Light-emitting element, electronic apparatus, and method for manufacturing light-emitting element

Abstract

The present invention provides a light-emitting element capable of suppressing a decrease in light emission characteristics and / or a decrease in yield. A light-emitting element (10) according to the present art comprises: a substrate (101); a layered structure (LS) disposed on the substrate (101), the layered structure (LS) being obtained by layering a plurality of layers including a light-emitting layer (105); and a buffer layer (102) disposed between the substrate (101) and the layered structure (LS), the buffer layer (102) being composed of a material different from the material of the substrate (101). Through the light-emitting element according to the present art, it is possible to provide a light-emitting element capable of suppressing a decrease in light emission characteristics and / or a decrease in yield.

Description

Light-emitting element, electronic device, and method for manufacturing a light-emitting element

[0001] The technology disclosed herein (hereinafter also referred to as "this technology") relates to a light-emitting element, an electronic device, and a method for manufacturing a light-emitting element.

[0002] Conventionally, light-emitting elements such as surface-emitting lasers, edge-emitting lasers, and light-emitting diodes are known.

[0003] Some conventional light-emitting devices have a laminated structure on a substrate, in which multiple layers including a light-emitting layer are stacked (see, for example, Patent Document 1). This light-emitting device has a buffer layer between the substrate and the laminated structure.

[0004] Japanese Patent Application Publication No. 10-56201

[0005] However, conventional light-emitting elements could lead to a decrease in luminescence characteristics and / or a decrease in yield.

[0006] Therefore, the primary objective of this technology is to provide a light-emitting element that can suppress the deterioration of luminescence characteristics and / or the decrease in yield.

[0007] This technology provides a light-emitting element comprising: a substrate; a laminated structure disposed on the substrate, wherein a plurality of layers including a light-emitting layer are laminated; and a buffer layer disposed between the substrate and the laminated structure, wherein the buffer layer is made of a material different from the material of the substrate. The material of the buffer layer may have a higher thermal decomposition temperature than the material of the substrate. The substrate and the buffer layer may be made of the same material. At least the buffer layer of the substrate and the buffer layer may be made of a compound semiconductor containing Al. ｘ Ga １－ｘ The buffer layer is made of As (0 ≤ x ≤ 1), and the Al composition x of the buffer layer may be higher than that of the substrate. The substrate is made of GaAs, and the buffer layer may be made of AlGaAs. The carrier concentration of at least a portion of the buffer layer is 1 × 10⁻¹⁶ １７ cm －３ The above 3 x 10 １９ cm －３may be as described below. The buffer layer may have p-type conductivity. The p-type impurity contained in the buffer layer may be C. The total thickness of the buffer layer may be 50 nm or more. The buffer layer may have a plurality of stacked AlGaAs layers. At least two of the plurality of AlGaAs layers may have different Al compositions from each other. At least two of the plurality of AlGaAs layers may have different carrier concentrations from each other. At least one of the plurality of AlGaAs layers has a carrier concentration of 1×10 １７ cm －３ -3 or more and 3×10 １９ cm －３ -3 or less. The plurality of layers may include a reflective mirror on one side and / or the other side of the light-emitting layer. The reflective mirror may include a multilayer film reflective mirror. The present technology also provides an electronic device including a light-emitting element, which comprises: a substrate; a stacked structure disposed on the substrate, wherein the stacked structure is formed by stacking a plurality of layers including a light-emitting layer; and a buffer layer disposed between the substrate and the stacked structure, the buffer layer being made of a material different from that of the substrate. The present technology also provides a method for manufacturing a light-emitting element, which comprises: a step of growing a buffer material different from a substrate material that is the material of the substrate on the substrate to form a buffer layer; and a step of stacking a plurality of layers including a light-emitting layer on the buffer layer. The buffer material has a higher thermal decomposition temperature than the substrate material, and in the step of forming the buffer layer, the buffer material may be grown at a growth temperature higher than the thermal decomposition temperature of the substrate material. For the buffer material, CBr ４ or CBrCl ３ may be used as a doping material for doping C.

[0008] This is a cross-sectional view of a light-emitting element according to Example 1 of one embodiment of this technology. This is a plan view of a light-emitting element according to Example 1 of one embodiment of this technology. This is a flowchart for explaining an example of a method for manufacturing the light-emitting element of Figure 1. This is a cross-sectional view of each step of an example of a method for manufacturing the light-emitting element of Figure 1. This is a cross-sectional view of each step of an example of a method for manufacturing the light-emitting element of Figure 1. This is a cross-sectional view of each step of an example of a method for manufacturing the light-emitting element of Figure 1. This is a cross-sectional view of each step of an example of a method for manufacturing the light-emitting element of Figure 1. This is a cross-sectional view of each step of an example of a method for manufacturing the light-emitting element of Figure 1. This is a cross-sectional view of each step of an example of a method for manufacturing the light-emitting element of Figure 1. This is a cross-sectional view of a light-emitting element according to Example 2 of one embodiment of this technology. This is a cross-sectional view of a light-emitting element according to Example 3 of one embodiment of this technology. This is a cross-sectional view of a light-emitting element according to Example 4 of one embodiment of this technology. This is a cross-sectional view of a light-emitting element according to Example 5 of one embodiment of this technology. This is a cross-sectional view of a light-emitting element according to Example 6 of one embodiment of this technology. This is a flowchart for explaining an example of a method for manufacturing the light-emitting element of Figure 16. This is a cross-sectional view of each step of an example of a method for manufacturing the light-emitting element of Figure 16. This is a cross-sectional view of each step of an example of a method for manufacturing the light-emitting element of Figure 16. This is a cross-sectional view of each step of an example of a method for manufacturing the light-emitting element of Figure 16. This is a cross-sectional view of each step in an example of the manufacturing method of the light-emitting element shown in Figure 16. the light-emitting element according to Example 7 of one embodiment of the present technology. This is a plan view of the light-emitting element according to Example 7 of one embodiment of the present technology. This is a cross-sectional view of the light-emitting element according to Example 8 of one embodiment of the present technology. This is a cross-sectional view of the light-emitting element according to Example 9 of one embodiment of the present technology. This is a cross-sectional view of the light-emitting element according to Example 10 of one embodiment of the present technology. This is a cross-sectional view of the light-emitting element according to Example 11 of one embodiment of the present technology. This is a cross-sectional view of the light-emitting element according to Example 12 of one embodiment of the present technology. This is a plan view of the light-emitting element according to Example 12 of one embodiment of the present technology. This is a cross-sectional view of the light-emitting element according to Example 13 of one embodiment of the present technology.This is a cross-sectional view of a light-emitting element according to Embodiment 14 of one embodiment of this technology. This is a diagram showing an example of applying the light-emitting element according to this technology to a distance measuring device. This is a block diagram showing an example of the schematic configuration of a vehicle control system. This is an explanatory diagram showing an example of the installation position of a distance measuring device.

[0009] Preferred embodiments of the present technology will be described in detail below with reference to the attached drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations will be omitted. The embodiments described below represent typical embodiments of the present technology, and this will not be interpreted as narrowing the scope of the present technology. Even if this specification describes that a light-emitting element, electronic device, and method for manufacturing a light-emitting element according to the present technology have multiple effects, the light-emitting element, electronic device, and method for manufacturing a light-emitting element according to the present technology only need to have at least one effect. The effects described in this specification are merely examples and are not limiting, and other effects may also exist.

[0010] Furthermore, the explanation will proceed in the following order: 0. Introduction 1. Light-emitting element according to Example 1 of one embodiment of this technology 2. Light-emitting element according to Example 2 of one embodiment of this technology 3. Light-emitting element according to Example 3 of one embodiment of this technology 4. Light-emitting element according to Example 4 of one embodiment of this technology 5. Light-emitting element according to Example 5 of one embodiment of this technology 6. Light-emitting element according to Example 6 of one embodiment of this technology 7. Light-emitting element according to Example 7 of one embodiment of this technology 8. Light-emitting element according to Example 8 of one embodiment of this technology 9. Light-emitting element according to Example 9 of one embodiment of this technology 10. Light-emitting element according to Example 10 of one embodiment of this technology 11. Light-emitting element according to Example 11 of one embodiment of this technology 12. Light-emitting element according to Example 12 of one embodiment of this technology 13. Light-emitting element according to Example 13 of one embodiment of this technology 14. Light-emitting element according to Example 14 of one embodiment of this technology 15. Modifications of this technology 16. Examples of applications to electronic devices 17. Example of applying a surface-emitting laser to a distance measuring device 18. Example of mounting a distance measuring device on a mobile body

[0011] <0. Introduction> Among conventional light-emitting devices (e.g., surface-emitting lasers, edge-emitting lasers, light-emitting diodes, etc.), there are light-emitting devices that have a stacked structure in which multiple layers containing semiconductor layers are stacked on a substrate (see, for example, Patent Document 1). This light-emitting device has a buffer layer between the substrate and the stacked structure.

[0012] In conventional light-emitting devices, for example, a GaAs buffer layer is generally grown on the GaAs substrate to planarize the surface of the GaAs substrate before growing the epitaxial layer (semiconductor layer) on the GaAs substrate using the MOCVD method. The GaAs buffer layer is widely used because it is made of the same material as the GaAs substrate, but its material properties make it unsuitable for growth at very high temperatures. When the GaAs buffer layer is grown on the GaAs substrate at a suitable growth temperature (medium to low temperature), it is not possible to completely remove foreign matter such as oxide films, impurity elements, dust, and particles from the surface of the GaAs substrate, and this foreign matter may remain on the surface of the GaAs substrate. This remaining foreign matter increases crystal defects during epitaxial layer growth and reduces the flatness of the epitaxial layer. Therefore, there are concerns about a decrease in luminescence characteristics and / or yield.

[0013] Therefore, the inventors succeeded in developing a novel technology that suppresses the decrease in luminescence characteristics and / or yield by devising a relationship between the material of the buffer layer placed between the substrate and the laminated structure and the material of the substrate.

[0014] The inventors then developed a light-emitting element according to this technology as a light-emitting element that embodies this novel technology. According to this light-emitting element, it is possible to provide a light-emitting element that can suppress a decrease in luminescence characteristics and / or yield.

[0015] Furthermore, the inventors have developed a method for manufacturing light-emitting elements related to this technology as a method for realizing this novel technology. According to the method for manufacturing light-emitting elements related to this technology, it is possible to manufacture light-emitting elements that can suppress a decrease in luminescence characteristics and / or a decrease in yield.

[0016] Below, a light-emitting element according to one embodiment of this technology will be described in detail with reference to several examples. For convenience, in the following description, the upper part of the cross-sectional view such as Figure 1 will be referred to as "up" and the lower part as "down".

[0017] <1. Light-emitting element according to Example 1 of one embodiment of this technology>

[0018] The following describes the light-emitting element 10 according to Example 1 of one embodiment of this technology. <<Configuration of the light-emitting element>> (Overall configuration) Figure 1 is a cross-sectional view of the light-emitting element 10 according to Example 1 of one embodiment of this technology. Figure 2 is a plan view of the light-emitting element 10 according to Example 1 of one embodiment of this technology. Figure 1 is a cross-sectional view taken along line 1-1 in Figure 2.

[0019] The light-emitting element 10 is, for example, a vertical cavity surface-emitting laser (VCSEL). The light-emitting element 10 is, for example, a surface-emitting VCSEL. The oscillation wavelength λ of the light-emitting element 10 is, for example, 400 nm to 1550 nm (for example, 850 nm for GaAs-based elements, and over 900 nm for InGaAs-based elements). The light-emitting element 10 is driven by, for example, a driver (driving circuit). The driver is, for example, composed of a power supply and a transistor (for example, a MOSFET: Metal-Oxide-Semiconductor Field-Effect Transistor) that controls the on / off switching of power supplied from the power supply to the light-emitting element 10.

[0020] As an example, the light-emitting element 10 includes a substrate 101, a laminated structure LS disposed on the substrate 101 which has multiple layers (constituent layers) including a light-emitting layer 105 stacked on top of it, and a buffer layer 102 disposed between the substrate 101 and the laminated structure LS. Hereinafter, the direction in which the multiple layers are stacked in the laminated structure LS (up and down direction) will also be referred to as the "stacking direction".

[0021] In a laminated structure LS, for example, multiple layers (constituent layers) have reflectors on one side and the other side (bottom and top) of the light-emitting layer 105. Each reflector includes, for example, a multilayer reflector, such as a semiconductor multilayer reflector. The reflector on the bottom of the light-emitting layer 105 is also called the lower reflector. The reflector on the top of the light-emitting layer 105 is also called the upper reflector.

[0022] More specifically, the stacked structure LS, as an example, consists of multiple layers (constituent layers) stacked in this order from the substrate 101 side (bottom side): a first contact layer 103, a first semiconductor multilayer reflector 104 (lower DBR), an emissive layer 105, a second semiconductor multilayer reflector 107 (upper DBR) with an oxide constriction layer 106 arranged inside, and a second contact layer 108.

[0023] The laminated structure LS includes, for example, a mesa M containing a light-emitting layer 105. The mesa M is also called a "light-emitting mesa." The mesa M is, for example, circular in plan view (see Figure 2). That is, in this case, the mesa M is cylindrical. The diameter (average diameter) of the mesa M is, for example, several μm to several tens of μm (e.g., 10 μm to 30 μm). Note that the mesa M is not limited to being circular in plan view; for example, it may be elliptical in plan view, polygonal in plan view, etc.

[0024] Here, the mesa M is composed of a first semiconductor multilayer reflector 104, a light-emitting layer 105, a second semiconductor multilayer reflector 107 with an oxide constriction layer 106 arranged inside, and a second contact layer 108. That is, the mesa M is projected onto the first contact layer 103. The semiconductor layers included in the stacked structure LS are, as an example, made of III-V compound semiconductors (for example, GaAs-based compound semiconductors: compound semiconductors lattice-matched to GaAs). That is, the light-emitting element 10 can constitute, for example, a GaAs-based VCSEL.

[0025] As an example, at least the central part of the side and top surface of the mesa M is covered with an insulating film 112. The material of the insulating film 112 is SiO ２ Examples include SiN and SiON.

[0026] As an example, a circumferential (for example, ring-shaped) anode electrode 109 (p-side electrode) is provided on the upper surface of the mesa M (more specifically, the upper surface of the second contact layer 108) so as to surround the non-oxidized region 106a of the oxidized constriction layer 106 in a plan view. The inner diameter side of the anode electrode 109 becomes the discharge port.

[0027] As an example, a circumferential (e.g., ring-shaped) cathode electrode 111 (n-side electrode) is provided on the upper surface of the first contact layer 103 so as to surround the mesa M. An insulating film 112 is interposed between the cathode electrode 111 and the mesa M.

[0028] In the light-emitting element 10, the light-emitting layer 105 has a double heterostructure in which it is sandwiched in the stacking direction between first and second semiconductor multilayer reflectors 104 and 107 with different conductivity types, and holes and electrons can be recombined by light emission (radiative recombination) in the light-emitting layer 105.

[0029] Here, the resonator is constructed by including the light-emitting layer 105 and the first and second semiconductor multilayer reflectors 104 and 107. Alternatively, first and second cladding layers with different conductivity types may be provided between the first and second semiconductor multilayer reflectors 104 and 107, sandwiching the light-emitting layer 105 in the stacking direction. In this case, the resonator is constructed by including the light-emitting layer 105 and the first and second cladding layers.

[0030] The light-emitting element 10 emits laser light toward the upper surface of the mesa M (more specifically, the upper surface of the second contact layer 108).

[0031] (Substrate and buffer layer)

[0032] The substrate 101 may be, for example, a conductive substrate, a semi-insulating substrate, an insulating substrate, etc. The material of the substrate 101 may be a compound semiconductor, specifically a III-V compound semiconductor, such as Al ｘ Ga １－ｘ As (0 ≤ x ≤ 1).

[0033] The buffer layer 102 is preferably made of a material different from the material of the substrate 101.

[0034] Specifically, the material of the buffer layer 102 is a material with a higher thermal decomposition temperature than the material of the substrate 101, and is an Al-containing compound semiconductor (for example, a III-V compound semiconductor), for example, Al ｘ Ga １－ｘ It is preferable that As (0 ≤ x ≤ 1). In this case, it is preferable that the Al composition x of the buffer layer 102 is higher than that of the substrate 101.

[0035] The substrate 101 and the buffer layer 102 are preferably made of the same material, for example, a compound semiconductor of group III-V that is lattice-matched with each other.

[0036] Specifically, as the material for the substrate 101, Al ｘ１ Ga １－ｘ１ As (0 ≤ x 1 ≤ 1), for example, n-GaAs, p-GaAs, SI (Semi-Insulating)-GaAs, i-GaAs, etc. As the material for the buffer layer 102, p-Al ｘ２ Ga １－ｘ２ As (0<x2≦1, x1<x2), n-Al ｘ２ Ga １－ｘ２ Examples include As (0 < x² ≤ 1, x¹ < x²).

[0037] Here, the substrate 101 is made of, for example, GaAs, and the buffer layer 102 is made of, for example, AlGaAs. In particular, it is preferable that the buffer layer 102 has a p-type conductivity.

[0038] More specifically, the substrate 101 is made of, for example, n-GaAs, and the buffer layer 102 is made of, for example, p-AlGaAs.

[0039] Examples of n-type impurities (n-type dopants) contained in the substrate 101 include Si, Se, Te, Ge, and the like.

[0040] Examples of p-type impurities (p-type dopants) that may be contained in the buffer layer 102 include Zn, Mg, B, Be, C, etc., with C being particularly preferred.

[0041] If the buffer layer 102 contains C as a p-type impurity, the buffer material of the buffer layer 102 is AlGaAs, in addition to CBr, which is a doping material for doping with C. ４ or CBrCl ３ It is preferable to use Br, because Br exhibits a high etching and removal effect on foreign matter on the substrate 101 during the growth of the buffer material.

[0042] The carrier concentration (impurity concentration, dope concentration) of at least a portion of the buffer layer 102 is 1 × 10⁻⁶ １７ cm －３ The above 3 x 10１９ cm －３ The following is preferable:

[0043] The total thickness of the buffer layer 102 is preferably 50 nm or more, more preferably 200 nm or more, even more preferably 400 nm or more, and even more preferably 600 nm or more.

[0044] The buffer layer 102 has multiple stacked AlGaAs layers (for example, three AlGaAs layers 102A, 102B, and 102C). Here, of the three AlGaAs layers 102A, 102B, and 102C, AlGaAs layer 102A is closest to the substrate 101, and AlGaAs layer 102C is furthest from the substrate 101. Note that the buffer layer 102 is not limited to a three-layer structure, but may have a single-layer structure, a two-layer structure, or a stacked structure of four or more layers.

[0045] At least two of the multiple AlGaAs layers (for example, three AlGaAs layers 102A, 102B, and 102C) may have different Al compositions. Here, the three AlGaAs layers 102A, 102B, and 102C have p-type conductivity and different Al compositions. For example, AlGaAs layer 102A is p-Al ０．９ Ga ０．１ It consists of As, and the AlGaAs layer 102B is p-Al ０．６ Ga ０．４ It consists of As, and the AlGaAs layer 102C is p-Al ０．３ Ga ０．７ This is the As layer.

[0046] At least two of the multiple AlGaAs layers (for example, three AlGaAs layers 102A, 102B, and 102C) may have different film thicknesses. In this case, two of the three AlGaAs layers 102A, 102B, and 102C have different film thicknesses. For example, the film thickness of AlGaAs layer 102A is 200 nm, the film thickness of AlGaAs layer 102B is 200 nm, and the film thickness of AlGaAs layer 102C is 300 nm.

[0047] At least two of the multiple AlGaAs layers (for example, three AlGaAs layers 102A, 102B, and 102C) may have different carrier concentrations (impurity concentrations, doping concentrations). Here, the three AlGaAs layers 102A, 102B, and 102C have different carrier concentrations. At least one of the multiple AlGaAs layers (for example, three AlGaAs layers 102A, 102B, and 102C) has a carrier concentration of 1 × 10⁻⁶ １７ cm －３ The above 3 x 10 １９ cm －３ The following is preferable. For example, the carrier concentration of the AlGaAs layer 102A is 4 × 10 １８ cm －３ Therefore, the carrier concentration in the AlGaAs layer 102B is 2 × 10 １８ cm －３ Therefore, the carrier concentration in the AlGaAs layer 102C is 1 × 10⁻¹⁰ １８ cm －３ That is the case.

[0048] (First Contact Layer) The first contact layer 103 is disposed on the substrate 101 via the buffer layer 102 as described above. The first contact layer 103 contains, for example, a high concentration of n-type impurities (e.g., 1 × 10⁻⁶). １７ cm －３ The material consists of an n-GaAs layer doped with the above-mentioned impurities. Examples of n-type impurities include Si, Se, Te, and Ge. In this case, the n-type impurity is Si, and its doping concentration is 3 × 10⁻⁶. １８ cm －３ The thickness of the first contact layer 103 is, for example, 2 μm.

[0049] (First Semiconductor Multilayer Reflector) The first semiconductor multilayer reflector 104 is, for example, a semiconductor multilayer reflector doped with n-type impurities, which has low light absorption, high reflectivity and conductivity. A multilayer reflector is also called a distributed Bragg reflector (DBR). The first semiconductor multilayer reflector 104 has a structure in which high refractive index layers and low refractive index layers with different refractive indices are alternately stacked with an optical thickness of 1 / 4 wavelength of the emission wavelength of the light-emitting layer 105. The low refractive index layer is made of a compound semiconductor containing Al (e.g., AlGaAs, AlAs). The high refractive index layer is made of a compound semiconductor (e.g., AlGaAs, GaAs, etc.). The low refractive index layer is a high Al composition layer with a higher Al composition than the high refractive index layer. It is preferable that the refractive index difference (Al composition difference) between the high refractive index layer and the low refractive index layer be as large as possible. This is because a high reflectivity can be obtained with a small number of pairs. The Al composition of the low refractive index layer is preferably 0.8 or higher, and more preferably 0.85 or higher. The Al composition of the high refractive index layer is preferably 0.2 or lower, more preferably 0.15 or lower, even more preferably 0.1 or lower, and even more preferably 0.05 or lower. Examples of n-type impurities (n-type dopants) in the first semiconductor multilayer reflector 104 include Si, Se, Te, Ge, etc. Here, the reflectivity of the first semiconductor multilayer reflector 104 is set to be slightly higher than the reflectivity of the second semiconductor multilayer reflector 107.

[0050] (Light-emitting layer) The light-emitting layer 105 is, for example, made of a compound semiconductor having a bandgap energy smaller than that of the first and second semiconductor multilayer reflectors 104 and 107. The light-emitting layer 105 is, for example, made of a GaAs-based compound semiconductor (e.g., GaAs, AlGaAs, InGaAs, InGaAsN, etc.). The light-emitting layer 105 may have any of the following structures: quantum well structure, multiple quantum well structure, quantum nanowire structure, or quantum dot structure.

[0051] The emission wavelength of the light-emitting layer 105 is set to, for example, 400 nm to 1550 nm. The light-emitting layer 105 is designed according to the oscillation wavelength λ and application, but for example, when obtaining laser characteristics in the 900 nm band at an oscillation wavelength λ, the light-emitting layer 105 can be designed using a combination of an InGaAs-based active layer and an AlGaAs-based guide / barrier layer. It is preferable that the light-emitting layer 105 be positioned at or near the antinode of a standing wave generated in the resonator.

[0052] (Oxidation Constriction Layer) The oxidation constriction layer 106, as an example, has a non-oxidized region 106a and an oxidized region 106b surrounding the non-oxidized region 106a. The plan view outer shape of the non-oxidized region 106a is defined by the inner circumferential shape of the oxidized region 106b. The inner circumferential shape of the oxidized region 106b is defined by the outer circumferential shape of the mesa structure MS. The diameter (average diameter) of the non-oxidized region 106a is defined by the inner diameter (average inner diameter) of the oxidized region 106b. It is preferable that the oxidation constriction layer 106 be positioned at or near the node of the standing wave generated in the resonator. In the oxidation constriction layer, the non-oxidized region is also called OA (Oxide Aperture). In the oxidation constriction layer, the oxidation constriction diameter, which is the diameter of the non-oxidized region, is also called the "OA diameter".

[0053] The non-oxidizing region 106a functions as a current and light passing region. The non-oxidizing region 106a includes, as an example, a compound semiconductor containing Al (e.g., AlGaAs, AlAs, etc.). The Al composition of the non-oxidizing region 106a is preferably 0.8 or higher, more preferably 0.85 or higher, even more preferably 0.9 or higher, and even more preferably 0.95 or higher.

[0054] The oxidized region 106b is, for example, a circumferential (e.g., ring-shaped) region in plan view surrounding the non-oxidized region 106a. The oxidized region 106b is a region with higher resistance and lower refractive index than the non-oxidized region 106a, and functions as a current / light constriction region. The oxidized region 106b is, for example, an oxide containing Al (e.g., Al ｘ O ｙ Includes (etc.).

[0055] (Second Semiconductor Multilayer Reflector) The second semiconductor multilayer reflector 107 is, as an example, a semiconductor multilayer reflector doped with p-type impurities, which has low light absorption, high reflectivity and conductivity. A multilayer reflector is also called a distributed Bragg reflector (DBR). The second semiconductor multilayer reflector 107 has a structure in which high refractive index layers and low refractive index layers with different refractive indices are alternately stacked with an optical thickness of 1 / 4 wavelength of the emission wavelength of the light-emitting layer 105. The low refractive index layer is made of a compound semiconductor containing Al (e.g., AlGaAs, AlAs, etc.). The high refractive index layer is made of a compound semiconductor (e.g., AlGaAs, GaAs, etc.). The low refractive index layer is a high Al composition layer with a higher Al composition than the high refractive index layer. It is preferable that the refractive index difference (Al composition difference) between the high refractive index layer and the low refractive index layer is large, because high reflectivity can be obtained with a small number of pairs. The Al composition of the low refractive index layer is preferably 0.8 or higher, more preferably 0.85 or higher, even more preferably 0.9 or higher, and still more preferably 0.95 or higher. The Al composition of the high refractive index layer is preferably 0.2 or lower, more preferably 0.15 or lower, even more preferably 0.1 or lower, and still more preferably 0.05 or lower. Examples of p-type impurities (p-type dopants) in the second semiconductor multilayer reflector 107 include Zn, Mg, B, Be, C, etc. Here, the reflectance of the second semiconductor multilayer reflector 107 is set to be slightly lower than the reflectance of the first semiconductor multilayer reflector 104.

[0056] (Second Contact Layer) The second contact layer 108 may contain, for example, a high concentration of p-type impurities (e.g., 1 × 10⁻⁶). １７ cm －３ The p-type impurities consist of a p-GaAs layer doped with the above. Examples of such p-type impurities include Zn, Mg, B, Be, C, etc. The second contact layer 108 may be composed of a transparent conductive film made of, for example, ITO (Indium Tin Oxide) or IZO (Indium-Zinc-Oxide).

[0057] (Anode Electrode) The anode electrode 109 may have a single-layer structure or a multilayer structure. The anode electrode 109 is composed of at least one metal (including alloys) selected from the group consisting of, for example, Au, Ag, Pd, Pt, Ni, Ti, V, W, Cr, Al, Cu, Zn, Sn, Ge, and In. If the anode electrode 109 has a multilayer structure, it is composed of materials such as Ti / Au, Ti / Al, Ti / Al / Au, Ti / Pt / Au, Ni / Au, Ni / Au / Pt, Ni / Pt, Pd / Pt, Ag / Pd, etc. The anode electrode 109 is electrically connected to the anode side of the driver.

[0058] (Cathode Electrode) The cathode electrode 111 may have a single-layer structure or a multilayer structure. The cathode electrode 111 is composed of at least one metal (including alloys) selected from the group consisting of, for example, Au, Ag, Pd, Pt, Ni, Ti, V, W, Cr, Al, Cu, Zn, Sn, Ge, and In. If the cathode electrode 111 has a multilayer structure, it is composed of materials such as Ti / Au, Ti / Al, Ti / Al / Au, Ti / Pt / Au, Ni / Au, Ni / Au / Pt, Ni / Pt, Pd / Pt, Ag / Pd, AuGe / Ni / Au, etc. The cathode electrode 111 is electrically connected to the cathode side of the driver.

[0059] ≪Operation of the Surface-Emitting Laser≫ In the light-emitting element 10, the current flowing from the anode side of the driver to the anode electrode 109 passes through the second contact layer 108 and the second semiconductor multilayer reflector 107 in that order, is narrowed by the oxide narrowing layer 106, and injected into the light-emitting layer 105. At this time, the light-emitting layer 105 emits light, and the light travels back and forth between the first and second semiconductor multilayer reflectors 104 and 107, amplified by the light-emitting layer 105 and narrowed by the oxide narrowing layer 106, and when the oscillation conditions are met, it is emitted as laser light towards the top side of the mesa M. The current injected into the light-emitting layer 105 flows out to the cathode side of the driver via the first semiconductor multilayer reflector 104, and the first contact layer 103 and cathode electrode 111 in that order.

[0060] ≪An Example of a Method for Manufacturing a Light-Emitting Device≫ Below, an example of a method for manufacturing a light-emitting device 10 will be explained with reference to the flowchart in Figure 3. The overall process is as follows: First, multiple light-emitting devices 10 are simultaneously generated on a single wafer (hereinafter also referred to as "substrate 101" for convenience) which is the base material of the substrate 101, using a semiconductor manufacturing method with semiconductor manufacturing equipment. Next, the series of integrated light-emitting devices 10 are separated from each other by dicing (for example, stealth dicing) to obtain a chip-shaped light-emitting device 10.

[0061] In the first step S1, a buffer layer 102 is grown on the substrate 101 (see Figure 4). Specifically, three types of buffer materials (material for AlGaAs layer 102A, AlGaAs layer 102B, and AlGaAs layer 102C) different from the substrate material (e.g., n-GaAs) are sequentially grown on the substrate 101 using an epitaxial crystal growth method such as MOCVD (Metal Organic Chemical Vapor Deposition). Each buffer material consists of a material with a higher thermal decomposition temperature than the substrate material (e.g., n-GaAs) (e.g., p-AlGaAs) and a doping material (raw material) called CBr for doping with carbon. ４ or CBrCl ３ This includes the following: Here, the buffer material (e.g., p-AlGaAs) is grown at a growth temperature higher than the thermal decomposition temperature of the substrate material (e.g., n-GaAs).

[0062] Here, the AlGaAs layer has material properties that allow for crystal growth at higher temperatures than the GaAs layer. By growing a buffer material containing AlGaAs on the substrate 101 (GaAs substrate) at a temperature higher than the thermal decomposition temperature of GaAs, foreign matter such as oxide films, impurity elements, dust, and particles on the surface of the substrate 101 can be effectively removed, the occurrence of crystal defects during buffer layer growth is suppressed, and the flatness of the buffer layer 102 surface can be increased during high-temperature growth of the buffer material.

[0063] To add to that, CBr is used as a raw material for doping C. ４ or CBrCl ３By using this method, dust, particles, and other contaminants present on the substrate surface and inside the growth furnace can be more effectively etched away by the Br generated during thermal decomposition. This Br etching effect is more advantageous at higher growth temperatures, and by utilizing the Br etching effect during high-temperature growth of the buffer layer 102 (AlGaAs), it is possible to further enhance the cleaning effect on the substrate 101 (GaAs substrate) surface.

[0064] In the next step S2, a laminate L is generated by growing multiple layers (epitaxial layers) including the light-emitting layer 105 on the buffer layer 102 (see Figure 5). Specifically, a first contact layer 103, a first semiconductor multilayer mirror 104, a light-emitting layer 105, a second semiconductor multilayer mirror 107 with an oxide-to-oxidize layer 106S (e.g., an AlGaAs layer, an AlAs layer, etc.) inside which will be the material for the oxide-constricting layer 106, and a second contact layer 108 are grown in this order on the buffer layer 102 grown on the substrate 101 by an epitaxial crystal growth method such as MOCVD (Metal Organic Chemical Vapor Deposition), thereby generating a laminate L. When the laminate L is formed, the raw materials for the compound semiconductor include, for example, methyl-based organometallic gases such as trimethylaluminum (TMAl), trimethylgallium (TMGa), and trimethylindium (TMIn), and arsine (AshH ３ Using gas, the raw material for the donor impurity is, for example, disilane (Si ２ H ６ ) is used, and as the raw material for acceptor impurities, for example, carbon tetrabromide (CBr) ４ Use ).

[0065] In the next step S3, a mesa structure MS, which will become a mesa M, is formed (see Figure 6). Specifically, first, a resist pattern for forming the mesa structure MS is formed on the laminate by photolithography. Next, the laminate is etched using the resist pattern as a mask, for example, by dry etching. This etching is carried out until at least the first contact layer 103 is exposed. As a result, the mesa structure MS is formed. After that, the resist pattern is removed.

[0066] In the next step S4, an oxidized constriction layer 106 is formed (see Figure 7). Specifically, the mesa structure MS formed on the laminate (see Figure 6) is exposed to a high-temperature steam atmosphere to oxidize the oxidized layer 106S from the sides of the mesa structure MS toward the center by a thickness of several micrometers. As a result, the mesa structure MS becomes a mesa M.

[0067] In the next step S5, the anode electrode 109 is formed (see Figure 8). Specifically, for example, by lift-off, the anode electrode 109 is formed on the second contact layer 108 in a circumferential shape (for example, a ring shape) that surrounds the non-oxidizing region 106a in a plan view. At this time, for example, vapor deposition or sputtering is used to deposit the electrode material.

[0068] In the next step S6, the cathode electrode 111 is formed (see Figure 9). Specifically, the cathode electrode 111 is formed on the first contact layer 103 in a circumferential shape (e.g., a ring shape) surrounding the mesa M, for example, by the lift-off method. At this time, methods such as vapor deposition or sputtering are used to deposit the electrode material.

[0069] In the final step S7, the insulating film 112 is formed. Specifically, first, the insulating film 112 is deposited over the entire surface (see Figure 10). Next, the insulating film 112 on the anode electrode 109 and the insulating film 112 on the cathode electrode 111 are removed by photolithography and etching, exposing the anode electrode 109 and the cathode electrode 111 (see Figure 11). As a result, the insulating film 112 is formed on the side surface of the mesa M and on the inner diameter side of the anode electrode 109.

[0070] In the manufacturing method of the light-emitting element 10 described above, by growing a p-AlGaAs layer as a buffer layer 102 at a high temperature before growing the epitaxial layer on the substrate 101, it is possible to effectively remove foreign matter such as oxide films, impurity elements, dust, and particles present on the surface of the substrate 101 (GaAs substrate), and to improve the flatness of the buffer layer 102 surface and the epitaxial layer surface. As a result, the incorporation of foreign matter such as impurity elements, dust, and particles into the epitaxial layer is suppressed, and an epitaxial layer with high flatness can be grown. This makes it possible to stably manufacture light-emitting elements 10, including high-quality epitaxial wafers, with a good yield, in which the deterioration of light emission characteristics due to crystal defects is suppressed.

[0071] <<Effects of the light-emitting element and the method for manufacturing the light-emitting element>> The effects of the light-emitting element 10 will be explained below.

[0072] The light-emitting element 10 comprises a substrate 101, a laminated structure LS disposed on the substrate 101, the laminated structure LS having a plurality of layers including a light-emitting layer 105, and a buffer layer 102 disposed between the substrate 101 and the laminated structure LS, the buffer layer 102 being made of a material different from the material of the substrate 101.

[0073] In the light-emitting element 10, for example, the buffer layer 102 can be grown at a growth temperature higher than the growth temperature of the same material as the substrate 101, thereby improving the flatness of the buffer layer 102 surface while removing foreign matter from the substrate 101.

[0074] As a result, the light-emitting element 10 can be provided in which a decrease in light emission characteristics and / or a decrease in yield can be suppressed.

[0075] The material of the buffer layer 102 preferably has a higher thermal decomposition temperature than the material of the substrate 101. This allows the buffer layer 102 to be grown stably at a temperature higher than the growth temperature of the same material as the substrate 101, thereby improving the flatness of the buffer layer 102 surface while reliably removing foreign matter from the substrate 101.

[0076] The substrate 101 and the buffer layer are made of the same material. This allows, for example, the buffer layer 102 to be epitaxially grown on the substrate 101.

[0077] Of the substrate 101 and the buffer layer 102, at least the buffer layer 102 is made of a compound semiconductor containing Al. This makes it possible to raise the thermal decomposition temperature of at least the buffer layer 102.

[0078] Both the substrate 101 and the buffer layer 102 are made of Al ｘ Ga １－ｘ The buffer layer 102 is made of As (0 ≤ x ≤ 1), and it is preferable that the Al composition x of the buffer layer 102 is higher than that of the substrate 101. This makes it possible to make the thermal decomposition temperature of the buffer layer 102 higher than that of the substrate 101.

[0079] Preferably, the substrate 101 is made of GaAs and the buffer layer 102 is made of AlGaAs. This makes it possible to use GaAs for the substrate 101 while raising the thermal decomposition temperature of the buffer layer 102.

[0080] The carrier concentration in at least a portion of the buffer layer 102 is 1 × 10⁻⁶ １７ cm －３ The above 3 x 10 １９ cm －３ The following is preferable. This allows, for example, the growth conditions of the buffer layer 102 to be optimized.

[0081] The buffer layer 102 is preferably p-type conductive. Furthermore, the p-type impurity contained in the buffer layer 102 is preferably carbon (C). This allows for the doping material CBr, which is used to dope the buffer material, which is the material of the buffer layer 102, with carbon. ４ or CBrCl ３ You can use it.

[0082] The total thickness of the buffer layer 102 is preferably 50 nm or more. This allows for a sufficiently long growth time for the buffer layer 102, and enables more reliable removal of foreign matter on the substrate 101 during the growth of the buffer layer 102.

[0083] It is preferable that the buffer layer 102 has multiple stacked AlGaAs layers. This allows for control of the growth conditions in the thickness direction of the buffer layer 102.

[0084] Preferably, at least two of the multiple AlGaAs layers have different Al compositions. This allows for adjustment of the Al composition in the thickness direction of the buffer layer 102.

[0085] The multiple AlGaAs layers have different carrier concentrations. This allows for precise control of the growth conditions in the thickness direction of the buffer layer 102.

[0086] At least one of the multiple AlGaAs layers has a carrier concentration of 1 × 10⁻¹⁶ １７ cm －３ The above 3 x 10 １９ cm －３ The following is the result. This makes it possible to optimize the carrier concentration in the thickness direction of the buffer layer 102.

[0087] It is preferable that multiple layers have reflectors on one side and the other side of the light-emitting layer 105. This allows the light-emitting element 10 to constitute a VCSEL.

[0088] It is preferable that the reflector includes a multilayer reflector. This allows for high reflectivity.

[0089] A method for manufacturing a light-emitting element 10 includes the steps of forming a buffer layer 102 by growing a buffer material different from the substrate material on a substrate 101, and stacking a plurality of layers including a light-emitting layer 105 on the buffer layer 102.

[0090] In the manufacturing method of the light-emitting element 10, for example, the buffer layer 102 can be grown at a growth temperature higher than the growth temperature of the same material as the substrate 101, thereby removing foreign matter from the substrate 101.

[0091] As a result, the method for manufacturing the light-emitting element 10 makes it possible to manufacture a light-emitting element 10 that can suppress a decrease in light emission characteristics and / or a decrease in yield.

[0092] The buffer material has a higher thermal decomposition temperature than the substrate material, and in the process of forming the buffer layer 102, the buffer material is grown at a growth temperature higher than the thermal decomposition temperature of the substrate material. This makes it possible to remove foreign matter on the substrate 101 more reliably.

[0093] The buffer material is CBr, which is a doping material for doping C. ４ or CBrCl ３ This is used to enhance the etching and removal effect of foreign matter on the substrate 101.

[0094] <2. Light-emitting element according to Example 2 of one embodiment of this technology>

[0095] The following describes a light-emitting element 20 according to Example 2 of one embodiment of this technology. Figure 12 is a cross-sectional view of the light-emitting element 20 according to Example 2 of one embodiment of this technology.

[0096] As shown in Figure 12, the light-emitting element 20 has the same configuration as the light-emitting element 10 according to Example 1, except that the buffer layer 102 does not have an AlGaAs layer 102C.

[0097] The light-emitting element 20 can be manufactured by a manufacturing method that is generally the same as the manufacturing method for the light-emitting element 10 according to Example 1.

[0098] With the light-emitting element 20, the adjustability of the characteristics in the thickness direction of the buffer layer 102 is slightly inferior compared to the light-emitting element 10 according to Example 1, but the layer structure of the buffer layer 102 can be simplified.

[0099] <3. Light-emitting element according to Example 3 of one embodiment of this technology>

[0100] The following describes a light-emitting element 30 according to Example 3 of one embodiment of this technology. Figure 13 is a cross-sectional view of the light-emitting element 30 according to Example 3 of one embodiment of this technology.

[0101] As shown in Figure 13, the light-emitting element 30 has the same configuration as the light-emitting element 10 according to Example 1, except that the buffer layer 102 does not have AlGaAs layer 102B and AlGaAs layer 102C.

[0102] The light-emitting element 30 can be manufactured by a manufacturing method that is generally the same as the manufacturing method for the light-emitting element 10 according to Example 1.

[0103] With the light-emitting element 30, the adjustability of the characteristics in the thickness direction of the buffer layer 102 is inferior to that of the light-emitting element 10 according to Example 1, but the layer structure of the buffer layer 102 can be greatly simplified.

[0104] <4. Light-emitting element according to Example 4 of one embodiment of this technology>

[0105] The following describes a light-emitting element 40 according to Example 4 of one embodiment of this technology. Figure 14 is a cross-sectional view of the light-emitting element 40 according to Example 4 of one embodiment of this technology.

[0106] As shown in Figure 14, the light-emitting element 40 has the same configuration as the light-emitting element 10 according to Example 1, except that the positional relationship between the light-emitting layer 105 and the oxidation constriction layer 106 is different (reverse).

[0107] The light-emitting element 40 can be manufactured by a manufacturing method that is generally the same as the manufacturing method for the light-emitting element 10 according to Example 1.

[0108] The light-emitting element 40 provides generally the same effects as the light-emitting element 10 in Example 1.

[0109] <5. Light-emitting element according to Example 5 of one embodiment of this technology>

[0110] The following describes the light-emitting element 50 according to Example 5 of one embodiment of this technology. Figure 15 is a cross-sectional view of the light-emitting element 50 according to Example 5 of one embodiment of this technology.

[0111] As shown in Figure 15, the light-emitting element 50 has the same configuration as the light-emitting element 10 according to Embodiment 1, except that it is a back-side electrode type.

[0112] In the light-emitting element 50, the cathode electrode 111 is provided in a solid form on the back (bottom) surface of the substrate 101. Here, the substrate 101 is made of a conductive substrate, for example, an n-GaAs substrate.

[0113] In the light-emitting element 50, it is preferable that the carrier concentration of the buffer layer 102 located on the current path from the anode electrode 109 to the cathode electrode 111 is high (i.e., the conductivity of the buffer layer 102 is high).

[0114] The light-emitting element 50 can be manufactured by a manufacturing method that is generally the same as the manufacturing method for the light-emitting element 10 according to Example 1.

[0115] The light-emitting element 50 provides generally the same effects as the light-emitting element 10 according to Example 1.

[0116] <6. Light-emitting element according to Example 6 of one embodiment of this technology>

[0117] The following describes a light-emitting element 60 according to Example 6 of one embodiment of this technology. Figure 16 is a cross-sectional view of the light-emitting element 60 according to Example 6 of one embodiment of this technology.

[0118] The light-emitting element 60 has a configuration that is generally the same as the light-emitting element 10 according to Embodiment 1, except that, as shown in Figure 16, it is a back-emitting type VCSEL that emits light to the back side of the substrate 101.

[0119] In the light-emitting element 60, for example, the positional relationship between the upper and lower layers of the light-emitting layer 105 in the stacked structure LS is the opposite of that of the light-emitting element 10 in Example 1.

[0120] In the light-emitting element 60, an anode electrode 109 is provided on the upper surface of the second contact layer 108, which is located directly above the buffer layer 102, in the region surrounding the mesa M, so as to surround the mesa M.

[0121] In the light-emitting element 60, the lower reflector is configured including the second semiconductor multilayer reflector 107, and the upper reflector is configured including the first semiconductor multilayer reflector 104.

[0122] In the light-emitting element 60, a cathode electrode 111 is provided in a solid form on the first contact layer 103 which constitutes the top of the mesa M. The cathode electrode 111 can become a metallic reflector that, together with the first semiconductor multilayer reflector 104, constitutes a hybrid mirror (upper reflector). Here, the reflectivity of the upper reflector is set to be slightly higher than that of the lower reflector.

[0123] In the light-emitting element 60, as an example, an oxide constriction layer 106 is arranged within the second semiconductor multilayer reflecting mirror 107.

[0124] At least two of the multiple AlGaAs layers (for example, three AlGaAs layers 102A, 102B, and 102C) may have different Al compositions. Here, the three AlGaAs layers 102A, 102B, and 102C have p-type conductivity and different Al compositions. For example, AlGaAs layer 102A is p-Al ０．９ Ga ０．１ It consists of As, and the AlGaAs layer 102B is p-Al ０．５ Ga ０．５ It consists of As, and the AlGaAs layer 102C is p-Al ０．１ Ga ０．９ This is the As layer.

[0125] At least two of the multiple AlGaAs layers (for example, three AlGaAs layers 102A, 102B, and 102C) may have different film thicknesses. In this case, the three AlGaAs layers 102A, 102B, and 102C have different film thicknesses. For example, the film thickness of AlGaAs layer 102A is 300 nm, the film thickness of AlGaAs layer 102B is 200 nm, and the film thickness of AlGaAs layer 102C is 100 nm.

[0126] At least two of the multiple AlGaAs layers (for example, three AlGaAs layers 102A, 102B, and 102C) may have different carrier concentrations (impurity concentrations, doping concentrations). Here, the three AlGaAs layers 102A, 102B, and 102C have different carrier concentrations. At least one of the multiple AlGaAs layers (for example, three AlGaAs layers 102A, 102B, and 102C) has a carrier concentration of 1 × 10⁻⁶ １７ cm －３ The above 3 x 10 １９ cm －３ The following is preferable. For example, the carrier concentration of the AlGaAs layer 102A is 3 × 10 １８ cm －３ Therefore, the carrier concentration in the AlGaAs layer 102B is 1 × 10⁻⁶. １８ cm －３, and the carrier concentration of the AlGaAs layer 102C is 5×10 １７ cm －３ .

[0127] The second contact layer 108 has a film thickness of, for example, 1 μm, and a C doping concentration of, for example, 3×10 １９ cm －３ .

[0128] In the light-emitting element 60, as an example, the substrate 101 is formed of a semi-insulating substrate (e.g., an SI-GaAs substrate) or an insulating substrate (i-GaAs). By using a semi-insulating substrate or an insulating substrate with a low impurity concentration (including 0) as the substrate 101, light absorption in the substrate 101 is suppressed, and consequently, the light amount loss of emitted light can be reduced.

[0129] Hereinafter, an example of a method for manufacturing the light-emitting element 60 will be described with reference to the flowchart of FIG. 17 and the like. As an overall process, first, a plurality of light-emitting elements 60 are simultaneously formed on one wafer that is a base material of the substrate 101 (hereinafter also referred to as "substrate 101" for convenience) by a semiconductor manufacturing method using a semiconductor manufacturing apparatus. Next, the plurality of integrated light-emitting elements 60 are separated from each other by dicing (e.g., stealth dicing) to obtain chip-shaped light-emitting elements 60.

[0130] In the first step S11, a buffer layer 102 is grown on the substrate 101 (see FIG. 18). Specifically, three types of buffer materials (the material of the AlGaAs layer 102A, the material of the AlGaAs layer 102B, and the material of the AlGaAs layer 102C) different from the substrate material (e.g., n-GaAs) which is the material of the substrate 101 are sequentially grown on the substrate 101 by an epitaxial crystal growth method such as MOCVD (Metal Organic Chemical Vapor Deposition). For each buffer material, a material having a higher thermal decomposition temperature than the substrate material (e.g., n-GaAs) (e.g., p-AlGaAs), and CBr ４ or CBrCl ３ which is a doping material (raw material) for doping C is used. Here, the buffer material (e.g., p-AlGaAs) is grown at a growth temperature higher than the thermal decomposition temperature of the substrate material (e.g., n-GaAs).

[0131] Here, the AlGaAs layer allows crystal growth at a higher temperature than the GaAs layer as a material property. By growing a buffer material containing AlGaAs at a temperature higher than the thermal decomposition temperature of GaAs on the substrate 101 (GaAs substrate), foreign matters such as oxide films, impurity elements, dust, particles on the surface of the substrate 101 can be effectively removed, the generation of crystal defects during the growth of the buffer layer can be suppressed, and the flatness of the surface of the buffer layer 102 can be improved during the high-temperature growth of the buffer material.

[0132] It is additionally noted that CBr is used as a carbon-doping raw material ４ and CBrCl ３ is used, whereby dust, particles and the like existing on the substrate surface and in a growth furnace can be removed by an etching reaction through Br generated during thermal decomposition. Such an etching removal effect by Br is advantageous at a higher growth temperature, and the effect of cleaning the surface of the substrate 101 (GaAs substrate) can be further enhanced by using the etching removal effect of Br during the high-temperature growth of the buffer layer 102 (AlGaAs).

[0133] In the next step S12, a laminate is created by growing multiple layers (epitaxial layers) including the light-emitting layer 105 on the buffer layer 102 (see Figure 19). Specifically, a laminate is created by growing a second contact layer 108, a second semiconductor multilayer reflector 107 with an oxide-to-oxidize layer 106S (e.g., an AlGaAs layer, an AlAs layer, etc.) which will become the material for the oxide-constricting layer 106, an light-emitting layer 105, a first semiconductor multilayer reflector 104, and a first contact layer 103 in this order on the buffer layer 102 grown on the substrate 101 using an epitaxial crystal growth method such as MOCVD (Metal Organic Chemical Vapor Deposition). When forming the laminate, the raw materials for the compound semiconductor include, for example, methyl-based organometallic gases such as trimethylaluminum (TMAl), trimethylgallium (TMGa), and trimethylindium (TMIn), and arsine (AshH). ３ Using gas, the raw material for the donor impurity is, for example, disilane (Si ２ H ６ ) is used, and as the raw material for acceptor impurities, for example, carbon tetrabromide (CBr) ４ Use ).

[0134] In the next step S13, a mesa structure is formed (see Figure 20). Specifically, first, a resist pattern for forming the mesa structure is formed on the laminate by photolithography. Next, the laminate is etched using the resist pattern as a mask, for example, by dry etching. This etching is carried out until at least the second contact layer 108 is exposed. As a result, a mesa structure is formed. After that, the resist pattern is removed.

[0135] In the next step S14, an oxidized constricted layer 106 is formed (see Figure 21). Specifically, the mesa structure formed in the laminate (see Figure 20) is exposed to a high-temperature steam atmosphere to oxidize the oxidized layer 106S from the sides of the mesa structure toward the center by a thickness of several micrometers. As a result, the mesa structure becomes a mesa.

[0136] In the next step S15, the cathode electrode 111 is formed (see Figure 22). Specifically, the cathode electrode 111 is formed in a solid state on the first contact layer 103, for example by lift-off. At this time, methods such as vapor deposition and sputtering are used to deposit the electrode material.

[0137] In the next step S16, the anode electrode 109 is formed (see Figure 23). Specifically, the anode electrode 109 is formed in a circumferential shape (e.g., a ring shape) surrounding the mesa on the second contact layer 108, for example, by the lift-off method. At this time, methods such as vapor deposition or sputtering are used to deposit the electrode material.

[0138] In the final step S17, the insulating film 112 is formed. Specifically, first, the insulating film 112 is deposited over the entire surface (see Figure 24). Next, the insulating film 112 on the anode electrode 109 and the insulating film 112 on the cathode electrode 111 are removed by photolithography and etching, exposing the anode electrode 109 and the cathode electrode 111 (see Figure 25). As a result, the insulating film 112 is formed on the side surface of the mesa and on the inner diameter side of the anode electrode 109.

[0139] In the manufacturing method of the light-emitting element 60 described above, by growing a p-AlGaAs layer as a buffer layer 102 at a high temperature before growing the epitaxial layer on the substrate 101, it is possible to effectively remove foreign matter such as oxide films, impurity elements, dust, and particles present on the surface of the substrate 101 (GaAs substrate), and to improve the flatness of the buffer layer 102 surface and the epitaxial layer surface. As a result, the incorporation of foreign matter such as impurity elements, dust, and particles into the epitaxial layer is suppressed, and an epitaxial layer with high flatness can be grown. This makes it possible to stably manufacture light-emitting elements 10, including high-quality epitaxial wafers, with a good yield, in which the deterioration of light emission characteristics due to crystal defects is suppressed.

[0140] The light-emitting element 60 provides a back-side emission type VCSEL that has the same effects as the light-emitting element 10 according to Example 1.

[0141] <7. Light-emitting element according to Example 7 of one embodiment of this technology>

[0142] The following describes the light-emitting element 70 according to Example 7 of one embodiment of this technology. Figure 26 is a cross-sectional view of the light-emitting element 70 according to Example 7 of one embodiment of this technology. Figure 27 is a plan view of the light-emitting element 70 according to Example 7 of one embodiment of this technology. Figure 26 is a cross-sectional view taken along line 26-26 of Figure 27.

[0143] As shown in Figures 26 and 27, the light-emitting element 70 has a configuration that is generally the same as the light-emitting element 10 according to Example 1, except that it has a meshless structure.

[0144] The light-emitting element 70 has a multilayer structure LS with a plurality (for example, four) of trenches T (grooves) provided so as to surround the non-oxidized region 106a of the oxidation constriction layer 106 in a plan view. The bottom surface of the trench T is the upper surface of the first contact layer 103. An insulating film 112 is provided on the sides and around the opening end of the trench T. The cathode electrode 111 has a first electrode 111a provided on the bottom surface of the trench T and a second electrode 111b that extends in the depth direction of the trench T with its lower end in contact with the first electrode 111a within the trench T, where the insulating film 112 is provided on the side. The upper end of the second electrode 111b is located on the insulating film 112 around the opening end of the trench T.

[0145] The trench T also has the function of exposing the side surface of the oxide layer 106S during the oxidation process when manufacturing the light-emitting element 70.

[0146] The light-emitting element 70 can be manufactured by a manufacturing method that is generally the same as that for the light-emitting element 10 according to Example 1, except that a trench T is formed instead of a mesa M and an insulating film 112 and a cathode electrode 111 are formed in the trench T.

[0147] The light-emitting element 70 enables the realization of a surface-emitting VCSEL with a mesaless structure that provides the same effects as the light-emitting element 10 according to Example 1.

[0148] <8. Light-emitting element according to Example 8 of one embodiment of the present technology>

[0149] The following describes a light-emitting element 80 according to Example 8 of one embodiment of this technology. Figure 28 is a cross-sectional view of the light-emitting element 80 according to Example 8 of one embodiment of this technology.

[0150] As shown in Figure 28, the light-emitting element 80 has the same configuration as the light-emitting element 70 according to Example 7, except that instead of an insulating film 112 being provided in the trench T, a circumferential ion implantation region IIA is provided in the peripheral part of the trench T of the stacked structure LS in a plan view.

[0151] Examples of ion species in ion implantation region IIA include B+, H+, and the like.

[0152] The light-emitting element 80 can be manufactured by a manufacturing method that is generally the same as that for the light-emitting element 10 according to Example 1, except that an ion implantation region IIA is formed in the trench T instead of forming an insulating film 112.

[0153] The light-emitting element 80 enables the realization of a surface-emitting VCSEL with a mesaless structure that provides the same effects as the light-emitting element 10 according to Example 1.

[0154] <9. Light-emitting element according to Example 9 of one embodiment of this technology>

[0155] The following describes the light-emitting element 90 according to Example 9 of one embodiment of this technology. Figure 29 is a cross-sectional view of the light-emitting element 90 according to Example 9 of one embodiment of this technology.

[0156] As shown in Figure 29, the light-emitting element 90 has the same configuration as the light-emitting element 10 according to Embodiment 1, except that it constitutes a surface-emitting type surface-emitting laser array.

[0157] In the light-emitting element 90, a stacked structure LS of multiple surface-emitting lasers (excluding the first contact layer 103) is arranged in an array on the substrate 101 via a buffer layer 102. That is, in the light-emitting element 90, multiple surface-emitting lasers (VCSELs) share the substrate 101, the buffer layer 102, and the first contact layer 103.

[0158] The light-emitting element 90 has an electrode layout in which the anode is independent and the cathode is common, and each surface-emitting laser can be driven independently.

[0159] The light-emitting element 90 can be manufactured by a manufacturing method that is generally the same as that used for the light-emitting element 10 according to Example 1, except that multiple surface-emitting lasers are formed in an array.

[0160] The light-emitting element 90 enables the realization of a surface-emitting type surface-emitting laser array in which the same effects as the light-emitting element 10 in Example 1 are obtained for each surface-emitting laser.

[0161] <10. Light-emitting element according to Example 10 of one embodiment of the present technology>

[0162] The following describes a light-emitting element 100 according to Example 10 of one embodiment of this technology. Figure 30 is a cross-sectional view of the light-emitting element 100 according to Example 10 of one embodiment of this technology.

[0163] As shown in Figure 30, the light-emitting element 100 has the same configuration as the light-emitting element 10 according to Example 1, except that it constitutes a surface-emitting type InP-based VCSEL.

[0164] In the light-emitting element 100, the substrate 101, buffer layer 102, first contact layer 103, first semiconductor multilayer reflector 104, light-emitting layer 105, BTJ (buried tunnel junction), and dielectric multilayer reflector 118 are stacked in this order.

[0165] (Substrate) The substrate 101 is, for example, a semi-insulating substrate or an insulating substrate, such as an SI (Semi-Insulating)-InP substrate, an i-InP substrate, etc. The substrate 101 may also be a conductive substrate, such as an n-InP substrate, a p-InP substrate, etc.

[0166] (Buffer layer) The buffer layer 102 has three InP-based compound semiconductor layers 102D, 102E, and 102F. The three InP-based compound semiconductor layers 102D, 102E, and 102F are stacked in this order from the substrate 101 side. Note that the buffer layer 102 is not limited to a three-layer structure, but may have a single-layer structure, a two-layer structure, or a stacked structure of four or more layers.

[0167] Each InP-based compound semiconductor layer in the buffer layer 102 is, for example, an InP-based compound semiconductor layer containing Al, such as AlInAs or AlGaInAs. Each InP-based compound semiconductor layer in the buffer layer 102 preferably has a p-type conductivity, and in this case, the p-type impurity is preferably C. ４ or CBrCl ３ This is because it can be used as a doping material. At least two of the three InP-based compound semiconductor layers 102D, 102E, and 102F of the buffer layer 102 may differ in at least one of their Al composition, film thickness, and carrier concentration.

[0168] (First Contact Layer) The first contact layer 103 consists of, for example, a highly doped n-InP layer. For example, Si can be used as the dopant for the n-InP layer.

[0169] (First semiconductor multilayer reflecting mirror) The first semiconductor multilayer reflecting mirror 104 is, as an example, made of a compound semiconductor (InP-based compound semiconductor) that is lattice-matched to InP. The first semiconductor multilayer reflecting mirror 104 is made of, for example, n-InP / n-AlGaInAs or n-AlInAs / n-AlGaInAs.

[0170] (Emitting Layer) The emissive layer 105 is made of an InP-based compound semiconductor, for example. More specifically, the emissive layer 105 has a multiple quantum well structure (MQW structure) made of AlGaInAs or GaInAsP, for example. Here, the emissive layer 105 is made of, for example, an AlGaInAs / AlGaInAs multiple quantum well layer. The composition and film thickness of the AlGaInAs / AlGaInAs multiple quantum well layer are designed so that the emission wavelength is, for example, 1450 nm (eye-safe band), but it is preferable to introduce opposing strains into the well layer and the barrier layer. In this case, for example, the magnitude of the strain can be about 0.5%, and the number of wells can be 6. The emissive region of the emissive layer 105 corresponds to the tunnel junction layer 116, which will be described later.

[0171] (BTJ) The BTJ includes a tunnel junction layer 116 and a burial layer 117. As described above, the BTJ is located on the opposite side (upper side) of the light-emitting layer 105 from the substrate 101 side. That is, the BTJ is located upstream of the current path from the anode electrode 109 to the cathode electrode 111 with respect to the light-emitting layer 105.

[0172] The embedded layer 117 is made of, for example, an n-InP layer. For example, Si can be used as the dopant for the n-InP layer.

[0173] The tunnel junction layer 116 is provided in a mesa-like manner on the light-emitting layer 105. Therefore, in the following, the tunnel junction layer 116 will also be referred to as the "TJ mesa". The region of the embedding layer 117 surrounding the TJ mesa has a higher resistance than the TJ mesa, thus becoming a current-constricted region. The region of the embedding layer 117 surrounding the TJ mesa has a lower refractive index than the TJ mesa, thus becoming an optical-constricted region. The diameter of the TJ mesa is, for example, several tens of micrometers.

[0174] The tunnel junction layer 116 includes a p-type semiconductor region 116a and an n-type semiconductor region 116b stacked on top of each other. Here, the p-type semiconductor region 116a is located on the light-emitting layer 105 side (lower side) of the n-type semiconductor region 116b. The p-type semiconductor region 116a is made of p-AlInAs, for example, which is highly doped with carbon (C). The n-type semiconductor region 116b is made of n-InP, for example, which is highly doped with Si, Te, etc. Note that one of the p-type semiconductor region 116a and the n-type semiconductor region 116b may be made of AlInAs and the other of InP, or both may be made of AlInAs or InP.

[0175] (Dielectric Multilayer Reflector) The dielectric multilayer reflector 118 has low light absorption, high reflectivity, and insulating properties. Multilayer reflectors are also called distributed Bragg reflectors (DBRs). The dielectric multilayer reflector 118 has a structure in which high refractive index layers and low refractive index layers with different refractive indices are alternately stacked with an optical thickness of 1 / 4 wavelength of the emission wavelength of the light-emitting layer 105. The dielectric multilayer reflector 118 is made of, for example, SiO ２ , TiO２ Ta ２ O ５ , SiN, a-Si, MgF ２ and CaF ２ Preferably, the material comprises at least one of the following. For example, the dielectric multilayer reflector 118 may be made of, for example, SiO ２ / TiO ２ Ta ２ O ５ / SiO ２ a-Si / Ta ２ O ５ It may also be composed of these.

[0176] The light-emitting element 100 makes it possible to realize a surface-emitting InP-based VCSEL that has the same effects as the light-emitting element 10 according to Example 1.

[0177] <11. Light-emitting element according to Example 11 of one embodiment of the present technology>

[0178] The following describes a light-emitting element 110 according to Example 11 of one embodiment of this technology. Figure 31 is a cross-sectional view of the light-emitting element 110 according to Example 11 of one embodiment of this technology.

[0179] As shown in Figure 31, the light-emitting element 110 has a configuration that is generally the same as the light-emitting element 10 according to Embodiment 1, except that it is a surface-emitting type light-emitting diode (LED).

[0180] The light-emitting element 110 does not have a second semiconductor multilayer reflector 107.

[0181] In the light-emitting element 110, the combined light of the light emitted downward from the light-emitting layer 105 and reflected by the first semiconductor multilayer mirror 104, and the light emitted upward from the light-emitting layer 105, is emitted towards the top of the mesa M.

[0182] The light-emitting element 110 can be manufactured by a manufacturing method that is generally the same as that used for the light-emitting element 10 in Example 1, except that the second semiconductor multilayer reflector 107 is not formed.

[0183] The light-emitting element 110 enables the realization of a surface-emitting LED that provides the same effects as the light-emitting element 10 according to Example 1.

[0184] <12. Light-emitting element according to Example 12 of one embodiment of the present technology>

[0185] The following describes the light-emitting element 120 according to Example 12 of one embodiment of this technology. Figure 32 is a cross-sectional view of the light-emitting element 120 according to Example 12 of one embodiment of this technology. Figure 33 is a plan view of the light-emitting element 120 according to Example 12 of one embodiment of this technology. Figure 32 is a cross-sectional view taken along line 32-32 in Figure 33.

[0186] As shown in Figures 32 and 33, the light-emitting element 120 has a configuration that is generally the same as the light-emitting element 10 according to Embodiment 1, except that it is an end-face emission type semiconductor laser (end-face emission laser).

[0187] In the light-emitting element 120, the stacked structure LS is rectangular in plan view, and a first contact layer 103, a first cladding layer 119A (n-type compound semiconductor layer), an emissive layer 105 (compound semiconductor layer), a second cladding layer 119B (p-type compound semiconductor layer), and a second contact layer 108 are stacked in this order. The first cladding layer 119A, the emissive layer 105, and the second cladding layer 119B constitute a double heterostructure. An anode electrode 109 (for example, a stripe electrode) is provided on the second contact layer 108. A pair of cathode electrodes 111, 111 are provided on the upper surface of the first contact layer 103 via an insulating film 112, sandwiching the mesa of the stacked structure LS. The refractive indices of the first and second cladding layers 119A and 119B are lower than the refractive index of the emissive layer 105, thereby achieving a light confinement effect in the emissive layer 105. The band gaps of the first and second cladding layers 119A and 119B are larger than the band gap of the light-emitting layer 105, thus achieving a carrier confinement effect in the light-emitting layer 105.

[0188] The light-emitting element 120 has a double heterostructure, and one end face and the other end face are cleavage planes, resulting in a highly reflective reflective surface (also called a "resonator end face"). The reflectivity of this pair of reflective surfaces, the first and second reflective surfaces R1 and R2 (see Figure 33), is set to different values, as an example.

[0189] In the light-emitting element 120, the current supplied from the anode side of the driver is injected into the light-emitting layer 105 from the anode electrode 109 through the second contact layer 108 and the second cladding layer 119B in that order. At this time, the light-emitting layer 105 emits light, and the light is confined within the light-emitting layer 105 while reciprocating between the first and second reflective surfaces R1 and R2. When the oscillation conditions are met, the light is emitted as laser light from the first and second reflective surfaces R1 and R2, respectively.

[0190] The light-emitting element 120 can be manufactured by a manufacturing method that is generally the same as that for the light-emitting element 10 according to Example 1, except that a pair of resonator end faces are formed instead of forming the first and second semiconductor multilayer reflectors 104 and 107.

[0191] The light-emitting element 120 makes it possible to realize an end-face emitting laser that has the same effects as the light-emitting element 10 according to Example 1.

[0192] <13. Light-emitting element according to Example 13 of one embodiment of the present technology>

[0193] The following describes a light-emitting element 130 according to Example 13 of one embodiment of this technology. Figure 34 is a cross-sectional view of the light-emitting element 130 according to Example 13 of one embodiment of this technology.

[0194] As shown in Figure 34, the light-emitting element 130 has the same configuration as the light-emitting element 120 according to Example 12, except that the stacked structure LS is provided with an ion implantation region IIA as a current constriction region.

[0195] In the light-emitting element 130, ion implantation regions IIA (current constriction regions) are provided on both sides of the region corresponding to the anode electrode 109 (striped electrode) of the stacked structure LS. This makes it possible to increase the current density of the current injected into the light-emitting layer 105.

[0196] The light-emitting element 130 can be manufactured by a manufacturing method that is generally the same as that for the light-emitting element 120 according to Example 12, except that it forms an ion implantation region IIA.

[0197] The light-emitting element 130 enables the realization of a highly efficient end-face emitting laser that provides the same effects as the light-emitting element 10 in Example 1.

[0198] <14. Light-emitting element according to Example 14 of one embodiment of this technology>

[0199] The following describes a light-emitting element 140 according to one embodiment of this technology. Figure 35 is a cross-sectional view of the light-emitting element 140 according to one embodiment of this technology.

[0200] The light-emitting element 140 has a configuration that is generally the same as the light-emitting element 60 according to Example 6, except that the upper reflector has a dielectric multilayer reflector 118 and an anode electrode 109 in addition to the second semiconductor multilayer reflector 107.

[0201] The dielectric multilayer reflector 118 has low light absorption, high reflectivity, and insulating properties. Multilayer reflectors are also called distributed Bragg reflectors (DBRs). The dielectric multilayer reflector 118 has a structure in which high refractive index layers and low refractive index layers with different refractive indices are alternately stacked with an optical thickness of 1 / 4 wavelength of the emission wavelength of the light-emitting layer 105. The dielectric multilayer reflector 118 is made of, for example, SiO ２ , TiO ２ Ta ２ O ５ , SiN, a-Si, MgF ２ and CaF ２ Preferably, the material comprises at least one of the following. For example, the dielectric multilayer reflector 118 may be made of, for example, SiO ２ / TiO ２ Ta ２ O ５ / SiO ２ a-Si / Ta ２ O ５ It may also be composed of these.

[0202] The anode electrode 109 is provided to cover the dielectric multilayer reflector 118 from above and the side and to be in contact with the second contact layer 108. The anode electrode 109 is made of a metal plating such as Au, Ag, or Al.

[0203] The light-emitting element 140 can be manufactured by a manufacturing method that is generally the same as that for the light-emitting element 60 according to Example 6, except that the dielectric multilayer reflector 118 and the anode electrode 109 are formed as described above.

[0204] The light-emitting element 140 makes it possible to provide a high-power back-side emission type VCSEL.

[0205] In addition, in the light-emitting element 140, the anode electrode 109 may be provided so as to cover only the side surface of the dielectric multilayer reflector 118 and to be in contact with the second contact layer 108. In this case, the anode electrode 109 does not constitute part of the upper reflector.

[0206] <15. Modifications of the Technology> The technology is not limited to the above embodiments and can be modified in various ways.

[0207] For example, if the substrate 101 is Al ｘ１ Ga １－Ｘ１ It consists of As (0 < X1 ≤ 1), and the buffer layer 102 is Al ｘ２ Ga １－Ｘ２ As may also be (0 < X2 ≤ 1, X1 < X2).

[0208] For example, the light-emitting element according to this technology may be a GaN-based light-emitting element (e.g., a surface-emitting laser, an edge-emitting laser, a light-emitting diode, etc.) in which a stacked structure LS including a GaN-based compound semiconductor layer (a compound semiconductor lattice-matched to GaN) is arranged on a substrate 101 (e.g., a sapphire substrate, a GaN substrate, etc.) via a buffer layer 102. In this case as well, it is desirable that the thermal decomposition temperature of the buffer layer 102 is higher than the thermal decomposition temperature of the substrate 101.

[0209] The light-emitting element in this technology can use any material that emits light at any wavelength within the wavelength range of 200 to 2500 nm.

[0210] In the light-emitting elements according to each of the above embodiments and modifications, the conductivity types (p-type and n-type) of the semiconductor layer located above the light-emitting layer 105 and the semiconductor layer located below the light-emitting layer 105 may be reversed. However, in this case, the relative positions of the anode electrode and the cathode electrode must also be reversed.

[0211] Some of the configurations of the light-emitting elements in each of the above embodiments and their respective modifications may be combined within a range that is not contradictory to one another.

[0212] In each of the above embodiments and modifications, the arrangement, material, conductivity type, thickness, width, numerical values, shape, size, etc., of each layer constituting the light-emitting element can be appropriately changed within the range that allows it to function as a light-emitting element.

[0213] <16. Examples of Application to Electronic Devices> The technology relating to this disclosure (this technology) can be applied to various products (electronic devices). For example, the technology relating to this disclosure may be implemented as a device mounted on any type of mobile device such as automobiles, electric vehicles, hybrid electric vehicles, motorcycles, bicycles, personal mobility devices, airplanes, drones, ships, robots, etc., or on low-power devices (e.g., smartphones, smartwatches, tablets, mice, laptops, etc.) or wired or wireless communication devices.

[0214] The light-emitting element related to this technology can be applied, for example, as a light source for devices that form or display images using light (e.g., printers, copiers, projectors, head-mounted displays, head-up displays, etc.).

[0215] <17. Example of applying a light-emitting element to a distance measuring device> Below, an example of the application of the light-emitting element 10 according to Embodiment 1 of one embodiment of this technology will be described.

[0216] Figure 36 shows an example of the schematic configuration of a distance measuring device 1000 (distance measuring device) equipped with a light-emitting element 10, as an example of an electronic device related to this technology. The distance measuring device 1000 measures the distance to a subject S using the TOF (Time Of Flight) method. The distance measuring device 1000 is equipped with a light-emitting element 10. The distance measuring device 1000 includes, for example, a light-emitting element 10, a light-receiving device 125, lenses 128 and 138, a signal processing unit 145, a control unit 155, a display unit 165, and a storage unit 175.

[0217] The light receiving device 125 receives light emitted from the light-emitting element 10 and reflected by the object S. In other words, the light receiving device 125 detects the light reflected by the object S. The lens 128 is a lens for aligning the light emitted from the light-emitting element 10, and is, for example, a collimating lens. The lens 138 is a lens for focusing the light reflected by the object S and guiding it to the light receiving device 125, and is, for example, a focusing lens.

[0218] The signal processing unit 145 is a circuit for generating a signal corresponding to the difference between the signal input from the light receiving device 125 and the reference signal input from the control unit 155. The control unit 155 is configured to include, for example, a Time to Digital Converter (TDC). The reference signal may be a signal input from the control unit 155, or it may be an output signal from a detection unit that directly detects the output of the light-emitting element 10. The control unit 155 is a processor that controls, for example, the light-emitting element 10, the light receiving device 125, the signal processing unit 145, the display unit 165, and the storage unit 175. The control unit 155 is a circuit for measuring the distance to the subject S based on the signal generated by the signal processing unit 145. The control unit 155 generates a video signal for displaying information about the distance to the subject S and outputs it to the display unit 165. The display unit 165 displays information about the distance to the subject S based on the video signal input from the control unit 155. The control unit 155 stores the information about the distance to the subject S in the storage unit 175.

[0219] In this application example, instead of the light-emitting element 10, any of the light-emitting elements 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, or 140 can be applied to the distance measuring device 1000.

[0220] <18. Example of mounting a distance measuring device on a mobile body> Figure 37 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile body control system to which the technology described herein can be applied.

[0221] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 37, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0222] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0223] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0224] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, a distance measuring device 12031 is connected to the external information detection unit 12030. The distance measuring device 12031 includes the distance measuring device 1000 described above. The external information detection unit 12030 causes the distance measuring device 12031 to measure the distance to an object outside the vehicle (subject S) and acquires the distance data obtained thereby. Based on the acquired distance data, the external information detection unit 12030 may perform object detection processing for people, cars, obstacles, signs, etc.

[0225] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that captures images of the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0226] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including vehicle collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0227] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0228] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0229] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 37, the output devices include an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

[0230] Figure 38 shows an example of the installation location of the distance measuring device 12031.

[0231] In Figure 38, the vehicle 12100 has distance measuring devices 12101, 12102, 12103, 12104, and 12105 as a distance measuring device 12031.

[0232] Distance measuring devices 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. Distance measuring device 12101 installed on the front nose and distance measuring device 12105 installed on the upper part of the windshield inside the vehicle mainly acquire data in front of the vehicle 12100. Distance measuring devices 12102 and 12103 installed on the side mirrors mainly acquire data to the sides of the vehicle 12100. Distance measuring device 12104 installed on the rear bumper or back door mainly acquires data behind the vehicle 12100. The forward data acquired by distance measuring devices 12101 and 12105 is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, etc.

[0233] Figure 38 shows an example of the detection ranges of distance measuring devices 12101 to 12104. Detection range 12111 indicates the detection range of distance measuring device 12101 installed on the front nose, detection ranges 12112 and 12113 indicate the detection ranges of distance measuring devices 12102 and 12103 installed on the side mirrors, respectively, and detection range 12114 indicates the detection range of distance measuring device 12104 installed on the rear bumper or back door.

[0234] For example, the microcomputer 12051, based on distance data obtained from distance measuring devices 12101 to 12104, can determine the distance to each object within the detection range 12111 to 12114 and the temporal change of this distance (relative speed to the vehicle 12100). In particular, it can extract the nearest object on the vehicle 12100's path that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0235] For example, the microcomputer 12051 can use distance data obtained from distance measuring devices 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid a collision by outputting a warning to the driver via the audio speaker 12061 or display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0236] The above describes an example of a mobile control system to which the technology described herein may be applied. The technology described herein may be applied to the distance measuring device 12031 of the configuration described above.

[0237] Furthermore, this technology can also take the following configurations: (1) A light-emitting element comprising: a substrate; a laminated structure disposed on the substrate, wherein a plurality of layers including a light-emitting layer are laminated; and a buffer layer disposed between the substrate and the laminated structure, wherein the buffer layer is made of a material different from the material of the substrate. (2) The light-emitting element according to (1), wherein the material of the buffer layer has a higher thermal decomposition temperature than the material of the substrate. (3) The light-emitting element according to (1) or (2), wherein the substrate and the buffer layer are made of the same material. (4) The light-emitting element according to any one of (1) to (3), wherein at least the buffer layer among the substrate and the buffer layer is made of a compound semiconductor containing Al. (5) Both the substrate and the buffer layer are made of Al ｘ Ga １－ｘ (1) to (4) a light-emitting element according to any one of the following, comprising As (0 ≤ x ≤ 1), wherein the buffer layer has an Al composition x higher than that of the substrate. (6) A light-emitting element according to any one of the following, comprising GaAs, wherein the substrate is made of AlGaAs, and the buffer layer is made of AlGaAs. (7) The carrier concentration of at least a portion of the buffer layer is 1 × 10 １７ cm －３ The above 3 x 10 １９ cm －３The following are the light-emitting elements according to any one of (1) to (6): (8) The light-emitting elements according to any one of (1) to (7), wherein the buffer layer has a p-type conductivity. (9) The light-emitting elements according to (8), wherein the p-type impurity contained in the buffer layer is C. (10) The light-emitting elements according to any one of (1) to (9), wherein the total thickness of the buffer layer is 50 nm or more. (11) The light-emitting elements according to any one of (1) to (10), wherein the buffer layer has a plurality of stacked AlGaAs layers. (12) The light-emitting elements according to (11), wherein at least two of the plurality of AlGaAs layers have different Al compositions. (13) The light-emitting elements according to (11) or (12), wherein at least two of the plurality of AlGaAs layers have different carrier concentrations. (14) At least one of the plurality of AlGaAs layers has a carrier concentration of 1 × 10 １７ cm －３ The above 3 x 10 １９ cm －３ A light-emitting element according to any one of (11) to (13) below. (15) A light-emitting element according to any one of (1) to (14), wherein the plurality of layers have reflectors on one side and / or the other side of the light-emitting layer. (16) A light-emitting element according to (15), wherein the reflectors include multilayer reflectors. (17) An electronic device comprising a light-emitting element, comprising: a substrate; a laminated structure disposed on the substrate, wherein a plurality of layers including a light-emitting layer are laminated; and a buffer layer disposed between the substrate and the laminated structure, wherein the buffer layer is made of a material different from the material of the substrate. (18) A method for manufacturing a light-emitting element, comprising: growing a buffer material different from the substrate material which is the material of the substrate on the substrate to form a buffer layer; and laminating a plurality of layers including a light-emitting layer on the buffer layer. (19) A method for manufacturing a light-emitting element according to (18), wherein the buffer material has a higher thermal decomposition temperature than the substrate material, and in the step of forming the buffer layer, the buffer material is grown at a growth temperature higher than the thermal decomposition temperature of the substrate material. (20) The buffer material is a doping material for doping C, CBr ４ or CBrCl ３A method for manufacturing a light-emitting element according to (18) or (19), using (21) an electronic device comprising a light-emitting element according to any one of (1) to (20).

[0238] 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140: Light-emitting element 101: Substrate 102: Buffer layer 102A: AlGaAs layer 102B: AlGaAs layer 102C: AlGaAs layer 103: First contact layer 104: First semiconductor multilayer reflector layer 105: Light-emitting layer 106: Oxidation constriction layer 107: Second semiconductor multilayer reflector layer 108: Second contact layer LS: Stacked structure

Claims

1. A light-emitting element comprising: a substrate; a laminated structure disposed on the substrate, wherein a plurality of layers including a light-emitting layer are laminated; and a buffer layer disposed between the substrate and the laminated structure, the buffer layer being made of a material different from the material of the substrate.

2. The light-emitting element according to claim 1, wherein the material of the buffer layer has a higher thermal decomposition temperature than the material of the substrate.

3. The light-emitting element according to claim 2, wherein the substrate and the buffer layer are made of the same material.

4. The light-emitting element according to claim 2, wherein at least the buffer layer among the substrate and the buffer layer is made of a compound semiconductor containing Al.

5. Both the substrate and the buffer layer are made of Al ｘ Ga １－ｘ The light-emitting element according to claim 1, comprising As (0 ≤ x ≤ 1), wherein the buffer layer has a higher Al composition x than the substrate.

6. The light-emitting element according to claim 1, wherein the substrate is made of GaAs and the buffer layer is made of AlGaAs.

7. The carrier concentration of at least a portion of the buffer layer is 1 × 10⁻⁶ １７ cm －３ The above 3 x 10 １９ cm －３ The following is the light-emitting element according to claim 1.

8. The light-emitting element according to claim 1, wherein the buffer layer has a p-type conductivity.

9. The light-emitting element according to claim 8, wherein the p-type impurity contained in the buffer layer is C.

10. The light-emitting element according to claim 1, wherein the total thickness of the buffer layer is 50 nm or more.

11. The light-emitting element according to claim 1, wherein the buffer layer has a plurality of stacked AlGaAs layers.

12. The light-emitting element according to claim 11, wherein at least two of the plurality of AlGaAs layers have different Al compositions.

13. The light-emitting element according to claim 11, wherein at least two of the plurality of AlGaAs layers have different carrier concentrations.

14. At least one of the plurality of AlGaAs layers has a carrier concentration of 1×10 １７ cm －３ -3 or more and 3×10 １９ cm －３ -3 or less, the light-emitting element according to claim 11.

15. The light-emitting element according to claim 1, wherein the plurality of layers have reflectors on one side and / or the other side of the light-emitting layer.

16. The light-emitting element according to claim 15, wherein the reflector includes a multilayer reflector.

17. An electronic device comprising a light-emitting element, the light-emitting element comprising: a substrate; a laminated structure disposed on the substrate, wherein a plurality of layers including a light-emitting layer are laminated; and a buffer layer disposed between the substrate and the laminated structure, the buffer layer being made of a material different from the material of the substrate.

18. A method for manufacturing a light-emitting element, comprising the steps of: growing a buffer material different from the substrate material on a substrate to form a buffer layer; and stacking a plurality of layers including a light-emitting layer on the buffer layer.

19. The method for manufacturing a light-emitting element according to claim 18, wherein the buffer material has a higher thermal decomposition temperature than the substrate material, and in the step of forming the buffer layer, the buffer material is grown at a growth temperature higher than the thermal decomposition temperature of the substrate material.

20. The buffer material is provided with CBr as a doping material for doping with C. ４ or CBrCl ３ A method for manufacturing an luminescent element according to claim 18, using the method described above.

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