulation layer 80 is provided between the laminated structure 20 and the first light reflection layer 41.

[0045] More specifically, the light-emitting element of Example 1 or the light-emitting elements of Examples 2 to 18 described later (A) A first compound semiconductor layer 21 having a first surface 21a and a second surface 21b facing the first surface 21a, and having a thickness of 4 nm and a first conductivity type (specifically, n-type), A light-emitting layer (active layer) 23 facing the second surface 21b of the first compound semiconductor layer 21, and A second compound semiconductor layer 22 having a first surface 22a facing the light-emitting layer 23 and a second surface 22b facing the first surface 22a, and having a thickness of 100 nm and a second conductivity type (specifically, p-type), Are laminated, a laminated structure 20 made of a GaN-based compound semiconductor, (B) A first light reflection layer 41 disposed on the first surface 21a side of the first compound semiconductor layer 21, and (C) A second light reflection layer 42 disposed on the second surface 22b side of the second compound semiconductor layer 22, Are provided. The thickness of the first compound semiconductor layer 21 is greater than the thickness of the second compound semiconductor layer 22.

[0046] Then, a resonator is formed by the region of the first light reflection layer 41 from the first surface 21a of the first compound semiconductor layer 21 to a certain depth, the stacked structure 20 (the first compound semiconductor layer 21, the light emitting layer 23, and the second compound semiconductor layer 22), and the region of the second light reflection layer 42 from the second surface 22b of the second compound semiconductor layer 22 to a certain depth.

[0047] In the following description, for convenience, the axis passing through the center of the resonator formed by the two light reflection layers may be referred to as the Z-axis, and the virtual plane orthogonal to the Z-axis may be referred to as the XY plane.

[0048] The first surface 11a of the substrate 11 for manufacturing a light emitting element made of a compound semiconductor substrate such as a conductive GaN substrate has, for example, the {0001} surface as the main surface. The first compound semiconductor layer 21 formed on the second surface 11b of the substrate 11 for manufacturing a light emitting element is composed of an n-GaN layer, and the light emitting layer (active layer) 23 is In 0.04 Ga 0.96 N layer (barrier layer) and In 0.16 Ga 0.84It is composed of a five - layer multiple quantum well structure in which N - layer (well layer) is laminated, and the second compound semiconductor layer 22 is composed of a p - GaN layer. The first electrode 31 is formed on the first surface 11a of the substrate 11 for manufacturing a light - emitting element. On the other hand, the second electrode 32 is formed on the second compound semiconductor layer 22, and the second light - reflecting layer 42 is formed on the second electrode 32. The first light - reflecting layer 41 and the second light - reflecting layer 42 on the second electrode 32 have a flat shape. The first electrode 31 is composed of Ti / Pt / Au, and the second electrode 32 is composed of a transparent conductive material, specifically, ITO. On the edge of the first electrode 31, a pad electrode (not shown), for example, composed of Ti / Pd / Au, is formed or connected for electrical connection to an external electrode or circuit. On the edge of the second electrode 32, a pad electrode 33, for example, composed of Pd / Ti / Pt / Au, Ti / Pd / Au, or Ti / Ni / Au, is formed or connected for electrical connection to an external electrode or circuit. The planar shapes (planar shapes when orthographically projected onto the XY plane) of the first electrode 31, the first light - reflecting layer 41, the second light - reflecting layer 42, and the opening 34A provided in the insulating layer (current constriction layer) 34 are circular. The second light - reflecting layer 42 is composed of a laminated structure of an SiN layer and an SiO 2 layer (total number of dielectric film laminations: 20 layers). Although the first light - reflecting layer 41 and the second light - reflecting layer 42 have such a multilayer structure, they are represented by one layer for simplification of the drawing.

[0049] In the light - emitting element of Example 1, the first light - reflecting layer 41 has a first thin film 41A with an optical film thickness t 1 and a second thin film 41B with an optical film thickness t 2 (however, t 2 ≠t 1 ), and a plurality of them are alternately laminated. Also, the film - thickness modulation layer 80 is composed of at least one third thin film with an optical film thickness t 3 (however, t 3 ≠t 1 ). Here, the first thin film 41A is made of a first material, and the second thin film 41B is made of a second material different from the first material. Specifically, the first material is SiN, and the second material is SiO 2That is, the first material is made of a dielectric material, and the second material is also made of a dielectric material. Thus, the material constituting the film thickness modulation layer may be different from the materials constituting the first compound semiconductor layer 21, the light emitting layer 23, and the second compound semiconductor layer 22. And as the degree of film thickness modulation, t 3 / t 1 ≧1.1, or t 3 / t 1 ≦0.9 is satisfied. For example, the number of layers of the first thin film 41A is 14, and the number of layers of the second thin film 41B is 14.

[0050] In some cases, the film thickness modulation layer 80 has a structure in which a third thin film 81 and a fourth thin film 82 having an optical film thickness t 4 are laminated. Furthermore, the film thickness modulation layer 80 has a structure in which a plurality of the third thin films 81 and the fourth thin films 82 are alternately laminated, and among the third thin films 81, the optical film thickness of at least one layer is t 3 ≠t 1 is satisfied. Furthermore, in some cases, among the fourth thin films 82, the optical film thickness of at least one layer is t 4 ≠t 2 is satisfied. Note that the third thin film that satisfies t 3 ≠t 1 is represented by reference numeral 81A, and for convenience, is referred to as 'the 3A thin film 81A', and the other third thin films are represented by reference numeral 81B, and for convenience, are referred to as 'the 3B thin film 81B'. Also, the fourth thin film that satisfies t 4 ≠t 2 is represented by reference numeral 82A, and for convenience, is referred to as 'the 4A thin film 82A', and the other fourth thin films are represented by reference numeral 82B, and for convenience, are referred to as 'the 4B thin film 82B'. Furthermore, the 3A thin film 81A that satisfies t 3 ≠t 1 , or the 4A thin film 82A that satisfies t 4 ≠t 2 is in contact with the first light reflection layer 41. Also, the 3B thin film 81B other than the 3A thin film 81A that satisfies t 3 ≠t 1 satisfies t 3 =t 1 , and t 4 ≠t 2The fourth thin film 82B other than the fourth thin film 82A that satisfies is t 4 =t 2 satisfies. The total number of layers of the third thin film 81 and the fourth thin film 82 is 5 or less. The third thin film 81 is made of the first material, and the fourth thin film 82 is made of the second material. Specifically, in Example 1, the film thickness and the like of each thin film are, for example, as shown in Table 1 below, but are not limited to these values. λ 0 = 435 nm.

[0051] 〈Table 1〉 Physical thickness Refractive index Optical film thickness The first thin film 41A 54.4 nm 2.00 t 1 = 109 nm The second thin film 41B 77.7 nm 1.40 t 2 = 109 nm The third thin film 81A 40.8 nm 2.00 t 3 = 81.6 nm The third thin film 81B 77.7 nm 1.40 t 1 = 109 nm The fourth thin film 82A 43.5 nm 2.00 t 4 = 87.0 nm The fourth thin film 82B 77.7 nm 1.40 t 2 = 109 nm

[0052] Here, in the example shown in FIG. 1B, the film thickness modulation layer 80 is composed of a single layer of the third thin film 81A. Further, in the example shown in FIG. 2A, the film thickness modulation layer 80 is composed of three layers, namely, the third thin film 81B, the fourth thin film 82B, and the third thin film 81A, from the side of the first compound semiconductor layer 21. Furthermore, in the example shown in FIG. 2B, the film thickness modulation layer 80 is composed of four layers, namely, the third thin film 81A, the fourth thin film 82B, the third thin film 81B, and the fourth thin film 82A, from the side of the first compound semiconductor layer 21. However, the configurations of these film thickness modulation layers 80 are merely examples and can be changed as appropriate. Tables 2, 3, and 4 below show the configurations of various film thickness modulation layers 80. In these tables, "3A" means the third thin film 81A, "3B" means the third thin film 81B, "4A" means the fourth thin film 82A, "4B" means the fourth thin film 82B, "1" in the column of "first light reflection layer" means the first thin film 41A, and "2" means the second thin film 41B.

[0053] 〈Table 2〉 JPEG0007683763000001.jpg13189

[0054] 〈Table 3〉 JPEG0007683763000002.jpg8389

[0055] 〈Table 4〉 JPEG0007683763000003.jpg6589

[0056] Furthermore, in the light-emitting element of Example 1, the first light reflection layer 41 is formed on a substrate (substrate 11 for manufacturing the light-emitting element), and the laminated structure 20 is formed on the region of the substrate (substrate 11 for manufacturing the light-emitting element) where the first light reflection layer 41 is not formed.

[0057] Hereinafter, with reference to FIGS. 3A, 3B, and 3C, which are schematic partial end views of the laminated structure and the like, the manufacturing method of the light-emitting element of Example 1 will be described.

[0058] [Process - 100] First, a first light reflection layer 41 is formed on the second surface 11b of the substrate 11 for manufacturing a light-emitting element based on a well-known method such as a sputtering method or a vacuum evaporation method. Further, a film thickness modulation layer 80 is formed based on a well-known method such as a sputtering method, a vacuum evaporation method, or a plasma CVD method. Then, based on a patterning method such as a wet etching method or a dry etching method, unnecessary portions of the film thickness modulation layer 80 and the first light reflection layer 41 are removed to obtain the first light reflection layer 41 and the film thickness modulation layer 80 having a desired shape (see FIG. 3A). The first light reflection layer 41 and the film thickness modulation layer 80 have a flat shape.

[0059] [Process - 110] Next, on the second surface 11b of the substrate 11 for manufacturing a light-emitting element including the film thickness modulation layer 80, a stacked structure 20 is formed based on lateral growth using a method of epitaxial growth in the lateral direction such as the ELO method. Specifically, a first compound semiconductor layer 21 having a first surface 21a and a second surface 21b facing the first surface 21a, a light-emitting layer (active layer) 23 facing the second surface 21b of the first compound semiconductor layer 21, and a second compound semiconductor layer 22 having a first surface 22a facing the light-emitting layer 23 and a second surface 22b facing the first surface 22a, are stacked to form a stacked structure 20 made of a GaN-based compound semiconductor.

[0060] [Process - 120] Next, on the second surface 22b of the second compound semiconductor layer 22, an insulating layer (current constriction layer) 34 made of SiO having an opening 34A is formed based on a combination of a film formation method such as a CVD method, a sputtering method, or a vacuum evaporation method and a wet etching method or a dry etching method (see FIG. 3B). The insulating layer 34 having the opening 34A defines a current constriction region (element region 61A and current non-injection region 61B). That is, the element region 61A is defined by the opening 34A. 2

[0061] [Process - 130] Thereafter, a second electrode 32 and a second light reflection layer 42 are formed on the second compound semiconductor layer 22. Specifically, starting from the second surface 22b of the second compound semiconductor layer 22 exposed at the bottom of the opening 34A (element region 61A), covering the insulating layer 34, for example, the second electrode 32 is formed based on the lift-off method. Further, a pad electrode 33 is formed based on a combination of a film formation method such as sputtering or vacuum evaporation and a patterning method such as wet etching or dry etching (see FIG. 3C). Next, covering from above the second electrode 32 to above the pad electrode 33, a second light reflection layer 42 is formed based on a combination of a film formation method such as sputtering or vacuum evaporation and a patterning method such as wet etching or dry etching. The second light reflection layer 42 above the second electrode 32 has a flat shape.

[0062] [Process - 140] Thereafter, by forming a first electrode 31 on the first surface 11a of the substrate 11 for manufacturing a light-emitting element based on a combination of a film formation method such as sputtering or vacuum evaporation and a patterning method such as wet etching or dry etching, a first electrode 31 electrically connected to the first compound semiconductor layer 21 can be obtained. Thus, the structure shown in FIG. 1A can be obtained.

[0063] [Process - 150] Thereafter, by performing so-called element isolation to separate the light-emitting element, the side surface and exposed surface of the laminated structure are covered with an insulating film made of, for example, SiO 2 And by packaging or encapsulating, the light-emitting element of Example 1 can be completed.

[0064] The results of simulating the optical field of the light-emitting device of Example 1 are shown in FIGS. 4A, 5A, and 5B. A light-emitting device without the film thickness modulation layer 80 is used as the light-emitting device of Comparative Example 1, and the result of simulating the optical field of the light-emitting device of Comparative Example 1 is shown in FIG. 4B. In FIGS. 4A, 4B, 5A, and 5B, the horizontal axis indicates the position of the first compound semiconductor layer 21, the position of the irregular structure (e.g., fine unevenness, point defects, line defects, voids, etc.), the position of the film thickness modulation layer 80, and the position of the first light reflection layer 41, the vertical axis indicates the intensity of the optical field, the rectangular line represents the refractive index, and the wavy line represents the intensity of the optical field. It is assumed that the film thickness modulation layer 80 is composed of a single thin film 81A of Group 3A. In the example shown in FIG. 5A, t 3 = 0.73λ 0 and in the example shown in FIG. 5B, t 3 = 1.23λ 0 . Also, in FIGS. 4B, 5A, and 5B, in the first light reflection layer 41, the film thickness t 1 of the first thin film 41A is set to 0.25λ 0 and the film thickness t 2 of the second thin film 41B is set to 0.25λ 0 . λ 0 is the wavelength (oscillation wavelength, emission wavelength) of the light mainly emitted from the light-emitting device.

[0065] In a surface-emitting laser device, the optical field repeats strong and weak regions in the resonator. As shown in Comparative Example 1 of FIG. 4B, when the film thickness modulation layer 80 is not formed, a strong region is generated in the optical field at the interface between the first light reflection layer 41 and the laminate structure 20, and optical loss occurs due to the irregular structure existing near the strong region of the optical field. However, as shown in FIGS. 4A, 5A, and 5B, in the light-emitting device of Example 1 in which the film thickness modulation layer 80 is formed, a strong region of the optical field is not formed at or near the interface between the laminate structure 20 and the film thickness modulation layer 80. Therefore, even if there is an irregular structure at or near the interface between the laminate structure 20 and the film thickness modulation layer 80, it is difficult for optical loss to occur, and it is possible to reliably avoid problems such as an increase in the threshold value of the light-emitting device, a decrease in the light-emitting efficiency, and a decrease in the quality of the emitted light.

[0066] In Comparative Example 1, in the same process as [Process - 110] of Example 1, when forming the laminated structure 20 based on lateral growth on the second surface 11b of the light - emitting element manufacturing substrate 11 including the first light - reflecting layer 41 using a method of epitaxial growth in the lateral direction such as the ELO method, irregular structures are likely to occur in the region of the laminated structure 20 formed on the first light - reflecting layer 41 (specifically, the first compound semiconductor layer 21 in contact with the first light - reflecting layer 41). As a result of such irregular structures absorbing or scattering light, optical losses occur. As fine irregularities, the root - mean - square roughness Rq≥1 nm can be cited. As the density of point defects, 1×10 17 / cm 3 or more can be exemplified. As the density of line defects, 1×10 6 / cm 3 or more can be exemplified. Also, voids exist at the interface between the laminated structure and the film - thickness modulation layer, and the thickness of the voids (the separation distance between the laminated structure and the film - thickness modulation layer) can be exemplified as 10 nm or less. That is, regarding irregular structures, unevenness is formed at the interface between the laminated structure and the film - thickness modulation layer, and the root - mean - square surface roughness Rq of the unevenness may be Rq≥1 nm, or alternatively, point defects are formed at the interface between the laminated structure and the film - thickness modulation layer, and the density of point defects may be 1×10 17 / cm 3 or more, or alternatively, the density of line defects may be 1×10 6 / cm 3 or more, or alternatively, voids are formed at the interface between the laminated structure and the film - thickness modulation layer, and the thickness of the voids may be 10 nm or less.

[0067] On the other hand, in the light - emitting element of Example 1, even if irregular structures occur at the interface between the laminated structure 20 and the film - thickness modulation layer 80 or in the vicinity thereof, since the film - thickness modulation layer 80 is formed, a region (antinode) with a strong optical field is not formed at the interface between the laminated structure 20 and the film - thickness modulation layer 80 or in the vicinity thereof. Therefore, problems such as an increase in the threshold value of the light - emitting element, a decrease in luminous efficiency, and a deterioration in the quality of the emitted light can be surely avoided.

Example

[0068] Example 2 is a modification of Example 1. More specifically, the light-emitting element of Example 2 is a surface-emitting laser element (vertical cavity laser, VCSEL) that emits laser light from the top surface of the first compound semiconductor layer 21 through the first light reflection layer 41.

[0069] In the light-emitting element of Example 2, as shown in a schematic partial cross-sectional view in FIG. 6A, the second light reflection layer 42 is fixed to a support substrate 49 made of a silicon semiconductor substrate by a soldering method via a bonding layer 48 composed of a gold (Au) layer or a solder layer containing tin (Sn). Further, the first light reflection layer 41 is formed on the exposed surface of the laminated structure 20.

[0070] Hereinafter, a method for manufacturing the light-emitting element of Example 2 will be described.

[0071] [Process - 200] First, for example, by performing the same processes as [Process - 100] to [Process - 130] of Example 1, the state shown in FIG. 1 (however, the first electrode 31 is not formed) can be obtained.

[0072] [Process - 210] Thereafter, the second light reflection layer 42 is fixed to the support substrate 49 via the bonding layer 48.

[0073] [Process - 220] Next, the substrate 11 for manufacturing the light-emitting element is removed to expose the first surface 21a of the first compound semiconductor layer 21 and the first light reflection layer 41. Specifically, first, based on the mechanical polishing method, the thickness of the substrate 11 for manufacturing the light-emitting element is reduced, and then, based on the CMP method, the remaining portion of the substrate 11 for manufacturing the light-emitting element is removed. Thus, the first surface 21a of the first compound semiconductor layer 21 and the first light reflection layer 41 are exposed.

[0074] [Process - 230] Thereafter, the first electrode 31 is formed on the first surface 21a of the first compound semiconductor layer 21. Thus, the light-emitting element of Example 2 having the structure shown in FIG. 6A can be obtained.

[0075] In the manufacture of the light-emitting element of Example 2, the substrate for manufacturing the light-emitting element is removed in a state where the first light reflection layer is formed. Therefore, as a result of the first light reflection layer functioning as a kind of stopper (stopper layer) when removing the substrate for manufacturing the light-emitting element, variations in the amount of removal of the substrate for manufacturing the light-emitting element within the plane of the substrate for manufacturing the light-emitting element, and further, variations in the thickness of the first compound semiconductor layer can be suppressed, and as a result, the length of the resonator can be made uniform, and stabilization of the characteristics of the obtained light-emitting element can be achieved. Moreover, since the surface (flat surface) of the first compound semiconductor layer at the interface between the first light reflection layer and the first compound semiconductor layer is flat, scattering of laser light on the flat surface can be minimized.

[0076] As described above, in the example of the light-emitting element shown in Fig. 6A, the end of the first electrode 31 is separated from the first light reflection layer 41. That is, the first light reflection layer 41 and the first electrode 31 are separated, in other words, they have an offset, and the separation distance is within 1 mm, specifically, for example, an average of 0.05 mm. However, it is not limited to such a structure, and the end of the first electrode 31 may be in contact with the first light reflection layer 41, or the end of the first electrode 31 may be formed across the edge of the first light reflection layer 41.

[0077] Alternatively, as shown in Fig. 6B which is a schematic partial end view, in the light-emitting element of Example 2, the first light reflection layer 41 may be formed on the exposed surface of the laminated structure 20. That is, by omitting [Process - 100] of Example 1, first, for example, after performing the same processes as [Process - 110] to [Process - 130] of Example 1, [Process - 210] and [Process - 220] are performed to expose the first surface 21a of the first compound semiconductor layer 21, and then, a film thickness modulation layer 80, a first light reflection layer 41, and a first electrode 31 may be formed on the first surface 21a of the first compound semiconductor layer 21. For example, specifically, the first material is SiO 2 and the second material is Ta 2 O 5 is used. The film thicknesses of the respective thin films are as shown in Table 5 below, but are not limited to these values. λ 0=488 nm. The number of layers in first thin film 41A is seven, and the number of layers in second thin film 41B is seven.

[0078] Physical thickness Refractive index Optical thickness First thin film 41A 87.1nm 1.40t 1 =122nm Second thin film 41B 55.5nm 2.20t 2 =122nm 3A thin film 81A 65.4nm 1.40t 3 = 91.6 nm 3B thin film 81B 55.5nm 2.20t 1 =122nm 4th A thin film 82A 69.7nm 1.40t 4 = 97.6 nm 4th B thin film 82B 55.5nm 2.20t 2 =122nm

[0079] In such a modified example of the light-emitting element of Example 2, when the remaining part of the light-emitting element manufacturing substrate 11 is removed based on the CMP method in [Step-220] to expose the first surface 21a of the first compound semiconductor layer 21, even if an irregular structure occurs near the surface of the exposed part, since the film thickness modulation layer 80 is formed, a region of strong optical field is not formed at the interface of the first light reflecting layer 41 in contact with the film thickness modulation layer 80 and in the region nearby, and therefore optical loss can be suppressed.

[0080] Furthermore, when forming the first light reflecting layer 41 on the first surface 21a of the first compound semiconductor layer 21, the first compound semiconductor layer 21 may be etched to form a recess in the first surface 21a of the first compound semiconductor layer 21, and the first light reflecting layer 41 may be formed in this recess (see FIG. 7A). The inclined portion formed in the first compound semiconductor layer 21 is indicated by reference number 41a. EXAMPLES

[0081] Example 3 is also a modification of Example 1. As shown in the schematic partial end view of FIG. 7B, in the light-emitting element of Example 3, the first material constituting the first thin film and the third thin film is a compound semiconductor material, specifically, made of AlInN, and the second material constituting the second thin film and the fourth thin film is also a compound semiconductor material, specifically, can be in the form of being made of GaN. And, similar to Example 1, as the film thickness modulation degree, t 3 / t 1 ≧1.1, or t 3 / t 1 ≦0.9 is satisfied. Specifically, in Example 3, the film thicknesses of the respective thin films, etc. are as shown in Table 6 below, but are not limited to these values. λ 0 =515 nm. Also, the number of layers of the first thin film is 40, and the number of layers of the second thin film is 40.

[0082] 〈Table 6〉 Physical thickness Refractive index Optical film thickness First thin film 41A 49.3 nm 2.61 t 1 =129 nm Second thin film 41B 52.8 nm 2.44 t 2 =129 nm First thin film of the third layer 81A 56.7 nm 2.61 t 3 =148 nm Second thin film of the third layer 81B 52.8 nm 2.44 t 1 =129 nm First thin film of the fourth layer 82A 56.7 nm 2.61 t 4 =148 nm Second thin film of the fourth layer 82B 52.8 nm 2.44 t 2 =129 nm

[0083] The light-emitting element of Example 3 may be formed by epitaxially growing a first light reflection layer 41 and a film thickness modulation layer 80 each composed of a multilayer film of a first thin film 41A and a second thin film 41B on the second surface 11b of a substrate 11 for manufacturing a light-emitting element made of a GaN substrate having, for example, a {20-21} plane as a main plane in the same process as [Process-100] of Example 1. Thereafter, the same processes as [Process-110] to [Process-150] of Example 1 may be executed. In Example 3, in principle, patterning of the first light reflection layer 41 and the film thickness modulation layer 80 is unnecessary. Thus, finally, a light-emitting element having the structure shown in FIG. 7B can be obtained.

Example

[0084] Example 4 is a modification of Examples 1 to 3. In the light-emitting element of Example 4, at least two light absorption material layers are formed parallel to a virtual plane occupied by the light-emitting layer inside the stacked structure (or in the stacked structure including the second electrode). For convenience, the light-emitting elements of such Example 4 or Examples 5 to 6 described later are referred to as 'light-emitting elements provided with light absorption material layers'.

[0085] As described above, a stacked structure 20 is formed between the two DBR layers 41 and 42. The resonator length L inside the light-emitting stacked body composed of the two DBR layers 41 and 42 and the stacked structure 20 formed therebetween OR is the equivalent refractive index of the entire light-emitting stacked body as n eq , the wavelength of the laser light to be emitted from the surface-emitting laser element (light-emitting element) as λ 0 , and when L OR =(m·λ 0 ) / (2·n eq ) (A) is represented. Here, m is a positive integer. By the way, in the surface-emitting laser element (light-emitting element), the oscillatable wavelength is determined by the resonator length L OR . Each oscillatable oscillation mode is called a longitudinal mode. Among the longitudinal modes, the one that matches the gain spectrum determined by the light-emitting layer can laser oscillate. The interval Δλ between the longitudinal modes is the effective refractive index as neff When it is set to λ 0 2 / (2n eff ·L OR ) is represented by. That is, the longer the resonator length L OR is, the narrower the interval Δλ between the longitudinal modes becomes. Therefore, when the resonator length L OR is long, since a plurality of longitudinal modes can exist within the gain spectrum, a plurality of longitudinal modes can oscillate. Note that between the equivalent refractive index n eq and the effective refractive index n eff when the oscillation wavelength is λ 0 the following relationship exists.

[0086] n eff = n eq - λ 0 ·(dn eq / dλ 0 )

[0087] Here, when the resonator length L OR is as short as 1 μm or less, the laser light of the longitudinal mode emitted from the surface-emitting laser element is usually of one type (one wavelength) (see the conceptual diagram in Fig. 12A). Therefore, it is possible to accurately control the oscillation wavelength of the laser light emitted from the surface-emitting laser element.

[0088] On the other hand, when the resonator length L OR is several times or more longer than the wavelength of the laser light emitted from the surface-emitting laser element, the laser light of the longitudinal mode that can be emitted from the surface-emitting laser element becomes of a plurality of types (see the conceptual diagram in Fig. 12B), and it may become difficult to accurately control the oscillation wavelength of the laser light emitted from the surface-emitting laser element.

[0089] Specifically, when the stacked structure is composed of a GaAs-based compound semiconductor layer, the resonator length L ORis usually as short as 1 μm or less, and the laser light in the longitudinal mode emitted from the surface-emitting laser element is of one type (one wavelength). Therefore, it is possible to accurately control the oscillation wavelength of the laser light in the longitudinal mode emitted from the surface-emitting laser element. On the other hand, when the stacked structure is composed of GaN-based compound semiconductor layers, the resonator length L OR is usually several times longer than the wavelength of the laser light emitted from the surface-emitting laser element. Therefore, there may be a case where multiple types of laser light in the longitudinal mode can be emitted from the surface-emitting laser element, and it may be difficult to accurately control the oscillation wavelength of the laser light that can be emitted from the surface-emitting laser element.

[0090] In the light-emitting element including the light absorption material layer in the present disclosure, it is possible to accurately control the oscillation wavelength of such emitted laser light. That is, in the light-emitting element including the light absorption material layer, since at least two light absorption material layers are formed inside the stacked structure, among the multiple types of laser light in the longitudinal mode that can be emitted from the surface-emitting laser element, the oscillation of the laser light in the undesired longitudinal mode can be suppressed. As a result, it is possible to accurately control the oscillation wavelength of the emitted laser light.

[0091] In such a light-emitting element including the light absorption material layer, it is preferable that at least four light absorption material layers are formed.

[0092] In the light-emitting element including the light absorption material layer including the above preferable form, when the oscillation wavelength (the desired oscillation wavelength emitted from the light-emitting element) is λ 0 , the equivalent refractive index of the entire part of the stacked structure located between the two light absorption material layers and between the light absorption material layers is n eq , and the distance between the light absorption material layers is L Abs , then 0.9×{(m·λ 0 ) / (2·n eq )}≦L Abs ≦1.1×{(m·λ 0 ) / (2·n eq )} (B-1) It is preferable to satisfy this. Here, m is 1 or any integer of 2 or more including 1. The equivalent refractive index n eq refers to the respective thicknesses t of the two light absorption material layers and each layer constituting the part of the laminated structure located between the light absorption material layers i , and the respective refractive indices n i . When n eq =Σ(t i ×n i ) / Σ(t i ) is represented by. However, i = 1, 2, 3 ···, I, where "I" is the total number of layers constituting the two light absorption material layers and the part of the laminated structure located between the light absorption material layers, and "Σ" means taking the sum from i = 1 to i = I. The equivalent refractive index n eq can be calculated based on observing the constituent materials from an electron microscope observation of the cross-section of the light-emitting element, etc., and using the known refractive indices and the thicknesses obtained by observation for each constituent material. When m = 1, the distance between adjacent light absorption material layers is, in all of the plurality of light absorption material layers 0.9×{λ 0 / (2·n eq )}≦L Abs ≦1.1×{λ 0 / (2·n eq )} (B - 2) is satisfied. Also, when m is any integer of 2 or more including 1, for example, if m = 1, 2, in some of the light absorption material layers, the distance between adjacent light absorption material layers is 0.9×{λ 0 / (2·n eq )}≦L Abs ≦1.1×{λ 0 / (2·n eq )} (B - 2) is satisfied, and in the remaining light absorption material layers, the distance between adjacent light absorption material layers is 0.9×{(2·λ 0 ) / (2·n eq )}≦L Abs ≦1.1×{(2·λ 0 ) / (2·n eq )} (B - 3) is satisfied. Broadly, in some light absorption material layers, the distance between adjacent light absorption material layers is 0.9×{λ 0 / (2·n eq )}≦L Abs ≦1.1×{λ 0 / (2·n eq )} (B-2) is satisfied, and in the remaining various light absorption material layers, the distance between adjacent light absorption material layers is 0.9×{(m’·λ 0 ) / (2·n eq )}≦L Abs ≦1.1×{(m’·λ 0 ) / (2·n eq )} (B-4) is satisfied. Here, m’ is an arbitrary integer of 2 or more. Also, the distance between adjacent light absorption material layers is the distance between the centers of gravity of adjacent light absorption material layers. That is, actually, it is the distance between the centers of each light absorption material layer when cut by a virtual plane along the thickness direction of the light emitting layer.

[0093] Furthermore, in a light emitting device including a light absorption material layer including the above various preferred forms, the thickness of the light absorption material layer is preferably λ 0 / (4·n eq ) or less. 1 nm can be exemplified as the lower limit value of the thickness of the light absorption material layer.

[0094] Furthermore, in a light emitting device including a light absorption material layer including the above various preferred forms, the light absorption material layer can be positioned at the lowest amplitude portion generated in the standing wave of light formed inside the laminate structure.

[0095] Furthermore, in a light emitting device including a light absorption material layer including the above various preferred forms, the light emitting layer can be positioned at the maximum amplitude portion generated in the standing wave of light formed inside the laminate structure.

[0096] Furthermore, in a light-emitting device including a light absorption material layer including the above-described various preferred forms, the light absorption material layer can be configured to have a light absorption coefficient that is at least twice the light absorption coefficient of the compound semiconductor constituting the stacked structure. Here, the light absorption coefficient of the light absorption material layer and the light absorption coefficient of the compound semiconductor constituting the stacked structure can be determined by observing the constituent materials from an electron microscope observation or the like of the cross-section of the light-emitting device and extrapolating from the known evaluation results observed for each constituent material.

[0097] Furthermore, in a light-emitting device including a light absorption material layer including the above-described various preferred forms, the light absorption material layer can be configured to be composed of at least one material selected from the group consisting of a compound semiconductor material having a smaller bandgap than the compound semiconductor constituting the stacked structure, a compound semiconductor material doped with impurities, a transparent conductive material, and a light reflection layer constituent material having light absorption characteristics. Here, as the compound semiconductor material having a smaller bandgap than the compound semiconductor constituting the stacked structure, for example, when the compound semiconductor constituting the stacked structure is GaN, InGaN can be mentioned. As the compound semiconductor material doped with impurities, n-GaN doped with Si and n-GaN doped with B can be mentioned. As the transparent conductive material, the transparent conductive material constituting the electrode described above can be mentioned. As the light reflection layer constituent material having light absorption characteristics, the material constituting the light reflection layer described above (for example, SiO X , SiN X , TaO XExamples include (etc.). All of the light absorption material layers may be composed of one type of these materials. Alternatively, each of the light absorption material layers may be composed of various materials selected from these materials, but it is preferable from the viewpoint of simplifying the formation of the light absorption material layer that one light absorption material layer is composed of one type of material. The light absorption material layer may be formed within the first compound semiconductor layer, within the second compound semiconductor layer, within the first light reflection layer, within the second light reflection layer, or any combination thereof. Alternatively, the light absorption material layer can also be used as an electrode made of the above-described transparent conductive material.

[0098] As shown in a schematic partial cross-sectional view in FIG. 8A, in the light-emitting element of Example 4 or the light-emitting elements of Examples 5 to 6 described later, in the laminated structure 20 including the second electrode 32, at least two light absorption material layers 91 are formed in parallel with the virtual plane occupied by the light-emitting layer 23. Preferably, at least four light absorption material layers 91 are formed. Specifically, in Example 4, 20 light absorption material layers 91 are formed. Note that, for simplicity of the drawing, only two light absorption material layers 91 are shown in the drawing.

[0099] Oscillation wavelength (desired oscillation wavelength emitted from the light-emitting element) λ 0 is 450 nm. The 20 light absorption material layers 91 are made of a compound semiconductor material having a narrower bandgap than the compound semiconductor constituting the laminated structure 20. Specifically, n-In 0.2 Ga 0.8 N and are formed inside the first compound semiconductor layer 21. The thickness of the light absorption material layer 91 is λ 0 / (4·n eq ) or less, specifically 3 nm. The light absorption coefficient of the light absorption material layer 91 is at least twice the light absorption coefficient of the first compound semiconductor layer 21 made of an n-GaN layer. Specifically, it is 1×10 3 times.

[0100] Further, the light absorption material layer 91 is located at the lowest amplitude portion generated in the standing wave of light formed inside the laminated structure, and the light emitting layer 23 is located at the maximum amplitude portion generated in the standing wave of light formed inside the laminated structure. The distance between the center in the thickness direction of the light emitting layer 23 and the center in the thickness direction of the light absorption material layer 91 adjacent to the light emitting layer 23 is 46.5 nm. Furthermore, the overall equivalent refractive index of the two light absorption material layers 91 and the portion of the laminated structure located between the light absorption material layer 91 and the light absorption material layer 91 (specifically, in Example 4, the first compound semiconductor layer 21) is n eq , the distance between the light absorption material layer 91 and the light absorption material layer 91 is L Abs When it is set as 0.9×{(m·λ 0 ) / (2·n eq )}≦L Abs ≦1.1×{(m·λ 0 ) / (2·n eq )} (B-1) is satisfied. Here, m is 1 or any integer of 2 or more including 1. However, in Example 4, m = 1. Therefore, the distance between adjacent light absorption material layers 91 is, in all of the plurality of light absorption material layers 91 (20 light absorption material layers 91), 0.9×{λ 0 / (2·n eq )}≦L Abs ≦1.1×{λ 0 / (2·n eq )} (B-2) is satisfied. The value of the equivalent refractive index n eq is specifically 2.42, and when m = 1, specifically, L Abs =1×450 / (2×2.42) =93.0nm That is. Among the 20 light absorption material layers 91, for some light absorption material layers 91, m can also be any integer of 2 or more.

[0101] The light emitting element of Example 4 can be obtained by forming 20 light absorption material layers 91 inside the first compound semiconductor layer 21 when forming the first compound semiconductor layer 21.

[0102] When a plurality of longitudinal modes are generated within the gain spectrum determined by the light-emitting layer 23, a schematic representation thereof is as shown in FIG. 11. In FIG. 11, two longitudinal modes, longitudinal mode A and longitudinal mode B, are illustrated. And in this case, it is assumed that the light absorption material layer 91 is located at the lowest amplitude portion of longitudinal mode A and not at the lowest amplitude portion of longitudinal mode B. Then, the mode loss of longitudinal mode A is minimized, but the mode loss of longitudinal mode B is large. In FIG. 11, the mode loss portion of longitudinal mode B is schematically shown by a solid line. Therefore, longitudinal mode A is more likely to oscillate than longitudinal mode B. Therefore, by using such a structure, that is, by controlling the position and period of the light absorption material layer 91, a specific longitudinal mode can be stabilized and made more likely to oscillate. On the other hand, since the mode loss for other unwanted longitudinal modes can be increased, it becomes possible to suppress the oscillation of other unwanted longitudinal modes.

[0103] As described above, in the light-emitting element of Example 4, since at least two light absorption material layers are formed inside the laminated structure, among the plurality of types of laser light of longitudinal modes that can be emitted from the surface-emitting laser element, the oscillation of the laser light of the unwanted longitudinal mode can be suppressed. As a result, it becomes possible to accurately control the oscillation wavelength of the emitted laser light.

[0104] Examples of applying the configuration and structure of the light-emitting element of Example 2 shown in FIG. 6A to the light-emitting element of Example 4 are shown in a schematic partial end face view of FIG. 8B, examples of applying the configuration and structure of the modified example of the light-emitting element of Example 2 shown in FIG. 6B to the light-emitting element of Example 4 are shown in a schematic partial end face view of FIG. 9A, examples of applying the configuration and structure of the modified example of the light-emitting element of Example 2 shown in FIG. 7A to the light-emitting element of Example 4 are shown in a schematic partial end face view of FIG. 9B, and examples of applying the configuration and structure of the light-emitting element of Example 3 shown in FIG. 7B to the light-emitting element of Example 4 are shown in a schematic partial end face view of FIG. 10.

Example

[0105] Example 5 is a modification of Example 4. In Example 4, the light absorption material layer 91 was composed of a compound semiconductor material having a narrower bandgap than the compound semiconductor constituting the laminate 20. On the other hand, in Example 5, ten light absorption material layers 91 were composed of a compound semiconductor material doped with impurities, specifically, a compound semiconductor material having an impurity concentration (impurity: Si) of 1×10 19 / cm 3 (specifically, n-GaN: Si). Further, in Example 5, the oscillation wavelength λ 0 was set to 515 nm. The composition of the light emitting layer 23 is In 0.3 Ga 0.7 N. In Example 5, m = 1, the value of L Abs was 107 nm, the distance between the center in the thickness direction of the light emitting layer 23 and the center in the thickness direction of the light absorption material layer 91 adjacent to the light emitting layer 23 was 53.5 nm, and the thickness of the light absorption material layer 91 was 3 nm. Except for the above points, the configuration and structure of the light emitting device of Example 5 can be the same as those of the light emitting device of Example 4, and thus detailed description is omitted. Note that, in some of the ten light absorption material layers 91, m can be any integer of 2 or more.

Example

[0106] Example 6 is also a modification of Example 4. In Example 6, five light absorption material layers (for convenience, referred to as "first light absorption material layers") were configured in the same manner as the light absorption material layer 91 of Example 4, that is, composed of n-In 0.3 Ga 0.7 N. Further, in Example 6, one light absorption material layer (for convenience, referred to as "second light absorption material layer") was composed of a transparent conductive material. Specifically, the second light absorption material layer was also used as the second electrode 32 made of ITO. In Example 6, the oscillation wavelength λ 0 was set to 450 nm. Also, m = 1 and 2. When m = 1, L AbsThe value of is 93.0 nm, the distance between the center in the thickness direction of the light-emitting layer 23 and the center in the thickness direction of the first light absorption material layer adjacent to the light-emitting layer 23 is 46.5 nm, and the thickness of the five-layer first light absorption material layer is 3 nm. That is, for the five-layer first light absorption material layer, 0 0.9×{λ eq / (2·n Abs )}≦L 0 / (2·n eq )} (B-2) is satisfied. Also, for the first light absorption material layer adjacent to the light-emitting layer 23 and the second light absorption material layer, m = 2. That is, 0.9×{(2·λ 0 ) / (2·n eq )}≦L Abs ≦1.1×{(2·λ 0 ) / (2·n eq )} (B-3) is satisfied. The light absorption coefficient of the single-layer second light absorption material layer also serving as the second electrode 32 is 2000 cm -1 , the thickness is 30 nm, and the distance from the light-emitting layer 23 to the second light absorption material layer is 139.5 nm. Except for the above points, the configuration and structure of the light-emitting element of Example 6 can be the same as those of the light-emitting element of Example 4, so detailed description is omitted. In addition, for some of the five-layer first light absorption material layers, m can be any integer of 2 or more. Note that, different from Example 4, the number of the light absorption material layers 91 can also be 1. Also in this case, the positional relationship between the second light absorption material layer also serving as the second electrode 32 and the light absorption material layer 91 needs to satisfy the following formula. 0.9×{(m·λ 0 ) / (2·n eq )}≦L Abs ≦1.1×{(m·λ 0 ) / (2·n eq )} (B-1)

Example

[0107] Example 7 is a modification of Examples 1 to 6. In the light-emitting element of Example 7 or Examples 8 to 18 described later, the first light reflection layer and the film thickness modulation layer (hereinafter, the first light reflection layer and the film thickness modulation layer are collectively referred to as, for convenience, the 'first light reflection layer etc.') have a concave mirror portion, and the second light reflection layer has a flat shape. Incidentally, the light-emitting element of Example 7 or Examples 8 to 18 described later is, for convenience, referred to as the 'light-emitting element having a concave mirror portion of the present disclosure'.

[0108] By the way, when the laminated structure is composed of a GaAs-based compound semiconductor, the resonator length L OR is about 1 μm. On the other hand, when the laminated structure is composed of a GaN-based compound semiconductor, the resonator length L OR is usually several times longer than the wavelength of the laser light emitted from the surface-emitting laser element. That is, the resonator length L OR is much longer than 1 μm. And when the resonator length L OR becomes long like this, different from the conventional GaAs-based surface-emitting laser element adopting a resonator length L OR of about 1 μm, there is a possibility that laser oscillation becomes difficult because the diffraction loss increases. That is, there is a possibility that it will not function as a surface-emitting laser element but will function as an LED. Here, the 'diffraction loss' generally refers to a phenomenon in which, because light tends to spread due to the diffraction effect, the laser light reciprocating in the resonator gradually dissipates outside the resonator. Further, when the laminated structure is composed of a GaN-based compound semiconductor, there is a problem of thermal saturation. Here, the 'thermal saturation' is a phenomenon in which the light output saturates due to self-heating when the surface-emitting laser element is driven. The materials used for the light reflection layer (for example, materials such as SiO 2 and Ta 2 O 5 ) have a lower thermal conductivity value than the GaN-based compound semiconductor. Therefore, increasing the thickness of the GaN-based compound semiconductor layer leads to suppressing thermal saturation. However, when the thickness of the GaN-based compound semiconductor layer is increased, the resonator length L ORSince the length becomes long, the above problem occurs. Techniques for imparting the function of a concave mirror to the light reflection layer are well known from, for example, Japanese Patent Application Laid-Open No. 2006-114753 and Japanese Patent Application Laid-Open No. 2000-022277. However, these patent publication gazettes do not mention anything about problems such as an increase in diffraction loss caused by an increase in the resonator length L OR or problems of thermal saturation.

[0109] In the light-emitting element having the concave mirror portion of the present disclosure, since the first light reflection layer or the like has the concave mirror portion, the light diffracts and spreads from the light-emitting layer as a starting point, and the light incident on the first light reflection layer is surely reflected toward the light-emitting layer and can be condensed on the light-emitting layer. Therefore, it is possible to avoid an increase in diffraction loss, and it is possible to surely perform laser oscillation. Also, since it has a long resonator, it is possible to avoid the problem of thermal saturation.

[0110] And in the light-emitting element having the concave mirror portion of the present disclosure as described above, when the resonator length is L OR it is preferable to satisfy 1×10 -5 m≦L OR .

[0111] In the light-emitting element having the concave mirror portion of the present disclosure including the above preferable form, when the first light reflection layer or the like is cut by a virtual plane including the stacking direction of the stacked structure, the interface (specifically, the interface between the film thickness modulation layer and the stacked structure) facing a part of the stacked structure of the concave mirror portion composed of the first light reflection layer or the like can be in a form that is a part of a circle or a part of a parabola. The figure may not be exactly a part of a circle in some cases, and may not be exactly a part of a parabola in some cases. That is, even when it is generally a part of a circle or generally a part of a parabola, it is included in "the figure is a part of a circle or a part of a parabola". Such a part (region) of the first light reflection layer or the like that is a part of a circle or a part of a parabola may be referred to as the 'effective region in the concave mirror portion of the first light reflection layer or the like'. Note that the figure drawn by the interface facing a part of the stacked structure of the concave mirror portion can be obtained by measuring the shape of the interface with a measuring instrument and analyzing the obtained data based on the least squares method.

[0112] In the light-emitting device having the concave mirror portion of the present disclosure including the above-described preferred embodiment, the second compound semiconductor layer is provided with a current injection region and a current non-injection region surrounding the current injection region. The shortest distance D from the area centroid point of the current injection region to the boundary between the current injection region and the current non-injection region CI can be configured to satisfy the following formula. Here, the light-emitting device having such a configuration is, for convenience, referred to as the 'light-emitting device of the first configuration'. Note that the derivation of the following formula can be found, for example, in H. Kogelnik and T. Li, "Laser Beams and Resonators", Applied Optics / Vol. 5, No. 10 / October 1966. Also, ω 0 is also called the beam waist radius.

[0113] D CI ≧ω 0 / 2 (C-1) However, ω 0 2 ≡(λ 0 / π){L OR (R DBR -L OR )} 1 / 2 (C-2) Here, λ 0 : The wavelength (oscillation wavelength) of the light mainly emitted from the light-emitting device L OR : Resonator length R DBR : The radius of curvature of the concave mirror portion composed of the first light reflection layer, etc.

[0114] Here, the light-emitting device having the concave mirror portion of the present disclosure has the concave mirror portion only in the first light reflection layer, etc. However, considering the symmetry with respect to the flat mirror of the second light reflection layer, the resonator can be extended to a Fabry-Perot type resonator sandwiched between two concave mirror portions having the same radius of curvature (see the schematic diagram in Fig. 37). At this time, the resonator length of the virtual Fabry-Perot type resonator is twice the resonator length L OR . ω 0The value and the resonator length L OR The value and the radius of curvature R of the concave mirror portion composed of the first light reflection layer and the like DBR Graphs showing the relationship between the values are shown in FIGS. 38 and 39. Incidentally, when the value of ω 0 is "negative", that is, when the value of the radius of curvature R DBR is smaller than the value of the resonator length L OR in a state where the confinement of the optical field becomes excessive and diffraction loss occurs. Therefore, it is preferable that the value of the radius of curvature R DBR is larger than the value of the resonator length L OR . Incidentally, when the light-emitting layer is arranged closer to the flat light reflection layer among the two light reflection layers, specifically, the second light reflection layer, the optical field is more condensed in the light-emitting layer. That is, the optical field confinement in the light-emitting layer is strengthened, facilitating laser oscillation. Although not limited, as the position of the light-emitting layer, that is, the distance from the surface of the second light reflection layer facing the second compound semiconductor layer to the light-emitting layer, λ 0 / 2 to 10λ 0 can be exemplified.

[0115] By the way, when the region where the light reflected by the first light reflection layer is condensed is not included in the current injection region corresponding to the region where the light-emitting layer has gain by current injection, the induced emission of light from the carriers is inhibited, and ultimately, there is a possibility that laser oscillation is inhibited. By satisfying the above formulas (C-1) and (C-2), it is possible to ensure that the region where the light reflected by the first light reflection layer is condensed is included in the current injection region, and laser oscillation can be surely achieved.

[0116] And the light-emitting element of the first configuration is provided on the second surface of the second compound semiconductor layer, and a mode loss action site that constitutes a mode loss action region that acts on the increase and decrease of the oscillation mode loss a second electrode formed across the mode loss action site from the second surface of the second compound semiconductor layer, and a first electrode electrically connected to the first compound semiconductor layer and further includes the second light reflection layer is formed on the second electrode The stacked structure is formed with a current injection region, a current non-injection / inner region surrounding the current injection region, and a current non-injection / outer region surrounding the current non-injection / inner region. The orthographic image of the mode loss action region and the orthographic image of the current non-injection / outer region can be configured to overlap.

[0117] And, in the light-emitting element of the first configuration including such a preferable configuration, the radius r’ of the effective region in the concave mirror portion composed of the first light reflection layer and the like DBR is ω 0 ≦r’ DBR ≦20·ω 0 , preferably, ω 0 ≦r’ DBR ≦10·ω 0 can satisfy the configuration. Alternatively, as the value of r’ DBR , r’ DBR ≦1×10 -4 m, preferably, r’ DBR ≦5×10 -5 m can be exemplified. Also, as the height h of the base DBR , h DBR ≦5×10 -5 m can be exemplified. Furthermore, in the light-emitting element of the first configuration including such a preferable configuration, D CI ≧ω 0 can satisfy the configuration. Furthermore, in the light-emitting element of the first configuration including such a preferable configuration, R DBR ≦1×10 -3 m, preferably, 1×10 -5 m≦R DBR ≦1×10 -3 m, more preferably, 1×10 -5 m≦R DBR ≦1×10 -4 m can satisfy the configuration.

[0118] Also, the light-emitting element having the concave mirror portion of the present disclosure including the above preferable form is provided on the second surface of the second compound semiconductor layer, and a mode loss action site that constitutes a mode loss action region that acts on the increase and decrease of the oscillation mode loss. A second electrode formed across the mode loss action site from the second surface of the second compound semiconductor layer, and A first electrode electrically connected to the first compound semiconductor layer, further comprising The second light reflection layer is formed on the second electrode, In the laminated structure, a current injection region, a current non-injection / inner region surrounding the current injection region, and a current non-injection / outer region surrounding the current non-injection / inner region are formed, The orthographic image of the mode loss action region and the orthographic image of the current non-injection / outer region can be configured to overlap. Here, for convenience, a light-emitting element having such a configuration is referred to as a 'light-emitting element of the second configuration'.

[0119] Alternatively, a light-emitting element having a concave mirror portion of the present disclosure including the above-described preferred form A second electrode formed on the second surface of the second compound semiconductor layer, A second light reflection layer formed on the second electrode, A mode loss action site provided on the first surface of the first compound semiconductor layer and constituting a mode loss action region that acts on the increase and decrease of the oscillation mode loss, and A first electrode electrically connected to the first compound semiconductor layer, further comprising The first light reflection layer or the like is formed across the mode loss action site from the first surface of the first compound semiconductor layer, In the laminated structure, a current injection region, a current non-injection / inner region surrounding the current injection region, and a current non-injection / outer region surrounding the current non-injection / inner region are formed, The orthographic image of the mode loss action region and the orthographic image of the current non-injection / outer region can be configured to overlap. Here, for convenience, a light-emitting element having such a configuration is referred to as a 'light-emitting element of the third configuration'. Note that the definition of the light-emitting element of the third configuration can be applied to the light-emitting element of the first configuration.

[0120] In the light-emitting element of the second configuration or the light-emitting element of the third configuration, a current non-injection region (a general term for a current non-injection inner region and a current non-injection outer region) is formed in the stacked structure. Specifically, the current non-injection region may be formed in a region on the second electrode side of the second compound semiconductor layer in the thickness direction, may be formed in the entire second compound semiconductor layer, may be formed in the second compound semiconductor layer and the light-emitting layer, or may be formed across a part of the first compound semiconductor layer from the second compound semiconductor layer. The orthographic image of the mode loss action region and the orthographic image of the current non-injection outer region overlap, but in a region sufficiently separated from the current injection region, the orthographic image of the mode loss action region and the orthographic image of the current non-injection outer region do not necessarily overlap.

[0121] In the light-emitting element of the second configuration, the current non-injection outer region can be configured to be located below the mode loss action region.

[0122] In the light-emitting element of the second configuration including the above preferable configuration, when the area of the orthographic image of the current injection region is S 1 and the area of the orthographic image of the current non-injection inner region is S 2 , 0.01 ≦ S 1 / (S 1 + S 2 ) ≦ 0.7 (D - 1) can be satisfied. Also, in the light-emitting element of the third configuration, when the area of the orthographic image of the current injection region is S 1 ’ and the area of the orthographic image of the current non-injection inner region is S 2 ’, 0.01 ≦ S 1 ’ / (S 1 ’ + S 2 ) ≦ 0.7 (D - 2) can be satisfied. However, the ranges of S 1 / (S 1 ’ + S 2 ) and S 1 ’ / (S 1 ’ + S 2 ’) are not limited or restricted to the above ranges.

[0123] In the light-emitting element of the second configuration or the light-emitting element of the third configuration including the above-described preferred configuration, the current non-injection inner region and the current non-injection outer region can be configured to be formed by ion implantation into the laminate structure. For the sake of convenience, the light-emitting element having such a configuration is referred to as the 'light-emitting element of the second-A configuration' and the 'light-emitting element of the third-A configuration'. And in this case, the ion species can be configured to be at least one type of ion (that is, one type of ion or two or more types of ions) selected from the group consisting of boron, proton, phosphorus, arsenic, carbon, nitrogen, fluorine, oxygen, germanium, and silicon.

[0124] Alternatively, in the light-emitting element of the second configuration or the light-emitting element of the third configuration including the above-described preferred configuration, the current non-injection inner region and the current non-injection outer region can be configured to be formed by plasma irradiation on the second surface of the second compound semiconductor layer, or by ashing treatment on the second surface of the second compound semiconductor layer, or by reactive ion etching treatment on the second surface of the second compound semiconductor layer. For the sake of convenience, the light-emitting element having such a configuration is referred to as the 'light-emitting element of the second-B configuration' and the 'light-emitting element of the third-B configuration'. In these processes, since the current non-injection inner region and the current non-injection outer region are exposed to plasma particles, the conductivity of the second compound semiconductor layer deteriorates, and the current non-injection inner region and the current non-injection outer region become in a high-resistance state. That is, the current non-injection inner region and the current non-injection outer region can be configured to be formed by exposure of the second surface of the second compound semiconductor layer to plasma particles. Specific examples of the plasma particles include argon, oxygen, nitrogen, and the like.

[0125] Alternatively, in the light-emitting element of the second configuration or the light-emitting element of the third configuration including the above-described preferred configuration, the second light reflection layer can be configured to have a region that reflects or scatters the light from the first light reflection layer toward the outside of the resonator structure formed by the first light reflection layer and the second light reflection layer. For convenience, the light-emitting element having such a configuration is referred to as the 'light-emitting element of the second-C configuration' and the 'light-emitting element of the third-C configuration'. Specifically, the region of the second light reflection layer located above the side wall of the mode loss action site (the side wall of the opening provided in the mode loss action site) has a forward-tapered inclination, or alternatively, has a region that is convexly curved toward the first light reflection layer or the like. Alternatively, in the light-emitting element of the second configuration or the light-emitting element of the third configuration including the above-described preferred form, the first light reflection layer can be configured to have a region that reflects or scatters the light from the second light reflection layer toward the outside of the resonator structure formed by the first light reflection layer and the second light reflection layer. Specifically, a forward-tapered inclination may be formed in a part of the region such as the first light reflection layer, or a convex curved portion may be formed toward the second light reflection layer. Alternatively, the region of the first light reflection layer or the like located above the side wall of the mode loss action site (the side wall of the opening provided in the mode loss action site) may have a forward-tapered inclination or alternatively, may have a region that is convexly curved toward the second light reflection layer. Further, by scattering light at the boundary (side wall edge portion) between the top surface of the mode loss action site and the side wall of the opening provided in the mode loss action site, it is also possible to configure to scatter light toward the outside of the resonator structure formed by the first light reflection layer and the second light reflection layer.

[0126] In the light-emitting element of the second-A configuration, the light-emitting element of the second-B configuration, or the light-emitting element of the second-C configuration described above, the optical distance from the light-emitting layer in the current injection region to the second surface of the second compound semiconductor layer is L 2 and the optical distance from the light-emitting layer in the mode loss action region to the top surface of the mode loss action site is L 0 When L 0 > L 2 It can be configured to satisfy. Also, in the light-emitting element of the 3-A configuration, the light-emitting element of the 3-B configuration, or the light-emitting element of the 3-C configuration described above, the optical distance from the light-emitting layer in the current injection region to the first surface of the first compound semiconductor layer is L 1 ’, and the optical distance from the light-emitting layer in the mode loss action region to the top surface of the mode loss action site is L 0 ’. When L 0 ’ > L 1 ’ It can be configured to satisfy. Furthermore, in the light-emitting element of the 2-A configuration, the light-emitting element of the 3-A configuration, the light-emitting element of the 2-B configuration, the light-emitting element of the 3-B configuration, the light-emitting element of the 2-C configuration, or the light-emitting element of the 3-C configuration described above, including these configurations, the light having the generated higher-order mode is dissipated outward by the mode loss action region toward the outside of the resonator structure composed of the first light reflection layer and the second light reflection layer, so that the oscillation mode loss can be increased. That is, the light field intensities of the generated fundamental mode and higher-order modes decrease as they move away from the Z-axis within the orthographic image of the mode loss action region due to the presence of the mode loss action region that affects the increase and decrease of the oscillation mode loss. However, the mode loss of the higher-order mode is greater than the decrease in the light field intensity of the fundamental mode, so the fundamental mode can be further stabilized, and the mode loss can be suppressed compared to the case where there is no current non-injection / inner region, so that the threshold current can be reduced.

[0127] Also, in the light-emitting element of the 2-A configuration, the light-emitting element of the 3-A configuration, the light-emitting element of the 2-B configuration, the light-emitting element of the 3-B configuration, the light-emitting element of the 2-C configuration, or the light-emitting element of the 3-C configuration described above, the mode loss action site can be configured to be made of a dielectric material, a metal material, or an alloy material. As the dielectric material, SiO X , SiN X , AlN X , AlO X , TaO X , ZrO Xcan be exemplified, and as the metal material or alloy material, titanium, gold, platinum, or their alloys can be exemplified, but it is not limited to these materials. Light can be absorbed by the mode loss action site composed of these materials to increase the mode loss. Alternatively, even if the light is not directly absorbed, the mode loss can be controlled by disturbing the phase. In this case, the mode loss action site is made of a dielectric material, and the optical film thickness t of the mode loss action site 0 is a value that deviates from an integer multiple of 1 / 4 of the wavelength λ of the light generated in the light-emitting element 0 . That is, the phase of the light that circulates in the resonator and forms a standing wave can be disturbed at the mode loss action site to destroy the standing wave and give a corresponding mode loss. Alternatively, the mode loss action site is made of a dielectric material, and the optical film thickness t of the mode loss action site (with a refractive index of n 0 ) 0 can be configured to be an integer multiple of 1 / 4 of the wavelength λ of the light generated in the light-emitting element 0 . That is, the optical film thickness t of the mode loss action site 0 can be configured to be a thickness that does not disturb the phase of the light generated in the light-emitting element and does not destroy the standing wave. However, it does not necessarily have to be exactly an integer multiple of 1 / 4, and (λ 0 / 4n 0 )×m-(λ 0 / 8n 0 )≦t 0 ≦(λ 0 / 4n 0 )×2m+(λ 0 / 8n 0 ) (E) just needs to be satisfied. Alternatively, by configuring the mode loss action site to be composed of a dielectric material, a metal material, or an alloy material, the light passing through the mode loss action site can be disturbed in phase or absorbed by the mode loss action site. By adopting these configurations, the control of the oscillation mode loss can be performed with a higher degree of freedom, and the design freedom of the light-emitting element can be further increased.

[0128] Alternatively, in the light-emitting element of the second configuration including the above-described preferred configuration, a convex portion is formed on the second surface side of the second compound semiconductor layer, The mode loss action site can be formed on the region of the second surface of the second compound semiconductor layer surrounding the convex portion. For the sake of convenience, the light-emitting element having such a configuration is referred to as the 'light-emitting element of the second-D configuration'. The convex portion occupies the current injection region and the current non-injection / inner region. And in this case, the optical distance from the light-emitting layer in the current injection region to the second surface of the second compound semiconductor layer is L 2 and the optical distance from the light-emitting layer in the mode loss action region to the top surface of the mode loss action site is L 0 When this is the case, L 0 < L 2 a configuration that satisfies < can be adopted. Furthermore, in these cases, the light having the generated higher-order mode can be confined in the current injection region and the current non-injection / inner region by the mode loss action region, and thus, a configuration in which the oscillation mode loss is reduced can be adopted. That is, the light field intensities of the generated fundamental mode and higher-order mode increase within the orthographic images of the current injection region and the current non-injection / inner region due to the presence of the mode loss action region that affects the increase and decrease of the oscillation mode loss. Furthermore, in these cases, the mode loss action site can be configured to be made of a dielectric material, a metal material, or an alloy material. Here, as the dielectric material, metal material, or alloy material, the various materials described above can be cited.

[0129] Alternatively, in the light-emitting element of the third configuration including the above-described preferred configuration, a convex portion is formed on the first surface side of the first compound semiconductor layer, The mode loss action site is formed on the region of the first surface of the first compound semiconductor layer surrounding the convex portion, or alternatively, the mode loss action site can be configured to be composed of the region of the first compound semiconductor layer surrounding the convex portion. For convenience, the light-emitting device having such a configuration is referred to as the 'light-emitting device of the 3-D configuration'. The convex portion coincides with the orthographic projection image of the current injection region and the non-current injection / inner region. And in this case, the optical distance from the light-emitting layer in the current injection region to the first surface of the first compound semiconductor layer is L 1 ’, and the optical distance from the light-emitting layer in the mode loss action region to the top surface of the mode loss action site is L 0 ’. When L 0 ’ < L 1 ’ is satisfied, and furthermore, in these cases, a convex portion is formed on the first surface side of the first compound semiconductor layer, and the mode loss action site can be configured to be composed of the region of the first surface of the first compound semiconductor layer surrounding the convex portion. Furthermore, in these cases, the light having the generated higher-order mode can be confined in the current injection region and the non-current injection / inner region by the mode loss action region, so that the oscillation mode loss can be reduced. Furthermore, in these cases, the mode loss action site can be configured to be made of a dielectric material, a metal material, or an alloy material. Here, as the dielectric material, the metal material, or the alloy material, the various materials described above can be cited.

[0130] Furthermore, in the light-emitting device having the concave mirror portion of the present disclosure including the preferred forms and configurations (including the light-emitting device of the first configuration to the light-emitting device of the third configuration) described above, in the same manner as described in Example 4, in the laminated structure including the second electrode, at least two light absorption material layers can be formed in parallel with the virtual plane occupied by the light-emitting layer. Here, for convenience, the light-emitting device having such a configuration is referred to as the 'light-emitting device of the 4-D configuration'.

[0131] In the light-emitting device of the 4-D configuration, it is preferable that at least four light absorption material layers are formed in the same manner as described in Example 4.

[0132] In the light-emitting element of the fourth configuration including the above-described preferred configuration, similar to that described in Example 4, the oscillation wavelength (the wavelength of light mainly emitted from the light-emitting element and being the desired oscillation wavelength) is λ 0 , the equivalent refractive index of the entire portion of the two-layer light absorption material layer and the laminated structure portion located between the light absorption material layers is n eq , the distance between the light absorption material layers is L Abs , it is preferable to satisfy the above-described formulas (B-1), (B-2), (B-3), and (B-4).

[0133] Furthermore, in the light-emitting element of the fourth configuration including the above-described various preferred configurations, similar to that described in Example 4, the thickness of the light absorption material layer is preferably λ 0 / (4·n eq ) or less. As the lower limit value of the thickness of the light absorption material layer, 1 nm can be exemplified.

[0134] Furthermore, in the light-emitting element of the fourth configuration including the above-described various preferred configurations, similar to that described in Example 4, the light absorption material layer can be configured to be located at the lowest amplitude portion generated in the standing wave of light formed inside the laminated structure.

[0135] Furthermore, in the light-emitting element of the fourth configuration including the above-described various preferred configurations, similar to that described in Example 4, the light-emitting layer can be configured to be located at the maximum amplitude portion generated in the standing wave of light formed inside the laminated structure.

[0136] Furthermore, in the light-emitting element of the fourth configuration including the above-described various preferred configurations, similar to that described in Example 4, the light absorption material layer can be configured to have a light absorption coefficient that is twice or more the light absorption coefficient of the compound semiconductor constituting the laminated structure.

[0137] Furthermore, in the light-emitting element of the fourth configuration including the above-described various preferred configurations, similar to that described in Example 4, the light absorption material layer is composed of at least one material selected from the group consisting of a compound semiconductor material having a narrower band gap than the compound semiconductor constituting the laminated structure, a compound semiconductor material doped with impurities, a transparent conductive material, and a light reflection layer constituent material having light absorption characteristics.

[0138] Furthermore, in the light-emitting element having the concave mirror portion of the present disclosure including the preferred forms and configurations (including the light-emitting element of the first configuration to the light-emitting element of the fourth configuration) described above, a substrate for manufacturing the light-emitting element (specifically, a compound semiconductor substrate) can be disposed between the first surface of the first compound semiconductor layer and the first light reflection layer or the like. Here, for convenience, the light-emitting element having such a configuration is referred to as the 'light-emitting element of the fifth configuration'. In this case, the substrate for manufacturing the light-emitting element can be composed of a GaN substrate. Note that, as the thickness of the substrate for manufacturing the light-emitting element, 5×10 -5 m to 1×10 -4 m can be exemplified, but it is not limited to such values. And, in the light-emitting element of the fifth configuration including such a configuration, the concave mirror portion composed of the first light reflection layer or the like is composed of a base portion formed of a protruding portion of the substrate for manufacturing the light-emitting element, and a film thickness modulation layer and a multilayer light reflection film formed on at least a part of the surface of the base portion. Here, for convenience, the light-emitting element having such a configuration is referred to as the 'light-emitting element of the fifth-A configuration'. Alternatively, the concave mirror portion composed of the first light reflection layer or the like can be composed of a base portion formed on the substrate for manufacturing the light-emitting element, and a film thickness modulation layer and a multilayer light reflection film formed on at least a part of the surface of the base portion. Here, for convenience, the light-emitting element having such a configuration is referred to as the 'light-emitting element of the fifth-B configuration'. The material constituting the base portion in the light-emitting element of the fifth-A configuration is, for example, a GaN substrate. As the GaN substrate, any of a polar substrate, an antipolar substrate, and a nonpolar substrate may be used. On the other hand, as the material constituting the base portion in the light-emitting element of the fifth-B configuration, TiO 2 、Ta 2 O 5 、SiO 2Examples thereof include transparent dielectric materials such as, silicone resins, and epoxy resins.

[0139] Alternatively, in the light-emitting device having the concave mirror portion of the present disclosure including the preferred forms and configurations (including the light-emitting device of the first configuration to the light-emitting device of the fourth configuration) described above, a configuration may be adopted in which a first light reflection layer or the like is formed on the first surface of the first compound semiconductor layer. Here, for convenience, the light-emitting device having such a configuration is referred to as the "light-emitting device of the sixth configuration."

[0140] Furthermore, in the light-emitting device having the concave mirror portion of the present disclosure including the preferred forms and configurations (including the light-emitting device of the first configuration to the light-emitting device of the sixth configuration) described above, the value of the thermal conductivity of the laminated structure can be set to be higher than the value of the thermal conductivity of the first light reflection layer or the like. The value of the thermal conductivity of the dielectric material constituting the first light reflection layer or the like is generally about 10 watts / (m·K) or less. On the other hand, the value of the thermal conductivity of the GaN-based compound semiconductor constituting the laminated structure is about 50 watts / (m·K) to about 100 watts / (m·K).

[0141] Furthermore, in the light-emitting device having the concave mirror portion of the present disclosure including the preferred forms and configurations (including the light-emitting device of the first configuration to the light-emitting device of the sixth configuration) described above, the concave mirror portion of the light-emitting device (specifically, the radius r' in the concave mirror portion composed of the first light reflection layer or the like DBR of the effective region) DBR When the radius of curvature is R DBR ≦ 1×10 -3 m, preferably, 1×10 -5 m ≦ R DBR ≦ 1×10 -3 m, more preferably, 1×10 -5 m ≦ R DBR ≦ 1×10 -4 m, a configuration that satisfies the above can be adopted. Also, although 1×10 -5 m ≦ L OR is satisfied, preferably 1×10 -5 m ≦ L OR ≦ 5×10 -4 m, more preferably, 1×10 -5 m ≦ LOR ≦ 1 × 10 -4 It is desirable to satisfy m.

[0142] Furthermore, in the light-emitting element having the concave mirror portion of the present disclosure including the preferred forms and configurations described above (including the light-emitting elements of the first configuration to the sixth configuration), a convex-shaped portion is formed around the first light reflection layer and the like, and the first light reflection layer can be configured not to protrude from the convex-shaped portion, whereby the first light reflection layer can be protected. That is, since the first light reflection layer is provided in a state recessed from the convex-shaped portion, for example, even if some object contacts the convex-shaped portion, this object does not contact the first light reflection layer, and the first light reflection layer can be reliably protected.

[0143] Also, in the light-emitting element having the concave mirror portion of the present disclosure including the preferred forms and configurations described above (including the light-emitting elements of the first configuration to the sixth configuration), among the materials constituting various compound semiconductor layers (including the substrate for manufacturing a light-emitting element made of a compound semiconductor substrate) located between the light-emitting layer and the first light reflection layer and the like, it is preferable that there is no modulation of the refractive index of 10% or more (no refractive index difference of 10% or more based on the average refractive index of the laminated structure), whereby the generation of disturbance in the optical field in the resonator can be suppressed.

[0144] Hereinafter, a light-emitting element having the concave mirror portion of Example 7 will be described. Example 7 relates to a light-emitting element of the fifth-A configuration. The light-emitting elements of Example 7 or Examples 8 to 18 described later are, depending on the configuration, more specifically, a surface-emitting laser element (vertical cavity laser, VCSEL) that emits laser light from the top surface of the second compound semiconductor layer through the second light reflection layer, or more specifically, a surface-emitting laser element (vertical cavity laser, VCSEL) that emits laser light from the top surface of the first compound semiconductor layer through the first light reflection layer. A schematic partial end view of the light-emitting element of Example 7 is shown in FIG. 13.

[0145] In the light-emitting element of Example 7 or the light-emitting elements of Examples 8 to 18 described later, the first light reflection layer 41 and the film thickness modulation layer 80 have a concave mirror portion 43, and the second light reflection layer 42 has a flat shape. And when the resonator length is L OR and, 1×10 -5 m≦L OR is satisfied.

[0146] In addition, in the drawings related to Examples 7 to 18, in order to simplify the drawings, except for FIG. 13, in the drawings, the laminated structure of the first light reflection layer 41 and the film thickness modulation layer 80 is shown as one layer with the reference numeral "41 + 80", and the laminated structure of the multilayer light reflection film 46 and the film thickness modulation layer 80 is shown as one layer.

[0147] Also, in the light-emitting element of Example 7, when the first light reflection layer 41 and the film thickness modulation layer 80 are cut in a virtual plane including the lamination direction of the laminated structure 20, a part of the concave mirror portion 43 composed of the first light reflection layer 41 and the film thickness modulation layer 80 (the effective region 44 in the concave mirror portion 43 composed of the first light reflection layer 41 and the film thickness modulation layer 80) The figure drawn by the interface 43a facing the laminated structure 20 (specifically, the interface 43a between the laminated structure 20 and the film thickness modulation layer 80) is a part of a circle or a part of a parabola. In addition, the shape (the figure of the cross-sectional shape) of the portion of the concave mirror portion 43 located outside the effective region 44 does not have to be a part of a circle or a part of a parabola.

[0148] And, the concave mirror portion 43 composed of the first light reflection layer 41 and the film thickness modulation layer 80 includes a base portion 45A formed by a protruding portion 11a' on the first surface 11a of the substrate 11 for manufacturing a light-emitting element made of a compound semiconductor substrate, and at least a part of the surface of the base portion 45A (specifically, the surface of the base portion 45A) It is composed of the formed film thickness modulation layer 80 and the multilayer light reflection film 46. Furthermore, the radius of curvature of the concave mirror portion 43 (specifically, the effective region 44 with a radius r' in the concave mirror portion 43 composed of the first light reflection layer 41 and the film thickness modulation layer 80) is R DBR and when, DBR is, R DBR ≦1×10 -3 m is satisfied. Specifically, but not limited to, L OR = 50 μm R DBR = 70 μm r’ DBR = 20 μm can be exemplified. Also, the wavelength (oscillation wavelength) λ of the desired light mainly emitted from the light-emitting element 0 is taken as λ 0 = 450 nm can be exemplified.

[0149] Here, if the distance from the light-emitting layer 23 to the interface between the base 45A and the multilayer light reflection film 46 is T 0 then the function x = f(z) of the ideal parabola can be expressed as x = z 2 / t 0 h DBR = r’ DBR 2 / 2T 0 It goes without saying that even if the figure drawn by the interface 43a is a parabola that deviates from such an ideal parabola, it may be a parabola that is a part of the parabola.

[0150] Also, the value of the thermal conductivity of the laminated structure 20 is higher than the values of the thermal conductivities of the first light reflection layer 41 and the film thickness modulation layer 80. The value of the thermal conductivity of the dielectric material constituting the first light reflection layer 41 and the film thickness modulation layer 80 is about 10 watts / (m·K) or less. On the other hand, the value of the thermal conductivity of the GaN-based compound semiconductor constituting the laminated structure 20 is about 50 watts / (m·K) to about 100 watts / (m·K).

[0151] Hereinafter, with reference to FIGS. 14A, 14B, 15, 16, 17, 18, and 19, which are schematic partial end views of the laminated structure and the like, a method for manufacturing the light-emitting element of Example 7 will be described.

[0152] [Process - 700] First, on the second surface 11b of the light-emitting element manufacturing substrate 11 made of a compound semiconductor substrate having a thickness of about 0.4 mm A first compound semiconductor layer 21 having a first surface 21a and a second surface 21b facing the first surface 21a, A light-emitting layer (active layer) 23 facing the second surface 21b of the first compound semiconductor layer 21, and A second compound semiconductor layer 22 having a first surface 22a facing the light-emitting layer 23 and a second surface 22b facing the first surface 22a are stacked to form a stacked structure 20 made of a GaN-based compound semiconductor. Specifically, based on an epitaxial growth method by a well-known MOCVD method, the first compound semiconductor layer 21, the light-emitting layer 23, and the second compound semiconductor layer 22 are sequentially formed on the second surface 11b of the substrate 11 for manufacturing a light-emitting element, whereby the stacked structure 20 can be obtained (see Fig. 14A).

[0153] [Process - 710] Next, based on a combination of a film-forming method such as a CVD method, a sputtering method, or a vacuum evaporation method and a wet etching method or a dry etching method, an insulating layer (current constriction layer) 34 made of SiO 2 having an opening 34A is formed on the second surface 22b of the second compound semiconductor layer 22 (see Fig. 14B). The insulating layer 34 having the opening 34A defines a current constriction region (current injection region 61A and current non-injection region 61B). That is, the current injection region 61A is defined by the opening 34A.

[0154] To obtain a current constriction region, as described above, an insulating material (for example, SiO X or SiN X or AlO XAn insulating layer (current constriction layer) may be formed, or alternatively, the second compound semiconductor layer 22 may be etched by the RIE method or the like to form a mesa structure, or alternatively, a part of the stacked second compound semiconductor layers 22 may be partially oxidized from the lateral direction to form a current constriction region, or an impurity may be ion-implanted into the second compound semiconductor layer 22 to form a region with reduced conductivity, or these may be appropriately combined. However, the second electrode 32 needs to be electrically connected to the portion of the second compound semiconductor layer 22 through which current flows due to current constriction.

[0155] [Process - 720] Thereafter, a second electrode 32 and a second light reflection layer 42 are formed on the second compound semiconductor layer 22. Specifically, from the second surface 22b of the second compound semiconductor layer 22 exposed at the bottom of the opening 34A (current injection region 61A) over the insulating layer 34, for example, the second electrode 32 is formed based on the lift-off method, and further, a pad electrode 33 is formed based on a combination of a film-forming method such as sputtering or vacuum evaporation and a patterning method such as wet etching or dry etching. Next, from above the second electrode 32 over the pad electrode 33, a second light reflection layer 42 is formed based on a combination of a film-forming method such as sputtering or vacuum evaporation and a patterning method such as wet etching or dry etching. The second light reflection layer 42 above the second electrode 32 has a flat shape. In this way, the structure shown in FIG. 15 can be obtained.

[0156] [Process - 730] Next, the second light reflection layer 42 is fixed to the support substrate 49 via the bonding layer 48 (see FIG. 16). Specifically, the second light reflection layer 42 is fixed to the support substrate 49 composed of a sapphire substrate using the bonding layer 48 made of an adhesive.

[0157] [Process - 740] Next, the substrate 11 for manufacturing a light-emitting element is thinned based on a mechanical polishing method or a CMP method, and further, the first surface 11a of the substrate 11 for manufacturing a light-emitting element is mirror-finished (see FIG. 17). The value of the surface roughness Ra of the first surface 11a of the substrate 11 for manufacturing a light-emitting element is preferably 10 nm or less. Then, a base portion 45A composed of a protruding portion 11a' is formed on the exposed surface (the first surface 11a) of the substrate 11 for manufacturing a light-emitting element. Specifically, a patterned resist layer is formed on the first surface 11a of the substrate 11 for manufacturing a light-emitting element on which the base portion 45A is to be formed, and the resist layer is heated to reflow the resist layer to obtain a resist pattern. The resist pattern is given the same shape (or a similar shape) as the shape of the protruding portion 11a'. Then, the resist pattern and the first surface 11a of the substrate 11 for manufacturing a light-emitting element are etched back using an RIE method or the like, whereby the base portion 45A composed of the protruding portion 11a' can be formed on the exposed surface (the first surface 11a) of the substrate 11 for manufacturing a light-emitting element (see FIG. 18).

[0158] [Process - 750] Thereafter, a film thickness modulation layer 80 and a multilayer light reflection film 46 are formed on at least a part of the base portion 45A. Specifically, the film thickness modulation layer 80 and the multilayer light reflection film 46 are formed based on a well-known method such as a sputtering method or a vacuum evaporation method from the exposed surface (the first surface 11a) of the substrate 11 for manufacturing a light-emitting element over the base portion 45A. Then, unnecessary portions of the multilayer light reflection film 46 and the film thickness modulation layer 80 are removed based on a patterning method such as a wet etching method or a dry etching method to obtain the film thickness modulation layer 80 and the first light reflection layer 41 (see FIG. 19). After that, a first electrode 31 is formed on the first surface 11a of the substrate 11 for manufacturing a light-emitting element based on a combination of a film formation method such as a sputtering method or a vacuum evaporation method and a patterning method such as a wet etching method or a dry etching method, whereby a first electrode 31 electrically connected to the first compound semiconductor layer 21 can be obtained.

[0159] [Process - 760] Then, the support substrate 49 is peeled off. Thus, the structure shown in FIG. 13 can be obtained. Thereafter, a so-called element isolation is performed to separate the light-emitting elements, and the side surface and the exposed surface of the laminated structure are, for example, SiO2 It is coated with an insulating film composed of... Next, by packaging and sealing, the light-emitting element of Example 7 is completed.

[0160] In addition, in [Process - 740], after thinning the substrate 11 for manufacturing the light-emitting element and further performing a mirror finish, the support substrate 49 may be peeled off.

[0161] Also, as a modified example of the light-emitting element of Example 7, in [Process - 740], after thinning the substrate 11 for manufacturing the light-emitting element and further performing a mirror finish, and before forming the base portion 45A composed of the protruding portion 11a' on the exposed surface (the first surface 11a) of the substrate 11 for manufacturing the light-emitting element, a recess 11a” is formed in the region of the exposed surface (the first surface 11a) of the substrate 11 for manufacturing the light-emitting element where the base portion 45A is to be formed. A patterned resist layer is formed in the recess 11a”. By heating the resist layer, the resist layer is reflowed to obtain a resist pattern. The same shape (or a similar shape) as the shape of the protruding portion 11a' is imparted to the resist pattern. Then, by etching back the resist pattern and the portion of the recess 11a” using an RIE method or the like, the base portion 45A composed of the protruding portion 11a' may be formed in the recess 11a” on the exposed surface (the first surface 11a) of the substrate 11 for manufacturing the light-emitting element (see Fig. 20). Next, the film thickness modulation layer 80 and the multilayer light reflection film 46 are formed on the entire surface including the top of the base portion 45A based on a well-known method such as sputtering or vacuum evaporation. Then, by removing the unnecessary portions of the multilayer light reflection film 46 and the film thickness modulation layer 80 based on a patterning method such as a wet etching method or a dry etching method, the film thickness modulation layer 80 and the first light reflection layer 41 can be obtained. That is, a convex-shaped portion 11A is formed around the film thickness modulation layer 80 and the first light reflection layer 41, and the first light reflection layer 41 does not protrude from the convex-shaped portion 11A (which is composed of the exposed surface (the first surface 11a) of the substrate 11 for manufacturing the light-emitting element), thereby protecting the first light reflection layer 41.

[0162] Alternatively, in [Process - 740], while forming a base portion 45A composed of a protruding portion 11a' on the exposed surface (the first surface 11a) of the substrate 11 for manufacturing a light - emitting element made of a compound semiconductor substrate, a protruding portion may be formed on the exposed surface (the first surface 11a) of the substrate 11 for manufacturing a light - emitting element so as to surround the base portion 45A while being spaced apart from the base portion 45A. Specifically, a patterned resist layer is formed on the first surface 11a of the substrate 11 for manufacturing a light - emitting element on which the base portion 45A is to be formed, and the resist layer is re - flowed by heating the resist layer to obtain a resist pattern. The resist pattern is given the same shape (or a similar shape) as that of the protruding portion 11a'. At the same time, a resist layer is formed on a portion of the first surface 11a of the substrate 11 for manufacturing a light - emitting element where the protruding portion is to be formed so as to surround the resist pattern while being spaced apart from the resist pattern. Then, by etching back the resist pattern, the resist layer, and the first surface 11a of the substrate 11 for manufacturing a light - emitting element using the RIE method or the like, a base portion 45A composed of a protruding portion 11a' can be formed on the exposed surface (the first surface 11a) of the substrate 11 for manufacturing a light - emitting element, and at the same time, the protruding portion can be formed. Protruding portions are formed around the film - thickness modulation layer 80 and the first light - reflection layer 41, and the first light - reflection layer 41 does not protrude from the protruding portion (which is composed of the exposed surface (the first surface 11a) of the substrate 11 for manufacturing a light - emitting element), whereby the first light - reflection layer 41 can be protected.

[0163] Alternatively, in the above - mentioned [Process - 750], after forming the film - thickness modulation layer 80 and the multilayer light - reflection film 46 on at least a part of the base portion 45A and patterning them to obtain the film - thickness modulation layer 80 and the first light - reflection layer 41, a convex - shaped portion 11A surrounding the film - thickness modulation layer 80 and the first light - reflection layer 41 may be formed on the first surface 11a of the substrate 11 for manufacturing a light - emitting element (see Fig. 21). The convex - shaped portion 11A may be composed of, for example, an insulating material or a metallic material. In this way, a convex - shaped portion 11A is formed around the film - thickness modulation layer 80 and the first light - reflection layer 41, and the first light - reflection layer 41 does not protrude from the convex - shaped portion 11A, whereby the first light - reflection layer 41 can be protected.

[0164] In the light-emitting element of Example 7, the first light reflection layer and the film thickness modulation layer have a concave mirror portion. Therefore, the resonator length L OR is 1×10 -5 m or more, and as a result, it is possible to avoid an increase in diffraction loss, and thus laser oscillation can be surely performed. Also, since the resonator length L OR can be 1×10 -5 m or more, the problem of thermal saturation can be alleviated. Further, since the resonator length L OR can be 1×10 -5 m or more, the tolerance of the manufacturing process of the light-emitting element is increased, and as a result, the yield can be improved.

[0165] Also, except for Example 10 described later, in the manufacturing process of the light-emitting element, a GaN substrate is used, but a GaN-based compound semiconductor is not formed based on a method of epitaxially growing in the lateral direction such as the ELO method. Therefore, as the GaN substrate, not only a polar GaN substrate but also an antipolar GaN substrate and a nonpolar GaN substrate can be used. When a polar GaN substrate is used, the luminous efficiency tends to decrease due to the effect of the piezoelectric field in the light-emitting layer, but if a nonpolar GaN substrate or an antipolar GaN substrate is used, such problems can be solved or alleviated.

[0166] Also, between [Process - 740] and [Process - 750], a smooth surface can be obtained by applying and curing a transparent material to the exposed surface (the first surface 11a) of the light-emitting element manufacturing substrate 11 formed of the protruding portion 11a'. By forming the transparent material, the occurrence of optical loss, for example, the occurrence of scattering loss due to the exposed surface (the first surface 11a) of the light-emitting element manufacturing substrate 11 can be more surely suppressed. Examples of the transparent material include epoxy-based resins, silicone-based resins, acrylic-based resins, and silica, and the thickness can be 100 nm or less, for example, about 10 nm.

Example

[0167] Example 8 is a modification of Example 7 and relates to a light-emitting element having a 5-B configuration. In the light-emitting element of Example 8, a schematic partial end view of which is shown in FIG. 22, a concave mirror portion 43 composed of a first light reflection layer 41 and a film thickness modulation layer 80 is composed of a base portion 45B formed by a protruding portion 45c formed on the light-emitting element manufacturing substrate 11 (specifically, on the first surface 11a of the light-emitting element manufacturing substrate 11 made of a compound semiconductor substrate), and a film thickness modulation layer 80 and a multilayer light reflection film 46 formed on at least a part of the base portion 45B (specifically, the surface of the base portion 45B). As the material constituting the base portion 45B (protruding portion 45c), TiO 2 、Ta 2 O 5 、SiO 2 and other transparent dielectric materials, silicone resins, epoxy resins, etc. can be mentioned.

[0168] In the light-emitting element of Example 8, in the same process as [Process - 740] of Example 7, after thinning the light-emitting element manufacturing substrate 11 and performing mirror finishing, a base portion 45B composed of a protruding portion 45c is formed on the exposed surface (first surface 11a) of the light-emitting element manufacturing substrate 11. Specifically, on the exposed surface (first surface 11a) of the light-emitting element manufacturing substrate 11, for example, a TiO 2 layer or a Ta 2 O 5 layer is formed, and then a patterned resist layer is formed on the TiO 2 layer or Ta 2 O 5 layer on which the base portion 45B is to be formed. By heating the resist layer, the resist layer is reflowed to obtain a resist pattern. The resist pattern is given the same shape (or a similar shape) as the shape of the protruding portion 45c. Then, the resist pattern and the TiO 2 layer or Ta 2 O 5By etching back the layer, a base portion 45B composed of a protruding portion 45c can be formed on the exposed surface (first surface 11a) of the substrate 11 for manufacturing a light-emitting element. Next, based on a well-known method, a film thickness modulation layer 80 and a multilayer light reflection film 46 are formed from the exposed surface (first surface 11a) of the substrate 11 for manufacturing a light-emitting element over the base portion 45B. Thereafter, unnecessary portions of the multilayer light reflection film 46 and the film thickness modulation layer 80 are removed to obtain the film thickness modulation layer 80 and the first light reflection layer 41, and then a first electrode 31 is formed on the first surface 11a of the substrate 11 for manufacturing a light-emitting element, whereby a first electrode 31 electrically connected to the first compound semiconductor layer 21 can be obtained.

[0169] Except for the above points, the configuration and structure of the light-emitting element of Example 8 can be the same as those of the light-emitting element of Example 7, so detailed description is omitted. Incidentally, the modification example of the light-emitting element of Example 7 can also be applied to Example 8.

Example

[0170] Example 9 is also a modification of Example 7 or Example 8 and relates to a light-emitting element of the sixth configuration. In the light-emitting element of Example 9, a schematic partial end view of which is shown in FIG. 23, a film thickness modulation layer 80 and a first light reflection layer 41 are formed on the first surface 21a of the first compound semiconductor layer 21. In the manufacture of the light-emitting element of Example 9, in the same process as [Process - 740] of Example 7, the substrate 11 for manufacturing a light-emitting element is removed to expose the first surface 21a of the first compound semiconductor layer 21. Then, in the same manner as in Example 7, a patterned resist layer is formed on the first surface 21a of the first compound semiconductor layer 21 on which the base portion 45D is to be formed, and the resist layer is heated to reflow the resist layer to obtain a resist pattern. The resist pattern is given the same shape (or a similar shape) as the shape of the protruding portion 21d. Then, by etching back the resist pattern and the first surface 21a of the first compound semiconductor layer 21, a base portion 45D composed of a protruding portion 21d can be formed on the first surface 21a of the first compound semiconductor layer 21. Alternatively, in a modification example of the light-emitting element of Example 9, a schematic partial end view of which is shown in FIG. 24, on the first surface 21a of the first compound semiconductor layer 21, for example, TiO 2 layer or Ta2 O 5 Form a layer, and then, TiO to form the base 45E 2 layer or Ta 2 O 5 Form a patterned resist layer on the layer or Ta layer, and heat the resist layer to reflow the resist layer to obtain a resist pattern. The resist pattern is given the same shape (or a similar shape) as the shape of the protrusion 21e. Then, by etching back the resist pattern and the TiO 2 layer or Ta 2 O 5 layer, a base 45E composed of the protrusion 21e can be formed on the first surface 21a of the first compound semiconductor layer 21.

[0171] Except for the above points, the configurations and structures of the light-emitting elements of Example 9 and its modified examples can be the same as those of the light-emitting elements of Example 7 or Example 8, so detailed descriptions are omitted. Note that the support substrate 49 and the bonding layer 48 may not be removed and left as they are.

Example

[0172] Example 10 is a modification of Example 9. A schematic partial end view of the light-emitting element of Example 10 is substantially the same as FIG. 24, and the configuration and structure of the light-emitting element of Example 10 can be substantially the same as those of the light-emitting element of Example 9, so detailed descriptions are omitted.

[0173] In Example 10, first, a recess 43A for forming a concave mirror portion 43 is formed on the second surface 11b of the substrate 11 for manufacturing a light-emitting element. Then, after forming a first light reflection layer 41 composed of a film thickness modulation layer 80 and a multilayer light reflection film 46 on the second surface 11b of the substrate 11 for manufacturing a light-emitting element, a planarization film 47 is formed on the first light reflection layer 41, and the planarization film 47, the film thickness modulation layer 80, and the first light reflection layer 41 are subjected to a planarization process. While leaving the planarization film 47, the film thickness modulation layer 80, and the first light reflection layer 41, a part of the second surface 11b of the substrate 11 for manufacturing a light-emitting element is exposed (see FIG. 25A). The planar shapes of the first light reflection layer 41 and the film thickness modulation layer 80 are circular. However, the shapes of the first light reflection layer 41 and the film thickness modulation layer 80 are not limited thereto.

[0174] Next, on the substrate 11 for manufacturing a light-emitting element including the first light reflection layer 41 and the film thickness modulation layer 80, a laminated structure 20 is formed based on lateral growth by using a method of epitaxially growing in the lateral direction such as the ELO method (see FIG. 25B). Then, [Process - 710] and [Process - 720] of Example 7 are executed. Then, the substrate 11 for manufacturing a light-emitting element is removed, and a first electrode 31 is formed on the first surface 21a of the exposed first compound semiconductor layer 21. Alternatively, without removing the substrate 11 for manufacturing a light-emitting element, a first electrode 31 is formed on the first surface 11a of the substrate 11 for manufacturing a light-emitting element. Then, the light-emitting element is separated by performing so-called element isolation, and the side surface and the exposed surface of the laminated structure are coated with an insulating film made of, for example, SiO 2 and the like. Then, by packaging or sealing, the light-emitting element of Example 10 can be completed.

Example

[0175] Example 11 is a modification of Examples 7 to 10 and relates to a light-emitting element of the first configuration. As described above, the insulating layer 34 having the opening 34A defines a current constriction region (current injection region 61A and current non-injection region 61B). That is, the current injection region 61A is defined by the opening 34A. That is, in the light-emitting element of Example 11, the second compound semiconductor layer 22 is provided with a current injection region 61A and a current non-injection region 61B surrounding the current injection region 61A, and the shortest distance D from the area centroid point of the current injection region 61A to the boundary 61C between the current injection region 61A and the current non-injection region 61B CI satisfies the above-described formulas (C-1) and (C-2).

[0176] In the light-emitting element of Example 11, the radius r' of the effective region in the concave mirror portion 43 composed of the first light reflection layer 41 and the film thickness modulation layer 80 DBR is ω 0 ≦r’ DBR ≦20·ω 0 satisfies. Also, D CI ≧ω 0 satisfies. Furthermore, R DBR ≦1×10 -3 m satisfies. Specifically, D CI =4μm ω 0 =1.5μm L OR =50μm R DBR =60μm λ 0 =525nm can be exemplified. Also, 8 μm can be exemplified as the diameter of the opening 34A. As the GaN substrate, a substrate having a main surface with a c-plane inclined by about 75 degrees in the m-axis direction is used. That is, the GaN substrate has a semi-polar plane {20-21} plane as the main surface. Note that such a GaN substrate can also be used in other embodiments.

[0177] The deviation between the central axis (Z-axis) of the concave mirror portion 43 and the current injection region 61A in the XY plane direction causes deterioration of the characteristics of the light-emitting element. In many cases, both the patterning for forming the concave mirror portion 43 and the patterning for forming the opening 34A use lithography technology. In this case, their positional relationship often shifts within the XY plane depending on the performance of the exposure machine. In particular, the opening 34A (current injection region 61A) is positioned by alignment from the side of the second compound semiconductor layer 22. On the other hand, the concave mirror portion 43 is positioned by alignment from the side of the substrate 11 for manufacturing the light-emitting element. Therefore, in the light-emitting element of Example 11, by forming the opening 34A (current injection region 61) larger than the region where the light is narrowed by the concave mirror portion 43, a structure is realized in which even if a deviation occurs between the central axis (Z-axis) of the concave mirror portion 43 and the current injection region 61A in the XY plane direction, the oscillation characteristics are not affected.

[0178] That is, when the region where the light reflected by the first light reflection layer is condensed is not included in the current injection region corresponding to the region where the light-emitting layer has a gain by current injection, the induced emission of light from the carriers is inhibited, and thus, laser oscillation may be inhibited. However, by satisfying the above formulas (C-1) and (C-2), it is possible to ensure that the region where the light reflected by the first light reflection layer is condensed is included in the current injection region, and laser oscillation can be surely achieved.

Example

[0179] Example 12 is a modification of Examples 7 to 11 and relates to a light-emitting element of the second configuration, specifically, a light-emitting element of the second-A configuration. A schematic partial end view of the light-emitting element of Example 12 is shown in FIG. 26.

[0180] Incidentally, in order to control the current path (current injection region) of the current flowing between the first electrode and the second electrode, a current non-injection region is formed so as to surround the current injection region. In a GaAs-based surface-emitting laser element (a surface-emitting laser element composed of a GaAs-based compound semiconductor), a current non-injection region surrounding the current injection region can be formed by oxidizing the light-emitting layer from the outside along the XY plane. The region of the oxidized light-emitting layer (current non-injection region) has a lower refractive index than the non-oxidized region (current injection region). As a result, the optical path length of the resonator (represented by the product of the refractive index and the physical distance) is shorter in the current non-injection region than in the current injection region. And this brings about a kind of "lens effect", which has the effect of confining the laser light to the central part of the surface-emitting laser element. Generally, since light tends to spread due to the diffraction effect, the laser light reciprocating in the resonator gradually dissipates outside the resonator (diffraction loss), causing adverse effects such as an increase in the threshold current. However, the lens effect compensates for this diffraction loss, so an increase in the threshold current and the like can be suppressed.

[0181] However, in a light-emitting element composed of a GaN-based compound semiconductor, due to the material characteristics, it is difficult to oxidize the light-emitting layer from the outside (from the lateral direction) along the XY plane. Therefore, as described in Examples 7 to 11, an insulating layer 34 made of SiO 2 is formed on the second compound semiconductor layer 22 having an opening, and a second electrode 32 made of a transparent conductive material is formed on the insulating layer 34 from the second compound semiconductor layer 22 exposed at the bottom of the opening 34A, and a second light reflection layer 42 made of a laminated structure of an insulating material is formed on the second electrode 32. Thus, the current non-injection region 61B is formed by forming the insulating layer 34. And the portion of the second compound semiconductor layer 22 located within the opening 34A provided in the insulating layer 34 becomes the current injection region 61A.

[0182] When an insulating layer 34 is formed on the second compound semiconductor layer 22, the resonator length in the region where the insulating layer 34 is formed (current non-injection region 61B) is longer than the resonator length in the region where the insulating layer 34 is not formed (current injection region 61A) by the optical film thickness of the insulating layer 34. Therefore, an effect occurs in which the laser light reciprocating in the resonator formed by the two optical reflection layers 41 and 42 of the surface-emitting laser element (light-emitting element) diverges and dissipates outside the resonator. Such an effect is, for convenience, called the 'inverse lens effect'. As a result, oscillation mode loss occurs in the laser light, and there is a risk that the threshold current increases or the slope efficiency deteriorates. Here, the 'oscillation mode loss' is a physical quantity that increases or decreases the optical field intensity of the fundamental mode and higher-order modes in the oscillating laser light, and different oscillation mode losses are defined for each mode. Incidentally, the 'optical field intensity' is the optical field intensity as a function of the distance L from the Z axis in the XY plane. Generally, in the fundamental mode, it monotonically decreases as the distance L increases, but in the higher-order mode, it decreases while increasing or decreasing once or multiple times as the distance L increases (see the conceptual diagram in (A) of FIG. 28). In FIG. 28, the solid line indicates the optical field intensity distribution of the fundamental mode, and the broken line indicates the optical field intensity distribution of the higher-order mode. Also, in FIG. 28, the first optical reflection layer 41 and the film thickness modulation layer 80 are, for convenience, shown in a flat state, but actually have a concave mirror portion.

[0183] The light-emitting element of Example 12 or the light-emitting elements of Examples 13 to 16 described later are (A) A first compound semiconductor layer 21 having a first surface 21a and a second surface 21b facing the first surface 21a, A light-emitting layer (active layer) 23 facing the second surface 21b of the first compound semiconductor layer 21, and A second compound semiconductor layer 22 having a first surface 22a facing the light-emitting layer 23 and a second surface 22b facing the first surface 22a, A laminated structure 20 made of a GaN-based compound semiconductor in which (B) A mode loss action site (mode loss action layer) 54 provided on the second surface 22b of the second compound semiconductor layer 22 and constituting a mode loss action region 55 that acts on the increase or decrease of the oscillation mode loss, (C) A second electrode 32 formed across the mode loss action site 54 from above the second surface 22b of the second compound semiconductor layer 22, (D) A second light reflection layer 42 formed on the second electrode 32, (E) A first light reflection layer 41 and a film thickness modulation layer 80 provided on the first surface 21a side of the first compound semiconductor layer 21, and (F) A first electrode 31 electrically connected to the first compound semiconductor layer 21, is provided.

[0184] And in the stacked structure 20, a current injection region 51, a current non-injection / inner region 52 surrounding the current injection region 51, and a current non-injection / outer region 53 surrounding the current non-injection / inner region 52 are formed, and the orthographic image of the mode loss action region 55 and the orthographic image of the current non-injection / outer region 53 overlap. That is, the current non-injection / outer region 53 is located below the mode loss action region 55. Note that in a region sufficiently far from the current injection region 51 where current is injected, the orthographic image of the mode loss action region 55 and the orthographic image of the current non-injection / outer region 53 do not have to overlap. Here, in the stacked structure 20, current non-injection regions 52 and 53 where current is not injected are formed, but in the illustrated example, they are formed across a part of the second compound semiconductor layer 22 to the first compound semiconductor layer 21 in the thickness direction. However, the current non-injection regions 52 and 53 may be formed in the region on the second electrode side of the second compound semiconductor layer 22 in the thickness direction, may be formed in the entire second compound semiconductor layer 22, or may be formed in the second compound semiconductor layer 22 and the light emitting layer 23.

[0185] The mode loss action site (mode loss action layer) 54 is made of a dielectric material such as SiO 2 and is formed between the second electrode 32 and the second compound semiconductor layer 22 in the light emitting element of Example 12 or Examples 13 to 16 described later. The optical film thickness of the mode loss action site 54 can be set to a value deviating from an integral multiple of 1 / 4 of the wavelength λ 0 of the light generated in the light emitting element. Alternatively, the optical film thickness t 0can also be set to an integer multiple of 1 / 4 of the wavelength λ of the light generated in the light-emitting element. That is, the optical film thickness t 0 of the mode loss action site 54 0 can be set to a thickness that does not disturb the phase of the light generated in the light-emitting element and does not destroy the standing wave. However, it does not necessarily have to be exactly an integer multiple of 1 / 4, (λ 0 / 4n 0 )×m-(λ 0 / 8n 0 )≦t 0 ≦(λ 0 / 4n 0 )×2m+(λ 0 / 8n 0 ) (E) just needs to be satisfied. Specifically, when the optical film thickness t 0 of the mode loss action site 54 is set such that the value of 1 / 4 of the wavelength of the light generated in the light-emitting element is "100", it is preferably about 25 to 250. By adopting these configurations, the phase difference between the laser light passing through the mode loss action site 54 and the laser light passing through the current injection region 51 can be changed (the phase difference can be controlled), the control of the oscillation mode loss can be performed with a higher degree of freedom, and the design freedom of the light-emitting element can be increased.

[0186] In Example 12, the shape of the boundary between the current injection region 51 and the non-current injection / inner region 52 was circular (diameter: 8 μm), and the shape of the boundary between the non-current injection / inner region 52 and the non-current injection / outer region 53 was circular (diameter: 12 μm). That is, when the area of the orthographic image of the current injection region 51 is S 1 , and the area of the orthographic image of the non-current injection / inner region 52 is S 2 , 0.01≦S 1 / (S 1 +S 2 )≦0.7 (D-1) is satisfied. Specifically, S 1 / (S 1 +S 2 )=8 2 / 12 2 =0.44 is the case.

[0187] In Example 12 or in the light-emitting elements of Examples 13 to 14 and Example 16 described later, the optical distance from the light-emitting layer 23 in the current injection region 51 to the second surface of the second compound semiconductor layer 22 is L 2 , and the optical distance from the light-emitting layer 23 in the mode loss action region 55 to the top surface of the mode loss action site 54 (the surface facing the second electrode 32) is L 0 When this is the case, L 0 >L 2 is satisfied. Specifically, L 0 / L 2 = 1.5 was set. Then, the laser light having the generated higher-order mode is dissipated outward from the resonator structure constituted by the first light reflection layer 41 and the second light reflection layer 42 by the mode loss action region 55, whereby the oscillation mode loss increases. That is, the light field intensities of the generated fundamental mode and higher-order modes are reduced as they move away from the Z-axis within the orthographic image of the mode loss action region 55 due to the presence of the mode loss action region 55 that acts on the increase and decrease of the oscillation mode loss (see the conceptual diagram in (B) of FIG. 28). However, the reduction in the light field intensity of the higher-order mode is greater than the reduction in the light field intensity of the fundamental mode, so that the fundamental mode can be further stabilized, the threshold current can be reduced, and the relative light field intensity of the fundamental mode can be increased. Moreover, the trailing portion of the light field intensity of the higher-order mode is located further away from the current injection region than the conventional light-emitting element (see (A) of FIG. 28), so that the influence of the inverse lens effect can be reduced. Incidentally, originally, if the mode loss action site 54 made of SiO 2 is not provided, oscillation mode mixing will occur.

[0188] The first compound semiconductor layer 21 is made of an n-GaN layer, and the light-emitting layer 23 is an In 0.04 Ga 0.96 N layer (barrier layer) and an In 0.16 Ga 0.84It consists of a five - layer multiple quantum well structure in which N - layer (well layer) is laminated, and the second compound semiconductor layer 22 is composed of a p - GaN layer. Also, the first electrode 31 is composed of Ti / Pt / Au, and the second electrode 32 is composed of a transparent conductive material, specifically, ITO. A circular opening 54A is formed in the mode loss action site 54, and the second compound semiconductor layer 22 is exposed at the bottom of this opening 54A. On the edge of the first electrode 31, a pad electrode (not shown) composed of, for example, Ti / Pt / Au or V / Pt / Au for electrically connecting to an external electrode or circuit is formed or connected. On the edge of the second electrode 32, a pad electrode 33 composed of, for example, Ti / Pd / Au or Ti / Ni / Au for electrically connecting to an external electrode or circuit is formed or connected. The first light - reflecting layer 41 and the second light - reflecting layer 42 are composed of a laminated structure of a SiN layer and a SiO 2 layer (total number of dielectric film laminations: 20 layers).

[0189] In the light - emitting element of Example 12, the current non - injection inner region 52 and the current non - injection outer region 53 are formed by ion implantation into the laminated structure 20. As the ion species, for example, boron is selected, but it is not limited to boron ions.

[0190] Hereinafter, an outline of the manufacturing method of the light - emitting element of Example 12 will be described.

[0191] [Process - 1200] In manufacturing the light - emitting element of Example 12, first, the same process as [Process - 700] of Example 7 is executed.

[0192] [Process - 1210] Next, based on the ion implantation method using boron ions, the current non - injection inner region 52 and the current non - injection outer region 53 are formed in the laminated structure 20.

[0193] [Process - 1220] Thereafter, in the same process as [Process - 710] of Example 7, on the second surface 22b of the second compound semiconductor layer 22, based on a well - known method, an opening 54A is provided, and SiO 2A mode loss action site (mode loss action layer) 54 consisting of... is formed (see Fig. 27A).

[0194] [Process - 1230] Thereafter, by performing the same processes as [Process - 720] to [Process - 760] of Example 7, the light - emitting element of Example 12 can be obtained. The structure obtained during the process similar to [Process - 720] is shown in Fig. 27B.

[0195] In the light-emitting element of Example 12, a current injection region, a current non-injection / inner region surrounding the current injection region, and a current non-injection / outer region surrounding the current non-injection / inner region are formed in the stacked structure, and the orthographic image of the mode loss action region overlaps with the orthographic image of the current non-injection / outer region. That is, the current injection region and the mode loss action region are separated (isolated) by the current non-injection / inner region. Therefore, as shown in (B) of FIG. 28 in the conceptual diagram, it becomes possible to make the increase or decrease of the oscillation mode loss (specifically, an increase in Example 12) into a desired state. Alternatively, by appropriately determining the positional relationship between the current injection region and the mode loss action region, the thickness of the mode loss action site constituting the mode loss action region, etc., it becomes possible to make the increase or decrease of the oscillation mode loss into a desired state. As a result, problems in conventional light-emitting elements such as an increase in threshold current or deterioration of slope efficiency can be solved. For example, by reducing the oscillation mode loss in the fundamental mode, a decrease in threshold current can be achieved. Moreover, since the region where the oscillation mode loss is given and the region where current is injected and contributes to light emission can be controlled independently, that is, since the control of the oscillation mode loss and the control of the light emission state of the light-emitting element can be performed independently, the degree of freedom of control and the degree of freedom of design of the light-emitting element can be increased. Specifically, by setting the current injection region, the current non-injection region, and the mode loss action region in the above-described predetermined positional relationship, the magnitude relationship of the oscillation mode loss given by the mode loss action region to the fundamental mode and higher-order modes can be controlled, and by making the oscillation mode loss given to the higher-order modes relatively larger than the oscillation mode loss given to the fundamental mode, the fundamental mode can be further stabilized. Moreover, since the light-emitting element of Example 12 has the concave mirror portion 43, the occurrence of diffraction loss can be more reliably suppressed.

Example

[0196] Example 13 is a modification of Example 12 and relates to a light-emitting element having a 2-B configuration. As shown in the schematic partial cross-sectional view of FIG. 29, in the light-emitting element of Example 13, the current non-injection inner region 52 and the current non-injection outer region 53 are formed by plasma irradiation of the second surface of the second compound semiconductor layer 22, or ashing treatment of the second surface of the second compound semiconductor layer 22, or reactive ion etching (RIE) treatment of the second surface of the second compound semiconductor layer 22. And since the current non-injection inner region 52 and the current non-injection outer region 53 are thus exposed to plasma particles (specifically, argon, oxygen, nitrogen, etc.), the conductivity of the second compound semiconductor layer 22 deteriorates, and the current non-injection inner region 52 and the current non-injection outer region 53 become in a high-resistance state. That is, the current non-injection inner region 52 and the current non-injection outer region 53 are formed by exposure of the second surface 22b of the second compound semiconductor layer 22 to plasma particles. In FIGS. 29, 30, 31, and 32, illustration of the first light reflection layer 41 and the film thickness modulation layer 80 is omitted.

[0197] Also in Example 13, the shape of the boundary between the current injection region 51 and the current non-injection inner region 52 was made circular (diameter: 10 μm), and the shape of the boundary between the current non-injection inner region 52 and the current non-injection outer region 53 was made circular (diameter: 15 μm). That is, when the area of the orthographic image of the current injection region 51 is S 1 and the area of the orthographic image of the current non-injection inner region 52 is S 2 , then 0.01 ≦ S 1 / (S 1 + S 2 ) ≦ 0.7 (D-1) is satisfied. Specifically, S 1 / (S 1 + S 2 ) = 10 2 / 15 2 = 0.44 is.

[0198] In Example 13, instead of [Process - 1210] of Example 12, based on plasma irradiation on the second surface of the second compound semiconductor layer 22, or ashing treatment on the second surface of the second compound semiconductor layer 22, or reactive ion etching treatment on the second surface of the second compound semiconductor layer 22, the current non - injection inner region 52 and the current non - injection outer region 53 may be formed in the stacked structure 20.

[0199] Except for the above points, the configuration and structure of the light - emitting element of Example 13 can be the same as those of the light - emitting element of Example 12, so detailed description is omitted.

[0200] Even in the light - emitting element of Example 13 or Example 14 described later, by setting the current injection region, the current non - injection region, and the mode loss action region in the predetermined arrangement relationship described above, the magnitude relationship of the oscillation mode loss given by the mode loss action region to the fundamental mode and higher - order modes can be controlled. By making the oscillation mode loss given to the higher - order mode relatively larger than the oscillation mode loss given to the fundamental mode, the fundamental mode can be further stabilized.

Example

[0201] Example 14 is a modification of Examples 12 to 13 and relates to a light - emitting element of the second - C configuration. As shown in the schematic partial cross - sectional view of FIG. 30, in the light - emitting element of Example 14, the second light - reflecting layer 42 has a region that reflects or scatters the light from the first light - reflecting layer 41 toward the outside of the resonator structure composed of the first light - reflecting layer 41 and the second light - reflecting layer 42 (i.e., toward the mode loss action region 55). Specifically, the portion of the second light - reflecting layer 42 located above the side wall of the mode loss action site (mode loss action layer) 54 (the side wall of the opening 54B) has a forward - tapered inclined portion 42A, or alternatively, has a region that is convexly curved toward the first light - reflecting layer 41.

[0202] In Example 14, the shape of the boundary between the current injection region 51 and the non-current injection / inner region 52 was circular (diameter: 8 μm), and the shape of the boundary between the non-current injection / inner region 52 and the non-current injection / outer region 53 was circular (diameter: 10 μm to 20 μm).

[0203] In Example 14, in the same process as [Process - 1220] of Example 12, when forming the mode loss action site (mode loss action layer) 54 composed of SiO 2 it is only necessary to form the opening 54B having a tapered side wall. Specifically, a resist layer is formed on the mode loss action layer formed on the second surface 22b of the second compound semiconductor layer 22, and an opening is provided in the portion of the resist layer where the opening 54B is to be formed based on photolithography technology. Based on a well-known method, the side wall of this opening is made tapered. Then, by performing etch-back, an opening 54B having a tapered side wall can be formed in the mode loss action site (mode loss action layer) 54. Furthermore, by forming the second electrode 32 and the second light reflection layer 42 on such a mode loss action site (mode loss action layer) 54, a tapered inclined portion 42A can be imparted to the second light reflection layer 42.

[0204] Except for the above points, the configuration and structure of the light-emitting element of Example 14 can be the same as those of the light-emitting elements of Examples 12 to 13, so detailed description is omitted.

Example

[0205] Example 15 is a modification of Examples 12 to 14 and relates to a light-emitting element having a second-D configuration. As shown in a schematic partial cross-sectional view of the light-emitting element of Example 15 in Fig. 31 and a schematic partial cross-sectional view of the main part cut out in Fig. 32, a convex portion 22A is formed on the second surface 22b side of the second compound semiconductor layer 22. Then, as shown in Figs. 31 and 32, the mode loss action site (mode loss action layer) 54 is formed on the region 22B of the second surface 22b of the second compound semiconductor layer 22 surrounding the convex portion 22A. The convex portion 22A occupies the current injection region 51, the current injection region 51, and the current non-injection / inner region 52. The mode loss action site (mode loss action layer) 54 is made of a dielectric material such as SiO 2 as in Example 12. A current non-injection / outer region 53 is provided in the region 22B. Let the optical distance from the light-emitting layer 23 to the second surface of the second compound semiconductor layer 22 in the current injection region 51 be L 2 , and the optical distance from the light-emitting layer 23 to the top surface (the surface facing the second electrode 32) of the mode loss action site 54 in the mode loss action region 55 be L 0 . When this is done, L 0 < L 2 is satisfied. Specifically, L 2 / L 0 = 1.5 is set. Thereby, a lens effect is generated in the light-emitting element.

[0206] In the light-emitting element of Example 15, the laser light having the generated higher-order mode is confined to the current injection region 51 and the current non-injection / inner region 52 by the mode loss action region 55, whereby the oscillation mode loss is reduced. That is, the light field intensities of the generated fundamental mode and higher-order mode increase within the orthographic image of the current injection region 51 and the current non-injection / inner region 52 due to the presence of the mode loss action region 55 that acts on the increase and decrease of the oscillation mode loss.

[0207] In Example 15, the shape of the boundary between the current injection region 51 and the non-current injection / inner region 52 was circular (diameter: 8 μm), and the shape of the boundary between the non-current injection / inner region 52 and the non-current injection / outer region 53 was circular (diameter: 30 μm).

[0208] In Example 15, between [Process - 1210] and [Process - 1220] of Example 12, a convex portion 22A may be formed by removing a part of the second compound semiconductor layer 22 from the second surface 22b side.

[0209] Except for the above points, the configuration and structure of the light-emitting element of Example 15 can be the same as those of the light-emitting element of Example 12, so a detailed description will be omitted. In the light-emitting element of Example 15, not only can the oscillation mode loss provided by the mode loss action region be suppressed for various modes, the transverse mode be multi-mode oscillated, but also the threshold value of laser oscillation can be reduced. Further, as shown in (C) of FIG. 28 in the conceptual diagram, the optical field intensities of the generated fundamental mode and higher-order modes can be increased within the orthographic images of the current injection region and the non-current injection / inner region due to the presence of the mode loss action region that acts on the increase and decrease (specifically, decrease in Example 15) of the oscillation mode loss.

Example

[0210] Example 16 is a modification of Examples 12 to 15. More specifically, the light-emitting element of Example 16 or Example 17 to be described later is a surface-emitting laser element (light-emitting element) (vertical cavity surface-emitting laser, VCSEL) that emits laser light from the top surface of the first compound semiconductor layer 21 through the film thickness modulation layer 80 and the first light reflection layer 41.

[0211] In the light-emitting element of Example 16, as shown in the schematic partial cross-sectional view of FIG. 33, the second light reflection layer 42 is fixed to a support substrate 49 composed of a silicon semiconductor substrate by a soldering method via a bonding layer 48 composed of a gold (Au) layer or a solder layer containing tin (Sn). In the manufacture of the light-emitting element of Example 16, except for the removal of the support substrate 49, that is, without removing the support substrate 49, for example, the same steps as [Process - 1200] to [Process - 1230] of Example 12 may be executed.

[0212] Also in the light-emitting element of Example 16, by setting the current injection region, current non-injection region, and mode loss action region in the predetermined arrangement relationship described above, it is possible to control the magnitude relationship of the oscillation mode loss provided by the mode loss action region for the fundamental mode and higher-order modes, and by making the oscillation mode loss provided to the higher-order mode relatively larger than the oscillation mode loss provided to the fundamental mode, the fundamental mode can be further stabilized.

[0213] In the example of the light-emitting element described above and shown in FIG. 33, the end of the first electrode 31 is separated from the first light reflection layer 41. That is, the first light reflection layer 41 and the first electrode 31 are separated, in other words, they have an offset, and the separation distance is within 1 mm, specifically, for example, an average of 0.05 mm. However, it is not limited to such a structure, and the end of the first electrode 31 may be in contact with the first light reflection layer 41, or the end of the first electrode 31 may extend over the edge of the first light reflection layer 41.

[0214] Also, for example, after performing the same steps as [Step - 1200] to [Step - 1230] of Example 12, the substrate 11 for manufacturing the light - emitting element is removed to expose the first surface 21a of the first compound semiconductor layer 21. Then, a film - thickness modulation layer 80, a first light - reflecting layer 41, and a first electrode 31 may be formed on the first surface 21a of the first compound semiconductor layer 21. Also, when forming the film - thickness modulation layer 80 and the first light - reflecting layer 41 on the first surface 21a of the first compound semiconductor layer 21, the first compound semiconductor layer 21 may be etched to form a recess on the first surface 21a of the first compound semiconductor layer 21, and the film - thickness modulation layer 80 and the first light - reflecting layer 41 may be formed in this recess. And in this case, if the side wall of the recess is made into a tapered shape in sequence, a light - emitting element with a second - C configuration can be obtained. That is, the first light - reflecting layer 41 has a region (slanting portion) that reflects or scatters the light from the second light - reflecting layer 42 toward the outside of the resonator structure composed of the first light - reflecting layer 41 and the second light - reflecting layer 42.

Example

[0215] Example 17 is a modification of Examples 7 to 11 and relates to a light - emitting element with a third configuration, specifically, a light - emitting element with a third - A configuration. More specifically, the light - emitting element of Example 17 is a surface - emitting laser element (light - emitting element) (vertical - cavity surface - emitting laser, VCSEL) that emits laser light from the top surface of the first compound semiconductor layer 21 through the film - thickness modulation layer 80 and the first light - reflecting layer 41.

[0216] The light - emitting element of Example 17, a schematic partial end - face view of which is shown in Fig. 34, (a) A first compound semiconductor layer 21 made of a GaN - based compound semiconductor, having a first surface 21a and a second surface 21b opposite to the first surface 21a, A light - emitting layer (active layer) 23 made of a GaN - based compound semiconductor and in contact with the second surface 21b of the first compound semiconductor layer 21, and A second compound semiconductor layer 22 made of a GaN - based compound semiconductor, having a first surface 22a and a second surface 22b opposite to the first surface 22a, and the first surface 22a being in contact with the light - emitting layer 23, are laminated to form a laminated structure 20, (b) A second electrode 32 formed on the second surface 22b of the second compound semiconductor layer 22, (c) a second light reflection layer 42 formed on the second electrode 32, (d) a mode loss acting site 64 provided on the first surface 21a of the first compound semiconductor layer 21 and constituting a mode loss acting region 65 that acts on the increase and decrease of oscillation mode loss, (e) a film thickness modulation layer 80 and a first light reflection layer 41 formed from above the first surface 21a of the first compound semiconductor layer 21 across the mode loss acting site 64, and (f) a first electrode 31 electrically connected to the first compound semiconductor layer 21, and is provided with. In the light emitting element of Example 17, the first electrode 31 is formed on the first surface 21a of the first compound semiconductor layer 21.

[0217] And in the stacked structure 20, a current injection region 61, a current non-injection inner region 62 surrounding the current injection region 61, and a current non-injection outer region 63 surrounding the current non-injection inner region 62 are formed, and the orthographic image of the mode loss acting region 65 and the orthographic image of the current non-injection outer region 63 overlap. Here, although current non-injection regions 62 and 63 are formed in the stacked structure 20, in the illustrated example, they are formed across a part of the first compound semiconductor layer 21 from the second compound semiconductor layer 22 in the thickness direction. However, the current non-injection regions 62 and 63 may be formed in the region on the second electrode side of the second compound semiconductor layer 22 in the thickness direction, may be formed in the entire second compound semiconductor layer 22, or may be formed in the second compound semiconductor layer 22 and the light emitting layer 23.

[0218] The configurations of the stacked structure 20, the pad electrode 33, the film thickness modulation layer 80, the first light reflection layer 41, and the second light reflection layer 42 can be the same as those in Example 12, and the configurations of the bonding layer 48 and the support substrate 49 can be the same as those in Example 16. A circular opening 64A is formed in the mode loss acting site 64, and the first surface 21a of the first compound semiconductor layer 21 is exposed at the bottom of this opening 64A.

[0219] The mode loss acting site (mode loss acting layer) 64 is SiO 2It is made of a dielectric material such as this and is formed on the first surface 21a of the first compound semiconductor layer 21. The optical film thickness t of the mode loss action site 64 0 can be a value that deviates from an integer multiple of 1 / 4 of the wavelength λ of the light generated in the light emitting element. Alternatively, the optical film thickness t of the mode loss action site 64 0 can also be an integer multiple of 1 / 4 of the wavelength λ of the light generated in the light emitting element. That is, the optical film thickness t of the mode loss action site 64 0 can be a thickness that does not disturb the phase of the light generated in the light emitting element and does not destroy the standing wave. However, it does not necessarily have to be exactly an integer multiple of 1 / 4, 0 and it is sufficient to satisfy (λ 0 / 4n )×m-(λ 0 / 4n 0 )×m-(λ 0 / 8n 0 )≦t 0 ≦(λ 0 / 4n 0 )×2m+(λ 0 / 8n 0 ) (E) . Specifically, when the value of 1 / 4 of the wavelength λ of the light generated in the light emitting element is set to "100", the optical film thickness t of the mode loss action site 64 0 is preferably about 25 to 250. By adopting these configurations, the phase difference between the laser light passing through the mode loss action site 64 and the laser light passing through the current injection region 61 can be changed (the phase difference can be controlled), the control of the oscillation mode loss can be performed with a higher degree of freedom, and the design freedom of the light emitting element can be increased further. 0

[0220] In Example 17, the shape of the boundary between the current injection region 61 and the non-current injection / inner region 62 was circular (diameter: 8 μm), and the shape of the boundary between the non-current injection / inner region 62 and the non-current injection / outer region 63 was circular (diameter: 15 μm). That is, when the area of the orthographic image of the current injection region 61 is S 1 ' and the area of the orthographic image of the non-current injection / inner region 62 is S 2 ', 0.01≦S 1 ​’ / (S 1 ’+S 2 ’) ≦ 0.7 (D - 2) is satisfied. Specifically, S 1 ’ / (S 1 ’+S 2 ’)=8 2 / 15 2 =0.28 is the case.

[0221] In the light-emitting element of Example 17, the optical distance from the light-emitting layer 23 in the current injection region 61 to the first surface of the first compound semiconductor layer 21 is L 1 ’, and the optical distance from the light-emitting layer 23 in the mode loss action region 65 to the top surface of the mode loss action site 64 (the surface facing the first electrode 31) is L 0 ’. When L 0 ’>L 1 ’ is satisfied. Specifically, L 0 ’ / L 1 ’=1.01 is set. Then, the laser light having the generated higher-order mode is dissipated outward by the mode loss action region 65 toward the resonator structure composed of the first light reflection layer 41 and the second light reflection layer 42, whereby the oscillation mode loss increases. That is, the light field intensities of the generated fundamental mode and higher-order mode are decreased as they are farther from the Z-axis within the orthographic image of the mode loss action region 65 due to the presence of the mode loss action region 65 that acts on the increase and decrease of the oscillation mode loss (see the conceptual diagram in (B) of FIG. 28), but the decrease in the light field intensity of the higher-order mode is greater than the decrease in the light field intensity of the fundamental mode, so that the fundamental mode can be further stabilized, the threshold current can be reduced, and the relative light field intensity of the fundamental mode can be increased.

[0222] In the light-emitting element of Example 17, the current non-injection inner region 62 and the current non-injection outer region 63 are formed by ion implantation into the laminated structure 20 in the same manner as in Example 12. As the ion species, for example, boron is selected, but it is not limited to boron ions.

[0223] Hereinafter, a method for manufacturing a light-emitting element of Example 17 will be described.

[0224] [Step - 1700] First, by performing the same steps as [Step - 1200] of Example 12, a laminate structure 20 can be obtained. Next, by performing the same steps as [Step - 1210] of Example 12, a current non-injection inner region 62 and a current non-injection outer region 63 can be formed in the laminate structure 20.

[0225] [Step - 1710] Next, a second electrode 32 is formed on the second surface 22b of the second compound semiconductor layer 22, for example, by a lift-off method, and a pad electrode 33 is further formed based on a well-known method. Then, a second light reflection layer 42 is formed from above the second electrode 32 to above the pad electrode 33 based on a well-known method.

[0226] [Step - 1720] Thereafter, the second light reflection layer 42 is fixed to the support substrate 49 via the bonding layer 48.

[0227] [Step - 1730] Next, the substrate 11 for manufacturing the light-emitting element is removed to expose the first surface 21a of the first compound semiconductor layer 21. Specifically, first, the thickness of the substrate 11 for manufacturing the light-emitting element is reduced based on a mechanical polishing method, and then the remaining portion of the substrate 11 for manufacturing the light-emitting element is removed based on a CMP method. Thus, the first surface 21a of the first compound semiconductor layer 21 is exposed.

[0228] [Step - 1740] Thereafter, on the first surface 21a of the first compound semiconductor layer 21, a mode loss action site (mode loss action layer) 64 having an opening 64A and made of SiO 2 is formed based on a well-known method.

[0229] [Step - 1750] Next, a thickness modulation layer 80 and a first light reflection layer 41, which are composed of a concave mirror portion 43 formed by a base portion 45F, a thickness modulation layer 80, and a multilayer light reflection film 46, are formed on a first surface 21a of a first compound semiconductor layer 21 exposed at the bottom of an opening 64A of a mode loss action portion 64. Further, a first electrode 31 is formed. Thus, a light-emitting element of Example 17 having the structure shown in FIG. 34 can be obtained.

[0230] [Process - 1760] Thereafter, the light-emitting element is separated by performing so-called element isolation, and the side surface and exposed surface of the stacked structure are coated with an insulating film made of, for example, SiO 2 . Then, by packaging and sealing, the light-emitting element of Example 17 is completed.

[0231] Even in the light-emitting element of Example 17, a current injection region, a current non-injection / inner region surrounding the current injection region, and a current non-injection / outer region surrounding the current non-injection / inner region are formed in the stacked structure, and the orthographic image of the mode loss action region and the orthographic image of the current non-injection / outer region overlap. Therefore, as shown in FIG. 28(B) of the conceptual diagram, it is possible to make the increase and decrease of the oscillation mode loss (specifically, an increase in Example 17) into a desired state. Moreover, since the control of the oscillation mode loss and the control of the light-emitting state of the light-emitting element can be performed independently, the degree of freedom of control and the degree of freedom of design of the light-emitting element can be increased. Specifically, by setting the current injection region, the current non-injection region, and the mode loss action region in the above-described predetermined positional relationship, the magnitude relationship of the oscillation mode loss given by the mode loss action region to the fundamental mode and higher-order modes can be controlled, and by making the oscillation mode loss given to the higher-order modes relatively larger than the oscillation mode loss given to the fundamental mode, the fundamental mode can be further stabilized. Also, it is possible to reduce the influence of the reverse lens effect. Moreover, since the light-emitting element of Example 17 has the concave mirror portion 43, the occurrence of diffraction loss can be more reliably suppressed.

[0232] Even in Example 17, similar to Example 13, the current non-injection inner region 62 and the current non-injection outer region 63 can be formed by plasma irradiation on the second surface of the second compound semiconductor layer 22, or ashing treatment on the second surface of the second compound semiconductor layer 22, or reactive ion etching (RIE) treatment on the second surface of the second compound semiconductor layer 22 (light-emitting element of the 3-B configuration). By thus exposing the current non-injection inner region 62 and the current non-injection outer region 63 to plasma particles, the conductivity of the second compound semiconductor layer 22 deteriorates, and the current non-injection inner region 62 and the current non-injection outer region 63 become in a high-resistance state. That is, the current non-injection inner region 62 and the current non-injection outer region 63 are formed by exposure of the second surface 22b of the second compound semiconductor layer 22 to plasma particles.

[0233] Also, similar to Example 14, the second light reflection layer 42 can be configured to have a region that reflects or scatters the light from the first light reflection layer 41 toward the outside of the resonator structure constituted by the first light reflection layer 41 and the second light reflection layer 42 (i.e., toward the mode loss action region 65) (light-emitting element of the 3-C configuration). Alternatively, similar to Example 16, when forming the film thickness modulation layer 80 and the first light reflection layer 41 on the first surface 21a of the first compound semiconductor layer 21, the first compound semiconductor layer 21 is etched to form a recess in the first surface 21a of the first compound semiconductor layer 21, and the film thickness modulation layer 80 and the first light reflection layer 41 are formed in this recess, but the side wall of the recess may be in a tapered shape.

[0234] Also, similar to Example 15, a convex portion may be formed on the first surface 21a side of the first compound semiconductor layer 21, and the mode loss action site (mode loss action layer) 64 may be formed on the region of the first surface 21a of the first compound semiconductor layer 21 surrounding the convex portion (light-emitting device of the third-D configuration). The mode loss action site (mode loss action layer) 64 may be formed on the region of the first surface 21a of the first compound semiconductor layer 21 surrounding the convex portion. The convex portion occupies the current injection region 61, the current injection region 61, and the non-current injection / inner region 62. And thereby, the laser light having the generated higher-order mode is confined in the current injection region 61 and the non-current injection / inner region 62 by the mode loss action region 65, and thus, the oscillation mode loss is reduced. That is, the light field intensities of the generated fundamental mode and higher-order mode increase within the orthographic projection images of the current injection region 61 and the non-current injection / inner region 62 due to the presence of the mode loss action region 65 that acts on the increase and decrease of the oscillation mode loss. Even in the modified example of the light-emitting device of Example 17 having such a configuration, not only can the oscillation mode loss provided by the mode loss action region 65 for various modes be suppressed and the transverse mode be made to oscillate in multiple modes, but also the threshold value of laser oscillation can be reduced. Further, as shown in (C) of FIG. 28 in the conceptual diagram, the light field intensities of the generated fundamental mode and higher-order mode can be increased within the orthographic projection images of the current injection region and the non-current injection / inner region due to the presence of the mode loss action region 65 that acts on the increase and decrease (specifically, decrease in the modified example of the light-emitting device of Example 17) of the oscillation mode loss.

[0235] In some cases, a convex portion (mesa structure) may be formed on the first surface 21a side of the first compound semiconductor layer 21, and the region of the first compound semiconductor layer 21 surrounding the convex portion may be used as a mode loss action region (mode loss action site). That is, in this case, the formation of the mode loss action layer may be omitted, and the mode loss action site may be constituted by the region of the first compound semiconductor layer surrounding the convex portion. Then, the film thickness modulation layer 80 and the first light reflection layer 41 may be formed on the top surface of the convex portion. The convex portion occupies the current injection region 61, the current injection region 61, and the current non-injection / inner region 62. And thereby, the laser light having the generated higher-order mode is confined in the current injection region 61 and the current non-injection / inner region 62 by the mode loss action region, so that the oscillation mode loss is reduced. That is, the light field intensities of the generated fundamental mode and higher-order modes increase within the orthographic images of the current injection region 61 and the current non-injection / inner region 62 due to the presence of the mode loss action region that acts on the increase and decrease of the oscillation mode loss. Even in a modified example of the light-emitting element of Example 17 having such a configuration, not only can the oscillation mode loss provided by the mode loss action region for various modes be suppressed and the lateral mode be made to oscillate in multiple modes, but also the threshold value of laser oscillation can be reduced. Also, as shown in (C) of FIG. 28 in the conceptual diagram, the light field intensities of the generated fundamental mode and higher-order modes can be increased within the orthographic images of the current injection region and the current non-injection / inner region due to the presence of the mode loss action region that acts on the increase and decrease (specifically, decrease in the modified example of the light-emitting element of Example 17) of the oscillation mode loss.

Example

[0236] Example 18 is a modification of Examples 7 to 17, and further a modification of Example 4, and relates to a light-emitting element of the fourth configuration.

[0237] As shown in the partial cross-sectional view of the mode in FIG. 35, in the light-emitting element of Example 18, similar to Example 4, in the laminated structure 20 including the second electrode 32, at least two light absorption material layers 91, preferably at least four light absorption material layers 91, and specifically, in Example 18, 20 light absorption material layers 91 are formed in parallel with the virtual plane occupied by the light-emitting layer 23. For simplicity of the drawing, only two light absorption material layers 91 are shown in the drawing.

[0238] Also in Example 18, the oscillation wavelength (the desired oscillation wavelength emitted from the light-emitting element) λ 0 is 450 nm. The 20 light absorption material layers 91 are made of a compound semiconductor material having a narrower bandgap than the compound semiconductor constituting the laminated structure 20. Specifically, n-In 0.2 Ga 0.8 N and are formed inside the first compound semiconductor layer 21. The thickness of the light absorption material layer 91 is λ 0 / (4·n eq ) or less, specifically 3 nm. Also, the light absorption coefficient of the light absorption material layer 91 is at least twice the light absorption coefficient of the first compound semiconductor layer 21 made of an n-GaN layer, specifically, 1×10 3 times.

[0239] Also, the light absorption material layer 91 is located at the lowest amplitude portion generated in the standing wave of light formed inside the laminated structure, and the light-emitting layer 23 is located at the maximum amplitude portion generated in the standing wave of light formed inside the laminated structure. The distance between the center in the thickness direction of the light-emitting layer 23 and the center in the thickness direction of the light absorption material layer 91 adjacent to the light-emitting layer 23 is 46.5 nm. Further, the equivalent refractive index of the entire part of the laminated structure (specifically, in Example 18, the first compound semiconductor layer 21) located between the two light absorption material layers 91 and between the light absorption material layers 91 is n eq , and the distance between the light absorption material layers 91 is L AbsWhen this is the case, the above-described formula (B-1) [where m = 1] is satisfied. Therefore, the distance between adjacent light absorption material layers 91 satisfies the above-described formula (B-2) in all of the plurality of light absorption material layers 91 (20 light absorption material layers 91). The value of the equivalent refractive index n eq is specifically 2.42, and when m = 1, specifically, L Abs = 1×450 / (2×2.42) = 93.0 nm That is. Among the 20 light absorption material layers 91, for some of the light absorption material layers 91, m can also be any integer of 2 or more.

[0240] In the manufacture of the light-emitting element of Example 18, in the same process as [Process - 700] of Example 7, the laminated structure 20 is formed. At this time, 20 light absorption material layers 91 are also formed inside the first compound semiconductor layer 21. Except for this point, the light-emitting element of Example 18 can be manufactured based on the same method as the light-emitting element of Example 7.

[0241] When a plurality of longitudinal modes are generated within the gain spectrum determined by the light-emitting layer 23, schematically representing this is as shown in FIG. 11 described above. And in this case, it is assumed that the light absorption material layer 91 is located at the lowest amplitude portion of the longitudinal mode A and is not located at the lowest amplitude portion of the longitudinal mode B. Then, the mode loss of the longitudinal mode A is minimized, but the mode loss of the longitudinal mode B is large. Therefore, the longitudinal mode A is more likely to oscillate than the longitudinal mode B. Therefore, by using such a structure, that is, by controlling the position and period of the light absorption material layer 91, a specific longitudinal mode can be stabilized and made more likely to oscillate. On the other hand, since the mode loss for other unwanted longitudinal modes can be increased, it is possible to suppress the oscillation of other unwanted longitudinal modes.

[0242] As described above, in the light-emitting element of Example 18, since at least two light absorption material layers are formed inside the laminated structure, among the plurality of types of longitudinal mode laser lights that can be emitted from the surface-emitting laser element, oscillation of the undesired longitudinal mode laser light can be suppressed. As a result, it becomes possible to accurately control the oscillation wavelength of the emitted laser light. Moreover, since the light-emitting element of Example 18 has the concave mirror portion 43, generation of diffraction loss can be surely suppressed.

[0243] In the light-emitting element of Example 18, in the same manner as described in Example 5, the light absorption material layer 91 can be composed of a compound semiconductor material doped with impurities, specifically, a compound semiconductor material having an impurity concentration (impurity: Si) of 1×10 19 / cm 3 (specifically, n-GaN:Si).

[0244] Also, in the same manner as described in Example 6, the five light absorption material layers can be composed of n-In 0.3 Ga 0.7 N, and one light absorption material layer (also serving as the second electrode 32 made of ITO) can be composed of a transparent conductive material. The five light absorption material layers satisfy the above-described formula (B-2), and also satisfy the above-described formula (B-3). Note that the positional relationship between the light absorption material layer also serving as the second electrode 32 and the light absorption material layer 91 satisfies the above-described formula (B-1).

[0245] Also, as a modified example of the light-emitting element of Example 18, it can be configured to emit laser light from the top surface of the first compound semiconductor layer 21 through the first light reflection layer 41. That is, as shown in a schematic partial cross-sectional view in FIG. 36, the second light reflection layer 42 is fixed to a support substrate 49 made of a silicon semiconductor substrate by a soldering method via a bonding layer 48 made of a gold (Au) layer or a solder layer containing tin (Sn). Such a light-emitting element can be manufactured in the same manner as the light-emitting element of Example 7, except that 20 light absorption material layers 91 are also formed inside the first compound semiconductor layer 21 and except that the support substrate 49 is not removed.

[0246] As described above, the light-emitting element of the present disclosure has been described based on various preferred embodiments. However, the light-emitting element of the present disclosure is not limited to these embodiments. The configuration and structure of the light-emitting element described in the embodiments are illustrative and can be changed as appropriate. Also, the manufacturing method of the light-emitting element can be changed as appropriate. In some cases, by appropriately selecting the bonding layer and the support substrate, a surface-emitting laser element that emits light from the top surface of the second compound semiconductor layer through the second light reflection layer can be obtained. After forming the first light reflection layer and the first electrode, by removing the support substrate, a surface-emitting laser element that emits light from the top surface of the second compound semiconductor layer through the second light reflection layer can be completed. Alternatively, the first light reflection layer can be fixed to a second support substrate, and then the support substrate can be removed to expose the second light reflection layer, thereby completing a surface-emitting laser element that emits light from the top surface of the second compound semiconductor layer through the second light reflection layer.

[0247] In addition, the present disclosure can also have the following configuration. [A01] 《Light-Emitting Element》 It is formed by laminating a first light reflection layer, a laminated structure, and a second light reflection layer. The laminated structure is formed by laminating a first compound semiconductor layer, a light-emitting layer, and a second compound semiconductor layer from the first light reflection layer side. The light from the laminated structure is emitted to the outside through the first light reflection layer or the second light reflection layer. The first light reflection layer has a structure in which a plurality of at least two types of thin films are alternately laminated. A light-emitting element in which a film thickness modulation layer is provided between the laminated structure and the first light reflection layer. [A02] The first light reflection layer has a first thin film with an optical film thickness t 1 and a second thin film with an optical film thickness t 2 (However, t 2 ≠t 1 ) and has a structure in which a plurality of them are alternately laminated. The film thickness modulation layer has at least one layer with an optical film thickness t 3 (However, t 3 ≠t 1The light-emitting device according to [A01], which is composed of a third thin film having [A03]t 3 / t 1 ≧1.1, or t 3 / t 1 ≦0.9, and satisfies the requirements of [A02]. [A04]The first thin film is made of a first material, The second thin film is made of a second material different from the first material, and is the light-emitting device according to [A02] or [A03]. [A05]The film thickness modulation layer has a structure in which a third thin film and a fourth thin film having an optical film thickness t 4 are laminated, and is the light-emitting device according to any one of [A02] to [A04]. [A06]The film thickness modulation layer has a structure in which a plurality of third thin films and fourth thin films are alternately laminated, Among the third thin films, the optical film thickness of at least one layer is t 3 ≠t 1 and satisfies the requirements of [A05]. [A07]Among the fourth thin films, the optical film thickness of at least one layer is t 4 ≠t 2 and satisfies the requirements of [A06]. [A08]The third thin film that satisfies t 3 ≠t 1 or the fourth thin film that satisfies t 4 ≠t 2 is in contact with the first light reflection layer, and is the light-emitting device according to [A07]. [A09]The third thin films other than the third thin film that satisfies t 3 ≠t 1 satisfy t 3 =t 1 and t 4 ≠t 2 The fourth thin films other than the fourth thin film that satisfies t 4 =t 2 satisfy the requirements of [A08]. [A10]The total number of layers of the third thin film and the fourth thin film is 5 or less, and is the light-emitting device according to any one of [A06] to [A09]. [A11]The third thin film is made of a first material, The fourth thin film is made of a second material. The light-emitting element according to any one of [A05] to [A10]. [A12]The first light reflection layer is formed on the substrate. The light-emitting element according to any one of [A01] to [A11]. [A13]A stacked structure is formed on a region of the substrate where the first light reflection layer is not formed. The light-emitting element according to [A12]. [A14]The first light reflection layer is formed on the exposed surface of the stacked structure. The light-emitting element according to any one of [A01] to [A11]. [A15]The first material is made of a compound semiconductor material, and the second material is also made of a compound semiconductor material. The light-emitting element according to any one of [A04] to [A11]. [A16]The first material is made of a dielectric material, and the second material is also made of a dielectric material. The light-emitting element according to any one of [A04] to [A14]. [A17]The first light reflection layer has a concave mirror portion, The second light reflection layer has a flat shape. The light-emitting element according to any one of [A01] to [A16]. [A18]The thickness of the first compound semiconductor layer is thicker than the thickness of the second compound semiconductor layer. The light-emitting element according to any one of [A01] to [A17]. [A19]The stacked structure is made of a GaN-based compound semiconductor. The light-emitting element according to any one of [A01] to [A18]. [A20]Unevenness is formed at the interface between the stacked structure and the film thickness modulation layer, and the root mean square roughness Rq of the surface of the unevenness is Rq ≧ 1 nm. The light-emitting element according to any one of [A01] to [A19]. [A21]Point defects are formed at the interface between the stacked structure and the film thickness modulation layer, and the density of the point defects is 1×10 17 / cm 3 or more. The light-emitting element according to any one of [A01] to [A20]. [A22]Void spaces are formed at the interface between the stacked structure and the film thickness modulation layer, and the thickness of the void spaces is 10 nm or less. The light-emitting element according to any one of [A01] to [A21]. The material constituting the film thickness modulation layer is different from the materials constituting the first compound semiconductor layer, the light emitting layer, and the second compound semiconductor layer. The light emitting device according to any one of [A01] to [A22]. [B01]《Light Emitting Device with Light Absorbing Material Layer》 Inside the laminated structure, at least two light absorbing material layers are formed in parallel with the virtual plane occupied by the light emitting layer. The light emitting device according to any one of [A01] to [A23]. [B02]The light emitting device according to [B01], in which at least four light absorbing material layers are formed. [B03]The oscillation wavelength is λ 0 , the equivalent refractive index of the entire part of the laminated structure located between the two light absorbing material layers and between the light absorbing material layers is n eq , the distance between the light absorbing material layers is L Abs When, 0.9×{(m·λ 0 ) / (2·n eq )}≦L Abs ≦1.1×{(m·λ 0 ) / (2·n eq )} The light emitting device according to [B01] or [B02] that satisfies. However, m is 1 or any integer of 2 or more including 1. [B04]The thickness of the light absorbing material layer is λ 0 / (4·n eq ) or less. The light emitting device according to any one of [B01] to [B03]. [B05]The light emitting device according to any one of [B01] to [B04], in which the light absorbing material layer is located at the lowest amplitude part generated in the standing wave of light formed inside the laminated structure. [B06]The light emitting device according to any one of [B01] to [B05], in which the light emitting layer is located at the maximum amplitude part generated in the standing wave of light formed inside the laminated structure. [B07]The light absorbing material layer has a light absorption coefficient that is 2 times or more the light absorption coefficient of the compound semiconductor constituting the laminated structure. The light emitting device according to any one of [B01] to [B06]. [B08]The light absorption material layer is composed of at least one material selected from the group consisting of a compound semiconductor material having a narrower band gap than the compound semiconductor constituting the laminated structure, a compound semiconductor material doped with impurities, a transparent conductive material, and a light reflection layer constituent material having light absorption characteristics, and is the light-emitting element according to any one of [B01] to [B07]. [C01]《Light-emitting element having a concave mirror portion》 The first light reflection layer and the film thickness modulation layer have a concave mirror portion. The second light reflection layer has a flat shape and is the light-emitting element according to any one of [A01] to [B08]. [C02]When the resonator length is L OR and 1×10 -5 m≦L OR is satisfied, it is the light-emitting element according to [C01]. [C03]When the first light reflection layer and the film thickness modulation layer are cut in a virtual plane including the lamination direction of the laminated structure, the figure drawn by the interface facing a part of the laminated structure of the concave mirror portion composed of the first light reflection layer and the film thickness modulation layer is a part of a circle or a part of a parabola, and is the light-emitting element according to [C01] or [C02]. [D01]《Light-emitting element of the first configuration》 In the second compound semiconductor layer, a current injection region and a current non-injection region surrounding the current injection region are provided. The shortest distance D from the area centroid point of the current injection region to the boundary between the current injection region and the current non-injection region CI satisfies the following formula and is the light-emitting element according to any one of [C01] to [C03]. D CI ≧ω 0 / 2 However, ω 0 2 ≡(λ 0 / π){L OR (R DBR -L OR )} 1 / 2 Here, λ 0 : The wavelength of the light mainly emitted from the light-emitting element L OR : Resonator length RDBR : The radius of curvature of the concave mirror portion composed of the first light reflection layer and the film thickness modulation layer [D02] A mode loss action site that is provided on the second surface of the second compound semiconductor layer and constitutes a mode loss action region that acts on the increase and decrease of the oscillation mode loss A second electrode formed across the mode loss action site from the second surface of the second compound semiconductor layer, and A first electrode electrically connected to the first compound semiconductor layer further includes The second light reflection layer is formed on the second electrode In the stacked structure, a current injection region, a current non-injection / inner region surrounding the current injection region, and a current non-injection / outer region surrounding the current non-injection / inner region are formed The light emitting element according to [D01], wherein the orthographic image of the mode loss action region and the orthographic image of the current non-injection / outer region overlap [D03] The radius r' of the effective region in the concave mirror portion composed of the first light reflection layer and the film thickness modulation layer DBR is ω 0 ≦r' DBR ≦20·ω 0 The light emitting element according to [D01] or [D02] that satisfies the above [D04] D CI ≧ω 0 The light emitting element according to any one of [D01] to [D03] that satisfies the above [D05] R DBR ≦1×10 -3 m. The light emitting element according to any one of [D01] to [D04] that satisfies the above [E01] 《Light Emitting Element of the Second Configuration》 A mode loss action site that is provided on the second surface of the second compound semiconductor layer and constitutes a mode loss action region that acts on the increase and decrease of the oscillation mode loss A second electrode formed across the mode loss action site from the second surface of the second compound semiconductor layer, and A first electrode electrically connected to the first compound semiconductor layer further includes The second light reflection layer is formed on the second electrode, In the laminate structure, a current injection region, a current non-injection / inner region surrounding the current injection region, and a current non-injection / outer region surrounding the current non-injection / inner region are formed. The light-emitting device according to any one of [C01] to [C03], wherein an orthographic image of the mode loss action region and an orthographic image of the current non-injection / outer region overlap. The light-emitting device according to [E01], wherein the current non-injection / outer region is located below the mode loss action region. [E03] Let the area of the orthographic image of the current injection region be S 1 , and the area of the orthographic image of the current non-injection / inner region be S 2 When it is set as, 0.01 ≦ S 1 / (S 1 + S 2 ) ≦ 0.7 The light-emitting device according to [E01] or [E02] that satisfies. [E04] The light-emitting device according to any one of [E01] to [E03], wherein the current non-injection / inner region and the current non-injection / outer region are formed by ion injection into the laminate structure. [E05] The light-emitting device according to [E04], wherein the ion species is at least one ion selected from the group consisting of boron, proton, phosphorus, arsenic, carbon, nitrogen, fluorine, oxygen, germanium, and silicon. [E06] 《Light-emitting device of the second-B configuration》 The light-emitting device according to any one of [E01] to [E05], wherein the current non-injection / inner region and the current non-injection / outer region are formed by plasma irradiation on the second surface of the second compound semiconductor layer, or ashing treatment on the second surface of the second compound semiconductor layer, or reactive ion etching treatment on the second surface of the second compound semiconductor layer. [E07] 《Light-emitting device of the second-C configuration》 The light-emitting device according to any one of [E01] to [E06], wherein the second light reflection layer has a region that reflects or scatters the light from the first light reflection layer toward the outside of the resonator structure constituted by the first light reflection layer and the second light reflection layer. [E08]Let the optical distance from the light-emitting layer in the current injection region to the second surface of the second compound semiconductor layer be L 2 , and when the optical distance from the light-emitting layer in the mode loss action region to the top surface of the mode loss action site is L 0 , L 0 >L 2 The light-emitting device according to any one of [E04] to [E07] that satisfies [E09]Light having the generated higher-order mode is dissipated outward from the resonator structure constituted by the first light reflection layer and the second light reflection layer by the mode loss action region, whereby the oscillation mode loss increases. The light-emitting device according to any one of [E04] to [E08]. [E10]The mode loss action site is made of a dielectric material, a metal material, or an alloy material. The light-emitting device according to any one of [E04] to [E09]. [E11]The mode loss action site is made of a dielectric material, and the optical film thickness of the mode loss action site is a value that deviates from an integer multiple of 1 / 4 of the wavelength of the light generated in the light-emitting device. The light-emitting device according to [E10]. [E12]The mode loss action site is made of a dielectric material, and the optical film thickness of the mode loss action site is an integer multiple of 1 / 4 of the wavelength of the light generated in the light-emitting device. The light-emitting device according to [E10]. [E13]《Light-emitting device of the second-D configuration》 A convex portion is formed on the second surface side of the second compound semiconductor layer, and the mode loss action site is formed on the region of the second surface of the second compound semiconductor layer surrounding the convex portion. The light-emitting device according to any one of [E01] to [E03]. [E14]Let the optical distance from the light-emitting layer in the current injection region to the second surface of the second compound semiconductor layer be L 2 , and when the optical distance from the light-emitting layer in the mode loss action region to the top surface of the mode loss action site is L 0 , L 0 <L 2 The light-emitting device according to [E13] that satisfies [E15]The light having the generated higher-order mode is confined to the current injection region and the current non-injection / inner region by the mode loss action region, whereby the oscillation mode loss is reduced, which is the light-emitting element described in [E13] or [E14]. [E16]The mode loss action site is the light-emitting element described in any one of [E13] to [E15] made of a dielectric material, a metal material, or an alloy material. [E17]The second electrode is the light-emitting element described in any one of [E01] to [E16] made of a transparent conductive material. [F01]《Light-emitting element of the third configuration》 A second electrode formed on the second surface of the second compound semiconductor layer, A second light reflection layer formed on the second electrode, A mode loss action site provided on the first surface of the first compound semiconductor layer and constituting a mode loss action region that affects the increase or decrease of the oscillation mode loss, and A first electrode electrically connected to the first compound semiconductor layer, further comprising, The first light reflection layer and the film thickness modulation layer are formed across the mode loss action site from the first surface of the first compound semiconductor layer, In the laminated structure, a current injection region, a current non-injection / inner region surrounding the current injection region, and a current non-injection / outer region surrounding the current non-injection / inner region are formed, The light-emitting element described in any one of [C01] to [C03], wherein the orthographic image of the mode loss action region and the orthographic image of the current non-injection / outer region overlap. [F02]Let the area of the orthographic image of the current injection region be S 1 , and the area of the orthographic image of the current non-injection / inner region be S 2 . When 0.01 ≦ S 1 ’ / (S 1 ’ + S 2 ’) ≦ 0.7 which satisfies the light-emitting element described in [F01]. [F03]《Light-emitting element of the third-A configuration》 The current non-injection inner region and the current non-injection outer region are light-emitting elements described in [F01] or [F02] formed by ion implantation into the stacked structure. The light-emitting element described in [F03], wherein the ion species is at least one ion selected from the group consisting of boron, proton, phosphorus, arsenic, carbon, nitrogen, fluorine, oxygen, germanium, and silicon. [F05] "Light-emitting element of the third-B configuration" The current non-injection inner region and the current non-injection outer region are light-emitting elements according to any one of [F01] to [F04], formed by plasma irradiation on the second surface of the second compound semiconductor layer, or ashing treatment on the second surface of the second compound semiconductor layer, or reactive ion etching treatment on the second surface of the second compound semiconductor layer. [F06] "Light-emitting element of the third-C configuration" The second light reflection layer has a region that reflects or scatters the light from the first light reflection layer toward the outside of the resonator structure constituted by the first light reflection layer and the second light reflection layer. The light-emitting element according to any one of [F01] to [F05]. [F07] Let the optical distance from the light-emitting layer in the current injection region to the first surface of the first compound semiconductor layer be L 1 ', and the optical distance from the light-emitting layer in the mode loss action region to the top surface of the mode loss action site be L 0 '. When L 0 '> L 1 ' The light-emitting element according to any one of [F03] to [F06] that satisfies [F08] The light having the generated higher-order mode is dissipated toward the outside of the resonator structure constituted by the first light reflection layer and the second light reflection layer by the mode loss action region, thereby increasing the oscillation mode loss. The light-emitting element according to any one of [F03] to [F07]. [F09] The mode loss action site is made of a dielectric material, a metal material, or an alloy material. The light-emitting element according to any one of [F03] to [F08]. [F10] The mode loss action site is made of a dielectric material, The optical film thickness of the mode loss action site is a value that deviates from an integer multiple of 1 / 4 of the wavelength of the light generated in the light-emitting element. The light-emitting element described in [F09]. [F11] The mode loss action site is made of a dielectric material, The optical film thickness of the mode loss action site is an integer multiple of 1 / 4 of the wavelength of the light generated in the light-emitting element. The light-emitting element described in [F09]. [F12] 《Light-emitting element of the 3-D structure》 A convex portion is formed on the first surface side of the first compound semiconductor layer, The mode loss action site is formed on the region of the first surface of the first compound semiconductor layer surrounding the convex portion. The light-emitting element described in [F01] or [F02]. [F13] The optical distance from the light-emitting layer in the current injection region to the first surface of the first compound semiconductor layer is L 1 ’, and the optical distance from the light-emitting layer in the mode loss action region to the top surface of the mode loss action site is L 0 ’ When, L 0 ’ < L 1 ’ Satisfying the light-emitting element described in [F12]. [F14] A convex portion is formed on the first surface side of the first compound semiconductor layer, The mode loss action site is composed of the region of the first surface of the first compound semiconductor layer surrounding the convex portion. The light-emitting element described in [F01] or [F02]. [F15] The light having the generated higher-order mode is confined to the current injection region and the current non-injection / inner region by the mode loss action region, thereby reducing the oscillation mode loss. The light-emitting element described in any one of [F12] to [F14]. [F16] The mode loss action site is made of a dielectric material, a metal material, or an alloy material. The light-emitting element described in any one of [F12] to [F15]. [F17] The second electrode is made of a transparent conductive material. The light-emitting element described in any one of [F01] to [F16]. [G01] 《Light-emitting element of the 4th structure》 The light-emitting device according to any one of [C01] to [F17], wherein at least two light absorption material layers are formed in a laminated structure including a second electrode, in parallel with a virtual plane occupied by the light-emitting layer. [G02] The light-emitting device according to [G01], wherein at least four light absorption material layers are formed. [G03] The oscillation wavelength is λ 0 , the equivalent refractive index n of the entire portion of the laminated structure located between the two light absorption material layers and the light absorption material layer eq , the distance L between the light absorption material layers Abs When it is set as 0.9×{(m·λ 0 ) / (2·n eq )}≦L Abs ≦1.1×{(m·λ 0 ) / (2·n eq )} The light-emitting device according to [G01] or [G02] that satisfies the above. However, m is 1 or any integer of 2 or more including 1. [G04] The thickness of the light absorption material layer is λ 0 / (4·n eq ) or less, and the light-emitting device according to any one of [G01] to [G03]. [G05] The light-emitting device according to any one of [G01] to [G04], wherein the light absorption material layer is located at the lowest amplitude portion generated in the standing wave of light formed inside the laminated structure. [G06] The light-emitting device according to any one of [G01] to [G05], wherein the light-emitting layer is located at the maximum amplitude portion generated in the standing wave of light formed inside the laminated structure. [G07] The light absorption material layer has a light absorption coefficient that is 2 times or more the light absorption coefficient of the compound semiconductor constituting the laminated structure, and the light-emitting device according to any one of [G01] to [G06]. [G08]The light absorption material layer is composed of at least one material selected from the group consisting of a compound semiconductor material having a narrower bandgap than the compound semiconductor constituting the laminated structure, an impurity-doped compound semiconductor material, a transparent conductive material, and a light reflection layer constituent material having light absorption characteristics, and is the light-emitting element according to any one of [G01] to [G07]. [H01]A compound semiconductor substrate is disposed between the first surface of the first compound semiconductor layer and the first light reflection layer and the film thickness modulation layer, and is the light-emitting element according to any one of [C01] to [G08]. [H02]The compound semiconductor substrate is made of a GaN substrate, and is the light-emitting element according to [H01]. [H03]The concave mirror portion composed of the first light reflection layer and the film thickness modulation layer is composed of a base portion formed by a protruding portion of the compound semiconductor substrate, and a film thickness modulation layer and a multilayer light reflection film formed on at least a part of the surface of the base portion, and is the light-emitting element according to [H01] or [H02]. [H04]The concave mirror portion composed of the first light reflection layer and the film thickness modulation layer is composed of a base portion formed on the compound semiconductor substrate, and a multilayer light reflection film and a film thickness modulation layer formed on at least a part of the surface of the base portion, and is the light-emitting element according to [H01] or [H02]. [H05]The first light reflection layer and the film thickness modulation layer are formed on the first surface of the first compound semiconductor layer, and is the light-emitting element according to any one of [C01] to [G08]. [H06]The value of the thermal conductivity of the laminated structure is higher than the value of the thermal conductivity of the first light reflection layer and the film thickness modulation layer, and is the light-emitting element according to any one of [C01] to [H05]. [H07]Let the radius of curvature of the concave mirror portion of the light-emitting element be R DBR When it is set as such, R DBR ≦1×10 -3 m is satisfied, and it is the light-emitting element according to any one of [C01] to [H06]. [H08]A convex-shaped portion is formed around the first light reflection layer and the film thickness modulation layer, and the first light reflection layer does not protrude from the convex-shaped portion, and is the light-emitting element according to any one of [C01] to [H07]. [J01]《Manufacturing method of light-emitting element》 On the compound semiconductor substrate, A first compound semiconductor layer having a first surface and a second surface facing the first surface, A light-emitting layer facing the second surface of the first compound semiconductor layer, and A second compound semiconductor layer having a first surface facing the light-emitting layer and a second surface facing the first surface, After forming a stacked structure composed of a GaN-based compound semiconductor in which these are stacked, A second electrode and a second light reflection layer are formed on the second compound semiconductor layer, and then, After fixing the second light reflection layer to a support substrate, The compound semiconductor substrate is thinned, and then, After forming a base portion composed of a protruding portion on the exposed surface of the compound semiconductor substrate, or after forming a base portion composed of a protruding portion on the exposed surface of the compound semiconductor substrate, A film thickness modulation layer and a first light reflection layer are formed on at least a part of the base portion, and a first electrode electrically connected to the first compound semiconductor layer is formed. Comprising each step, The base portion constitutes a concave mirror portion, The second light reflection layer has a flat shape, a method for manufacturing a light-emitting element.

Description of reference numerals

[0248] 11 ··· Compound semiconductor substrate (substrate for manufacturing light-emitting elements), 11a ··· First surface of the compound semiconductor substrate (substrate for manufacturing light-emitting elements) facing the first compound semiconductor layer, 11a' ··· Protrusion on the first surface of the compound semiconductor substrate, 11a'' ··· Dimple, 11b ··· Second surface of the compound semiconductor substrate (substrate for manufacturing light-emitting elements) facing the first compound semiconductor layer, 11A ··· Convex-shaped portion, 20 ··· Stacked structure, 21 ··· First compound semiconductor layer, 21a ··· First surface of the first compound semiconductor layer, 21b ··· Second surface of the first compound semiconductor layer, 21d, 21e ··· Protrusions on the first surface of the first compound semiconductor layer, 22 ··· Second compound semiconductor layer, 22a ··· First surface of the second compound semiconductor layer, 22b ··· Second surface of the second compound semiconductor layer, 23 ··· Light-emitting layer (active layer), 31 ··· First electrode, 32 ··· Second electrode, 33 ··· Pad electrode, 34 ··· Insulating layer (current constriction layer), 34A ··· Opening provided in the insulating layer (current constriction layer), 41 ··· First light reflection layer, 41A ··· First thin film, 41B ··· Second thin film, 41a ··· Inclined portion formed on the first compound semiconductor layer, 42 ··· Second light reflection layer, 42A ··· Gradually tapered inclined portion formed on the second light reflection layer, 43 ··· Concave mirror portion, 43A ··· Concave portion, 43a ··· Interface facing the stacked structure of the effective region in the concave mirror portion of the first light reflection layer, 44 ··· Effective region in the concave mirror portion of the first light reflection layer, 45A, 45B, 45D, 45E, 45F ··· Base portion, 45c ··· Protrusion, 46 ··· Multilayer light reflection film, 47 ··· Planarization film, 48 ··· Bonding layer, 49 ··· Support substrate, 51, 61 ··· Current injection region, 52, 62 ··· Current non-injection / inner region, 53, 63 ··· Current non-injection / outer region, 54, 64 ··· Mode loss action site (mode loss action layer), 54A, 54B, 64A ··· Openings formed in the mode loss action site, 55, 65 ··· Mode loss action region, 71 ··· Light absorption material layer, 80 ··· Film thickness modulation layer, 81 ··· Third thin film, 81A ··· 3A thin film, 81B ··· 3B thin film, 82 ··· Fourth thin film, 82A ··· 4A thin film, 82B ··· 4B thin film, 91 ··· Light absorption material layer

Claims

1. a first light reflecting layer, a laminated structure, and a second light reflecting layer are laminated together, the laminated structure is formed by laminating a first compound semiconductor layer, a light emitting layer, and a second compound semiconductor layer from the first light reflecting layer side, light from the laminated structure is emitted to the outside via the first light reflecting layer or the second light reflecting layer, The first light reflective layer has a structure in which at least two types of thin films are alternately laminated, a thickness modulation layer is provided between the laminated structure and the first light reflective layer, the first light reflecting layer and the thickness modulation layer constitute a concave mirror portion having a concave shape with respect to the laminated structure, The second light reflecting layer has a flat shape, A light emitting device, comprising: a compound semiconductor substrate disposed between the first surface of the first compound semiconductor layer and the first light reflecting layer and the thickness modulation layer.

2. The compound semiconductor substrate is a GaN substrate. The light-emitting device according to claim 1 .

3. The concave mirror portion, which is composed of the first light reflecting layer and the thickness modulation layer, is composed of a base portion formed of a protruding portion of the compound semiconductor substrate, and the thickness modulation layer and a multilayer light reflecting film formed on at least a part of the surface of the base portion. The light-emitting device according to claim 1 .

4. The concave mirror portion, which is composed of the first light reflecting layer and the thickness modulation layer, is composed of a base portion formed on the compound semiconductor substrate, and a multilayer light reflecting film and the thickness modulation layer formed on at least a part of the surface of the base portion. The light-emitting device according to claim 1 .

5. The thermal conductivity value of the laminated structure is higher than the thermal conductivity values ​​of the first light reflecting layer and the thickness modulation layer. The light-emitting device according to claim 1 .

6. The radius of curvature of the concave mirror portion is R DBR Then, R DBR ≦1×10 -3 Satisfy m The light-emitting device according to claim 1 .

7. A convex portion is formed around the first light reflecting layer and the thickness modulation layer, and the first light reflecting layer does not protrude from the convex portion. The light-emitting device according to claim 1 .

8. The cavity length is L OR Then, 1×10 -5 m≦L OR Satisfy The light-emitting device according to claim 1 .

9. When the first light reflecting layer and the thickness modulation layer are cut along a virtual plane including the stacking direction of the stacked structure, a figure drawn by an interface of a part of the concave mirror portion composed of the first light reflecting layer and the thickness modulation layer facing the stacked structure is a part of a circle or a part of a parabola. The light-emitting device according to claim 1 .

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