Light emitting element and method for manufacturing the same

Abstract

A light emitting element comprises: a laminated structure (20) in which a first compound semiconductor layer (21), an active layer (23) and a second compound semiconductor layer (22) are laminated; a first electrode (31) electrically connected to the first compound semiconductor layer (21); and a second electrode (32) and a second light reflecting layer (42) formed on the second compound semiconductor layer (22). A protrusion (43) is formed on a first surface of the first compound semiconductor layer (21), a smooth layer (44) is formed at least on the protrusion (43), the protrusion (43) and the smooth layer (44) constitute a concave mirror portion, the first light reflecting layer (41) is formed on at least a portion of the smooth layer (44), and the second light reflecting layer (42) has a flat shape.

Description

Technical Field

[0001] The present disclosure relates to a light emitting element and a method of manufacturing the same, and more particularly, to a light emitting element including a surface emitting laser element (VCSEL) and a method of manufacturing the same. Background Art

[0002] In a light-emitting element including a surface-emitting laser element (VCSEL), laser oscillation generally occurs by causing resonance of a laser beam between two light-reflecting layers (distributed Bragg reflector (DBR) layers). Then, in a surface-emitting laser element having a laminated structure in which an n-type compound semiconductor layer, an active layer (light-emitting layer) including a compound semiconductor, and a p-type compound semiconductor layer are laminated, generally, a second electrode including a transparent conductive material is formed on the p-type compound semiconductor layer, and a second light-reflecting layer including a laminated structure of an insulating material or the like is formed on the second electrode. In addition, on the n-type compound semiconductor layer side, a first light-reflecting layer having a laminated structure of an insulating material or the like is formed. Note that, for convenience, an axis passing through the center of a resonator formed by two light-reflecting layers is set as a Z axis, and a virtual plane orthogonal to the Z axis is referred to as an XY plane.

[0003] Incidentally, in the case where the laminated structure includes a GaAs-based compound semiconductor, the resonator length L OR On the other hand, in the case where the laminated structure includes a GaN-based compound semiconductor, the resonator length L OR It is often several times or more longer than the wavelength of the laser beam emitted from the surface emitting laser element. That is, the resonator length L OR Much longer than 1μm.

[0004] Then, when the resonator length L OR When it becomes longer in this way, the diffraction loss increases, making it difficult to generate laser oscillation. That is, there is a possibility that the light-emitting element is used as an LED rather than as a surface-emitting laser element. Here, "diffraction loss" refers to the following phenomenon: because light generally tends to expand due to the diffraction effect, the laser beam reciprocating in the resonator gradually disperses to the outside of the resonator. In order to solve such a problem, as a technology for providing a concave mirror function to the light reflecting layer, for example, there are Japanese Patent Application Publication No. 2006-114753, Japanese Patent Application Publication No. 2000-022277 and International Publication WO 2018 / 083877A1.

[0005] Reference List

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2006-114753

[0008] Patent Document 2: Japanese Patent Application Publication No. 2000-022277

[0009] Patent Document 3: International Publication WO 2018 / 083877 A1 Summary of the invention

[0010] Problems to be solved by the present invention

[0011] Incidentally, in order to provide the first light reflecting layer that functions as a concave mirror, a concave portion must be formed on the substrate. However, when the concave portion is formed on the substrate, concave-convex portions are often generated on the concave portion. Then, the following problem arises as a result: concave-convex portions are also generated on the first light reflecting layer formed on the substrate, light is scattered, and the threshold of the light emitting element is not reduced, thereby causing the problem of reduced luminous efficiency. Therefore, it is extremely important that the surface of the substrate used to form the first light reflecting layer is smooth. However, the patent disclosure described above does not mention anything about smoothing the surface of the substrate used to form the first light reflecting layer that functions as a concave mirror.

[0012] Therefore, an object of the present disclosure is to provide a light emitting element having a configuration and a structure capable of forming a smooth first light reflecting layer, and a method for manufacturing the same.

[0013] Solution to the problem

[0014] The light emitting element of the present disclosure for achieving the above-mentioned object comprises:

[0015] A laminated structure, wherein a first compound semiconductor layer, an active layer, and a second compound semiconductor layer are laminated, the first compound semiconductor layer including a first surface and a second surface facing the first surface, the active layer facing the second surface of the first compound semiconductor layer, and the second compound semiconductor layer including a first surface facing the active layer and a second surface facing the first surface;

[0016] a first electrode electrically connected to the first compound semiconductor layer; and

[0017] A second electrode and a second light reflecting layer are formed on a second surface of the second compound semiconductor layer, wherein

[0018] forming a protrusion on the first surface side of the first compound semiconductor layer,

[0019] forming a smooth layer at least on the protruding portion,

[0020] The protrusion and the smooth layer constitute the concave mirror part.

[0021] forming a first light reflecting layer on at least a portion of the smoothing layer, and

[0022] The second light reflecting layer has a flat shape.

[0023] A method for manufacturing a light emitting element according to a first aspect of the present disclosure for achieving the above-mentioned object comprises the following steps:

[0024] forming a laminated structure in which a first compound semiconductor layer, an active layer, and a second compound semiconductor layer are laminated, the first compound semiconductor layer including a first surface and a second surface facing the first surface, the active layer facing the second surface of the first compound semiconductor layer, and the second compound semiconductor layer including a first surface facing the active layer and a second surface facing the first surface; then,

[0025] forming a second electrode and a second light reflecting layer on the second surface of the second compound semiconductor layer; thereafter,

[0026] forming a protrusion on the first surface side of the first compound semiconductor layer; then,

[0027] A smoothing layer is formed at least on the protruding portion, and then the surface of the smoothing layer is smoothed; thereafter,

[0028] A first light reflecting layer is formed on at least a portion of the smoothing layer, and a first electrode electrically connected to the first compound semiconductor layer is formed, wherein:

[0029] The protrusion and the smooth layer constitute a concave mirror portion, and

[0030] The second light reflecting layer has a flat shape.

[0031] A method for manufacturing a light emitting element according to a second aspect of the present disclosure for achieving the above-mentioned object comprises the following steps:

[0032] forming a laminated structure in which a first compound semiconductor layer, an active layer, and a second compound semiconductor layer are laminated, the first compound semiconductor layer including a first surface and a second surface facing the first surface, the active layer facing the second surface of the first compound semiconductor layer, and the second compound semiconductor layer including a first surface facing the active layer and a second surface facing the first surface; then,

[0033] forming a second electrode and a second light reflecting layer on the second surface of the second compound semiconductor layer; thereafter,

[0034] forming a protrusion on the first surface side of the first compound semiconductor layer; then, smoothing the surface of the protrusion; then,

[0035] A first light reflecting layer is formed on at least a portion of the protrusion, and a first electrode electrically connected to the first compound semiconductor layer is formed, wherein:

[0036] The protrusion constitutes a concave mirror portion, and the second light reflecting layer has a flat shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic partial end view of the light emitting element of Example 1.

[0038] Figure 2 1 is a schematic partial end view of a substrate and the like for explaining a method for manufacturing a light emitting element of Example 1.

[0039] Figure 3 It is a continuation Figure 2 A schematic partial end view of a substrate, etc., for illustrating a method for manufacturing a light-emitting element of Example 1.

[0040] Figure 4 It is a continuation Figure 3 A schematic partial end view of a substrate, etc., for illustrating a method for manufacturing a light-emitting element of Example 1.

[0041] Figure 5 It is a continuation Figure 4 A schematic partial end view of a substrate, etc., for illustrating a method for manufacturing a light-emitting element of Example 1.

[0042] Figure 6 It is a continuation Figure 5 A schematic partial end view of a substrate, etc., for illustrating a method for manufacturing a light-emitting element of Example 1.

[0043] Figure 7 is a schematic partial end view of the light emitting element of Example 2.

[0044] Figure 8 is a schematic partial end view of the light emitting element of Example 3.

[0045] Fig. 9 is a schematic partial end view of a variation of the light emitting element of Example 3.

[0046] Fig. 10A and Fig. 10B is a schematic partial end view of the light emitting element of Example 4.

[0047] Fig.11 is a schematic partial end view of the light emitting element of Example 6.

[0048] Fig. 12A and Fig. 12B is a schematic partial end view of a laminated structure and the like for explaining a method for manufacturing a light emitting element of Example 6.

[0049] Fig.13 (A), (B) and (C) are conceptual diagrams illustrating the light field intensities of a conventional light emitting element, a light emitting element of Example 6 and a light emitting element of Example 9, respectively.

[0050] Fig.14 is a schematic partial end view of the light emitting element of Example 7.

[0051] Fig.15 is a schematic partial end view of the light emitting element of Example 8.

[0052] Fig.16 is a schematic partial end view of the light emitting element of Example 9.

[0053] Fig.17 Yes Fig.16 Schematic partial end view of a cutaway main portion of the light emitting element of Example 9 illustrated in FIG.

[0054] Fig.18 is a schematic partial end view of the light emitting element of Example 10.

[0055] Fig.19 is a schematic partial end view of a light emitting element of Example 10 and a diagram in which two longitudinal modes, longitudinal mode A and longitudinal mode B, are superimposed on each other.

[0056] Fig. 20 is a schematic partial end view of a variation of the light emitting element of Example 1.

[0057] Fig.21 is a schematic partial end view of a variation of the light emitting element of Example 2.

[0058] Fig. 22 It is a conceptual diagram when it is assumed that a Fabry-Perot resonator is sandwiched between two concave mirror portions having the same radius of curvature in the light emitting element of the present disclosure.

[0059] Fig.23 The value of ω0 and the resonator length L are shown in FIG. OR and the radius of curvature R on the inner surface of the first light reflecting layer DBR A graph showing the relationship between the values ​​of .

[0060] Fig.24 The value of ω0 and the resonator length L are shown in FIG. OR and the radius of curvature R on the inner surface of the first light reflecting layer DBR A graph showing the relationship between the values ​​of .

[0061] Fig.25A and Fig.25B ] are respectively a diagram schematically illustrating a converged state of the laser beam when the value of ω0 is "positive" and a diagram schematically illustrating a converged state of the laser beam when the value of ω0 is "negative".

[0062] Fig.26A and Fig.26B is a conceptual diagram schematically illustrating longitudinal modes existing in a gain spectrum determined by an active layer.

[0063] Fig. 27 Schematic diagram illustrating the crystal structure of a hexagonal nitride semiconductor for explaining polar planes, nonpolar planes, and semipolar planes in a nitride semiconductor crystal. DETAILED DESCRIPTION

[0064] Hereinafter, the present disclosure will be described on the basis of examples with reference to the accompanying drawings, but the present disclosure is not limited to the examples, and various numerical values ​​and materials in the examples are illustrative. Note that the description will be given in the following order.

[0065] 1. General description of the light-emitting element of the present disclosure and the method for manufacturing the light-emitting element according to the first aspect to the second aspect of the present disclosure

[0066] 2. Example 1 (Light-emitting element of the present disclosure and method for manufacturing the light-emitting element according to the first aspect of the present disclosure)

[0067] 3. Example 2 (variation of Example 1)

[0068] 4. Example 3 (Another variation of Example 1)

[0069] 5. Example 4 (Method for manufacturing a light-emitting element according to the second aspect of the present disclosure)

[0070] 6. Example 5 (Variation of Examples 1 to 4, the light emitting element has the first configuration)

[0071] 7. Example 6 (Variation of Examples 1 to 5, the light emitting element has the second configuration A)

[0072] 8. Example 7 (variation of Example 6, light emitting element has second configuration B)

[0073] 9. Example 8 (Variation of Example 6 to Example 7, the light emitting element has the second configuration C)

[0074] 10. Example 9 (Variation of Examples 6 to 8, the light emitting element has the second configuration D)

[0075] 11. Example 10 (Variation of Examples 1 to 9, the light emitting element has a third configuration)

[0076] 12. Example 11 (Variation of Example 10)

[0077] 13. Example 12 (Another variation of Example 10)

[0078] 14. Others

[0079] <General Description Related to the Light-Emitting Element of the Present Disclosure and the Method for Manufacturing the Light-Emitting Element According to the First Aspect to the Second Aspect of the Present Disclosure>

[0080] In the light-emitting element of the present disclosure and the method for manufacturing the light-emitting element according to the first aspect of the present disclosure, the "surface of the smooth layer" refers to the surface of the smooth layer forming an interface between the smooth layer and the first light reflecting layer. In addition, in the method for manufacturing the light-emitting element according to the second aspect of the present disclosure, the "surface of the protrusion" refers to the surface of the protrusion forming an interface between the protrusion and the first light reflecting layer.

[0081] In the light-emitting element of the present disclosure and the light-emitting element obtained by the method for manufacturing a light-emitting element according to the first aspect of the present disclosure (hereinafter, these light-emitting elements may be simply collectively referred to as "the light-emitting element according to the first aspect of the present disclosure, etc."), it is preferred that the value of the surface roughness Ra1 of the smooth layer at the interface between the smooth layer and the first light reflecting layer is smaller than the value of the surface roughness Ra2 of the protrusion at the interface between the protrusion and the smooth layer. Then, in this case, it is desirable that the value of the surface roughness Ra1 is less than or equal to 1.0 nm. In addition, in the light-emitting element obtained by the method for manufacturing a light-emitting element according to the second aspect of the present disclosure (hereinafter, the light-emitting element may be referred to as "the light-emitting element according to the second aspect of the present disclosure, etc."), it is desirable that the value of the surface roughness Ra2 of the protrusion at the interface between the protrusion and the first light reflecting layer is less than or equal to 1.0 nm. Note that the surface roughness Ra is defined in JIS B-610:2001. Specifically, the surface roughness Ra can be measured by observation based on AFM or cross-sectional TEM.

[0082] In the light emitting element according to the first aspect of the present disclosure and the like including the above-described preferred embodiments, it is possible to adopt a configuration in which the average thickness T of the smoothing layer at the top of the protrusion is C The average thickness T of the smooth layer at the edge of the protrusion P Thin implementation. As T P / T C The value of can be exemplified as 0.01≤T P / T C ≤0.5, but not limited thereto. In addition, as T C The value of can be exemplified as 1×10 -8 m to 2×10 -6 m.

[0083] Furthermore, in the light emitting element according to the first aspect of the present disclosure and the like including various preferred embodiments described above, a configuration in which the radius of curvature of the smoothing layer is 1×10 -5 m to 1×10 -3m. In addition, in the light emitting element according to the second aspect of the present disclosure, etc., a configuration in which the curvature radius of the protrusion is 1×10 -5 m to 1×10 -3 m implementation method.

[0084] In addition, in the light-emitting element according to the first aspect of the present disclosure, including the various preferred embodiments described above, an embodiment can be adopted in which the material constituting the smoothing layer is at least one material selected from the group consisting of a dielectric material, a spin-on-glass-based material, a low-melting-point glass material, a semiconductor material, and a resin.

[0085] In addition, in the method for manufacturing a light-emitting element according to the first aspect of the present disclosure including the above-mentioned various preferred embodiments, a mode in which the smoothing treatment on the surface of the smoothing layer is based on wet etching may be adopted, or alternatively, an embodiment in which the smoothing treatment on the surface of the smoothing layer is based on dry etching may be adopted. In addition, in the method for manufacturing a light-emitting element according to the second aspect of the present disclosure, an embodiment in which the smoothing treatment on the surface of the protrusion is based on wet etching may be adopted, or alternatively, an embodiment in which the smoothing treatment on the surface of the protrusion is based on dry etching may be adopted.

[0086] In the manufacturing method of the light-emitting element according to the first aspect to the second aspect of the present disclosure, in the case where a smoothing process is performed on the surface of the smoothing layer by wet etching, examples of wet etching include a chemical mechanical polishing method (CMP method) and an immersion method. Then, in this case, although depending on the material constituting the smoothing layer or the protrusion, examples of polishing liquid and etching solution include colloidal silica, sodium bicarbonate, tetramethylammonium hydroxide (TMAH), hydrogen fluoride water, pure water and pure water (deionized water). In the case where a smoothing process is performed on the surface of the smoothing layer by dry etching, examples of dry etching include a reactive ion etching method (RIE method). Specifically, in the case where the smoothing layer includes, for example, Ta2O5, a polishing method using colloidal silica can be adopted, an immersion method using HF can be adopted, and an RIE method using a fluorine-based gas can be adopted.

[0087] In the light-emitting element according to the first aspect of the present disclosure, etc., examples of dielectric materials constituting the smoothing layer include Ta2O5, Nb2O5, SiN, AlN, SiO2, Al2O3, HfO2, TiO2, and Bi2O3. Examples of spin-on glass-based materials include silicate-based materials, siloxane-based materials, methylsiloxane-based materials, and silazane-based materials. Examples of low-melting-point glass materials include glass materials containing bismuth (Bi) oxides, glass materials containing barium (Ba) oxides, glass materials containing tin (Sn) oxides, glass materials containing phosphorus (P) oxides, and glass materials containing lead (Pb) oxides. Examples of semiconductor materials include GaN, GaAs, and InP. Note that in the case where the smoothing layer and the protrusion include semiconductor materials, lattice matching between the smoothing layer and the protrusion is not required, so that the doping type and doping amount of impurities contained in the semiconductor material constituting the smoothing layer and the crystal orientation can be different from the doping type and doping amount and crystal orientation of the protrusion, and can be formed not only by an epitaxial growth method but also by a PVD method such as a sputtering method. Examples of the resin constituting the smooth layer include epoxy-based resins, silicone-based resins, benzocyclobutene (BCB) resins, polyimide-based resins, and phenolic resins. The smooth layer may also have a structure in which layers including these materials are laminated.

[0088] In the light-emitting element according to the first aspect to the second aspect of the present disclosure, etc., the protrusion is formed on the first surface side of the first compound semiconductor layer, but the protrusion may be formed on the substrate, or may be formed on the first compound semiconductor layer. Alternatively, the protrusion may be formed on the exposed surface of the substrate or the first compound semiconductor layer based on another material different from the material of the substrate or the first compound semiconductor layer, and in this case, examples of materials constituting the protrusion include transparent dielectric materials such as TiO2, Ta2O5 or SiO2, silicone-based resins and epoxy-based resins, and the protrusion is formed on the first surface of the substrate (described later) or the exposed surface of the first compound semiconductor layer.

[0089] In the case of a light-emitting element according to the first aspect to the second aspect of the present disclosure including the above-mentioned various preferred embodiments and configurations, a surface emitting laser element (vertical cavity surface emitting laser (VCSEL)) that emits a laser beam through a first light reflecting layer can be configured, or alternatively, a surface emitting laser element that emits a laser beam through a second light reflecting layer can also be configured.

[0090] In the light-emitting element according to the first aspect to the second aspect of the present disclosure including the above-mentioned various preferred embodiments, the following embodiment can be adopted: when the first light reflecting layer is cut by a virtual plane including the lamination direction of the laminated structure (a virtual plane including the Z axis) (hereinafter, for convenience, referred to as "the inner surface of the first light reflecting layer"), the figure drawn by the surface of the first light reflecting layer in contact with the smooth layer or the protrusion is a part of a circle or a part of a parabola. There may be a case where the figure is not strictly a part of a circle, or there may be a case where the figure is not strictly a part of a parabola. That is, the case where the figure is roughly a part of a circle or the case where the figure is roughly a part of a parabola is also included in the "figure is a part of a circle or a part of a parabola". Such a part (region) of the first light reflecting layer that is a part of a circle or a part of a parabola can be referred to as an "effective region of the first light reflecting layer". By measuring the shape of the interface (the interface between the smooth layer and the first light reflecting layer or the interface between the protrusion and the first light reflecting layer) with a measuring instrument and analyzing the obtained data based on the least squares method, the figure drawn by the inner surface of the first light reflecting layer can be obtained.

[0091] In the light-emitting elements according to the first aspect to the second aspect of the present disclosure, the laminated structure may specifically include a GaN-based compound semiconductor. More specifically, examples of GaN-based compound semiconductors include GaN, AlGaN, InGaN, and AlInGaN. In addition, if necessary, these compound semiconductors may contain boron (B) atoms, thallium (Tl) atoms, arsenic (As) atoms, phosphorus (P) atoms, and antimony (Sb) atoms. It is desirable that the active layer has a quantum well structure. Specifically, the active layer may have a single quantum well structure (SQW structure), or may have a multiple quantum well structure (MQW structure). The active layer having a quantum well structure has a structure in which at least one well layer and one barrier layer are laminated, and as a combination of (a compound semiconductor constituting a well layer and a compound semiconductor constituting a barrier layer), (In can be exemplified). 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, AlGaN).

[0092] Alternatively, in the light emitting elements and the like according to the first to second aspects of the present disclosure, specifically, the laminated structure may further include a GaAs-based compound semiconductor, or may further include an InP-based compound semiconductor.

[0093] The first compound semiconductor layer may include a first conductivity type (e.g., n-type) compound semiconductor, and the second compound semiconductor layer may include a second conductivity type (e.g., p-type) compound semiconductor different from the first conductivity type. The first compound semiconductor layer and the second compound semiconductor layer are also referred to as a first clad layer and a second clad layer. Preferably, a current constriction structure is formed between the second electrode and the second compound semiconductor layer. The first compound semiconductor layer and the second compound semiconductor layer may be a layer having a single structure, a layer having a multilayer structure, or a layer having a superlattice structure. In addition, these layers may be layers including a composition gradient layer and a concentration gradient layer.

[0094] In addition, in the above-mentioned light-emitting elements according to the first aspect to the second aspect of the present disclosure, including preferred embodiments and configurations, for the materials constituting the various compound semiconductor layers located between the active layer and the first light reflecting layer, it is preferred that there is no modulation of the refractive index greater than or equal to 10% (there is no refractive index difference greater than or equal to 10% based on the average refractive index of the laminated structure), as a result, the occurrence of disturbances in the light field in the resonator can be suppressed.

[0095] In order to obtain a current confinement structure, an insulating material (e.g., SiO X 、SiN X 、AlO X ) may be formed between the second electrode and the second compound semiconductor layer, or alternatively, a mesa structure may be formed by etching the second compound semiconductor layer using an RIE method or the like, or alternatively, a current confinement region may be formed by partially oxidizing a portion of the laminated second compound semiconductor layer from a lateral direction, or a region with reduced conductivity may be formed by implanting impurity ions into the second compound semiconductor layer, or they may be appropriately combined. However, the second electrode needs to be electrically connected to a portion of the second compound semiconductor layer through which current flows due to current confinement.

[0096] In an embodiment in which the protrusion is formed on a substrate, the laminated structure is formed on the second surface of the substrate. Here, the second surface of the substrate faces the first surface of the compound semiconductor layer. Then, a protrusion is formed on the first surface of the substrate facing the second surface of the substrate. Examples of substrates include conductive substrates, semiconductor substrates, insulating substrates, specifically, GaN substrates, sapphire substrates, GaAs substrates, SiC substrates, alumina substrates, ZnS substrates, ZnO substrates, AlN substrates, LiMgO substrates, LiGaO2 substrates, MgAl2O4 substrates, InP substrates, Si substrates, and substrates in which a base layer or a buffer layer is formed on the surface (main surface) of these substrates. In the case where the laminated structure includes a GaN-based compound semiconductor, it is preferred to use a GaN substrate as the substrate because the crystal defect density of the GaN substrate is low. It is known that the characteristics of the GaN substrate change to polarity / non-polarity / semi-polarity according to the growth surface, but any main surface (second surface) of the GaN substrate can be used to form a compound semiconductor layer. In addition, regarding the main surface of the GaN substrate, depending on the crystal structure (for example, cubic type, hexagonal type, etc.), a crystal orientation plane with a name such as the so-called A plane, B plane, C plane, R plane, M plane, N plane, or S plane, a plane in which these planes are offset in a specific direction, etc. may be used. Alternatively, an embodiment may be adopted in which the substrate includes a GaN substrate having a {20-21} plane as a semipolar plane as a main surface (a GaN substrate whose main surface is a surface in which the c plane is inclined by about 75 degrees in the m-axis direction).

[0097] Examples of methods for forming various compound semiconductor layers constituting the light-emitting element include metal organic chemical vapor deposition (metal organic chemical vapor deposition (MOCVD), metal organic vapor phase epitaxy (MOVPE), or molecular beam epitaxy (MBE), hydride vapor deposition (HVPE) in which halogen facilitates transport or reaction, atomic layer deposition (ALD), migration enhanced epitaxy (MEE), plasma assisted physical vapor deposition (PPD), and the like, but the method is not limited thereto. Here, in the case where the laminated structure includes a GaN-based compound semiconductor, examples of organic gallium source gas in the MOCVD method include trimethyl gallium (TMG) gas and triethyl gallium (TEG) gas, and examples of nitrogen source gas include ammonia gas and hydrazine gas. When forming a GaN-based compound semiconductor layer having an n-type conductivity type, for example, it is only necessary to add silicon (Si) as an n-type impurity (n-type dopant). ), and when forming a GaN-based compound semiconductor layer having a p-type conductivity type, for example, it is only necessary to add magnesium (Mg) as a p-type impurity (p-type dopant). In the case of containing aluminum (Al) or indium (In) as a constituent atom of the GaN-based compound semiconductor layer, it is only necessary to use trimethylaluminum (TMA) gas as an Al source, and it is only necessary to use trimethylindium (TMI) gas as an In source. In addition, it is only necessary to use monosilane gas (SiH4 gas) as an Si source, and it is only necessary to use biscyclopentadienyl magnesium gas, methylcyclopentadienyl magnesium or biscyclopentadienyl magnesium (Cp2Mg) as a Mg source. It is noted that, in addition to Si, examples of n-type impurities (n-type dopants) include Ge, Se, Sn, C, Te, S, O, Pd and Po, and in addition to Mg, examples of p-type impurities (p-type dopants) include Zn, Cd, Be, Ca, Ba, C, Hg and Sr.

[0098] The thickness of the substrate can be reduced, or the substrate can be removed to expose the first surface of the first compound semiconductor layer by wet etching using an alkaline aqueous solution (such as an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution), an aqueous ammonia solution + a hydrogen peroxide solution, a sulfuric acid solution + a hydrogen peroxide solution, a hydrochloric acid solution + a hydrogen peroxide solution, a phosphoric acid solution + a hydrogen peroxide solution, or the like, a chemical mechanical polishing method (CMP method), a mechanical polishing method, a dry etching method, a stripping method using a laser, or a combination thereof.

[0099] As described above, the laminated structure may be configured to be formed on a polar face of a GaN substrate. Alternatively, the laminated structure may be configured to be formed on a primary surface including a semipolar face or a nonpolar face (nonpolar face) of a GaN substrate, and in this case, the angle formed by the plane orientation of the primary surface and the c-axis may be made greater than or equal to 45 degrees and less than or equal to 80 degrees, and further, the primary surface of the GaN substrate may include a {20-21} face. In the hexagonal system, for example, for convenience, in this specification, the symbols of the crystal faces exemplified below are

[0100]

[0101]

[0102] Written as {hk-il} face and {h-kil} face.

[0103] Below, we will refer to Fig. 27 (a) to (e) describe the polar plane, nonpolar plane, and semipolar plane in the nitride semiconductor crystal. Fig. 27 (a) is a schematic diagram illustrating the crystal structure of a hexagonal nitride semiconductor. Fig. 27 (b) is a schematic diagram illustrating an m-plane which is a nonpolar plane ({1-100} plane), and the m-plane illustrated in gray is a plane perpendicular to the m-axis direction. Fig. 27 (c) is a schematic diagram illustrating an a-plane which is a nonpolar plane ({11-20} plane), and the a-plane illustrated in gray is a plane perpendicular to the a-axis direction. Fig. 27 (d) is a schematic diagram illustrating a {20-21} plane as a semipolar plane. The [20-21] direction perpendicular to the {20-21} plane illustrated in gray is inclined 75 degrees from the c-axis to the m-axis. Fig. 27 (e) is a schematic diagram illustrating a {11-22} plane as a semipolar plane. The [11-22] direction perpendicular to the {11-22} plane illustrated in gray is tilted 59 degrees from the c-axis to the a-axis. Table 1 below indicates the angle formed by the plane orientation of various crystal planes and the c-axis. The planes represented by {11-2n} planes, {1-101} planes, {1-102} planes, and {1-103} planes such as {11-21} planes, {11-22} planes, and {11-24} planes are semipolar planes.

[0104]

[0105] Face Orientation Angle with c-axis (degrees) {1-100} 90.0 {11-20} 90.0 {20-21} 75.1 {11-21} 72.9 {1-101} 62.0 {11-22} 58.4 {1-102} 43.2 {1-103} 32.0

[0106] It is also possible to configure a surface emitting laser element in which the second light reflecting layer is supported by a supporting substrate and the laser beam is emitted through the first light reflecting layer. The supporting substrate only needs to include, for example, various substrates exemplified as the above-mentioned substrates, or alternatively, it may also include an insulating substrate containing AlN, etc., a semiconductor substrate containing Si, SiC, Ge, etc., or a metal substrate or an alloy substrate, but it is preferred to use a substrate having conductivity, or alternatively, it is preferred to use a metal substrate or an alloy substrate from the perspective of mechanical properties, elastic deformation, plastic deformation, heat dissipation, etc. For the thickness of the supporting substrate, for example, 0.05 mm to 1 mm can be exemplified. As a method for fixing the second light reflecting layer to the supporting substrate, known methods such as a solder bonding 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, and from the perspective of ensuring conductivity, it is desirable to adopt a solder bonding method or a room temperature bonding method. For example, in the case of using a silicon semiconductor substrate as a conductive substrate as a supporting substrate, it is desirable to adopt a method that can be bonded at a low temperature of less than or equal to 400°C to suppress curling due to differences in thermal expansion coefficients. In the case of using a GaN substrate as a support substrate, the bonding temperature may be higher than or equal to 400°C.

[0107] The first compound semiconductor layer is electrically connected to the first electrode. That is, the first electrode is electrically connected to the first compound semiconductor layer via the substrate, or alternatively, the first electrode is formed on the first compound semiconductor layer. In addition, the second compound semiconductor layer is electrically connected to the second electrode, and the second light reflecting layer is formed on the second electrode. An embodiment in which the first electrode includes a metal or an alloy can be adopted, and an embodiment in which the second electrode includes a transparent conductive material can be adopted. By forming the second electrode from a transparent conductive material, the current can be extended in the lateral direction (the in-plane direction of the second compound semiconductor layer), and the current can be efficiently supplied to the element region. The second electrode is formed on the second surface of the second compound semiconductor layer. Here, "element region" refers to a region in which a limiting current is injected, or alternatively, a region in which light is limited due to a refractive index difference, etc., or alternatively, a region in which laser oscillation occurs in a region sandwiched between the first light reflecting layer and the second light reflecting layer, or alternatively, a region in which a region in which a laser oscillation is actually contributed to in a region sandwiched between the first light reflecting layer and the second light reflecting layer.

[0108] The first electrode only needs to be formed on the first surface of the substrate facing the second surface of the substrate. It is desirable that the first electrode has a single-layer configuration or a multilayer configuration, and the multilayer configuration includes at least one metal (including alloy) selected from the group consisting of, for example, gold (Au), silver (Ag), palladium (Pd), platinum (Pt), nickel (Ni), titanium (Ti), vanadium (V), tungsten (W), chromium (Cr), aluminum (Al), copper (Cu), zinc (Zn), tin (Sn) and indium (In), specifically, for example, Ti / Au, Ti / Al, Ti / Al / Au, Ti / Pt / Au, Ni / Au / Pt, Ni / Pt, Pd / Pt and Ag / Pd. It is noted that the layer before " / " in the multilayer configuration is positioned closer to the active layer side. For the following description, the same applies. The first electrode can be formed by a PVD method (for example, a vacuum vapor deposition method, a sputtering method, etc.).

[0109] The second electrode may include a transparent conductive material. As the transparent conductive material constituting the second electrode, examples may include an indium-based transparent conductive material [specifically, for example, indium tin oxide (ITO, including Sn-doped In2O3, crystalline ITO and amorphous ITO), indium-zinc oxide (IZO), indium-gallium oxide (IGO), indium-doped gallium-zinc oxide (IGZO, In-GaZnO4), IFO (F-doped In2O3), ITiO (Ti-doped In2O3), InSn, InSnZnO], a tin-based transparent conductive material [specifically, for example, tin oxide (SnO2), ATO (Sb-doped SnO2), FTO (F-doped SnO2)], a zinc-based transparent conductive material [specifically, for example, zinc oxide (ZnO, including Al-doped ZnO (AZO) and B-doped ZnO), gallium-doped zinc oxide (GZO), AlMgZnO (aluminum oxide and magnesium oxide doped zinc oxide)] and NiO. Alternatively, examples of the second electrode include a transparent conductive film containing gallium oxide, titanium oxide, niobium oxide, antimony oxide, nickel oxide, etc. as a base layer, and also include transparent conductive materials such as spinel oxides and oxides having a YbFe2O4 structure. However, although it depends on the arrangement state of the second light reflecting layer and the second electrode, as a material constituting the second electrode, it is not limited to transparent conductive materials, and metals such as palladium (Pd), platinum (Pt), nickel (Ni), gold (Au), cobalt (Co) or rhodium (Rh) can also be used. The second electrode only needs to include at least one of these materials. The second electrode can be formed by a PVD method (for example, a vacuum vapor deposition method, a sputtering method, etc.). Alternatively, a low-resistance semiconductor layer can also be used as a transparent electrode layer, and in this case, specifically, an n-type GaN-based compound semiconductor layer can also be used. In addition, in the case where the layer adjacent to the n-type GaN-based compound semiconductor layer is p-type, the resistance at the interface can be reduced by joining the two layers via a tunnel junction. By forming the second electrode from a transparent conductive material, current can be spread in the lateral direction (in-plane direction of the second compound semiconductor layer), and current can be efficiently supplied to a current injection region (described later).

[0110] The pad electrode may be disposed on the first electrode or the second electrode to be electrically connected to an external electrode or circuit. The pad electrode preferably has a single-layer configuration or a multilayer configuration, including at least one metal selected from the group consisting of titanium (Ti), aluminum (Al), platinum (Pt), gold (Au), nickel (Ni) and palladium (Pd). Alternatively, the pad electrode may also have a multilayer configuration exemplified by a Ti / Pt / Au multilayer configuration, a Ti / Au multilayer configuration, a Ti / Pd / Au multilayer configuration, a Ti / Pd / Au multilayer configuration, a Ti / Ni / Au multilayer configuration or a Ti / Ni / Au / Cr / Au multilayer configuration. In the case where the first electrode includes an Ag layer or an Ag / Pd layer, it is preferred that a covering metal layer including, for example, Ni / TiW / Pd / TiW / Ni is formed on the surface of the first electrode, and a pad electrode including, for example, a Ti / Ni / Au multilayer configuration or a Ti / Ni / Au / Cr / Au multilayer configuration is formed on the covering metal layer.

[0111] The light reflecting layer (distributed Bragg reflector layer (DBR layer)) constituting the first light reflecting layer and the second light reflecting layer includes, for example, a semiconductor multilayer film (for example, an AlInGaN film) or a dielectric multilayer film. Examples of dielectric materials include oxides, nitrides (for example, SiN, etc.) of Si, Mg, Al, Hf, Nb, Zr, Sc, Ta, Ga, Zn, Y, B, Ti, etc. X 、AlN X 、AlGaN X 、GaN X , BN X etc.), fluoride, etc. Specifically, SiO X 、TiO X 、NbO X 、ZrO X 、TaO X 、ZnO X 、AlO X , HfO X 、SiN X 、AlN X Then, the light reflecting layer can be obtained by alternately laminating two or more dielectric films including dielectric materials having different refractive indexes among these dielectric materials. For example, a dielectric material such as SiO X / SIN Y 、SiO X / TaO X 、SiO X / NbO Y 、SiO X / ZrO Y and SiO X / AlN YA dielectric multilayer film such as is preferred. In order to obtain the desired light reflectivity, it is only necessary to appropriately select the material constituting each dielectric film, the film thickness, the number of laminated layers, etc. The thickness of each dielectric film can be appropriately adjusted according to the material used, etc., and the thickness is determined by the oscillation wavelength (emission wavelength) λ0 of the material used and the refractive index n' at the oscillation wavelength λ0. Specifically, it is preferred to set the a value to an odd multiple or approximately an odd multiple of λ0 / (4n'). For example, in a case where the light reflecting layer includes SiO X / NbO Y In the case of a light emitting element having an oscillation wavelength λ0 of 410 nm, an example may be about 40 nm to 70 nm. As an example, the number of laminated layers may be greater than or equal to 2, preferably about 5 to 20. As the thickness of the entire light reflecting layer, for example, an example may be about 0.6 μm to 1.7 μm. In addition, it is desirable that the light reflectivity of the light reflecting layer is greater than or equal to 95%.

[0112] The light reflecting layer can be formed based on a known method, specifically, examples of the method include: PVD methods such as vacuum vapor deposition, sputtering, reactive sputtering, ECR plasma sputtering, magnetron sputtering, ion beam assisted vapor deposition, ion plating and laser ablation; various CVD methods; coating methods such as spraying, spin coating and dipping; a method combining two or more of these methods; a method combining these methods with all or part of pretreatment, radiation with inert gas (Ar, He, Xe, etc.) or plasma, radiation with oxygen, ozone gas and plasma, oxidation treatment (heat treatment) and exposure treatment.

[0113] The size and shape of the light reflection layer are not particularly limited as long as the light reflection layer covers the current injection region or the element region. For the shape of the boundary between the element region, the first light reflection layer, the second light reflection layer, the current injection region and the current non-injection / internal region, the shape of the boundary between the current non-injection / internal region and the current non-injection / external region, and the plane shape of the opening provided in the element region or the current limiting region, specific examples include circular, elliptical, rectangular and polygonal (triangular, quadrilateral, hexagonal, etc.). In addition, for the plane shape of the first electrode, an annular shape can be mentioned. It is expected that the plane shape of the opening provided in the element region, the first light reflection layer, the second light reflection layer and the current limiting layer, the plane shape of the inner ring of the annular first electrode, the shape of the boundary between the current injection region and the current non-injection / internal region, and the shape of the boundary between the current non-injection / internal region and the current non-injection / external region are similar. In the case where the boundary shape between the current injection region and the current non-injection / internal region is circular, the diameter is preferably about 5μm to 100μm. Subsequently, the current injection region, the current non-injection / internal region and the current non-injection / external region will be described.

[0114] The side or exposed surface of the laminated structure may be covered with a coating (insulating film). The formation of the coating (insulating film) may be performed based on a known method. The refractive index of the material constituting the coating (insulating film) is preferably smaller than the refractive index of the material constituting the laminated structure. As the insulating material constituting the coating (insulating film), an SiO-based insulating material containing SiO2 may be exemplified. X Materials, based on SiN X Materials based on SiO Y N Z Materials, TaO X 、ZrO X 、AlN X 、AlO X and GaO X , or alternatively, an organic material such as a polyimide-based resin can also be mentioned. As a method for forming a coating (insulating film), for example, a PVD method or a CVD method such as a vacuum vapor deposition method or a sputtering method can be mentioned, and formation can also be performed based on a coating method.

[0115] In the light emitting elements according to the first aspect to the second aspect of the present disclosure including the above-mentioned various preferred embodiments, when the resonator length is L OR When L OR ≥1×10 -6 m.

[0116] [Example 1]

[0117] Example 1 relates to a light-emitting element of the present disclosure and a method for manufacturing a light-emitting element according to the first aspect of the present disclosure. More specifically, the light-emitting element of Example 1 or Examples 2 to 12 described later includes a surface-emitting laser element (vertical cavity surface-emitting laser (VCSEL)) that emits a laser beam from the top surface of the second compound semiconductor layer through the second light-reflecting layer. Figure 1 A schematic partial end view of a light emitting element of Example 1 is illustrated.

[0118] A light emitting element of Example 1 or light emitting elements of Examples 2 to 12 described later include:

[0119] A laminated structure 20, in which a first compound semiconductor layer 21, an active layer (light-emitting layer) 23 and a second compound semiconductor layer 22 are laminated, the first compound semiconductor layer 21 includes a first surface 21a and a second surface 21b facing the first surface 21a, the active layer 23 faces the second surface 21b of the first compound semiconductor layer 21, and the second compound semiconductor layer 22 includes a first surface 22a facing the active layer 23 and a second surface 22b facing the first surface 22a;

[0120] a first electrode 31 electrically connected to the first compound semiconductor layer 21 ; and

[0121] The second electrode 32 and the second light reflecting layer 42 are formed on the second surface 22 b of the second compound semiconductor layer 22 .

[0122] Then, in the light-emitting element of Example 1,

[0123] A protrusion 43 is formed on the first surface side of the first compound semiconductor layer 21,

[0124] A smoothing layer 44 is formed at least on the protrusion 43,

[0125] The protrusion 43 and the smooth layer 44 constitute a concave mirror portion.

[0126] forming a first light reflecting layer 41 on at least a portion of the smoothing layer 44, and

[0127] The second light reflecting layer 42 has a flat shape.

[0128] Specifically, the protrusion 43 is formed on the first surface 11a of the substrate 11. The laminated structure 20 is provided on the second surface 11b of the substrate 11. The smooth layer 44 is formed on the first surface 11a of the substrate including the top of the protrusion 43. The first light reflecting layer 41 is formed on the smooth layer 44. Here, in Example 1, the substrate 11 includes a compound semiconductor substrate, specifically, a GaN substrate whose main surface is surface C, i.e., a {0001} plane as a polar plane. The laminated structure 20 includes a GaN-based compound semiconductor. The first compound semiconductor layer 21 has a first conductivity type (specifically, n-type), and the second compound semiconductor layer 22 has a second conductivity type (specifically, p-type) different from the first conductivity type. The resonator is composed of a region from the inner surface 41a of the first light reflecting layer 41 to a certain depth, a smooth layer 44, a substrate 11 including a protrusion 43, a laminated structure 20 (a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22), a second electrode 32, and a region from the second surface 22b of the second compound semiconductor layer 22 to a certain depth of the second light reflecting layer 42. Here, when the resonator length is L OR When L OR ≥1×10 -6 m(1μm).

[0129] The value of the surface roughness Ra1 of the smooth layer 44 at the interface 44A between the smooth layer 44 and the first light reflecting layer 41 is smaller than the value of the surface roughness Ra2 of the protrusion 43 at the interface 43A between the protrusion 43 and the smooth layer 44. The value of the surface roughness Ra1 is less than or equal to 1.0 nm. In addition, the average thickness T of the smooth layer 44 at the top of the protrusion 43 is C The average thickness T of the smooth layer 44 at the edge of the protrusion 43 is P Thin. Specifically, T P / T C The value satisfies 0.01≤T P / T C ≤0.5, T C The value satisfies 1×10 -8 m to 2×10 -6 m, and more specifically,

[0130] T C =0.2μm

[0131] T P / T C =0.05.

[0132] The curvature radius of the smoothing layer 44 is 1×10 -5 m to 1×10 -3 m, and specifically, 100 μm.

[0133] The material constituting the smoothing layer 44 is at least one material selected from the group consisting of a dielectric material, a spin-on glass-based material, a low-melting-point glass material, a semiconductor material, and a resin. In Example 1, specifically, as the material constituting the smoothing layer 44, for example, a dielectric material, more specifically, Ta2O5 is used.

[0134] Then, in the light-emitting element of Example 1, the figure drawn by the inner surface 41a of the first light reflecting layer 41 (the effective area 41b of the first light reflecting layer 41) when the first light reflecting layer 41 is cut by a virtual plane including the lamination direction of the laminated structure 20 (a virtual plane including the Z axis) is a portion of a circle or a portion of a parabola. However, the shape (the figure of the cross-sectional shape) of the first light reflecting layer 41 located outside the effective area 41b is not necessarily a portion of a circle or a portion of a parabola. The first light reflecting layer 41 extends above a portion of the first surface 11a of the substrate 11, and the shape (the figure of the cross-sectional shape) of the portion is flat. The first light reflecting layer 41 and the second light reflecting layer 42 include a multilayer light reflecting film. The planar shape of the outer edge of the protrusion 43 is circular.

[0135] In addition, when the radius of the effective area 41b of the first light reflecting layer 41 is r′ DBR And the radius of curvature is R DBR When R DBR ≤1×10 -3 m. Specifically, examples may be:

[0136] L OR =50μm,

[0137] R DBR =70μm,

[0138] r' DBR =25μm,

[0139] However, the present invention is not limited thereto. In addition, as the oscillation wavelength λ0 of the main light emitted from the active layer 23, λ0=445 nm can be exemplified.

[0140] Here, when the distance from the center of gravity of the active layer 23 to the inner surface 41a of the first light reflecting layer 41 is T0 and when the length of the portion of the resonator including the inner surface 41a of the first light reflecting layer 41 and the first surface 21a of the first compound semiconductor layer 21 is L DBR When , the ideal parabolic function x = f (z) can be expressed as

[0141] x=z 2 / t0,

[0142] L DBR =r' DBR2 / 2T0;

[0143] However, it goes without saying that when the figure drawn by the inner surface 41a is a portion of a parabola, the parabola may deviate from such an ideal parabola.

[0144] The value of the thermal conductivity of the laminated structure 20 is higher than the value of the thermal conductivity of the first light reflecting layer 41. The value of the thermal conductivity of the dielectric material constituting the first light reflecting layer 41 is generally about 10 W / (m·K), or equal to or less than this value. On the other hand, the value of the thermal conductivity of the GaN-based compound semiconductor constituting the laminated structure 20 is about 50 W / (m·K) to about 100 W / (m·K).

[0145] The first compound semiconductor layer 21 includes an n-GaN layer; the active layer 23 includes an In 0.04 Ga 0.96 N layer (barrier layer) and In 0.16 Ga 0.84 The first electrode 31 is formed on the first surface 11a of the substrate 11 and is electrically connected to the first compound semiconductor layer 21 via the substrate 11. On the other hand, the second electrode 32 is formed on the second compound semiconductor layer 22, and the second light reflection layer 42 is formed on the second electrode 32. The second light reflection layer 42 on the second electrode 32 has a flat shape. The first electrode 31 includes Ti / Pt / Au, and the second electrode 32 includes a transparent conductive material, specifically, ITO. On the edge of the first electrode 31, a pad electrode (not shown) for electrically connecting to an external electrode or circuit is formed or connected, and the pad electrode includes, for example, Ti / Pt / Au or V / Pt / Au. On the edge of the second electrode 32, a pad electrode 33 for electrically connecting to an external electrode or circuit is formed or connected, and the pad electrode 33 includes, for example, Pd / Ti / Pt / Au, Ti / Pd / Au or Ti / Ni / Au. The first light reflecting layer 41 and the second light reflecting layer 42 include a laminated structure of a Ta2O5 layer and a SiO2 layer (the total number of laminated layers of the dielectric film: 20 layers). Although the first light reflecting layer 41 and the second light reflecting layer 42 have a multilayer structure as described above, they are represented by one layer in order to simplify the drawings. The planar shape of each 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 limiting layer) 34 is circular. As will be described later, the current limiting region (the current injection region 61A and the current non-injection region 61B) is defined by the insulating layer 34 including the opening 34A, and the current injection region 61A is defined by the opening 34A.

[0146] In the following, reference Figure 2 , Figure 3, Figure 4 , Figure 5 and Figure 6 A method for manufacturing the light emitting element of Example 1 is described.

[0147] [STEP-100]

[0148] First, on the surface (second surface 11b) of the substrate 11, a laminated structure 20 is formed, in which a first compound semiconductor layer 21, an active layer 23, and a second compound semiconductor layer 22 are laminated, the first compound semiconductor layer 21 includes a first surface 21a and a second surface 21b facing the first surface 21a, the active layer 23 faces the second surface 21b of the first compound semiconductor layer 21, and the second compound semiconductor layer 22 includes a first surface 22a facing the active layer 23 and a second surface 22b facing the first surface 22a. Specifically, based on the MOCVD method, the first compound semiconductor layer 21, the active layer 23, and the second compound semiconductor layer 22 including n-GaN are formed on the exposed second surface 11b of the substrate 11, thereby obtaining the laminated structure 20 (see Figure 2 ).

[0149] [STEP-110]

[0150] Next, based on a film forming method such as a CVD method, a sputtering method, or a vacuum vapor deposition method, and a combination of wet etching or dry etching, an insulating layer (current confinement layer) 34 including an opening 34A and containing SiO2 is formed on the second surface 22b of the second compound semiconductor layer 22. A current confinement region (a current injection region 61A and a current non-injection region 61B) is defined by the insulating layer 34 including the opening 34A. That is, the current injection region 61A is defined by the opening 34A.

[0151] In order to obtain a current confinement region, an insulating material (e.g., SiO X 、SiN X 、AlO X ) may be formed between the second electrode 32 and the second compound semiconductor layer 22, or alternatively, a mesa structure may be formed by etching the second compound semiconductor layer 22 using an RIE method or the like, or alternatively, a current confinement region may be formed by partially oxidizing a portion of the laminated second compound semiconductor layer 22 from a lateral direction, or a region with reduced conductivity may be formed by implanting impurity ions into the second compound semiconductor layer 22, or a combination thereof may be performed as needed. However, the second electrode 32 needs to be electrically connected to the portion of the second compound semiconductor layer 22, causing current to flow through the portion of the second compound semiconductor layer 22 due to current confinement.

[0152] [STEP-120]

[0153] Thereafter, the second electrode 32 and the second light reflecting layer 42 are formed on the second surface of the second compound semiconductor layer 22. Specifically, for example, based on the lift-off method, the second electrode 32 is formed over the insulating layer 34 from the second surface 22b of the second compound semiconductor layer 22 exposed on the bottom surface of the opening 34A (current injection region 61A), and further, the pad electrode 33 is formed based on a combination of a film forming method such as a sputtering method or a vacuum vapor deposition method and a patterning method such as wet etching or dry etching. Next, based on a combination of a film forming method such as a sputtering method or a vacuum vapor deposition method and a patterning method such as wet etching or dry etching, the second light reflecting layer 42 is formed over the pad electrode 33 from the second electrode 32 (see Figure 3 ). The second light reflecting layer 42 on the second electrode 32 has a flat shape.

[0154] [STEP-130]

[0155] Next, the protrusion 43 is formed on the first surface side of the first compound semiconductor layer 21. Specifically, first, the substrate 11 is thinned to a desired thickness from the first surface 11a side. Then, a resist layer is formed on the first surface 11a of the substrate 11, and the resist layer is patterned to leave the resist layer on the substrate 11 on which the protrusion 43 is to be formed. Then, a heat treatment is performed on the resist layer to form a protrusion in the resist layer. Next, the resist layer and the substrate 11 are etched back based on the RIE method. In this way, as Figure 4 As shown in the figure, the protrusion 43 may be formed on the first surface 11a of the substrate 11. The protrusion 43 has a circular shape.

[0156] [STEP-140]

[0157] Thereafter, a smoothing layer 44 is formed at least on the protrusion 43 (see Figure 5 Specifically, based on the sputtering method, the smoothing layer 44 is formed on the entire surface of the first surface 11 a of the substrate 11 including the protrusion 43 .

[0158] [STEP-150]

[0159] Next, the surface of the smoothing layer 44 is smoothed (see Figure 6 ). Specifically, the surface of the smoothing layer 44 is smoothed based on wet etching. More specifically, the surface of the smoothing layer 44 is smoothed based on a CMP method using colloidal silica as a polishing liquid. The surface roughness of the surface of the smoothing layer 44 before and after the smoothing is as follows.

[0160] Before smoothing: Ra = 0.36nm

[0161] After smoothing: Ra1 = 0.14 nm

[0162] [STEP-160]

[0163] Thereafter, the first light reflecting layer 41 is formed on at least a portion of the smoothing layer 44, and the first electrode 31 electrically connected to the first compound semiconductor layer 21 is formed. Specifically, based on a combination of a film forming method such as sputtering or vacuum vapor deposition and a patterning method such as wet etching or dry etching, the first light reflecting layer 41 including a dielectric multilayer film is formed on the smoothing layer 44. The planar shape of the outer edge of the first light reflecting layer 41 remaining on the first surface 11a of the substrate 11 is circular. Thereafter, based on a combination of a film forming method such as sputtering or vacuum vapor deposition and a patterning method such as wet etching or dry etching, the first electrode 31 is formed on the first surface 11a of the substrate 11. In this way, it is possible to obtain Figure 1 In addition, the light emitting element is then separated by performing so-called element separation, and the side surfaces and exposed surfaces of the laminated structure 20 are covered with a coating (not shown) including an insulating material such as SiO2, for example. Then, the light emitting element of Example 1 can be completed by packaging or sealing.

[0164] In the light-emitting element of Example 1 or the light-emitting element obtained by the method for manufacturing the light-emitting element of Example 1, the surface of the smooth layer as the base of the first light-reflecting layer is smooth, so that the first light-reflecting layer formed on the smooth layer is also smooth. Therefore, since the scattering of light by the first light-reflecting layer can be suppressed, the threshold of the light-emitting element can be lowered and the luminous efficiency can be improved.

[0165] In addition, in the light-emitting element of Example 1, since the first light reflecting layer is formed above the protrusion, the light is diffracted and diffused starting from the active layer, and the light incident on the first light reflecting layer can be reliably reflected toward the active layer and focused on the active layer. Therefore, the increase in diffraction loss can be avoided, and laser oscillation can be reliably performed. In addition, since the resonator can be longer, the problem of thermal saturation can be avoided. Here, "thermal saturation" is a phenomenon in which the light output is saturated due to self-heating when the surface-emitting laser element is driven. The material used for the light reflecting layer (for example, a material such as SiO2 or Ta2O5) has a thermal conductivity value lower than the thermal conductivity value of the GaN-based compound semiconductor. Therefore, increasing the thickness of the GaN-based compound semiconductor layer results in suppressing thermal saturation. However, when the thickness of the GaN-based compound semiconductor layer increases, the resonator length L OR The length of the resonator becomes longer, so that the longitudinal mode may become multi-mode, but in the light-emitting element of Example 1, a single longitudinal mode can be obtained even when the resonator length is long. In addition, since the resonator length LOR The length can be extended, so the tolerance of the manufacturing process of the light emitting element is increased, and as a result, the yield can be improved. The same applies to the light emitting elements of various examples described below.

[0166] Instead of the CMP method, the surface of the smoothing layer 44 may be smoothed based on an immersion method. In this case, for example, since the smoothing layer 44 includes Ta2O5, in the immersion method, only HF is required to be used as an etching solution. In addition, the smoothing layer 44 may also include a spin-on glass-based material or a low-melting-point glass material, and in this case, the smoothing layer 44 may be smoothed based on a CMP method using colloidal silica as a polishing agent, and the smoothing layer 44 may be smoothed based on an immersion method using HF as an etching solution. In addition, the material constituting the smoothing layer 44 may also be a semiconductor material, specifically, GaN. In this case, the smoothing layer 44 may be smoothed based on a CMP method using colloidal silica as a polishing agent, and the smoothing layer 44 may be smoothed based on an immersion method using TMAH as an etching solution. In addition, the material constituting the smoothing layer 44 may include a resin, particularly an epoxy-based resin, and the smoothing layer 44 may be smoothed based on a CMP method, and the smoothing layer 44 may be smoothed based on an immersion method using a halogenated hydrocarbon as an etching solution. However, depending on the resin used, smoothing may not be necessary.

[0167] Furthermore, the material constituting the smoothing layer 44 may include, for example, Ta 2 O 5 , and a smoothing process is performed on the surface of the smoothing layer 44 based on dry etching, specifically, based on the RIE method (Reactive Ion Etching method).

[0168] Furthermore, the laminated structure 20 may include a GaAs-based compound semiconductor instead of a GaN-based compound semiconductor, and in this case, it is only necessary to use a GaAs substrate as the substrate 11. Then, in this case, the smoothing treatment of the smoothing layer 44 may be performed based on a CMP method using colloidal silica as a polishing agent, and the smoothing treatment of the smoothing layer 44 may be performed based on an immersion method using a phosphoric acid / hydrogen peroxide solution as an etching solution. Alternatively, the laminated structure 20 may include an InP-based compound semiconductor, and in this case, it is only necessary to use an InP substrate as the substrate 11. Then, in this case, the smoothing treatment of the smoothing layer 44 may be performed based on a CMP method using colloidal silica as a polishing agent, and the smoothing treatment of the smoothing layer 44 may be performed based on an immersion method using hydrochloric acid as an etching solution.

[0169] [Example 2]

[0170] Example 2 is a variation of Example 1. Figure 7A schematic partial end view of a light emitting element of Example 2 is illustrated. In Example 1, the protrusion 43 is formed on the first surface 11 a of the substrate 11 . On the other hand, in Example 2, the protrusion 45 is formed on the first compound semiconductor layer 21 .

[0171] In such a light-emitting element of Example 2, in a step similar to [Step-130] in the light-emitting element manufacturing method of Example 1, the substrate 11 is removed from the first surface 11a side to expose the first compound semiconductor layer 21, a resist layer is formed on the first surface 21a of the first compound semiconductor layer 21, and the resist layer is patterned to leave the resist layer on the first compound semiconductor layer 21 on which the protrusion 45 is to be formed. Then, heat treatment is performed on the resist layer to form a protrusion in the resist layer. Next, based on the RIE method, the resist layer and the first compound semiconductor layer 21 are etched back. In this way, it is finally possible to obtain Figure 7 The light-emitting element of Example 2 is illustrated in FIG.

[0172] Except for the above points, the configuration and structure of the light emitting element of Example 2 may be similar to those of the light emitting element of Example 1, and thus a detailed description thereof will be omitted.

[0173] [Example 3]

[0174] Example 3 is also a variation of Example 1. Figure 8 and Fig. 9 2 is a schematic partial end view of a light emitting element of Example 3. In Example 3, a protrusion 46 is formed on the first surface 11a of the substrate 11 based on a material different from that of the substrate 11 (see Figure 8 Alternatively, the protrusion 46 is formed on the exposed surface (first surface 21a) of the first compound semiconductor layer 21 based on a material different from that of the first compound semiconductor layer 21 (see Fig. 9 Here, examples of the material constituting the protrusion 46 include a transparent dielectric material such as TiO 2 , Ta 2 O 5 , or SiO 2 , a silicone-based resin, and an epoxy-based resin.

[0175] In the light-emitting element of Example 3, in a step similar to [Step-130] of Example 1, the substrate 11 is thinned, mirror-finishing is performed, and then the protrusion 46 is formed on the exposed surface (first surface 11a) of the substrate 11. Alternatively, the substrate 11 is removed, mirror-finishing is performed on the first surface 21a of the exposed first compound semiconductor layer 21, and then the protrusion 46 is formed on the exposed surface (first surface 21a) of the first compound semiconductor layer 21. Specifically, for example, a TiO2 layer or a Ta2O5 layer is formed on the exposed surface (first surface 11a) of the substrate 11, and then a patterned resist layer is formed on the TiO2 layer or the Ta2O5 layer on which the protrusion 46 is formed, and the resist layer is heated and reflowed to obtain a resist pattern. The resist pattern is given a shape that is the same as (or similar to) the shape of the protrusion 46. Then, by etching back the resist pattern and the TiO2 layer or the Ta2O5 layer, a protrusion 46 can be formed on the exposed surface (first surface 11a) of the substrate 11. In this way, a Figure 8 The light-emitting element of Example 3 is illustrated in FIG.

[0176] Except for the above points, the configuration and structure of the light emitting element of Example 3 may be similar to those of the light emitting element of Example 1, and thus a detailed description thereof will be omitted.

[0177] [Example 4]

[0178] Example 4 relates to a method for manufacturing a light emitting element according to the second aspect of the present disclosure. Fig. 10A and Fig. 10B A schematic partial end view of the light emitting element of Example 4 is illustrated in FIG. In the light emitting element of Example 4,

[0179] A protrusion 47 is formed on the first surface side of the first compound semiconductor layer 21,

[0180] The protrusion 47 constitutes a concave mirror portion.

[0181] The first light reflecting layer 41 is formed at least on the protrusion 47, and

[0182] The second light reflecting layer 42 has a flat shape.

[0183] Here, the value of the surface roughness Ra2 of the protrusion 47 at the interface between the protrusion 47 and the first light reflecting layer 41 is equal to or less than 1.0 nm, specifically, 0.5 nm. In addition, the curvature radius of the protrusion 47 is 1×10 -5 m to 1×10 - 3The structure of the protrusion 47 may be similar to the structure of the protrusion 43 , 45 , or 46 of Example 1, Example 2, or Example 3.

[0184] Except for the above points, the configuration and structure of the light-emitting element of Example 4 may be similar to the configuration and structure of the light-emitting element of Example 1, Example 2 or Example 3, so a detailed description thereof will be omitted.

[0185] In the manufacturing method of the light-emitting element of Example 4, first, similar to [Step-100] of Example 1, a laminated structure 20 is formed, in which a first compound semiconductor layer 21, an active layer (light-emitting layer) 23 and a second compound semiconductor layer 22 are laminated, the first compound semiconductor layer 21 includes a first surface 21a and a second surface 21b facing the first surface 21a, the active layer 23 faces the second surface 21b of the first compound semiconductor layer 21, and the second compound semiconductor layer 22 includes a first surface 22a facing the active layer 23 and a second surface 22b facing the first surface 22a, and then, similar to [Step-110] to [Step-120], a second electrode 32 and a second light reflecting layer 42 are formed on the second surface 22b of the second compound semiconductor layer 22.

[0186] Thereafter, in a step similar to [Step- 130 ] of Example 1, the protrusion 47 is formed on the first surface side of the first compound semiconductor layer 21 .

[0187] Then, the surface of the protrusion 47 is smoothed. Specifically, since the protrusion 47 includes, for example, a GaN substrate or a first compound semiconductor layer, the protrusion 47 can be smoothed based on a CMP method using colloidal silica as a polishing agent, and the protrusion 47 can be smoothed based on an immersion method using TMAH as an etching solution.

[0188] Alternatively, the surface of the protrusion 47 may be smoothed based on dry etching, specifically, based on the RIE method (reactive ion etching method). Here, the formation of the protrusion 47 is also performed based on the RIE method, and although it is based on the RIE equipment, it is only necessary to make the RIE conditions for smoothing on the protrusion 47 more isotropic than the RIE conditions at this time, that is, to reduce the bias voltage and increase the pressure when etching.

[0189] Thereafter, similarly to [Step-160] of Example 1, the first light reflecting layer 41 is formed on at least part of the protrusion 47, and the first electrode 31 electrically connected to the first compound semiconductor layer 21 is formed. In this way, a semiconductor device having Fig. 10A or Fig. 10B A light-emitting element of Example 4 of the structure illustrated in FIG.

[0190] Hereinafter, before describing Examples 5 to 12, a description will be given of various modifications of the light-emitting element of the present disclosure, a light-emitting element obtained by the method for manufacturing a light-emitting element according to the first aspect of the present disclosure, and a light-emitting element obtained by the method for manufacturing a light-emitting element according to the second aspect of the present disclosure (hereinafter, for convenience, these light-emitting elements are collectively referred to as "the light-emitting element of the present disclosure, etc.").

[0191] As described above, the current confinement region (the current injection region 61A and the current non-injection region 61B) is defined by the insulating layer 34 having the opening 34A. That is, the current injection region 61A is defined by the opening 34A. The second compound semiconductor layer 22 is provided with the current injection region 61A and the current non-injection region 61B surrounding the current injection region 61A, and the shortest distance D from the region center of gravity of the current injection region 61A to the boundary 61C between the current injection region 61A and the current non-injection region 61B is CI The following expression is satisfied. Here, for convenience, the light-emitting element having such a configuration is referred to as a "light-emitting element having a first configuration". Note that, as for the derivation of the following expression, see, for example, H. Kogelnik and T. Li, "Laser Beams and Resonators" (Applied Optics, Vol. 5, No. 10, October 1966). In addition, ω0 is also referred to as the beam waist radius.

[0192] D CI ≥ω0 / 2 (A)

[0193] in,

[0194] ω0 2 ≡(λ0 / π){L OR (R DBR -L OR )} 1 / 2 (B)

[0195] Here, the light emitting element having the first configuration includes a first light reflecting layer functioning as a concave mirror, and considering the symmetry of the second light reflecting layer with respect to the plane mirror, the resonator can be expanded to a Fabry-Perot resonator sandwiched between two concave mirrors having the same radius of curvature (see Fig. 22 ). At this time, the resonator length of the virtual Fabry-Perot resonator is the resonator length L OR twice as much. Fig.23 and Fig.24 The value of ω0 and the resonator length L are shown in the figure. OR and the radius of curvature R on the inner surface of the first light reflecting layer DBRNote that the fact that the value of ω0 is “positive” means that the laser beam schematically presents Fig.25A state, and the fact that the value of ω0 is "negative" means that the laser beam schematically presents Fig.25B The state of the laser beam can be Fig.25A The status shown in the figure or Fig.25B However, in a virtual Fabry-Perot resonator with two concave mirrors, when the radius of curvature R DBR Less than the resonator length L OR When Fig.25B In the state shown in the figure, the restriction becomes excessive and diffraction loss occurs. Therefore, it is preferred that the curvature radius R DBR Greater than the resonator length L OR ,This is Fig.25A . Note that when the active layer is arranged close to the flat light reflecting layer (specifically, the second light reflecting layer) of the two light reflecting layers, the light field is more focused in the active layer. That is, the light field confinement in the active layer is strengthened, and laser oscillation is promoted. As the position of the active layer, that is, the distance from the surface of the second light reflecting layer facing the second compound semiconductor layer to the active layer, an example may be λ0 / 2 to 10λ0, but is not limited thereto.

[0196] Incidentally, in the case where the region where the light reflected by the first light reflecting layer is focused is not included in the current injection region corresponding to the region where the active layer has gain due to current injection, stimulated emission of light from carriers is blocked, and as a result, laser oscillation is blocked. By satisfying the above expressions (A) and (B), it can be ensured that the region where the light reflected by the first light reflecting layer is focused is included in the current injection region, and laser oscillation can be reliably achieved.

[0197] Then, you can configure the following:

[0198] The light emitting element having the first configuration further comprises:

[0199] a mode loss action site which is provided on the second surface of the second compound semiconductor layer and constitutes a mode loss action region which acts on the increase or decrease of the oscillation mode loss, and

[0200] A second electrode is formed above the mode loss action site from the second surface of the second compound semiconductor layer, wherein

[0201] 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 laminated structure, and

[0202] The orthographic projection image of the mode loss effect region and the orthographic projection image of the current non-injection / external region overlap each other.

[0203] Then, in the light emitting element having the first configuration including such a preferred configuration, the radius r′ of the effective area of ​​the first light reflecting layer is DBR Can be configured to satisfy ω0≤r' DBR ≤20·ω0, preferably, ω0≤r' DBR ≤10·ω0. Alternatively, as r' DBR The value of r' DBR ≤1×10 -4 m, preferably, an example may be r' DBR ≤5×10 -5 m. In addition, in the light-emitting element having the first configuration including such a preferred configuration, it is possible to satisfy D CI ≥ω0. In addition, in the light emitting element having the first configuration including such a preferred configuration, the following configuration may be performed: 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 ≤5×10 -4 m.

[0204] After that, you can configure the following:

[0205] The light emitting element of the present disclosure also includes:

[0206] a mode loss action site which is provided on the second surface of the second compound semiconductor layer and constitutes a mode loss action region which acts on the increase or decrease of the oscillation mode loss, and

[0207] A second electrode is formed above the mode loss action site from the second surface of the second compound semiconductor layer, wherein

[0208] 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 laminated structure, and

[0209] The orthographic projection image of the mode loss action region and the orthographic projection image of the current non-injection / external region overlap each other. Here, for convenience, the light emitting element having such a configuration is referred to as a "light emitting element having a second configuration".

[0210] In the light-emitting element having the second 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 laminated structure, and 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 active layer, or may be formed from the second compound semiconductor layer over a portion of the first compound semiconductor layer. The orthogonal projection image of the mode loss action region and the orthogonal projection image of the current non-injection / outer region overlap with each other, but in a region sufficiently far from the current injection region, the orthogonal projection image of the mode loss action region and the orthogonal projection image of the current non-injection / outer region do not necessarily overlap with each other.

[0211] In the light emitting element having the second configuration, the current non-injection / external region may be configured to be located below the mode loss action region.

[0212] In a light-emitting element having a second configuration including the above-mentioned preferred configuration, when the area of ​​the orthographic projection image of the current injection region is S1 and the area of ​​the orthographic projection image of the current non-injection / internal region is S2, a configuration satisfying 0.01≤S1 / (S1+S2)≤0.7 can be achieved.

[0213] In the light-emitting element having the second configuration including the preferred configuration described above, the current non-injection / inner region and the current non-injection / outer region can be configured to be formed by ion implantation into the laminated structure. For convenience, the light-emitting element having this configuration is referred to as a "light-emitting element having the second configuration A". Then, in this case, the following configuration can be made: the ion species is at least one ion (that is, one ion, or more than or equal to two ions) from a group consisting of boron, protons, phosphorus, arsenic, carbon, nitrogen, fluorine, oxygen, germanium and silicon.

[0214] Alternatively, in the above-mentioned light-emitting element having a second configuration including a preferred configuration, the current non-injection / inner region and the current non-injection / outer region can be configured to be formed by plasma irradiation of the second surface of the second compound semiconductor layer, ashing of the second surface of the second compound semiconductor layer, or reactive ion etching (RIE) of the second surface of the second compound semiconductor layer. For convenience, the light-emitting element having such a configuration is referred to as a "light-emitting element having a second configuration B". In these multiple treatments, the current non-injection / inner region and the current non-injection / outer region are exposed to plasma particles, so that the conductivity of the second compound semiconductor layer deteriorates, and the current non-injection / inner region and the current non-injection / outer region are 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 exposing the second surface of the second compound semiconductor layer to plasma particles. Specific examples of plasma particles include argon, oxygen, nitrogen, etc.

[0215] Alternatively, in the above-mentioned light-emitting element having the second configuration including the preferred configuration, the second light-reflecting layer may include a region that reflects or scatters light from the first light-reflecting layer toward the outside of the resonator structure including the first light-reflecting layer and the second light-reflecting layer. For convenience, the light-emitting element having such a configuration is referred to as a "light-emitting element having the second configuration C". Specifically, a region of the second light-reflecting 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. In addition, the following configuration may also be adopted: 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, the light is scattered toward the outside of the resonator structure including the first light-reflecting layer and the second light-reflecting layer.

[0216] In the above-mentioned light-emitting element with the second configuration A, the light-emitting element with the second configuration B, or the light-emitting element with the second configuration C, the following configuration may be made: when the optical distance from the active layer in the current injection region to the second surface of the second compound semiconductor layer is L2 and the optical distance from the active layer in the mode loss action region to the top surface of the mode loss action site is L0, L0>L2 is satisfied. In addition, in the above-mentioned light-emitting element with the second configuration A, the light-emitting element with the second configuration B, or the light-emitting element with the second configuration C including such a configuration, the following configuration may be made: the generated light with a higher-order mode is dissipated toward the outside of the resonator structure including the first light reflection layer and the second light reflection layer through the mode loss action region, and thus the oscillation mode loss increases. That is, due to the existence of a mode loss action region that affects the increase or decrease of the oscillation mode loss, in the positive projection image of the mode loss action region, the light field intensities of the generated fundamental mode and higher-order modes decrease with increasing distance from the Z-axis, but the mode loss in the higher-order modes is greater than the decrease in the light field intensity of the fundamental mode, and compared with the case where there is no current injected into the internal region, the fundamental mode can be further stabilized and the mode loss can be suppressed, so that the threshold current can be reduced.

[0217] In addition, in the above-mentioned light emitting element having the second configuration A, the light emitting element having the second configuration B or the light emitting element having the second configuration C, the mode loss action site may include a dielectric material, a metal material or an alloy material. As a dielectric material, an example may be SiO X 、SiN X 、AlN X 、AlO X 、TaO X 、ZrO X , and as a metal material or an alloy material, examples may be titanium, gold, platinum or an alloy thereof; however, the material is not limited thereto. The mode loss action site including these materials may be made to absorb light, causing the mode loss to increase. Alternatively, even if the light is not directly absorbed, the mode loss may be controlled by perturbing the phase. In this case, the following configuration may be made: the mode loss action site includes a dielectric material, and the optical thickness t0 of the mode loss action site has a value that deviates from an integer multiple of 1 / 4 of the oscillation wavelength λ0. That is, the standing wave may be destroyed by perturbing the phase of the light that circulates in the resonator and forms a standing wave at the mode loss action site, and the corresponding mode loss is given. Alternatively, the following configuration may be made: the mode loss action site includes a dielectric material, and the mode loss action site (refractive index n m-loss) The optical thickness t0 is an integer multiple of 1 / 4 of the oscillation wavelength λ0. That is to say, the following configuration can be made: the optical thickness t0 of the mode loss acting part is the thickness when the phase of the light generated in the light-emitting element is not disturbed and the standing wave is not destroyed. However, it does not have to be exactly an integer multiple of 1 / 4, as long as it satisfies

[0218] (λ0 / 4n m-loss )×m-(λ0 / 8n m-loss )≤t0≤(λ0 / 4n m-loss )×2m+(λ0 / 8n m-loss ).

[0219] Alternatively, by forming the mode loss acting part to include a dielectric material, a metal material or an alloy material, the mode loss acting part can disturb the phase or absorb the light passing through the mode loss acting part. Then, by adopting these configurations, the oscillation mode loss can be controlled with higher degrees of freedom, and the degrees of freedom in designing the light-emitting element can be further increased.

[0220] Alternatively, in the light-emitting element having the second configuration including the above preferred configuration, the following configuration can be made:

[0221] A protrusion is formed on the second surface side of the second compound semiconductor layer, and

[0222] A mode loss acting part is formed on the region of the second surface of the second compound semiconductor layer surrounding the protrusion. For convenience, the light-emitting element having such a configuration is referred to as "the light-emitting element having the second configuration D". The protrusion occupies the current injection region and the current non-injection / internal region. Then, in this case, the following configuration can be made: when the optical distance from the active layer in the current injection region to the second surface of the second compound semiconductor layer is L2 and the optical distance from the active layer in the mode loss acting region to the top surface of the mode loss acting part is L0, L0 < L2 is satisfied. In addition, in these cases, the following configuration can be made: the light having a higher-order mode generated is restricted by the mode loss acting region in the current injection region and the current non-injection / internal region, so that the oscillation mode loss is reduced. That is to say, due to the presence of the mode loss acting region that acts on the increase or decrease of the oscillation mode loss, in the positive projection images of the current injection region and the current non-injection / internal region, the light field intensities of the generated fundamental mode and higher-order mode increase. In addition, in these cases, the mode loss acting part can include a dielectric material, a metal material or an alloy material. Here, as the dielectric material, metal material or alloy material, various materials mentioned above can be mentioned.

[0223] In addition, in the above-mentioned light-emitting element of the present disclosure including preferred embodiments and configurations, etc. (including the light-emitting element having the first configuration to the light-emitting element having the second configuration), the following configuration may be performed: in the laminated structure including the second electrode, at least two light-absorbing material layers are formed in parallel with the virtual plane occupied by the active layer. Here, for convenience, the light-emitting element having such a configuration is referred to as a "light-emitting element having a third configuration". In the light-emitting element having the third configuration, it is preferred to form at least four light-absorbing material layers.

[0224] In the above-mentioned light emitting element having the third configuration including the preferred configuration, when the oscillation wavelength (the wavelength of light mainly emitted from the light emitting element and being the desired oscillation wavelength) is λ0, the total equivalent refractive index of the two light absorbing material layers and a portion of the laminated structure located between the light absorbing material layers and the light absorbing material layers is n eq , and the distance between the light absorbing material layers is L Abs When

[0225] 0.9×{(m·λ0) / (2·n eq )}≤L Abs ≤1.1×{(m·λ0) / (2·n eq )}.

[0226] Here, m is 1 or any integer greater than or equal to 2, including 1. When the thickness of each of the layers constituting the two light absorbing material layers and a portion between the light absorbing material layers and the light absorbing material layer of the laminated structure is t i And the refractive index is n i When the equivalent refractive index n eq is represented as

[0227] n eq =Σ(t i ×n i ) / Σ(t i ).

[0228] However, i=1, 2, 3, ..., I, "I" is the total number of layers constituting the two light absorbing material layers and a portion between the light absorbing material layer and the light absorbing material layer of the laminated structure, and "∑" means taking the sum from i=1 to i=I. It is only necessary to observe the cross-section of the light emitting element by electron microscope observation, etc. and calculate the equivalent refractive index n based on the known refractive index of each constituent material and the thickness of each constituent material obtained by observation. eq When m is 1, in all the multiple light absorbing material layers, the distance between adjacent light absorbing material layers satisfies:

[0229] 0.9×{λ0 / (2·n eq)}≤L Abs ≤1.1×{λ0 / (2·n eq )}. In addition, when m is any integer greater than or equal to 2 and including 1, for example, if m=1, 2, then in some light absorbing material layers, the distance between adjacent light absorbing material layers satisfies 0.9×{λ0 / (2·n eq )}≤L Abs ≤1.1×{λ0 / (2·n eq )}, and in the remaining light absorbing material layers, the distance between adjacent light absorbing material layers satisfies 0.9×{(2·λ0) / (2·n eq )}≤L Abs ≤1.1×{(2·λ0) / (2·n eq )}.

[0230] In general, in some light absorbing material layers, the distance between adjacent light absorbing material layers satisfies 0.9×{λ0 / (2·n eq )}≤L Abs ≤1.1×{λ0 / (2·n eq )}, and in the remaining various light absorbing material layers, the distance between adjacent light absorbing material layers satisfies 0.9×{(m'·λ0) / (2·n eq )}≤L Abs ≤1.1×{(m'·λ0) / (2·n eq )}.

[0231] Here, m' is an arbitrary integer greater than or equal to 2. In addition, the distance between adjacent light absorbing material layers is the distance between the centers of gravity of adjacent light absorbing material layers. That is, in fact, it is the distance between the centers of the respective light absorbing material layers when cut in a virtual plane along the thickness direction of the active layer.

[0232] Furthermore, in the above-mentioned light emitting element having the third configuration including various preferred configurations, the thickness of the light absorbing material layer is preferably less than or equal to λ0 / (4·n eq ). As the lower limit value of the thickness of the light absorbing material layer, an example may be 1 nm.

[0233] Furthermore, in the above-described light emitting element having the third configuration including various preferred configurations, a configuration may be made in which the light absorbing material layer is located at a minimum amplitude portion generated in a standing wave of light formed inside the laminated structure.

[0234] Furthermore, in the above-described light emitting element having the third configuration including various preferred configurations, a configuration may be made in which the active layer is located at a maximum amplitude portion generated in a standing wave of light formed inside the laminated structure.

[0235] Furthermore, in the above-mentioned light-emitting element having the third configuration including various preferred configurations, the following configuration may be made: the light absorption coefficient of the light-absorbing material layer is two or more times the light absorption coefficient of the compound semiconductor constituting the laminated structure. Here, the light absorption coefficient of the light-absorbing material layer constituting the laminated structure and the light absorption coefficient of the compound semiconductor are obtained by observing the constituent materials and the like by observing the cross section of the light-emitting element with an electron microscope and deriving the coefficients using known estimated results observed for the corresponding constituent materials.

[0236] Furthermore, in the above-mentioned light-emitting element having the third configuration including various preferred configurations, the following configuration may be performed: the light-absorbing material layer includes at least one material, and the at least one material is selected from the group consisting of a compound semiconductor material having a band gap narrower than that of the compound semiconductor constituting the laminated structure, a compound semiconductor material doped with impurities, a transparent conductive material, and a light-reflecting layer-constituting material having a light-absorbing property. Here, as the compound semiconductor material having a band gap narrower than that of the compound semiconductor constituting the laminated structure, for example, in the case where the compound semiconductor constituting the laminated structure is GaN, InGaN may be mentioned; as the compound semiconductor material doped with impurities, Si-doped n-GaN and B-doped n-GaN may be mentioned; as the transparent conductive material, a transparent conductive material constituting an electrode may be mentioned; and as the light-reflecting layer-constituting material having a light-absorbing property, a material constituting the light-reflecting layer (for example, SiO X 、SiN X 、TaO X All light absorbing material layers may include one of these materials. Alternatively, each light absorbing material layer may include various materials selected from these materials, but from the perspective of simplifying the formation of the light absorbing material layer, it is preferred that one light absorbing material layer includes one material. The light absorbing material layer may be formed in the first compound semiconductor layer, may be formed in the second compound semiconductor layer, or may be formed in the second light reflecting layer, or any combination of these may be used. Alternatively, the light absorbing material layer may also be used as an electrode including a transparent conductive material.

[0237] Hereinafter, Examples 5 to 12 will be described.

[0238] [Example 5]

[0239] Example 5 is a variation of Examples 1 to 4, and relates to a light-emitting element having the first configuration. As described above, the current confinement region (the current injection region 61A and the current non-injection region 61B) is defined by the insulating layer 34 having the opening 34A. That is, the current injection region 61A is defined by the opening 34A. That is, in the light-emitting element of Example 5, the second compound semiconductor layer 22 is provided with the current injection region 61A and the current non-injection region 61B surrounding the current injection region 61A, and the shortest distance D from the region centroid of the current injection region 61A to the boundary 61C between the current injection region 61A and the current non-injection region 61B is CI The above expressions (A) and (B) are satisfied.

[0240] In the light emitting element of Example 5, the radius r′ of the effective region 41 b of the first light reflecting layer 41 is DBR satisfy:

[0241] ω0≤r' DBR ≤20·ω0.

[0242] In addition, satisfying D CI ≥ω0. In addition, R DBR ≤1×10 -3 m. Specifically, the following examples can be given:

[0243] D CI =4μm,

[0244] ω0=1.5μm,

[0245] L OR =30μm,

[0246] R DBR =60μm,

[0247] λ0=525nm.

[0248] In addition, 8 μm can be an example of the diameter of the opening 34A. As the GaN substrate, a substrate whose main surface is a surface in which the c-plane is inclined by about 75 degrees in the m-axis direction is used. That is, the GaN substrate includes the {20-21} plane as a semipolar plane as the main surface. Note that such a GaN substrate can also be used in other examples.

[0249] The deviation of the central axis (Z axis) of the protrusion from the current injection region 61A in the XY plane direction causes the characteristics of the light-emitting element to deteriorate. Usually, photolithography technology is used to perform both patterning of the protrusion and patterning of the opening 34A, but in this case, the positional relationship between the two often deviates in the XY plane according to the performance of the exposure machine. Specifically, the opening 34A (current injection region 61A) is positioned by aligning from the side of the second compound semiconductor layer 22. On the other hand, the protrusion is positioned by aligning from the side of the compound semiconductor substrate 11. Therefore, in the light-emitting element of Example 5, the opening 34A (current injection region 61) is formed to be larger than the area in which the light is focused by the protrusion, thereby achieving a structure in which the oscillation characteristics are not affected even if there is a deviation between the central axis (Z axis) and the current injection region 61A in the XY plane direction.

[0250] That is, in the case where the region in which the light reflected by the first light reflecting layer is focused is not included in the current injection region, wherein the current injection region corresponds to the region in which the active layer has gain due to current injection, stimulated emission of light from carriers is blocked, and as a result, laser oscillation is blocked. However, by satisfying the above expressions (A) and (B), it can be ensured that the region in which the light reflected by the first light reflecting layer is focused is included in the current injection region, and laser oscillation can be reliably achieved.

[0251] [Example 6]

[0252] Example 6 is a variation of Examples 1 to 5, and relates to a light emitting element having a second configuration, specifically, a light emitting element having a second configuration A. Fig.11 A schematic partial end view of a light emitting element of Example 6 is illustrated.

[0253] Incidentally, in order to control the flow path (current injection region) of the current flow between the first electrode and the second electrode, the current non-injection region is formed to surround the current injection region. In a GaAs-based surface-emitting laser element (including a surface-emitting laser element of a GaAs-based compound semiconductor), the current non-injection region surrounding the current injection region can be formed by oxidizing the active layer from the outside along the XY plane. The oxidized active layer region (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. As a result, a "lens effect" is generated, and the effect of limiting the laser beam to the central part of the surface-emitting laser element is caused. Generally, since light tends to diffuse due to the diffraction effect, the laser beam reciprocating in the resonator gradually dissipates to the outside of the resonator (diffraction loss), thereby causing adverse effects such as an increase in the threshold current. However, since the lens effect compensates for the diffraction loss, the increase in the threshold current, etc. can be suppressed.

[0254] However, in a light-emitting element including a GaN-based compound semiconductor, due to the characteristics of the material, it is difficult to oxidize the active layer from the outside (from the lateral direction) along the XY plane. Therefore, as described in Examples 1 to 5, an insulating layer 34 containing SiO2 including an opening 34A is formed on the second compound semiconductor layer 22, a second electrode 32 including a transparent conductive material is exposed from the bottom of the opening 34A. The second compound semiconductor layer 22 is formed above the insulating layer 34, and a second light reflecting layer 42 of a laminated structure including an insulating material is formed on the second electrode 32. By forming the insulating layer 34 in this way, a current non-injection region 61B is formed. Then, a portion of the second compound semiconductor layer 22 located in the opening 34A provided in the insulating layer 34 becomes the current injection region 61A.

[0255] In the case where the insulating layer 34 is formed on the second compound semiconductor layer 22, the resonator length in the region (current non-injection region 61B) where the insulating layer 34 is formed is longer than the resonator length in the region (current injection region 61A) where the insulating layer 34 is not formed by the optical thickness of the insulating layer 34. Therefore, an effect occurs in which the laser beam reciprocating in the resonator formed by the two light reflection layers 41 and 42 of the surface-emitting laser element (light-emitting element) diverges and diverges to the outside of the resonator. For convenience, such an effect is called a "reverse lens effect". Then, as a result, oscillation mode loss occurs in the laser beam, and there is a possibility that the threshold current increases or the slope efficiency decreases. Here, "oscillation mode loss" is a physical quantity that increases or decreases the light field intensity of the fundamental mode and the higher-order mode in the oscillated laser beam, and different oscillation mode losses are defined for the corresponding modes. Note that "light field intensity" is the light field intensity as a function of the distance L from the Z axis in the XY plane, and generally, in the fundamental mode, the light field intensity decreases monotonically with increasing distance L, but in higher-order modes, the light field intensity increases, decreases, and then decreases once or more with increasing distance L (see Fig.13 ). Note that in Fig.13 In , the solid line shows the light field intensity distribution under the fundamental mode, and the dashed line shows the light field intensity distribution under the higher-order mode. Fig.13 , for convenience, the first light reflecting layer 41 is shown in a flat state, but it is actually formed on a protruding portion.

[0256] A light emitting element of Example 6 or each of light emitting elements of Examples 7 to 9 described later includes:

[0257] (A) A laminated structure 20 including a GaN-based compound semiconductor, wherein the following are laminated:

[0258] A first compound semiconductor layer 21 including a first surface 21 a and a second surface 21 b facing the first surface 21 a;

[0259] The active layer (light emitting layer) 23 facing the second surface 21b of the first compound semiconductor layer 21 and

[0260] The second compound semiconductor layer 22 includes a first surface 22 a facing the active layer 23 and a second surface 22 b facing the first surface 22 a.

[0261] (B) a mode loss action site (mode loss action layer) 54, which is provided on the second surface 22b of the second compound semiconductor layer 22 and constitutes a mode loss action region 55 that acts on the increase or decrease of the oscillation mode loss, and

[0262] (C) a second electrode formed above the mode loss action site 54 from the second surface 22b of the second compound semiconductor layer 22;

[0263] (D) a second light reflecting layer 42 formed on the second electrode 32;

[0264] (E) a first light reflecting layer 41;

[0265] (F) a first electrode 31; and

[0266] (G) The protrusions 45 , 46 , 47 or the protrusion 43 and the smooth layer 44 .

[0267] Then, in the laminated structure 20, a current injection region 51, a current non-injection / internal region 52 surrounding the current injection region 51, and a current non-injection / external region 53 surrounding the current non-injection / internal region 52 are formed, and the orthographic projection image of the mode loss action region 55 overlaps with the orthographic projection image of the current non-injection / external region 53. That is, the current non-injection / external region 53 is located below the mode loss action region 55. Note that in an area sufficiently far from the current injection region 51 into which the current is injected, the orthographic projection image of the mode loss action region 55 and the orthographic projection image of the current non-injection / external region 53 do not necessarily overlap with each other. Here, in the laminated structure 20, current non-injection regions 52 and 53 into which no current is injected are formed, and in the illustrated example, it is formed above a portion of the first compound semiconductor layer 21 from the second compound semiconductor layer 22 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 on the second compound semiconductor layer 22 and the active layer 23 .

[0268] The mode loss action site (mode loss action layer) 54 includes a dielectric material such as SiO2, and is formed between the second electrode 32 and the second compound semiconductor layer 22 in the light-emitting elements of Example 6 or Examples 7 to 9 described later. The optical thickness of the mode loss action site 54 can be set to a value that deviates from an integer multiple of 1 / 4 of the oscillation wavelength λ0. Alternatively, the optical thickness t0 of the mode loss action site 54 can be set to an integer multiple of 1 / 4 of the oscillation wavelength λ0. That is, the optical thickness t0 of the mode loss action site 54 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 have to be exactly an integer multiple of 1 / 4, and only needs to satisfy: (λ0 / 4n m-loss )×m-(λ0 / 8n m-loss )≤t0≤(λ0 / 4n m-loss )×2m+(λ0 / 8nm-loss ).

[0269] Specifically, when the value of 1 / 4 of the wavelength of light generated by the light emitting element is "100", the optical thickness t0 of the mode loss action site 54 is preferably about 25 to 250. Then, by adopting these configurations, the phase difference between the laser beam passing through the mode loss action site 54 and the laser beam passing through the current injection region 51 can be changed (the phase difference can be controlled), and the oscillation mode loss can be controlled with a higher degree of freedom, and the degree of freedom in designing the light emitting element can be further increased.

[0270] In Example 6, the shape of the boundary between the current injection region 51 and the current non-injection / internal region 52 is a circle (diameter: 8 μm), and the shape of the boundary between the current non-injection / internal region 52 and the current non-injection / external region 53 is a circle (diameter: 12 μm). That is, when the area of ​​the orthographic projection image of the current injection region 51 is S1 and the area of ​​the orthographic projection image of the current non-injection / internal region 52 is S2, it satisfies: 0.01≤S1 / (S1+S2)≤0.7. Specifically, S1 / (S1+S2)=8 2 / 12 2 =0.44.

[0271] In the light-emitting elements of Examples 6 or Examples 7 to 8 described subsequently, when the optical distance from the active layer 23 in the current injection region 51 to the second surface of the second compound semiconductor layer 22 is L2, and the optical distance from the active 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 L0, L0>L2 is satisfied. Specifically, L0 / L2=1.5 is set. Then, the generated laser beam having a higher-order mode diverges toward the outside of the resonator structure including the first light reflection layer 41 and the second light reflection layer 42 due to the mode loss action region 55, so that the oscillation mode loss increases. That is, due to the presence of the mode loss action region 55 that acts on the increase or decrease of the oscillation mode loss, the light field intensity of the generated fundamental mode and higher-order mode decreases as the distance from the Z axis in the positive projection image of the mode loss action region 55 increases (see Fig.13 ), but the decrease in the light field intensity in the higher-order mode is greater than the decrease in the light field intensity in the fundamental mode, and the fundamental mode can be further stabilized, the threshold current can be reduced, and the relative light field intensity in the fundamental mode can be increased. In addition, the hem portion of the light field intensity in the higher-order mode is located farther from the current injection region than in a conventional light-emitting element (see Fig.13 (A)) makes it possible to reduce the influence of the anti-lens effect. Note that, first, in the case where the mode loss action portion 54 containing SiO2 is not provided, oscillation mode mixing occurs.

[0272] The first compound semiconductor layer 21 includes an n-GaN layer; the active layer 23 includes an In 0.04 Ga 0.96 N layer (barrier layer) and In 0.16 Ga 0.84 N layer (well layer) laminated five-layer multi-quantum well result; and the second compound semiconductor layer 22 includes a p-GaN layer. In addition, the first electrode 31 includes Ti / Pt / Au, and the second electrode 32 includes a transparent conductive material, specifically, ITO. A circular opening 54A is formed at the mode loss action site 54, and the second compound semiconductor layer 22 is exposed at the bottom of the opening 54A. On the edge of the first electrode 31, a pad electrode (not shown) for electrical connection to an external electrode or circuit is formed or connected, and the pad electrode includes, for example, Ti / Pt / Au or V / Pt / Au. On the edge of the second electrode 32, a pad electrode 33 for electrical connection to an external electrode or circuit is formed or connected, and the pad electrode 33 includes, for example, Ti / Pd / Au or Ti / Ni / Au. The first light reflecting layer 41 and the second light reflecting layer 42 include a laminated structure of a SiN layer and a SiO2 layer (the total number of laminated layers of the dielectric film: 20 layers).

[0273] In the light emitting element of Example 6, the current non-injection / inner region 52 and the current non-injection / outer region 53 are formed by ion implantation into the laminated structural body 20. For example, boron is selected as the ion species, but the ion species is not limited to boron ions.

[0274] Hereinafter, an overview of a method for manufacturing a light emitting element of Example 6 will be described.

[0275] [Step- 600 ] When manufacturing the light emitting element of Example 6, first, a step similar to [Step- 100 ] of Example 1 is performed.

[0276] [STEP-610]

[0277] Next, based on the ion implantation method using boron ions, the current non-implantation / inner region 52 and the current non-implantation / outer region 53 are formed in the laminated structural body 20 .

[0278] [STEP-620]

[0279] Thereafter, in a step similar to [Step-110] of Example 1, a mode loss action site (mode loss action layer) 54 including the opening 54A and containing SiO2 is formed on the second surface 22b of the second compound semiconductor layer 22 based on a well-known method.

[0280] [STEP-630]

[0281] Thereafter, by performing steps similar to [Step-120] to [Step-160] of Example 1, the light emitting element of Example 6 can be obtained.

[0282] In the light-emitting element of Example 6, 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, and the orthographic projection image of the mode loss action region and the orthographic projection image of the current non-injection / outer region overlap each other. That is, the current injection region and the mode loss action region are separated (disconnected) by the current non-injection / inner region. Therefore, as Fig.13 As illustrated in the concept in (B), the increase / decrease of the oscillation mode loss (specifically, an increase in Example 6) can be made into a desired state. Alternatively, the increase / decrease of the oscillation mode loss can be made into a desired state by appropriately determining the positional relationship between the current injection region and the mode loss action region, the thickness of the mode loss action portion constituting the mode loss action region, etc. Then, as a result, problems in conventional light-emitting elements, such as an increase in threshold current and a decrease in slope efficiency, can be solved. For example, the threshold current can be reduced by reducing the oscillation mode loss of the fundamental mode. In addition, since the region in which the oscillation mode loss is given and the region in which the current is injected and contributes to the light emission can be independently controlled, that is, the control of the oscillation mode loss and the control of the light-emitting state of the light-emitting element can be independently performed, the control freedom and design freedom 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-mentioned predetermined arrangement relationship, the amplitude relationship of the oscillation mode loss given to the fundamental mode and the higher-order mode by the mode loss action region can be controlled, and by making the oscillation mode loss given to the higher-order mode relatively large relative to the oscillation mode loss given to the fundamental mode, the fundamental mode can be further stabilized. In addition, since the light-emitting element of Example 6 also includes a protrusion, the occurrence of diffraction loss can be more reliably suppressed.

[0283] [Example 7]

[0284] Example 7 is a variation of Example 6, and relates to a light emitting element having a second configuration B. Fig.14As illustrated in the schematic partial end view in , in the light-emitting element of Example 7, the current non-injection / inner region 52 and the current non-injection / external region 53 are formed by plasma irradiating the second surface of the second compound semiconductor layer 22, ashing the second surface of the second compound semiconductor layer 22, or reactive ion etching (RIE) the second surface of the second compound semiconductor layer 22. Then, since the current non-injection / inner region 52 and the current non-injection / external region 53 are 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 / external region 53 are in a high resistance state. That is, the current non-injection / inner region 52 and the current non-injection / external region 53 are formed by exposing the second surface 22b of the second compound semiconductor layer 22 to plasma particles. Note that in Fig.14 , Fig.15 , Fig.16 and Fig.17 In the figure, the first electrode 31, the protrusions 43, 45, 46 and 47, and the smoothing layer 44 are not shown.

[0285] In addition, in Example 7, the shape of the boundary between the current injection region 51 and the current non-injection / internal region 52 is a circle (diameter: 10 μm), and the shape of the boundary between the current non-injection / internal region 52 and the current non-injection / external region 53 is a circle (diameter: 15 μm). That is, when the area of ​​the orthographic projection image of the current injection region 51 is S1 and the area of ​​the orthographic projection image of the current non-injection / internal region 52 is S2, 0.01≤S1 / (S1+S2)≤0.7 is satisfied. Specifically, S1 / (S1+S2)=10 2 / 15 2 =0.44.

[0286] In Example 7, instead of [Step-610] of Example 6, it is only necessary to form a current non-injection / internal region 52 and a current non-injection / external region 53 in the laminated structure 20 based on plasma irradiation of the second surface of the second compound semiconductor layer 22, ashing treatment of the second surface of the second compound semiconductor layer 22, or reactive ion etching treatment of the second surface of the second compound semiconductor layer 22.

[0287] Except for the above points, the configuration and structure of the light emitting element of Example 7 may be similar to the configuration and structure of the light emitting element of Example 6, and thus a detailed description thereof will be omitted.

[0288] Even in the light-emitting elements of Example 7 or Example 8 described later, by setting the current injection region, the current non-injection region and the mode loss action region into the above-mentioned predetermined arrangement relationship, the relationship between the magnitude of the oscillation mode loss given to the fundamental mode and the higher-order mode by the mode loss action region can be controlled, and by making the oscillation mode loss given to the higher-order mode relatively large relative to the oscillation mode loss given to the fundamental mode, the fundamental mode can be further stabilized.

[0289] [Example 8]

[0290] Example 8 is a variation of Examples 6 to 7, and relates to a light emitting element having a second configuration C. Fig.15 As illustrated in the schematic partial end view of , in the light emitting element of Example 8, the second light reflecting layer 42 includes a portion that reflects or scatters light from the first light reflecting layer 41 toward the outside (that is, toward the mode loss action region 55) of the resonator structure including the first light reflecting layer 41 and the second light reflecting layer 42. Specifically, a portion of the second light reflecting layer 42 located above the side wall (side wall of the opening 54B) of the mode loss action site (mode loss action layer) 54 includes a forward tapered inclined portion 42A, or alternatively, includes a region that convexly bends toward the first light reflecting layer 41.

[0291] In Example 8, the shape of the boundary between the current injection region 51 and the current non-injection / inner region 52 is circular (diameter: 8 μm), and the shape of the boundary between the current non-injection / inner region 52 and the current non-injection / outer region 53 is circular (diameter: 10 μm to 20 μm).

[0292] In Example 8, when a mode loss action site (mode loss action layer) 54 including an opening 54B and containing SiO2 is formed in a step similar to [Step-620] of Example 6, it is only necessary to form an opening 54B including a forward tapered sidewall. 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 set on a portion of the resist layer where the opening 54B is to be formed based on a photolithography technique. Based on a known method, the sidewall of the opening is made into a shape having a forward tapered shape. Then, by performing back etching, an opening 54B including a forward tapered sidewall can be formed at the mode loss action site (mode loss action layer) 54. In addition, 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 forward tapered inclined portion 42A can be given to the second light reflection layer 42.

[0293] Except for the above points, the configuration and structure of the light emitting element of Example 8 may be similar to the configuration and structure of the light emitting elements of Examples 6 to 7, and thus a detailed description thereof will be omitted.

[0294] [Example 9]

[0295] Example 9 is a modification of Examples 6 to 8 and relates to a light-emitting element having a second configuration D. Fig.16 FIG. shows a schematic partial end view of the light-emitting element of Example 9, and as Fig.17 shown in the schematic partial end view in which a main part is cut, a protrusion 22A is formed on the second surface 22b side of the second compound semiconductor layer 22. Then, as Fig.16 and Fig.17 shown, a mode loss acting portion (mode loss acting layer) 54 is formed on a region 22B of the second surface 22b of the second compound semiconductor layer 22 that surrounds the protrusion 22A. The protrusion 22A occupies the current injection region 51 and the current non-injection / internal region 52. The mode loss acting portion (mode loss acting layer) 54 includes a dielectric material, for example, SiO2, similar to Example 6. The region 22B is provided with a current non-injection / external region 53. When the optical distance from the active layer 23 in the current injection region 51 to the second surface of the second compound semiconductor layer 22 is L2 and the optical distance from the active layer 23 in the mode loss acting region 55 to the top surface (the surface facing the second electrode 32) of the mode loss acting portion 54 is L0, L0 < L2 is satisfied. Specifically, L2 / L0 = 1.5 is set. As a result, a lens effect is generated in the light-emitting element.

[0296] In the light-emitting element of Example 9, the generated laser beam having a higher-order mode is restricted to the current injection region 51 and the current non-injection / internal region 52 due to the mode loss acting region 55, and thus the oscillation mode loss is reduced. That is, due to the presence of the mode loss acting region 55 that acts to increase or decrease the oscillation mode loss, the light field intensity of the generated fundamental mode and higher-order mode increases in the orthographic projection image of the current injection region 51 and the current non-injection / internal region 52.

[0297] In Example 9, the shape of the boundary between the current injection region 51 and the current non-injection / internal region 52 is circular (diameter: 8 μm), and the boundary between the current non-injection / internal region 52 and the current non-injection / external region 53 is circular (diameter: 30 μm).

[0298] In Example 9, it is only necessary to remove a part of the second compound semiconductor layer 22 from the second surface 22b side between [Step - 610] and [Step - 620] of Example 6 to form the protrusion 22A.

[0299] Except for the above points, the configuration and structure of the light emitting element of Example 9 may be similar to those of the light emitting element of Example 6, and thus a detailed description thereof will be omitted. In the light emitting element of Example 9, not only can the oscillation mode loss imparted by the mode loss action region to various modes be suppressed, and the lateral mode be made to oscillate in a plurality of modes, but also the threshold of laser oscillation can be reduced. In addition, as Fig.13 As illustrated in the conceptual diagram in (C), due to the existence of a mode loss action region that acts on the increase or decrease (specifically, reduction in Example 9) of the oscillation mode loss, the light field intensity of the fundamental mode and higher-order modes generated in the positive projection image of the current injection region and the current non-injection / internal region can be increased.

[0300] [Example 10]

[0301] Example 10 is a variation of Examples 1 to 9, and relates to a light emitting element having a third configuration.

[0302] By the way, when the equivalent refractive index of the entire boost structure is n eq When the wavelength λ of the laser beam emitted from the surface emitting laser element (light emitting element) is 0, the resonator length L in the laminated structure including two DBR layers and the laminated structure formed therebetween is OR It is expressed as L = (m·λ0) / (2·n eq ).

[0303] Here, m is a positive integer. Then, in the surface emitting laser element (light emitting element), the wavelength that can be oscillated is determined by the resonator length L OR Each oscillation mode that can oscillate is called a longitudinal mode. Then, among the longitudinal modes, the longitudinal mode that matches the gain spectrum determined by the active layer can cause laser oscillation. When the effective refractive index is n eff When the longitudinal mode spacing Δλ is expressed as λ0 2 / (2n eff ·L).

[0304] That is, the resonator length L OR The longer the resonator length L, the narrower the longitudinal mode spacing Δλ. OR When the oscillation wavelength is λ0, the equivalent refractive index n eq With the effective refractive index n eff Has the following relationship.

[0305] n eff =n eq -λ0·(dn eq / dλ0).

[0306] Here, in the case where the laminated structure includes a GaAs-based compound semiconductor layer, the resonator length L OR Often as short as 1 μm or less, and one type (one wavelength) of longitudinal mode laser beam is emitted from a surface emitting laser element (see Fig.26A ). Therefore, the oscillation wavelength of the longitudinal mode laser beam emitted from the surface emitting laser element can be accurately controlled. On the other hand, in the case where the laminated structure includes a GaN-based compound semiconductor layer, the resonator length L OR It is often several times longer than the wavelength of the laser beam emitted from the surface emitting laser element. Therefore, it is possible to emit various types of longitudinal mode laser beams from the surface emitting laser element (see Fig.26B ).

[0307] like Fig.18 As illustrated in the schematic partial end view in , in the light emitting element of Example 10 or the light emitting elements of Examples 11 to 12 described later, in the laminated structure 20 including the second electrode 32, at least two light absorbing material layers 71, preferably at least four light absorbing material layers 71 (specifically, in Example 10, twenty light absorbing material layers 71 are formed) are formed in parallel with the virtual plane occupied by the active layer 23. Note that, in order to simplify the drawings, only two light absorbing material layers 71 are illustrated in the figure.

[0308] In Example 10, the oscillation wavelength (desired oscillation wavelength emitted from the light emitting element) λ0 is 450 nm. The twenty light absorbing material layers 71 include a compound semiconductor material having a narrower band gap than the compound semiconductor constituting the laminated structure 20, specifically, n-In 0.2 GA 0.8 N, and is formed inside the first compound semiconductor layer 21. The thickness of the light absorbing material layer 71 is less than or equal to λ0 / (4·n eq ), specifically, 3 nm. In addition, the light absorption coefficient of the light absorption material layer 71 exceeds twice the light absorption coefficient of the first compound semiconductor layer 21 containing the n-GaN layer, specifically, 1×10 3 times.

[0309] In addition, the light absorbing material layer 71 is located at the minimum amplitude portion generated in the standing wave of light formed inside the laminated structure, and the active 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 active layer 23 and the center in the thickness direction of the light absorbing material layer 71 adjacent to the active layer 23 is 46.5 nm. In addition, when the total equivalent refractive index of the two light absorbing material layers 71 and a portion of the laminated structure located between the light absorbing material layers 71 and the light absorbing material layers 71 (specifically, in Example 10, the first compound semiconductor layer 21) is neq And the distance between the light absorbing material layers 71 is L Abs When 0.9×{(m·λ0) / (2·n eq )}≤L Abs ≤1.1×{(m·λ0) / (2·n eq )}. Here, m is 1 or any integer greater than or equal to 2, including 1. However, in Example 10, m=1 is set. Therefore, in all the plurality of light absorbing material layers 71 (twenty light absorbing material layers 71), the distance between adjacent light absorbing material layers 71 satisfies 0.9×{λ0 / (2·n eq )}≤L Abs ≤1.1×{λ0 / (2·n eq )}. Equivalent refractive index n eq The value of is specifically 2.42, and when m=1, specifically, L Abs =1×450 / (2×2.42)=93.0nm.

[0310] Note that, among the twenty light absorbing material layers 71 , m may be set to any integer greater than or equal to 2 in some of the light absorbing material layers 71 .

[0311] When manufacturing the light-emitting element of Example 10, the laminated structure 20 is formed in a step similar to [Step-100] of Example 1, and at this time, twenty light-absorbing material layers 71 are also formed inside the first compound semiconductor layer 21. Except for this point, the light-emitting element of Example 10 can be manufactured based on a method similar to the method of the light-emitting element of Example 1.

[0312] In the case where multiple longitudinal modes are generated in the gain spectrum determined by the active layer 23, this Fig.19 It is schematically shown in FIG. Note that Fig.19 Two longitudinal modes are shown: longitudinal mode A and longitudinal mode B. Then, in this case, it is assumed that the light absorbing material layer 71 is located in the minimum amplitude portion of the longitudinal mode A, but not in the minimum amplitude portion of the longitudinal mode B. Then, the mode loss in the longitudinal mode A is minimized, but the mode loss in the longitudinal mode B is large. Fig.19 , the mode loss of the longitudinal mode B is schematically illustrated by a solid line. Therefore, the longitudinal mode A is more likely to cause oscillation than the longitudinal mode B. Therefore, by using such a structure, that is, by controlling the position and period of the light absorbing material layer 71, a specific longitudinal mode can be stabilized and oscillation can be promoted. On the other hand, since the mode loss of other undesirable longitudinal modes will increase, the oscillation of other undesirable longitudinal modes can be suppressed.

[0313] As described above, in the light-emitting element of Example 10, since at least two light-absorbing material layers are formed inside the laminated structure, among the laser beams of various types of longitudinal modes that can be emitted from the surface-emitting laser element, the oscillation of the laser beam under the undesired longitudinal mode can be more effectively suppressed. As a result, the oscillation wavelength of the emitted laser beam can be more accurately controlled. In addition, even in the light-emitting element of Example 10, since the protrusion is included, the occurrence of diffraction loss can be reliably suppressed.

[0314] [Example 11]

[0315] Example 11 is a modification of Example 10. In Example 10, the light absorbing material layer 71 includes a compound semiconductor material having a narrower band gap than the compound semiconductor constituting the laminated structure 20. On the other hand, in Example 11, the ten light absorbing material layers 71 include a compound semiconductor material doped with an impurity, specifically, having a band gap of 1×10 19 / cm 3 The compound semiconductor material (specifically, n-GaN:Si) with an impurity concentration (impurity: Si) of 1.5 % is used. In Example 11, the oscillation wavelength λ0 is set to 515 nm. Note that the composition of the active layer 23 is In 0.3 Ga 0.7 N. In Example 11, m=1 and L Abs The value of is 107nm, the distance between the center in the thickness direction of the active layer 23 and the center in the thickness direction of the light absorbing material layer 71 adjacent to the active layer 23 is 53.5nm, and the thickness of the light absorbing material layer 71 is 3nm. Except for the above points, the configuration and structure of the light emitting element of Example 11 can be similar to the configuration and structure of the light emitting element of Example 10, so a detailed description thereof will be omitted. Note that among the ten light absorbing material layers 71, in some of the light absorbing material layers 71, m can be set to any integer greater than or equal to 2.

[0316] [Example 12]

[0317] Example 12 is also a variation of Example 10. In Example 12, the five light absorbing material layers (referred to as “first light absorbing material layers” for convenience) have the same structure as the light absorbing material layer 71 (that is, n-In 0.3 Ga 0.7 N) is a similar configuration. In addition, in Example 12, one light absorbing material layer (referred to as "second light absorbing material layer" for convenience) includes a transparent conductive material. Specifically, the second light absorbing material layer is also used as the second electrode 32 including ITO. In Example 12, the oscillation wavelength λ0 is set to 450nm. In addition, m=1 and 2 are set. When m=1, L AbsThe value of is 93.0nm, the distance between the center in the thickness direction of the active layer 23 and the center in the thickness direction of the first light absorbing material layer adjacent to the active layer 23 is 46.5nm, and the thickness of the five first light absorbing material layers is 3nm. That is, in the five first light absorbing material layers, , satisfies 0.9×{λ0 / (2·n eq )}≤L Abs ≤1.1×{λ0 / (2·n eq )}. In addition, in the first light absorbing material layer and the second light absorbing material layer adjacent to the active layer 23, m=2 is set. That is, 0.9×{(2·λ0) / (2·n eq )}≤L Abs ≤1.1×{(2·λ0) / (2·n eq The light absorption coefficient of a second light absorbing material layer also used as the second electrode 32 is 2000 cm -1 , the thickness is 30nm, and the distance from the active layer 23 to the second light absorbing material layer is 139.5nm. In addition to the above points, the configuration and structure of the light emitting element of Example 12 can be similar to the configuration and structure of the light emitting element of Example 10, so a detailed description thereof will be omitted. Note that among the five first light absorbing material layers, in some of the first light absorbing material layers, m can be set to any integer greater than or equal to 2. Note that, unlike Example 10, the number of light absorbing material layers 71 can be set to 1. In this case as well, the positional relationship between the second light absorbing material layer, which is also used as the second electrode 32, and the light absorbing material layer 71 needs to satisfy the following expression:

[0318] 0.9×{(m·λ0) / (2·n eq )}≤L Abs ≤1.1×{(m·λ0) / (2·n eq )}.

[0319] Although the present disclosure has been described above based on preferred examples, the present disclosure is not limited to these examples. The configuration and structure of the light-emitting element described in the examples are examples and can be appropriately changed, and the manufacturing method of the light-emitting element can be appropriately changed. In some cases, the light-emitting element can be a surface-emitting laser element that emits light from the first compound semiconductor layer through the first light-reflecting layer, and in this case, the second light-reflecting layer can be supported by the supporting substrate 49 via the bonding layer 48 (see the light-emitting element as a modification of Example 1). Fig. 20 and a modification of the light emitting element of Example 2 Fig.21 ). Furthermore, by appropriately selecting the bonding layer and the supporting substrate, the light emitting element can be a surface emitting laser element that emits light from the top surface of the second compound semiconductor layer through the second light reflecting layer.

[0320] Note that the present disclosure can also adopt the following configurations.

[0321] [A01] <<Light Emitting Component>>

[0322] A light emitting element, comprising:

[0323] A laminated structure, wherein a first compound semiconductor layer, an active layer, and a second compound semiconductor layer are laminated in the laminated structure, the first compound semiconductor layer includes a first surface and a second surface facing the first surface, the active layer faces the second surface of the first compound semiconductor layer, and the second compound semiconductor layer includes a first surface facing the active layer and a second surface facing the first surface;

[0324] a first electrode electrically connected to the first compound semiconductor layer; and

[0325] The second electrode and the second light reflecting layer are formed on the second surface of the second compound semiconductor layer, wherein

[0326] forming a protrusion on the first surface side of the first compound semiconductor layer,

[0327] forming a smooth layer at least on the protruding portion,

[0328] The protrusion and the smooth layer constitute the concave mirror part.

[0329] forming a first light reflecting layer on at least a portion of the smoothing layer, and

[0330] The second light reflecting layer has a flat shape.

[0331] [A02] The light emitting element according to [A01], wherein a value of surface roughness Ra1 of the smooth layer at an interface between the smooth layer and the first light reflecting layer is smaller than a value of surface roughness Ra2 of the protrusion at an interface between the protrusion and the smooth layer.

[0332] [A03] The light-emitting element according to [A02], wherein the value of the surface roughness Ra1 is less than or equal to 1.0 nm.

[0333] [A04] The light emitting element according to any one of [A01] to [A03], wherein an average thickness of the smooth layer at the top of the protrusion is thinner than an average thickness of the smooth layer at the edge of the protrusion.

[0334] [A05] The light-emitting element according to any one of [A01] to [A04], wherein the radius of curvature of the smoothing layer is 1×10 - 5 m to 1×10 -3 m.

[0335] [A06] A light-emitting element according to any one of [A01] to [A05], wherein the material constituting the smoothing layer is at least one material selected from the group consisting of a dielectric material, a spin-on glass-based material, a low-melting-point glass material, a semiconductor material, and a resin.

[0336] [B01] <<Method for manufacturing a light-emitting element: First aspect>>

[0337] A method for manufacturing a light emitting element, the method comprising the following steps:

[0338] forming a laminated structure in which a first compound semiconductor layer, an active layer, and a second compound semiconductor layer are laminated, the first compound semiconductor layer including a first surface and a second surface facing the first surface, the active layer facing the second surface of the first compound semiconductor layer, and the second compound semiconductor layer including a first surface facing the active layer and a second surface facing the first surface; then,

[0339] forming a second electrode and a second light reflecting layer on the second surface of the second compound semiconductor layer; thereafter,

[0340] forming a protrusion on the first surface side of the first compound semiconductor layer; then,

[0341] A smoothing layer is formed at least on the protruding portion, and then the surface of the smoothing layer is smoothed; thereafter,

[0342] A first light reflecting layer is formed on at least a portion of the smoothing layer, and a first electrode electrically connected to the first compound semiconductor layer is formed, wherein:

[0343] The protrusion and the smooth layer constitute a concave mirror portion, and

[0344] The second light reflecting layer has a flat shape.

[0345] [B02] The method for manufacturing a light-emitting element according to [B01], wherein the smoothing process on the surface of the smoothing layer is based on wet etching.

[0346] [B03] The method for manufacturing a light-emitting element according to [B01], wherein the smoothing process on the surface of the smoothing layer is based on dry etching.

[0347] [B04] A method for manufacturing a light-emitting element according to any one of [B01] to [B03], wherein a value of surface roughness Ra1 of the smooth layer at the interface between the smooth layer and the first light reflecting layer is smaller than a value of surface roughness Ra2 of the protrusion at the interface between the protrusion and the smooth layer.

[0348] [B05] The method for manufacturing a light-emitting element according to [B04], wherein the value of the surface roughness Ra1 is less than or equal to 1.0 nm.

[0349] [B06] The method for manufacturing a light emitting element according to any one of [B01] to [B05], wherein an average thickness of the smooth layer at the top of the protrusion is thinner than an average thickness of the smooth layer at the edge of the protrusion.

[0350] [B07] The method for manufacturing a light-emitting element according to any one of [B01] to [B06], wherein the radius of curvature of the smooth layer is 1×10 -5 m to 1×10 -3 m.

[0351] [B08] A method for manufacturing a light-emitting element according to any one of [B01] to [B07], wherein the material constituting the smoothing layer is at least one material selected from the group consisting of a dielectric material, a spin-on glass-based material, a low-melting-point glass material, a semiconductor material, and a resin.

[0352] [C01] <<Method for manufacturing a light-emitting element: Second aspect>>

[0353] A method for manufacturing a light emitting element, the method comprising the following steps:

[0354] forming a laminated structure in which a first compound semiconductor layer, an active layer, and a second compound semiconductor layer are laminated, the first compound semiconductor layer including a first surface and a second surface facing the first surface, the active layer facing the second surface of the first compound semiconductor layer, and the second compound semiconductor layer including a first surface facing the active layer and a second surface facing the first surface; then,

[0355] forming a second electrode and a second light reflecting layer on the second surface of the second compound semiconductor layer; thereafter,

[0356] forming a protrusion on the first surface side of the first compound semiconductor layer; then, smoothing the surface of the protrusion; then,

[0357] A first light reflecting layer is formed on at least a portion of the protrusion, and a first electrode electrically connected to the first compound semiconductor layer is formed, wherein:

[0358] The protrusion constitutes a concave mirror portion, and

[0359] The second light reflecting layer has a flat shape.

[0360] [C02] The method for manufacturing a light-emitting element according to [C01], wherein the smoothing process on the surface of the protrusion is based on wet etching.

[0361] [C03] The method for manufacturing a light-emitting element according to [C01], wherein the smoothing process on the surface of the protrusion is based on dry etching.

[0362] [D01] <<Light-emitting element having a first configuration>>

[0363] The light-emitting element according to any one of [A01] to [A06], wherein

[0364] The second compound semiconductor layer is provided with a current injection region and a current non-injection region surrounding the current injection region, and

[0365] The shortest distance D from the area centroid of the current injection area to the boundary between the current injection area and the current non-injection area CI Satisfies the following expression D CI ≥ω0 / 2,

[0366] in,

[0367] ω0 2 ≡(λ0 / π){L OR (R DBR -L OR )} 1 / 2

[0368] here,

[0369] λ0: wavelength of light mainly emitted from the light emitting element,

[0370] L OR : resonator length,

[0371] R DBR : The radius of curvature of the inner surface of the first light reflecting layer.

[0372] [D02] The light-emitting element according to [D01], further comprising

[0373] a mode loss action site which is provided on the second surface of the second compound semiconductor layer and constitutes a mode loss action region which acts on the increase or decrease of the oscillation mode loss, and

[0374] A second electrode is formed above the mode loss action site from the second surface of the second compound semiconductor layer, wherein

[0375] 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, and

[0376] The orthographic projection image of the mode loss effect region and the orthographic projection image of the current non-injection / external region overlap each other.

[0377] [D03] The light emitting element according to [D01] or [D02], wherein the radius r′ of the effective area of ​​the first light reflecting layer is DBR Satisfy ω0≤r'DBR ≤20·ω0.

[0378] [D04] The light-emitting element according to any one of [D01] to [D03], wherein D CI ≥ω0.

[0379] [D05] The light-emitting element according to any one of [D01] to [D04], wherein R DBR ≤1×10 -3 m.

[0380] [E01] <<Light-emitting element having a second configuration>>

[0381] The light-emitting element according to any one of [A01] to [A06] further includes:

[0382] a mode loss action site which is provided on the second surface of the second compound semiconductor layer and constitutes a mode loss action region which acts on the increase or decrease of the oscillation mode loss, and

[0383] The second electrode is formed above the mode loss action site from the second surface of the second compound semiconductor layer, wherein

[0384] 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, and

[0385] The orthographic projection image of the mode loss effect region and the orthographic projection image of the current non-injection / external region overlap each other.

[0386] [E02] A light-emitting element according to [E01], wherein the current non-injection / external region is located below the mode loss action region.

[0387] [E03] The light-emitting element according to [E01] or [E02], wherein:

[0388] When the area of ​​the projected image of the current injection region is S1 and the area of ​​the projected image of the current non-injection / inner region is S2, 0.01≤S1 / (S1+S2)≤0.7 is satisfied.

[0389] [E04] <<Light-emitting element having second configuration A>>

[0390] The light emitting element 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 implantation into the laminated structure.

[0391] [E05] The light-emitting element according to [E04], wherein the ion species is at least one ion selected from the group consisting of boron, protons, phosphorus, arsenic, carbon, nitrogen, fluorine, oxygen, germanium and silicon.

[0392] [E06] <<Light-emitting element having second configuration B>>

[0393] A light-emitting element according to any one of [E01] to [E05], wherein the current non-injection / internal region and the current non-injection / external region are formed by plasma irradiating the second surface of the second compound semiconductor layer, ashing the second surface of the second compound semiconductor layer, or reactive ion etching the second surface of the second compound semiconductor layer.

[0394] [E07] <<Light-emitting element having second configuration C>>

[0395] The light emitting element according to any one of [E01] to [E06], wherein the second light reflecting layer includes a region that reflects or scatters light from the first light reflecting layer toward the outside of the resonator structure including the first light reflecting layer and the second light reflecting layer.

[0396] [E08] A light-emitting element according to any one of [E04] to [E07], wherein when the optical distance from the active layer in the current injection region to the second surface of the second compound semiconductor layer is L2 and the optical distance from the active layer in the mode loss action region to the top surface of the mode loss action site is L0, L0>L2 is satisfied.

[0397] [E09] A light-emitting element according to any one of [E04] to [E08], wherein the generated laser beam having a higher-order mode diverges toward the outside of the resonator structure including the first light reflecting layer and the second light reflecting layer due to the mode loss action area, thereby increasing the oscillation mode loss.

[0398] [E10] A light-emitting element according to any one of [E04] to [E09], wherein the mode loss action site may include a dielectric material, a metal material, or an alloy material.

[0399] [E11] The light emitting element according to [E10], wherein the mode loss action site includes a dielectric material, and

[0400] The value of the optical thickness of the portion where the mode loss acts deviates from an integral multiple of 1 / 4 of the wavelength of light generated in the light emitting element.

[0401] [E12] The light emitting element according to [E10], wherein the mode loss action site includes a dielectric material, and

[0402] The optical thickness of the portion where the mode loss acts is an integral multiple of 1 / 4 of the wavelength of light generated in the light emitting element.

[0403] [E13] <<Light-emitting element having second configuration D>>

[0404] The light emitting element according to any one of [E01] to [E03], wherein a protrusion is formed on the second surface side of the second compound semiconductor layer, and

[0405] A mode loss action site is formed in a region surrounding the protruding portion of the second surface of the second compound semiconductor layer.

[0406] [E14] The light-emitting element according to [E13], wherein when the optical distance from the active layer in the current injection region to the second surface of the second compound semiconductor layer is L2 and the optical distance from the active layer in the mode loss action region to the top surface of the mode loss action site is L0, L0 is satisfied. <L2。

[0407] [E15] A light-emitting element according to [E13] or [E14], wherein the generated light having a higher-order mode is confined to a current injection region and a current non-injection / internal region due to a mode loss action region, thereby reducing oscillation mode loss.

[0408] [E16] A light-emitting element according to any one of [E13] to [E15], wherein the mode loss action site may include a dielectric material, a metal material, or an alloy material.

[0409] [E17] The light-emitting element according to any one of [E01] to [E16], wherein the second electrode includes a transparent conductive material.

[0410] [F01] <<Light-emitting element having a third configuration>>

[0411] The light emitting element according to any one of [A01] to [E17], wherein, in the laminated structure including the second electrode, at least two light absorbing material layers are formed parallel to a virtual plane occupied by the active layer.

[0412] [F02] The light-emitting element according to [F01], wherein at least four light-absorbing material layers are formed.

[0413] [F03] The light emitting element according to [F01] or [F02], wherein when the oscillation wavelength is λ0, the total equivalent refractive index of the two light absorbing material layers and a portion of the laminated structure located between the light absorbing material layers and the light absorbing material layers is n eq , and the distance between the light absorbing material layers is L Abs When 0.9×{(m·λ0) / (2·n eq)}≤L Abs ≤1.1×{(m·λ0) / (2·n eq )}. However, m is 1 or any integer greater than or equal to 2, including 1.

[0414] [F04] The light emitting element according to any one of [F01] to [F03], wherein the thickness of the light absorbing material layer is less than or equal to λ0 / (4·n eq ).

[0415] [F05] The light emitting element according to any one of [F01] to [F04], wherein the light absorbing material layer is located at a minimum amplitude portion generated in a standing wave of light formed inside the laminated structure.

[0416] [F06] The light-emitting element according to any one of [F01] to [F05], wherein the active layer is located at a maximum amplitude portion generated in a standing wave of light formed inside the laminated structure.

[0417] [F07] The light emitting element according to any one of [F01] to [F06], wherein a light absorption coefficient of the light absorbing material layer is two times or more a light absorption coefficient of a compound semiconductor constituting the laminated structure.

[0418] [F08] A light-emitting element according to any one of [F01] to [F07], wherein the light-absorbing material layer includes at least one material selected from the group consisting of a compound semiconductor material having a band gap narrower than that of the compound semiconductor constituting the laminated structure, a compound semiconductor material doped with impurities, a transparent conductive material, and a light-reflecting layer constituting material having light-absorbing properties.

[0419] Reference Symbols List

[0420] 11 base plate

[0421] 11a First surface of substrate

[0422] 11b Second surface of the substrate

[0423] 20 Laminated structure

[0424] 21. First compound semiconductor layer

[0425] 21a First surface of the first compound semiconductor layer

[0426] 21b The second surface of the first compound semiconductor layer

[0427] 22. Second compound semiconductor layer

[0428] 22a First surface of the second compound semiconductor layer

[0429] 22b The second surface of the second compound semiconductor layer

[0430] 23 Active layer (light-emitting layer)

[0431] 31. First electrode

[0432] 32. Second electrode

[0433] 33 pad electrode

[0434] 34 Insulation layer (current limiting layer)

[0435] 34A Opening provided in insulating layer (current limiting layer)

[0436] 41 first light reflecting layer

[0437] 41a Inner surface of the first light reflecting layer

[0438] 41b Effective area of ​​the first light reflecting layer

[0439] 42 second light reflecting layer

[0440] 43, 45, 46, 47 protrusions

[0441] 44 Smoothing Layer

[0442] 48 Bonding layer

[0443] 49 Support substrate

[0444] 51 Current injection area

[0445] 52 Current non-injection / internal region

[0446] 53 Current non-injection / external region

[0447] 54 Mode loss action site (mode loss action layer)

[0448] 54A, 54B are openings formed at the site where the mode loss occurs.

[0449] 55 Mode loss action area

[0450] 61A current injection area

[0451] 61B Current non-injection region

[0452] 61C Boundary between current injection region and current non-injection region

[0453] 71 light absorbing material layer

[0454] 81 Resist layer

[0455] 82 Protrusion of resist layer

Claims

1. A light-emitting element, comprising: A laminated structure, wherein a first compound semiconductor layer, an active layer, and a second compound semiconductor layer are laminated therein, the first compound semiconductor layer comprising a first surface and a second surface facing the first surface, the active layer facing the second surface of the first compound semiconductor layer, and the second compound semiconductor layer comprising a first surface facing the active layer and a second surface facing the first surface of the second compound semiconductor layer; a first electrode electrically connected to the first compound semiconductor layer; as well as A second electrode and a second light reflecting layer are formed on a second surface of the second compound semiconductor layer, wherein: a protrusion formed on the first surface side of the first compound semiconductor layer, a smoothing layer formed at least on the protrusion, the protrusion and the smoothing layer constitute a concave mirror portion, wherein the surface of the smoothing layer is smoothed, a first light reflecting layer formed on at least a portion of the smoothed surface of the smoothing layer, and The second light reflecting layer has a flat shape, wherein a value of the surface roughness Ra1 of the smooth layer at the interface between the smooth layer and the first light reflecting layer is smaller than a value of the surface roughness Ra2 of the protrusion at the interface between the protrusion and the smooth layer, The average thickness of the smooth layer at the top of the protrusion is thinner than the average thickness of the smooth layer at the edge of the protrusion.

2. The light-emitting element according to claim 1, wherein The value of the surface roughness Ra1 is less than or equal to 1.0 nm.

3. The light-emitting element according to claim 1, wherein The curvature radius of the smooth layer is 1×10 -5 m to 1×10 -3 m.

4. The light-emitting element according to claim 1, wherein The material constituting the smoothing layer is at least one material selected from the group consisting of a dielectric material, a spin-on-glass based material, a low-melting-point glass material, a semiconductor material, and a resin.

5. A method for manufacturing a light emitting element, the method comprising the following steps: forming a laminated structure in which a first compound semiconductor layer, an active layer, and a second compound semiconductor layer are laminated, the first compound semiconductor layer including a first surface and a second surface facing the first surface, the active layer facing the second surface of the first compound semiconductor layer, and the second compound semiconductor layer including a first surface facing the active layer and a second surface facing the first surface of the second compound semiconductor layer; Then, forming a second electrode and a second light reflecting layer on the second surface of the second compound semiconductor layer; After that, forming a protrusion on the first surface side of the first compound semiconductor layer; Then, forming a smoothing layer at least on the protruding portion, and then smoothing the surface of the smoothing layer; After that, A first light reflecting layer is formed on at least a portion of the surface of the smooth layer, and a first electrode electrically connected to the first compound semiconductor layer is formed, wherein: The protrusion and the smooth layer constitute a concave mirror portion, and The second light reflecting layer has a flat shape, wherein a value of the surface roughness Ra1 of the smooth layer at the interface between the smooth layer and the first light reflecting layer is smaller than a value of the surface roughness Ra2 of the protrusion at the interface between the protrusion and the smooth layer, The average thickness of the smooth layer at the top of the protrusion is thinner than the average thickness of the smooth layer at the edge of the protrusion.

6. The method for manufacturing a light emitting element according to claim 5, wherein: The smoothing process on the surface of the smoothing layer is based on wet etching.

7. The method for manufacturing a light emitting element according to claim 5, wherein: The smoothing process on the surface of the smoothing layer is based on dry etching.

8. The method for manufacturing a light emitting element according to claim 5, wherein: The value of the surface roughness Ra1 is less than or equal to 1.0 nm.

9. The method for manufacturing a light emitting element according to claim 5, wherein: The curvature radius of the smooth layer is 1×10 -5 m to 1×10 -3 m.

10. The method for manufacturing a light emitting element according to claim 5, wherein: The material constituting the smoothing layer is at least one material selected from the group consisting of a dielectric material, a spin-on-glass based material, a low-melting-point glass material, a semiconductor material, and a resin.

11. A method for manufacturing a light emitting element, the method comprising the following steps: forming a laminated structure in which a first compound semiconductor layer, an active layer, and a second compound semiconductor layer are laminated, the first compound semiconductor layer including a first surface and a second surface facing the first surface, the active layer facing the second surface of the first compound semiconductor layer, and the second compound semiconductor layer including a first surface facing the active layer and a second surface facing the first surface of the second compound semiconductor layer; Then, forming a second electrode and a second light reflecting layer on the second surface of the second compound semiconductor layer; After that, forming a protrusion on the first surface side of the first compound semiconductor layer; and then smoothing the surface of the protrusion; Then, A first light reflecting layer is formed on at least a portion of the surface of the protrusion, and a first electrode electrically connected to the first compound semiconductor layer is formed, wherein: The protrusion constitutes a concave mirror portion, and The second light reflecting layer has a flat shape, wherein a value of the surface roughness Ra1 of the smooth layer at the interface between the smooth layer and the first light reflecting layer is smaller than a value of the surface roughness Ra2 of the protrusion at the interface between the protrusion and the smooth layer, The average thickness of the smooth layer at the top of the protrusion is thinner than the average thickness of the smooth layer at the edge of the protrusion.

12. The method for manufacturing a light emitting element according to claim 11, wherein: The smoothing process on the surface of the protrusion is based on wet etching.

13. The method for manufacturing a light emitting element according to claim 11, wherein: The smoothing process on the surface of the protrusion is based on dry etching.

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