JP2014093509A - Semiconductor light-emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve light extraction efficiency.SOLUTION: A semiconductor light-emitting element 1 comprises: a semiconductor structure 3 including a first semiconductor layer 4 and a second semiconductor layer 6 provided on one region on the first semiconductor layer 4; a first electrode 31 provided in another region on the first semiconductor layer 4; a second electrode 32 provided on the second semiconductor layer 6; and a light reflection film 20 which covers the semiconductor structure 3. The light reflection film 20 includes an insulation film 25 provided on the semiconductor structure 3 and a metal film 26 provided on the insulation film 25. The first electrode 31 is provided so as to overlap the light reflection film 20 at a peripheral part of the first electrode, in which a region which overlaps the insulation film 25 protruding from the metal film 26 in an opposite manner is arranged closer to the semiconductor structure 3 than a region which overlaps the metal film 26 in an opposite manner.

Description

  The present invention relates to a semiconductor light emitting device, and more particularly to a flip-chip mounted semiconductor light emitting device.

  A semiconductor light emitting device used for flip chip mounting has a structure including, for example, a substrate, a semiconductor layer provided on the substrate, and both a p-side electrode and an n-side electrode on the semiconductor layer. The formed surface (electrode surface) faces downward and is bonded to an external mounting substrate. At this time, as a member for joining the mounting substrate to the p-side electrode and the n-side electrode of the semiconductor light emitting device, generally, for example, bumps, solder, and the like are used.

  A semiconductor light emitting device having both a p-side electrode and an n-side electrode on one surface includes a surface position of a p-side electrode provided on the p-side semiconductor layer and an n-side semiconductor layer exposed by shaving from the p-side. In many cases, the level difference from the surface position of the n-side electrode provided above is large.

  For this reason, various semiconductor light-emitting elements having a complicated structure in which both the p-side electrode and the n-side electrode are arranged on the p-side semiconductor layer have been proposed. The semiconductor light emitting device having such a complicated structure can reduce the step between the p-side electrode and the n-side electrode, thereby improving the flip chip mounting property.

  In addition, a semiconductor light emitting device used for flip chip mounting has been devised to provide a reflective film on the electrode surface side in order to increase light extraction efficiency. For example, a semiconductor light-emitting element including a first reflective layer having an opening and a second reflective layer that reflects light that has passed through the opening is known (see Patent Document 1). In this semiconductor light emitting device, a transparent wiring electrode layer is provided above and below the first reflective layer due to the arrangement relationship of the first reflective layer and the second reflective layer, and the p-side, for example, is formed at the opening of the first reflective layer. By bringing the upper and lower transparent wiring electrode layers into contact with each other, the p-side semiconductor layer and the outermost p-side electrode are made conductive.

JP 2012-69909 A

  However, since the semiconductor light emitting device described in Patent Document 1 requires the first reflective layer and the second reflective layer in order to increase the light extraction efficiency, the transparent wiring electrode is doubled on the p-side semiconductor layer. Layers must be laminated. Therefore, the device structure is complicated by a device for increasing the light extraction efficiency.

  This invention is made | formed in view of the problem mentioned above, and makes it a subject to provide the semiconductor light-emitting device which can improve light extraction efficiency.

  A semiconductor light emitting device according to the present invention includes a semiconductor structure including a first semiconductor layer and a second semiconductor layer provided in one region on the first semiconductor layer, and another region on the first semiconductor layer. A semiconductor light emitting device comprising: a first electrode provided on the second semiconductor layer; a second electrode provided on the second semiconductor layer; and a light reflecting film covering the semiconductor structure, wherein the light reflecting film comprises: An insulating film provided on the semiconductor structure and a metal film provided on the insulating film, and the first electrode is provided so as to overlap the light reflecting film at a peripheral portion thereof. And the region overlapping the insulating film exposed from the metal film is disposed closer to the semiconductor structure than the region overlapping the metal film. To do.

  According to such a configuration, the semiconductor light emitting device can reduce the leakage or absorption of light from the semiconductor structure to the electrode surface side, and can improve the light extraction efficiency.

In the semiconductor light emitting device according to the present invention, it is preferable that the first electrode is formed so that the film thickness becomes thinner toward the end in the region overlapping the metal film.
According to this configuration, the semiconductor light emitting device can reduce the influence of the step due to the metal film in the layer stacked on the first electrode. Thereby, in the layer stacked on the first electrode, the adhesion between the layers can be improved and the occurrence of cracks can be suppressed.

In the semiconductor light emitting device according to the present invention, it is preferable that a surface facing the metal film is curved in a concave shape in a region where the first electrode overlaps the metal film.
According to such a configuration, it is possible to mitigate the influence of the step due to the metal film in the layer stacked between the metal film and the first electrode. Thereby, in the layer stacked between the metal film and the first electrode, the adhesion between the layers can be improved.

  In the semiconductor light emitting device according to the present invention, the second electrode is provided so as to overlap the light reflecting film at an outer peripheral end of the semiconductor structure, and overlaps the metal film. It is preferable that a region overlapping and facing the insulating film exposed from the metal film is disposed closer to the semiconductor structure than a region.

  According to such a configuration, the semiconductor light emitting device can reduce the leakage or absorption of light from the semiconductor structure to the electrode surface side, and can improve the light extraction efficiency.

In the semiconductor light emitting device according to the present invention, the insulating film is preferably a dielectric multilayer film.
According to this configuration, the semiconductor light emitting device can efficiently extract light from the substrate side by reflecting light from the semiconductor structure by the insulating film in the light reflecting film.

Further, in the semiconductor light emitting device according to the present invention, the light reflecting film is a distributed Bragg reflector that is the insulating film from the semiconductor structure side, and the metal film laminated on the distributed Bragg reflector, And a second insulating film laminated on the metal film, wherein the first electrode extends so as to overlap an end portion of the metal film via the second insulating film.
According to this configuration, the distributed Bragg reflector has a small loss due to light reflection, and the metal film has a small wavelength dependency of the light that can be reflected. Therefore, the light reflecting film combining these can efficiently reflect the light from the semiconductor structure.

  In addition, the semiconductor light emitting device according to the present invention covers the end portion of the metal film with the distributed Bragg reflector and the second insulating film, so that current flows through the metal film when the first electrode and the second electrode are energized. It can be prevented from flowing.

Further, in the semiconductor light emitting device according to the present invention, the metal film of the light reflecting film, together with the insulating film, from one region on the second semiconductor layer to a part of another region on the first semiconductor layer. It is preferable that it is extended.
According to such a configuration, the semiconductor light emitting device efficiently transmits light from the substrate side by reflecting light from the semiconductor structure on the side surfaces of the first semiconductor layer and the second semiconductor layer by the metal film in the light reflecting film. Can be taken out well.

  The semiconductor light emitting device according to the present invention can improve the light extraction efficiency. Further, the semiconductor light emitting device according to the present invention can improve the light extraction efficiency without complicating the structure.

It is the schematic plan view which looked at the semiconductor light-emitting device concerning 1st Embodiment of this invention from the electrode surface side. It is a schematic diagram which shows the cross section in the AA arrow of FIG. FIG. 3 is an enlarged view of a region W in FIG. 2. It is a schematic diagram which shows the cross section in the BB line arrow of FIG. It is a schematic diagram which shows the cross section in the CC arrow of FIG. It is a schematic diagram which shows the cross section in the DD arrow of FIG. It is a schematic diagram which shows the cross section in the EE arrow of FIG. It is a schematic diagram which shows the cross section in the FF line arrow of FIG. FIG. 3 is a schematic cross-sectional view corresponding to an enlarged view of a region X in FIG. 2, where (a) shows a first comparative example and (b) shows a semiconductor light emitting device according to a first embodiment of the present invention. It is the schematic sectional drawing to which the area | region X of FIG. 2 was expanded, Comprising: (a) is the 1st modification of the semiconductor light-emitting device which concerns on 1st Embodiment of this invention, (b) has shown the 2nd modification. It is a schematic plan view (the 1) in the manufacturing process of the semiconductor light-emitting device concerning 1st Embodiment of this invention. It is a schematic plan view (the 2) in the manufacturing process of the semiconductor light-emitting device concerning 1st Embodiment of this invention. It is a schematic plan view (the 3) in the manufacturing process of the semiconductor light-emitting device concerning 1st Embodiment of this invention. It is a schematic plan view (the 4) in the manufacturing process of the semiconductor light-emitting device concerning 1st Embodiment of this invention. It is a schematic plan view in the manufacturing process of the semiconductor light-emitting device according to the first embodiment of the present invention (No. 5). It is a schematic plan view (the 6) in the manufacturing process of the semiconductor light-emitting device concerning 1st Embodiment of this invention. It is a schematic plan view in the manufacturing process of the semiconductor light-emitting device concerning 1st Embodiment of this invention (the 7). It is the schematic plan view which looked at the semiconductor light-emitting device concerning 2nd Embodiment of this invention from the electrode surface side. It is a schematic plan view which shows typically the metal film with which the semiconductor light-emitting device which concerns on a 2nd comparative example is provided. It is the schematic plan view which looked at the element during light emission from the electrode surface side, (a) is a 2nd comparative example, (b) has shown the semiconductor light-emitting element which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows an example of the manufacturing method of the metal film shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for implementing a semiconductor light emitting device according to the present invention will be described in detail with reference to drawings showing some specific examples. In addition, when a certain member is “provided on a layer”, it means that a certain member is directly provided on the layer or there may be another member interposed, and a certain member is “on the layer”. When it is “provided directly”, it means that there are no inclusions. The size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same names and symbols indicate the same or the same members in principle, and detailed description will be omitted as appropriate.

(First embodiment)
[Outline of structure of semiconductor light emitting device]
With reference to FIGS. 1 to 3, an outline of the structure of the semiconductor light emitting device 1 according to the first embodiment of the present invention will be described. In FIGS. 2 to 8 and FIG. 21, hatching indicating a cross section is not described in reference numerals 2, 4, 5, 6 252 for easy understanding.

  As shown in FIG. 1, the shape of the semiconductor light emitting device 1 is a rectangle when viewed from the electrode surface side. The semiconductor light emitting element 1 is an element from which light is extracted mainly from the substrate side, and is flip-chip mounted using an alloy as a bonding member. The semiconductor light emitting device 1 is provided with an n-side pad electrode (first pad electrode) 51 and a p-side pad electrode (second pad electrode) 52 on the outermost surface (mounting surface) on the electrode surface side. The structure of the semiconductor light emitting device 1 is a structure in which both the n-side pad electrode 51 and the p-side pad electrode 52 are arranged on the p-side semiconductor layer 6 (see FIG. 2). In FIG. 1, for the sake of clarity, the n-side pad electrode 51 and the p-side pad electrode 52 that are present in the foremost direction in the direction perpendicular to the paper surface are indicated by solid lines, and the regions indicated by reference numerals 7, 8 and the like are broken lines. However, these broken line areas are actually visible in the micrograph.

  As shown in FIG. 2, the semiconductor light emitting device 1 includes a substrate 2, a semiconductor structure 3, translucent conductive films 11 and 12, a light reflecting film 20, an n-side electrode layer (first electrode) 31, and The p-side electrode layer (second electrode) 32, the protective film 40, the n-side pad electrode 51, and the p-side pad electrode 52 are mainly provided. The semiconductor structure 3 is formed on the substrate 2, and includes an n-side semiconductor layer (first semiconductor layer) 4 and a p-side semiconductor layer (second semiconductor layer) provided in a region on the n-side semiconductor layer 4. 6. An active layer 5 is stacked in a region on the n-side semiconductor layer 4, and a p-side semiconductor layer 6 is stacked thereon. In each cross-sectional view including FIG. 2, the electrode side is referred to as the upper side, and the substrate side is referred to as the lower side. In addition, in the cross-sectional view of FIG. 2, one region on the n-side semiconductor layer 4 is divided into left and right sides with the recess 7 therebetween, but the lower side is connected.

  As shown in FIG. 2, an n-side electrode layer 31 is provided in another region (the central recess 7) on the n-side semiconductor layer 4. A p-side electrode layer 32 is provided on the p-side semiconductor layer 6. That is, the n-side electrode layer 31 is provided on the same surface side as the p-side electrode layer 32 with respect to the substrate 2. The light reflecting film 20 covers the semiconductor structure 3 directly or through the light transmitting conductive film 11 or the light transmitting conductive film 12. The light reflecting film 20 includes at least an insulating film 25 (see FIG. 3) provided on the semiconductor structure 3 and a metal film 26 provided on the insulating film 25. FIG. 3 is an enlarged view of a region indicated by W in FIG. In the present embodiment, as shown in FIG. 3, the light reflecting film 20 includes, for example, a first insulating film 24, a DBR (distributed Bragg reflector) 25 that is an insulating film, from the transparent conductive film 12 side, A metal film 26 and a second insulating film 27 are provided. The DBR 25 includes a low refractive index layer 251 and a high refractive index layer 252. Details of these layers will be described later.

  As shown in the X region of FIG. 2, the n-side electrode layer 31 is provided so as to overlap the light reflection film 20 at the peripheral edge thereof. In the present embodiment, the light reflecting film 20 includes a metal film 26 and an insulating film (DBR 25) provided so as to protrude from the metal film 26 between the metal film 26 and the semiconductor structure 3. Since the region where the metal film 26 is provided is narrower than the region where the DBR 25 is provided, a region where the DBR 25 is exposed from the outline of the metal film 26 when the light reflecting film 20 is viewed from above (a region that is visible). is there. FIG. 9B is an enlarged view of the X region in FIG. 2 when the cross section is viewed. As shown in FIG. 9B, the n-side electrode layer 31 has a region 102 that overlaps the surface of the DBR 25 exposed from the metal film 26, rather than a region 101 that overlaps the metal film 26. The semiconductor structure 3 is disposed close to the semiconductor structure 3. Details will be described later.

In the semiconductor light emitting device 1, the semiconductor structure 3 is scraped from the p-side semiconductor layer 6 side in the course of the manufacturing process, and a part thereof is removed. As a result, the semiconductor structure 3 is formed as a region where the n-side semiconductor layer 4 is exposed from the p-side semiconductor layer 6 and on the periphery of the recess 7 surrounded by the p-side semiconductor layer 6 and the outer periphery of the semiconductor structure 3. Peripheral portion 8 (see FIG. 11).
As shown in FIG. 2, the light reflecting film 20 extends from the bottom surface of the recess 7 to the p-side semiconductor layer 6 and to the peripheral portion 8 to cover the semiconductor structure 3.

  As indicated by Z in FIG. 2, the p-side electrode layer 32 is provided so as to overlap the light reflecting film 20 at the outer peripheral end of the semiconductor structure 3. In the region indicated by Z in FIG. 2, the same configuration as the region indicated by X is similarly stacked. Therefore, the enlarged view of the region indicated by Z is the same as FIG. 9B. That is, the p-side electrode layer 32 is disposed closer to the semiconductor structure 3 in the region overlapping the surface of the DBR 25 protruding from the metal film 26 than in the region overlapping the metal film 26. ing.

  As shown in FIGS. 1 and 2, in the present embodiment, the recess 7 has a shape of a groove extending long in the direction along the line EE shown in FIG. In this example, two recesses 7 are formed in the center of the semiconductor structure 3 so as to be separated from each other in the short direction of the recess 7 (the direction along the line CC shown in FIG. 1). The bottom surface of the recess 7 is formed by the n-side semiconductor layer 4, and the side surface (inner peripheral surface) of the recess 7 is formed by the n-side semiconductor layer 4, the active layer 5, and the p-side semiconductor layer 6. In the present embodiment, the translucent conductive film 11 is directly provided on the n-side semiconductor layer 4 of the recess 7. The n-side electrode layer 31 is provided on the n-side semiconductor layer 4 with the translucent conductive film 11 interposed therebetween. The bottom surface of the concave portion 7 is covered with the translucent conductive film 11 at the center of the bottom surface and with the light reflecting film 20 at the periphery of the bottom surface. The side surface (inner peripheral surface) of the recess 7 is covered with the light reflecting film 20. The peripheral portion 8 is formed between the substantial light emitting portion of the semiconductor structure 3 and the dicing line. The peripheral portion 8 is covered with a light reflecting film 20, and a protective film 40 is laminated on the light reflecting film 20.

As shown in FIG. 2, a translucent conductive film 12 is provided on the p-side semiconductor layer 6. A light reflecting film 20 is provided on the translucent conductive film 12. The light reflecting film 20 has a first through hole 21 and a second through hole 22 that expose the translucent conductive film 12.
A p-side electrode layer 32 is provided on the light reflecting film 20. The p-side electrode layer 32 is electrically connected to the translucent conductive film 12 through the first through hole 21. That is, a current flows in the first through hole 21. Therefore, this region is hereinafter referred to as a conduction part 61.
A protective film 40 is provided on the light reflecting film 20 and covers a part of the p-side electrode layer 32. The protective film 40 is in contact with the translucent conductive film 12 through the second through hole 22. That is, no current flows in the second through hole 22. For this reason, this region is hereinafter referred to as a non-conductive portion 62.

  In the present embodiment, the p-side electrode layer 32 has an anchor opening (through hole) 33. The protective film 40 is filled in the anchor opening 33, contacts the translucent conductive film 12 through the anchor opening 33 and the second through-hole 22, and anchors the translucent conductive film 12. Function as.

  The second through hole 22 is provided at the corner of the semiconductor light emitting element 1. By providing the second through hole 22 in which no current flows in the corner, it is possible to prevent the current diffusion in the semiconductor structure 3 from being hindered. The 2nd through-hole 22 is provided in the position which hits under the p side pad electrode 52 as an example. The number of second through holes 22 is one or more. As an example, two second through holes 22 are provided.

  An n-side pad electrode 51 is provided on the n-side electrode layer 31. The n-side pad electrode 51 is electrically connected to the n-side electrode layer 31 through the n-side opening (through hole) 41 of the protective film 40. The n-side pad electrode 51 extends on the p-side electrode layer 32 through the protective film 40.

  As shown on the left side in FIG. 2, a p-side pad electrode 52 is provided above the p-side semiconductor layer 6. The p-side pad electrode 52 is electrically connected to the p-side electrode layer 32 through the p-side opening (through hole) 42 of the protective film 40. The p-side pad electrode 52 is provided on the second through hole 22 with the protective film 40 interposed therebetween.

[Details of structure of semiconductor light emitting device]
The semiconductor light emitting device 1 according to the first embodiment of the present invention will be described in detail with reference to FIGS. 4 to 10 in order (refer to FIG. 1 as appropriate).

FIG. 4 is a schematic cross-sectional view taken along line BB in FIG. As shown in FIG. 4, the p-side pad electrode 52 is continuous above the p-side semiconductor layer 6. The light reflecting film 20 includes a region where the upper surface of the p-side semiconductor layer 6 is not covered with the translucent conductive film 12, the upper surface of the translucent conductive film 12, and the periphery (side surface and n-side semiconductor of the semiconductor structure 3. The upper surface of the layer 4 is continuously formed, and has a plurality of openings on the translucent conductive film 12.
Specifically, in the second through-hole 22, the light-transmitting conductive film 12 / the protective film 40 / p-side pad electrode 52 are stacked in this order from the p-side semiconductor layer 6 side. That is, in the region where the second through hole 22 of the light reflecting film 20 is provided, the translucent conductive film 12 and the p-side pad electrode 52 are insulated from each other by the protective film 40, so that the non-conductive portion 62 (FIG. 2). See).
Further, in the first through hole 21, the transparent conductive film 12 / p-side electrode layer 32 / protective film 40 / p-side pad electrode 52 are stacked in this order from the p-side semiconductor layer 6 side. That is, in the conducting part 61 (see FIG. 2), the light reflecting film 20 is penetrated because the p-side electrode layer 32 is conducted with the translucent conductive film 12.
The metal film 26 included in the light reflecting film 20 extends from a part of the surface of the p-side semiconductor layer 6 to the periphery of the semiconductor structure 3 (side surfaces and the upper surface of the n-side semiconductor layer 4).

As shown in FIG. 4, the p-side electrode layer 32 is continuous above the p-side semiconductor layer 6 and on the light reflecting film 20. However, since the protective film 40 is in contact with the translucent conductive film 12 in the second through hole 22 of the light reflecting film 20, the anchor opening 33 of the p-side electrode layer 32 is in a through state.
The protective film 40 is continuously formed on a region of the upper surface of the light reflecting film 20 that is not covered by the p-side electrode layer 32 and an upper surface of the p-side electrode layer 32, but on the p-side semiconductor layer 6. Has an opening. Specifically, the protective film 40 is penetrated at the location of the p-side opening 42 because the p-side pad electrode 52 is electrically connected to the p-side electrode layer 32.

FIG. 5 is a schematic cross-sectional view taken along the line CC in FIG. As shown in FIG. 5, the n-side pad electrode 51 is continuous above the p-side semiconductor layer 6. The light reflecting film 20 is provided in the same manner as the laminated state shown in FIG. However, the 2nd through-hole 22 is not formed in CC cross section.
The p-side electrode layer 32 is provided similarly to the stacked state shown in FIG. However, the anchor opening 33 is not formed in the CC cross section.
The protective film 40 is continuously formed on a region where the p-side electrode layer 32 is not covered with the upper surface of the light reflecting film 20 and the upper surface of the p-side electrode layer 32.

  6 is a schematic cross-sectional view taken along line DD in FIG. As shown in FIG. 6, the p-side pad electrode 52 and the n-side pad electrode 51 are provided apart from each other at the position of the mounting surface above the p-side semiconductor layer 6. The light reflecting film 20, the p-side electrode layer 32, and the protective film 40 are provided in the same manner as in the stacked state shown in FIG.

  7 is a schematic cross-sectional view taken along line EE in FIG. As shown in FIG. 7, the p-side pad electrode 52 and the n-side pad electrode 51 are provided so as to be separated from each other via the recess 7. The light reflection film 20 is in the same stacked state as in FIG. 4 on the p-side semiconductor layer 6 and on the periphery of the semiconductor structure 3. However, the 2nd through-hole 22 is not formed in the EE cross section. On the p-side semiconductor layer 6, the light reflecting film 20 is interposed between the translucent conductive film 12 and the p-side electrode layer 32, but as shown in FIG. Since the p-side electrode layer 32 is electrically connected to the translucent conductive film 12, the p-side electrode layer 32 is penetrated. Further, the light reflecting film 20 covers a part of the inner surface of the recess 7. Specifically, the light reflection film 20 includes, in the recess 7, a region that is not covered with the light-transmitting conductive film 11 on the upper surface of the n-side semiconductor layer 4, a partial upper surface of the light-transmitting conductive film 11, It is continuously formed on the side surface of the semiconductor structure 3. However, the light reflecting film 20 has a groove-like third through hole 23 extending on the translucent conductive film 11 and extending in the longitudinal direction of the recess 7 (the direction along the line EE). That is, in the recess 7, the n-side electrode layer 31 is electrically connected to the translucent conductive film 11, so that the light reflecting film 20 is penetrated.

  As shown in FIG. 7, the stacked members differ depending on the position in the third through hole 23. For example, in the position on the left side in FIG. 7, there is a region where the transparent conductive film 11 / n-side electrode layer 31 / protective film 40 / p-side pad electrode 52 are stacked in this order from the n-side semiconductor layer 4 side. Exists. Further, in the right position in FIG. 7, there is a region where the light-transmitting conductive film 11 / n-side electrode layer 31 / n-side pad electrode 51 are stacked in this order from the n-side semiconductor layer 4 side. In the region sandwiched between these two regions, the transparent conductive film 11 / n-side electrode layer 31 / protective film 40 are stacked in this order from the n-side semiconductor layer 4 side.

  As shown in FIG. 7, the metal film 26 included in the light reflection film 20 extends from one region on the p-side semiconductor layer 6 to a part of the bottom surface of the recess 7 together with the DBR 25. In the recess 7, the metal film 26 and the DBR 25 (see FIG. 9B) are located between the translucent conductive film 11 and the n-side electrode layer 31. As shown in FIG. 7, on the p-side semiconductor layer 6, the metal film 26 and the DBR 25 (see FIG. 9B) are located between the translucent conductive film 12 and the p-side electrode layer 32. .

  As shown in FIG. 7, the protective film 40 is in the same stacked state as in FIG. 4 on the p-side semiconductor layer 6 and on the periphery of the semiconductor structure 3. Further, the protective film 40 covers a part of the inner surface of the recess 7. Specifically, the protective film 40 includes a region that is not covered by the n-side electrode layer 31 and a part of the n-side electrode layer 31 in the light reflecting film 20 provided on the bottom surface and the inner peripheral surface of the recess 7. And the upper surface. However, the protective film 40 has an n-side opening 41 on the n-side electrode layer 31. That is, in the n-side opening 41 of the protective film 40, the protective film 40 is penetrated because the n-side pad electrode 51 is electrically connected to the n-side electrode layer 31. The n-side pad electrode 51 extends from the n-side opening 41 to the p-side semiconductor layer 6 (right side in FIG. 7). The p-side pad electrode 52 extends from the p-side semiconductor layer 6 (left side in FIG. 7) to the bottom surface of the recess 7.

FIG. 8 is a schematic cross-sectional view taken along the line F-F in FIG. 1. As shown in FIG. 8, the p-side pad electrode 52 and the n-side pad electrode 51 are provided apart from each other at the position of the mounting surface above the p-side semiconductor layer 6. The light reflecting film 20 is continuously formed on the upper surface of the p-side semiconductor layer 6 in a region not covered with the light-transmitting conductive film 12, on the light-transmitting conductive film 12, and on the periphery of the semiconductor structure 3. Has been. The metal film 26 included in the light reflecting film 20 extends from one peripheral edge (side surface and top surface of the n-side semiconductor layer 4) of the semiconductor structure 3 to the surface of the p-side semiconductor layer 6 and the other peripheral edge of the semiconductor structure 3 ( Side surfaces and the upper surface of the n-side semiconductor layer 4).
The p-side electrode layer 32 is continuous above the p-side semiconductor layer 6 and on the light reflecting film 20. The light reflecting film 20 is interposed between the translucent conductive film 12 and the p-side electrode layer 32. However, as shown in FIG. In order to conduct with the conductive film 12, the conductive film 12 is penetrated.
The protective film 40 is continuously formed on a region of the upper surface of the light reflecting film 20 that is not covered by the p-side electrode layer 32 and an upper surface of the p-side electrode layer 32, but on the p-side semiconductor layer 6. Has an opening. Specifically, the protective film 40 is penetrated at the location of the p-side opening 42 because the p-side pad electrode 52 is electrically connected to the p-side electrode layer 32.

FIG. 9 is a cross-sectional view corresponding to an enlarged view of the region X of FIG. 2, wherein (a) shows a first comparative example, and (b) shows a semiconductor light emitting device according to the first embodiment of the present invention. Yes.
The first comparative example shown in FIG. 9A includes an n-side electrode layer 131, and the semiconductor light emitting device according to the first embodiment of the present invention illustrated in FIG. 9B includes an n-side electrode layer 31. Yes. The first comparative example shown in FIG. 9A is the same light reflecting film 20 (first insulating film 24, DBR 25, metal film) as the semiconductor light emitting device according to the first embodiment of the present invention shown in FIG. 9B. 26, a second insulating film 27).

  As shown in FIGS. 9A and 9B, the n-side electrode layers 131 and 31 are provided so as to overlap the light reflecting film 20. Therefore, the light from the semiconductor structure 3 indicated by the white arrow in FIGS. 9A and 9B can be reduced from passing between the light reflecting film 20 and the n-side electrode layers 131 and 31, Light leaking from the light reflection film 20 at the overlapping portion of the n-side electrode layers 131 and 31 and the light reflection film 20 can be reflected by the n-side electrode layers 131 and 31.

  However, the n-side electrode layer 131 shown in FIG. 9A and the n-side electrode layer 31 shown in FIG. 9B are different in shape. Specifically, the n-side electrode layer 131 illustrated in FIG. 9A is stacked on the flat surface of the second insulating film 27, and includes a region 101 that is opposed to the metal film 26 and the metal film 26. The region 102 that overlaps the surface of the protruding DBR 25 is located at the same height from the light reflecting film 20. That is, the region 101 and the region 102 of the n-side electrode layer 131 are located at the same height separated from the uppermost surface of the DBR 25 by the distance α. Note that the surface of the DBR 25 protruding from the metal film 26 refers to a region where the upper surface of the DBR 25 is not covered with the metal film 26.

  On the other hand, the n-side electrode layer 31 shown in FIG. 9B is laminated on the stepped surface of the second insulating film 27, and the metal film 26 rather than the region 101 that overlaps the metal film 26. The region 102 that faces the surface of the DBR 25 that protrudes from and overlaps with the semiconductor structure 3 is disposed. That is, the region 101 of the n-side electrode layer 31 is located at a height that is separated from the top surface of the DBR 25 by a distance α, whereas the region 102 of the n-side electrode layer 31 is a distance from the top surface of the DBR 25. It is located at a height separated by β (β <α). Accordingly, in the n-side electrode layer 31 shown in FIG. 9B, in the region 102, the light incident on the n-side electrode layer 31 from the semiconductor structure 3 is applied to the n-side electrode layer 131 shown in FIG. Compared to effective reflection. Therefore, the n-side electrode layer 31 shown in FIG. 9B can reduce light absorption and improve the light extraction efficiency compared to the n-side electrode layer 131 shown in FIG. 9A.

  Further, when the film thicknesses of the low refractive index layer 251 and the high refractive index layer 252 of the DBR 25 are γ, the value of the distance β between the region 102 of the n-side electrode layer 31 and the uppermost surface of the DBR 25 is set to The value can be several times as large as γ. In particular, when the value of the distance β is set to the same value as the film thickness of the DBR 25 (in this case, 6 × γ), the second insulating film 27 functions as a part of the dielectric multilayer film in the region 102 to reduce light absorption. This is preferable. In this case, the material forming the second insulating film 27 may be the same as the material of the insulating layer forming the second layer from the uppermost layer of the DBR 25 (in this case, the high refractive index layer 252).

  FIG. 10 is an enlarged cross-sectional view of the region X of FIG. 2, wherein (a) shows a first modification of the semiconductor light emitting device according to the first embodiment of the present invention, and (b) shows a second modification. ing. The n-side electrode layer 31a shown in FIG. 10A is formed so that the film thickness becomes thinner toward the end in the region 101 facing and overlapping the metal film 26, as shown in FIG. 9B. This is different from the electrode layer 31. Thereby, in the layer (the protective film 40 and the n-side pad electrode 51) stacked on the n-side electrode layer 31a, the influence of the step due to the metal film 26 can be reduced. Therefore, the first modification of the semiconductor light emitting device can improve the adhesion between layers and suppress the occurrence of cracks in the layer stacked on the n-side electrode layer 31a.

The n-side electrode layer 31b shown in FIG. 10B is shown in FIG. 9B in that the surface 103 facing the metal film 26 is curved in a concave shape in the region 101 facing and overlapping the metal film 26. This is different from the n-side electrode layer 31. Thereby, in the layer (second insulating film 27) stacked between the metal film 26 and the n-side electrode layer 31b, the influence of the step due to the metal film 26 can be reduced. Therefore, the second modification of the semiconductor light emitting device can improve the interlayer adhesion in the layer stacked between the metal film 26 and the n-side electrode layer 31b.
In the region Z of FIG. 2, the end portion of the p-side electrode layer 32 is formed in the same manner as the end portion of the n-side electrode layer 31 shown in FIG. 9B, for example.

[Details of Components of Semiconductor Light Emitting Element]
Hereinafter, each component in the semiconductor light emitting device 1 shown in FIG. 2 will be described in detail.

(Substrate 2)
As the material of the substrate 2, a material suitable when, for example, a gallium nitride compound semiconductor is used for the semiconductor structure 3 is used. Examples of such a substrate material include sapphire, spinel, SiC, Si, ZnO, and GaN single crystal. In particular, it is preferable to use a sapphire substrate in order to form gallium nitride with good crystallinity with high productivity. On the substrate 2, irregularities are formed on the surface on which the semiconductor structure 3 is laminated (surface on the electrode side). The unevenness can scatter or diffract light from the semiconductor structure 3 to increase light extraction efficiency.

(Semiconductor structure 3)
In the semiconductor structure 3, one or both of the n-side semiconductor layer 4 that is the first semiconductor layer and the p-side semiconductor layer 6 that is the second semiconductor layer may be formed of a plurality of semiconductor layers. The active layer 5 may be a single layer or a multilayer. Therefore, for example, each of the n-side semiconductor layer 4 and the p-side semiconductor layer 6 can be composed of a plurality of layers corresponding to necessary functions such as a contact layer and a clad layer, thereby realizing light emission characteristics according to applications. can do.

<N-side semiconductor layer 4>
Examples of the contact layer of the n-side semiconductor layer 4 include a Si-doped n-type GaN layer. Examples of the cladding layer of the n-side semiconductor layer 4 include a Si-doped n-type AlGaN layer.

<P-side semiconductor layer 6>
Examples of the contact layer of the p-side semiconductor layer 6 include an Mg-doped p-type GaN layer. Examples of the cladding layer of the p-side semiconductor layer 6 include an Mg-doped p-type AlGaN layer.

<Active layer 5>
The active layer 5 is an InGaN layer, a single or multiple quantum well layer of GaN and InGaN, a single or multiple quantum well layer composed of an InGaN barrier layer and an InGaN well layer having a different composition ratio.

  Note that the n-side semiconductor layer 4 and the p-side semiconductor layer 6 may further include an undoped semiconductor layer. In addition, if the n-side semiconductor layer 4, the active layer 5, and the p-side semiconductor layer 6 function as a semiconductor light emitting device, for example, the first semiconductor layer is a p-side semiconductor layer and the second semiconductor layer is an n-type semiconductor layer. You may employ | adopt the structure used as a side semiconductor layer.

(Translucent conductive film 11)
The translucent conductive film 11 is provided on the n-side semiconductor layer 4 and functions as an ohmic electrode. The translucent conductive film 11 is formed of a thin film made of a metal, an alloy, or a conductive metal oxide. For example, a metal thin film in which Ni and Au are stacked in order from the n-side semiconductor layer 4 side, a thin film of an alloy of Ni and Au, and the like can be used. In the case of a metal layer or an alloy layer, translucency can be ensured by forming it as a thin film.
Examples of the conductive metal oxide (oxide semiconductor) include a conductive oxide film containing at least one element selected from the group consisting of zinc, indium, tin, gallium, and magnesium. Specifically, indium oxide containing tin (Indium Tin Oxide; ITO), ZnO, In ₂ O _3, SnO ₂ or the like can be given. Particularly for conductive metal oxides, ITO is most preferable from the viewpoints of conductivity and translucency.

(Translucent conductive film 12)
The translucent conductive film 12 is provided on the p-side semiconductor layer 6 and functions as an ohmic electrode. The material of the translucent conductive film 12 is the same as that of the translucent conductive film 11. The translucent conductive film 12 is made of, for example, ITO.

(Light reflecting film 20)
<First insulating film 24>
The first insulating film 24 is a layer that becomes a base of the DBR 25. The first insulating film 24 is particularly preferably made of an oxide film. Examples of the oxide film include Nb ₂ O ₅ , TiO ₂ , SiO ₂ , Al ₂ O ₃ , ZrO _{2 and the} like. Such a first insulating film is, for example, a sputtering method, an ECR (Electron Cyclotron Resonance) sputtering method, a CVD (Chemical Vapor Deposition) method, an ECR-CVD method, or an ECR-plasma CVD method. It can be formed by a known method such as vapor deposition or EB (Electron Beam).

<DBR25>
As shown in FIG. 3, the DBR 25 is a dielectric multilayer film in which a set of dielectrics composed of a low-refractive index layer 251 and a high-refractive index layer 252 is laminated over a plurality of sets, and selects light of a predetermined wavelength. Is reflective. Specifically, films having different refractive indexes can be alternately stacked with a thickness of ¼ wavelength, and a predetermined wavelength can be reflected with high efficiency. The material film is preferably selected from at least one oxide or nitride selected from the group consisting of Si, Ti, Zr, Nb, Ta, and Al.

When the DBR 25 is formed of an oxide film, the low refractive index layer 251 is formed of, for example, SiO ₂ . At this time, the high refractive index layer 252 is formed of, for example, Nb ₂ O ₅ , TiO ₂ , ZrO ₂ , Ta ₂ O ₅ or the like. The DBR 25 is composed of, for example, (Nb ₂ O ₅ / SiO ₂ ) _n (where n is a natural number) in order from the first insulating film 24 side. The DBR 25 is preferably configured so that the natural number n is 2 to 5, preferably 3 to 4. The total film thickness of DBR25 is preferably 0.2 to 1 μm, and more preferably 0.3 to 0.6 μm. FIG. 3 illustrates the case where n = 3.

<Metal film 26>
The metal film 26 is included in the light reflecting film 20 and is based on the premise that no current flows. The metal film 26 is formed of, for example, a highly reflective metal or alloy such as Al or Ag. In the case of Al alone, a high output element can be obtained. In the case of an Al alloy, an alloy of Al and a platinum group metal such as Cu, Ag, or Pt can be used. Among them, an alloy of Al and Cu (AlCu) can be a highly reliable element. Such a metal film 26 can be formed by a known method such as sputtering.
The metal film 26 can also be composed of a plurality of layers. In the case where the metal film 26 has two layers, for example, a structure in which AlCu / Ti is laminated in this order from the DBR 25 side is exemplified. In this case, the material laminated on the AlCu is provided in consideration of adhesion with the material of the second insulating film 27 formed thereon. For example, when the material of the second insulating film 27 is SiO ₂ , the material laminated on the AlCu is preferably Ti.

  Since the metal film 26 is formed on the DBR 25, the light transmitted from the semiconductor structure 3 through the DBR 25 can be reflected. The DBR 25 has an advantage that there is little loss due to reflection because it totally reflects light at a predetermined incident angle, but there is a disadvantage that the reflectivity decreases when the incident angle of light is large. On the other hand, the metal film 26 has an advantage that the incident angle range in which light can be reflected is large, and the wavelength range of light that can be reflected is large. By combining such DBR 25 and metal film 26, incident light can be efficiently reflected.

<Second insulating film 27>
The second insulating film 27 is a layer that covers and protects the metal film 26. The n-side electrode layer 31 extends so as to overlap the end portion of the metal film 26 with the second insulating film 27 interposed therebetween. The end of the metal film 26 is covered with the DBR 25 and the second insulating film 27. Similarly to the first insulating film 24, the second insulating film 27 is made of an oxide film such as SiO ₂ . Note that the material of the second insulating film 27 may be the same as or different from the material of the first insulating film 24.

<Through hole of light reflecting film 20>
The light reflecting film 20 includes a first through hole 21, a second through hole 22, and a third through hole 23 (see FIG. 14). In FIG. 14, the first through holes 21 are provided in an 8 × 10 grid as an example. Among these, the upper left and the lower left are replaced with the second through holes 22. The number and arrangement of the first through holes 21 and the second through holes 22 are not limited to this. The third through hole 23 is a groove along the longitudinal direction of the recess 7 and is formed narrower than the bottom surface of the recess 7.

  The average diameter of the second through hole 22 is set to a predetermined range size. Here, the average diameter means the average value of the major axis and the minor axis when the planar shape of the second through hole 22 is not circular, for example, when it is an ellipse, and when it is a square, the area of the square Is the diameter of a circle with the same area. When the average diameter is less than 5 μm, the resist pattern for etching is crushed and it is difficult to manufacture the second through hole 22. Further, when the average diameter exceeds 15 μm, the second through hole 22 may inhibit current diffusion. Therefore, the average diameter of the second through holes 22 is preferably 5 μm or more and 15 μm or less. In the case of the first through hole 21 through which a current flows, the average diameter is preferably 10 μm or more in order to improve the current characteristics.

(N-side electrode layer 31)
The n-side electrode layer 31 is an electrode layer provided between the translucent conductive film 11 and the n-side pad electrode 51. The n-side electrode layer 31 is formed by stacking, for example, Ti, Rh, and Ti in order from the translucent conductive film 11 side. If the material which comprises the n side electrode layer 31 is a material which can be in ohmic contact with the n side semiconductor layer 4, other materials, such as a laminated body and an alloy which combined another metal, can also be used. As a modification, the n-side electrode layer 31 may be in direct contact with the n-side semiconductor layer 4 without the light-transmitting conductive film 11 interposed.

(P-side electrode layer 32)
The p-side electrode layer 32 is an electrode layer provided between the translucent conductive film 12 and the p-side pad electrode 52. The p-side electrode layer 32 is provided on the translucent conductive film 12. The material of the p-side electrode layer 32 is the same as that of the n-side electrode layer 31. The p-side electrode layer 32 is formed by laminating, for example, Ti, Rh, and Ti in order from the translucent conductive film 12 side.

(Protective film 40)
The protective film 40 covers and protects the surface of the semiconductor light emitting element 1. The protective film 40 is made of an insulating film, and is particularly preferably made of an oxide film. The protective film 40 is made of, for example, SiO ₂ or a Zr oxide film (ZrO ₂ ). The protective film 40 can be formed by a known method such as sputtering, ECR sputtering, CVD, ECR-CVD, ECR-plasma CVD, vapor deposition, or EB. For example, when forming the protective film 40 with SiO ₂ , a CVD film (CVD-TEOS) using TEOS (Tetra Ethyl Ortho Silicate) as a raw material can be used.

<Through hole of protective film 40>
The protective film 40 includes through holes 41 and 42 (see FIGS. 2 and 16). The n-side opening (through hole) 41 of the protective film 40 is made small enough to expose a portion of the n-side electrode layer 31 provided in the recess 7 at the position where the n-side pad electrode 51 is formed. Has been.
The p-side opening (through hole) 42 of the protective film 40 is provided in a portion close to the n-side electrode layer 31 (portion close to the element center) at a position where the p-side pad electrode 52 is formed. . By forming at such a position, current diffusion in the semiconductor structure 3 can be prevented from being hindered. The p-side opening 42 is made as large as possible so as to reduce the resistance. The size of the p-side opening 42 shown in FIG. 16 is merely an example, and may be less than half the size shown.

(N-side pad electrode 51)
The n-side pad electrode 51 is an electrode layer that becomes the n-side outermost surface when the semiconductor light emitting element 1 is mounted, and is electrically connected to the n-side electrode layer 31. For example, the n-side pad electrode 51 is formed by laminating Ti, Pt, and Au sequentially from the n-side electrode layer 31 side. Alternatively, for example, the n-side pad electrode 51 may be formed by stacking Ti, Ni, and Au sequentially from the n-side electrode layer 31 side.
As shown in FIG. 1, the n-side pad electrode 51 and the p-side pad electrode 52 have a vertically long rectangular shape, but the n-side pad electrode 51 has a notch 53 formed therein. The notch 53 serves as a mark for the cathode (n-side electrode).

(P-side pad electrode 52)
The p-side pad electrode 52 is an electrode layer that is the outermost surface on the p side when the semiconductor light emitting element 1 is mounted, and is electrically connected to the p-side electrode layer 32. Similar to the n-side pad electrode 51, for example, the p-side pad electrode 52 is formed by laminating Ti, Pt, Au, and the like in this order from the p-side electrode layer 32 side.

[Method for Manufacturing Semiconductor Light-Emitting Element]
A method of manufacturing the semiconductor light emitting device 1 according to the present invention will be described with reference to FIGS. 11 to 17 (refer to FIGS. 1 to 3 as appropriate). In actual mass production, a large number of semiconductor light emitting elements 1 are arranged in a matrix on a large substrate, and the large substrate is cut by a dicing line to be separated into individual elements. FIGS. 11 to 17 are schematic plan views showing a manufacturing process of an element according to the present invention, focusing on one semiconductor light emitting element 1 for the sake of explanation.

  First, as shown in FIG. 2, the n-side semiconductor layer 4, the active layer 5, and the p-side semiconductor layer 6 are stacked in this order on the substrate 2 to form the semiconductor structure 3. Then, a part of the semiconductor structure 3 is etched by, for example, RIE (Reactive Ion Etching reactive ion etching) as shown in FIG. At this time, for example, etching is performed using the mask pattern having a shape corresponding to the concave portion 7 and the peripheral portion 8 so that the surface of the n-side semiconductor layer 4 is exposed from the p-side semiconductor layer 6 side.

  Next, a translucent electrode material is laminated on the surface of the semiconductor structure 3 using a sputtering method. As a result, as shown in FIG. 12, a translucent conductive film 11 is formed on the upper surface of the n-side semiconductor layer 4 exposed from the p-side semiconductor layer 6 in the recess 7, and the upper surface of the p-side semiconductor layer 6 is transparent. A photoconductive film 12 is formed.

  Next, the first insulating film 24 of the light reflecting film 20 is formed on the entire surface (on the p-side semiconductor layer 6, the recess 7, and the periphery of the semiconductor structure 3) from above the translucent conductive films 11 and 12 by sputtering. And DBR 25 (three pairs of high refractive index layer 252 / low refractive index layer 251). Subsequently, a metal film 26 is patterned on the DBR 25. Specifically, after forming a resist in a region where the metal film is not laminated, a metal material such as Al is formed by sputtering, and then the resist and the metal film on the resist are removed by lift-off. As a result, the metal film 26 was patterned. Thereby, as shown in FIG. 13, a metal film 26 having a large number of openings is formed.

  Next, the second insulating film 27 is laminated on the entire surface of the patterned metal film 26 (on the p-side semiconductor layer 6, the recess 7, and the periphery of the semiconductor structure 3) by sputtering. Thereafter, the first through hole 21, the second through hole 22, and the third through hole 23 are pattern-formed by dry etching (for example, RIE). Thereby, as shown in FIG. 14, the light reflecting film 20 having the first through hole 21, the second through hole 22, and the third through hole 23 is formed.

  Subsequently, the n-side electrode layer 31 and the p-side electrode layer 32 are patterned on the light reflecting film 20 except for the portion that becomes the anchor opening (through hole) 33. Specifically, after a resist is formed on the light reflection film 20 in a portion that becomes the anchor opening 33 including the second through-hole 22, an electrode material such as Rh is formed using a sputtering method, Thereafter, the resist and the electrode material on the resist were removed by lift-off. Thereby, as shown in FIG. 15, the n-side electrode layer 31 is formed in the recess 7, and the p-side electrode layer 32 is formed on the upper surface of the p-side semiconductor layer 6. At this time, an anchor opening (through hole) 33 larger than the second through hole 22 is formed in the p-side electrode layer 32. The n-side electrode layer 31 is filled in the third through hole 23 of the light reflecting film 20 and is laminated on the translucent conductive film 11. The p-side electrode layer 32 is filled in the first through hole 21 of the light reflecting film 20 and is laminated on the translucent conductive film 12.

Next, on the entire surface (on the p-side semiconductor layer 6, the recess 7 and the periphery of the semiconductor structure 3) from above the n-side electrode layer 31 and the p-side electrode layer 32, as shown in FIG. A protective film 40 such as ₂ is formed. At this time, the anchor opening 33 is filled with the protective film 40, and the protective film 40 is laminated on the translucent conductive film 12 through the second through hole 22. Thereafter, the protective film 40 is dry-etched (for example, RIE) to form an n-side opening (through hole) 41 and a p-side opening (through hole) 42 as electrode connection portions. At this time, the n-side opening 41 is formed in a part of the third through hole 23 on the side (the right side in FIG. 16) that becomes the n-side pad electrode 51. The p-side opening 42 is formed so as to include the plurality of first through holes 21 on the side (left side in FIG. 16) that becomes the p-side pad electrode 52 with the recess 7 interposed therebetween.

  Subsequently, an n-side pad electrode 51 and a p-side pad electrode 52 are patterned on the protective film 40. Specifically, after forming a resist in a region where an electrode is not formed, an electrode material such as Pt or Au is manufactured by sputtering so as to cover a part of the p-side semiconductor layer 6 and the recess 7. Then, the resist and the electrode material on the resist are removed by lift-off. Thereby, as shown in FIG. 17, an n-side pad electrode 51 and a p-side pad electrode 52 are formed. Subsequently, the large-sized substrate is cut by a dicing line and separated into individual elements. Note that the separated element is used to manufacture the light emitting device by being bonded directly to the substrate of the light emitting device or indirectly through the submount substrate using an alloy as a bonding member.

  Specific materials for the bonding member include In, Pb—Pd, Au—Ga, Au and Ge, Si, In, Zn, and Sn, Al and Zn, Ge, Mg, Si, and In. , Cu and Ge, In, Ag—Ge, and Cu—In alloys. Preferably, a eutectic alloy film is used. For example, an alloy containing Au and Sn as main components, an alloy containing Au and Si as main components, an alloy containing Au and Ge as main components, Sn and Cu, and the like. And the like.

According to the semiconductor light emitting device 1 of the first embodiment, the n-side electrode layer 31 is incident on the n-side electrode layer 31 from the semiconductor structure 3 in the region 102 that overlaps the surface of the DBR 25 protruding from the metal film 26. Since the reflected light can be reflected effectively, light absorption can be reduced and light extraction efficiency can be improved.
In addition, according to the semiconductor light emitting device 1, the protective film 40 is in close contact with the translucent conductive film 12 via the second through hole 22 provided in the light reflecting film 20 and functions as an anchor. The translucent conductive film 12 that is in contact with the protective film 40 through the second through-hole 22 prevents the protective film 40 from peeling off from the p-side electrode layer 32. Therefore, the semiconductor light emitting device 1 can improve the adhesion between the p-side electrode layer 32 and the protective film 40.
Furthermore, the semiconductor light emitting device 1 has a structure in which both the n-side pad electrode 51 and the p-side pad electrode 52 are arranged on the p-side semiconductor layer 6 and is flip-chip mounted as compared with the conventional simple structure. Since the joining area is large, the joining strength / accuracy and heat dissipation can be improved.

  The second to fourth embodiments will be described below with reference to FIGS. 18 to 21 (see FIGS. 1 and 2 as appropriate).

(Second Embodiment)
FIG. 18 is a plan view of the semiconductor light emitting device according to the second embodiment of the present invention as viewed from the electrode surface side. As shown in FIG. 18, the semiconductor light emitting element 1A includes an n-side pad electrode 51 and a p-side pad electrode 52A. The p-side pad electrode 52A is different from the semiconductor light emitting device 1 shown in FIGS. 1 and 2 in that the p-side pad electrode 52A is formed only on the p-side semiconductor layer 6 and is not formed in the recess 7. In this case, the same effects as those of the semiconductor light emitting device 1 of the first embodiment can be achieved while reducing the material for the pad electrode.

A semiconductor light emitting device 1A according to the second embodiment was manufactured under the following main film forming conditions, and the light emission performance was examined.
[Film forming conditions]
A recess 7 was formed by etching a part of the semiconductor structure 3 made of GaN by RIE to expose the n-side semiconductor layer 4 at a depth of 1.2 μm.
<Translucent conductive films 11, 12>
ITO was laminated with a film thickness of 120 nm.
<Light Reflecting Film 20>
The first insulating film 24 was laminated with a film thickness of 500 nm using SiO ₂ as a material.
The DBR 25 is composed of (Nb ₂ O ₅ / SiO ₂ ) ₃ in order as a high refractive index layer 252 / low refractive index layer 251 from the first insulating film 24 side.
The total film thickness of DBR25 was 1060 nm (film thickness γ = 177 nm).
The metal film 26 has a two-layer structure of AlCu / Ti from the DBR 25 side, the film thickness of AlCu is 200 nm, and the film thickness of Ti is 10 nm. The Cu content in AlCu was 3%. The metal film 26 was laminated in the range shown in FIG.
The second insulating film 27 was laminated with a thickness of 200 nm using SiO ₂ as a material.
<N-side electrode layer 31, p-side electrode layer 32>
Ti (0.15 nm) / Rh (250 nm) / Ti (10 nm) were laminated in order from the semiconductor structure 3 side.
<Protective film 40>
A 700 nm SiO ₂ film was formed using a CVD film (CVD-TEOS) using TEOS as a raw material.
<N-side pad electrode 51, p-side pad electrode 52>
Ti (200 nm) / Ni (100 nm) / Au (50 nm) were laminated in order from the semiconductor structure 3 side.

[Performance comparison experiment]
As an example, a semiconductor light emitting device 1A formed under the above film forming conditions was manufactured. As a comparative example, a semiconductor light emitting device with a reduced range of forming the metal film in the light reflecting film 20 was manufactured.
FIG. 19 shows the range of the metal film 226 of the comparative example. In the comparative example, as shown in FIG. 19, the metal film 226 was formed only on the p-side semiconductor layer 6 of the semiconductor structure 3. A second insulating film 27 was laminated thereon to form a light reflecting film 20, and a semiconductor light emitting device of a comparative example was completed. That is, in the semiconductor light emitting device of the comparative example, the n-side electrode layer 31 does not overlap the metal film 226.

  In the example, as shown in FIG. 13, a metal film 26 was formed on the n-side semiconductor layer 4 in addition to the p-side semiconductor layer 6 of the semiconductor structure 3. Specifically, in the example, an AlCu alloy was formed on the p-side semiconductor layer 6, a part and side surfaces of the bottom surface of the recess 7 of the semiconductor structure 3, and the peripheral portion 8. In the semiconductor light emitting device of the example, the n-side electrode layer 31 overlaps the metal film 26, and the n-side electrode layer 31 is formed as shown in FIG.

FIG. 20A shows the result of observation of an image of light transmitted to the electrode surface side in the comparative example. Similarly, the results of the example are shown in FIG.
As shown in FIG. 20A, it can be seen that light leaks from the side surface (inner peripheral surface) of the recess 7 in the comparative example. In FIG. 20A, no light leaks on the right side. This is because the n-side pad electrode 51 covers a part on the right side of the recess 7.
In the embodiment, since the metal film 26 covers a part of the bottom surface and the side surface of the recess 7 of the semiconductor structure 3, as shown in FIG. 20B, light is emitted from the side surface (inner peripheral surface) of the recess 7. It can be seen that is not leaking.
When the light emission output (mW) of the semiconductor light emitting device of the comparative example and the example was measured, the output of the example was improved by 2% from the output of the comparative example. Note that the voltage necessary for flowing a current in the forward direction to the light emitting element, that is, the voltage necessary for the light emitting element to emit light (forward voltage drop) was the same.

(Third embodiment)
The semiconductor light emitting device according to the third embodiment of the present invention is different in that the DBR provided in the light reflecting film 20 is replaced with the DBR 25a shown in FIG. 21A instead of the DBR 25 shown in FIG. Since other configurations are the same as those of the semiconductor light emitting device according to the first or second embodiment, a plan view is omitted. The DBR 25a shown in FIG. 21A is different from the DBR 25 shown in FIG. 3 in that the stacking order of the low refractive index layer 251 and the high refractive index layer 252 is changed. For example, when the low-refractive index layer 251 is formed of SiO ₂ and the high-refractive index layer 252 is formed of Nb ₂ O ₅ , the DBR 25a is, for example, (SiO ₂ / Nb ₂ O ₅ ) _n (where n is a natural number). FIG. 21A illustrates the case where n = 3.

  An example of a method for forming the metal film 26 in the light reflecting film 20 will be described with reference to FIG. The metal film 26 can be formed by the following steps S10, S20, and S30.

  In step S10, as shown in FIG. 21A, a resist 310 is formed on a part of the surface of the DBR 25a. The resist 310 has a collar portion (overhang) 311. The collar part 311 is produced by a conventionally known method. For example, it can be manufactured by the following steps S11, S12, and S13 using an inverted negative resist. Here, the reverse negative resist has a property that the exposed portion is dissolved. Also, the reversal negative resist has the property that, when the reversal process is performed before development, composition change (cross-linking) due to heat treatment occurs in the lighted part, and the lighted part remains by development. ing.

(S11) An inverted negative resist is formed on the surface of the DBR 25a, and initial exposure is performed using a pattern that masks a portion that does not leave the resist after development. At this time, the reflected light from the surface of the DBR 25a hits the mask portion of the inverted negative resist.
(S12) An inversion process is performed. That is, reverse baking (reversal baking) is performed. This inverts the properties of the portion of the inverted negative resist that was not masked.
(S13) Whole surface exposure is performed. By development, the mask portion of the reverse negative resist is removed, and the unmasked portion remains. In addition, the portion exposed to the reflected light from the surface of the DBR 25a in step S11 is removed by the development, and the collar portion 311 is produced.

  Here, the degree of reverse taper of the flange 311 depends on the refractive index of the surface material forming the resist 310. The DBR 25 a is preferable because the final layer is the high refractive index layer 252 and the flange 311 can be easily formed as compared with the case where the final layer is the low refractive index layer 251.

Subsequent to step S10, in step S20, as shown in FIG. 21B, a metal film material (for example, AlCu alloy) 320 is formed on the surface of the DBR 25a from the top of the resist 310 using a sputtering method. At this time, the metal film material 320 does not adhere under the resist 310. However, the metal film material 320 adheres under the flange 311 and the tip of the portion that becomes the metal film has a tapered shape.
In step S30, as shown in FIG. 21C, the resist 310 is removed by a conventionally known removal method such as cleaning with a strong alkaline solution or peeling with a resist peeling device.

  If the metal film is formed using a resist in which the flange portion 311 is not formed, burrs are generated by removing the thick resist after the metal film material is attached. On the other hand, when the resist 310 having the flange 311 is used, generation of burrs can be suppressed when the resist 310 is removed after the metal film material is attached.

(Fourth embodiment)
The semiconductor light emitting device according to the fourth embodiment of the present invention is different in that the position of the second through hole 22 shown in FIG. 2 is changed, and other configurations are the semiconductors according to the first to third embodiments described above. Since it is the same as a light emitting element, a plan view is omitted. In FIG. 2, the semiconductor light emitting device 1 including the second through-hole 22 under the p-side pad electrode 52 is illustrated, but may be provided under the n-side pad electrode 51. When the shape of the semiconductor light emitting element 1 is a rectangle when viewed from the electrode surface side, a plurality of the second through holes 22 may be provided around the rectangle. The periphery of the rectangle may be on the n-side pad electrode 51 side. You may provide the 2nd through-hole 22 in a rectangular periphery and a corner. When the element shape viewed from the electrode surface side is a circle or polygon other than a rectangle, the periphery of the element represents a line outside the circle or polygon, and the second through hole 22 is provided at this position. The position of the second through hole 22 may not be the position of the periphery or corner of the element as long as it is away from the recess 7 and does not substantially affect current diffusion.

  Each of the embodiments described above exemplifies a semiconductor light emitting element for embodying the technical idea of the present invention, and the present invention is not limited to these. Moreover, this specification does not specify the member shown by the claim as the member of each embodiment at all. The dimensions, materials, shapes, relative arrangements, and the like of the components described in each embodiment are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing.

1, 1A Semiconductor light emitting device 2 Substrate 3 Semiconductor structure 4 N-side semiconductor layer (first semiconductor layer)
5 active layer 6 p-side semiconductor layer (second semiconductor layer)
7 Concave 11, 12 Translucent conductive film 20 Light reflective film 21 First through hole 22 Second through hole 23 Third through hole 24 First insulating film 25 DBR (distributed Bragg reflector)
251 Low refractive index layer 252 High refractive index layer 26 Metal film 27 Second insulating film 31, 31a, 31b N-side electrode layer (first electrode)
32 p-side electrode layer (second electrode)
33 Anchor opening (through hole)
40 protective film 41 n-side opening (through hole)
42 p-side opening (through hole)
51 n-side pad electrode (first pad electrode)
52, 52A p-side pad electrode (second pad electrode)
53 cutout portion 61 conducting portion 62 non-conducting portion 101 first region 102 second region 103 curved surface

Claims (8)

A semiconductor structure comprising a first semiconductor layer and a second semiconductor layer provided in a region on the first semiconductor layer;
A first electrode provided in another region on the first semiconductor layer;
A second electrode provided on the second semiconductor layer;
A semiconductor light emitting device comprising a light reflecting film covering the semiconductor structure,
The light reflecting film has an insulating film provided on the semiconductor structure, and a metal film provided on the insulating film,
The first electrode is provided so as to overlap the light reflection film at a peripheral portion thereof, and overlaps the insulating film exposed from the metal film rather than a region overlapping the metal film. A semiconductor light emitting element, wherein a region is disposed closer to the semiconductor structure.   2. The semiconductor light emitting element according to claim 1, wherein the first electrode is formed so that a film thickness thereof becomes thinner toward an end in a region overlapping and facing the metal film.   3. The semiconductor light emitting element according to claim 1, wherein a surface of the first electrode facing the metal film is curved in a concave shape in a region overlapping the metal film. 4.   The second electrode is provided so as to overlap the light reflecting film at an outer peripheral end portion of the semiconductor structure, and the second electrode is exposed from the metal film rather than a region overlapping the metal film. 4. The semiconductor light emitting element according to claim 1, wherein a region facing and overlapping the insulating film is disposed closer to the semiconductor structure. 5.   The semiconductor light emitting element according to claim 1, wherein the insulating film is a dielectric multilayer film. The light reflecting film is
From the semiconductor structure side,
A distributed Bragg reflector as the insulating film;
The metal film laminated on the distributed Bragg reflector;
A second insulating film laminated on the metal film,
5. The semiconductor light emitting device according to claim 1, wherein the first electrode is extended through the second insulating film so as to overlap an end portion of the metal film. 6. element.   The semiconductor light emitting element according to claim 6, wherein an end portion of the metal film is covered with the distributed Bragg reflector and the second insulating film.   The metal film of the light reflecting film extends from one region on the second semiconductor layer together with the insulating film to a part of another region on the first semiconductor layer. Item 8. The semiconductor light-emitting device according to any one of Items 1 to 7.