Light-emitting element and light-emitting device

Abstract

The purpose of the present invention is to provide a light-emitting element and a light-emitting device capable of extracting light more efficiently. A light emitting element includes: a substrate; a semiconductor structure disposed on the substrate and including, in order from the substrate side, an n-side semiconductor layer, an active layer, and a p-side semiconductor layer; a p electrode disposed on the p-side semiconductor layer and electrically connected to the p-side semiconductor layer; an n-electrode disposed on the n-side semiconductor layer and electrically connected to the n-side semiconductor layer; the n electrode includes a base portion and a plurality of extension portions extending from the base portion, the substrate includes exposed portions exposed from the semiconductor structure, and in a plan view, the exposed portions include: a first exposed portion located between two adjacent extension portions; a second exposed portion disposed on an outer peripheral portion of the substrate and connected to the first exposed portion; in a plan view, the p electrode is disposed between the extending portion and the first exposed portion.

Description

Technical Field

[0001] The present invention relates to a light emitting element and a light emitting device. Background Art

[0002] In the past, a light-emitting element has been proposed, which includes: a semiconductor structure having an n-type semiconductor layer, an active layer and a p-type semiconductor layer stacked in a manner that a portion of the n-type semiconductor layer is exposed; and an n-electrode and a p-electrode provided on one side of the semiconductor structure. In such a light-emitting element, a deviation in current diffusion in the semiconductor structure occurs due to the composition of the semiconductor structure, and therefore various designs are made to achieve a uniform current density within the surface.

[0003] For example, a method has been proposed in which a trench is provided between electrodes connected to a semiconductor structure to control the flow of horizontal current (for example, Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: (Japan) Patent Publication No. 2010-530628 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a light-emitting element and a light-emitting device capable of extracting light more efficiently.

[0009] Solutions to Solve Problems

[0010] The present disclosure includes the following inventions.

[0011] (1) A light emitting element comprising:

[0012] substrate;

[0013] A semiconductor structure, which is arranged on the substrate and includes, in order from the substrate side, an n-side semiconductor layer, an active layer and a p-side semiconductor layer;

[0014] A p-electrode, which is disposed on the p-side semiconductor layer and is electrically connected to the p-side semiconductor layer;

[0015] An n-electrode is disposed on the n-side semiconductor layer and is electrically connected to the n-side semiconductor layer;

[0016] The n-electrode includes a base portion and a plurality of extension portions extending from the base portion,

[0017] The substrate includes an exposed portion exposed from the semiconductor structure.

[0018] In a plan view, the exposed portion includes: a first exposed portion located between two adjacent extending portions; a second exposed portion disposed at the outer periphery of the substrate and connected to the first exposed portion;

[0019] The p-electrode is arranged between the extending portion and the first exposed portion in a plan view.

[0020] (2) A light emitting device comprising:

[0021] The above-mentioned light-emitting element;

[0022] A covering member covers at least the side surface of the n-side semiconductor layer and the side surface of the active layer adjacent to the exposed portion in a plan view.

[0023] Effects of the Invention

[0024] According to the light emitting element and the light emitting device according to one embodiment of the present invention, it is possible to provide a light emitting element and a light emitting device capable of extracting light more efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is a plan view schematically showing a light emitting element according to an embodiment of the present disclosure.

[0026] Figure 2 yes Figure 1 Sectional view along line II-II.

[0027] Figure 3 is a plan view schematically showing a light emitting element according to another embodiment of the present disclosure.

[0028] Figure 4 1 is a plan view schematically showing a light emitting element according to still another embodiment of the present disclosure.

[0029] Figure 5 1 is a top view schematically showing a light emitting device according to an embodiment of the present disclosure.

[0030] Figure 6 yes Figure 5 VI-VI line section view.

[0031] Fig. 7A It is a cross-sectional view for explaining a method for manufacturing one embodiment of the light emitting device of the present disclosure.

[0032] Figure 7B It is a cross-sectional view for explaining a method for manufacturing one embodiment of the light emitting device of the present disclosure.

[0033] Figure 7CIt is a cross-sectional view for explaining a method for manufacturing one embodiment of the light emitting device of the present disclosure.

[0034] Fig.7D It is a cross-sectional view for explaining a method for manufacturing one embodiment of the light emitting device of the present disclosure.

[0035] Fig. 7E It is a cross-sectional view for explaining a method for manufacturing one embodiment of the light emitting device of the present disclosure.

[0036] Figure 7F It is a cross-sectional view for explaining a method for manufacturing one embodiment of the light emitting device of the present disclosure. DETAILED DESCRIPTION

[0037] Since the drawings referred to in the following description are drawings that schematically show the implementation methods, there are cases where the proportions, intervals, positional relationships, etc. of the various components are exaggerated, or the illustration of a part of the component is omitted. In addition, in the top view and its cross-sectional view, there are also inconsistencies in the proportions and intervals of the various components. In the following description, the same names and figure marks in principle indicate the same or homogeneous components, or components with the same functions, and sometimes detailed descriptions are appropriately omitted. In the specification and drawings of this application, the first direction refers to a direction parallel to one side of the semiconductor structure 15, which is the direction indicated by the arrow F. Similarly, the second direction refers to a direction orthogonal to the first direction, which is the direction indicated by the arrow S.

[0038] [Light-emitting element 10]

[0039] For example, Figure 1 as well as Figure 2 As shown, a light-emitting element of an embodiment of the present disclosure includes: a substrate 11; a semiconductor structure 15, which is arranged on the substrate 11, and includes an n-side semiconductor layer 12, an active layer 13 and a p-side semiconductor layer 14 in sequence from the substrate 11 side; a p-electrode 16, which is arranged on the p-side semiconductor layer 14 and electrically connected to the p-side semiconductor layer 14; and an n-electrode 17, which is arranged on the n-side semiconductor layer 12 and electrically connected to the n-side semiconductor layer 12.

[0040] The n-electrode 17 includes a base portion 17A and a plurality of extension portions 17B extending from the base portion 17A.

[0041] The substrate 11 includes an exposed portion 11A exposed from the semiconductor structure 15. In a plan view, the exposed portion 11A includes: a first exposed portion 11A1 located between two adjacent extension portions 17B; and a second exposed portion 11A2 disposed at the outer periphery of the substrate 11 and connected to the first exposed portion 11A1. In a plan view, the p-electrode 16 is disposed between the extension portion 17B and the first exposed portion 11A1.

[0042] In this way, the light emitting element of one embodiment of the present disclosure is provided with the first exposed portion 11A1 as the exposed portion 11A of the substrate 11 between two adjacent extension portions 17B. As a result, compared with the light emitting element in which the exposed portion 11A is provided only on the periphery of the semiconductor structure 15, it is possible to reduce the absorption of the light emitted from the active layer 13 by the semiconductor structure 15, and to more efficiently extract the light from the side of the semiconductor structure 15. As a result, the efficiency of extracting light from the light emitting element is improved, and a light emitting element with high brightness can be provided. In addition, by connecting the first exposed portion 11A1 and the second exposed portion 11A2, as described later, when the side of the semiconductor structure 15 is covered by the covering member 21, the covering member 21 can be easily arranged relative to the side of the semiconductor structure 15. Therefore, the light emitted from the side of the semiconductor structure 15 can be efficiently reflected by the covering member 21 to the light extraction surface side, and the light extraction efficiency of the light emitting device is further improved.

[0043] (Semiconductor structure 15)

[0044] The semiconductor structure 15 includes an n-side semiconductor layer 12, an active layer 13, and a p-side semiconductor layer 14 in order from the substrate 11 side. The upper surface of the n-side semiconductor layer 12 has an area where the active layer 13 and the p-side semiconductor layer 14 are configured and an area where the active layer 13 and the p-side semiconductor layer 14 are not configured. The upper surface of the n-side semiconductor layer 12 has an area exposed from the active layer 13 and the p-side semiconductor layer 14. In this way, the area where the upper surface of the n-side semiconductor layer 12 is exposed from the active layer 13 and the p-side semiconductor layer 14 is called an n-layer exposed portion. When viewed from above, the n-layer exposed portion is surrounded by the active layer 13 and the p-side semiconductor layer 14. The n-electrode 17 is electrically connected to the n-side semiconductor layer 12 at the n-layer exposed portion.

[0045] The shape, size, position and number of the n-layer exposed portion can be appropriately set according to the size, shape, electrode shape, etc. of the desired light-emitting element. For example, when viewed from above, the shape of the n-layer exposed portion can be circular, elliptical, or a polygon such as a triangle, quadrilateral, hexagon, or a combination of these shapes. Preferably, the n-layer exposed portion is configured symmetrically with respect to the center point of the substrate 11, or is configured symmetrically with respect to a line bisecting a side of the substrate 11. By electrically connecting the n-electrode 17 to the n-layer exposed portion configured in this way, deviations in the current density distribution can be suppressed. As a result, as a whole, uneven brightness of the light-emitting element can be suppressed. It should be noted that in this specification, "brightness" refers to "radiant brightness" in the case of a light-emitting element that emits ultraviolet light or infrared light.

[0046] Preferably, in plan view, the area of ​​the n-layer exposed portion is, for example, 30% or less, 25% or less, 20% or less, or 15% or less of the total area of ​​the semiconductor structure 15. By setting such a range, the area of ​​the active layer 13 can be maintained and the brightness can be improved.

[0047] The semiconductor structure 15 can include various semiconductors such as III-V compound semiconductors and II-VI compound semiconductors. Specifically, nitride-based semiconductor materials such as InXAlYGa1-X-YN (0≤X, 0≤Y, X+Y≤1) can be included, and InN, AlN, GaN, InGaN, AlGaN, InGaAlN, etc. can be used. The film thickness, layer structure and composition of each layer can use the film thickness, layer structure and composition of each layer known in the field. The peak emission wavelength of the light-emitting element can be any one of visible light, ultraviolet light and infrared light. For example, in the case of a light-emitting element that emits ultraviolet light, the active layer 13 and the n-side semiconductor layer 12 preferably include a semiconductor layer made of AlGaN with an Al composition ratio of more than 30%. In addition, the peak emission wavelength of the light from the active layer 13 is more preferably greater than 250nm and less than 330nm. The light-emitting element 10 that emits ultraviolet light can be used for sterilization, disinfection, etc.

[0048] The planar shape of the semiconductor structure 15 may be, for example, a polygon such as a quadrilateral or hexagon, a circle, an ellipse, etc. The outer edge of the semiconductor structure 15 is arranged inside the outer edge of the substrate 11 in a plan view.

[0049] (Substrate 11)

[0050] The substrate 11 supports the semiconductor structure 15. The substrate 11 may include a substrate capable of epitaxially growing a semiconductor layer included in the semiconductor structure 15. As the material of the substrate 11, insulating substrates such as sapphire (Al2O3) and spinel (MgA12O4), nitride-based semiconductor substrates such as AlN and GaN, etc. may be mentioned. When a nitride semiconductor is used in the semiconductor structure 15, it is preferred to use a sapphire substrate having a C-plane as a growth plane. In addition, it may be a substrate having an angle of deviation of more than 0° and less than 10° relative to the C-plane of the sapphire substrate. The substrate 11 may be a substrate having a plurality of protrusions on the upper surface on which the semiconductor structure 15 is arranged.

[0051] The planar shape of the substrate 11 may be, for example, a polygon such as a quadrilateral or hexagon, a circle, or an ellipse, and is preferably a rectangle, a hexagon, or a shape having rounded corners.

[0052] The upper surface of the substrate 11 includes an exposed portion 11A exposed from the semiconductor structure 15. The exposed portion 11A has a first exposed portion 11A1 located between two adjacent extension portions 17B and a second exposed portion 11A2 exposed from the semiconductor structure 15 at the outer periphery of the substrate 11. The second exposed portion 11A2 is a region where the substrate 11 is exposed between the outer edge of the semiconductor structure 15 and the outer edge of the substrate 11. The first exposed portion 11A1 is connected to the second exposed portion 11A2. The second exposed portion 11A2 may be configured only at a portion of the outer periphery of the substrate 11, or preferably configured to surround the semiconductor structure 15.

[0053] It is preferred that two or more first exposed portions 11A1 are arranged in one semiconductor structure 15, and it is more preferred that three or more first exposed portions 11A1 are arranged. In the case where a plurality of first exposed portions 11A1 are arranged, it is preferred that all first exposed portions 11A1 are connected to the second exposed portion 11A2. Thus, the cover member 21 described later can be arranged on the side of the semiconductor structure 15 adjacent to the first exposed portion 11A1 and the second exposed portion 11A2. As a result, the light from the side of the semiconductor structure 15 can be efficiently reflected by the cover member 21 to the light extraction surface side, further improving the brightness of the light-emitting element.

[0054] like Figure 1 As shown in FIG. 1 , the exposed portion 11A includes a second exposed portion 11A2 disposed on the outer periphery of the quadrilateral substrate 11. The exposed portion 11A includes a first exposed portion 11A1 disposed in connection with the second exposed portion 11A2. Figure 1 In the embodiment, the first exposed portion 11A1 extends along the second direction S at three positions that divide the sides of the substrate 11 parallel to the first direction F into four equal parts. In addition, the first exposed portion 11A1 extends along the first direction F from three positions that divide the sides of the substrate 11 parallel to the second direction S into four equal parts. The first exposed portion 11A1 extending along the second direction S from a position that divides the sides of the substrate 11 parallel to the first direction F into two equal parts has a portion extending along the first direction F. In addition, the first exposed portion 11A1 extending along the first direction F from a position that divides the sides of the substrate 11 parallel to the second direction S into two equal parts has a portion extending along the second direction S.

[0055] Three first exposed portions 11A1 connected to the second exposed portion 11A2 are arranged on each side of the substrate 11, for a total of 12. The length of the first exposed portion 11A1 is, for example, 5% to 45% of the length of one side of the substrate 11. Figure 1 The exposed portion 11A shown in FIG. 1 is arranged point-symmetrically with respect to the center of the substrate 11 .

[0056] The width of the first exposed portion 11A1 extending along the first direction F in the second direction S and the width of the first exposed portion 11A1 extending along the second direction S in the first direction F can be, for example, greater than 0.2% and less than 5% of one side of the substrate 11. The width of the second exposed portion 11A2 extending along the first direction F in the second direction S and the width of the second exposed portion 11A2 extending along the second direction S in the first direction F can be, for example, greater than 0.5% and less than 10% of one side of the substrate 11. The widths of the plurality of first exposed portions 11A1 can be all the same or different. In addition, the widths of the plurality of second exposed portions 11A2 can be all the same or different.

[0057] The shape, size, position, etc. of the exposed portion 11A can be appropriately set according to the size, shape, electrode shape, etc. of the light emitting element. In addition, the shape, size, position, etc. of the exposed portion 11A can be appropriately set according to the size of the semiconductor structure 15, the required output and brightness of the light emitting element, etc.

[0058] When viewed from above, the area of ​​the exposed portion 11A can be, for example, less than 30%, less than 25%, less than 20%, or less than 15% of the total area of ​​the substrate 11. By setting it within such a range, the area of ​​the active layer 13 can be maintained and the brightness can be improved. Specifically, the area of ​​the first exposed portion 11A1 can be more than 0.5% and less than 10% of the total area of ​​the substrate 11. The area of ​​the second exposed portion 11A2 can be, for example, more than 1% and less than 20% of the total area of ​​the substrate 11. By setting it within such a range, the area of ​​the active layer 13 in the light-emitting element 10 can be maintained and the brightness can be improved.

[0059] It is preferable that there is one semiconductor structure 15 disposed on the substrate 11. The semiconductor structure 15 being one means that the semiconductor structure 15 is not separated by the arrangement of the exposed portion 11A in a plan view.

[0060] By regularly arranging the exposed portions 11A, it is possible to suppress the deviation of the current density distribution of the light-emitting element 10. As a result, the brightness unevenness of the light-emitting element as a whole can be suppressed. In particular, as described later, at least one first exposed portion 11A1 is preferably arranged between at least two extension portions 17B, and more preferably, all first exposed portions 11A1 are arranged between any extension portions 17B. By such an arrangement, it is possible to further suppress the deviation of the current density distribution, and the brightness unevenness of the light-emitting element as a whole can be suppressed.

[0061] exist Figure 3In the light-emitting element of another embodiment of the present disclosure shown, the exposed portion 11A has two first exposed portions 11A1 extending along the first direction F and a second exposed portion 11A2 arranged at the outer periphery of the quadrilateral substrate 11. The two first exposed portions 11A1 extend from the second exposed portion 11A2 along the first direction F, respectively, and the second exposed portion 11A2 is located at a position of 1 / 3 of the length of the side and a position of 2 / 3 of the length of the side from one end of the quadrilateral substrate 11 along the second direction S. The length of the first exposed portion 11A1 can be, for example, 30% or more and 80% or less of the length of one side of the substrate 11. Figure 3 The exposed portion 11A shown is arranged line-symmetrically with respect to a bisector extending in the first direction F and dividing one side of the substrate 11 into two.

[0062] exist Figure 4 In the light emitting element of another embodiment of the present disclosure shown in the figure, the exposed portion 11A includes a first exposed portion 11A1 extending along the first direction F and a second exposed portion 11A2 arranged at the outer periphery of the quadrilateral substrate 11. The first exposed portion 11A1 extends along the first direction F from the second exposed portion 11A2 located at the midpoint of one side of the quadrilateral substrate 11 along the second direction S. The length of the first exposed portion 11A1 can be, for example, 40% or more and 80% or less of the length of one side of the substrate 11. Figure 4 The exposed portion 11A shown is arranged line-symmetrically with respect to a bisector extending in the first direction F and dividing one side of the substrate 11 into two.

[0063] exist Figure 5 In the light-emitting element used in the light-emitting device of one embodiment of the present disclosure, the exposed portion 11A includes four first exposed portions 11A1 extending along the first direction F or the second direction S and a second exposed portion 11A2 arranged at the outer periphery of the quadrilateral substrate 11. The four first exposed portions 11A1 extend from the second exposed portions 11A2 located at the midpoints of the respective sides of the quadrilateral substrate 11 toward the center of the substrate 11. The length of the first exposed portion 11A1 can be, for example, 5% or more and 45% or less of the length of one side of the substrate 11. Figure 5 The exposed portion 11A shown in FIG. 1 is arranged point-symmetrically with respect to the center of the substrate 11 .

[0064] It should be noted that Figure 3 , 4 The first exposed portion 11A1 shown in FIG. 5 may have a portion that is orthogonal to or intersects the linear portion at an angle of 45° to 135° from the linear portion of the first exposed portion 11A1.

[0065] (p-electrode 16 and n-electrode 17)

[0066] The n-electrode 17 and the p-electrode 16 are arranged on the upper surface side of the semiconductor structure 15 .

[0067] The p-electrode 16 is disposed on the p-side semiconductor layer 14 and is electrically connected to the p-side semiconductor layer 14. When viewed from above, the p-electrode 16 is disposed between the extension portion 17B and the first exposed portion 11A1. Preferably, the p-electrode 16 is disposed on substantially the entire surface of the upper surface of the p-side semiconductor layer 14. Preferably, when viewed from above, the p-electrode 16 surrounds the entire periphery of the first exposed portion 11A1. The width of the p-electrode 16 between the extension portion 17B and the first exposed portion 11A1 is preferably greater than 10 μm, and more preferably greater than 30 μm and less than 200 μm. By having such a width of the p-electrode 16, the current can be efficiently diffused to the p-side semiconductor layer 14.

[0068] A p pad electrode 18 electrically connected to the p electrode 16 is disposed on the upper surface of the p electrode 16. The p pad electrode 18 may be disposed on the entire upper surface of the p electrode 16 or on a portion of the upper surface of the p electrode 16.

[0069] The n-side semiconductor layer 12 of the n-electrode 17 is disposed on the n-layer exposed portion exposed from the active layer 13 and the p-side semiconductor layer 14 , and is electrically connected to the n-side semiconductor layer 12 .

[0070] The n-electrode 17 includes a base portion 17A and a plurality of extension portions 17B extending from the base portion 17A.

[0071] The shape and size of the base 17A can be appropriately set according to the shapes and sizes of the semiconductor structure 15, the first exposed portion 11A1, the second exposed portion 11A2 of the substrate 11, etc. In a plan view, the shape of the base 17A can be various shapes, such as a polygon and a shape with rounded corners.

[0072] The extension portions 17B extend in different directions from different plural positions of the base portion 17A.

[0073] like Figure 1 As shown, the base 17A is located at the center of the semiconductor structure 15 when viewed from above. The extension portion 17B extends linearly from the base 17A toward the four corners of the substrate 11. The extension portion 17B may be a shape having a linear portion, or a shape having a linear portion and a portion extending from the linear portion. The extension direction of the portion extending from a linear portion is not limited to one direction, and may be two directions, or may be three or more directions. In addition, the extension direction of the portion extending from a linear portion may be, for example, a direction inclined at more than 45° and less than 90° relative to a linear shape. Figure 1In the embodiment, an extension portion 17B extending from the base portion 17A has a linear portion and portions extending from the linear portion in two directions orthogonal to the linear portion. Such an extension portion 17B extends from four positions of the base portion 17A. When viewed from above, Figure 1 The n-electrode 17 shown is arranged point-symmetrically with respect to the center of the substrate 11 .

[0074] exist Figure 3 In the light-emitting element of another embodiment of the present disclosure shown, the n-electrode 17 has a base 17A, and the base 17A is arranged at a position adjacent to a side extending along the second direction S. The n-electrode 17 has a plurality of extensions 17B extending linearly from the base 17A along the first direction F. The extensions 17B can be in a shape having a linear portion, or in a shape having a linear portion and a portion extending from a linear portion. For example, the three extensions 17B can include extensions extending parallel to each other from both ends and the central portion of the base 17A. The widths and lengths of the three extensions 17B can be different, but are preferably the same. The n-electrode 17 is arranged in line symmetry with respect to a bisector extending along the first direction F and dividing one side of the substrate 11 into two equal parts.

[0075] exist Figure 4 In the light-emitting element of another embodiment of the present disclosure shown, the n-electrode 17 has a base 17A, and the base 17A is arranged at a position adjacent to a side extending along the second direction S. The n-electrode 17 has a plurality of extensions 17B extending linearly from the base 17A along the first direction F. The extensions 17B can be in a shape having a linear portion, or in a shape having a linear portion and a portion extending from a linear portion. For example, the two extensions 17B can be extensions extending from the two ends of the base 17A in parallel to each other. The widths and lengths of the two extensions 17B can be different, but are preferably the same. The n-electrode 17 is arranged in line symmetry with respect to a bisector extending along the first direction F and dividing one side of the substrate 11 into two equal parts.

[0076] In any of the shapes of the base portion 17A and the extension portion 17B, the first exposed portion 11A1 of the substrate 11 is preferably disposed between at least two extension portions 17B, and more preferably, all of the first exposed portions 11A1 are disposed between the extension portions 17B.

[0077] The n-electrode 17, the p-electrode 16, and the p-pad electrode 18 can be, for example, a single-layer structure or a stacked structure containing metals such as Au, Pt, Pd, Rh, Ru, Ni, W, Mo, Cr, Ti, Al, Cu, Ta, Si, or their alloys. Specifically, the p-electrode 16 can be a stacked structure of Rh / Ni / Au, Ru / Ni / Au, etc. Specifically, the n-electrode 17 and the p-pad electrode 18 can be a stacked structure of Ti / Rh / Au, Ti / Pt / Au, W / Pt / Au, Rh / Pt / Au, Ni / Pt / Au, Ti / Ru / Ti, Ti / Al-Si / Ta / Ru, etc. stacked in sequence from the semiconductor structure 15 side. It should be noted that "Ti / Rh / Au" stacked in sequence from the semiconductor structure 15 side means that Ti, Rh, and Au are stacked in sequence from the semiconductor structure 15 side. The film thicknesses of the n-electrode 17 , the p-electrode 16 , and the p-pad electrode 18 may be any of the film thicknesses of films used in the relevant fields.

[0078] [Light emitting device 20]

[0079] like Figure 6 As shown, a light emitting device 20 according to an embodiment of the present disclosure includes, for example, the above-described light emitting element 10 and a cover member 21 .

[0080] like Figure 5 as well as Figure 6 As shown, the light emitting device 20 has a p-side external connection portion 26 electrically connected to the p-electrode 16 and an n-side external connection portion 27 electrically connected to the n-electrode 17. A portion of the p-side external connection portion 26 and a portion of the n-side external connection portion 27 are exposed from the cover member 21. With such a structure, flip-chip packaging of the light emitting device 20 can be performed.

[0081] In addition, if Figure 7F As shown, the light emitting device 20 may include a light transmissive member 22 disposed on the substrate 11 of the light emitting element. In this case, the side surfaces of the substrate 11 and the side surfaces of the light transmissive member 22 are preferably covered by the covering member 21.

[0082] (Covering member 21)

[0083] The covering member 21 covers at least the side surface of the n-side semiconductor layer 12 and the side surface of the active layer 13 adjacent to the exposed portion 11A. The covering member 21 preferably further covers the side surface of the p-side semiconductor layer 14, and more preferably covers the side surface of the p-side external connection portion 26 and the side surface of the n-side external connection portion 27. In addition, when the light-emitting element 10 is provided with a translucent member 22, it is more preferred that the side surface of the translucent member 22 is also covered by the covering member 21. Here, "covering" includes not only a state in which the covering member 21 is provided in contact with the light-emitting element 10 and / or the translucent member 22, but also a state in which the covering member 21 is provided with another member, a space (e.g., an air layer), etc. between the light-emitting element 10 and / or the translucent member 22. The upper surface of the translucent member 22 exposed from the covering member 21 becomes the light emitting surface of the light-emitting device.

[0084] The cover member 21 can be composed of, for example, a light-transmitting material and a light-absorbing material and / or a reflective material contained therein. The light-transmitting material can be composed of an organic material, an inorganic material, or the like.

[0085] As the organic material, a material containing a light-reflecting substance, a fluorescent substance, a diffusing material, a colorant, etc. in a resin can be used. The resin, the light-reflecting substance, etc. can also use any of the resins, light-reflecting substances, etc. commonly used in this field. For example, as the resin, there can be cited one or more resins or mixed resins including silicone resins, modified silicone resins, epoxy resins, modified epoxy resins, and acrylic resins. As the light-reflecting substance, there can be cited silicon dioxide, titanium oxide, zirconium oxide, potassium titanate, aluminum oxide, aluminum nitride, boron nitride, mullite, etc. The amount of light reflected, the amount of light transmitted, etc. can be changed by the content of the light-reflecting substance, etc. in the material constituting the covering member 21. Preferably, the covering member 21 contains, for example, 20wt% or more of the light-reflecting substance.

[0086] Preferably, the light-transmitting material is an inorganic material, and more preferably, the light-transmitting material and the light-reflecting substance are inorganic materials. That is, preferably, the main component of the covering part 21 is an inorganic material. The main component here means accounting for more than 50% of the total weight of the covering part. In this case, more preferably, the covering part 21 is composed of a plurality of inorganic materials. For example, the covering part 21 can include a covering part including a light-reflecting part and a supporting part supporting the light-reflecting part. Preferably, the supporting part is a supporting part including silicon dioxide and an alkali metal. The covering part 21 may further include a scattering material.

[0087] By using such a covering member 21 to cover the semiconductor structure 15 and the exposed portion 11A of the substrate, the light emitted from the semiconductor structure 15 near the first exposed portion 11A1 can be reflected more efficiently to the light extraction surface side. Thus, a light-emitting device with high light extraction efficiency can be provided. In particular, by arranging the covering member 21 at the first exposed portion 11A1 of the semiconductor structure 15, the light emitted from the semiconductor structure 15 near the first exposed portion 11A1 can be reflected more efficiently to the light extraction surface. In addition, in the case where the covering member 21 is composed only of an inorganic material, even if the light emitted from the light-emitting device 20 is ultraviolet light, the degradation of the covering member 21 can be reduced, and the life of the light-emitting device 20 can be extended.

[0088] (Light reflective parts)

[0089] The light-reflective component can be any light-reflective component that can reflect light from the light-emitting element 10, and examples thereof include ceramics such as boron nitride and aluminum oxide. Preferably, the light-reflective component uses a plate-like or scaly granular light-reflective component. The light-reflective component can be any of primary particles and secondary particles. The average particle size of the light-reflective component can be, for example, a particle size of 0.1 μm or more and 100 μm or less, and preferably a particle size of 0.6 μm or more and 43 μm or less. The average aspect ratio of the particles of the light-reflective component can be, for example, 10 or more, and preferably 10 or more and 70 or less. The average aspect ratio is represented by the ratio of the longest length to the shortest length passing through the center of a particle. Here, the average particle size can be obtained by cross-sectional observation using SEM, by measuring the particle size distribution using a laser diffraction method, and the like.

[0090] When the covering member 21 is heated by the heat generated from the light emitting element 10, the light reflective member having such an average particle size and average aspect ratio functions as a frame material of the covering member 21. As a result, the shrinkage of the covering member 21 caused by the heat of the light emitting element 10 is suppressed, and a light emitting device with high heat resistance can be obtained. The service life of such a light emitting device is prolonged. In addition, the covering member 21 can reflect the light from the light emitting element by utilizing the refractive index difference between the light reflective member and the supporting member. Furthermore, by obtaining the covering member 21 in which the shrinkage caused by the heat of the light emitting element 10 is suppressed, the light emitting device can be used even under conditions where the heat generated from the light emitting element is large (for example, when the electric power supplied to the light emitting element is large). In addition, by being able to increase the electric power supplied to the light emitting element, the brightness of each light emitting device can be increased.

[0091] (Supporting parts)

[0092] The supporting member is a member for supporting the light-reflecting member included in the covering member 21 so as to improve the strength of the covering member 21. The content ratio of the supporting member and the light-reflecting member included in the covering member 21 can be, for example, 1:4 or more and 1:1 or less in terms of weight ratio. By setting it to this range, the shrinkage when the covering member is cured can be reduced. In the case of using silica as the supporting member, the average particle size of the silica can be, for example, 0.1 μm or more and 10 μm or less. If it is within this range, the density per unit volume of the light-reflecting member and the supporting member can be increased, and the strength of the covering member can be improved. Preferably, the average particle size of the silica powder is smaller than the average particle size of the light-reflecting member. Thus, the silica powder used as the supporting member can fill the gaps formed between the light-reflecting members when mixed. The average particle size of the powder of the supporting member is a value measured before mixing with the solution containing the alkali metal. In order to calculate the content ratio of the supporting member and the light reflecting member from the covering member, for example, a cross section of the covering member extracted by SEM can be observed and the content ratio of the supporting member and the light reflecting member can be calculated based on the occupancy rate of the supporting member and the light reflecting member.

[0093] Examples of the alkali metal include potassium and sodium. Preferably, the alkali metal is mixed with the silica in a solution state.

[0094] Scattering materials include, for example, zirconium oxide, titanium dioxide, materials obtained by surface treatment of these materials with silicon dioxide, aluminum oxide, zirconium oxide, zinc, organic matter, etc., stabilized zirconium oxide or partially stabilized zirconium oxide added with calcium, magnesium, yttrium, aluminum, etc. In the case where the light-emitting element emits ultraviolet light, it is preferred to use zirconium oxide with less light absorption in the ultraviolet wavelength region as a scattering agent. By including the scattering material in the covering member 21, the light reflectivity of the covering member 21 is improved. Preferably, the scattering material has an average particle size smaller than the average particle size of the light-reflecting member. Thus, when gaps are generated between the light-reflecting members, the scattering material is easily arranged in the gaps, thereby suppressing the light emitted from the light-emitting element 10 from being emitted to the outside of the light-emitting device through the gaps between the light-reflecting members. As a result, the light extraction efficiency of the light-emitting device can be improved. The average particle size of the scattering material can be measured by a laser diffraction method. In the case where the scattering material is added to the covering member 21, it is preferred that the scattering material is dispersed in the supporting member.

[0095] Preferably, the linear thermal expansion coefficient of the cover member 21 is 0.5 ppm / ° C. to 5 ppm / ° C. in the temperature range of 40° C. to 300° C. Thus, even if the temperature of the cover member 21 rises when the light emitting device is used, expansion of the cover member 21 can be suppressed.

[0096] (p-side external connection portion 26 and n-side external connection portion 27)

[0097] The p-side external connection portion 26 is electrically connected to the p-electrode 16, and the n-side external connection portion 27 is electrically connected to the n-electrode 17. When the light emitting device 20 is mounted, the p-side external connection portion 26 and the n-side external connection portion 27 are electrically connected to, for example, conductive wiring or the like. The p-side external connection portion 26 and the n-side external connection portion 27 can be respectively arranged in a region that divides the area of ​​the semiconductor structure 15 into two equal parts, for example, when viewed from above. In this case, it is preferable that they are arranged in line symmetry with respect to a bisector that divides the area of ​​the semiconductor structure 15 into two equal parts when viewed from above. The p-side external connection portion 26 and the n-side external connection portion 27 are respectively arranged above the n-side semiconductor layer 12 and the p-side semiconductor layer 14 via the insulating film 25.

[0098] The size, shape, etc. of the p-side external connecting portion 26 and the n-side external connecting portion 27 can be appropriately set according to the desired performance of the light emitting device.

[0099] The p-side external connection portion 26 and the n-side external connection portion 27 can be made of metals such as Cu, Au, Ni, or alloys containing these metals in a single-layer structure or a stacked structure. The thickness of the p-side external connection portion 26 and the n-side external connection portion 27 can be, for example, 1 μm or more and 50 μm or less, preferably 10 μm or more and 30 μm or less.

[0100] (Insulating film 25)

[0101] The insulating film 25 covers the upper surface and side surfaces of the semiconductor structure 15. The insulating film 25 has a p-side opening 25p above the p-electrode 16 in a region where the p-side external connection portion 26 is arranged, and has an n-side opening 25n above the n-electrode 17 in a region where the n-side external connection portion 27 is arranged. Figure 5 In the example shown, the n-side opening 25n is arranged in a region overlapping with the extension 17B of the n-electrode 17. The p-side external connection portion 26 is electrically connected to the p-electrode 16 at the p-side opening 25p. The n-side external connection portion 27 is electrically connected to the n-electrode 17 at the n-side opening 25n. In the case where the insulating film 25 covers the upper surface of the semiconductor structure 15 in this way, the n-side external connection portion 27 can be arranged on the upper surface of the insulating film 25 covering the upper surface of the p-side semiconductor layer 14. Similarly, in the case where the insulating film 25 covers the upper surface of the semiconductor structure 15, the p-side external connection portion 26 can be arranged on the upper surface of the insulating film 25 covering the upper surface of the n-side semiconductor layer 12.

[0102] Preferably, the insulating film 25 is made of a material known in the art, and has a material and thickness having light transmittance and electrical insulation. Specifically, the insulating film 25 can be made of metal oxides and metal nitrides, for example, at least one oxide or nitride selected from the group consisting of Si, Ti, Zr, Nb, Ta, and Al. The insulating film may be any insulating film as long as it has a film thickness that can obtain light transmittance and insulation.

[0103] (Light-transmitting member 22)

[0104] Preferably, the light-emitting device has a translucent component 22 on the substrate 11 of the light-emitting element 10. The translucent component 22 is arranged to cover the light extraction surface of the light-emitting element 10. The translucent component 22 is a component that can transmit more than 50% or more than 60%, preferably more than 70%, of the light emitted from the light-emitting element 10 and release it to the outside. The translucent component 22 can contain a phosphor that can convert the wavelength of at least a part of the light emitted from the light-emitting element 10. In addition, the translucent component 22 may also contain a light diffusing material that diffuses the light emitted from the light-emitting element 10. The translucent component 22 is preferably in a plate shape, and the thickness of the translucent component 22 can be, for example, more than 50 μm and less than 300 μm.

[0105] The light-transmitting component 22 can be made of, for example, resin, glass, inorganic material, etc. Examples of the light-transmitting component 22 containing a phosphor include a sintered body obtained by sintering a phosphor, a light-transmitting component obtained by containing a phosphor in a resin, glass, or other inorganic material, etc. It can also be a light-transmitting component in which a resin layer containing a phosphor is formed on a flat-plate-shaped molded body of resin, glass, or inorganic material. If the light-transmitting component 22 is an inorganic material, since the heat resistance is higher than that of a light-transmitting component containing a resin, a light-emitting device with high heat resistance can be produced. When the light-transmitting component 22 does not contain a wavelength conversion material, the light from the light-emitting element is emitted to the outside without performing wavelength conversion.

[0106] As the phosphor to be contained in the light-transmitting member 22, a yttrium aluminum garnet-based phosphor (for example, Y3(Al, Ga)5O 12 :Ce), lutetium aluminum garnet-based phosphors (such as Lu3(Al, Ga)5O 12 :Ce), terbium aluminum garnet-based phosphors (such as Tb3(Al, Ga)5O 12 :Ce), CCA-based phosphors (such as Ca 10 (PO4)6Cl2:Eu), SAE-based phosphors (such as Sr4Al 14 O 25 :Eu), chlorosilicate-based phosphors (e.g. Ca8MgSi4O 16Cl2:Eu), oxynitride-based phosphors, nitride-based phosphors, fluoride-based phosphors, phosphors with a perovskite structure (e.g. CsPb(F, Cl, Br, I)3), quantum dot phosphors (e.g. CdSe, InP, AgInS2 or AgInSe2), etc. Examples of oxynitride-based phosphors are β-Sialon-based phosphors (e.g. (Si, Al)3(O, N)4:Eu), α-Sialon-based phosphors (e.g. Ca(Si, Al) 12 (O, N) 16 Examples of nitride-based phosphors include SLA-based phosphors (e.g., SrLiAl3N4:Eu), CASN-based phosphors (e.g., CaAlSiN3:Eu), and SCASN-based phosphors (e.g., (Sr, Ca)AlSiN3:Eu). Examples of fluoride-based phosphors include KSF-based phosphors (e.g., K2SiF6:Mn), KSAF-based phosphors (e.g., K2Si 0.99 Al 0.01 F 5.99 :Mn) and MGF-based phosphors (e.g. 3.5MgO·0.5MgF2·GeO2:Mn) etc. By combining these phosphors with a blue light emitting element or an ultraviolet light emitting element, a light emitting device with a desired light emitting color can be obtained. When such a phosphor is contained in the light-transmitting member 22, the content of the phosphor is preferably set to, for example, 5wt% or more and 50wt% or less.

[0107] The light-transmitting member 22 is arranged to cover the light extraction surface of the light-emitting element 10. The light-transmitting member 22 and the light-emitting element 10 may be bonded via an adhesive material or by a direct bonding method. The adhesive material may be an adhesive material using a light-transmitting resin material such as epoxy resin or silicone resin.

[0108] For the purpose of protecting the light-transmitting member 22 and suppressing light reflection, a cover layer may be disposed on the upper surface of the light-transmitting member 22. Examples of the cover layer include an AR (Anti Reflection) layer and the like.

[0109] [Method for manufacturing light emitting device]

[0110] The above-mentioned light emitting device can be manufactured by the following steps:

[0111] Preparing a light emitting element 10;

[0112] Preparing a sheet-shaped covering member 21A;

[0113] For the light emitting element 10 , a cover member 21A is disposed on the side of the substrate 11 where the semiconductor structure 15 is disposed;

[0114] The cover member 21A is formed while applying vibration to the side surface of the semiconductor structure 15 of the light emitting element 10 .

[0115] Preferably, the covering member 21 is heated and cured after being arranged on the side surface of the light-emitting element 10. Preferably, the curing is performed in two stages, namely, pre-curing and formal curing. Thus, the occurrence of cracks toward the formed covering member 21 can be suppressed. Pre-curing can be performed, for example, at a temperature of 80°C to 100°C for 10 minutes to 2 hours. Formal curing can be performed, for example, at a temperature of 150°C to 250°C for 10 minutes to 3 hours. In addition, preferably, these curings are performed while pressurizing. The pressure applied in this case can be, for example, 0.5 MPa to 5 MPa, for example, 1 MPa. Thus, since the light-reflective components in the covering member are cured in a more densely arranged state, the light reflectivity of the formed covering member 21 can be improved. It should be noted that the pressure applied during pre-curing and formal curing can be the same or different.

[0116] Only one light emitting element 10 may be prepared, or a plurality of light emitting elements 10 may be prepared to form a plurality of light emitting devices in batches, and then divided into individual light emitting devices 20 after the cover member 21A is formed.

[0117] First, if Fig. 7A As shown in FIG. 1 , a sheet-shaped covering member 21A is prepared.

[0118] The sheet-shaped covering member 21A can be formed, for example, as follows.

[0119] The mixture is prepared by mixing powder of the light reflective component, powder of silicon dioxide as a supporting component, and an alkaline solution. A scattering material may also be mixed in the mixture. After the mixture is mixed to a uniform viscosity, it is degassed and stirred by a stirring degassing machine capable of decompression and stirring. Thereafter, the mixture is coated on a substrate 32 having peelability to form a sheet.

[0120] In addition, if Figure 7B As shown, a plurality of light emitting elements 10 are prepared with a light transmissive member 22 disposed on the upper surface. The light transmissive member 22 contains a phosphor. When the light transmissive member 22 is bonded to the light emitting element 10, a direct bonding method such as surface activation bonding, atomic diffusion bonding, or hydroxyl bonding can be used. Preferably, the plurality of light emitting elements 10 are arranged at a predetermined interval, and the light transmissive member 22 is bonded to the adhesive sheet 31.

[0121] Then, if Figure 7CAs shown, by covering the side of the light emitting element 10 where the p-side external connection portion 26 and the n-side external connection portion 27 are arranged and pressing the sheet-shaped covering member 21A, the covering member 21A is pushed in and arranged on the side of the light emitting element 10. The p-side external connection portion 26 and the n-side external connection portion 27 of the light emitting element 10 are covered by the covering member 21A. At this time, by connecting the first exposed portion 11A1 and the second exposed portion 11A2, the covering member 21A can be easily arranged on the side of the semiconductor structure 15 adjacent to the first exposed portion 11A1. In addition, when forming the covering member 21A, by forming the covering member 21A while applying vibration, the covering member 21A can be made fluid, and the covering member 21A can be more easily formed on the side of the light emitting element 10. In addition, when forming the covering member 21A, by forming it in a vacuum state, it is possible to suppress the generation of a gap between the light emitting element 10 and the covering member 21A.

[0122] Thereafter, for example, 1 MPa is applied to the cover member 21A at 90° C. to pre-cure it. Fig.7D As shown, the base 32 is removed from the cover member 21A. Furthermore, a load of 1 MPa is applied to the cover member 21A at 200° C. to fully cure the cover member 21A, and the adhesive sheet 31 is removed from the light emitting element.

[0123] Next, if Fig. 7E As shown in FIG. 1 , the cover member 21A is polished so that the upper surfaces of the p-side external connection portion 26 and the n-side external connection portion 27 are exposed from the cover member 21A. Next, the cover member 21A located between the light emitting elements 10 can be cut to obtain Figure 7F The light emitting device 20 shown. The covering member 21A can be cut using a blade 33, for example.

[0124] According to the manufacturing method of the light emitting device, a light emitting device can be efficiently manufactured in which the light extraction efficiency from the side surface of the semiconductor structure 15 adjacent to the first exposed portion 11A1 is improved. In particular, by connecting the first exposed portion 11A1 and the second exposed portion 11A2 of the substrate 11, it is easy to arrange the cover member 21 on the side surface of the semiconductor structure 15. As a result, the light emitted from the side surface of the semiconductor structure 15 can be efficiently reflected to the light extraction surface side, and a light emitting device with further improved brightness can be obtained.

[0125] This specification includes the following embodiments.

[0126] 1. A light emitting element, comprising:

[0127] substrate;

[0128] A semiconductor structure, which is arranged on the substrate and includes, in order from the substrate side, an n-side semiconductor layer, an active layer and a p-side semiconductor layer;

[0129] A p-electrode, which is disposed on the p-side semiconductor layer and is electrically connected to the p-side semiconductor layer;

[0130] An n-electrode is disposed on the n-side semiconductor layer and is electrically connected to the n-side semiconductor layer;

[0131] The n-electrode includes a base portion and a plurality of extension portions extending from the base portion,

[0132] The substrate includes an exposed portion exposed from the semiconductor structure.

[0133] In a plan view, the exposed portion includes: a first exposed portion located between two adjacent extending portions; a second exposed portion disposed at the outer periphery of the substrate and connected to the first exposed portion;

[0134] The p-electrode is arranged between the extending portion and the first exposed portion in a plan view.

[0135] 2. The light-emitting element according to 1 above,

[0136] The n-electrode includes three or more extensions,

[0137] The first exposed portions are respectively arranged between the plurality of extending portions.

[0138] 3. In the light emitting element described in 1 or 2 above, the second exposed portion surrounds the semiconductor structure in a plan view.

[0139] 4. The light-emitting element according to any one of 1 to 3 above, wherein the number of the semiconductor structure is one.

[0140] 5. In the light emitting element described in any one of 1 to 4 above, the active layer and the n-side semiconductor layer include a semiconductor layer made of AlGaN having an Al composition ratio of 30% or more.

[0141] 6. In the light-emitting element according to any one of 1 to 5 above, a peak wavelength of light emitted from the active layer is not less than 250 nm and not more than 330 nm.

[0142] 7. A light emitting device, comprising:

[0143] The light-emitting element as described in any one of 1 to 6 above;

[0144] A covering member covers at least the side surface of the n-side semiconductor layer and the side surface of the active layer adjacent to the exposed portion in a plan view.

[0145] 8. In the light-emitting device described in item 7 above, a main component of the covering member is an inorganic material.

[0146] Description of Reference Numerals

[0147] 10 Light-emitting elements

[0148] 11. Substrate

[0149] 11A, exposed part

[0150] 11A1, first exposed part

[0151] 11A2, second exposed part

[0152] 12. n-side semiconductor layer

[0153] 13. Active layer

[0154] 14. P-side semiconductor layer

[0155] 15. Semiconductor structures

[0156] 16. p-electrode

[0157] 17. n-electrode

[0158] 17A, base

[0159] 17B, ​​extension

[0160] 18. p pad electrode

[0161] 20. Light-emitting device

[0162] 21. 21A. Covering parts

[0163] 22. Translucent parts

[0164] 25. Insulation film

[0165] 25n, n side opening

[0166] 25p, p side opening

[0167] 26. P-side external connection

[0168] 27. External connection on the n side

[0169] 31. Adhesive sheet

[0170] 32. Matrix

[0171] 33. Blade

Claims

1. A light emitting element, characterized in that: include: substrate; A semiconductor structure, which is arranged on the substrate and includes, in order from the substrate side, an n-side semiconductor layer, an active layer and a p-side semiconductor layer; A p-electrode, which is disposed on the p-side semiconductor layer and is electrically connected to the p-side semiconductor layer; An n-electrode is disposed on the n-side semiconductor layer and is electrically connected to the n-side semiconductor layer; The n-electrode includes a base portion and a plurality of extension portions extending from the base portion, The substrate includes an exposed portion exposed from the semiconductor structure. In a plan view, the exposed portion includes: a first exposed portion located between two adjacent extending portions; a second exposed portion disposed at the outer periphery of the substrate and connected to the first exposed portion; The p-electrode is arranged between the extending portion and the first exposed portion in a plan view.

2. The light emitting element according to claim 1, wherein The n-electrode includes three or more extensions, The first exposed portions are respectively arranged between the plurality of extending portions.

3. The light emitting element according to claim 1 or 2, characterized in that: In a plan view, the second exposed portion surrounds the semiconductor structure.

4. The light-emitting element according to any one of claims 1 to 3, characterized in that The semiconductor structure is one.

5. The light emitting element according to any one of claims 1 to 4, characterized in that The active layer and the n-side semiconductor layer include a semiconductor layer made of AlGaN having an Al composition ratio of 30% or more.

6. The light emitting element according to any one of claims 1 to 5, wherein The peak wavelength of light emitted from the active layer is greater than or equal to 250 nm and less than or equal to 330 nm.

7. A light emitting device, characterized in that: include: The light-emitting element according to any one of claims 1 to 6; A covering member covers at least the side surface of the n-side semiconductor layer and the side surface of the active layer adjacent to the exposed portion in a plan view.

8. The light emitting device according to claim 7, characterized in that: The main component of the covering member is an inorganic material.

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