JP2003110139A - Nitride semiconductor light emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nitride semiconductor light emitting element which obtains a square shape light emitting region and which can effectively prevent optical unevenness. SOLUTION: This nitride semiconductor light emitting element is a nitride semiconductor light emitting element for fetching light from a sapphire substrate 1 side. The emitting element comprises an n-type contact layer 3 formed on the sapphire substrate 1, a light emitting layer 4 formed on the contact layer 3, a p-type contact layer 7 formed on the emitting layer 4, a stripe-like groove 80 for exposing the part of the layer 3 and dividing the layer 3 into a substantially square shape protrusion 11 and a substantially square shape protrusion 12 including one side of a chip, a p-type side electrode 8 formed on the protrusion 11 of the layer 7, and an n-type side electrode 9 formed in the groove 80 connected to the layer 3 and rising over on the part of the protrusion 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitride semiconductor light emitting device, and more particularly to a nitride semiconductor light emitting device that extracts light from a substrate side or an electrode side.

[0002]

2. Description of the Related Art Conventionally, GaN and I have been used as blue light emitting devices.
General formula In _x Al _y Ga _1-XY N (0 ≦ X <1, 0 ≦ Y <1) such as nGaN, AlGaN and InAlGaN
A light emitting device using a nitride-based semiconductor represented by is known. Among the conventional light emitting devices using a nitride semiconductor as described above, a nitride semiconductor light emitting device (LED) that extracts light from the substrate side or the electrode side is disclosed in Japanese Patent Laid-Open No. 11-126.
It is disclosed in Japanese Patent Laid-Open No. 923 and Japanese Patent Laid-Open No. 10-223930.

FIG. 17 shows the above-mentioned Japanese Patent Laid-Open No. 11-126923.
FIG. 6 is a cross-sectional view schematically showing a nitride-based semiconductor light emitting device (LED) according to a conventional example disclosed in Japanese Patent Laid-Open Publication No. H11-242242. Figure 1
7, in a conventional nitride-based semiconductor light emitting device 160, a buffer layer 102, an n-type contact layer 103 and an n-type cladding layer 104 are formed on a sapphire substrate 101. In addition, the n-type cladding layer 104
Above the light emitting layer 105, the p-type cladding layer 106 and p
The mold contact layer 107 is formed.

A p-side electrode 108 is formed in a partial region on the upper surface of the p-type contact layer 107. Also,
Partial regions of the p-type contact layer 107, the p-type cladding layer 106, the light emitting layer 105, the n-type cladding layer 104, and the n-type contact layer 103 are removed by etching,
The groove 120 is formed. On the surface of the n-type contact layer 103 exposed at the bottom of the groove 120,
The n-side electrode 109 is formed. An insulating film 110 is formed on the surface of the element other than the area where the p-side electrode 108 and the n-side electrode 109 are formed. A wire 111 is bonded on the n-side electrode 109.

In a conventional nitride-based semiconductor light emitting device 160 having a structure as shown in FIG. 17, a p-type contact layer 1 adjacent to an exposed surface of the n-type contact layer 103 is provided.
It is separated by cutting a part including a part of 07. FIG. 18 is a cross-sectional view for explaining a process of separating a nitride-based semiconductor light emitting device according to a conventional example. Figure 1
As shown in FIG. 8, when the nitride-based semiconductor light emitting device 160 according to the conventional example is separated, the protective sheet 161 is formed by using the breaker lower blade 163 and the breaker upper blade 164.
-Based semiconductor light emitting device 1 between the adhesive sheet 162 and the adhesive sheet 162
After the separation groove 165 is formed in the groove 60, a crack is advanced along the separation groove 165 to separate the crack.

FIG. 19 shows the above-mentioned Japanese Unexamined Patent Publication No. 10-223930.
FIG. 20 is a cross-sectional view showing a conventional nitride-based semiconductor light-emitting device disclosed in Japanese Patent Publication No. JP-A-2003-264, and FIG. 20 is a plan view corresponding to FIG. Referring to FIGS. 19 and 20,
In another conventional nitride-based semiconductor light emitting device, an n-type contact layer 152, a light emitting layer 153, and a p-type contact layer 154 are formed on a sapphire substrate 151. A p-side electrode 155 is formed in a partial region on the upper surface of the p-type contact layer 154. Further, the p-type contact layer 154, the light-emitting layer 153, and a partial region of the n-type contact layer 152 are removed by etching, and p
A columnar convex portion composed of the mold contact layer 154, the light emitting layer 153, and the n-type contact layer 152 is formed.
The n-type contact layer 152 is formed around the cylindrical protrusion.
Is exposed. Further, the n-side electrode 156 is formed so as to cover a part of the exposed surface of the n-type contact layer 152 and the upper surface and the side surface of the columnar convex portion. In addition, in a partial region on the upper surface of the p-type contact layer 154,
A p-side electrode 155 that also serves as a pad electrode for wire bonding is formed, and an n-side electrode 156 is formed.
A wire 157 is bonded on the top.

[0007]

The nitride-based semiconductor light-emitting device according to the conventional example shown in FIG. 17 and the nitride-based semiconductor light-emitting device according to another conventional example shown in FIGS. 19 and 20 have the following structure. There was such a problem.

First, in the nitride-based semiconductor light emitting device according to the conventional example shown in FIG. 17, the wire 1 is attached to the n-side electrode 109.
The groove portion 120 to which 11 is bonded needs to be formed to have a relatively large width in order to prevent an electrical short circuit. Therefore, in order to miniaturize the device, the p-type contact layer 1 adjacent to the groove 120 that does not contribute to light emission is provided.
It is necessary to make the width of the convex portion including 07 as small as possible.

However, if the width of the convex portion including the p-type contact layer 107 that does not contribute to light emission is reduced, then FIG.
In the step of separating the element chip shown in (1), there is a disadvantage that the convex portion including the p-type contact layer 107 that does not contribute to light emission is chipped and does not remain. In particular, the sapphire substrate 101
This is a hexagonal crystal having high strength and no cleavage in the direction of the end face of the element, so this problem is likely to occur. Therefore, the nitride-based semiconductor light emitting device according to the conventional example shown in FIG. 17 has a problem in that the yield in the device chip separation step is reduced.

In the conventional nitride-based semiconductor light-emitting device shown in FIGS. 19 and 20, the p-type contact layer 154, the light-emitting layer 153 and the n-type contact layer 1 are used.
Since the columnar convex portion is formed by removing 52 by etching, the p-type contact layer 154 to which the p-side electrode 155 is connected does not have a square shape. There was an inconvenience that it was difficult to obtain. Therefore, when a plurality of elements are arranged on a plane and a planar light source is formed, there is a problem that light unevenness occurs. There is also a problem in that light unevenness occurs due to a bonding wire (not shown) connected to the p-side electrode 155.

Further, in the conventional nitride-based semiconductor light emitting device shown in FIGS. 19 and 20, when the n-side electrode 156 is formed so as to cover the upper surface and the side surface of the cylindrical protrusion, Advanced step coverage thin film forming technology is required. Therefore, conventionally, there has been a problem that the process of forming the n-side electrode 156 is complicated.

The present invention has been made to solve the above problems, and one object of the present invention is to:
It is an object of the present invention to provide a nitride-based semiconductor light emitting device capable of obtaining a rectangular light emitting region and effectively preventing light unevenness.

Another object of the present invention is to provide a nitride semiconductor light emitting device capable of improving the yield in the device chip separating process.

[0014]

In order to achieve the above object, a nitride semiconductor light emitting device according to one aspect of the present invention is a nitride semiconductor light emitting device for extracting light from a substrate side or an electrode side. A first conductive type first nitride-based semiconductor layer formed on the substrate, a light emitting layer formed on the first nitride based semiconductor layer, and a second conductive type second nitride formed on the light emitting layer. The second nitride-based semiconductor layer and a portion of the first nitride-based semiconductor layer are exposed, and the second nitride-based semiconductor layer includes a substantially rectangular first region and one side of the chip. A stripe-shaped groove for dividing into a rectangular second area, a first electrode formed on the first area of the second nitride-based semiconductor layer, and a first nitride-based groove in the groove. A second electrode connected to the semiconductor layer and formed so as to ride on a part of the second region; It is provided.

In the nitride-based semiconductor light-emitting device according to this one aspect, as described above, the second nitride-based semiconductor layer is substantially composed of the substantially rectangular first region and one side of the chip. By providing the stripe-shaped groove portion for dividing into the second rectangular region, a substantially rectangular light emitting region can be obtained from the first region. This makes it possible to effectively prevent light unevenness. In the groove, the first
The second semiconductor layer is connected to the nitride-based semiconductor layer and is mounted on a part of the rectangular second region including one side of the chip.
By forming the electrode, for example, a cylindrical second
Unlike the case where the second electrode is formed so as to cover the upper surface and the side surface of the region, an advanced step coverage thin film forming technique or the like is not required, so that the second electrode can be easily formed. Further, by forming the second electrode so as to ride over a part of the second region, it is possible to guide the progress direction of the crack to a place where the second electrode is not formed when the element chip is separated. it can. As a result, the yield in the element chip separation process can be improved. Further, by forming the second electrode so as to ride on a part of the second region, the heights of the second electrode and the first electrode are equalized, so that the chip is tilted during face-down mounting or the like. Can be prevented.

In the nitride-based semiconductor light emitting device according to the above aspect, preferably, the first electrode has a substantially rectangular region over substantially the entire region of the first region of the second nitride-based semiconductor layer. Is formed in. According to this structure, the current applied to the first electrode can flow through almost the entire light emitting region, and uniform light emission can be obtained.

In the nitride-based semiconductor light-emitting device according to the above aspect, it is preferable that a lead-out electrode that is connected to the end of the first electrode on the groove side and is formed so as to ride on a part of the second region is further provided. Prepare If the extraction electrode is provided in this way, it is not necessary to form an electrode for wire bonding on the first region, and thus light on the first region formed in the substantially rectangular region is blocked. The area can be reduced. This makes it possible to obtain a rectangular light emitting region in which light unevenness is suppressed. In this case, the lead electrode and the second electrode are preferably wire-bonded on the second region. According to this structure, since the wire is connected on the second region near the outer circumference, the wire can be arranged at a position where light is not blocked. This also makes it possible to prevent light unevenness from occurring.

The nitride-based semiconductor light-emitting device according to the above aspect preferably further includes a pad electrode formed on one side of the first electrode opposite to the groove, and having a substantially rectangular shape. . According to this structure, since the first electrode other than the region where the pad electrode is formed is also substantially rectangular, a rectangular light emitting region can be easily obtained. Further, by providing a substantially rectangular pad electrode on one side opposite to the groove portion of the first electrode, the second electrode formed so as to ride on a part of the second region from the pad electrode. The current can be uniformly diffused when the current is flown toward. As a result, it is possible to prevent light unevenness from occurring.

In the above nitride semiconductor light emitting device,
Preferably, the first electrode and the second electrode are provided on substantially the same flat surface. According to this structure, the heights of the second electrode and the first electrode can be easily made equal to each other, so that the chip can be prevented from tilting during face-down mounting or the like.

In the above nitride semiconductor light emitting device,
Preferably, the first nitride-based semiconductor layer includes an n-type first nitride-based semiconductor layer, and the second nitride-based semiconductor layer includes a p-type second nitride-based semiconductor layer. With this configuration,
Ohmic contacts can be obtained between the n-type first nitride semiconductor layer and the second electrode and between the p-type second nitride semiconductor layer and the first electrode.

In the above nitride semiconductor light emitting device,
Preferably, the first electrode may include an electrode film having a thickness that allows light to pass therethrough, or may be formed via a gap that allows light to pass therethrough. According to this structure, light can be easily extracted from the first electrode side.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIGS. 1 and 2 show a nitride-based semiconductor light emitting device (LE) according to a first embodiment of the present invention.
FIG. 6 is a cross-sectional view and a plan view showing D). In the first embodiment, an example in which the present invention is applied to a nitride-based semiconductor light emitting device (LED) that extracts light from the substrate side will be described.

First, the structure of the nitride-based semiconductor light-emitting device (LED) according to the first embodiment will be described with reference to FIGS. 1 and 2. In the nitride-based semiconductor light-emitting device (LED) according to the first embodiment, an undoped AlN layer having a film thickness of about 2.5 nm and an undoped GaN layer having a film thickness of about 2.5 nm are formed on the sapphire substrate 1. A buffer layer 2 made of a multilayer film formed by alternately laminating four cycles and an n-type contact layer 3 made of n-type GaN having a film thickness of about 5 μm are formed. Undoped Ga having a film thickness of about 5 nm is formed on the n-type contact layer 3.
A light emitting layer 4 having a superlattice structure in which a barrier layer made of N and a well layer made of undoped GaInN having a film thickness of about 5 nm are alternately laminated is formed. The sapphire substrate 1 is an example of the “substrate” in the present invention, and the n-type contact layer 3 is the “first nitride-based semiconductor layer” in the present invention.
Is an example.

On the light emitting layer 4, a protective layer 5 made of undoped GaN having a film thickness of about 10 nm, about 0.1 is formed.
A p-type clad layer 6 made of p-type AlGaN having a thickness of 5 μm, and a p-type G having a thickness of about 0.3 μm
A p-type contact layer 7 made of aN is formed. The p-type contact layer 7 is an example of the “second nitride-based semiconductor layer” in the present invention.

Here, in the first embodiment, the p-type contact layer 7, the p-type cladding layer 6, the protective layer 5, the light emitting layer 4 and the n-type.
A partial region of the mold contact layer 3 is removed by etching to form a stripe-shaped groove portion 80 penetrating to both ends. On both sides of the groove 80, convex portions 11 and 12 formed of the p-type contact layer 7, the p-type cladding layer 6, the protective layer 5, the light emitting layer 4 and the n-type contact layer 3 are formed. The convex portion 11 and the convex portion 12 are the groove portion 80.
It is electrically separated by. As shown in FIG. 2, the upper surfaces of the protrusions 11 and 12 are formed in a substantially rectangular shape, and the protrusion 12 has about 4
It is formed to have a width of 0 μm to about 80 μm. The protrusion 11 is an example of the “first region” in the present invention, and the protrusion 12 is an example of the “second region” in the present invention.

Then, a Ni film having a film thickness of about 100 nm and an Au film having a film thickness of about 800 nm are formed on almost the entire upper surface of the p-type contact layer 7 constituting the convex portion 11.
A square p-side electrode 8 composed of a film is formed. The p-side electrode 8 is an example of the “first electrode” in the present invention.

Further, a partial area on the convex portions 11 and 12, a partial area on the bottom of the groove portion 80, and the groove portion 8 of the convex portion 12 are provided.
An insulating film 10 made of SiO ₂ having a film thickness of about 200 nm is formed so as to cover the side surface on the 0 side. Then, it contacts a part of the surface of the n-type contact layer 3 exposed at the bottom of the groove 80, covers the insulating film 10 formed on the side surface of the groove 80, and covers a part of the protrusion 12. The n-side electrode 9 is formed so as to ride up. The n-side electrode 9 includes, from the bottom, a Ti film having a film thickness of about 1 nm, a Pt film having a film thickness of about 99 nm, and a Pt film of about 8 nm.
It is composed of an Au film having a film thickness of 00 nm. The n-side electrode 9 is an example of the "second electrode" in the present invention. The p-side electrode 8 and the n-side electrode 9 are formed so as to have substantially the same height.

By attaching the nitride-based semiconductor light-emitting device (LED) of the first embodiment having the structure shown in FIG. 1 to the submount (heat dissipation base) 13 from the p-side electrode 8 and the n-side electrode 9 side. When face down mounting is performed, the structure is as shown in FIG. Referring to FIG. 3, metal layers 14 and 15 are formed on submount 13. Fusing materials 16 and 17 are provided on the metal layers 14 and 15, respectively. In the nitride-based semiconductor light-emitting device (LED) of the first embodiment, the p-side electrode 8 and the metal layer 14 are fused by the fusion material 16 with the p-side electrode 8 and the n-side electrode 9 side of the surface facing downward. At the same time, the n-side electrode 9 and the metal layer 15 are fused by the fusion material 17. The wire 18 is bonded to a region of the metal layer 14 where the fusion material 16 is not formed, and the wire 19 is bonded to a region of the metal layer 15 where the fusion material 17 is not formed. Has been done.

By performing the face-down mounting in this manner, the nitride semiconductor light emitting device (LED) of the first embodiment, which takes out light from the transparent sapphire substrate 1 side, is formed.

In the first embodiment, as described above, the protrusions 11 are formed by providing the substantially rectangular protrusions 11 and the stripe-shaped groove portions 80 for forming the protrusions 12.
The p-side electrode 8 formed over almost the entire upper region can be formed in the rectangular region. This makes it possible to obtain a substantially rectangular light emitting region, so that it is possible to effectively prevent light unevenness from occurring when forming a planar light source from a plurality of elements.

In the first embodiment, p having a relatively large resistivity (about 0.1 Ω · cm to 10 Ω · cm).
On the p-type contact layer 7 made of p-type GaN and having a thickness (about 900 nm) sufficiently low resistance as a current path.
By forming the, the current applied to the p-side electrode 8 can be made to flow through almost the entire light emitting region, and uniform light emission can be obtained.

Further, in the first embodiment, as described above,
By connecting to the n-type contact layer 3 at the bottom of the groove 80 and forming the n-side electrode 9 so as to ride on a part of the convex portion 12, the upper surface of the cylindrical convex portion as shown in FIG. Unlike the case where the n-side electrode is formed so as to cover the side surface and the side surface, since the step coverage thin film is formed from one direction, no advanced forming technique is required.
The n-side electrode 9 can be easily formed.

In the first embodiment, as described above,
By forming the n-side electrode 9 so as to ride on a part of the convex portion 12 that does not contribute to light emission, when the element chips are separated, the progress of cracks is guided to the place where the n-side electrode 9 is not formed. can do. As a result, the yield in the element chip separation process can be improved.

Further, in the first embodiment, as described above,
By forming the n-side electrode 9 so as to ride on a part of the convex portion 12, the heights of the n-side electrode 9 and the p-side electrode 8 can be made substantially equal. This can prevent the chip from tilting during face-down mounting.

In the first embodiment, as described above,
By providing the stripe-shaped groove portion 80, the convex portion 1
1 and 12 can be divided into simple squares.
As a result, the metal layers 14 and 15 on the submount 13 used for face-down mounting can also simply have a structure in which two poles are separated. Thereby, the submount 13 can be downsized. In addition, a nitride-based semiconductor light-emitting device (LED) has a simple bipolar structure.
Since it is possible to easily align the p-side electrode 8 and the n-side electrode 9 with the metal layers 14 and 15 of the submount 13, it is possible to improve the yield in the assembly process during face-down mounting. .

(Second Embodiment) FIGS. 4 and 5 show a nitride-based semiconductor light emitting device (LE) according to a second embodiment of the present invention.
FIG. 6 is a cross-sectional view and a plan view showing D). In the second embodiment, an example will be described in which, instead of the stripe-shaped groove portion 80 that penetrates to both end portions of the first embodiment, a groove portion 81 that does not penetrate to both end portions is formed. Hereinafter, a detailed description will be given with reference to FIGS. 4 and 5.

In the nitride-based semiconductor light emitting device (LED) according to the second embodiment, about 2.5 μm is provided on the sapphire substrate 21.
an undoped AlN layer having a thickness of nm and a thickness of about 2.5 n
A buffer layer 22 made of a multilayer film formed by alternately stacking four periods of undoped GaN layers having a thickness of m and an n-type contact layer 23 made of n-type GaN having a thickness of about 5 μm are formed. Has been done. On the n-type contact layer 23, undoped GaN having a film thickness of about 5 nm
A light-emitting layer 24 having a superlattice structure is formed by alternately stacking a barrier layer made of and a well layer made of undoped GaInN having a thickness of about 5 nm. The sapphire substrate 21 is an example of the “substrate” in the present invention, and n
The mold contact layer 23 is an example of the “first nitride-based semiconductor layer” in the present invention.

On the light emitting layer 24, a protective layer 25 made of undoped GaN having a film thickness of about 10 nm and p made of p-type AlGaN having a film thickness of about 0.15 μm.
A type clad layer 26 and a p-type contact layer 27 made of p-type GaN having a film thickness of about 0.3 μm are formed. The p-type contact layer 27 is an example of the "second nitride semiconductor layer" in the present invention.

Partial regions of the p-type contact layer 27, the p-type cladding layer 26, the protective layer 25, the light emitting layer 24 and the n-type contact layer 23 are removed by etching,
A groove 81 is formed. On both sides of this groove 81,
p-type contact layer 27, p-type cladding layer 26, protective layer 2
5, convex portions 31 and 32 composed of the light emitting layer 24 and the n-type contact layer 23 are formed.

Here, in the second embodiment, the convex portion 31 and the convex portion 32 are the unetched regions (p-type contact layer 27, p-type cladding layer 26, and
Protective layer 25, light emitting layer 24 and n-type contact layer 23)
Are linked by. That is, in the second embodiment,
The convex portion 31 and the convex portion 32 are not electrically separated by the groove portion 81 but are electrically connected. As shown in FIG. 5, the upper surfaces of the convex portions 31 and 32 are formed to have a substantially rectangular shape, and the convex portion 32 is formed.
Are formed to have a width of about 40 μm to about 80 μm. The protrusion 31 is an example of the “first region” in the present invention, and the protrusion 32 is an example of the “second region” in the present invention.

Then, a Ni film having a film thickness of about 100 nm and an A film having a film thickness of about 800 nm are formed over almost the entire area of the upper surface of the p-type contact layer 27 constituting the convex portion 31.
A square p-side electrode 28 including a u film is formed. The p-side electrode 28 is an example of the “first electrode” in the present invention.

In addition, a partial area on the convex portion 31 and the groove portion 81
SiO ₂ having a film thickness of about 200 nm so as to cover a partial region on the bottom of the groove, the non-etched regions at both ends of the groove 81, and the side surface and the upper surface of the protrusion 32 on the groove 81 side. An insulating film 30 made of is formed. Then, the insulating film 30 contacting a part of the surface of the n-type contact layer 23 exposed at the bottom of the groove 81, covering the insulating film 30 formed on the side surface of the convex portion 32, and insulating film on the convex portion 32. N-side electrode 2 so as to ride on a part of 30
9 is formed. The n-side electrode 29 is composed of a Ti film having a film thickness of about 1 nm, a Pt film having a film thickness of about 99 nm, and an Au film having a film thickness of about 800 nm from the bottom. The n-side electrode 29 is an example of the “second electrode” in the present invention. Further, the upper surface of the n-side electrode 29 is arranged at a position higher than the upper surface of the p-side electrode 28 by the thickness of the insulating film 30 (about 200 nm).
Since 1 and 32 have a height of about 1 μm (1000 nm) or more, the difference in height between the p-side electrode 28 and the n-side electrode 29 does not matter so much.

The nitride-based semiconductor light-emitting device (LED) of the second embodiment having the structure shown in FIG. 4 is submounted (heat dissipation base) 13 from the p-side electrode 28 and n-side electrode 29 sides.
When the face-down mounting is performed by mounting the structure on the substrate, a structure as shown in FIG. 6 is obtained. Referring to FIG. 6, metal layers 14 and 15 are formed on submount 13. On the metal layers 14 and 15, respectively,
Fusing materials 16 and 17 are formed. In the nitride-based semiconductor light emitting device (LED) of the second embodiment, the p-side electrode 28 and the metal layer 14 are fused by the fusing material 16 with the p-side electrode 28 and the n-side electrode 29 side of the surface facing downward. At the same time, the n-side electrode 29 and the metal layer 15 are fused by the fusion material 17. In addition, the fusing material 16 on the metal layer 14
The wire 18 is bonded to the region where the fusing material 17 is not formed, and the wire 19 is bonded to the region where the fusing material 17 on the metal layer 15 is not formed.

By performing the face-down mounting in this way, the nitride-based semiconductor light-emitting device (LED) of the second embodiment in which light is extracted from the transparent sapphire substrate 21 side.
Is formed.

In the second embodiment, as described above, the n-side electrode 29 is formed so as to ride over the convex portion 32 via the insulating film 30, so that the p-type contact layer 27 of the convex portion 32 is formed. Even when the projection 31 is electrically connected to the p-type contact layer 27, the n-side electrode 29 can be easily formed on the projection 32.

The other effects of the second embodiment are similar to those of the above-described first embodiment.

(Third Embodiment) FIGS. 7 to 9 show a nitride-based semiconductor light emitting device (LED) according to a third embodiment of the present invention.
FIG. 3 is a plan view and a cross-sectional view showing FIG. In addition, in FIG.
A cross section taken along line 200-200 of the nitride-based semiconductor light-emitting device (LED) of the third embodiment shown in FIG. 7 is shown, and FIG. 9 shows the nitride of the third embodiment shown in FIG. A cross section taken along line 300-300 of a physical semiconductor light emitting device (LED) is shown. In the third embodiment, an example will be described in which a p-side electrode is formed through a gap that allows light to pass therethrough and light is extracted from the p-side electrode side. Hereinafter, a detailed description will be given with reference to FIGS. 7 to 9.

In the nitride-based semiconductor light-emitting device (LED) according to the third embodiment, about 2.5 is formed on the sapphire substrate 41.
an undoped AlN layer having a thickness of nm and a thickness of about 2.5 n
A buffer layer 42 made of a multilayer film formed by alternately stacking four periods of an undoped GaN layer having a thickness of m and an n-type contact layer 43 made of n-type GaN having a thickness of about 5 μm are formed. Has been done. On the n-type contact layer 43, undoped GaN having a film thickness of about 5 nm
And a well layer made of undoped GaInN having a thickness of about 5 nm are alternately laminated to form a light emitting layer 44 having a superlattice structure. The sapphire substrate 41 is an example of the “substrate” in the present invention, and n
The mold contact layer 43 is an example of the “first nitride-based semiconductor layer” in the present invention.

On the light emitting layer 44, a protective layer 45 made of undoped GaN having a film thickness of about 10 nm and p made of p-type AlGaN having a film thickness of about 0.15 μm.
A type cladding layer 46 and a p-type contact layer 47 made of p-type GaN having a thickness of about 0.3 μm are formed. The p-type contact layer 47 is an example of the “second nitride-based semiconductor layer” in the present invention.

Partial regions of the p-type contact layer 47, the p-type cladding layer 46, the protective layer 45, the light emitting layer 44 and the n-type contact layer 43 are removed by etching,
Striped groove portions 82 are formed so as to penetrate to both ends. The p-type contact layer 4 is formed on both sides of the groove 82.
7, convex portions 54 and 55 formed of the p-type cladding layer 46, the protective layer 45, the light emitting layer 44, and the n-type contact layer 43 are formed. The upper surfaces of the protrusions 54 and 55 are formed to have a substantially rectangular shape, and the protrusion 55
Are formed to have a width of about 80 μm to about 120 μm. The convex portion 54 is the “first region” of the present invention.
The convex portion 55 is an example of the “second region” in the present invention.

Here, in the third embodiment, the convex portion 54
The p-side electrode in the form of a lattice formed of a Ni film having a film thickness of about 100 nm and an Au film having a film thickness of about 800 nm over almost the entire upper surface of the rectangular p-type contact layer 47 constituting the. 48 are formed. The lattice-shaped p-side electrode 48 is formed in a rectangular region as a whole. The p-side electrode 48 is the “first electrode” of the present invention.
Is an example.

Further, a partial area on the convex portion 54 and the groove portion 82
About 200 n so as to cover a partial area on the bottom of the ridge, a side surface of the convex portion 55 on the groove portion 82 side, and a partial area on the convex portion 55.
An insulating film 49 made of SiO ₂ having a film thickness of m is formed.

In the third embodiment, as shown in FIG. 8, the insulating film 49 connected to the end of the p-side electrode 48 on the groove 82 side and formed on the side surface and the bottom of the groove 82 is covered. , A Ti film having a thickness of about 1 nm and about 99 n so as to ride on a part of the insulating film 49 on the convex portion 55.
A p-side pad electrode 50 including a Pt film having a film thickness of m and an Au film having a film thickness of about 800 nm is formed. The p-side pad electrode 50 is an example of the “lead electrode” in the present invention.

Further, as shown in FIG. 9, while covering a partial region of the surface of the n-type contact layer 43 exposed at the bottom of the groove 82 and the insulating film 49 formed on the side surface of the protrusion 55, , A Ti film having a film thickness of about 1 nm and a film thickness of about 9 so as to ride on a part of the insulating film 49 on the convex portion 55.
An n-side electrode 51 including a Pt film having a film thickness of 9 nm and an Au film having a film thickness of about 800 nm is formed. The n-side electrode 51 is an example of the “second electrode” in the present invention.

When wire bonding is performed on the nitride semiconductor light emitting device (LED) of the third embodiment having the structure shown in FIGS. 7 to 9, the structure becomes as shown in FIGS. 10 to 12. Note that FIG. 11 shows a cross section taken along line 400-400 of the nitride-based semiconductor light-emitting device (LED) shown in FIG. 10, and FIG. 12 shows the nitride-based semiconductor shown in FIG. A cross section along line 500-500 of a light emitting device (LED) is shown. 10 to 12, a wire 52 is bonded on the p-side pad electrode 50 on the convex portion 55. In addition, the n-side electrode 5 on the convex portion 55
A wire 53 is bonded onto the wire 1.

By performing the wire bonding as described above, the nitride-based semiconductor light-emitting device (L) of the third embodiment in which light is extracted from the gap formed between the p-side electrodes 48.
ED) is formed.

In the third embodiment, as described above, the p-side pad electrode 50 is connected to the end of the p-side electrode 48 on the groove portion 82 side, and is also laid on a part of the insulating film 49 on the convex portion 55. By thus forming, it is not necessary to form an electrode for wire bonding on the p-side electrode 48, and thus it is possible to reduce the light blocking area on the substantially rectangular convex portion 54. . This makes it possible to obtain a rectangular light emitting region in which light unevenness is suppressed.

Further, in the third embodiment, as described above,
Since the wires 52 and 53 are connected to each other on the convex portion 55 that does not contribute to light emission and is close to the outer circumference, the wires can be arranged at a position that does not block light. This also makes it possible to prevent light unevenness from occurring.

Further, in the third embodiment, as described above,
The p-side pad electrode 50 and the n-side electrode 51 have the same protrusion 5
By forming the wire 52 on the wire 5, the wires 52 and 53 can be bonded to the p-side pad electrode 50 and the n-side electrode 51 with a uniform pressure during wire bonding. As a result, a nitride-based semiconductor light emitting device (LE
The reliability of D) can be improved.

(Fourth Embodiment) FIGS. 13 and 14 show
FIG. 9 is a plan view and a cross-sectional view showing a nitride semiconductor light emitting device (LED) according to a fourth embodiment of the present invention. In addition,
FIG. 14 shows a cross section taken along line 600-600 of the nitride-based semiconductor light emitting device (LED) shown in FIG. In the fourth embodiment, the p-side pad electrode is formed on the thin p-side electrode having a light transmitting property, and p
An example of extracting light from the side electrode side will be described. Less than,
This will be described in detail with reference to FIGS. 13 and 14.

In the nitride-based semiconductor light emitting device (LED) according to the fourth embodiment, about 2.5 is formed on the sapphire substrate 61.
an undoped AlN layer having a thickness of nm and a thickness of about 2.5 n
A buffer layer 62 made of a multilayer film formed by alternately laminating four cycles of an undoped GaN layer having a thickness of m and an n-type contact layer 63 made of n-type GaN having a thickness of about 5 μm are formed. Has been done. Undoped GaN having a film thickness of about 5 nm is formed on the n-type contact layer 63.
A light emitting layer 64 having a superlattice structure is formed by alternately stacking a barrier layer made of and an undoped GaInN well layer having a thickness of about 5 nm. The sapphire substrate 61 is an example of the “substrate” in the present invention, and n
The mold contact layer 63 is an example of the “first nitride-based semiconductor layer” in the present invention.

On the light emitting layer 64, a protective layer 65 made of undoped GaN having a film thickness of about 10 nm, and p made of p-type AlGaN having a film thickness of about 0.15 μm.
A type clad layer 66 and a p-type contact layer 67 made of p-type GaN having a film thickness of about 0.3 μm are formed. The p-type contact layer 67 is an example of the "second nitride semiconductor layer" in the present invention.

Partial regions of the p-type contact layer 67, the p-type cladding layer 66, the protective layer 65, the light emitting layer 64 and the n-type contact layer 63 are removed by etching,
Striped groove portions 83 are formed so as to penetrate to both ends. The p-type contact layer 6 is formed on both sides of the groove 83.
7, convex portions 74 and 75 formed of the p-type cladding layer 66, the protective layer 65, the light emitting layer 64, and the n-type contact layer 63 are formed. The upper surfaces of the protrusions 74 and 75 are formed to have a substantially rectangular shape, and
Are formed to have a width of about 80 μm to about 120 μm. The convex portion 74 is the “first region” of the present invention.
The convex portion 75 is an example of the “second region” in the present invention.

Here, in the fourth embodiment, the convex portion 74
Ni having a film thickness of about 2 nm from the bottom over almost the entire upper surface of the rectangular p-type contact layer 67 forming the
A translucent p-side electrode 68 including a film, an Au film having a film thickness of about 4 nm, and a Ni film having a film thickness of about 1 nm is formed. Note that the p-side electrode 68 is the “first electrode” of the present invention.
It is an example of an "electrode".

Further, a partial area on the convex portion 74 and the groove portion 83
About 200 n so as to cover a partial area on the bottom of the ridge, a side surface of the convex portion 75 on the groove 83 side, and a partial area on the convex portion 75.
An insulating film 70 made of SiO ₂ having a thickness of m is formed.

A Ti film having a film thickness of about 1 nm, a Pt film having a film thickness of about 99 nm, and a film thickness of about 800 nm are provided along one side of the p-side electrode 68 opposite to the groove 83. A substantially rectangular p-side pad electrode 71 formed of the Au film is formed. The p-side pad electrode 71
Is an example of the "pad electrode" in the present invention.

In addition, the partial area of the surface of the n-type contact layer 63 exposed at the bottom of the groove 83 and the insulating film 70 formed on the side surface of the convex portion 75 are covered and the insulating on the convex portion 75 is performed. Approximately 1 to ride over a portion of the membrane 70
An n-side electrode 69 including a Ti film having a film thickness of nm, a Pt film having a film thickness of about 99 nm, and an Au film having a film thickness of about 800 nm is formed. The n-side electrode 6
9 is an example of the "2nd electrode" of this invention.

Wire-bonding the nitride semiconductor light emitting device (LED) of the fourth embodiment having the structure shown in FIGS. 13 and 14 results in the structure shown in FIGS. 15 and 16. In addition, in FIG. 16, 700-700 of the nitride-based semiconductor light-emitting device (LED) shown in FIG.
A cross section along the line is shown. 15 and 16, wire 72 is bonded on p-side pad electrode 71 on p-side electrode 68. A wire 73 is bonded on the n-side electrode 69 on the convex portion 75.

By performing wire bonding in this manner, a nitride semiconductor light emitting device (LED) according to the fourth embodiment is formed in which light is extracted from the translucent p-side electrode 68 side.

In the fourth embodiment, as described above, the p-side pad electrode 71 having a substantially rectangular shape is provided along one side of the p-side electrode 68 on the side opposite to the groove portion 83.
P-side electrode 68 other than the region where the side pad electrode 71 is formed
Since it is formed in a substantially rectangular region, it is possible to easily obtain a rectangular light emitting region.

In the fourth embodiment, as described above,
By providing a substantially rectangular p-side pad electrode 71 along one side of the p-side electrode 68 on the side opposite to the groove portion 83, the p-side pad electrode 71 is mounted on a part of the convex portion 75. When a current is made to flow toward the n-side electrode 69 formed on, the current can be diffused uniformly. As a result, it is possible to prevent light unevenness from occurring.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and includes meaning equivalent to the scope of claims for patent and all modifications within the scope.

For example, in the above embodiment, the insulating film made of SiO ₂ is used, but the present invention is not limited to this, and Si is used.
Other insulating and translucent materials such as N may be used.

Further, in the third embodiment, the lattice-shaped p
Although the side electrode is formed, the present invention is not limited to this, and a stripe-shaped, comb-shaped or meandered p-side electrode may be formed.

Further, in the third and fourth embodiments described above,
Although the p-side electrode including the Ni film and the Au film is formed, the present invention is not limited to this, and a metal film such as Ni, Au, Al, or Pd may be formed to have a film thickness of 0.005 μm to 0.2 μm. The p-side electrode may be formed by vapor deposition.

Further, in the above-mentioned embodiment, an LED is taken as an example of the nitride-based semiconductor light-emitting device of the present invention, but the present invention is not limited to this, and a nitride-based semiconductor light-emitting device other than the LED is used. It is also applicable to.

[0078]

As described above, according to the present invention, it is possible to provide a nitride-based semiconductor light emitting device that can obtain a rectangular light emitting region and can effectively prevent light unevenness.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a nitride semiconductor light emitting device (LED) according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a nitride semiconductor light emitting device (LED) according to a first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a state in which a nitride semiconductor device (LED) according to the first embodiment of the present invention is face-down mounted.

FIG. 4 is a cross-sectional view showing a nitride semiconductor light emitting device (LED) according to a second embodiment of the present invention.

FIG. 5 is a plan view showing a nitride semiconductor light emitting device (LED) according to a second embodiment of the present invention.

FIG. 6 is a sectional view showing a state in which a nitride-based semiconductor device (LED) according to a second embodiment of the present invention is face-down mounted.

FIG. 7 is a plan view showing a nitride semiconductor light emitting device (LED) according to a third embodiment of the present invention.

FIG. 8 is a sectional view showing a nitride-based semiconductor light emitting device (LED) according to a third embodiment of the present invention.

FIG. 9 is a sectional view showing a nitride semiconductor light emitting device (LED) according to a third embodiment of the present invention.

FIG. 10 is a plan view showing a state in which a nitride semiconductor device (LED) according to a third embodiment of the present invention is wire-bonded.

FIG. 11 is a cross-sectional view showing a state in which a nitride semiconductor device (LED) according to a third embodiment of the present invention is wire-bonded.

FIG. 12 is a sectional view showing a state in which a nitride semiconductor device (LED) according to a third embodiment of the present invention is wire-bonded.

FIG. 13 is a plan view showing a nitride semiconductor light emitting device (LED) according to a fourth embodiment of the present invention.

FIG. 14 is a sectional view showing a nitride-based semiconductor light emitting device (LED) according to a fourth embodiment of the present invention.

FIG. 15 is a plan view showing a state in which a nitride semiconductor device (LED) according to a fourth embodiment of the present invention is wire-bonded.

FIG. 16 is a sectional view showing a state in which a nitride semiconductor device (LED) according to a fourth embodiment of the present invention is wire-bonded.

FIG. 17 is a cross-sectional view showing a conventional nitride semiconductor light emitting device (LED).

FIG. 18 is a cross-sectional view illustrating a step of cleaving a conventional nitride-based semiconductor light emitting device.

FIG. 19 is a cross-sectional view showing a conventional nitride semiconductor light emitting device (LED).

FIG. 20 is a plan view showing a conventional nitride semiconductor light emitting device (LED).

[Explanation of symbols]

1, 21, 41, 61 Sapphire substrate (substrate) 3, 23, 43, 63 n-type contact layer (first nitride semiconductor layer) 4, 24, 44, 64 Light-emitting layer 7, 27, 47, 67 p-type Contact layer (second nitride semiconductor layer) 8, 28, 48, 68 p-side electrode (first electrode) 9, 29, 51, 69 n-side electrode (second electrode) 11, 31, 54, 74 Convex portion (First region) 12, 32, 55, 75 Convex portion (second region) 50 p-side pad electrode (lead electrode) 52, 53, 72, 73 wire 71 p-side pad electrode (pad electrode) 80, 81, 82 , 83 groove

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasuhiko Nomura             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Toyozo Nishida             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. F-term (reference) 5F041 AA05 CA05 CA40 CA82 CA85                       CB03 CB13 DA07 DA09 DA19

Claims (9)

[Claims] 1. A nitride-based semiconductor light-emitting device that extracts light from a substrate side or an electrode side, wherein a first conductivity-type first nitride-based semiconductor layer formed on the substrate, and the first nitride. A light emitting layer formed on the light emitting semiconductor layer, a second conductivity type second nitride semiconductor layer formed on the light emitting layer, and exposing a part of the first nitride semiconductor layer, A stripe-shaped groove for dividing the second nitride-based semiconductor layer into a substantially rectangular first region and a substantially rectangular second region including one side of a chip; 2 a first electrode formed on a first region of the nitride-based semiconductor layer, and connecting to the first nitride-based semiconductor layer in the groove and riding on a part of the second region. A nitride-based semiconductor light-emitting device comprising the formed second electrode. 2. The first electrode according to claim 1, wherein the first electrode is formed in a substantially rectangular region over substantially the entire first region of the second nitride semiconductor layer. Nitride semiconductor light emitting device. 3. The nitride according to claim 1, further comprising an extraction electrode connected to an end of the first electrode on the groove side and formed so as to ride on a part of the second region. Physical semiconductor light emitting device. 4. The lead electrode and the second electrode are
The nitride-based semiconductor light emitting device according to claim 3, wherein wire bonding is performed on the second region. 5. The first electrode on the side opposite to the groove portion of the first electrode.
The nitride-based semiconductor light-emitting device according to claim 1, further comprising a pad electrode formed on a side and formed in a substantially rectangular shape. 6. The nitride-based semiconductor light-emitting device according to claim 1, wherein the first electrode and the second electrode are provided on substantially the same flat surface. 7. The first nitride-based semiconductor layer includes an n-type first nitride-based semiconductor layer, and the second nitride-based semiconductor layer includes a p-type second nitride-based semiconductor layer. The nitride-based semiconductor light-emitting device according to claim 1. 8. The nitride-based semiconductor light-emitting element according to claim 1, wherein the first electrode includes an electrode film having a thickness that allows light to pass therethrough. 9. The nitride-based semiconductor light emitting device according to claim 1, wherein the first electrode is formed through a gap that allows light to pass therethrough.