Semiconductor light emitting element and semiconductor light emitting device

Abstract

To provide a semiconductor light-emitting element and device that can achieve uniform current injection, uniform light emission, and a high light-emission efficiency.SOLUTION: A semiconductor light-emitting element comprises: a light-emitting function layer 15M configured by laminating on an insulative substrate 11 a first semiconductor layer 12 of a first polarity, a light-emitting layer 13, and a second semiconductor layer 14 of a second polarity; a first electrode layer 22 on the first semiconductor layer; a second electrode layer 23 on the second semiconductor layer; a first insulating layer 25 that covers the light-emitting function layer while exposing a part of the first and second electrode layers; a coating metal layer 26 that covers the light-emitting function layer, and are connected with the first electrode layer; a second insulating layer 27 that covers the coating metal layer; a first pad electrode 28A connected with the first electrode layer, and covering the light-emitting function layer and the first and second insulating layers; and a second pad electrode 28B connected with the coating electrode layer, and covering the light-emitting function layer and the first and second insulating layers. The light-emitting function layer has a pair of sides opposed to each other and has a pair of connection parts where the first semiconductor layer is exposed along the pair of sides. The first electrode layer is in Schottky contact with the pair of connection parts of the first semiconductor layer.SELECTED DRAWING: Figure 1B

Description

[Technical Field]

[0001] The present invention relates to a semiconductor light emitting element and a semiconductor light emitting device, and more particularly to a semiconductor light emitting element such as a light emitting diode (LED) and a semiconductor light emitting device having the semiconductor light emitting element. [Background technology]

[0002] In recent years, semiconductor light-emitting elements such as light-emitting diodes (LEDs) have been arranged and used in multiple devices in order to achieve higher output and light distribution control.

[0003] For example, adaptive driving beam (ADB) headlamps are known for their variable light distribution, which controls the light distribution according to the driving environment. Also known are high-power LED packages for lighting and LED packages for information and communication devices with high-density LED arrangements.

[0004] However, there is an increasing demand for high-power semiconductor light-emitting elements that have high luminous efficiency and can emit uniform light. There is also a demand for semiconductor light-emitting devices that are less susceptible to element breakdown by providing additional functions such as a protective element while preventing performance degradation of the light-emitting element.

[0005] For example, Patent Document 1 describes a light-emitting device having a plurality of holes that penetrate an active layer and expose a first semiconductor layer, and a first solder pad and a second solder pad formed in an area other than the positions of the plurality of holes, which aims to equalize the light field distribution and reduce the forward voltage of the light-emitting device.

[0006] Patent document 2 also describes a light-emitting element structure that includes multiple semiconductor stacks including multiple grooves and a flat base with an upper surface, and an electrode is provided on a first semiconductor layer exposed from the bottom of the multiple grooves.

[0007] Furthermore, Patent Document 3 discloses a semiconductor light-emitting element having a mesa structure, which prevents a decrease in light-emitting efficiency by preventing the current flowing between the p-electrode and the n-electrode from concentrating in the region near the mesa edge.

[0008] Also, Non-Patent Document 1 discloses lateral current crowding in GaN-based LEDs grown on sapphire. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2017-92477 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-150188 [Patent Document 3] Japanese Patent Application Publication No. 2017-28032 [Non-patent literature]

[0010] [Non-Patent Document 1] “Current crowding in GaN / InGaN light emitting diodes on insulating substrates”, X. Guo et al., J. Appl. Phys.,Vol. 90, No.8, 15 October 2001 Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a semiconductor light emitting element and a semiconductor light emitting device that can obtain uniform current injection and light emission and have high light emitting efficiency. [Means for solving the problem]

[0012] A semiconductor light emitting device according to one embodiment of the present invention comprises: an insulating or semi-insulating substrate; a light-emitting functional layer in which a first semiconductor layer of a first polarity, a light-emitting layer, and a second semiconductor layer of a second polarity are sequentially stacked on the substrate; a first electrode layer provided on the first semiconductor layer of the light-emitting functional layer; a second electrode layer provided on the second semiconductor layer of the light-emitting functional layer; a first insulating layer that covers the light-emitting functional layer and exposes a portion of the first electrode layer and the second electrode layer; a covering metal layer that covers the light-emitting functional layer and is connected to the first electrode layer; a second insulating layer covering the covering metal layer; a first pad electrode connected to the first electrode layer and covering the light-emitting function layer and the first and second insulating layers; a second pad electrode connected to the covering electrode layer and covering the light-emitting function layer and the first and second insulating layers, the light-emitting functional layer has a pair of sides facing each other and a pair of connection portions along the pair of sides at which the first semiconductor layer is exposed, The first electrode layer is in Schottky contact with the pair of connection portions of the first semiconductor layer.

[0013] A semiconductor light emitting device according to another embodiment of the present invention includes: a light emitting element assembly including the semiconductor light emitting element and a light guiding member bonded to the semiconductor light emitting element by an adhesive layer; a light-shielding layer made of an inorganic material that is a light reflector covering a side surface of the light-emitting element assembly; It has the following characteristics. [Brief explanation of the drawings]

[0014] [Figure 1A] 1 is a top view schematically showing a semiconductor light emitting device 10 according to a first embodiment of the present invention as viewed from above. [Figure 1B] FIG. 1B is a cross-sectional view schematically showing a cross section taken along line AA in FIG. 1A. [Figure 2A] 2 is a top view schematically showing the top surface of the semiconductor light emitting element 10. FIG. [Figure 2B]2B is a partially enlarged cross-sectional view showing a cross section of an end portion of the semiconductor light-emitting element 10 taken along line BB in FIG. 2A. [Figure 2C] 2B is a partially enlarged cross-sectional view showing a cross section of an end portion of the semiconductor light-emitting element 10 taken along line CC in FIG. 2A. [Figure 2D] 2B is a partially enlarged cross-sectional view showing a cross section of an end portion of the semiconductor light-emitting element 10 taken along line DD in FIG. 2A. [Figure 2E] 2B is a partially enlarged cross-sectional view showing a cross section of an end portion of the semiconductor light-emitting element 10 taken along line EE in FIG. 2A. [Figure 3] FIG. 2 is a top view schematically showing a Schottky contact portion and an ohmic contact portion. [Figure 4A] 2A to 2C are cross-sectional views showing steps in a method for manufacturing the semiconductor light-emitting element 10. [Figure 4B] 2A to 2C are cross-sectional views showing steps in a method for manufacturing the semiconductor light-emitting element 10. [Figure 4C] 2A to 2C are cross-sectional views showing steps in a method for manufacturing the semiconductor light-emitting element 10. [Figure 5A] 1 is a perspective view showing a method for mounting the semiconductor light emitting element 10 on a circuit board. [Figure 5B] FIG. 10 is a perspective view for explaining the discharge of flux that has evaporated during reflow. [Figure 5C] FIG. 5B is a cross-sectional view showing a cross section along line DD in FIG. 5A. [Figure 6] FIG. 1 is a top view showing a semiconductor light emitting device 10A which is a modified example of the first embodiment of the present invention. [Figure 7] FIG. 4 is a cross-sectional view schematically showing a cross section of a semiconductor light-emitting device 50 according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] In the following, preferred embodiments of the present invention will be described, but these may be modified and combined as appropriate. In the following description and accompanying drawings, substantially the same or equivalent parts are designated by the same reference numerals.

[0016] [First embodiment] (1) Structure of semiconductor light emitting element FIG. 1A is a top view schematically showing a semiconductor light emitting element 10 according to a first embodiment of the present invention as viewed from above (also referred to as a top view). For ease of explanation and understanding, the internal structure of electrodes and the like is also shown. FIG. 1B is a cross-sectional view schematically showing a cross section taken along line AA in FIG. 1A. The structure of the semiconductor light emitting element 10 will be described in detail below.

[0017] 1A, the semiconductor light emitting element 10 has a quadrangular prism shape with four mutually perpendicular side surfaces (side surfaces along the x and y directions). The semiconductor light emitting element 10 also has a plurality of light emitting functional portions 15M, which are light emitting regions separated from each other by grooves 15G.

[0018] In this specification, the plurality of light-emitting functional sections 15M and the separation grooves are collectively referred to as the light-emitting functional layer 15. The plurality of light-emitting functional sections 15M extend in a direction (y direction) perpendicular to a pair of opposing sides SF1 and SF3 of the light-emitting functional layer 15. In other words, the plurality of light-emitting functional sections 15M extend parallel to a pair of sides SF2 and SF4.

[0019] 1B, the semiconductor light emitting element 10 has a light-transmitting insulating substrate 11. The substrate 11 may be made of sapphire, AlN (aluminum nitride), or the like.

[0020] Alternatively, the substrate 11 may be formed of an insulating substrate, a semi-insulating or high-resistance material, etc. In this specification, a semi-insulating substrate includes a semiconductor substrate such as a high-resistance GaN substrate. Specifically, it refers to a material that exhibits a high resistance of 1 MΩ / □ or more.

[0021] An n-type semiconductor layer 12 (first semiconductor layer), a light emitting layer 13, and a p-type semiconductor layer 14 (second semiconductor layer) are stacked in this order on a substrate 11, forming a mesa-shaped light emitting function section 15M.

[0022] The mesa-shaped light-emitting functional portion 15M is made of a GaN-based semiconductor layer and can be formed by, for example, MOCVD (metal organic chemical vapor deposition). Note that the crystal growth method is not limited to MOCVD, and MBE (molecular beam epitaxy) and other methods can also be used.

[0023] The n-type semiconductor layer 12 is exposed at the bottom of the grooves 15G between the light-emitting functional sections 15M. An n-electrode 21A is formed on each of the n-type semiconductor layers 12 exposed at the bottom of the plurality of grooves 15G. As shown in FIG. 1A, the plurality of n-electrodes 21A extend along the light-emitting functional sections 15M and are formed in the shape of strips parallel to the light-emitting functional sections 15M.

[0024] The n-electrode 21A is formed as an ohmic electrode in which Ti and Al are formed in this order on the n-type semiconductor layer 12. Note that the n-electrode 21A is not limited to a Ti / Al layer, and may be formed of a material that forms ohmic contact with the n-type semiconductor layer 12, such as Ti / Rh or Ti / Au.

[0025] Auxiliary wiring 21B is formed on n-electrode 21A and along n-electrode 21A. Auxiliary wiring 21B is formed as wiring made of Ni, Au, Ti, and Pt, in this order. Note that n-electrode 21A and auxiliary wiring 21B are collectively referred to as first electrode layer 22.

[0026] The auxiliary wiring 21B is made of a material that forms a Schottky barrier when it comes into contact with the n-type semiconductor layer 12. The auxiliary wiring 21B is not limited to a Ni / Au / Ti / Pt layer. For example, Pd or Rh can be used instead of Pt. Also, a Ni, Ti, or W layer can be provided on top of Pt.

[0027] A p-electrode 23 (second electrode layer) consisting of an ohmic electrode, a reflective layer, and a protective layer is formed in a strip shape on the p-type semiconductor layer 14 on the mesa of the light-emitting functional section 15M. Specifically, an ITO (indium tin oxide) film is formed as the ohmic electrode, and Ni / Ag / Ti / Au layers are formed as the reflective layer and the protective layer.

[0028] The sidewalls and upper surfaces of the mesa-shaped light-emitting functional portion 15M and the p-electrode 23 are covered and protected by a first insulating film 25 made of SiO 2. On the first insulating film 25, a covering metal layer 26 is formed.

[0029] The covering metal layer 26 is a light-reflective n-wiring layer, and is formed so as to cover the sidewalls and upper surface of the light-emitting function portion 15M via the first insulating film 25. The covering metal layer 26 is also electrically connected to the auxiliary wiring 21B and the n-electrode 21A via the opening of the first insulating film 25.

[0030] Specifically, the coating metal layer 26 is formed of a Ni / Al / Ti / Pt layer or a Ti / Al / Ti / Pt layer, but is not limited to these. For example, Pd or Rh can be used instead of Pt. Also, a Ti, Ni, or W layer can be provided on top of Pt.

[0031] The metal coating layer 26 is covered and insulated by a second insulating film 27 made of SiO 2 formed on the metal coating layer 26 .

[0032] 1A, two pad electrodes, i.e., a first pad electrode 28A and a second pad electrode 28B, spaced apart in the extension direction (y direction) of the light-emitting function portion 15M are formed on the second insulating film 27. Specifically, the first pad electrode 28A is formed on one side (referred to as a first region RC1) of a center line CL perpendicular to the extension direction of the light-emitting function portion 15M, and the second pad electrode 28B is formed on the other side (referred to as a second region RC2) spaced apart from the first pad electrode 28A.

[0033] The first pad electrode 28A and the second pad electrode 28B are used as an anode electrode and a cathode electrode, respectively, when the semiconductor light emitting element 10 is mounted on a circuit board or the like.

[0034] 1B, the first pad electrode 28A (anode electrode) is electrically connected to the p-electrode 23 through the opening in the second insulating film 27 and the first insulating film 25, and a p-electrode connection portion 23C is formed. Also, as shown in FIG. 1A, the opening in the first insulating film 25 is provided in the region on one side of the center line CL.

[0035] Further, second pad electrode 28B (cathode electrode) is electrically connected to first electrode 22 consisting of auxiliary wiring 21B and n-electrode 21A via covering metal layer 26 exposed in the opening of second insulating film 27 at the bottom of groove 15G, and n-electrode connecting portion 22C (first electrode connecting portion) is formed. As shown in FIG. 1A, the opening of second insulating film 27 is provided in the region on the other side of center line CL.

[0036] The first pad electrode 28A and the second pad electrode 28B are preferably spaced apart at a constant linear interval DG that is perpendicular to the extending direction (y direction) of the light-emitting function portion 15M. Note that, although the present embodiment shows a case where the first pad electrode 28A and the second pad electrode 28B are rectangular in top view, the present invention is not limited to this.

[0037] A part of the light emitted from the light-emitting functional portion 15M is emitted as direct light Ld from the light-emitting surface 11E of the light-transmitting substrate 11, and a part of the light is emitted as reflected light Lr by the p-electrode 23 from the light-emitting surface 11E.

[0038] (2) Connection structure between the first semiconductor and the electrode Next, the electrical connection between the covering metal layer 26 and the n-electrode 21A and auxiliary wiring 21B at the end of the semiconductor light emitting element 10 will be described with reference to Figures 2A and 2B to 2E. Figure 2A is a top view schematically showing the top surface of the semiconductor light emitting element 10. For ease of explanation and understanding, the internal structure of the electrodes, etc. is also shown.

[0039] 2B to 2E are partially enlarged cross-sectional views showing the cross sections of the end portions of the semiconductor light emitting element 10 taken along lines BB, CC, DD, and EE in FIG. 2A, respectively.

[0040] 2B shows a cross section of the edge portion (first region RC1) of the semiconductor light emitting element 10 along line BB that intersects with the first pad electrode 28A. At the edge portion along side SF4 of the semiconductor light emitting element 10, the n-electrode 21A is formed so as to cover the end portion of the n-type semiconductor layer 12, i.e., so as to cover the side and top surfaces of the end portion.

[0041] This structure prevents current from concentrating at the end of the n-type semiconductor layer 12, which would cause the light-emitting functional section 15M to deteriorate and reduce the light output.

[0042] Additionally, the covering metal layer 26, which is an n-type wiring layer, is in contact with the auxiliary wiring 21B and is formed so as to cover the sides of the light-emitting functional unit 15M. This structure not only protects the light-emitting functional unit 15M, but also functions to reflect light emitted from the light-emitting functional unit 15M toward the light-emitting surface 11E of the substrate 11, thereby increasing the light output.

[0043] 2C, the cross section of the edge portion (second region RC2) of the semiconductor light emitting element 10 taken along a line intersecting the second pad electrode 28B also has a structure similar to that shown in FIG. 2B. That is, at the edge portion along the side SF4 of the semiconductor light emitting element 10, the n-electrode 21A is formed so as to cover the end portion of the n-type semiconductor layer 12. The n-electrode 21A is in ohmic contact with the n-type semiconductor layer 12.

[0044] Therefore, as shown in Figure 3, a connection portion is provided along the side SF4 of the semiconductor light-emitting element 10 that is along the extension direction of the light-emitting functional portion 15M, where the p-type semiconductor layer 14 and the light-emitting layer 13 are removed to expose the n-type semiconductor layer 12, and an n-electrode 21A is connected to the connection portion to form an ohmic connection portion OC1.

[0045] This structure suppresses current concentration along the entire edge portion along side SF4 in the extension direction of the light-emitting function portion 15M (hereinafter simply referred to as side SF4, the same applies below), and prevents deterioration of the light-emitting function portion 15M.

[0046] The above has described side SF4 of semiconductor light emitting element 10, but the edge portion along side SF2 opposite side SF4 also has a similar structure. That is, along side SF2 of semiconductor light emitting element 10, p-type semiconductor layer 14 and light emitting layer 13 have been removed to provide a connection portion where n-type semiconductor layer 12 is exposed, and n-electrode 21A is connected to this connection portion to form ohmic connection portion OC2. In addition, n-electrode 21A is formed so as to cover the end portion of n-type semiconductor layer 12.

[0047] 2D shows a cross section of the semiconductor light emitting element 10 along a side SF1 (x direction) perpendicular to the extension direction (y direction) of the light emitting function portion 15M. On the side SF1, the n-electrode 21A is not provided on the n-type semiconductor layer 12, and the auxiliary wiring 21B is in direct contact with the exposed n-type semiconductor layer 12.

[0048] As described above, the auxiliary wiring 21B is made of a material that forms a Schottky barrier when it comes into contact with the n-type semiconductor layer 12, and the auxiliary wiring 21B forms a Schottky contact with the n-type semiconductor layer 12. In addition, the auxiliary wiring 21B is electrically connected to the covering metal layer 26.

[0049] 3, a Schottky contact connection (Schottky connection) SC1 is formed along the side SF1 of the semiconductor light emitting element 10. The Schottky connection SC1 can prevent current from concentrating at the end of the light emitting functional unit 15M, thereby preventing the crystal layer of the light emitting functional unit 15M from deteriorating and the light output from decreasing.

[0050] The same is true for side SF3 opposite side SF1, as shown in Fig. 2E. Therefore, as shown in Fig. 3, a Schottky junction SC2 extending along side SF3 is formed on side SF3 of the semiconductor light emitting element 10. The Schottky junction SC2 can prevent current from concentrating at the end of the light emitting functional unit 15M, which can cause deterioration of the light emitting functional unit 15M and reduce light output.

[0051] As described above, the light-emitting functional layer 15 including a plurality of light-emitting functional sections 15M has at least one pair of sides facing each other, and has a pair of connection sections along the pair of sides where the p-type semiconductor layer 14 and the light-emitting layer 13 have been removed to expose the n-type semiconductor layer 12 (first semiconductor layer).

[0052] A pair of opposing sides SF1, SF3 in a direction perpendicular to the extension direction of the light-emitting functional section 15M has a pair of connection portions where the p-type semiconductor layer 14 and the light-emitting layer 13 extending along the sides SF1, SF3 have been removed to expose the n-type semiconductor layer 12 (first semiconductor layer), and the auxiliary wiring 21B is in Schottky contact with the n-type semiconductor layer 12 at the connection portions.

[0053] In addition, another pair of opposing sides SF4, SF2 extending in a direction along the light-emitting functional section 15M of the substrate 11 have a pair of connection portions in which the p-type semiconductor layer 14 and the light-emitting layer 13 extending along the sides SF4, SF2 have been removed to expose the n-type semiconductor layer 12 (first semiconductor layer), and the n-electrode 21A is in ohmic contact with the n-type semiconductor layer 12 (first semiconductor layer) at the connection portions.

[0054] (3) Manufacturing method of semiconductor light emitting element A method for manufacturing the semiconductor light emitting device 10 will be described below with reference to the drawings. Figures 4A to 4C are cross-sectional views showing steps S1 to S9 of the manufacturing method. Figures 4A to 4C schematically show cross sections taken along line AA in Figure 1A. That is, the left side of the figure is a cross section of the first region RC1, and the right side is a cross section of the second region RC2.

[0055] (S1) Preparation of epitaxial wafer An epitaxial wafer 10E is prepared in which an n-type semiconductor layer 12, a semiconductor light emitting layer 13, and a p-type semiconductor layer 14 are sequentially crystal-grown on a substrate 11. The layer consisting of the n-type semiconductor layer 12, the semiconductor light emitting layer 13, and the p-type semiconductor layer 14 functions as a light-emitting functional layer 15. Here, sapphire is used for the substrate 11, and GaN-based crystals are used for the semiconductor layers.

[0056] (S2) Division of the light-emitting area A resist mask covering the light-emitting region is formed on the epitaxial wafer 10E. Next, the semiconductor layer in the openings of the resist mask is etched by reactive ion etching (RIE) until the n-type semiconductor layer 12 is exposed. Using a similar method, the n-type semiconductor layer 12 at the edge of the semiconductor light-emitting element 10 is etched until the substrate 11 is exposed.

[0057] The light-emitting functional layer 15 is divided by the grooves 15G formed by etching, and one or more mesa-shaped light-emitting functional portions 15M are formed. Furthermore, the edges of the sides SF1 to SF4 that define the semiconductor light-emitting element 10 are formed. Subsequently, the resist mask is removed. Note that the removal of the resist mask, which is the final step in the following processes, will not be described.

[0058] (S3) Formation of p-electrode A resist mask is formed with an opening in the area where the p-electrode will be formed, i.e., the top surface of the light-emitting function section 15M. Next, an ITO film 23A is formed by sputtering. Next, a Ni / Ag layer 23B is formed on the ITO film 23A by EB (electron beam) method. Subsequently, a Ti / Au layer 23C is formed by EB method.

[0059] As a result, a reflective p-electrode 23 is formed, which is made up of the ITO film 23A, which is a transparent conductive film, the Ni / Ag layer 23B, which is a light-reflecting film, and the Ti / Au layer 23C, which is a protective layer.

[0060] It is to be noted that Pt, Pd, or Rh may be used instead of the Au layer of the Ti / Au layer 23 C. Also, a small amount of Ni, Ti, W, or the like may be deposited on the top layer.

[0061] (S4) Formation of n-electrode A resist mask is formed on the bottom of the groove 15G, with an opening in the portion where the n-electrode is to be formed. Subsequently, a Ti / Al layer is formed by the EB method to form the n-electrode 21A. Note that Pt, Pd, or Rh can also be used instead of the Al layer.

[0062] (S5) Formation of auxiliary wiring A resist mask is formed with openings in areas where the auxiliary wiring 21B is to be formed, other than the light-emitting functional portion 15M. Subsequently, a Ni / Au layer is formed by EB method. The part of this metal layer that contacts the n-type semiconductor layer 12 forms a Schottky junction.

[0063] Next, a Ti / Au layer is formed on the Ni / Au layer by EB to form the auxiliary wiring 21B. Note that Pt, Pd, or Rh can be used instead of the Au layer. A small amount of Ni, Ti, or W may also be formed on the top layer.

[0064] (S6) Formation of first insulating film After the above steps, an SiO2 film is formed by sputtering over the entire processed surface of the wafer. Next, a resist mask is formed with openings in the areas that will become the n-electrode connection portion 22C and the p-electrode connection portion 23C. The SiO2 layer is then removed from the resist mask openings using buffered hydrofluoric acid to form the first insulating film 25. At this time, the Au layer (or Pt, Pd, or Rh layer) of the p-electrode 23 and auxiliary wiring 21B functions as an etching stop layer.

[0065] (S7) Formation of a metal coating layer A resist mask is formed with an opening in the area where the covering metal layer is to be formed. Next, a Ni / Al / Ti / Pt layer is formed by EB method to form the covering metal layer 26. Ni, Ti, or W can also be formed on the top surface of the Pt layer. This improves the adhesion of the second insulating film 27.

[0066] (S8) Formation of second insulating film A resist mask is formed to cover the n-electrode connecting portion 22C and the p-electrode connecting portion 23C. Subsequently, an SiO2 film is formed by sputtering. After that, the resist is lifted off to expose the n-electrode connecting portion 22C and the p-electrode connecting portion 23C.

[0067] (S9) Formation of pad electrodes A resist mask is formed with openings corresponding to the shapes of the first pad electrode 28A and the second pad electrode 28B. Subsequently, a Ti / Au layer is formed by the EB method to form the first pad electrode 28A and the second pad electrode 28B.

[0068] The above steps manufacture the semiconductor light emitting device 10. The film formation method and materials for each layer can be modified as appropriate.

[0069] (4) Mounting on a circuit board The following describes how to mount the semiconductor light emitting element 10 on a circuit board: Fig. 5A is a perspective view showing a method for mounting the semiconductor light emitting element 10 on a circuit board.

[0070] With the first pad electrode 28A (anode) and the second pad electrode 28B (cathode) facing downward, the semiconductor light emitting element 10 is bonded to the anode wiring 43A and the cathode wiring 43B of the circuit board using bonding members 41A and 41B.

[0071] More specifically, first, solder paste solder, which will be the bonding material, is printed on the circuit board wiring, then the semiconductor light emitting element 10 is mounted on the solder paste, and then heated in a reflow furnace for bonding.

[0072] 5B and 5C are a top perspective view and a cross-sectional view taken along line DD in FIG. 5A, respectively, for illustrating the discharge of the flux that has evaporated during reflow.

[0073] The solder paste solder that forms the joining members 41A and 41B contains volatile flux, which volatilizes during reflow. At this time, as shown in FIG. 5B, the slit between the first pad electrode 28A and the second pad electrode 28B serves as a gas exhaust path. When heated from the outside, the solder melts and progresses from the outside to the inside. Therefore, by providing an exhaust path that passes through the final melting point, it is possible to exhaust the flux gas, making it possible to form joining members without voids. This allows for mounting with high heat dissipation.

[0074] (5) Modification example 1 Although the above description has been given of the case where the light-emitting functional layer 15 has a plurality of light-emitting functional portions 15M, the light-emitting functional layer 15 may be configured to have one light-emitting functional portion 15M.

[0075] That is, the light-emitting functional layer 15 may be configured to have one plateau shape in which grooves or steps are provided to expose the n-type semiconductor layer 12 (first semiconductor layer) on a pair of opposing sides (edges). In this case, the first electrode layer 22 can be configured to be in Schottky contact with the n-type semiconductor layer 12 (first semiconductor layer) exposed along the pair of sides.

[0076] (6) Modification example 2 6 is a top view showing a semiconductor light emitting device 10A which is a modified example of the first embodiment of the present invention. In this modified semiconductor light emitting device 10A, insulating pads 29A and 29B are provided in addition to a first pad electrode 28A and a second pad electrode 28B.

[0077] More specifically, the insulating pads 29A, 29B are provided between the first pad electrode 28A and the second pad electrode 28B, and are spaced apart by a distance DG from the first pad electrode 28A and the second pad electrode 28. The insulating pads 29A, 29B are also arranged side by side in a direction perpendicular to the extension direction of the light-emitting function portion 15M.

[0078] The insulating pads 29A, 29B are electrically isolated and spaced apart by a gap passing through the final melting point (see FIG. 5B), which allows for effective evacuation of volatile gases from the solder paste.

[0079] Furthermore, by joining the insulating pad to a heat dissipation means provided on the circuit board, the light emitting element (light emitting device) can be cooled without going through a submount or package substrate.

[0080] Furthermore, the first pad electrode 28A and the second pad electrode 28B are formed so that their pad ends are offset by a distance DP inward from the end of the light-emitting function portion 15M so as not to exceed the end 15E of the light-emitting function portion 15M. This structure prevents stress from being applied to the light-emitting function portion 15M during soldering. Even if the insulating pads 29A and 29B are not provided, it is preferable to form the first pad electrode 28A and the second pad electrode 28B so as to be offset from the end 15E of the light-emitting function portion 15M.

[0081] [Second embodiment] 7 is a cross-sectional view schematically showing a cross section of a semiconductor light emitting device 50 according to a second embodiment of the present invention. The semiconductor light emitting device 50 is a light emitting device that emits mixed color light, and includes the semiconductor light emitting element 10 of the first embodiment and a light guiding member 51. In the following, an example will be described in which the light guiding member 51 is a phosphor plate.

[0082] More specifically, a phosphor plate 51 is adhered onto the semiconductor light emitting element 10 by an adhesive layer 48. The semiconductor light emitting element 10 is a light emitting element (LED) that emits blue light, and the phosphor plate 51 is made of, for example, YAG:Ce, and white mixed color light LM is emitted from the upper surface of the phosphor plate 51. The adhesive layer 48 is made of a light-transmitting adhesive, for example, a light-transmitting silicone resin.

[0083] The semiconductor light emitting element 10 and the phosphor plate 51 have the same outer shape and size, for example, a rectangular plate shape, that is, the semiconductor light emitting element 10 and the phosphor plate 51 have a common outer surface.

[0084] Therefore, the semiconductor light-emitting element 10, the adhesive layer 48, and the phosphor plate 51 constitute a light-emitting element assembly 53. The side surfaces of the light-emitting element assembly 53 are covered with a light-shielding layer 55, which is a coating that adheres closely to the side surfaces.

[0085] The light-shielding layer 55 may be any layer that blocks light from the semiconductor light-emitting element 10, the adhesive layer 48, and the phosphor plate 51, and may be, for example, an alumina layer formed by thermal spraying, a white resin layer, or a dielectric multilayer film layer formed by atomic layer deposition (ALD).

[0086] For example, the light-shielding layer 55 can be formed of a coating made of an inorganic material that is a light reflector. Preferably, the light-shielding layer 55 is a ceramic binder (essentially a sintered body) containing white ceramic and formed by thermal spraying, or a silicate-based binder, which is an inorganic adhesive that uses alumina, zirconia, or the like, which are ceramic particles that bond with siloxane, as an aggregate (main skeleton material).

[0087] It is not necessary for the semiconductor light-emitting element 10 and the phosphor plate 51 to have the same shape or size. It is preferable that the entire side surface of the light-emitting element assembly 53 is covered with a light-shielding layer 55. Furthermore, when multiple semiconductor light-emitting devices 50 are arranged in contact with each other on a circuit board or the like, it is preferable that they have flat side surfaces that can be in close contact with each other.

[0088] The phosphor of the phosphor plate 51 is not limited to those mentioned above. For example, a green light-emitting device can be formed by using an LuAG:Ce phosphor plate, and a red light-emitting device can be formed by using an α-sialon phosphor plate. Furthermore, optical plates such as lenses and diffractive optical elements, and light-guiding members can also be used instead of the phosphor plate 51.

[0089] Although the embodiments of the present invention have been described in detail above, the configurations, crystal systems, materials, and other aspects of the semiconductor layers described above are merely examples, and can be appropriately modified and applied without departing from the scope of the present invention.

[0090] As described above in detail, according to the present invention, it is possible to provide a semiconductor light emitting element and a semiconductor light emitting device that can obtain uniform current injection and light emission and have high light emitting efficiency. [Explanation of symbols]

[0091] 10, 10A: semiconductor light emitting element, 11: substrate, 12: first semiconductor layer, 13: light emitting layer, 14: second semiconductor layer, 15: light emitting functional layer, 15G: groove, 15M: light emitting functional portion, 21A: n-electrode, 21B: auxiliary wiring, 22: first electrode layer, 23: second electrode layer (p-electrode), 25: first insulating film, 26: covering metal layer, 27: second insulating film, 28A: first pad electrode, 28B: second pad electrode, 29A, 29B: insulating pads, OC1, OC2: ohmic contact, SC1, SC2: Schottky contact, 50: semiconductor light emitting device, 51: light guiding member, 53: light emitting element assembly, 55: light-shielding layer

Claims

1. an insulating or semi-insulating substrate; a light-emitting functional layer in which a first semiconductor layer of a first polarity, a light-emitting layer, and a second semiconductor layer of a second polarity are sequentially stacked on the substrate; a first electrode layer provided on the first semiconductor layer of the light-emitting functional layer; a second electrode layer provided on the second semiconductor layer of the light-emitting functional layer; a first insulating layer that covers the light-emitting functional layer and exposes a portion of the first electrode layer and the second electrode layer; a covering metal layer that covers the light-emitting functional layer and is connected to the first electrode layer; a second insulating layer covering the covering metal layer; a first pad electrode connected to the second electrode layer and covering the light emitting function layer and the first and second insulating layers; a second pad electrode connected to the covering metal layer and covering the light emitting function layer and the first and second insulating layers; the light-emitting functional layer has a pair of sides facing each other and a pair of connection portions at which the first semiconductor layer is exposed along the pair of sides; The first electrode layer is in Schottky contact with the pair of connection portions of the first semiconductor layer.

2. the light-emitting functional layer has another pair of sides perpendicular to the pair of sides, and has another pair of connection portions along the other pair of sides at which the first semiconductor layer is exposed, the first electrode layer is in ohmic contact with the other pair of connection portions of the first semiconductor layer; The semiconductor light emitting device according to claim 1 .

3. the light emitting functional layer has a plurality of mesa-shaped light emitting functional portions separated by grooves in which the first semiconductor layer is exposed and extending in a direction perpendicular to the pair of sides, 3. The semiconductor light-emitting element according to claim 1, wherein the first electrode layer has a first electrode piece extending parallel to the light-emitting function portion at the bottom of the groove, and the second electrode layer has a second electrode piece extending parallel to the light-emitting function portion on the top surface of the light-emitting function portion.

4. 4. The semiconductor light emitting element according to claim 1, wherein the first pad electrode and the second pad electrode are spaced apart at a constant interval in a direction perpendicular to the pair of sides.

5. 5. The semiconductor light emitting element according to claim 3, wherein the first pad electrode and the second pad electrode are arranged such that pad ends are offset inward from ends of the plurality of light emitting function portions.

6. 6. The semiconductor light emitting element according to claim 1, further comprising an insulating pad provided between the first pad electrode and the second pad electrode and spaced apart from the first pad electrode and the second pad electrode.

7. The semiconductor light-emitting element according to claim 1 , wherein the second electrode layer has a transparent conductive film provided on the second semiconductor layer and a light-reflecting film provided on the transparent conductive film.

8. a light-emitting element assembly including the semiconductor light-emitting element according to claim 1 and a light-guiding member bonded to the semiconductor light-emitting element by an adhesive layer; a light-shielding layer made of an inorganic material that is a light reflector covering a side surface of the light-emitting element assembly; A semiconductor light emitting device comprising:

9. 9. The semiconductor light-emitting device according to claim 8, wherein the light-shielding layer is a ceramic binder formed by thermal spraying, or a silicate binder which is an inorganic adhesive having siloxane bonds and which uses ceramic particles as aggregates.

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