Light-emitting device and method for manufacturing same

Abstract

A light-emitting device (1000) comprises: a ScAlMgO4 substrate (1011) including a first surface (1011_1) and a second surface (1011_2) on the reverse side of the first surface (1011_1); an undoped nitride semiconductor layer (1030) on the second surface (1011_2) of the ScAlMgO4 substrate (1011); and a light-emitting layer (1050) on the undoped nitride semiconductor layer (1030). The light-emitting layer (1050) has an MQW structure in which well layers (1051) containing InxGa(1-x)N (0.3 ≤ x ≤ 0.5) and barrier layers (1052) containing InyGa(1-y)N (0 < y < x) are alternately laminated, and a surface relief pattern is provided on the side of the first surface (1011_1).

Description

Light emitting device and method for manufacturing the same

[0001] An embodiment of the present invention relates to a light emitting device using a nitride semiconductor, and also to a method for manufacturing a light emitting device using a nitride semiconductor.

[0002] Nitride semiconductors such as GaN and InGaN are widely used as light-emitting layers with a multiple quantum well (MQW) structure in blue or green light-emitting diodes. When using a nitride semiconductor as the light-emitting layer in a red light-emitting diode, a high In content is required. However, in the case of nitride semiconductors deposited at high temperatures by metalorganic chemical vapor deposition (MOCVD), increasing the In content in the nitride semiconductor leads to phase separation and reduced luminous efficiency. Furthermore, increasing the In content in an MQW structure leads to polarization due to lattice strain between the well and barrier layers. As a result, current dependence due to the quantum-confined Stark effect occurs, shifting the emission wavelength to shorter wavelengths.

[0003] Recently, ScAlMgO, which has a small lattice mismatch with nitride semiconductors, has been ４ Light-emitting diodes using substrates have been developed (see, for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2020-9914

[0005] However, ScAlMgO ４ Even when a light-emitting diode is manufactured using the substrate, if the In ratio in the nitride semiconductor film formed by MOCVD is increased, phase separation occurs in the nitride semiconductor, resulting in a decrease in light-emitting efficiency.

[0006] In view of the above problems, one embodiment of the present invention has an object to provide a light-emitting device in which a decrease in the luminous efficiency of the light-emitting layer is suppressed and light extraction efficiency is improved. Another embodiment of the present invention has an object to provide a method for manufacturing a light-emitting device in which a decrease in the luminous efficiency of the light-emitting layer is suppressed and light extraction efficiency is improved.

[0007] A light emitting device according to one embodiment of the present invention includes a ScAlMgO ４a substrate and ScAlMgO ４ an undoped nitride semiconductor layer on the second surface of the substrate; and a light emitting layer on the undoped nitride semiconductor layer, the light emitting layer comprising In ｘ Ga （１－ｘ） A well layer containing N (0.30≦x≦0.50) and In ｙ Ga （１－ｙ） The semiconductor device has an MQW structure in which barrier layers containing N (0<y<x) are alternately stacked, and a concave-convex pattern is provided on the first surface side.

[0008] A method for manufacturing a light emitting device according to one embodiment of the present invention includes the steps of: ４ A degassing prevention layer is formed on the first surface of the support substrate, and the degassing prevention layer is formed of ScAlMgO ４ An undoped nitride semiconductor layer is formed on a second surface of the support substrate opposite to the first surface, and In is deposited on the undoped nitride semiconductor layer by sputtering. ｘ Ga （１－ｘ） A well layer containing N (0.30≦x≦0.50) and In ｙ Ga （１－ｙ） and forming a barrier layer containing N (0<y<x) alternately to form a light-emitting layer having an MQW structure.

[0009] FIG. 1 is a schematic cross-sectional view illustrating a configuration of a light-emitting device according to one embodiment of the present invention; FIG. 2 is a schematic cross-sectional view illustrating a configuration of a light-emitting layer of a light-emitting device according to one embodiment of the present invention; FIG. 3 is a flowchart illustrating a method for manufacturing a light-emitting device according to one embodiment of the present invention; FIG. 4 is a schematic cross-sectional view illustrating a method for manufacturing a light-emitting device according to one embodiment of the present invention; FIG. 5 is a schematic cross-sectional view illustrating a method for manufacturing a light-emitting device according to one embodiment of the present invention; FIG. 6 is a schematic cross-sectional view illustrating a method for manufacturing a light-emitting device according to one embodiment of the present invention; FIG. 7 is a schematic cross-sectional view illustrating a method for manufacturing a light-emitting device according to one embodiment of the present invention; FIG. 8 is a schematic cross-sectional view illustrating a method for manufacturing a light-emitting device according to one embodiment of the present invention; FIG. 9 is a schematic cross-sectional view illustrating a method for manufacturing a light-emitting device according to one embodiment of the present invention; ４ 1 is a flowchart illustrating a cleavage process for a support substrate in a method for manufacturing a light emitting device according to an embodiment of the present invention. ４ 1 is a schematic cross-sectional view illustrating a cleavage process of a support substrate, in a method for manufacturing a light-emitting device according to an embodiment of the present invention. ４ While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments and is not to be construed as limiting the invention.

[0010] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. Note that each embodiment is merely an example, and any embodiment that a person skilled in the art could easily come up with by making appropriate modifications while maintaining the gist of the invention is naturally included in the scope of the present invention. Furthermore, in order to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment. However, the illustrated shapes are merely examples and do not limit the interpretation of the present invention.

[0011] In this specification, unless otherwise specified, expressions such as "α includes A, B, or C," "α includes any of A, B, and C," and "α includes one selected from the group consisting of A, B, and C" do not exclude cases where α includes multiple combinations of A to C. Furthermore, these expressions do not exclude cases where α includes other components.

[0012] In this specification, for the sake of convenience, the terms "above" or "upper" or "below" or "belower" are used. In principle, the substrate on which the structure is formed is used as the reference, and the direction from the substrate toward the structure is referred to as "above" or "upper." Conversely, the direction from the structure toward the substrate is referred to as "below" or "belower." Therefore, in the expression "structure on a substrate," the surface of the structure facing the substrate is the lower surface of the structure, and the surface opposite to that is the upper surface of the structure. Furthermore, the expression "structure on a substrate" merely describes the hierarchical relationship between the substrate and the structure, and other components may be disposed between the substrate and the structure. Furthermore, the terms "above" or "upper" or "below" or "belower" refer to the stacking order in a structure in which multiple layers are stacked, and do not necessarily have to be in an overlapping positional relationship in a planar view.

[0013] In this specification, the letters "first," "second," or "third" attached to elements are convenient labels used to distinguish elements and have no other meaning unless otherwise specified.

[0014] In this specification and drawings, the same reference numeral is used to collectively represent multiple identical or similar components, and capital letters may be added to distinguish between the multiple components. Furthermore, a hyphen and a natural number may be used to distinguish between multiple parts of a single component.

[0015] In this specification, the terms "film" and "layer" may be used interchangeably in some cases.

[0016] In this specification, the term "nitride semiconductor" refers to a III-V semiconductor that contains nitrogen. Examples of "nitride semiconductor" include gallium nitride (GaN) and indium gallium nitride (InGaN).

[0017] In this specification, the term "undoped nitride semiconductor" refers to a nitride semiconductor to which no impurities have been added. A nitride semiconductor to which impurities have been added and which is imparted with electrical conductivity will be described as a "p-type nitride semiconductor" or an "n-type nitride semiconductor."

[0018] In this specification, the term "light-emitting device" refers to any device that includes a light-emitting element. For example, the term "light-emitting device" includes a lighting device that irradiates light at a specific location and a display device that displays a visual image or video. Furthermore, the term "light-emitting device" may be composed of only a light-emitting element (e.g., an LED chip).

[0019] The following embodiments can be combined with each other unless a technical contradiction occurs.

[0020] First Embodiment A light emitting device 1000 according to one embodiment of the present invention and a method for manufacturing the same will be described with reference to FIGS.

[0021] 1. Configuration of Light-Emitting Device 1000 Fig. 1 is a schematic cross-sectional view showing the configuration of a light-emitting device 1000 according to one embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing the configuration of a light-emitting layer 1050 according to one embodiment of the present invention. Specifically, Fig. 2 is a partially enlarged cross-sectional view of region A shown in Fig. 1.

[0022] As shown in FIG. 1, the light emitting device 1000 is made of ScAlMgO ４ It includes a substrate 1011 , an undoped nitride semiconductor layer 1030 , an n-type nitride semiconductor layer 1040 , a light emitting layer 1050 , a p-type nitride semiconductor layer 1060 , a protective layer 1070 , an n-type electrode 1080 , and a p-type electrode 1090 .

[0023] ScAlMgO ４ A concave-convex pattern is formed on the first surface 1011_1 of the substrate 1011. The undoped nitride semiconductor layer 1030 is made of ScAlMgO ４The protective layer 1070 is provided on and in contact with the second surface 1011_2 of the substrate 1011. The n-type nitride semiconductor layer 1040 is provided on and in contact with the undoped nitride semiconductor layer 1030. A recess 1041 recessed from the upper surface of the n-type nitride semiconductor is formed in the n-type nitride semiconductor layer 1040. The light-emitting layer 1050 is provided on and in contact with the n-type nitride semiconductor layer 1040. The p-type nitride semiconductor layer 1060 is provided on and in contact with the light-emitting layer 1050. The protective layer 1070 is provided so as to cover the end surfaces of the undoped nitride semiconductor layer 1030, the end surfaces of the n-type nitride semiconductor layer 1040, the wall surfaces and bottom surfaces of the recess 1041 in the n-type nitride semiconductor layer 1040, the end surface of the light-emitting layer 1050, and the end surfaces and upper surface of the p-type nitride semiconductor layer 1060. The protective layer 1070 is provided with a first opening 1071 that exposes a portion of the bottom surface of the recess 1041 (i.e., a portion of the n-type nitride semiconductor layer 1040 in the recess 1041) and a second opening 1072 that exposes a portion of the top surface of the p-type nitride semiconductor layer 1060. The n-type electrode 1080 covers the first opening 1071 and is provided on and in contact with the n-type nitride semiconductor layer 1040. The p-type electrode 1090 covers the second opening 1072 and is provided on and in contact with the p-type nitride semiconductor layer 1060.

[0024] [1-1. ScAlMgO ４ Substrate 1011] ScAlMgO ４ The substrate 1011 is made of an oxide containing scandium (Sc), aluminum (Al), and magnesium (Mg) (ScAlMgO ４ ) is a single crystal substrate made of ScAlMgO ４ The lattice constant of ScAlMgO is close to the lattice constant of GaN, and the lattice mismatch is small. ４ The GaN film formed on the substrate 1011 has few defects and is of high quality. ４ The substrate is In ０．１７ Ga ０．８３ Easy to lattice match with N. ScAlMgO ４ In the substrate 1011, ScAlMgO ４ The c-axis of ScAlMgO is oriented. ４The thickness of the substrate 1011 is 5 μm or more and 10 μm or less. ４ If the thickness of the substrate 1011 is within this range, ScAlMgO ４ The light emitted from the end face of the substrate 1011 is reduced, and the ScAlMgO ４ The extraction efficiency of light emitted from the first surface 1011_1 of the substrate 1011 can be improved.

[0025] ScAlMgO ４ A concave-convex pattern is formed on the first surface 1011_1 of the substrate 1011. The light emitted from the light-emitting layer 1050 is ４ The light is emitted from the first surface 1011_1 of the substrate 1011. The light extraction efficiency can be improved by forming a concave-convex pattern on the first surface 1011_1. For example, the height of the concave-convex pattern is 1 μm or more and 3 μm or less.

[0026] [1-2. Undoped Nitride Semiconductor Layer 1030] The undoped nitride semiconductor layer 1030 has the function of improving the crystal quality of the n-type nitride semiconductor layer 1040 formed on the undoped nitride semiconductor layer 1030. It is preferable to use a nitride semiconductor having the same composition as the n-type nitride semiconductor layer 1040 as the undoped nitride semiconductor layer 1030. This reduces the lattice mismatch between the n-type nitride semiconductor layer 1040 and the undoped nitride semiconductor layer 1030, thereby reducing defects in the n-type nitride semiconductor layer formed on the undoped nitride semiconductor layer 1030. For example, the undoped nitride semiconductor layer 1030 may be made of In ０．１７ Ga ０．８３ N can be used.

[0027] [1-3. n-type nitride semiconductor layer 1040] The n-type nitride semiconductor layer 1040 has electron conductivity and functions to transport electrons to the light emitting layer 1050. The nitride semiconductor contained in the n-type nitride semiconductor layer 1040 is doped with impurities such as silicon (Si) or germanium (Ge). The impurities are activated in the nitride semiconductor to form the n-type nitride semiconductor layer 1040 having electron conductivity. For example, the n-type nitride semiconductor layer 1040 may be formed by using an InN nitride semiconductor doped with Si. ０．１７Ga ０．８３ N can be used. There is no particular limitation on the thickness of n-type nitride semiconductor layer 1040. For example, the thickness of n-type nitride semiconductor layer 1040 is 500 nm or more and 3000 nm or less.

[0028] As described above, the recess 1041 is formed in the n-type nitride semiconductor layer 1040. There is no particular limitation on the depth of the recess 1041. For example, the depth of the recess 1041 is 300 nm or less from the upper surface of the n-type nitride semiconductor layer 1040.

[0029] [1-4. Light-Emitting Layer 1050] The light-emitting layer 1050 has a function of emitting light by recombining electrons transported from the n-type nitride semiconductor layer 1040 and holes transported from the p-type nitride semiconductor layer 1060. As shown in FIG. 2, the light-emitting layer 1050 has a so-called multiple quantum well (MQW) structure in which well layers 1051 and barrier layers 1052 are alternately stacked. Each of the well layers 1051 and the barrier layers 1052 uses a nitride semiconductor. For example, the well layer 1051 may be made of In ｘ Ga （１－ｘ） In this embodiment, the well layer 1051 contains a large proportion of In so that the light emitting device 1000 can emit light in the long wavelength region of the visible light range (for example, yellow or red). Specifically, the value of x is 0.30 or more and 0.50 or less, preferably 0.32 or more and 0.46 or less, more preferably 0.34 or more and 0.42 or less, and particularly preferably 0.36 or more and 0.40 or less. A nitride semiconductor having a band gap larger than that of the nitride semiconductor of the well layer 1051 is used as the barrier layer 1052. For example, the barrier layer 1052 may contain In ｘ Ga （１－ｘ） N (0<y<x) can be used.

[0030] [1-5. p-type nitride semiconductor layer 1060] The p-type nitride semiconductor layer 1060 has hole conductivity and functions to transport holes to the light emitting layer 1050. The nitride semiconductor contained in the p-type nitride semiconductor layer 1060 is doped with impurities such as magnesium (Mg). The impurities are activated in the nitride semiconductor to form the p-type nitride semiconductor layer 1060 having hole conductivity. For example, the p-type nitride semiconductor layer 1060 may be formed by using InN doped with Mg. ０．１７ Ga ０．８３ N can be used. There is no particular limitation on the thickness of n-type nitride semiconductor layer 1040. For example, the thickness of p-type nitride semiconductor layer 1060 is 100 nm or more and 500 nm or less.

[0031] [1-6. Protective Layer 1070] The protective layer 1070 has a function of suppressing the intrusion of impurities (for example, moisture) from the outside and protecting the undoped nitride semiconductor layer 1030, the n-type nitride semiconductor layer 1040, the light emitting layer 1050, and the p-type nitride semiconductor layer 1060. For example, silicon oxide, silicon nitride, aluminum oxide, or the like can be used as the protective layer 1070. The protective layer 1070 may have a single layer structure or a laminated structure. For example, when the protective layer 1070 has a laminated structure, the protective layer 1070 may be a laminated film (Al ２ O ３ / SiO ２ The protective layer 1070 may be a silicon nitride (SiN) film.

[0032] [1-7. n-Type Electrode 1080] The n-type electrode 1080 has the function of injecting electrons into the n-type nitride semiconductor layer 1040. For example, a layered structure (Au / Al / Ti) of titanium (Ti), aluminum (Al), and gold (Au) from the bottom up, or an alloy of these, can be used as the n-type electrode 1080. The n-type electrode 1080 may have a single-layer structure or a layered structure.

[0033] [1-8. p-Type Electrode 1090] The p-type electrode 1090 has a function of injecting holes into the p-type nitride semiconductor layer 1060. For example, the p-type electrode 1090 can be made of a layered structure of nickel (Ni) and gold (Au), a layered structure of platinum (Pt) and gold (Au), a layered structure of palladium (Pd) and gold (Au), indium tin oxide (ITO), chromium (Cr), or an alloy thereof. The p-type electrode 1090 may have a single-layer structure or a layered structure.

[0034] 3 is a flowchart illustrating a method for manufacturing the light emitting device 1000 according to one embodiment of the present invention. Figures 4 to 13 are schematic cross-sectional views illustrating a method for manufacturing the light emitting device 1000 according to one embodiment of the present invention.

[0035] 3, the method for manufacturing the light emitting device 1000 includes steps S1000 to S1120. Steps S1000 to S1120 will be described below in order with reference to FIGS.

[0036] In step S1000, ScAlMgO ４ An anti-degassing layer 1020 is formed on the first surface 1010_1 of the support substrate 1010 (see FIG. 4). ４ The substrate 1011 is made of ScAlMgO ４ The degassing prevention layer 1020 is a part of the support substrate 1010. When the substrate is heated during the deposition of the nitride semiconductor film in the manufacturing process of the light emitting device 1000, the degassing prevention layer 1020 is formed between the substrate stage and the ScAlMgO ４ By contacting the support substrate 1010, for example, ScAlMgO ４ Scratches or chips may be formed on the first surface 1010_1 of the support substrate 1010. In this case, the ScAlMgO ４ Mg is lost from the support substrate 1010, and Mg is mixed as an impurity into the nitride semiconductor film during film formation. ４A degassing prevention layer 1020 is formed as a protective film on the first surface 1010_1 of the support substrate 1010. This can prevent scratches or chips from occurring on the substrate. For example, aluminum nitride or the like is used as the degassing prevention layer 1020. The degassing prevention layer 1020 can be formed by chemical vapor deposition (CVD), sputtering, or the like.

[0037] In step S1010, ScAlMgO ４ An undoped nitride semiconductor layer 1030 is formed on a second surface 1010_2 opposite to the first surface 1010_1 of the support substrate 1010 (see FIG. 5 ). The undoped nitride semiconductor layer 1030 can be formed by metal-organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), or the like.

[0038] In step S1020, an n-type nitride semiconductor layer 1040 is formed on the undoped nitride semiconductor layer 1030 (see FIG. 6). The n-type nitride semiconductor layer 1040 can be formed by MOCVD, ALD, or the like.

[0039] In step S1030, the light-emitting layer 1050 is formed on the n-type nitride semiconductor layer 1040 (see FIG. 7 ). Specifically, the light-emitting layer 1050 is formed by alternately depositing nitride semiconductor well layers 1051 and nitride semiconductor barrier layers 1052 by sputtering. As described above, in this embodiment, the light-emitting layer 1050 is formed by sputtering. Because sputtering allows deposition at a lower temperature than MOCVD or ALD, the nitride semiconductor film deposited by sputtering can contain a high In composition. In other words, even if the nitride semiconductor film deposited by sputtering contains a high In composition, phase separation is unlikely to occur within the nitride semiconductor film. Therefore, the nitride semiconductor film of the light-emitting layer 1050 has few crystal defects and is a high-quality film.

[0040] In forming a nitride semiconductor film by sputtering, a nitride semiconductor can be used as a sputtering target, and nitrogen gas or a mixed gas of nitrogen and argon can be used as a sputtering gas. The sputtering may be RF sputtering or pulse sputtering.

[0041] In step S1040, a p-type nitride semiconductor layer 1060 is formed on the light emitting layer 1050 (see FIG. 8). The p-type nitride semiconductor layer 1060 can be formed by MOCVD, ALD, or the like.

[0042] In step S1050, a first heat treatment is performed. The first heat treatment is a heat treatment mainly for activating impurities added to the nitride semiconductor of p-type nitride semiconductor layer 1060. The first heat treatment improves the conductivity of p-type nitride semiconductor layer 1060.

[0043] In step S1060, ScAlMgO ４ Each layer deposited on the second surface 1010_2 of the support substrate 1010 is processed into a predetermined pattern shape (see FIG. 9 ). Specifically, patterning is performed by photolithography so that the end face of the undoped nitride semiconductor layer 1030, the end face of the n-type nitride semiconductor layer 1040, the end face of the light emitting layer 1050, and the end face of the p-type nitride semiconductor layer 1060 are exposed. In addition, recesses 1041 are formed in the n-type nitride semiconductor layer 1040 during the patterning process.

[0044] In step S1070, a protective layer 1070 is formed so as to cover the end faces of the undoped nitride semiconductor layer 1030, the end faces of the n-type nitride semiconductor layer 1040, the wall and bottom surfaces of the recess 1041 in the n-type nitride semiconductor layer 1040, the end face of the light emitting layer 1050, and the end faces and top surface of the p-type nitride semiconductor layer 1060 (see FIG. 10 ). The protective layer 1070 can be formed by electron beam evaporation, CVD, sputtering, or the like. Furthermore, a first opening 1071 is formed in the protective layer 1070 by photolithography so as to expose the n-type nitride semiconductor layer 1040, and a second opening 1072 is formed so as to expose the p-type nitride semiconductor layer 1060.

[0045] In step S1080, an n-type electrode 1080 is formed on the n-type nitride semiconductor layer 1040 so as to cover the first opening 1071 (see FIG. 11 ). The n-type electrode 1080 can be formed by sputtering or the like. Alternatively, the n-type electrode 1080 is processed into a predetermined pattern shape by photolithography. Alternatively, the n-type electrode 1080 may be formed using a lift-off method.

[0046] In step S1090, a p-type electrode 1090 is formed on the p-type nitride semiconductor layer 1060 so as to cover the second opening 1072 (see FIG. 12 ). The p-type electrode 1090 can be formed by sputtering or the like. Alternatively, the p-type electrode 1090 is processed into a predetermined pattern shape by photolithography. Alternatively, the p-type electrode 1090 may be formed using a lift-off method.

[0047] Note that steps S1080 and S1090 may be performed in the reverse order, and the n-type electrode 1080 may be formed after the p-type electrode 1090 is formed.

[0048] In step S1100, a second heat treatment is performed. The second treatment is a heat treatment mainly for improving the interfaces between the n-type nitride semiconductor layer 1040 and the n-type electrode 1080 and between the p-type nitride semiconductor layer 1060 and the p-type electrode 1090. The second heat treatment reduces the contact resistance between the n-type nitride semiconductor layer 1040 and the n-type electrode 1080 and between the p-type nitride semiconductor layer 1060 and the p-type electrode 1090.

[0049] In step S1110, ScAlMgO ４ The support substrate 1010 is cleaved (see FIG. 13). Step S1110 will now be described in detail with reference to FIGS.

[0050] FIG. 14 shows a method for manufacturing a light emitting device 1000 according to an embodiment of the present invention. ４ 15 and 16 are flowcharts illustrating a cleavage process for the support substrate 1010. ４10A and 10B are schematic cross-sectional views illustrating a cleavage process of a support substrate 1010.

[0051] In step S1111, ScAlMgO ４ A notch 1013 is formed on the end surface of the support substrate 1010 (see FIG. 15). ４ The ScAlMgO ４ The cutout 1013 may be formed by irradiating the end surface of the support substrate 1010 with a laser.

[0052] In step S1112, ScAlMgO ４ Compressive stress is applied to the end surface of the support substrate 1010 (FIG. 16). ４ has a cleavage plane parallel to the c-axis. ４ In the support substrate 1010, ScAlMgO ４ Therefore, when compressive stress is applied, the c-axis of ScAlMgO ４ The support substrate 1010 is cleaved from the notch 1013 .

[0053] ScAlMgO ４ In the cleavage process of the support substrate 1010, the notch 1013 is formed and the ScAlMgO ４ In some cases, particles may be generated during cleavage. ４ It is preferable that the second surface 1010_2 side of the support substrate 1010 is protected. For example, ScAlMgO ４ A resist is applied to the second surface 1010_2 side of the support substrate 1010, or a resist film is attached to form a resist layer, thereby forming a ScAlMgO ４ Each layer on the second surface 1010_2 of the support substrate 1010 can be protected.

[0054] The above-described ScAlMgO ４ By cleaving the support substrate 1010, ScAlMgO ４ The support substrate 1010 is made of ScAlMgO ４Substrate 1011 and ScAlMgO ４ The ScAlMgO substrate 1012 is separated from the degassing prevention layer 1020. ４ The substrate 1011 is removed and ScAlMgO ４ The first surface 1011_1 of the substrate 1011 is exposed (ScAlMgO ４ The second surface 1011_2 of the substrate 1011 is made of ScAlMgO ４ This corresponds to the second surface 1010_2 of the support substrate 1010. Note that the ScAlMgO ４ The substrate 1011 is a ScAlMgO substrate for manufacturing another light emitting device 1000. ４ It can be reused as the support substrate 1010 .

[0055] In step S1120, ScAlMgO ４ A concave-convex pattern is formed on the first surface 1011_1 of the substrate 1011. The concave-convex pattern is formed by photolithography. ４ In the cleavage process of the support substrate 1010, ScAlMgO ４ If a resist layer is formed on the second surface 1011_2 side of the substrate 1011, step S1120 can be performed without removing the resist layer in step S1110. ４ If a resist layer is formed on the second surface 1011_2 side of the substrate 1011, the ScAlMgO ４ It is possible to protect each layer on the second surface 1011_2 side of the substrate 1011. ScAlMgO ４ can be etched using hydrofluoric acid. ２ O ３ has high etching resistance to hydrofluoric acid. ２ O ３ is difficult to be etched by hydrofluoric acid. ２ O ３ When it contains ScAlMgO ４ Each layer on the second surface 1011_2 side of the substrate 1011 can be sufficiently protected.

[0056] The method for manufacturing light emitting device 1000 has been described based on the flowcharts shown in Figures 3 and 14, but the method for manufacturing light emitting device 1000 is not limited to the steps shown in the flowcharts of Figures 3 and 14. Light emitting device 1000 may be manufactured using a manufacturing method in which the order of steps S1000 to S1120 is reversed, or may be manufactured using a manufacturing method that includes steps other than steps S1000 to S1120.

[0057] Although not described further, not only the light emitting layer 1050 but also one or more of the undoped nitride semiconductor layer 1030, the n-type nitride semiconductor layer 1040, and the p-type nitride semiconductor layer 1060 may be deposited by sputtering. In this case, the undoped nitride semiconductor layer 1030, the n-type nitride semiconductor layer 1040, and the p-type nitride semiconductor layer 1060 can be deposited at low temperatures, and therefore the In ratio of the nitride semiconductors contained in the undoped nitride semiconductor layer 1030, the n-type nitride semiconductor layer 1040, and the p-type nitride semiconductor layer 1060 can be increased.

[0058] Although not shown, ScAlMgO ４ A buffer layer may be provided on the second surface 1010_2 of the support substrate 1010. When the undoped nitride semiconductor layer 1030 includes a nitride semiconductor with a high In ratio that is deposited by sputtering, the c-axis orientation of the undoped nitride semiconductor layer 1030 can be controlled by providing a buffer layer. Because the undoped nitride semiconductor layer 1030 is provided on the buffer layer, a conductive material or an insulating material may be used as the buffer layer. The buffer layer is deposited by CVD or sputtering.

[0059] For example, the conductive material of the buffer layer may be titanium (Ti), titanium nitride (TiN), or the like. ｘ ), titanium oxide (TiO ｘ ), graphene, zinc oxide (ZnO), magnesium diboride (MgB ２), aluminum (Al), silver (Ag), calcium (Ca), nickel (Ni), copper (Cu), strontium (Sr), rhodium (Rh), palladium (Pd), cerium (Ce), ytterbium (Yb), iridium (Ir), platinum (Pt), gold (Au), lead (Pb), actinium (Ac), or thorium (Th) can be used. In particular, it is preferable to use Ti, graphene, or ZnO as the material for the buffer layer.

[0060] Alternatively, silicon (Si), germanium (Ge), or an alloy thereof may be used as the conductive material for the buffer layer. Silicon and germanium are semiconductor materials, but have higher conductivity than insulating materials, which will be described later. Therefore, in this specification, semiconductor materials such as silicon and germanium used as the buffer layer will be described as conductive materials.

[0061] Furthermore, for example, the insulating material of the buffer layer may be aluminum nitride (AlN), aluminum oxide (Al ２ O ３ ), lithium niobate (LiNbO), BiLaTiO, SrFeO, SrFeO, BiFeO, BaFeO, ZnFeO, PMnN-PZT, or biological apatite (BAp) can be used. In particular, it is preferable to use AlN as the buffer layer.

[0062] In this embodiment, the light emitting layer 1050 is formed by sputtering, which allows film formation at low temperatures, and therefore phase separation in the nitride semiconductor of the light emitting layer 1050 is suppressed, and the In ratio in the nitride semiconductor can be increased. Therefore, the light emitting device 1000 can emit red light from the light emitting layer 1050 containing a nitride semiconductor. Furthermore, even when the light emitting device 1000 emits red light, the high crystal quality of the light emitting layer 1050 can suppress a decrease in the light emitting efficiency of the light emitting device 1000. Furthermore, the ScAlMgO ４ A concavo-convex pattern for improving light extraction efficiency is formed on the first surface 1011_1 of the substrate 1011. Therefore, the light emitting device 1000 according to this embodiment has improved light extraction efficiency.

[0063] Second Embodiment A light emitting device 1000A according to one embodiment of the present invention will be described with reference to Fig. 17. In the following, when the configuration of the light emitting device 1000A is the same as that of the light emitting device 1000, the description of the configuration of the light emitting device 1000A may be omitted.

[0064] FIG. 17 is a schematic cross-sectional view showing the configuration of a light emitting device 1000A according to one embodiment of the present invention.

[0065] As shown in FIG. 17, the light emitting device 1000A is made of ScAlMgO ４ It includes a substrate 1011 , an optical adjustment layer 1100A, an undoped nitride semiconductor layer 1030 , an n-type nitride semiconductor layer 1040 , a light emitting layer 1050 , a p-type nitride semiconductor layer 1060 , a protective layer 1070 , an n-type electrode 1080 , and a p-type electrode 1090 .

[0066] The optical adjustment layer 1100A is made of ScAlMgO ４ The optical adjustment layer 1100A is provided on the first surface 1011_1 of the substrate 1011. The surface of the optical adjustment layer 1100A has an uneven pattern. For example, the optical adjustment layer 1100A can be made of silicon oxide (refractive index 1.46), polysiloxane (refractive index 1.43), or polysilazane (refractive index 1.55). The surface of the optical adjustment layer 1100A has an uneven pattern. The uneven pattern can be formed by photolithography after the optical adjustment layer 1100A is formed.

[0067] The optical adjustment layer 1100A can be formed by CVD or sputtering if it is made of a low molecular weight material such as silicon oxide, or by coating if it is made of a high molecular weight material such as polysiloxane or polysilazane.

[0068] The optical adjustment layer 1100A is made of ScAlMgO ４ ScAlMgO, which has a lower refractive index than the substrate 1011 ４ It has the function of improving the extraction efficiency of light that passes through the substrate 1011 and the optical adjustment layer 1100A and is emitted to the outside.

[0069] In this embodiment, the light emitted from the light emitting layer 1050 is transmitted through the n-type nitride semiconductor layer 1040, the undoped nitride semiconductor layer 1030, and the ScAlMgO ４ The light passes through the substrate 1011 and the optical adjustment layer 1100A and is emitted to the outside. The refractive index of the layers through which the light passes is approximately 2.3 (the refractive index of the n-type nitride semiconductor layer 1040 and the undoped nitride semiconductor layer 1030), 1.9 (the refractive index of the ScAlMgO ４ The refractive index of the substrate 1011 can be reduced to 1.4 to 1.6 (the refractive index of the optical adjustment layer 1100A) in that order. In addition, a concavo-convex pattern that improves the light extraction efficiency is formed on the surface of the optical adjustment layer 1100A. Therefore, the light extraction efficiency of the light emitting device 1000A according to this embodiment is improved.

[0070] Third Embodiment A light emitting device 1000B according to one embodiment of the present invention will be described with reference to Fig. 18. In the following, when the configuration of the light emitting device 1000B is the same as that of the light emitting device 1000, the description of the configuration of the light emitting device 1000B may be omitted.

[0071] As shown in FIG. 18, the light emitting device 1000B is made of ScAlMgO ４ It includes a substrate 1011 , a glass substrate 1110B, an undoped nitride semiconductor layer 1030 , an n-type nitride semiconductor layer 1040 , a light emitting layer 1050 , a p-type nitride semiconductor layer 1060 , a protective layer 1070 , an n-type electrode 1080 , and a p-type electrode 1090 .

[0072] The glass substrate 1110B is made of ScAlMgO ４ The adhesive layer 1120B is provided on the first surface 1011_1 of the substrate 1011. The adhesive layer 1120B is formed by bonding the glass substrate 1110B to the ScAlMgO ４ The cleaved and exposed ScAlMgO film shown in FIG. ４An acrylic adhesive or the like is applied to the first surface 1011_1 of the substrate 1011, and then the glass substrate 1110B is attached to the substrate 1011, thereby manufacturing the light emitting device 1000B. The surface of the glass substrate 1110B has an uneven pattern. The uneven pattern may be formed before or after the glass substrate 1110B is attached.

[0073] The glass substrate 1110B is amorphous and does not generally have a crystalline structure, but a crystalline structure may exist in a minute region. The upper limit of the thermal expansion coefficient of the glass substrate 1110B is 4.2×10 －６ / K, preferably less than 4.0 × 10 －６ / K. The lower limit of the thermal expansion coefficient of the glass substrate 1110B is 3.0×10 －６ / K, preferably 3.5 × 10 －６ / K. The glass substrate 1110B preferably has a low content of alkali metal components to prevent contamination of the light-emitting layer 1050. For example, the content of alkali metals in the glass substrate 1110B is 0.1 mass % or less. For example, an amorphous glass material made of aluminoborosilicate glass or aluminosilicate glass can be used as the glass substrate 1110B.

[0074] The thickness of the glass substrate 1110B is not particularly limited. ４ In order to reduce the warpage of the substrate 1011, the thickness of the glass substrate 1110B is set to ScAlMgO ４ It is preferable that the thickness of glass substrate 1110B is sufficiently larger than the total film thickness of substrate 1011, undoped nitride semiconductor layer 1030, n-type nitride semiconductor layer 1040, light emitting layer 1050, and p-type nitride semiconductor layer 1060. For example, the thickness of glass substrate 1110B is 50 times or more the total film thickness of undoped nitride semiconductor layer 1030, n-type nitride semiconductor layer 1040, light emitting layer 1050, and p-type nitride semiconductor layer 1060. Specifically, the thickness of glass substrate 1110B is 0.5 mm or more and 1.0 mm or less.

[0075] In this embodiment, the light emitted from the light emitting layer 1050 is transmitted through the n-type nitride semiconductor layer 1040, the undoped nitride semiconductor layer 1030, and the ScAlMgO ４ The light passes through the substrate 1011, the adhesive layers 1120B, and 1110B and is emitted to the outside. The refractive index of the layers through which the light passes is approximately 2.3 (the refractive index of the n-type nitride semiconductor layer 1040 and the undoped nitride semiconductor layer 1030), 1.9 (the refractive index of the ScAlMgO ４ The refractive index can be decreased in the order of 1.52 to 1.55 (refractive index of the adhesive layer 1120B), 1.52 to 1.55 (refractive index of the substrate 1011), and 1.51 (refractive index of the glass substrate 1110B). In addition, an uneven pattern that improves light extraction efficiency is formed on the surface of the glass substrate 1110B. Therefore, the light extraction efficiency of the light emitting device 1000B according to this embodiment is improved. Furthermore, by providing the glass substrate 1110B, the rigidity of the light emitting device 1000B can be increased.

[0076] The above-described embodiments of the present invention may be combined as appropriate as long as they are not mutually inconsistent. Furthermore, even if a person skilled in the art appropriately adds or deletes components or modifies designs, or adds or omits processes or modifies conditions based on the embodiments, such combinations are included within the scope of the present invention as long as they include the gist of the present invention.

[0077] Even if there are other effects and advantages different from those brought about by the above-mentioned embodiments, if they are clear from the description in this specification or can be easily predicted by a person skilled in the art, they are naturally understood to be brought about by the present invention.

[0078] 1000, 1000A, 1000B: light emitting device, 1010: supporting substrate, 1010_1: first surface, 1010_2: second surface, 1011, 1012: substrate, 1011_1: first surface, 1011_2: second surface, 1013: notch, 1020: degassing prevention layer, 1030: undoped nitride semiconductor layer, 1040: n-type nitride semiconductor layer, 1041: recess, 1050: light emitting layer, 1051: well layer, 1052: barrier layer, 1060: p-type nitride semiconductor layer, 1070: protective layer, 1071: first opening, 1072: second opening, 1080: n-type electrode, 1090: p-type electrode 1100A: Optical adjustment layer, 1110B: Glass substrate, 1120B: Adhesive layer

Claims

1. A ScAlMgO alloy having a first surface and a second surface opposite the first surface. ４ A substrate and the ScAlMgO ４ an undoped nitride semiconductor layer on the second surface of the substrate; and a light emitting layer on the undoped nitride semiconductor layer, the light emitting layer comprising In ｘ G （１－ｘ） A well layer containing N (0.30≦x≦0.50) and In ｙ G （１－ｙ） a barrier layer containing N (0<y<x) and a MQW structure in which the barrier layer containing N and the barrier layer containing N are alternately stacked, and a concave-convex pattern is provided on the side of the first surface.

2. The undoped nitride semiconductor layer is made of ScAlMgO ４ The light emitting device of claim 1 in contact with the second surface of the substrate.

3. The light emitting device according to claim 1, wherein the height of the projections and recesses in the projection and recess pattern is 1 μm or more and 3 μm or less.

4. The ScAlMgO ４ The light emitting device according to claim 1 , wherein the thickness of the substrate is not less than 5 μm and not more than 10 μm.

5. The uneven pattern is made of ScAlMgO ４ The light emitting device of claim 1 formed on the first surface of a substrate.

6. Furthermore, the ScAlMgO ４ an optical adjustment layer on the first surface of the substrate, the refractive index of the optical adjustment layer being selected from the group consisting of ScAlMgO ４ The light emitting device according to claim 1 , wherein the refractive index is smaller than that of the substrate, and the concave-convex pattern is formed on the optical adjustment layer.

7. Furthermore, the ScAlMgO ４ The light emitting device according to claim 1 , further comprising a glass substrate bonded to the first surface of the substrate, the concave-convex pattern being formed on the glass substrate.

8. ScAlMgO ４ forming a degassing prevention layer on the first surface of the support substrate; ４ forming an undoped nitride semiconductor layer on a second surface of a support substrate opposite to the first surface; and depositing In on the undoped nitride semiconductor layer by sputtering. ｘ G （１－ｘ） A well layer containing N (0.30≦x≦0.50) and In ｙ G （１－ｙ） and forming a barrier layer containing N (0<y<x) alternately to form a light emitting layer having an MQW structure.

9. The method for producing a light emitting device according to claim 8, wherein the undoped nitride semiconductor layer is formed by sputtering.

10. Furthermore, the ScAlMgO ４ The method for manufacturing a light emitting device according to claim 8 , further comprising: cleaving the support substrate to remove the degassing prevention layer.

11. Furthermore, the ScAlMgO ４ The method for manufacturing a light emitting device according to claim 10, further comprising forming a concave-convex pattern on a third surface exposed by cleaving the support substrate.

12. Furthermore, the ScAlMgO ４ forming an optical adjustment layer on a third surface that is revealed by cleaving the support substrate, the refractive index of the optical adjustment layer being determined by the refractive index of the ScAlMgO ４ The method for manufacturing a light emitting device according to claim 10 , wherein the refractive index is smaller than that of the substrate.

13. The method for manufacturing a light emitting device according to claim 12, further comprising forming a concave-convex pattern on the optical adjustment layer.

14. Furthermore, the ScAlMgO ４ The method for manufacturing a light emitting device according to claim 10, further comprising: bonding a glass substrate to the third surface exposed by cleaving the support substrate.

15. The method for manufacturing a light emitting device according to claim 14, wherein the glass substrate before being bonded to the third surface includes a concave-convex pattern.

16. The ScAlMgO ４ The cleavage of the support substrate is performed by ４ A notch is formed on an end surface of the support substrate, and the ScAlMgO ４ The method for manufacturing a light emitting device according to claim 10, further comprising applying a compressive pressure to the end surface of the support substrate.

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