Light emitting element

Abstract

To provide a light emitting element having a large brightness difference between a central region and a peripheral region of a primary light extraction face.SOLUTION: A light emitting element includes: a semiconductor structure including a first semiconductor layer that has a first face and a second face located on the opposite side of the first face and having a first region and a second region, an active layer disposed on the first region, and a second semiconductor layer disposed on the active layer; a first electrode disposed on the second region and electrically connected to the first semiconductor layer; and a second electrode disposed on the second semiconductor layer and electrically connected to the second semiconductor layer. The first face has an outer peripheral region and a central region that is surrounded by the outer peripheral region in a plan view, a surface roughness of the central region being higher than a surface roughness of the outer peripheral region. A first reflecting film is disposed only on the outer peripheral region among the surfaces of the semiconductor structure, and a first protective film having a higher light transmittance for the peak wavelength of light emitted by the active layer than that of the first reflecting film is disposed on the central region.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a light-emitting device. [Background technology]

[0002] For example, Patent Document 1 discloses a light emitting device in which a concave-convex structure is formed on a first surface of a semiconductor layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-32809 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a light emitting element having a large difference in luminance between the central region and the peripheral region of the main light extraction surface. [Means for solving the problem]

[0005] According to one aspect of the present invention, a light-emitting element comprises a semiconductor structure having a first semiconductor layer having a first surface and a second surface located opposite the first surface and having a first region and a second region, an active layer arranged on the first region, and a second semiconductor layer arranged on the active layer, a first electrode arranged in the second region and electrically connected to the first semiconductor layer, and a second electrode arranged on the second semiconductor layer and electrically connected to the second semiconductor layer, wherein the first surface has a peripheral region and a central region surrounded by the peripheral region in a planar view and having a surface roughness greater than that of the peripheral region, a first reflective film is arranged only on the peripheral region of the surface of the semiconductor structure, and a first protective film having a higher transmittance for the peak wavelength of light emitted by the active layer than the first reflective film is arranged in the central region. Effect of the Invention

[0006] According to the present invention, it is possible to provide a light emitting element having a large difference in luminance between the central region and the peripheral region of the main light extraction surface. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic plan view of a light emitting element according to the embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. [Figure 3A] FIG. 2 is a schematic cross-sectional view of a first reflective film according to the embodiment. [Figure 3B] FIG. 4 is a schematic cross-sectional view of a second reflective film according to the embodiment. [Figure 4] 1 is a schematic cross-sectional view of a light emitting device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the embodiments will be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments are not intended to be limited thereto, and are merely illustrative examples, unless otherwise specified. The sizes and positional relationships of the components shown in each drawing may be exaggerated to clarify the explanation. In the following explanation, the same names and symbols indicate the same or similar components, and detailed explanations will be omitted as appropriate. In addition, as a cross-sectional view, an end view showing only a cut surface may be shown.

[0009] In the following description, terms indicating a specific direction or position (e.g., "upper", "lower", and other terms including these terms) may be used. However, these terms are merely used for the purpose of making the relative direction or position in the referenced drawings easier to understand. As long as the relationship of the relative direction or position by terms such as "upper" and "lower" in the referenced drawings is the same, the arrangement in drawings other than the present disclosure, in actual products, etc., may not be the same as that in the referenced drawings. In this specification, the positional relationship expressed as "upper (or lower)" includes, for example, when two members are assumed to exist, a case in which the two members are in contact with each other, and a case in which the two members are not in contact with each other and one member is located above (or below) the other member. In addition, unless otherwise specified, a member covering a covered object includes a case in which the member is in contact with the covered object and directly covers the covered object, and a case in which the member indirectly covers the covered object without contacting the covered object.

[0010] In the figures shown below, directions may be indicated by the X-axis, Y-axis, and Z-axis. The X-axis, Y-axis, and Z-axis are mutually perpendicular. For example, in this specification, the direction along the Z-axis is the first direction Z, the direction along the X-axis is the second direction X, and the direction along the Y-axis is the third direction Y.

[0011] [Light emitting element] 1, the light-emitting element 1 of the embodiment is, for example, rectangular and has, in plan view, two sides extending in the second direction X and two sides extending in the third direction Y. The length of one side of the light-emitting element 1 in plan view is, for example, 30 μm or more and 1000 μm or less.

[0012] 2, the light-emitting element 1 includes a semiconductor structure 10, a first electrode 61, a second electrode 62, a first reflective film 20, and a first protective film 40. Each component will be described in detail below.

[0013] <Semiconductor structure> The semiconductor structure 10 is made of a nitride semiconductor. In this specification, the term "nitride semiconductor" refers to, for example, In x Al y Ga 1-x-yIt includes all semiconductors with compositions in which the composition ratios x and y are changed within the respective ranges in the chemical formula N (0≦x≦1, 0≦y≦1, x+y≦1). In addition, in the above chemical formula, those that further contain Group V elements other than N (nitrogen) and those that further contain various elements added to control various physical properties such as the conductivity type are also included in the "nitride semiconductor".

[0014] The semiconductor structure 10 includes a first semiconductor layer 11, an active layer 12, and a second semiconductor layer 13. The first semiconductor layer 11 includes a semiconductor layer including an n-type impurity. The second semiconductor layer 13 includes a semiconductor layer including a p-type impurity. The active layer 12 is a light-emitting layer that emits light, and has, for example, an MQW (Multiple Quantum Well) structure including a plurality of barrier layers and a plurality of well layers. The active layer 12 emits light having, for example, a peak wavelength of 210 nm or more and 580 nm or less.

[0015] The first semiconductor layer 11 has a first surface 11A and a second surface 11B located on the opposite side to the first surface 11A in the first direction Z.

[0016] The first surface 11A is a surface of the light-emitting element 1 from which light is mainly extracted. The first surface 11A has a central region 11A1 and an outer peripheral region 11A2. As shown in FIG. 1, in a plan view, the central region 11A1 is surrounded by the outer peripheral region 11A2. In a plan view, the boundary between the central region 11A1 and the outer peripheral region 11A2 coincides with an inner edge 20D of the first reflective film 20 described later. In a plan view, the area of ​​the central region 11A1 is larger than the area of ​​the outer peripheral region 11A2. In a plan view, the outer peripheral region 11A2 is, for example, a region of the first surface 11A within a range of 10 μm, preferably within a range of 5 μm, from an outer edge 11C of the first surface 11A.

[0017] The light emitted by the active layer 12 can be extracted from the central region 11A1 to the outside of the semiconductor structure 10. The central region 11A1 is roughened, and the surface roughness of the central region 11A1 is greater than the surface roughness of the peripheral region 11A2. This can improve the efficiency of extracting light from the central region 11A1. The semiconductor structure 10 may be chipped near the outer edge of the semiconductor structure 10. In the embodiment, the surface roughness of the peripheral region 11A2 is smaller than the surface roughness of the central region 11A1, so that the strength of the first semiconductor layer 11 near the outer edge 11C on the first surface 11A can be increased and the occurrence of chipping in the first semiconductor layer 11 can be reduced, compared to when the surface roughness of the peripheral region 11A2 is the same as that of the central region 11A1 and when the surface roughness of the peripheral region 11A2 is greater than that of the central region 11A1. In this specification, the surface roughness is, for example, the average surface roughness Ra. The average surface roughness Ra of the central region 11A1 is, for example, 100 nm or more and 400 nm or less. The average surface roughness Ra of the peripheral region 11A2 is, for example, 1 nm or more and 10 nm or less. Here, the surface roughness of the central region 11A1 and the surface roughness of the peripheral region 11A2 can be measured by a laser microscope, an atomic force microscope, or the like.

[0018] The central region 11A1 can be roughened by dry etching or wet etching. When the central region 11A1 is roughened, the outer circumferential region 11A2 of the first surface 11A is covered with a mask for protection.

[0019] The second surface 11B has a first region 11B1 and a second region 11B2. In a plan view, the area of ​​the first region 11B1 is larger than the area of ​​the second region 11B2. The active layer 12 is disposed on the first region 11B1 of the second surface 11B. Note that in FIG. 2, the active layer 12 is illustrated as being located below the first region 11B1, and the active layer 12 being disposed on the surface of the first region 11B1 in this manner is referred to as "the active layer 12 being disposed on the first region 11B1 of the second surface 11B."

[0020] <First electrode and second electrode> The first electrode 61 is disposed in the second region 11B2 and is electrically connected to the first semiconductor layer 11. The second electrode 62 is disposed on the second semiconductor layer 13 and is electrically connected to the second semiconductor layer 13. The first electrode 61 and the second electrode 62 can be, for example, a single metal layer containing Ti, Rh, Au, Pt, Al, Ag, or Ru, or a laminated structure containing at least two of these metal layers.

[0021] <1st reflective film> The first reflective film 20 is disposed only in the peripheral region 11A2 of the first surface 11A of the semiconductor structure 10. The surface of the semiconductor structure 10 includes the first surface 11A of the first semiconductor layer 11, the upper surface 13A of the second semiconductor layer 13, the second region 11B2 of the second surface 11B of the first semiconductor layer 11, the side surface of the first semiconductor layer 11, the side surface of the active layer 12, and the side surface of the second semiconductor layer 13. The upper surface 13A of the second semiconductor layer 13 is the surface of the second semiconductor layer 13 located on the opposite side to the active layer 12. The first reflective film 20 is not disposed in the central region 11A1 of the first surface 11A, the upper surface 13A of the second semiconductor layer 13, the second region 11B2 of the second surface 11B, the side surface of the first semiconductor layer 11, the side surface of the active layer 12, and the side surface of the second semiconductor layer 13. The area other than the outer circumferential area 11A2 where the first reflective film 20 is arranged is, for example, an area on a second protective film 50 described later.

[0022] The first reflective film 20 has reflectivity for the light emitted by the active layer 12. The reflectance of the first reflective film 20 for the peak wavelength of the light emitted by the active layer 12 is, for example, 40% or more, preferably 60% or more. For example, a dielectric multilayer film can be used as the first reflective film 20. The material of the dielectric multilayer film will be described later. For example, a metal film containing aluminum or silver may be used as the first reflective film 20. By using a dielectric multilayer film as the first reflective film 20, it is possible to reduce light absorption in the first reflective film 20 compared to the case of using a metal film.

[0023] <1st protective film> The first protective film 40 is disposed in the central region 11A1 of the first surface 11A. The transmittance of the first protective film 40 for the peak wavelength of the light emitted by the active layer 12 is higher than the transmittance of the first reflective film 20 for the peak wavelength of the light emitted by the active layer 12. The transmittance of the first protective film 40 for the peak wavelength of the light emitted by the active layer 12 is, for example, 70% or more, preferably 90% or more. For example, SiO2 can be used as the first protective film 40. The light emitted by the active layer 12 is mainly extracted to the outside through the first protective film 40. The thickness of the first protective film 40 is, for example, 0.1 μm or more and 1 μm or less. Here, the thickness of the first protective film 40 means the maximum thickness of the first protective film 40 in the first direction Z.

[0024] By not roughening the outer peripheral region 11A2, the light emitted by the active layer 12 can be easily totally reflected at the interface between the outer peripheral region 11A2 and the first reflection film 20. Furthermore, by disposing the first reflection film 20 in the outer peripheral region 11A2, the light emitted by the active layer 12 can be reflected by the first reflection film 20. This makes it possible to increase the difference in luminance of light between the central region 11A1 and the outer peripheral region 11A2, which is located outside the central region 11A1, on the first surface 11A. In other words, when the light-emitting element 1 is observed from the first surface 11A side, the outer peripheral region 11A2 can be made darker than the central region 11A1. As a result, when the light-emitting element 1 is observed from the first surface 11A side, the difference in luminance between the light-emitting element 1 and the region adjacent to the light-emitting element 1 can be increased.

[0025] Light emitted by the active layer 12 can also be extracted to the outside through a side surface 10C of the semiconductor structure 10. The side surface 10C of the semiconductor structure 10 connects the first surface 11A of the first semiconductor layer 11 and the upper surface 13A of the second semiconductor layer 13, and connects the first surface 11A and the second region 11B2 of the second surface 11B.

[0026] No reflective film such as the first reflective film 20 is disposed on the side surface 10C of the semiconductor structure 10. If a reflective film is disposed on the side surface 10C, the light from the active layer 12 is reflected by the reflective film disposed on the side surface 10C and is easily absorbed by the semiconductor structure 10. As a result, the light extraction efficiency of the light-emitting element 1 is easily reduced. Therefore, by not disposing a reflective film on the side surface 10C of the semiconductor structure 10, the light extraction efficiency to the outside of the light-emitting element 1 can be increased. Note that, when the planar size of the light-emitting element 1 becomes small, the proportion of light extracted from the side surface 10C increases. Therefore, the structure in which a reflective film is not disposed on the side surface 10C is effective when the length of one side of the first surface 11A in a plan view is relatively small. For example, the effect is large when the length of one side of the first surface 11A in a plan view is 100 μm or less, and the effect is even greater when the length of one side of the first surface 11A in a plan view is 60 μm or less.

[0027] The first reflective film 20 may have, for example, a first dielectric multilayer film 25 shown in FIG. 3A. The first dielectric multilayer film 25 may include a plurality of first films 21 and a plurality of second films 22. The first films 21 and the second films 22 are alternately stacked in the first direction Z. For example, the first films 21 are Nb2O5, and the second films 22 are SiO2.

[0028] The first dielectric multilayer film 25 is preferably formed by pairing a first film 21 having a thickness of 10 nm or more and 100 nm or less with a second film 22 having a thickness of 10 nm or more and 100 nm or less, with the number of pairs being 2 or more and 6 or less. By setting the thickness of each film and the number of pairs of the first dielectric multilayer film 25 in this manner, high light reflectivity can be achieved. Furthermore, it is preferable that each of the multiple first films 21 has the same thickness. Furthermore, it is preferable that each of the multiple second films 22 has the same thickness.

[0029] The first reflective film 20 may further include a fifth film 23. The fifth film 23 is disposed on the outer peripheral region 11A2 of the first surface 11A, and the first film 21 and the second film 22 are alternately laminated on the fifth film 23. For example, the fifth film 23 is a SiO2 film. The thickness of the fifth film 23 is thicker than the thickness of the first film 21 and thicker than the thickness of the second film 22. The thickness of the fifth film 23 is, for example, 100 nm or more and 500 nm or less. Such a thick fifth film 23 can easily increase the effect of total reflection at the interface between the fifth film 23 and the outer peripheral region 11A2 of the first surface 11A.

[0030] For example, after forming a fifth film 23, which is a SiO2 film having a thickness of 100 nm, as the first reflective film 20, three pairs of a first film 21, which is Nb2O5 having a thickness of 57.2 nm, and a second film 22, which is SiO2 having a thickness of 91.3 nm, can be formed on top of the fifth film 23.

[0031] In FIG. 1, the outer edge 20C of the first reflection film 20 in plan view is represented by a solid line, and the outer edge 11C of the first surface 11A in plan view is represented by a dashed line. The outer edge 11C of the first surface 11A is located at the outermost edge of the semiconductor structure 10 in plan view. The first reflection film 20 can have a first portion 20A that overlaps with the peripheral region 11A2 in plan view, and a second portion 20B that extends from the first portion 20A to the outside of the semiconductor structure 10 in plan view. In plan view, the second portion 20B of the first reflection film 20 extends to the outside of the outer edge 11C of the first surface 11A. In this embodiment, the second portion 20B is disposed in contact with a second protective film 50 described later. The second portion 20B of the first reflective film 20 makes it easier to reflect light exiting from the side surface 10C of the semiconductor structure 10, thereby increasing the difference in light brightness between the central region 11A1 and the regions outside the central region 11A1.

[0032] In a plan view, the area of ​​the second portion 20B is preferably smaller than the area of ​​the first portion 20A. This makes it possible to make the first reflective film 20 less likely to chip. The extension length of the second portion 20B from the outer peripheral region 11A2 in the second direction X is preferably shorter than the length of the first portion 20A in the second direction X. The extension length of the second portion 20B from the outer peripheral region 11A2 in the third direction Y is preferably shorter than the length of the first portion 20A in the third direction Y. The extension length of the second portion 20B from the outer peripheral region 11A2 in the second direction X and the extension length of the second portion 20B in the third direction Y in the second direction X and the third direction Y in the third direction Y are preferably 1 μm or less.

[0033] As shown in FIG. 2, the first protective film 40 can be disposed continuously on the central region 11A1 and the first reflective film 20 on the peripheral region 11A2. The first protective film 40 covers the central region 11A1 along the multiple convex portions of the central region 11A1, and multiple convex portions are also formed on the upper surface of the first protective film 40. The surface roughness of the first protective film 40 on the central region 11A1 is larger than the surface roughness of the first protective film 40 on the first reflective film 20. This can improve the extraction efficiency of the light incident on the first protective film 40 from the central region 11A1 from the first protective film 40. Since the surface roughness of the first protective film 40 on the first reflective film 20 is smaller than the surface roughness of the first protective film 40 on the central region 11A1, the light passing through the first reflective film 20 can be easily totally reflected at the interface between the first protective film 40 on the first reflective film 20 and, for example, an air layer or a resin layer.

[0034] <Second protective film> The light-emitting element 1 may further include a second protective film 50. The second protective film 50 is disposed on the side surface 10C of the semiconductor structure 10 and covers the side surface 10C of the semiconductor structure 10. The transmittance of the second protective film 50 for the peak wavelength of the light emitted by the active layer 12 is higher than the transmittance of the first reflective film 20 for the peak wavelength of the light emitted by the active layer 12. The transmittance of the second protective film 50 for the peak wavelength of the light emitted by the active layer 12 is, for example, 70% or more, preferably 90% or more. For example, a SiO2 film can be used as the second protective film 50. The thickness of the second protective film 50 is, for example, 0.2 μm or more and 2 μm or less.

[0035] As shown in FIG. 1, in a plan view, the outer edge 50C of the second protective film 50 coincides with the outer edge 20C of the first reflective film 20. Alternatively, in a plan view, the outer edge 50C of the second protective film 50 is located inside the outer edge 20C of the first reflective film 20. In other words, the upper end surface 50A of the second protective film 50 is covered with the first reflective film 20. Light that enters the second protective film 50 from the side surface 10C of the semiconductor structure 10 and travels through the second protective film 50 toward the upper end surface 50A can be reflected by the first reflective film 20. This can increase the difference in light luminance between the central region 11A1 and the region outside the central region 11A1.

[0036] In a plan view, an outer edge 40C of the first protective film 40 coincides with an outer edge 50C of the second protective film 50 and an outer edge 20C of the first reflective film 20.

[0037] <Second reflective film> The light emitting element 1 may further include a second reflective film 30. The second reflective film 30 covers at least the upper surface 13A side of the second semiconductor layer 13. The second reflective film 30 has reflectivity to the light emitted by the active layer 12. The reflectance of the second reflective film 30 to the peak wavelength of the light emitted by the active layer 12 is, for example, 40% or more, preferably 60% or more. The light that travels from the active layer 12 to the upper surface 13A side of the second semiconductor layer 13 can be reflected by the second reflective film 30 toward the central region 11A1 of the first surface 11A. This can improve the efficiency of extracting light from the central region 11A1.

[0038] The second reflective film 30 can cover substantially the entire surface of the surface opposite to the first surface 11A of the semiconductor structure 10. This increases the amount of light reflected toward the central region 11A1, thereby further improving the efficiency of extracting light from the central region 11A1.

[0039] It is preferable that the second reflection film 30 overlaps with the first reflection film 20 in a plan view. As shown in FIG. 1, in a plan view, an outer edge 30C of the second reflection film 30 is located between an inner edge 20D of the first reflection film 20 and an outer edge 20C of the first reflection film 20. By overlapping the second reflection film 30 with the first reflection film 20 in a plan view, the light reflected by the first reflection film 20 and directed downward is reflected by the second reflection film 30 toward the central region 11A1, and the light extraction efficiency from the central region 11A1 can be improved. In a plan view, the area where the first reflection film 20 and the second reflection film 30 overlap is preferably 40% or more of the area of ​​the first reflection film 20.

[0040] The second reflective film 30 may have, for example, a second dielectric multilayer film 35 shown in FIG. 3B. The second dielectric multilayer film 35 may include a plurality of third films 31 and a plurality of fourth films 32. The third films 31 and the fourth films 32 are alternately stacked in the first direction Z. For example, the third film 31 is Nb2O5, and the fourth film 32 is SiO2.

[0041] The second dielectric multilayer film 35 is preferably formed by pairing a third film 31 having a thickness of 10 nm or more and 100 nm or less with a fourth film 32 having a thickness of 10 nm or more and 100 nm or less, with the number of pairs being 2 or more and 6 or less. By setting the thickness of each film and the number of pairs of the second dielectric multilayer film 35 in this manner, good light reflectivity can be achieved. Furthermore, it is preferable that each of the multiple third films 31 has the same thickness. Furthermore, it is preferable that each of the multiple fourth films 32 has the same thickness.

[0042] The second reflective film 30 may further include a sixth film 33. The sixth film 33 is disposed closer to the semiconductor structure 10 than the second dielectric multilayer film 35, and the third film 31 and the fourth film 32 are alternately laminated on the sixth film 33. For example, the sixth film 33 is a SiO2 film. The thickness of the sixth film 33 is thicker than the thickness of the third film 31 and thicker than the thickness of the fourth film 32. The thickness of the sixth film 33 is, for example, 100 nm or more and 500 nm or less. Such a thick sixth film 33 can easily increase the effect of total reflection at the interface between the sixth film 33 and the semiconductor structure 10.

[0043] For example, after forming a sixth film 33 made of SiO2 and having a thickness of 300 nm as the second reflective film 30, three pairs of films can be formed on top of the sixth film 33, each consisting of a third film 31 made of Nb2O5 and having a thickness of 52 nm, and a fourth film 32 made of SiO2 and having a thickness of 83 nm.

[0044] <Third reflective film> The light-emitting element 1 may further include a third reflective film 80 disposed on the second reflective film 30. The third reflective film 80 has reflectivity for light emitted from the active layer 12. The third reflective film 80 reflects light transmitted through the second reflective film 30 toward the central region 11A1, improving the light extraction efficiency. The third reflective film 80 is, for example, a metal film. The third reflective film 80 includes, for example, Al, Ti, or a laminated structure thereof.

[0045] <Transparent conductive film> The light-emitting element 1 may further include a translucent conductive film 90. The translucent conductive film 90 is disposed on the upper surface 13A of the second semiconductor layer 13. The second electrode 62 is disposed on the translucent conductive film 90. The second semiconductor layer 13 is electrically connected to the second electrode 62 via the translucent conductive film 90. The translucent conductive film 90 has a function of diffusing a current supplied through the second electrode 62 in the surface direction of the second semiconductor layer 13. Examples of materials that can be used for the translucent conductive film 90 include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ZnO, and In2O3. The translucent conductive film 90 has a thickness of, for example, 0.03 μm or more and 0.3 μm or less.

[0046] <First conductive member and second conductive member> The light-emitting element 1 may further include a first conductive member 71 and a second conductive member 72. The first conductive member 71 is electrically connected to the first electrode 61. As described later with reference to FIG. 4, the first conductive member 71 and the second conductive member 72 are electrically connected to the wiring board 101 via a connection member 110 such as a solder or a bump. The second conductive member 72 is electrically connected to the second electrode 62. The first conductive member 71 and the second conductive member 72 include, for example, Ti, Rh, Au, Pt, Ru, Al, or a laminated structure of any two of these.

[0047] The second protective film 50 can be disposed on the surface side of the semiconductor structure 10 opposite to the first surface 11A so as to cover the second reflective film 30, the third reflective film 80, the first electrode 61, and the second electrode 62. The first conductive member 71 and the second conductive member 72 are disposed in contact with the second protective film 50. The first conductive member 71 and the second conductive member 72 are disposed spaced apart from each other. The first conductive member 71 can be connected to the first electrode 61 at a first opening 50a formed in the second protective film 50, and the second conductive member 72 can be connected to the second electrode 62 at a second opening 50b formed in the second protective film 50.

[0048] [Light emitting device] The light emitting device 100 according to the embodiment will be described with reference to FIG.

[0049] The light emitting device 100 includes a wiring board 101, the above-mentioned light emitting element 1 arranged on the wiring board 101, and a wavelength conversion member 120 arranged on the light emitting element 1. For example, a plurality of light emitting elements 1 are arranged on the wiring board 101. Although two light emitting elements 1 are shown in FIG. 4, three or more light emitting elements 1 may be arranged on the wiring board 101. Each light emitting element 1 is arranged on the wiring board 101 with the first conductive member 71 and the second conductive member 72 facing the upper surface of the wiring board 101.

[0050] The wiring board 101 has an insulating base material 102 and a wiring portion 103 arranged on at least the upper surface of the insulating base material 102. Each of the first conductive member 71 and the second conductive member 72 of the light-emitting element 1 is joined to the wiring portion 103 via a connecting member 110, and is electrically connected to the wiring portion 103. For example, Cu, Au, or the like can be used as the connecting member 110. Each of the multiple light-emitting elements 1 can be individually controlled to light up.

[0051] The wavelength conversion member 120 is disposed continuously on the upper surface of each of the light emitting elements 1 and on the region between the adjacent light emitting elements 1 so as to straddle the plurality of light emitting elements 1. The wavelength conversion member 120 contacts the upper surface of the first protective film 40 while filling the gaps between the plurality of convex portions on the upper surface of the first protective film 40 on the central region 11A1 of the first surface 11A. The wavelength conversion member 120 includes, for example, a base material made of a light-transmitting material, and a phosphor dispersed in the base material. The material of the base material may be, for example, an epoxy resin, a silicone resin, a resin mixture of these, or glass. The color of the light wavelength-converted by the phosphor is, for example, yellow. The yellow phosphor may be, for example, Y3Al5O 12 : Ce or (Y,Lu,Gd)3(Al,Ga)5O 12 For example, a phosphor having a composition represented by the formula: Ce can be used. When a yellow phosphor having such a composition is used, the peak wavelength of light emitted from active layer 12 is preferably, for example, not less than 420 nm and not more than 490 nm.

[0052] When the wavelength conversion member 120 is disposed on the light emitting element 1, the thickness of the first reflection film 20 is preferably thicker than the thickness of the second reflection film 30. This makes it easier for the first reflection film 20 to reflect the wavelength-converted light, which is wavelength-converted by the wavelength conversion member 120 and has a longer wavelength than the light emitted by the active layer 12, upward from the light emitting element 1. As a result, the brightness of the light emitting device 100 can be increased. When the wavelength conversion member 120 is disposed on the light emitting element 1, the thickness of the first reflection film 20 is preferably 1.05 times or more and 1.2 times or less than the thickness of the second reflection film 30. When the first reflection film 20 has the first dielectric multilayer film 25 and the second reflection film 30 has the second dielectric multilayer film 35, the thickness of the first film 21 is preferably thicker than the thickness of the third film 31, and the thickness of the second film 22 is preferably thicker than the thickness of the fourth film 32. This makes it possible to increase the reflectance of the second reflective film 30 for the peak wavelength of light emitted from the active layer 12, while increasing the reflectance of the first reflective film 20 for the peak wavelength of light whose wavelength has been converted by the wavelength conversion member 120. The reflectance of the first reflective film 20 for the peak wavelength of light whose wavelength has been converted by the wavelength conversion member 120 is, for example, 40% or more, and preferably 60% or more.

[0053] As described above, when the light-emitting element 1 is observed from the first surface 11A side, the difference in luminance between the light-emitting element 1 and the area adjacent to the light-emitting element 1 is large. Therefore, when the light-emitting elements 1 of the light-emitting device 100 are individually controlled to be lit, it is possible to reduce the incidence of light emitted by the light-emitting element 1 entering the wavelength conversion member 120 on the adjacent light-emitting element 1 that is not caused to emit light, causing the phosphor contained in the wavelength conversion member 120 on the light-emitting element 1 that is not caused to emit light to emit light. This makes it possible to provide a light-emitting device 100 in which the difference in luminance between the wavelength conversion member 120 on the light-emitting element 1 that is caused to emit light and the wavelength conversion member 120 on the light-emitting element 1 that is not caused to emit light is large when the light-emitting device 100 is observed from the wavelength conversion member 120 side.

[0054] The light emitting device 100 may further include a sealing member 130 disposed between the plurality of light emitting elements 1 on the wiring substrate 101. The sealing member 130 is disposed between the light emitting element 1 and the upper surface of the wiring substrate 101. The sealing member 130 has, for example, reflectivity to light emitted by the active layer 12 and the wavelength conversion member 120. The reflectance of the sealing member 130 to the peak wavelength of light emitted by the active layer 12 is, for example, 60% or more, preferably 80% or more. The reflectance of the sealing member 130 to the peak wavelength of light emitted by the wavelength conversion member 120 is, for example, 60% or more, preferably 80% or more. The wavelength conversion member 120 is also disposed on the upper surface of the sealing member 130 located between adjacent light emitting elements 1. The sealing member 130 includes, for example, a base material and a light diffusing agent capable of diffusing and reflecting the light emitted by the active layer 12 and the wavelength conversion member 120. For example, a silicone resin, an epoxy resin, an acrylic resin, or the like can be used as the material of the base material of the sealing member 130. The light diffusing agent of the sealing member 130 may be, for example, particles of TiO2, SiO2, Al2O3, ZnO, MgO, ZrO2, Y2O3, CaF2, MgF2, Nb2O5, BaTiO3, Ta2O5, BaSO4, or glass.

[0055] Embodiments of the present invention may include the following light emitting devices.

[0056] [Section 1] a semiconductor structure comprising: a first semiconductor layer having a first surface and a second surface opposite the first surface, the second surface having a first region and a second region; an active layer disposed on the first region; and a second semiconductor layer disposed on the active layer; a first electrode disposed in the second region and electrically connected to the first semiconductor layer; a second electrode disposed on the second semiconductor layer and electrically connected to the second semiconductor layer; Equipped with the first surface has an outer circumferential region and a central region that is surrounded by the outer circumferential region in a plan view and has a surface roughness greater than that of the outer circumferential region; a first reflective film is disposed only on the outer periphery region of the surface of the semiconductor structure; a first protective film having a higher transmittance for the peak wavelength of light emitted by the active layer than the first reflective film is disposed in the central region; [Section 2] Item 2. The light-emitting device according to item 1, wherein the first reflective film has a first portion that overlaps with the outer circumferential region in a plan view, and a second portion that extends from the first portion to an outside of the semiconductor structure in a plan view. [Section 3] 3. The light emitting device according to item 2, wherein an area of ​​the second portion is smaller than an area of ​​the first portion in a plan view. [Section 4] a second protective film disposed on a side surface of the semiconductor structure connecting the first surface and an upper surface of the second semiconductor layer; 4. The light emitting device according to any one of items 1 to 3, wherein an outer edge of the second protective film coincides with an outer edge of the first reflective film or is located inside the outer edge of the first reflective film in a plan view. [Section 5] 5. The light-emitting device according to any one of items 1 to 4, wherein the first reflective film has a first dielectric multilayer film including a plurality of first films and a plurality of second films. [Section 6] Further comprising a second reflective film covering the second semiconductor layer, the second reflective film has a second dielectric multilayer film including a plurality of third films and a plurality of fourth films; The thickness of the first film is greater than the thickness of the third film, Item 6. The light-emitting device according to item 5, wherein the second film is thicker than the fourth film. [Section 7] the first protective film is disposed continuously on the central region and on the first reflective film on the outer circumferential region; 7. The light-emitting element according to any one of items 1 to 6, wherein a surface roughness of the first protective film on the central region is greater than a surface roughness of the first protective film on the first reflective film. [Section 8] a second reflective film covering the second semiconductor layer and overlapping the first reflective film in a plan view; 8. The light emitting device according to any one of items 1 to 7, wherein an area where the first reflective film and the second reflective film overlap in a plan view is 40% or more of an area of ​​the first reflective film.

[0057] The above describes the embodiments of the present invention with reference to specific examples. However, the present invention is not limited to these specific examples. All forms that can be implemented by a person skilled in the art through appropriate design modifications based on the above-described embodiments of the present invention also belong to the scope of the present invention as long as they include the gist of the present invention. In addition, within the scope of the concept of the present invention, a person skilled in the art may come up with various modified examples and examples of modifications, and these modified examples and examples of modifications also belong to the scope of the present invention. [Explanation of symbols]

[0058] 1...light emitting element, 10...semiconductor structure, 10C...side surface, 11...first semiconductor layer, 11A...first surface, 11A1...central region, 11A2...peripheral region, 11B...second surface, 11B1...first region, 11B2...second region, 12...active layer, 13...second semiconductor layer, 20...first reflective film, 20A...first portion, 20B...second portion, 21...first film, 22...second film, 23...fifth film, 25...first dielectric multilayer film, 3 0...second reflective film, 31...third film, 32...fourth film, 33...sixth film, 35...second dielectric multilayer film, 40...first protective film, 50...second protective film, 61...first electrode, 62...second electrode, 71...first conductive member, 72...second conductive member, 80...third reflective film, 90...translucent conductive film, 100...light emitting device, 101...wiring board, 102...insulating base material, 103...wiring section, 120...wavelength conversion member, 130...sealing member

Claims

1. a semiconductor structure including a first semiconductor layer having a first surface and a second surface opposite the first surface, the second surface having a first region and a second region; an active layer disposed on the first region; and a second semiconductor layer disposed on the active layer; a first electrode disposed in the second region and electrically connected to the first semiconductor layer; a second electrode disposed on the second semiconductor layer and electrically connected to the second semiconductor layer; Equipped with the first surface has an outer circumferential region and a central region that is surrounded by the outer circumferential region in a plan view and has a surface roughness greater than that of the outer circumferential region; A first reflective film is disposed only on the outer periphery region of the surface of the semiconductor structure; a first protective film having a higher transmittance than the first reflective film for the peak wavelength of light emitted by the active layer, disposed in the central region;

2. The light-emitting element according to claim 1 , wherein the first reflective film has a first portion that overlaps with the outer periphery region in a plan view, and a second portion that extends from the first portion to an outside of the semiconductor structure in a plan view.

3. The light-emitting element according to claim 2 , wherein an area of ​​the second portion is smaller than an area of ​​the first portion in a plan view.

4. a second protective film disposed on a side surface of the semiconductor structure connecting the first surface and an upper surface of the second semiconductor layer; 4. The light-emitting element according to claim 1, wherein, in a plan view, an outer edge of the second protective film coincides with an outer edge of the first reflective film or is located inside the outer edge of the first reflective film.

5. 4. The light-emitting element according to claim 1, wherein the first reflective film has a first dielectric multilayer film including a plurality of first films and a plurality of second films.

6. Further comprising a second reflective film covering the second semiconductor layer, the second reflective film has a second dielectric multilayer film including a plurality of third films and a plurality of fourth films; The thickness of the first film is greater than the thickness of the third film, The light-emitting element according to claim 5 , wherein the second film is thicker than the fourth film.

7. the first protective film is disposed continuously on the central region and on the first reflective film on the peripheral region; 4. The light-emitting element according to claim 1, wherein a surface roughness of said first protective film on said central region is greater than a surface roughness of said first protective film on said first reflective film.

8. a second reflective film covering the second semiconductor layer and overlapping the first reflective film in a plan view; 4. The light-emitting element according to claim 1, wherein an area where the first reflective film and the second reflective film overlap in a plan view is 40% or more of an area of ​​the first reflective film.

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