Light-emitting device

Abstract

To provide a light-emitting device capable of reducing a decrease in light reflectance of a wiring.SOLUTION: A light-emitting device 100 includes: an n-side semiconductor layer 14; an active layer 16; and a p-side semiconductor layer 18, and includes: a first opening 12A exposing the n-side semiconductor layer from the active layer and the p-side semiconductor layer; a first insulating film 30 having a second opening at a position overlapping the first opening in a plan view; a first metal layer 21 in contact with the n-side semiconductor layer in the second opening; a second metal layer 22 disposed thereon; and a third metal layer 23 disposed thereon. A light reflectance of the first metal layer with respect to a peak wavelength of light emitted from the active layer is higher than a light reflectance of the third metal layer. The first metal layer has the same crystal structure as a crystal structure of the third metal layer, the second metal layer has a crystal structure different from the crystal structure of the first metal layer and the crystal structure of the third metal layer. The third metal layer does not overlap with the first opening in the plan view.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to light-emitting devices. [Background technology]

[0002] Patent Document 1 discloses a light emitting device in which an opening is provided in a semiconductor layer of a semiconductor structure, and wiring is brought into contact with the semiconductor layer exposed through the opening. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-63468 Summary of the Invention [Problem to be solved by the invention]

[0004] When the wiring of a light emitting element includes a plurality of metal layers, the light reflectance of the wiring may decrease at an opening in the semiconductor structure.

[0005] An object of the present disclosure is to provide a light-emitting element that can reduce a decrease in the light reflectance of wiring of the light-emitting element. [Means for solving the problem]

[0006] According to an embodiment of the present disclosure, a light-emitting element includes an n-side semiconductor layer, an active layer disposed on the n-side semiconductor layer, and a p-side semiconductor layer disposed on the active layer, the light-emitting element including a semiconductor structure having a first opening provided in the active layer and the p-side semiconductor layer to expose the n-side semiconductor layer from the active layer and the p-side semiconductor layer, a first insulating film disposed on the semiconductor structure and having a second opening at a position overlapping the first opening in a plan view, a first metal layer in contact with the n-side semiconductor layer in the second opening, and a metal layer disposed on the first metal layer. and an n-side interconnection including a second metal layer disposed on the first metal layer and a third metal layer disposed on the second metal layer, wherein the optical reflectance of the first metal layer for a peak wavelength of light emitted by the active layer is higher than the optical reflectance of the third metal layer for the peak wavelength of light emitted by the active layer, the first metal layer has the same crystal structure as the third metal layer, the second metal layer has a crystal structure different from the crystal structure of the first metal layer and the crystal structure of the third metal layer, and the third metal layer does not overlap the first opening in a planar view.

[0007] According to an embodiment of the present disclosure, there is provided a light-emitting device comprising: an n-side semiconductor layer; an active layer disposed on the n-side semiconductor layer; and a p-side semiconductor layer disposed on the active layer, the semiconductor structure having a first opening provided in the active layer and the p-side semiconductor layer to expose the n-side semiconductor layer from the active layer and the p-side semiconductor layer; a first insulating film disposed on the semiconductor structure and having a second opening at a position overlapping with the first opening in a planar view; and n-side wiring comprising: a first metal layer in contact with the n-side semiconductor layer in the second opening, a second metal layer disposed on the first metal layer, and a third metal layer disposed on the second metal layer, wherein the first metal layer contains a metal element selected from at least one of Al and Ag, the second metal layer contains a metal element selected from at least one of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re, and the third metal layer contains a metal element selected from at least one of Au and Cu, and the third metal layer does not overlap with the first opening in a planar view. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to reduce the decrease in light reflectance of wiring of a light-emitting element. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view of a light-emitting element according to a first embodiment. [Figure 2] 2 is a cross-sectional view taken along the line AA in FIG. 1. [Figure 3] 2 is a cross-sectional view of FIG. 1 taken along line B-B. [Figure 4] 2 is a cross-sectional view taken along CC in FIG. 1. [Figure 5] 3 is an enlarged plan view of a first opening 12A and a second opening 30A in the first embodiment. FIG. [Figure 6] 3 is an enlarged cross-sectional view of a first opening 12A and a second opening 30A in the first embodiment. FIG. [Figure 7] 10 is an enlarged cross-sectional view of a first opening 12A and a second opening 30A in a comparative structure. FIG. [Figure 8] 10 is an enlarged plan view of a peripheral region 12B and a fourth opening 30B in the first embodiment. FIG. [Figure 9] FIG. 3 is an enlarged cross-sectional view of a third opening 34A in the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments for carrying out the present disclosure will be described in detail with reference to the drawings. The following embodiments are examples for embodying the technical ideas of the invention, and the present disclosure is not limited to the described configurations and numerical values. In each drawing, the same components are given the same reference numerals, and duplicate explanations may be omitted as appropriate. The size, positional relationship, etc. of each component shown in each drawing may be exaggerated to facilitate understanding of the invention.

[0011] (First embodiment) FIG. 1 is a plan view of a light-emitting element according to a first embodiment. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, FIG. 3 is a cross-sectional view taken along line BB in FIG. 1, and FIG. 4 is a cross-sectional view taken along line CC in FIG. 1. FIG. 1 illustrates a substrate 10, a semiconductor structure 12, a wiring 20, an n-side electrode 29N, a p-side electrode 29P, an opening 20B, a second opening 30A, a fourth opening 30B, and an opening 32A. The thickness direction of the substrate 10 is defined as the Z direction, the extension direction of the p-side wiring 20P is defined as the X direction, and the direction perpendicular to the X and Z directions is defined as the Y direction. The viewpoint seen from the Z direction is also referred to as a planar view.

[0012] As shown in FIG. 1, in the light-emitting device 100 of the first embodiment, a semiconductor structure 12 is disposed on a substrate 10. An n-side wiring 20N and a p-side wiring 20P are disposed on the semiconductor structure 12 as wirings 20. The n-side wiring 20N has a protruding portion 20C whose outer edge protrudes outward in a plan view. In the example shown in FIG. 1, the planar shape of the protruding portion 20C is approximately semicircular. An opening 20B is provided in the n-side wiring 20N. In the example shown in FIG. 1, the planar shape of the opening 20B is approximately rectangular with the X direction longer than the Y direction. In a planar view, a p-side wiring 20P is disposed within the opening 20B. The n-side wiring 20N and the p-side wiring 20P are electrically isolated from each other. In the example shown in FIG. 1, the planar shape of the p-side wiring 20P is approximately rectangular with the X direction longer than the Y direction.

[0013] In a plan view, the first opening 12A of the semiconductor structure 12, the second opening 30A of the first insulating film 30, and the fourth opening 30B of the first insulating film 30 are arranged so as to overlap with the n-side wiring 20N. The first insulating film 30 and the semiconductor structure 12 will be described later. In a plan view, the first opening 12A and the second opening 30A are arranged more inward than the peripheral region 12B described later. In a plan view, the fourth opening 30B is arranged so as to overlap with the protruding portion 20C of the n-side wiring 20N. In a plan view, the second opening 30A is arranged so as to overlap with the first opening 12A. The first opening 12A, the second opening 30A, and the fourth opening 30B have, for example, a circular planar shape. A third opening 34A is provided so as to overlap with the p-side wiring 20P in a planar view. For example, the planar shape of the third opening 34A is a substantially rectangular shape with the X direction longer than the Y direction.

[0014] 1 and 3, an n-side electrode 29N may be disposed on an n-side wiring 20N. Also, a p-side electrode 29P may be disposed on a p-side wiring 20P. For example, the planar shapes of the n-side electrode 29N and the p-side electrode 29P are elliptical or circular. The planar shapes of the n-side wiring 20N, the p-side wiring 20P, the opening 20B, the protrusion 20C, the second opening 30A, the fourth opening 30B, the third opening 34A, the n-side electrode 29N, and the p-side electrode 29P may be other than those described above, as appropriate.

[0015] As shown in FIGS. 2 to 4, a semiconductor structure 12 is provided on a substrate 10. The substrate 10 is, for example, a sapphire substrate, a spinel substrate, a GaN (gallium nitride) substrate, a SiC (silicon carbide) substrate, a ZnS (zinc sulfide) substrate, a ZnO (zinc oxide) substrate, a GaAs (gallium arsenide) substrate, or a Si (silicon) substrate. The planar shape of the substrate 10 is, for example, rectangular. When the planar shape of the substrate 10 is rectangular, the length of one side is, for example, 100 μm or more and 2000 μm or less. Each layer of the semiconductor structure 12 is, for example, a nitride semiconductor layer. The nitride semiconductor layer is, for example, In x Al y Ga 1-x-y N(0≦x≦1, 0≦y≦1, x+y≦1).

[0016] The semiconductor structure 12 includes an n-side semiconductor layer 14, an active layer 16, and a p-side semiconductor layer 18. The n-side semiconductor layer 14 is disposed on a substrate 10. The active layer 16 is disposed on the n-side semiconductor layer 14. The p-side semiconductor layer 18 is disposed on the active layer 16. The n-side semiconductor layer 14 is an n-type semiconductor layer containing n-type impurities. The p-side semiconductor layer 18 is a p-type semiconductor layer containing p-type impurities. The active layer 16 has, for example, an MQW (Multi Quantum Well) structure in which a plurality of barrier layers and a plurality of well layers are alternately stacked.

[0017] 2, the semiconductor structure 12 has a first opening 12A and a peripheral region 12B. The first opening 12A is provided in the active layer 16 and the p-side semiconductor layer 18, and exposes the n-side semiconductor layer 14 from the active layer 16 and the p-side semiconductor layer 18. The first opening 12A is surrounded by the active layer 16 and the p-side semiconductor layer 18 in a planar view. The peripheral region 12B is disposed on the periphery of the semiconductor structure 12, and is a region where the n-side semiconductor layer 14 is exposed from the active layer 16 and the p-side semiconductor layer 18. The peripheral region 12B surrounds the active layer 16 and the p-side semiconductor layer 18 in a planar view.

[0018] 2 to 4, a first conductor layer 36 is disposed on the p-side semiconductor layer 18. The first conductor layer 36 is electrically connected to the p-side semiconductor layer 18. A first layer 32 is provided on the first conductor layer 36. The first layer 32 has an opening 32A that overlaps the first conductor layer 36 in a plan view. A second conductor layer 38 is disposed on the first layer 32. The second conductor layer 38 is electrically connected to the first conductor layer 36 through the opening 32A. A second layer 34 is provided on the second conductor layer 38. As shown in FIG. 4, the second layer 34 has a third opening 34A.

[0019] The wiring 20 is disposed on the second layer 34. In this embodiment, the second layer may also be referred to as a second insulating film. The wiring 20 includes an n-side wiring 20N and a p-side wiring 20P. As shown in FIG. 4, the wiring 20 has an opening 20A, which electrically separates the n-side wiring 20N from the p-side wiring 20P. The p-side wiring 20P is electrically connected to the second conductor layer 38 through a third opening 34A. As shown in FIGS. 3 and 4, an n-side electrode 29N is disposed on the n-side wiring 20N, and a p-side electrode 29P is disposed on the p-side wiring 20P. The n-side electrode 29N is electrically connected to the n-side wiring 20N, and the p-side electrode 29P is electrically connected to the p-side wiring 20P.

[0020] 2, the first layer 32 and the second layer 34 cover the side surfaces of the semiconductor structure 12 in the first opening 12A and the peripheral region 12B. In this embodiment, the first insulating film 30 has the first layer 32 and the second layer 34. The first insulating film 30 has a second opening 30A at a position overlapping the first opening 12A in a plan view, and a fourth opening 30B at a position overlapping the peripheral region 12B in a plan view. The n-side wiring 20N is electrically connected to the n-side semiconductor layer 14 via the first opening 12A and the second opening 30A.

[0021] As a result, the n-side electrode 29N is electrically connected to the n-side semiconductor layer 14 via the n-side wiring 20N. The p-side electrode 29P is electrically connected to the p-side semiconductor layer 18 via the p-side wiring 20P, the second conductive layer 38, and the first conductive layer 36.

[0022] The first layer 32 is a film primarily composed of, for example, silicon oxide or silicon nitride, and may be a single-layer film or a laminate of multiple insulating films. The first layer 32 may have the function of reflecting light emitted by the active layer 16. If the first layer 32 has the function of reflecting light emitted by the active layer 16, the optical reflectance of the first layer 32 for the peak wavelength of light emitted by the active layer 16 is preferably 80% or more. The first conductive layer 36 is a transparent conductor such as ITO (indium tin oxide), ZnO (zinc oxide), or In2O3 (indium oxide). The first conductive layer 36 diffuses current in the planar direction and reduces bias in light distribution.

[0023] The second layer 34 is, for example, a silicon oxide film or a silicon nitride film, and may be a single layer film or a laminate of multiple insulating films. The second conductive layer 38 is, for example, a metal layer containing silver or aluminum as a main component. The configuration of the wiring 20 will be described later. The n-side electrode 29N and the p-side electrode 29P are metal layers containing Au (gold), Ag (silver), Cu (copper), Al (aluminum), Pt (platinum), or an alloy thereof as a main component.

[0024] FIG. 5 is an enlarged plan view of the first opening 12A and the second opening 30A in the first embodiment. FIG. 6 is an enlarged cross-sectional view of the first opening 12A and the second opening 30A in the first embodiment, taken along the line AA in FIG. 5. As shown in FIG. 6, the first opening 12A is defined by a first surface 13A of the semiconductor structure 12 and a second surface 13B of the semiconductor structure 12. The first surface 13A is a portion of the surface of the n-side semiconductor layer 14. The second surface 13B is a portion of the side surface of the n-side semiconductor layer 14, a portion of the side surface of the active layer 16, and a portion of the side surface of the p-side semiconductor layer 18, and is connected to the first surface 13A. The inclination angle of the second surface 13B with respect to the first surface 13A is θ1. The second opening 30A is defined by a portion of the side surface of the first insulating film 30. In this embodiment, as shown in FIGS. 5 and 6, the n-side wiring 20N includes a first metal layer 21, a second metal layer 22, and a third metal layer 23. The n-side wiring 20N may further include a fourth metal layer 24. The first metal layer 21 is disposed on the first insulating film 30 and the n-side semiconductor layer 14, and is electrically connected to the n-side semiconductor layer 14. The second metal layer 22 is disposed on the first metal layer 21. The fourth metal layer 24 is disposed on the second metal layer 22. The third metal layer 23 is disposed on the fourth metal layer 24. The third metal layer 23 is not disposed in the first opening 12A.

[0025] In this embodiment, the lower end 51 (end in the -Z direction) of the side surface of the third metal layer 23, the upper end 52 (end in the +Z direction) of the second surface 13B, the lower end 53 of the second surface 13B, the upper end 54 of the side surface of the first insulating film 30 that defines the second opening 30A, and the lower end 55 of the side surface of the first insulating film 30 that defines the second opening 30A are arranged concentrically. The planar shapes of the lower end 51 of the side surface of the third metal layer 23, the upper end 52 of the second surface 13B, the lower end 53 of the second surface 13B, the upper end 54 of the side surface of the first insulating film 30 that defines the second opening 30A, and the lower end 55 of the side surface of the first insulating film 30 that defines the second opening 30A may be elliptical or polygonal other than circular, and can be set as appropriate.

[0026] The inclination angle of the side surface of the first insulating film 30 with respect to the first surface 13A is θ2. The distance in the Z direction between the first surface 13A and the surface of the p-side semiconductor layer 18 is T1. The thickness of the first insulating film 30 within the first opening 12A is T2. The thickness of the second metal layer 22 outside the first opening 12A is T3. The distance of the third metal layer 23 from the first opening 12A is L1.

[0027] The first metal layer 21 is a layer that is electrically connected to the n-side semiconductor layer 14, and has the function of reflecting light emitted from the active layer 16. As will be described later, the third metal layer 23 is a layer with low electrical resistance, and diffuses current in the planar direction.

[0028] During heat treatment in the manufacturing process of the light-emitting device, interdiffusion may occur between the metal elements of the first metal layer 21 and the metal elements of the third metal layer 23. When interdiffusion occurs, the light reflectance of the first metal layer 21 decreases. Furthermore, the resistivity of the third metal layer 23 increases. By providing the second metal layer 22, it is possible to reduce interdiffusion between the first metal layer 21 and the third metal layer 23. It is preferable to provide a fourth metal layer 24 between the second metal layer 22 and the third metal layer 23, which has the function of reducing corrosion of the second metal layer 22 and the third metal layer 23. The fourth metal layer 24 is not necessarily provided.

[0029] The optical reflectance of the first metal layer 21 for the peak wavelength emitted by the active layer 16 is higher than the reflectance of the third metal layer 23 for the peak wavelength emitted by the active layer 16. As a result, the first metal layer 21 functions as a layer that reflects light.

[0030] Metals having the same crystal structure tend to easily interdiffuse. The first metal layer 21 has the same crystal structure as the third metal layer 23. Therefore, the metal of the third metal layer 23 is likely to diffuse into the first metal layer 21. This makes it easier for the light reflectance of the first metal layer 21 to decrease. Therefore, in the present disclosure, a second metal layer 22 having a crystal structure different from the crystal structures of the first metal layer 21 and the third metal layer 23 is disposed between the first metal layer 21 and the third metal layer 23. This reduces the interdiffusion of metals between the first metal layer 21 and the third metal layer 23.

[0031] (Comparison structure) FIG. 7 is an enlarged cross-sectional view of the first opening 12A and the second opening 30A in the comparative structure. As shown in FIG. 7, in the light-emitting element 110 of the comparative structure, a third metal layer 23 is provided on the fourth metal layer 24 in the first opening 12A. When a layer for reducing interdiffusion, such as the second metal layer 22, is formed, cracks 50 are likely to occur at the corners of the outer periphery of the first opening 12A. This is because, when the second metal layer 22 is formed, the second metal layer 22 is formed on the top surface 21A of the first metal layer 21 in a direction perpendicular to the top surface 21A, and the second metal layer 22 is formed on the side surface 21B of the first metal layer 21 in a direction perpendicular to the side surface 21B. Because the second metal layer 22 is formed in two directions at the contact point between the top surface 21A and the side surface 21B, gaps are likely to occur between them. Cracks 50 are particularly likely to occur when the second metal layer 22 is formed using a sputtering method. If cracks 50 occur, interdiffusion occurs between first metal layer 21 and third metal layer 23 through cracks 50. Similar cracks may also occur around the periphery of second opening 30A.

[0032] (Description of the First Embodiment) 5 and 6, in the first embodiment, the third metal layer 23 does not overlap the first opening 12A in plan view. This makes it possible to reduce interdiffusion between the first metal layer 21 and the third metal layer 23 even if a crack 50 occurs in the third metal layer 23. This makes it possible to reduce a decrease in the light reflectance of the first metal layer 21.

[0033] In order to increase the light reflectance of the first metal layer 21, the first metal layer 21 contains at least one of Al and Ag as a main component. As an example, the first metal layer 21 has a composition of 98 atomic % Al and also contains Si and Cu. Table 1 shows the crystal structures and melting points of exemplary metals used in the first metal layer 21.

[0034] [Table 1]

[0035] fcc indicates a face-centered cubic structure, hcp indicates a hexagonal close-packed structure, and bcc indicates a body-centered cubic structure.

[0036] The third metal layer 23 is mainly composed of a metal with low resistivity, such as at least one of Au and Cu. As an example, the third metal layer 23 is mainly composed of Au. For example, the optical reflectance for light having a wavelength of 400 nm or more and 500 nm or less is 80% or more, 90% or more, 70% or more, and 60% or more for Al, Ag, Au, and Cu, respectively.

[0037] Table 2 shows the crystal structures and melting points of exemplary metals used in the third metal layer 23.

[0038] [Table 2]

[0039] As shown in Tables 1 and 2, the crystal structures of Al, Ag, Au, and Cu are fcc. Thus, the crystal structure of the first metal layer 21 and the crystal structure of the third metal layer 23 are the same. Therefore, interdiffusion between the first metal layer 21 and the third metal layer 23 is likely to occur. Therefore, a metal having a crystal structure other than fcc is used for the second metal layer 22. The second metal layer 22 contains at least one of Ti (titanium), Ta (tantalum), W (tungsten), Mo (molybdenum), Nb (niobium), Cr (chromium), Zr (zirconium), Hf (hafnium), and Re (rhenium) as a main component.

[0040] Table 3 shows the crystal structures and melting points of exemplary metals used in the second metal layer 22.

[0041] [Table 3]

[0042] As shown in Table 3, the crystal structures of Ti, Zr, Hf, and Re are hcp. The crystal structures of Ta, W, Mo, Nb, and Cr are bcc. Thus, the crystal structures of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re are different from the crystal structures of Al, Ag, Au, and Cu. In order to reduce interdiffusion between the first metal layer 21 and the third metal layer 23, it is preferable that the second metal layer 22 have a close-packed crystal structure. From this perspective, it is preferable that the crystal structure of the second metal layer 22 be a close-packed hexagonal lattice structure.

[0043] To enhance the function of the second metal layer 22 in reducing interdiffusion between the first metal layer 21 and the third metal layer 23, the melting point of the second metal layer 22 is preferably higher than the melting points of the first metal layer 21 and the third metal layer 23. As shown in Tables 1 to 3, the melting point of the second metal layer 22 is higher than the melting points of the first metal layer 21 and the third metal layer 23. For example, the melting point of the second metal layer 22 is preferably 500°C or more higher than the melting points of the first metal layer 21 and the third metal layer 23. On the other hand, when a metal layer with a high melting point is formed, it is likely to have a columnar structure and cracks are likely to occur. Therefore, it is more preferable to arrange the third metal layer 23 so that it does not overlap the first opening 12A.

[0044] When metals with large differences in natural potential come into contact with each other, corrosion of the metals is likely to occur. For example, when the difference between the natural potentials of the second metal layer 22 and the third metal layer 23 is large, the second metal layer 22 and the third metal layer 23 are likely to corrode. Therefore, it is preferable to dispose a fourth metal layer 24, whose natural potential is between the natural potentials of the second metal layer 22 and the third metal layer 23, between the second metal layer 22 and the third metal layer 23. This makes it possible to make the difference between the natural potential of the second metal layer 22 and the fourth metal layer 24, and the difference between the natural potential of the fourth metal layer 24 and the third metal layer 23, smaller than the difference between the natural potential of the second metal layer 22 and the third metal layer 23. This reduces corrosion of the second metal layer 22 and the third metal layer 23.

[0045] The fourth metal layer 24 is mainly composed of at least one of Pt, Ru (ruthenium), and Rh (rhodium). For example, the natural potential of Pt is between the natural potentials of Au and Al. The order of the natural potentials of the metal elements is the same as the order of the ionization tendencies and the order of the standard electrode potentials of the metal elements.

[0046] Table 4 shows the crystal structures and melting points of exemplary metals used in the fourth metal layer 24.

[0047] [Table 4]

[0048] The term "a metal layer mainly contains a certain metal element" means that other elements may be contained to the extent that the metal layer functions. For example, the concentration of the metal element in the metal layer is 70 atomic % or more, preferably 85 atomic % or more.

[0049] Cracks 50 are likely to occur when the inclination angle θ1 is large and the thickness T3 of the second metal layer 22 is small. Therefore, when the inclination angle θ1 is 30° or greater and the thickness T3 is smaller than the distance T1, it is preferable to provide the third metal layer 23 so that it does not overlap the first opening 12A in a planar view. Cracks 50 are more likely to occur when the inclination angle θ1 is 40° or greater, and cracks 50 are even more likely to form when the inclination angle θ1 is 45° or greater. Therefore, in these cases, it is preferable to provide the third metal layer 23 so that it does not overlap the first opening 12A in a planar view. If the inclination angle θ1 is too large, the n-side wiring 20N is more likely to break. From this perspective, the inclination angle θ1 is preferably 90° or less, more preferably 80° or less, and even more preferably 50° or less.

[0050] When thickness T3 is 0.8 times or less the distance T1, cracks 50 are more likely to occur, and when it is 0.5 times or less, cracks 50 are even more likely to occur. Therefore, in these cases, it is preferable to provide third metal layer 23 so that it does not overlap first opening 12A in a planar view. From the viewpoint of exerting the function of reducing interdiffusion of second metal layer 22, thickness T3 is preferably 0.1 times or more the distance T1, and more preferably 0.2 times or more. Distance T1 is, for example, 500 nm or more and 3000 nm or less, or 1000 nm or more and 2000 nm or less. Thickness T3 is, for example, 100 nm or more and 1000 nm or less, or 200 nm or more and 500 nm or less.

[0051] When the thickness T2 of the first insulating film 30 is smaller than the thickness T3 of the second metal layer 22, cracks are unlikely to occur in the second metal layer 22 near the upper end 54 of the side surface of the first insulating film 30 that defines the second opening 30A. When the thickness T2 is larger than the thickness T3 and the inclination angle θ2 is 30° or greater, cracks are likely to occur in the second metal layer 22 near the upper end 54 of the side surface of the first insulating film 30 that defines the second opening 30A. In this case as well, by not overlapping the third metal layer 23 with the first opening 12A in plan view, a decrease in the light reflectance of the n-side wiring 20N can be reduced.

[0052] If the distance L1 from the first opening 12A of the third metal layer 23 is small, there is a possibility that the first metal layer 21 and the third metal layer 23 may interdiffuse through the cracks 50. From this viewpoint, the distance L1 is preferably 2 μm or more, and more preferably 5 μm or more. If the distance L1 is too large, the area in which the third metal layer 23 is disposed will be reduced, resulting in an increase in the wiring resistance of the n-side wiring 20N. From this viewpoint, the distance L1 is preferably 20 μm or less, and more preferably 10 μm or less.

[0053] 8 is an enlarged plan view of the periphery region 12B and the fourth opening 30B in the first embodiment. In this embodiment, as shown in FIG. 8, the third metal layer 23 of the n-side wiring 20N does not overlap with the periphery region 12B in plan view. By doing so, as described above, it is possible to reduce the decrease in reflectance of the n-side wiring 20N.

[0054] FIG. 9 is an enlarged cross-sectional view of the third opening 34A in the first embodiment. In this embodiment, as shown in FIG. 9, the second conductor layer 38 is disposed on the semiconductor structure 12 and is electrically connected to the p-side semiconductor layer 18 via the first conductor layer 36 (see FIG. 4). The second insulating film 34 is disposed on the second conductor layer 38 and has a third opening 34A exposing the second conductor layer 38. In this embodiment, the second insulating film is formed in the same process as the second layer, and therefore is denoted by the same reference numeral. The p-side wiring 20P contacts the second conductor layer 38 in the third opening 34A and includes a fifth metal layer 25, a sixth metal layer 26, and a seventh metal layer 27. An eighth metal layer 28 may be disposed between the sixth metal layer 26 and the seventh metal layer 27. The seventh metal layer 27 does not overlap the third opening 34A in a plan view. The fifth metal layer 25 is the same metal layer as the first metal layer 21. The sixth metal layer 26 is the same metal layer as the second metal layer 22. The seventh metal layer 27 is the same metal layer as the third metal layer 23. The eighth metal layer 28 is the same metal layer as the fourth metal layer 24. This allows the p-side interconnect 20P to achieve the same effect as the n-side interconnect 20N.

[0055] The thickness of the second insulating film 34 is T4, and the inclination angle of the side surface of the second layer 34 relative to the surface of the second conductor layer 38 is θ3. Cracks 50 are likely to occur when the inclination angle θ3 is large and the thickness T5 of the sixth metal layer 26 is small. Therefore, when the inclination angle θ3 is 30° or greater and the thickness T5 is smaller than the thickness T4, it is preferable to provide the seventh metal layer 27 so that it does not overlap the third opening 34A. The distance L2 of the seventh metal layer 27 from the third opening 34A is preferably 2 μm or greater.

[0056] The first metal layer 21 contains a metal element selected from at least one of Al and Ag. The content of the metal elements in the first metal layer 21 is preferably such that the metal element selected from at least one of Al and Ag is the largest. For example, the content of the metal elements in the first metal layer 21 is preferably such that the metal element selected from at least one of Al and Ag is 95 atomic % or more, more preferably 98 atomic % or more. The second metal layer 22 contains a metal element selected from at least one of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re. The content of the metal elements in the second metal layer 22 is preferably such that the metal element selected from at least one of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re is the largest. For example, the content of the metal elements in the second metal layer 22 is preferably such that the metal element selected from at least one of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re is 95 atomic % or more, more preferably 98 atomic % or more. The third metal layer 23 contains a metal element selected from at least one of Au and Cu. The content ratio of the metal elements in the third metal layer 23 is preferably such that the metal element selected from at least one of Au and Cu is the largest. For example, the content ratio of the metal elements in the third metal layer 23 is preferably such that the metal element selected from at least one of Au and Cu is 95 atomic % or more, and more preferably 98 atomic % or more. The fourth metal layer 24 contains a metal element selected from at least one of Pt, Ru, and Rh. The content ratio of the metal elements in the fourth metal layer 24 is preferably such that the metal element selected from at least one of Pt, Ru, and Rh is the largest. For example, the content ratio of the metal elements in the fourth metal layer 24 is preferably such that the metal element selected from at least one of Pt, Ru, and Rh is 95 atomic % or more, and more preferably 98 atomic % or more. The content ratio of a certain metal element to the metal elements contained in the metal layer is the ratio of the concentration of the certain metal element in the metal layer to the total concentration of detectable metal elements contained in the metal layer, expressed in atomic %. Note that the first metal layer 21, the second metal layer 22, the third metal layer 23, and the fourth metal layer 24 may contain elements other than metal elements (e.g., O (oxygen), N (nitrogen), and C (carbon)).

[0057] The above describes in detail preferred embodiments, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0058] The light-emitting device according to the embodiment of the present disclosure includes, for example, the following aspects. (Section 1) a semiconductor structure including an n-side semiconductor layer, an active layer disposed on the n-side semiconductor layer, and a p-side semiconductor layer disposed on the active layer, the semiconductor structure having a first opening provided in the active layer and the p-side semiconductor layer to expose the n-side semiconductor layer from the active layer and the p-side semiconductor layer; a first insulating film disposed on the semiconductor structure and having a second opening at a position overlapping the first opening in a plan view; an n-side interconnection including a first metal layer in contact with the n-side semiconductor layer in the second opening, a second metal layer disposed on the first metal layer, and a third metal layer disposed on the second metal layer; Equipped with the optical reflectance of the first metal layer at a peak wavelength of light emitted by the active layer is higher than the optical reflectance of the third metal layer at a peak wavelength of light emitted by the active layer; the first metal layer has the same crystal structure as the third metal layer; the second metal layer has a crystal structure different from a crystal structure of the first metal layer and a crystal structure of the third metal layer; The third metal layer does not overlap the first opening in a plan view. (Section 2) Item 2. The light-emitting device according to item 1, wherein the melting point of the second metal layer is higher than the melting point of the first metal layer and the melting point of the third metal layer. (Section 3) Item 3. The light-emitting device according to item 1 or 2, wherein the second metal layer has a hexagonal close-packed lattice structure. (Section 4) 4. The light-emitting device according to any one of items 1 to 3, wherein the second metal layer is mainly composed of at least one of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re. (Section 5) 5. The light-emitting device according to any one of items 1 to 4, wherein the first metal layer contains at least one of Al and Ag as a main component. (Section 6) Item 6. The light-emitting device according to any one of items 1 to 5, wherein the third metal layer contains at least one of Au and Cu as a main component. (Section 7) a first surface and a second surface of the semiconductor structure that define the first opening, the first surface being a part of a surface of the n-side semiconductor layer, and a second surface that is a part of a side surface of the n-side semiconductor layer, a part of a side surface of the active layer, and a part of a side surface of the p-side semiconductor layer and intersects with the first surface; the inclination angle of the second surface relative to the first surface is 30° or more; 7. The light-emitting device according to any one of items 1 to 6, wherein the thickness of the second metal layer is smaller than the distance between the first surface and the surface of the p-side semiconductor layer. (Section 8) Item 8. The light-emitting device according to any one of items 1 to 7, wherein the third metal layer is spaced 2 μm or more from the first opening in a plan view. (Section 9) the n-side interconnect includes a fourth metal layer disposed between the second metal layer and the third metal layer, Item 9. The light-emitting device according to any one of items 1 to 8, wherein the natural potential of the fourth metal layer is between the natural potential of the second metal layer and the natural potential of the third metal layer. (Section 10) the n-side interconnect includes a fourth metal layer disposed between the second metal layer and the third metal layer, Item 9. The light-emitting device according to any one of items 1 to 8, wherein the fourth metal layer contains at least one of Pt, Ru, and Rh as a main component. (Section 11) a conductive layer disposed on the semiconductor structure and electrically connected to the p-side semiconductor layer; a second insulating film disposed on the conductive layer and having a third opening exposing the conductive layer; a p-side interconnection in contact with the conductive layer in the third opening, the p-side interconnection including a fifth metal layer, a sixth metal layer disposed on the fifth metal layer, and a seventh metal layer disposed on the sixth metal layer; Equipped with the optical reflectance of the fifth metal layer at a peak wavelength of light emitted by the active layer is higher than the optical reflectance of the seventh metal layer at a peak wavelength of light emitted by the active layer; the fifth metal layer has the same crystal structure as the seventh metal layer; the sixth metal layer has a crystal structure different from the crystal structure of the fifth metal layer and the crystal structure of the seventh metal layer; Item 11. The light-emitting device according to any one of items 1 to 10, wherein the seventh metal layer does not overlap the third opening in plan view. (Section 12) a semiconductor structure including an n-side semiconductor layer, an active layer disposed on the n-side semiconductor layer, and a p-side semiconductor layer disposed on the active layer, the semiconductor structure having a first opening provided in the active layer and the p-side semiconductor layer to expose the n-side semiconductor layer from the active layer and the p-side semiconductor layer; a first insulating film disposed on the semiconductor structure and having a second opening at a position overlapping the first opening in a plan view; an n-side interconnection including a first metal layer in contact with the n-side semiconductor layer in the second opening, a second metal layer disposed on the first metal layer, and a third metal layer disposed on the second metal layer; Equipped with the first metal layer contains a metal element selected from at least one of Al and Ag; the second metal layer contains a metal element selected from at least one of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re; the third metal layer contains a metal element selected from at least one of Au and Cu, The third metal layer does not overlap the first opening in a plan view. (Section 13) the first metal layer contains a metal element selected from at least one of Al and Ag at a highest content ratio; The content ratio of the metal element in the second metal layer is highest when the metal element is selected from at least one of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re; Item 13. The light-emitting device according to item 12, wherein the content ratio of the metal elements in the third metal layer is the highest for a metal element selected from at least one of Au and Cu. (Section 14) The content ratio of the metal element in the first metal layer is such that the metal element selected from at least one of Al and Ag is 95 atomic % or more, The content ratio of the metal element in the second metal layer is 95 atomic % or more of a metal element selected from at least one of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re; Item 14. The light-emitting device according to item 12 or 13, wherein the third metal layer contains 95 atomic % or more of a metal element selected from at least one of Au and Cu. (Section 15) the first metal layer has the same crystal structure as the third metal layer; Item 15. The light-emitting device according to any one of items 12 to 14, wherein the second metal layer has a crystal structure different from a crystal structure of the first metal layer and a crystal structure of the third metal layer. (Section 16) Item 16. The light-emitting element according to any one of items 12 to 15, wherein the optical reflectance of the first metal layer at a peak wavelength of light emitted by the active layer is higher than the optical reflectance of the third metal layer at a peak wavelength of light emitted by the active layer. (Section 17) the n-side interconnect includes a fourth metal layer disposed between the second metal layer and the third metal layer, Item 17. The light-emitting device according to any one of items 12 to 16, wherein the fourth metal layer contains a metal element selected from at least one of Pt, Ru, and Rh. (Section 18) Item 18. The light-emitting device according to item 17, wherein the content ratio of the metal element in the fourth metal layer is highest when the metal element is at least one selected from Pt, Ru, and Rh. (Section 19) Item 19. The light-emitting device according to item 17 or 18, wherein the fourth metal layer contains 95 atomic % or more of a metal element selected from at least one of Pt, Ru, and Rh. (Section 20) the n-side interconnect includes a fourth metal layer disposed between the second metal layer and the third metal layer, Item 20. The light-emitting device according to any one of items 12 to 19, wherein the natural potential of the fourth metal layer is between the natural potential of the second metal layer and the natural potential of the third metal layer. [Explanation of symbols]

[0059] 10: Circuit board 12: Semiconductor structure 12A: 1st opening 12B: Outer area 13A: 1st page 13B:Second side 14: n-side semiconductor layer 16:Active layer 18: p-side semiconductor layer 20: Wiring 20B: Opening 20C:Protrusion 20N:n side wiring 20P:p side wiring 21: 1st metal layer 22: Second metal layer 23: Third metal layer 24: 4th metal layer 25: 5th metal layer 26: 6th metal layer 27: 7th metal layer 28: 8th metal layer 29N: n-side electrode 29P:p side electrode 30: First insulating film 30A: 2nd opening 30B: 4th opening 32: 1st layer 34:Second layer 34A: 3rd opening 36: First conductive layer 38: Second conductive layer

Claims

1. a semiconductor structure including an n-side semiconductor layer, an active layer disposed on the n-side semiconductor layer, and a p-side semiconductor layer disposed on the active layer, the semiconductor structure having a first opening provided in the active layer and the p-side semiconductor layer to expose the n-side semiconductor layer from the active layer and the p-side semiconductor layer; a first insulating film disposed on the semiconductor structure and having a second opening at a position overlapping the first opening in a plan view; an n-side interconnect including a first metal layer in contact with the n-side semiconductor layer in the second opening, a second metal layer disposed on the first metal layer, and a third metal layer disposed on the second metal layer; Equipped with an optical reflectance of the first metal layer at a peak wavelength of light emitted by the active layer is higher than an optical reflectance of the third metal layer at a peak wavelength of light emitted by the active layer; the first metal layer has the same crystal structure as the third metal layer; the second metal layer has a crystal structure different from a crystal structure of the first metal layer and a crystal structure of the third metal layer; The third metal layer does not overlap the first opening in a plan view.

2. The light emitting device according to claim 1 , wherein the melting point of the second metal layer is higher than the melting point of the first metal layer and the melting point of the third metal layer.

3. The light-emitting device according to claim 1 , wherein the second metal layer has a hexagonal close-packed lattice structure.

4. The light-emitting device according to claim 1 , wherein the second metal layer is mainly composed of at least one of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re.

5. The light-emitting element according to claim 4 , wherein the first metal layer is mainly composed of at least one of Al and Ag.

6. The light-emitting element according to claim 5 , wherein the third metal layer is mainly composed of at least one of Au and Cu.

7. a first surface and a second surface of the semiconductor structure that define the first opening, the first surface being a part of a surface of the n-side semiconductor layer, and a second surface that is a part of a side surface of the n-side semiconductor layer, a part of a side surface of the active layer, and a part of a side surface of the p-side semiconductor layer and intersects with the first surface; an inclination angle of the second surface relative to the first surface is 30° or more; The light-emitting element according to claim 1 , wherein the thickness of the second metal layer is smaller than the distance between the first surface and the surface of the p-side semiconductor layer.

8. The light-emitting element according to claim 1 , wherein the third metal layer is spaced from the first opening by 2 μm or more in a plan view.

9. the n-side interconnect includes a fourth metal layer disposed between the second metal layer and the third metal layer, The light-emitting element according to claim 1 , wherein the natural potential of the fourth metal layer is between the natural potential of the second metal layer and the natural potential of the third metal layer.

10. the n-side interconnect includes a fourth metal layer disposed between the second metal layer and the third metal layer, The light-emitting element according to claim 6 , wherein the fourth metal layer is mainly composed of at least one of Pt, Ru, and Rh.

11. a conductive layer disposed on the semiconductor structure and electrically connected to the p-side semiconductor layer; a second insulating film disposed on the conductive layer and having a third opening exposing the conductive layer; a p-side interconnection in contact with the conductive layer in the third opening, the p-side interconnection including a fifth metal layer, a sixth metal layer disposed on the fifth metal layer, and a seventh metal layer disposed on the sixth metal layer; Equipped with the optical reflectance of the fifth metal layer at a peak wavelength of light emitted by the active layer is higher than the optical reflectance of the seventh metal layer at a peak wavelength of light emitted by the active layer; the fifth metal layer has the same crystal structure as the seventh metal layer; the sixth metal layer has a crystal structure different from a crystal structure of the fifth metal layer and a crystal structure of the seventh metal layer; The light-emitting element according to claim 1 , wherein the seventh metal layer does not overlap the third opening in a plan view.

12. a semiconductor structure including an n-side semiconductor layer, an active layer disposed on the n-side semiconductor layer, and a p-side semiconductor layer disposed on the active layer, the semiconductor structure having a first opening provided in the active layer and the p-side semiconductor layer to expose the n-side semiconductor layer from the active layer and the p-side semiconductor layer; a first insulating film disposed on the semiconductor structure and having a second opening at a position overlapping the first opening in a plan view; an n-side interconnect including a first metal layer in contact with the n-side semiconductor layer in the second opening, a second metal layer disposed on the first metal layer, and a third metal layer disposed on the second metal layer; Equipped with the first metal layer contains a metal element selected from at least one of Al and Ag; the second metal layer contains a metal element selected from at least one of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re; the third metal layer contains a metal element selected from at least one of Au and Cu; The third metal layer does not overlap the first opening in a plan view.

13. the first metal layer contains a metal element selected from at least one of Al and Ag at a highest content ratio; The content ratio of the metal element in the second metal layer is highest when the metal element is at least one selected from Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re; The light-emitting element according to claim 12 , wherein a content ratio of the metal elements in the third metal layer is highest when the metal element is selected from at least one of Au and Cu.

14. a content ratio of a metal element selected from at least one of Al and Ag in the first metal layer is 95 atomic % or more; The content ratio of the metal element in the second metal layer is 95 atomic % or more of a metal element selected from at least one of Ti, Ta, W, Mo, Nb, Cr, Zr, Hf, and Re; 13. The light-emitting element according to claim 12, wherein the content of the metal element in the third metal layer is 95 atomic % or more of a metal element selected from at least one of Au and Cu.

15. the first metal layer has the same crystal structure as the third metal layer; The light-emitting element according to claim 12 , wherein the second metal layer has a crystal structure different from a crystal structure of the first metal layer and a crystal structure of the third metal layer.

16. 15. The light-emitting element according to claim 12, wherein the optical reflectivity of the first metal layer for the peak wavelength of light emitted by the active layer is higher than the optical reflectivity of the third metal layer for the peak wavelength of light emitted by the active layer.

17. the n-side interconnect includes a fourth metal layer disposed between the second metal layer and the third metal layer, The light-emitting element according to claim 12 , wherein the fourth metal layer contains a metal element selected from at least one of Pt, Ru, and Rh.

18. 18. The light-emitting element according to claim 17, wherein a content ratio of the metal element in the fourth metal layer is highest when the metal element is at least one of Pt, Ru, and Rh.

19. 18. The light-emitting element according to claim 17, wherein the fourth metal layer contains 95 atomic % or more of a metal element selected from at least one of Pt, Ru, and Rh.

20. the n-side interconnect includes a fourth metal layer disposed between the second metal layer and the third metal layer, The light-emitting element according to claim 12 , wherein the natural potential of the fourth metal layer is between the natural potential of the second metal layer and the natural potential of the third metal layer.

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