Surface light emitting element, light emitting device, and method for manufacturing the surface light emitting element

Abstract

This surface light emitting element comprises: a substrate that has a first surface and a second surface opposed to the first surface; an epitaxial growth layer that has a first semiconductor layer of a first conductivity type, an active layer and a second semiconductor layer of a second conductivity type all of which are sequentially laminated on the second surface by epitaxial growth and that is distributed in the thickness direction and in the resonator length direction; an electrode that is electrically connected to the first semiconductor layer; a current injection region that is formed on the surface of the second semiconductor layer opposite to the substrate and that is electrically connected to the second semiconductor layer and further has an optical transparency; a first reflection layer that is formed on the first surface in accordance with the position of a predetermined thickness of the epitaxial growth layer and that has a curved mirror structure; and a second reflection layer that is formed on the surface of the current injection region opposite to the second semiconductor layer.

Description

[Technical Field]

[0001] The present disclosure relates to a surface light emitting element, a light emitting device, and a method for manufacturing a surface light emitting element. [Background technology]

[0002] For example, Non-Patent Document 1 discloses a GaN-based vertical cavity surface emitting laser (VCSEL). In a VCSEL, an n-type GaN layer, an active layer, and a p-type GaN layer are stacked on an n-type GaN substrate. The n-type GaN layer, the active layer, and the p-type GaN layer are all formed by epitaxial growth. An n-side reflective layer (DBR: Distributed Bragg Reflector) is formed under the n-type GaN substrate. A p-side reflective layer (DBR) is formed on the p-type GaN layer. An n-side metal electrode is electrically connected to the n-type GaN layer, and a p-side metal electrode is electrically connected to the p-type GaN layer. [Prior art documents] [Patent documents]

[0003] [Non-Patent Document 1] SCIENTIFIC REPORTS | (2018) 8:10350 |DOI:10.1038 / s41598-018-28418-6 Summary of the Invention

[0004] In the manufacture of VCSELs, the epitaxially grown layer is formed to a uniform thickness across the GaN wafer surface. If the thickness of the epitaxially grown layer deviates from the set value, the threshold current density changes, leading to deterioration of the VCSEL characteristics. On the other hand, the tilt of the reflective layer of a VCSEL has a significant effect on its characteristics. For example, a tilt of just 0.001 degrees in the reflective layer significantly increases optical loss, including diffraction loss.

[0005] For this reason, it is desirable to effectively suppress or prevent optical losses, including diffraction losses, in VCSELs.

[0006] A surface-emitting device according to a first embodiment of the present disclosure comprises a substrate having a first surface and a second surface opposite the first surface, an epitaxially grown layer having a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type sequentially stacked by epitaxial growth on the second surface, the epitaxially grown layer having a distribution in thickness and cavity length, an electrode electrically connected to the first semiconductor layer, a current injection region formed on the surface of the second semiconductor layer opposite the substrate and electrically connected to the second semiconductor layer, the current injection region having optical transparency, a first reflective layer formed on the first surface corresponding to a position at a predetermined thickness of the epitaxially grown layer and having a curved mirror structure, and a second reflective layer formed on the surface of the current injection region opposite the second semiconductor layer.

[0007] A light-emitting device according to a second embodiment of the present disclosure comprises a plurality of arranged surface-emitting elements, each of which comprises a substrate having a first surface and a second surface opposite to the first surface, an epitaxial growth layer having a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type sequentially stacked by epitaxial growth on the second surface, the epitaxial growth layer having a distribution in thickness and cavity length, an electrode electrically connected to the first semiconductor layer, a current injection region formed on the surface of the second semiconductor layer opposite the substrate and electrically connected to the second semiconductor layer, the current injection region having optical transparency, a first reflective layer formed on the first surface corresponding to a position at a predetermined thickness of the epitaxial growth layer and having a curved mirror structure, and a second reflective layer formed on the surface of the current injection region opposite the second semiconductor layer.

[0008] A method for manufacturing a surface-emitting device according to a third embodiment of the present disclosure includes sequentially stacking a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type by epitaxial growth on a second surface opposite the first surface of a substrate, forming an epitaxially grown layer having a distribution in thickness and cavity length, forming an electrode electrically connected to the first semiconductor layer, forming a current injection region electrically connected to the second semiconductor layer and having optical transparency on the surface of the second semiconductor layer opposite the substrate, forming a second reflective layer on the surface of the current injection region opposite the second semiconductor layer, measuring the thickness of the epitaxially grown layer, and forming a first reflective layer having a curved mirror structure at a predetermined position on the first surface. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a main part of a surface light emitting element and a light emitting device according to a first embodiment of the present disclosure. [Figure 2] 2 is a schematic cross-sectional view of a state in which an epitaxial growth layer is formed on a substrate (here, a wafer) in the manufacturing process of the surface light emitting device shown in FIG. [Figure 3] 3 is a perspective view of a main part illustrating the correspondence between a part of an epitaxially grown layer that is used as a surface light emitting device from the substrate shown in FIG. 2 and a first reflective layer. FIG. [Figure 4] 4 is a cross-sectional view of a main part illustrating the correspondence between a part of the epitaxial growth layer shown in FIG. 3 and a first reflective layer. FIG. [Figure 5] 2 is a diagram showing the relationship between the deviation of the thickness of the epitaxially grown layer from the set value and the threshold current density in the surface light emitting device shown in FIG. [Figure 6] 4 is a flowchart illustrating an example of a manufacturing method for a surface light emitting device according to the first embodiment. [Figure 7] 5 is a cross-sectional view of a main part of a surface light emitting element and a light emitting device according to a second embodiment of the present disclosure, corresponding to FIG. 4. FIG. [Figure 8] 10 is a cross-sectional view of a main part of a surface light emitting element and a light emitting device according to a third embodiment of the present disclosure, corresponding to FIG. 4. FIG. [Figure 9]10A to 10C are cross-sectional views illustrating steps in a method for manufacturing an epitaxially grown layer of a surface light emitting element and a light emitting device according to a fourth embodiment of the present disclosure. [Figure 10] 10A to 10C are cross-sectional views corresponding to FIG. 9 illustrating steps in a method for manufacturing an epitaxially grown layer of a surface light emitting element and a light emitting device according to a fifth embodiment of the present disclosure. [Figure 11] 10A to 10C are cross-sectional views corresponding to FIG. 9 illustrating steps in a method for manufacturing an epitaxially grown layer of a surface light emitting element and a light emitting device according to a sixth embodiment of the present disclosure. [Figure 12] 10A to 10C are cross-sectional views corresponding to FIG. 9 illustrating steps in a method for manufacturing an epitaxially grown layer of a surface light emitting element and a light emitting device according to a seventh embodiment of the present disclosure. [Figure 13] 13A to 13C are cross-sectional views corresponding to FIG. 9 illustrating steps in a method for manufacturing an epitaxially grown layer of a surface light emitting element and a light emitting device according to an eighth embodiment of the present disclosure. [Figure 14A] FIG. 14 is a schematic plan view illustrating the arrangement of the insulators shown in FIG. 13 in the plane of a substrate (here, a wafer). [Figure 14B] FIG. 14B is a schematic plan view corresponding to FIG. 14A and illustrating an arrangement of insulators according to a first modified example of the eighth embodiment. [Figure 14C] FIG. 14B is a schematic plan view corresponding to FIG. 14A and illustrating an arrangement of insulators according to a second modified example of the eighth embodiment. [Figure 14D] FIG. 14B is a schematic plan view corresponding to FIG. 14A and illustrating an arrangement of insulators according to a third modified example of the eighth embodiment. [Figure 14E] FIG. 14B is a schematic plan view corresponding to FIG. 14A and illustrating an arrangement of insulators according to a fourth modified example of the eighth embodiment. [Figure 14F] FIG. 14B is a schematic plan view corresponding to FIG. 14A and illustrating an arrangement of insulators according to a fifth modified example of the eighth embodiment. [Figure 15] 13A to 13C are cross-sectional views corresponding to FIG. 9 illustrating steps in a method for manufacturing an epitaxially grown layer of a surface light emitting element and a light emitting device according to a ninth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The description will be made in the following order. 1. First embodiment In the first embodiment, an example in which the present technology is applied to a surface light emitting element and a light emitting device will be described. Here, the basic structure and manufacturing process of the surface light emitting element will be described. 2. Second embodiment The second embodiment is an example of application of the present technology, and describes a first example in which the structure of the epitaxially grown layer of the surface light emitting element and light emitting device according to the first embodiment is changed. 3. Third embodiment The third embodiment is an example of application of the present technology, and describes a second example in which the structure of the epitaxially grown layer of the surface light emitting element and light emitting device according to the first embodiment is changed. 4. Fourth embodiment The fourth embodiment is an example in which the present technology is applied, and describes a first example of a specific method for manufacturing the epitaxially grown layer of the surface light emitting element and the light emitting device according to the first embodiment. 5. Fifth Embodiment The fifth embodiment is an example of application of the present technology, and will describe a second example of a specific method for manufacturing the epitaxially grown layer of the surface light emitting element and light emitting device according to the first embodiment. 6. Sixth Embodiment The sixth embodiment is an example in which the present technology is applied, and will describe a third example of a specific method for manufacturing the epitaxially grown layer of the surface light emitting element and light emitting device according to the first embodiment. 7. Seventh Embodiment The seventh embodiment is an example in which the present technology is applied, and will describe a fourth example of a specific method for manufacturing the epitaxially grown layer of the surface light emitting element and light emitting device according to the first embodiment. 8. Eighth Embodiment The eighth embodiment is an example of application of the present technology, and describes a fifth example of a specific method for manufacturing an epitaxially grown layer of the surface light emitting element and the light emitting device according to the first embodiment. Several modified examples will also be described here. 9. Ninth Embodiment The ninth embodiment is an example of application of the present technology, and describes a sixth example of a specific method for manufacturing the epitaxially grown layer of the surface light emitting element and light emitting device according to the first embodiment. 10. Other embodiments

[0011] <1. First embodiment> A surface light emitting element 1 and a light emitting device 10 according to a first embodiment of the present disclosure will be described with reference to FIGS.

[0012] Here, the arrow X direction shown in the drawings indicates one planar direction of the surface light emitting device 1 placed on a flat surface for convenience. The arrow Y direction indicates another planar direction perpendicular to the arrow X direction. The arrow Z direction indicates the upward direction perpendicular to the arrow X and arrow Y directions. In other words, the arrow X direction, arrow Y direction, and arrow Z direction exactly coincide with the X-axis direction, Y-axis direction, and Z-axis direction, respectively, of a three-dimensional coordinate system. Note that these directions are shown to facilitate understanding of the description and are not intended to limit the directions of the present technology.

[0013] [Configuration of surface light emitting element 1] (1) Overall structure of the surface light emitting device 1 FIG. 1 shows an example of a vertical cross-sectional configuration of a surface light emitting device 1. As shown in FIG. The surface light emitting device 1 according to the first embodiment is configured as a VCSEL. The surface light emitting device 1 includes, as main components, a substrate 2, an epitaxial growth layer 3, a first reflective layer 8, and a second reflective layer 9. The epitaxial growth layer 3 includes a first semiconductor layer 31, an active layer 32, and a second semiconductor layer 33. The surface light emitting element 1 also includes a constriction region 4 and a current injection region 5. The surface light emitting element 1 further includes a first electrode 6 and a second electrode 7 formed thereon.

[0014] (2) Configuration of board 2 In the first embodiment, the surface light emitting device 1 is configured as, for example, a GaN-based VCSEL. Therefore, a GaN substrate of a first conductivity type is used for the substrate 2. For example, the first conductivity type is "n-type," and the substrate 2 is an n-type GaN substrate. The lower surface of the substrate 2 in the figure is the first surface 2A. The upper surface of the substrate 2 opposite to the first surface 2A is the second surface 2B. Here, the substrate 2 is a "wafer" when a plurality of surface light emitting devices 1 are simultaneously manufactured in the manufacture of the surface light emitting device 1. Also, in the manufacture of the surface light emitting device 1, after the wafer is diced through a dicing process, the substrate 2 is a "chip (or die)."

[0015] (3) Structure of the first semiconductor layer 31 of the epitaxial growth layer 3 The first semiconductor layer 31 of the epitaxial growth layer 3 is deposited by epitaxial growth on the second surface 2B of the substrate 2. The second surface 2B is a plane extending in the directions of the arrows X and Y. When viewed from the surface direction of this second surface 2B (hereinafter simply referred to as "in a side view"), the first semiconductor layer 31 is deposited on the second surface 2B in the direction of the arrow Z. The first semiconductor layer 31 is used as a cladding layer. The first semiconductor layer 31 is made of, for example, GaN of a first conductivity type (n-type GaN). The first semiconductor layer 31 is formed to a thickness of, for example, 100 nm or more and 10 μm or less.

[0016] (4) Structure of the active layer 32 of the epitaxial growth layer 3 The active layer 32 is laminated on the first semiconductor layer 31 by epitaxial growth. The active layer 32 is formed on the surface of the first semiconductor layer 31 opposite to the substrate 2. The active layer 32 is a light-emitting layer. The active layer 32 has a structure in which a plurality of barrier layers and quantum well layers are alternately laminated. The active layer 32 is mainly composed of, for example, GaInN. The active layer 32 is formed to a thickness of, for example, 1 nm or more and 50 nm or less. Also, quantum wires or quantum dots may be used instead of the quantum well layer in the active layer 32. Furthermore, the active layer 32 may be configured as a strain-compensated quantum well.

[0017] (5) Configuration of the second semiconductor layer 33 of the epitaxial growth layer 3 The second semiconductor layer 33 of the epitaxial growth layer 3 is laminated by epitaxial growth on the active layer 32. The second semiconductor layer 33 is formed on the surface of the active layer 32 opposite to the first semiconductor layer 31 side. The second semiconductor layer 33 is used as a cladding layer. The second semiconductor layer 33 is formed, for example, from GaN of a second conductivity type. The second conductivity type is "p-type," which is the opposite conductivity type to the first conductivity type. Therefore, the second semiconductor layer 33 is p-type GaN. The second semiconductor layer 33 is formed to a thickness of, for example, 10 nm or more and 250 nm or less.

[0018] (6) Structure of epitaxial growth layer 3 In the first embodiment, the epitaxial growth layer 3 has the same layered structure on the second surface 2B of the substrate 2, and is formed to a non-uniform thickness on the second surface 2B. That is, the surface light emitting device 1 has a distribution of differences in the thickness of the epitaxial growth layer 3 on the second surface 2B, and further has a distribution of differences in the cavity length according to the thickness distribution.

[0019] Fig. 2 shows a schematic longitudinal cross-sectional structure of a wafer-state substrate 2 in the manufacturing process of the surface light emitting device 1. Fig. 3 shows a schematic three-dimensional structure of the wafer-state substrate 2 shown in Fig. 2. Fig. 4 shows a schematic longitudinal cross-sectional structure of the surface light emitting device 1 manufactured from the epitaxial growth layer 3 in the region indicated by the symbol A in Figs. 2 and 3.

[0020] 2 and 3, in the process of manufacturing the surface light emitting device 1, an epitaxial growth layer 3 for manufacturing a plurality of surface light emitting devices 1 is formed on a single wafer-like substrate 2. Here, the thickness of the epitaxial growth layer 3 is formed to be non-uniform within the second surface 2B of the substrate (wafer) 2.

[0021] Each of the multiple layers constituting the epitaxial growth layer 3, the first semiconductor layer 31, the active layer 32, and the second semiconductor layer 33, is formed to a non-uniform thickness, and the epitaxial growth layer 3 is formed to a non-uniform thickness as a whole. In other words, the interface of the layered structure of the epitaxial growth layer 3 is formed in a linear shape inclined with respect to the second surface 2B in side view. To explain in more detail, as shown in particular in FIGS. 1 and 4 , the interface between the first semiconductor layer 31 and the active layer 32 and the interface between the active layer 32 and the second semiconductor layer 33 are both formed in a linear shape inclined with respect to the second surface 2B.

[0022] At least one single layer of the first semiconductor layer 31, the active layer 32, and the second semiconductor layer 33 may be formed to have a non-uniform thickness, and the epitaxially grown layer 3 may be formed to have a non-uniform thickness as a whole.

[0023] The surface light emitting device 1 shown in Fig. 4 is provided with a selected epitaxial growth layer 3 in the region marked with the symbol A and surrounded by a dashed line, selected from among the epitaxial growth layers 3 having a non-uniform thickness. In the region marked with the symbol A and surrounded by a dashed line, the epitaxial growth layer 3 is formed to a predetermined set thickness. This set thickness will be described later.

[0024] 3 , in the first embodiment, a range dx in which the thickness of the epitaxial growth layer 3 increases at a constant rate is selected in the direction of the arrow X, and this selected epitaxial growth layer 3 is used to manufacture the surface-emitting device 1. Here, a range dy in which the thickness of the epitaxial growth layer 3 does not change is selected in the direction of the arrow Y. That is, when viewed from the direction of the arrow Z (hereinafter simply referred to as "in a plan view"), the surface-emitting device 1 is constructed within the ranges dx and dy of the epitaxial growth layer 3. For example, when the second reflective layer 9 is formed in a circular shape with a diameter φ in a plan view, the second reflective layer 9 is formed within the ranges dx and dy of the epitaxial growth layer 3 (φ≦dx×dy).

[0025] Note that the surface light emitting device 1 may be manufactured in a range dx where the amount of change in the thickness of the epitaxial growth layer 3 decreases steadily. Furthermore, the surface light emitting device 1 may be manufactured in a range dx where the amount of change in the thickness of the epitaxial growth layer 3 increases steadily and in a range dy where the amount of change in the thickness of the epitaxial growth layer 3 increases or decreases steadily. Similarly, the surface light emitting device 1 may be manufactured in a range dx where the amount of change in the thickness of the epitaxial growth layer 3 decreases steadily and in a range dy where the amount of change in the thickness of the epitaxial growth layer 3 increases or decreases steadily.

[0026] FIG. 5 shows the relationship between the deviation in thickness of the epitaxially grown layer 3 and the low threshold current density. The horizontal axis represents the deviation in thickness of the epitaxially grown layer 3. The vertical axis represents the low threshold current density (J th [kA / cm 2 ]). The center of the horizontal axis represents a deviation of "0" from the predetermined set value of the thickness of the epitaxial growth layer 3. At a deviation of "0", the low threshold current density is at its minimum. As the thickness of the epitaxial growth layer 3 is shifted in the direction of increasing thickness (to the right) from a deviation of "0", the low threshold current density increases. Similarly, as the thickness of the epitaxial growth layer 3 is shifted in the direction of decreasing thickness (to the left) from a deviation of "0", the low threshold current density increases.

[0027] The difference in optical thickness of the epitaxially grown layer 3 corresponds to the spacing between two or more longitudinal modes of the oscillation wavelength of the surface light emitting element 1 that are shifted from each other. For example, when the cavity length of the surface-emitting device 1 is set to, for example, 10 μm or more and 20 μm or less, the longitudinal mode spacing is approximately 1 nm or more and 4 nm or less. If the cavity length is 20 μm and the longitudinal mode spacing is approximately 1 nm, the thickness of the epitaxial growth layer 3 will have a fluctuation range equivalent to 1 nm. Within this fluctuation range, there exists a thickness that is equivalent to the deviation amount of the epitaxial growth layer 3 of "0". In the above example, when the resonator is made of a material with a refractive index of "2", the fluctuation width of the thickness of the epitaxially grown layer 3 is 0.5 nm.

[0028] Therefore, by setting such an optical film thickness difference in the epitaxial growth layer 3, it is possible to select the thickness of the epitaxial growth layer 3 at which the low threshold current density becomes the minimum value. Furthermore, if an optical thickness difference ranging from several times to several tens of times can be generated in the epitaxially grown layer 3, it becomes possible to reliably select the thickness of the epitaxially grown layer 3 at which the low threshold current density becomes the minimum value.

[0029] Here, the epitaxial growth layer 3 is not limited to GaN, but can be formed of at least one material selected from the group consisting of InGaN, AlGaN, AlGaInN, GaAs, AlGaAs, AlAs, InGaAs, AlInGaP, InGaP, InP, InAlAs, AlInGaAs, AlGaAsP, InGaAs, InGaSb, and AlGaSb.

[0030] (7) Configuration of constriction region 4 1, the constriction region 4 is formed around the active layer 32 in the epitaxial growth layer 3. The constriction region 4 is configured as a current confinement region and an optical confinement region here. In the first embodiment, the constriction region 4 is formed by implanting, for example, boron around the active layer 32 using an ion implantation method and then passivating the implanted ions. The narrowed region 4 may be made of an insulator or a dielectric material.

[0031] (8) Configuration of current injection region 5 The current injection region 5 is formed in the second semiconductor layer 33. The current injection region 5 is stacked on the surface of the second semiconductor layer 33 opposite to the substrate 2. The current injection region 5 is electrically connected to the second semiconductor layer 33. In a plan view, the current injection region 5 is formed at least on the second semiconductor layer 33 in a region surrounded by the narrowing region 4, and further extends over the narrowing region 4. The current injection region 5 is conductive and optically transparent and is made of a transparent electrode material such as ITO (Indium Tin Oxide).

[0032] (9) Configuration of the first electrode 6 and the second electrode 7 The first electrode 6 is formed on the first semiconductor layer 31 exposed by removing a portion of the periphery of the epitaxial growth layer 3. The first electrode 6 is configured as an n-side metal electrode and is electrically connected to the first semiconductor layer 31. The second electrode 7 is formed on the constriction region 4 and on the current injection region 5. The second electrode 7 is configured as a p-side metal electrode and is electrically connected to the current injection region 5. In other words, the second electrode 7 is electrically connected to the second semiconductor layer 33 with the current injection region 5 interposed therebetween.

[0033] (10) Configuration of the first reflective layer 8 The first reflective layer 8 is formed on the first surface 2A of the substrate 2. The first reflective layer 8 has a curved mirror structure (concave mirror structure) that curves further downward from the first surface 2A of the substrate 2. Here, the first reflective layer 8 is made of a dielectric DBR in which, for example, multiple layers of Ta2O5 and SiO2 are alternately stacked.

[0034] The first reflective layer 8 is disposed at a position where the epitaxial growth layer 3 has a predetermined thickness setting, i.e., where the thickness deviation is "0" and the low threshold current density is at its minimum. Here, the optical axis of the first reflective layer 8 coincides with the position where the epitaxial growth layer 3 has a deviation of "0." This allows the light reflected by the first reflective layer 8 to be focused on the active layer 32, even when the epitaxial growth layer 3 has a non-uniform thickness. That is, in the surface light emitting device 1, diffraction loss can be effectively suppressed or prevented.

[0035] As described above, the required optical thickness difference of the epitaxially grown layer 3 is set to the longitudinal mode spacing (Δλ) in the surface light emitting device 1. The minimum value of the low threshold current density exists at this longitudinal mode spacing (Δλ). For example, when the longitudinal mode spacing Δλ is 1.2 nm or more and 2.0 nm or less, or 1 nm or more and 5 nm or less, the optical film thickness difference should be at least 0.5 nm, preferably more than 2.5 nm. Therefore, if there is an optical film thickness difference of about 2.5 nm within a given region, it is possible to find the optimum film thickness location, for example, by measurement. For this reason, one embodiment can be considered in which the reflective layer of a flat mirror structure (plane mirror structure) is tilted. Various examples that satisfy these conditions are shown below. 1. When the substrate (chip in this case) spacing is as small as 10 μm When the required optical film thickness difference is large, 50 nm, and the distance between the substrates 2 is small, 10 μm, the tilt angle becomes larger than 0.3 degrees. 2. When the gap between the two substrates is as small as 10 μm When the required optical film thickness difference is as small as 0.5 nm and the distance between the substrates 2 is as small as 10 μm, the tilt angle becomes larger than 0.003 degrees. 3. When the gap between the two substrates is medium, at 50 μm When the required optical film thickness difference is small, 0.5 nm, and the distance between the substrates 2 is medium, 50 μm, the tilt angle becomes larger than 0.0006 degrees. 4. When the distance between two boards is as large as 5cm (2 inches) If the required optical film thickness difference is as small as 0.5 nm and the distance between the two substrates is as large as 5 cm, the tilt angle is 6 × 10 -7 It becomes larger than the degree.

[0036] That is, in the examples of 3. and 4. above, the tilt angle can be made 0.001 degrees or less, so that the influence of optical losses including diffraction losses can be almost ignored.

[0037] The second reflective layer 9 is formed on the current injection region 5. The second reflective layer 9 has a flat mirror structure. Here, the second reflective layer 9 is made of a dielectric DBR, similar to the first reflective layer 8. At least one of the first reflective layer 8 and the second reflective layer 9 may be formed of a semiconductor DBR.

[0038] [Configuration of Light-Emitting Device 10] Although the overall configuration of the light emitting device 10 is not shown, it is constructed by arranging surface light emitting elements 1 shown in Fig. 1 in at least one of the directions of arrow X and arrow Y. The light emitting device 10 can be used as a light source for application devices such as optical storage, laser printers, projectors, displays, solid-state illuminators, optical communication devices, and biosensors.

[0039] [Method of manufacturing the surface light emitting element 1] The above-described surface light emitting device 1 is manufactured by the following manufacturing method. Figure 6 shows a flowchart explaining the manufacturing method of the surface light emitting device 1. The procedure will be briefly explained below.

[0040] First, the substrate 2 is prepared (step S1). The substrate 2 has a first surface 2A and a second surface 2B opposite to the first surface 2A.

[0041] Next, an epitaxial growth layer 3 is formed by epitaxial growth on the second surface 2B of the substrate 2 (step S2). The epitaxial growth layer 3 is formed by sequentially stacking a first semiconductor layer 31, an active layer 32, and a second semiconductor layer 33. This epitaxial growth layer 3 has a non-uniform thickness, which results in a distribution in the cavity length of the completed surface-emitting device 1. Furthermore, a narrowing region 4 is formed in the epitaxial growth layer 3 . A specific method for manufacturing the epitaxially grown layer 3 having a non-uniform thickness will be explained in the fourth embodiment and thereafter.

[0042] Next, a current injection region 5 is formed on the second semiconductor layer 33 of the epitaxial growth layer 3 (step S3). The current injection region 5 has optical transparency and is electrically connected to the second semiconductor layer 33. Subsequently, a second electrode 7 is formed in the current injection region 5 (step S4). The second electrode 7 is electrically connected to the second semiconductor layer 33 with the current injection region 5 interposed therebetween.

[0043] Next, the second reflective layer 9 is formed on the current injection region 5 including on the second electrode 7 (step S5). Here, the second reflective layer 9 is formed of a dielectric DBR.

[0044] Next, the second reflective layer 9, the current injection region 5 and a part of the epitaxially grown layer 3 are processed into a mesa shape (step S6). A part of the epitaxially grown layer 3 is processed until the surface of the first semiconductor layer 31 is exposed. Subsequently, the first electrode 6 is formed on the exposed surface of the first semiconductor layer 31 (step S7). The first electrode 6 is electrically connected to the first semiconductor layer 31.

[0045] Next, the thickness of the epitaxial growth layer 3 is measured (step S8). Here, the thickness of the epitaxial growth layer 3 that is a predetermined set value is measured. More specifically, the thickness of the epitaxial growth layer 3 that has a deviation of "0" from the predetermined set value, or the thickness of the epitaxial growth layer 3 that has a minimum low threshold current density, is measured.

[0046] Next, a first reflective layer 8 is formed on the first surface 2A of the substrate 2 in correspondence with the position of the epitaxially grown layer 3 at a predetermined thickness setting (step S9). The first reflective layer 8 is formed to have a curved mirror structure.

[0047] When this series of steps is completed, the surface light emitting device 1 according to the first embodiment is completed.

[0048] [Action and effect] As shown in FIG. 1, the surface-emitting device 1 according to the first embodiment includes a substrate 2, an epitaxially grown layer 3, a first electrode 6, a current injection region 5, a first reflective layer 8, and a second reflective layer 9. The substrate 2 has a first surface 2A and a second surface 2B opposite to the first surface 2A. The epitaxially grown layer 3 has a first semiconductor layer 31 of a first conductivity type, an active layer 32, and a second semiconductor layer 33 of a second conductivity type, which are sequentially stacked by epitaxial growth on the second surface 2B. A first electrode 6 is electrically connected to the first semiconductor layer 31. The current injection region 5 is formed on the surface of the second semiconductor layer 33 opposite to the substrate 2, is electrically connected to the second semiconductor layer 33, and is optically transparent. A first reflective layer 8 is formed on the first surface 2A. A second reflective layer 9 is formed on the surface of the current injection region 5 opposite to the second semiconductor layer 33. The epitaxial growth layer 3 has a distribution in thickness and cavity length. The first reflective layer 8 is formed on the first surface 2A at a position corresponding to a predetermined thickness of the epitaxial growth layer 3, and has a curved mirror structure. Therefore, the epitaxial growth layer 3 is formed to a thickness that minimizes the low threshold current density, and the light reflected by the first reflective layer 8 can be converged onto the epitaxial growth layer 3. Therefore, in the surface light emitting device 1, optical losses including diffraction losses can be effectively suppressed or prevented.

[0049] Furthermore, in the surface light emitting device 1, the layered structure of the epitaxially grown layer 3 is uniform within the second surface 2B, and therefore the above-mentioned effects can be obtained.

[0050] Furthermore, in the surface light emitting device 1, the epitaxially grown layer 3 is formed to a non-uniform thickness within the second surface 2B, thereby making it possible to obtain the above-mentioned effects.

[0051] Furthermore, in the surface light emitting device 1, the difference in optical film thickness of the epitaxially grown layer 3 corresponds to the spacing between two or more longitudinal modes with different oscillation wavelengths, and therefore the above-mentioned effects can be obtained.

[0052] Furthermore, in the surface light emitting device 1, the above-mentioned effects can be obtained by each of the multiple layers of the epitaxial growth layer 3 having a thickness distribution, or by each single layer of the epitaxial growth layer 3 having a thickness distribution.

[0053] Furthermore, in the surface light emitting device 1, the interface of the laminated structure of the epitaxial growth layer 3 is formed in a linear shape inclined with respect to the second surface 2B in side view, thereby making it possible to obtain the above-mentioned effects.

[0054] Furthermore, in the surface light emitting device 1, even if the epitaxial growth layer 3 is made of a material other than GaN, the above-mentioned effects can be obtained.

[0055] Furthermore, the light emitting device 10 includes an array of multiple surface light emitting elements 1. Therefore, the light emitting device 10 can effectively suppress or prevent optical losses including diffraction losses. Additionally, in the light emitting device 10, laser light having a plurality of wavelengths can be emitted from a plurality of surface light emitting elements 1, so speckle noise can be reduced.

[0056] Furthermore, the method for manufacturing the surface light emitting device 1 includes the following steps, as shown in FIGS. A first semiconductor layer 31 of a first conductivity type, an active layer 32, and a second semiconductor layer 33 of a second conductivity type are sequentially stacked on a second surface 2B opposite to the first surface 2A of the substrate 2 by an epitaxial growth layer 3, thereby forming an epitaxial growth layer 3 having a distribution in thickness and cavity length. A first electrode 6 is formed electrically connected to the first semiconductor layer 31. A current injection region 5 is formed on the surface of the second semiconductor layer 33 opposite to the substrate 2, the current injection region 5 being electrically connected to the second semiconductor layer 33 and having optical transparency. A second reflective layer 9 is formed on the surface of the current injection region 5 opposite to the second semiconductor layer 33 . The thickness of the epitaxially grown layer 3 is measured, and a first reflective layer 8 having a curved mirror structure is formed on the first surface 2A, corresponding to the position in the thickness of the epitaxially grown layer 3 where the threshold current density is minimum, for example. By carrying out these steps, it is possible to form a surface light emitting device 1 that can effectively suppress or prevent optical losses including diffraction losses.

[0057] 1, the surface-emitting device 1 can have the second reflective layer 9 tilted. This allows the surface-emitting device 1 to emit laser light in an oblique direction. In addition, by tilting the second reflective layer 9, the surface-emitting device 1 can have the reflectance dependent on the polarization direction, making it possible to control polarization.

[0058] <2. Second embodiment> A surface light emitting element 1 and a light emitting device 10 according to a second embodiment of the present disclosure will be described with reference to FIG. In the second embodiment and subsequent embodiments, components that are the same as or substantially the same as the components of the surface-emitting element 1 and light-emitting device 10 of the first embodiment are given the same symbols, and duplicate explanations are omitted.

[0059] FIG. 7 is a schematic diagram showing the longitudinal cross-sectional structure of the surface light emitting device 1 manufactured from the epitaxially grown layer 3 in the region indicated by the symbol B in FIG. In the surface light emitting device 1 according to the second embodiment, some of the interfaces of the layered structure of the epitaxial growth layer 3 are formed in a linear shape inclined with respect to the second surface 2B in side view. The other interfaces are formed in a linear shape without inclination with respect to the second surface 2B. In other words, in the surface light emitting device 1, the interface of the epitaxial growth layer 3 directly above the first reflective layer 8 does not need to have an inclination.

[0060] The other components are the same as those of the surface light emitting element 1 according to the first embodiment. The light emitting device 10 is constructed by arranging a plurality of surface light emitting elements 1 according to the second embodiment. Furthermore, the method for manufacturing the surface light emitting element 1 is substantially the same as that for manufacturing the surface light emitting element 1 according to the first embodiment.

[0061] According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the second embodiment, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the first embodiment.

[0062] 3. Third Embodiment A surface light emitting element 1 and a light emitting device 10 according to a third embodiment of the present disclosure will be described with reference to FIG.

[0063] FIG. 8 is a schematic diagram showing the longitudinal cross-sectional structure of the surface light emitting device 1 manufactured from the epitaxially grown layer 3 in the region indicated by the symbol C in FIG. In the surface light emitting device 1 according to the third embodiment, the interface of the layered structure of the epitaxial growth layer 3 is formed in a non-linear shape in a side view. To explain in more detail, the surface of the epitaxial growth layer 3 has jagged undulations. Furthermore, the width D of the flat portion on the surface of the epitaxial growth layer 3 is formed to be larger than the diameter R of the circular aperture (opening) in plan view. Here, the term "non-linear shape" is used to mean at least a shape formed by connecting a plurality of linear shapes having different inclinations and a curved shape.

[0064] The other components are the same as those of the surface light emitting element 1 according to the first embodiment. The light emitting device 10 is constructed by arranging a plurality of surface light emitting elements 1 according to the third embodiment. Furthermore, the method for manufacturing the surface light emitting element 1 is substantially the same as that for manufacturing the surface light emitting element 1 according to the first embodiment.

[0065] According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the third embodiment, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the first embodiment.

[0066] 4. Fourth Embodiment A surface light emitting element 1 and a light emitting device 10 according to a fourth embodiment of the present disclosure will be described with reference to Fig. 9. From the fourth embodiment onwards, a method for manufacturing the epitaxially grown layer 3 of the surface light emitting element 1 will be described.

[0067] 9A to 9C are schematic cross-sectional views illustrating steps in a method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1. FIG. In the method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1 according to the fourth embodiment, the temperature distribution of the substrate (wafer) 2 is changed during epitaxial growth to form a thickness distribution in the epitaxial growth layer 3. In general, the higher the temperature of the epitaxial growth layer 3, the faster the growth rate. Although not shown in the figure, the growth apparatus is configured such that, for example, the heater is positioned to the right side, providing a temperature distribution from left to right.

[0068] The other components are the same as those of the surface light emitting element 1 according to the first embodiment. The light emitting device 10 is constructed by arranging a plurality of surface light emitting elements 1 according to the fourth embodiment. Furthermore, the manufacturing method for the entire surface light emitting element 1 is substantially the same as that for the surface light emitting element 1 according to the first embodiment.

[0069] According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the fourth embodiment, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the first embodiment.

[0070] <5. Fifth Embodiment> A surface light emitting element 1 and a light emitting device 10 according to a fifth embodiment of the present disclosure will be described with reference to FIG.

[0071] 10A to 10C are schematic cross-sectional views illustrating steps in a method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1. FIG. In the method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1 according to the fifth embodiment, the concentration distribution of the deposition gas G on the substrate (wafer) 2 is changed during epitaxial growth to form a distribution in the thickness of the epitaxial growth layer 3. In the epitaxial growth layer 3, the growth rate increases as the concentration of the deposition gas G increases. Although not shown in the figure, the growth apparatus is configured such that the supply nozzle for the deposition gas G is positioned to the right, for example, to provide a gas concentration distribution from left to right.

[0072] The other components are the same as those of the surface light emitting element 1 according to the first embodiment. The light emitting device 10 is constructed by arranging a plurality of surface light emitting elements 1 according to the fifth embodiment. Furthermore, the manufacturing method for the entire surface light emitting element 1 is substantially the same as that for the surface light emitting element 1 according to the first embodiment.

[0073] According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the fifth embodiment, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the first embodiment.

[0074] 6. Sixth Embodiment A surface light emitting element 1 and a light emitting device 10 according to a sixth embodiment of the present disclosure will be described with reference to FIG.

[0075] 11A to 11C are schematic cross-sectional views illustrating steps in a method for manufacturing the epitaxially grown layer 3 of the surface light emitting device 1. FIG. In the method for manufacturing the epitaxially grown layer 3 of the surface light emitting device 1 according to the sixth embodiment, the substrate (wafer) 2 is rotated during epitaxial growth to form a thickness distribution in the epitaxially grown layer 3. For example, the right end of the substrate 2 is rotated around the center of rotation L C As the center of rotation L C When the substrate 2 is rotated around the center of the substrate 2, the rotation speed becomes faster at the left end of the substrate 2 than at the right end of the substrate 2. In other words, the temperature distribution (see FIG. 9) or the concentration distribution of the deposition gas G (see FIG. 10) becomes lower at the left end of the substrate 2 than at the right end, resulting in a slower growth rate. Although not shown, the growth apparatus is equipped with a mechanism for rotating the substrate 2.

[0076] The other components are the same as those of the surface light emitting element 1 according to the first embodiment. The light emitting device 10 is constructed by arranging a plurality of surface light emitting elements 1 according to the sixth embodiment. Furthermore, the manufacturing method for the entire surface light emitting element 1 is substantially the same as that for the surface light emitting element 1 according to the first embodiment.

[0077] According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the sixth embodiment, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the first embodiment.

[0078] 7. Seventh Embodiment A surface light emitting element 1 and a light emitting device 10 according to a seventh embodiment of the present disclosure will be described with reference to FIG.

[0079] 12A to 12C are schematic cross-sectional views illustrating steps in a method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1. FIG. In the method for manufacturing the epitaxially grown layer 3 of the surface light emitting device 1 according to the seventh embodiment, a substrate (wafer) 2 having a varied off-angle distribution is used during epitaxial growth, and a distribution is formed in the thickness of the epitaxially grown layer 3. In the epitaxially grown layer 3, the growth rate increases as the off-angle increases. Here, the substrate 2 having a varied off-angle distribution is used, but the methods for manufacturing the surface light emitting device 1 according to the fourth to sixth embodiments are also used, and the epitaxially grown layer 3 is formed by using a temperature distribution, a deposition gas concentration distribution, or rotation in combination.

[0080] The other components are the same as those of the surface light emitting element 1 according to the first embodiment. The light emitting device 10 is constructed by arranging a plurality of surface light emitting elements 1 according to the seventh embodiment. Furthermore, the manufacturing method for the entire surface light emitting element 1 is substantially the same as that for the surface light emitting element 1 according to the first embodiment.

[0081] According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the seventh embodiment, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the first embodiment.

[0082] 8. Eighth Embodiment The surface light emitting element 1 and the light emitting device 10 according to the eighth embodiment of the present disclosure will be described with reference to FIG. 13 and FIGS. 14A to 14F.

[0083] 13A and 13B show schematic cross sections illustrating steps in a method for manufacturing the epitaxially grown layer 3 of the surface light emitting device 1. FIG. 14A shows a planar configuration of the substrate 2 in the steps shown in FIG. In the method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1 according to the eighth embodiment, insulators 21 are formed at regular intervals on the second surface 2B of the substrate (wafer) 2. The insulators 21 are erected in the direction of arrow Z from the second surface 2B, spaced apart at regular intervals in the direction of arrow X, and formed in stripes extending in the direction of arrow Y.

[0084] The epitaxial growth layer 3 is formed on the substrate 2 with the insulators 21 formed on it. The epitaxial growth layer 3 is also formed on the side surfaces of the insulators 21, so that it is thicker along the side surfaces of the insulators 21 and thinner in the middle between the insulators 21. In other words, the thickness of the epitaxial growth layer 3 is distributed.

[0085] The other components are the same as those of the surface light emitting element 1 according to the first embodiment. The light emitting device 10 is constructed by arranging a plurality of surface light emitting elements 1 according to the eighth embodiment. Furthermore, the manufacturing method for the entire surface light emitting element 1 is substantially the same as that for the surface light emitting element 1 according to the first embodiment.

[0086] According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the eighth embodiment, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the first embodiment.

[0087] [First Modification] FIG. 14B shows a planar configuration of the substrate 2 according to the first modified example of the eighth embodiment, corresponding to FIG. 14A. In the method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1 according to the first modification, an insulator 21 is formed on the substrate 2 in a concentric ring shape in plan view, with the diameter increasing toward the periphery of the substrate 2. The epitaxial growth layer 3 has a thickness distribution formed by using the insulator 21. According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 relating to the first variant, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 relating to the eighth embodiment.

[0088] [Second Modification] FIG. 14C shows a planar configuration of the substrate 2 according to a second modified example of the eighth embodiment, corresponding to FIG. 14A. In the method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1 according to the second modification, insulators 21 formed in the shape of dots arranged at regular intervals in the directions of arrows X and Y in a plan view are formed on the substrate 2. In the epitaxial growth layer 3, the insulators 21 are used to form a distribution in thickness. According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 relating to the second variant, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 relating to the eighth embodiment.

[0089] [Third Modification] FIG. 14D shows a planar configuration of the substrate 2 according to the third modified example of the eighth embodiment, corresponding to FIG. 14A. In the method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1 according to the third modification, insulators 21 formed in a hexagonal shape (honeycomb shape) arranged at regular intervals in the directions of arrows X and Y in a plan view are formed on the substrate 2. In the epitaxial growth layer 3, a distribution in thickness is formed by using the insulators 21. According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 relating to the third variant, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 relating to the eighth embodiment.

[0090] [Fourth Modification] FIG. 14E shows a planar configuration of the substrate 2 according to the fourth modified example of the eighth embodiment, corresponding to FIG. 14A. In the method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1 according to the fourth modification, quadrangular (rectangular) insulators 21 are formed on the substrate 2 and are arranged at regular intervals in the directions of arrows X and Y in plan view. The epitaxial growth layer 3 has a thickness distribution formed by using the insulators 21. According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 relating to the fourth variant, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 relating to the eighth embodiment.

[0091] [Fifth Modification] FIG. 14F shows a planar configuration of the substrate 2 according to the fifth modified example of the eighth embodiment, corresponding to FIG. 14A. In the method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1 according to the fifth modification, insulators 21 formed in triangle shapes arranged at regular intervals in the directions of arrows X and Y in a plan view are formed on the substrate 2. In the epitaxial growth layer 3, the insulators 21 are used to form a thickness distribution. According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 relating to the fifth variant, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 relating to the eighth embodiment.

[0092] 9. Ninth Embodiment A surface light emitting element 1 and a light emitting device 10 according to a ninth embodiment of the present disclosure will be described with reference to FIG.

[0093] 15A to 15C are schematic cross-sectional views illustrating steps in a method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1. FIG. In the method for manufacturing the epitaxial growth layer 3 of the surface light emitting device 1 according to the ninth embodiment, grooves (cores) 22 arranged at regular intervals are formed on the second surface 2B of the substrate (wafer) 2. The grooves 22 are formed by digging from the second surface 2B in the direction opposite to the arrow Z direction. In plan view, the grooves 22 are formed in any of the shapes shown in FIGS. 14A to 14F, similar to the insulator 21 according to the eighth embodiment.

[0094] An epitaxial growth layer 3 is formed in a state in which grooves 22 are formed in the substrate 2. The presence of the grooves 22 slows down the deposition rate of the epitaxial growth layer 3 near the grooves 22, so the epitaxial growth layer 3 is thinner near the grooves 22 and thicker between the grooves 22. In other words, a distribution is formed in the thickness of the epitaxial growth layer 3.

[0095] The other components are the same as those of the surface light emitting element 1 according to the first embodiment. The light emitting device 10 is constructed by arranging a plurality of surface light emitting elements 1 according to the ninth embodiment. Furthermore, the manufacturing method for the entire surface light emitting element 1 is substantially the same as that for the surface light emitting element 1 according to the first embodiment.

[0096] According to the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the ninth embodiment, it is possible to obtain the same effects as those obtained by the surface-emitting element 1, light-emitting device 10, and method for manufacturing the surface-emitting element 1 of the eighth embodiment.

[0097] <10. Other embodiments> The present technology is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the technology. For example, in the present technology, two or more surface light emitting devices according to the above-described embodiments or modifications can be combined.

[0098] A surface light emitting device according to a first embodiment of the present disclosure includes a substrate, an epitaxially grown layer, a first electrode, a current injection region, a first reflective layer, and a second reflective layer. The substrate has a first surface and a second surface opposite to the first surface. The epitaxially grown layer has a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type, which are sequentially stacked by epitaxial growth on the second surface. The first electrode is electrically connected to the first semiconductor layer. The current injection region is formed on the surface of the second semiconductor layer opposite the substrate, is electrically connected to the second semiconductor layer, and is optically transparent. The first reflective layer is formed on the first surface. The second reflective layer is formed on the surface of the current injection region opposite the second semiconductor layer. The epitaxially grown layer has a distribution in thickness and cavity length, and the first reflective layer is formed on the first surface at a position corresponding to a predetermined thickness of the epitaxially grown layer, and has a curved mirror structure. Therefore, the epitaxial growth layer is formed to a thickness that minimizes the low threshold current density, and the light reflected by the first reflective layer can be focused onto the epitaxial growth layer, thereby effectively suppressing or preventing optical losses, including diffraction losses, in the surface-emitting device.

[0099] Furthermore, the light emitting device according to the second embodiment of the present disclosure includes a plurality of arranged surface light emitting elements, which makes it possible to effectively suppress or prevent optical losses, including diffraction losses, in the light emitting device.

[0100] Furthermore, a method for manufacturing a surface light emitting device according to a third embodiment of the present disclosure includes the following steps. A first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type are sequentially stacked on a second surface opposite to the first surface of the substrate by epitaxial growth layers, forming an epitaxial growth layer having a distribution in thickness and cavity length. A first electrode is formed electrically connected to the first semiconductor layer. A current injection region electrically connected to the second semiconductor layer and having optical transparency is formed on the surface of the second semiconductor layer opposite to the substrate. A second reflective layer is formed on the surface of the current injection region opposite to the second semiconductor layer. The thickness of the epitaxially grown layer is measured, and a first reflective layer having a curved mirror structure is formed at a predetermined position on the first surface. By carrying out these steps, it is possible to form a surface light emitting device that can effectively suppress or prevent optical losses including diffraction losses.

[0101] <Configuration of this technology> The present technology has the following configuration: According to the present technology having the following configuration, it is possible to provide a surface light emitting element, a light emitting device, and a method for manufacturing a surface light emitting element that can effectively suppress or prevent optical losses including diffraction losses. (1) a substrate having a first surface and a second surface opposite to the first surface; an epitaxially grown layer having a thickness and a cavity length distribution, the epitaxially grown layer including a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type, which are sequentially stacked on the second surface by epitaxial growth; an electrode electrically connected to the first semiconductor layer; a current injection region that is formed on a surface of the second semiconductor layer opposite to the substrate, is electrically connected to the second semiconductor layer, and has optical transparency; a first reflective layer having a curved mirror structure and formed on the first surface at a position corresponding to a predetermined thickness of the epitaxial growth layer; a second reflective layer formed on the surface of the current injection region opposite to the second semiconductor layer; A surface light emitting device comprising: (2) The layer structure of the epitaxially grown layer is the same within the second plane. The surface light emitting device according to (1) above. (3) The epitaxially grown layer has a distribution in thickness and cavity length within the second plane. The surface light emitting device according to (1) or (2) above. (4) The difference in optical thickness of the epitaxially grown layers is equal to or greater than the spacing between adjacent longitudinal modes. The surface light emitting device according to any one of (1) to (3) above. (5) Each of the plurality of epitaxially grown layers has a thickness distribution. The surface light emitting device according to any one of (1) to (4) above. (6) The single layer of the epitaxial growth layer has a distribution in thickness. The surface light emitting device according to any one of (1) to (4) above. (7) The interface of the laminated structure of the epitaxially grown layer is formed in a linear shape inclined relative to the second surface when viewed from the surface direction of the second surface. The surface light emitting device according to any one of (1) to (6) above. (8) A part of the interface of the laminated structure of the epitaxially grown layer is formed in a linear shape inclined with respect to the second surface when viewed from the surface direction of the second surface. The surface light emitting device according to any one of (1) to (6) above. (9) The interface of the laminated structure of the epitaxially grown layer is formed in a non-linear shape when viewed from the surface direction of the second surface. The surface light emitting device according to any one of (1) to (6) above. (10) The surface of the epitaxially grown layer has undulations when viewed from the surface direction of the second surface, The width of the flat portion of the surface of the epitaxial growth layer is greater than the diameter of the aperture. The surface light emitting device according to (9) above. (11) The epitaxial growth layer is formed of at least one material selected from the group consisting of GaN, InGaN, AlGaN, AlGaInN, GaAs, AlGaAs, AlAs, InGaAs, AlInGaP, InGaP, InP, InAlAs, AlInGaAs, AlGaAsP, InGaAs, InGaSb, and AlGaSb. The surface light emitting device according to any one of (1) to (10) above. (12) A plurality of surface light emitting elements are arranged, The surface light emitting device is a substrate having a first surface and a second surface opposite to the first surface; an epitaxially grown layer having a thickness and a cavity length distribution, the epitaxially grown layer including a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type, which are sequentially stacked on the second surface by epitaxial growth; an electrode electrically connected to the first semiconductor layer; a current injection region that is formed on a surface of the second semiconductor layer opposite to the substrate, is electrically connected to the second semiconductor layer, and has optical transparency; a first reflective layer having a curved mirror structure and formed on the first surface at a position corresponding to a predetermined thickness of the epitaxial growth layer; a second reflective layer formed on the surface of the current injection region opposite to the second semiconductor layer; A light emitting device comprising: (13) forming an epitaxially grown layer having a distribution in thickness and cavity length by sequentially stacking a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type on a second surface opposite to the first surface of the substrate; forming an electrode electrically connected to the first semiconductor layer; a current injection region electrically connected to the second semiconductor layer and having optical transparency is formed on a surface of the second semiconductor layer opposite to the substrate; forming a second reflective layer on a surface of the current injection region opposite to the second semiconductor layer; The thickness of the epitaxially grown layer is measured, and a first reflective layer having a curved mirror structure is formed at a predetermined position on the first surface. A method for manufacturing a surface light emitting device.

[0102] This application claims priority based on Japanese Patent Application No. 2021-145937, filed on September 8, 2021, with the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[0103] Those skilled in the art will recognize that various modifications, combinations, subcombinations, and variations may occur depending on design requirements and other factors, and are intended to be within the scope of the appended claims and their equivalents.

Claims

1. a substrate having a first surface and a second surface opposite to the first surface; an epitaxially grown layer having a thickness and a cavity length distribution, the epitaxially grown layer including a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type, which are sequentially stacked on the second surface by epitaxial growth; an electrode electrically connected to the first semiconductor layer; a current injection region that is formed on a surface of the second semiconductor layer opposite to the substrate, is electrically connected to the second semiconductor layer, and has optical transparency; a first reflective layer having a curved mirror structure, the first reflective layer being formed on the first surface at a position corresponding to a predetermined thickness of the epitaxial growth layer; a second reflective layer formed on the surface of the current injection region opposite to the second semiconductor layer; A surface light emitting device comprising:

2. The epitaxially grown layer has a distribution in thickness and a distribution in cavity length within the second plane. The surface light emitting device according to claim 1 .

3. The difference in optical thickness of the epitaxially grown layers is equal to or greater than the spacing between adjacent longitudinal modes. The surface light emitting device according to claim 1 .

4. The plurality of epitaxially grown layers each have a thickness distribution. The surface light emitting device according to claim 1 .

5. The single epitaxially grown layer has a thickness distribution. The surface light emitting device according to claim 1 .

6. The interface of the laminated structure of the epitaxially grown layers is formed in a linear shape inclined with respect to the second surface when viewed from the surface direction of the second surface. The surface light emitting device according to claim 1 .

7. A part of the interface of the laminated structure of the epitaxial growth layer is formed in a linear shape inclined with respect to the second surface when viewed from the surface direction of the second surface. The surface light emitting device according to claim 1 .

8. The interface of the laminated structure of the epitaxially grown layers is formed in a non-linear shape when viewed from the surface direction of the second surface. The surface light emitting device according to claim 1 .

9. the surface of the epitaxial growth layer has undulations when viewed from the plane direction of the second surface, The width of the flat portion of the surface of the epitaxial growth layer is greater than the diameter of the aperture. The surface light emitting device according to claim 8 .

10. The epitaxially grown layer is formed of at least one material selected from the group consisting of GaN, InGaN, AlGaN, AlGaInN, GaAs, AlGaAs, AlAs, InGaAs, AlInGaP, InGaP, InP, InAlAs, AlInGaAs, AlGaAsP, InGaAs, InGaSb, and AlGaSb. The surface light emitting device according to claim 1 .

11. A plurality of surface light emitting elements are arranged, The surface light emitting device is a substrate having a first surface and a second surface opposite to the first surface; an epitaxially grown layer having a thickness and a cavity length distribution, the epitaxially grown layer including a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type, which are sequentially stacked on the second surface by epitaxial growth; an electrode electrically connected to the first semiconductor layer; a current injection region that is formed on a surface of the second semiconductor layer opposite to the substrate, is electrically connected to the second semiconductor layer, and has optical transparency; a first reflective layer having a curved mirror structure, the first reflective layer being formed on the first surface at a position corresponding to a predetermined thickness of the epitaxial growth layer; a second reflective layer formed on the surface of the current injection region opposite to the second semiconductor layer; A light emitting device comprising:

12. a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type are sequentially stacked by epitaxial growth on a second surface of the substrate opposite to the first surface, thereby forming an epitaxially grown layer having a distribution in thickness and cavity length; forming an electrode electrically connected to the first semiconductor layer; a current injection region electrically connected to the second semiconductor layer and having optical transparency is formed on a surface of the second semiconductor layer opposite to the substrate; forming a second reflective layer on a surface of the current injection region opposite to the second semiconductor layer; a thickness of the epitaxially grown layer is measured, and a first reflective layer having a curved mirror structure is formed at a predetermined position on the first surface; A method for manufacturing a surface light emitting device.

Images