JP2004179491A - Nitride semiconductor light emitting element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nitride semiconductor light emitting element which has high light emission efficiency and high guide-out efficiency of emitted light. <P>SOLUTION: The nitride semiconductor light emitting element is equipped with a contact layer formed of a p-type nitride semiconductor, and has a p-side ohmic electrode formed partially on the contact layer except a light projection part. In the light emitting element, the p-type nitride semiconductor layer is modified by removing a metal layer after the metal layer has been formed of at least one substance selected from a group of Ni and Pt. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a nitride semiconductor light emitting device that emits light through a p-side contact layer.
[0002]
[Prior art]
A nitride semiconductor light emitting device capable of emitting light having a relatively short wavelength usually has a structure in which a predetermined nitride semiconductor layer is grown on an insulating substrate and n-type and p-type electrodes are formed on the semiconductor layer. Is formed, and light is emitted from the substrate side or the semiconductor side. In this nitride semiconductor light emitting device, a p-type contact layer is usually formed at a position farthest from the substrate. When light is emitted through the p-type contact layer, an electrode is formed as follows. ing.
For example, in Patent Document 1, when light emitted from a light emitting layer is emitted upward, a comb-shaped pattern as shown in FIG. 8B or a comb-shaped pattern shown in FIG. 8) is disclosed, and the comb-shaped electrode shown in FIG. 8B has a structure in which emitted light is extracted from an opening having no electrode. It is disclosed.
[0003]
[Patent Document 1]
JP-A-2000-174339 (paragraph 0005, FIG. 8 (b), FIG. 8 (c))
[0004]
[Problems to be solved by the invention]
However, in the conventional example using a transparent electrode, light is attenuated by the transparent electrode, and there is a certain limit in improving light extraction efficiency.
Further, in the conventional example in which light is emitted from the opening, current is difficult to be injected into the light-emitting layer immediately below the light-emitting opening because the resistance value of the p-type nitride semiconductor layer is large, which also results in luminous efficiency and There is a certain limit in improving the efficiency of extracting emitted light.
[0005]
Accordingly, an object of the present invention is to provide a nitride semiconductor light emitting device having high luminous efficiency and high light extraction efficiency.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a nitride semiconductor light emitting device according to the present invention includes a p-type contact layer made of a p-type nitride semiconductor, and is partially provided on the p-type contact layer except for a light emitting portion. In the nitride semiconductor light emitting device having a p-side ohmic electrode formed thereon,
The p-type contact layer of the light emitting portion is modified by forming a metal layer made of at least one selected from the group consisting of Ni and Pt and then removing the metal layer. I do.
In the nitride semiconductor light emitting device according to the present invention thus configured, the Ni or Pt layer having a catalytic action releases hydrogen taken in during growth of the nitride semiconductor in the p-type contact layer of the light emitting portion. Is promoted and the resistance value can be lowered.
Therefore, in the nitride semiconductor light emitting device according to the present invention, carriers can be more effectively injected into the active layer located immediately below the light emitting portion, and light emitted from the active layer immediately below the light emitting portion can be emitted. , Can be efficiently emitted from the light emitting portion immediately above.
[0007]
Further, in the nitride semiconductor light emitting device according to the present invention, it is preferable that only the p-type nitride semiconductor layer of the light emitting portion is selectively treated.
[0008]
Also, the nitride semiconductor light emitting device according to the present invention includes a contact layer made of a p-type nitride semiconductor, and a p-side ohmic electrode partially formed on the contact layer except for a light emitting portion. In the light emitting element, at least one metal element selected from the group consisting of Ni and Pt is provided on the surface of the p-type contact layer of the light emitting portion.
[0009]
In the nitride semiconductor light emitting device according to the present invention, the p-side ohmic electrode has an opening, and the light emitting portion can be constituted by the surface of the p-type contact layer exposed by the opening.
Further, it is preferable that the p-side ohmic electrode has a plurality of openings.
Here, the p-side ohmic electrode having an opening is not limited to a specific shape, and may be formed in various shapes such as a comb shape or a mesh shape.
[0010]
In addition, the method for manufacturing a nitride semiconductor light emitting device according to the present invention includes a p-type contact layer made of a p-type nitride semiconductor, and a p-side ohmic portion is formed on the p-type contact layer except for a light emitting portion. In a method for manufacturing a nitride semiconductor light emitting device having electrodes formed thereon,
An electrode forming step of partially forming a p-side ohmic electrode on the p-type contact layer except for a light emitting portion;
Apart from the electrode forming step, a metal layer forming step of forming a metal layer made of a metal selected from the group consisting of Ni and Pt on the surface of the p-type contact layer of the light emitting portion, and a metal for removing the metal layer And a layer removing step.
[0011]
In the method for manufacturing a nitride semiconductor light emitting device according to the present invention, the electrode forming step may be performed before the metal layer forming step so that only the p-type contact layer of the light emitting portion is selectively processed. Including
In the metal layer forming step, it is preferable that the metal layer is formed so as to cover the light emitting portion and the p-side ohmic electrode.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a nitride semiconductor light emitting device according to an embodiment of the present invention will be described with reference to the drawings.
In the nitride semiconductor light emitting device of the present embodiment, an n-side nitride semiconductor layer including an n-type contact layer 3, an active layer 5, and a p-type contact layer 7 are formed on a substrate 1 via a buffer layer 2. A nitride semiconductor light-emitting device having a p-side nitride semiconductor layer provided in the uppermost layer (FIG. 2) and emitting light from the p-type contact layer side, and having the following features.
[0013]
That is, in the nitride semiconductor light emitting device of the embodiment according to the present invention, as shown in FIGS. 1 and 2, the p-side electrode including the p-side ohmic electrode 70 and the p-side pad electrode 71 is formed on the p-type contact layer. By partially forming (having an opening), the surface of the p-type contact layer where the p-side electrode is not formed is used as the light emitting portion 7a.
Then, the p-type contact layer 7 opened as the light emitting portion 7a forms a Ni layer or a Pt layer having a catalytic action to promote the release of hydrogen from the nitride semiconductor, and then forms the Ni layer or the Pt layer. The reforming process is performed through a process of removing by etching.
[0014]
In the nitride semiconductor light emitting device according to the present invention configured as described above, after forming a Ni layer or a Pt layer having a catalytic action, a reforming process of removing the Ni layer or the Pt layer by etching is performed. In the p-type contact layer 7 located at the light emitting portion 7a, the desorption of hydrogen taken in during the growth of the nitride semiconductor is promoted, and the resistance value of the p-type contact layer 7 located under the light emitting portion 7a is increased. Can be lowered.
As a result, carriers can be more effectively injected into the active layer 5 located immediately below the light emitting portion 7a, as compared with a light emitting element that has not been subjected to the modification treatment. Can be efficiently emitted from the light emitting portion 7a immediately above.
[0015]
Further, in the nitride semiconductor light emitting device according to the embodiment configured as described above, after the Ni layer or the Pt layer is formed, the Ni layer or the Pt layer is removed by etching. The Ni element or the platinum element remains on the surface of the p-type contact layer 7 of the emission part 7a and in the vicinity thereof.
As described above, the light emitting device according to the present invention having the Ni element or the platinum element on the surface of the p-type contact layer 7 of the light emitting portion 7a and in the vicinity thereof has a more effective light emitting device than the conventional light emitting device. Carriers can be injected into the active layer 5 located immediately below the portion 7a, and light emitted by the active layer immediately below the light emitting portion 7a can be efficiently emitted from the light emitting portion 7a immediately above.
[0016]
In the above-described nitride semiconductor light emitting device according to the present invention, the above-described modification process is selectively performed on the p-type contact layer 7 located at the light emitting portion 7a (the opening where the p-side electrode is not formed). Is preferred.
With this configuration, the resistance of the p-type contact layer 7 located below the light emitting portion 7a can be made lower than that of the p-type contact layer 7 located below the p-side ohmic electrode. As a result of allowing a large amount of current to flow, carriers can be more effectively injected into the active layer located immediately below the light emitting portion 7a, and light emitted from the active layer immediately below the light emitting portion 7a is The light can be efficiently emitted from the light emitting portion 7a immediately above.
That is, by selectively modifying the p-type contact layer 7 located in the light emitting portion 7a, light emission immediately below the p-side electrode, which makes it difficult to extract emitted light, is suppressed, and light can be easily extracted. It is possible to increase light emission in the active layer located immediately below the light emitting portion 7a.
[0017]
As a specific method of selectively modifying the p-type contact layer 7 located at the light emitting portion 7a, for example, after forming a p-side ohmic electrode having an opening such as a mesh electrode, After forming a Ni layer or a Pt layer so as to be in contact with at least the p-type contact layer exposed at the opening (the simplest method is to cover the entire p-side ohmic electrode), the Ni layer or the Pt layer is then formed. May be removed by etching.
The nitride semiconductor light-emitting device manufactured in this manner has a Ni element or a platinum element together with a Mg element on the surface of the p-type contact layer 7 of the light emitting portion 7a and in the vicinity thereof, and is provided immediately below the p-side ohmic electrode. Although it contains only the Mg element without substantially containing the Ni element or the platinum element, only the p-type contact layer 7 located at the light emitting portion 7a is selectively modified, and the emitted light is Light emission immediately below the p-side electrode, which is difficult to extract, can be suppressed, and light emission in the active layer located immediately below the light emitting portion 7a, from which light can be easily extracted, can be increased.
[0018]
Hereinafter, a method for manufacturing a nitride semiconductor light emitting device according to an embodiment of the present invention will be described.
(Growth process)
In this manufacturing method, first, a buffer layer 2 made of a nitride semiconductor, an n-type contact layer 3, an n-type clad layer 4, an active layer 5, a p-type clad layer 6, and a p-type are formed on a substrate 1 made of, for example, sapphire. By growing the mold contact layer 7, a laminated structure for forming a light emitting portion is produced.
(Formation of n-electrode formation part)
Next, a part of the laminated structure is etched to expose a part of the n-type contact layer 3, as shown in FIG.
[0019]
(P-type annealing)
Further, by performing a heat treatment at 600 ° C., the p-type cladding layer 6 and the p-type contact layer 7 are made p-type.
(Formation of p-side ohmic electrode)
Next, after forming Rh (400 °), Ir (500 °), and Pt (1000 °) in this order on the p-type contact layer 7, the p-side ohmic electrode 70 is partially (mesh-shaped) by patterning. .
The p-side ohmic electrode 70 is preferably formed in a pattern such as a mesh shape, a stripe shape, or the like, in which an opening portion where the p-side ohmic electrode is not formed can be relatively large. Patterning can be performed by various methods such as a method of etching using a method and a lift-off method.
The p-side ohmic electrode is formed by using a material that can obtain a preferable ohmic characteristic with a p-type contact layer. Examples of the material that can obtain a preferable ohmic characteristic with the p-type contact layer include Rh, Ir, Pt, Ru, W, and W. Ti and the like.
[0020]
(Formation of p-side pad electrode)
Next, the p-side pad electrode 71 is formed as shown in FIG. The p-side pad electrode has a two-layer structure in which, for example, Pt is formed to a thickness of 400 ° and Au is formed to a thickness of 6500 °.
(P ohmic annealing)
Next, heat treatment (annealing) is performed at 600 ° C. in order to obtain good ohmic contact between the p-type contact layer 7 and the p-side ohmic electrode 70.
[0021]
(N-electrode formation)
Next, for example, the n-electrode 30 formed by laminating W (200 °), Al (2000 °), W (500 °), Pt (1000 °), and Au (3500 °) is exposed by etching a part of the laminated structure. The n-type contact layer 3 is formed on the surface (n-electrode formation portion).
When a material that is hardly oxidized is used for the n-electrode, the n-electrode may be formed before the p-ohmic annealing step.
(Formation of Ni layer)
Next, a Ni layer having a thickness of, for example, 60 ° is formed so as to cover the entire surface of the p-type contact layer 7.
(Removal of Ni layer)
Then, the Ni layer is removed by wet etching.
It is preferable to select an etchant that dissolves only Ni and does not dissolve the p-side ohmic electrode and the p-side pad electrode.
In addition, in the present invention, the Ni layer may be removed after forming at least the opening on the p-type contact layer 7 where the p-side ohmic electrode is not formed.
[0022]
As described above, the method for manufacturing the nitride semiconductor light emitting device of the present embodiment includes the reforming step including the Ni forming step and the step of removing the Ni. The desorption of hydrogen taken in during the growth of the target semiconductor is promoted, and the resistance value of the p-type contact layer located below the light emitting portion 7a can be reduced.
[0023]
Further, in the method for manufacturing a nitride semiconductor light emitting device of the present embodiment, since the p-side electrode is formed in a predetermined pattern and then the modification process is performed, the light emitting portion 7a (the p-side electrode is formed). The opening can be selectively applied to the p-type contact layer 7 located at the opening (not provided).
Therefore, according to the manufacturing method of the present embodiment, carriers can be more effectively injected into the active layer 5 located immediately below the light emitting portion 7a, and the active layer immediately below the light emitting portion 7a emits light. It is possible to manufacture a nitride semiconductor light emitting device that can efficiently emit the emitted light from the light emitting portion 7a immediately above.
Further, as in the present embodiment, the nitride semiconductor device in which the light emitting portion is subjected to the modification process and the p-side ohmic electrode formation portion is not subjected to the modification process is provided on the p-type contact layer. Ni is deposited only on the emission part. At this time, Ni is formed by sputtering or the like, so that the film thickness is increased from the central portion of the light emitting portion to the boundary surface with the p-side ohmic electrode. Therefore, in the reforming process in the present embodiment, the desorption of hydrogen is more promoted in the portion closer to the boundary surface than in the center of the opening (that is, the reforming process is performed more strongly), and the resistance value is also increased. Lower. Thereby, in the light emitting portion, particularly strong light is emitted from the vicinity of the boundary with the p-side ohmic electrode.
Therefore, for example, in the case of a p-side ohmic electrode having a plurality of openings constituting a light emitting portion, such as a mesh-shaped p-side ohmic electrode, the vicinity of a boundary where a low resistance value and strong light are emitted (the portion where the strong light is emitted) The size of the opening (for example, mesh) is set so that the ratio of the area of the opening to the entire opening is large even if the area of the opening is changed.
[0024]
In the manufacturing method according to the above-described embodiment, after the p-side electrode (both the p-side ohmic electrode and the p-side pad electrode) is formed in a predetermined pattern, the modification process is performed.
However, in the present invention, after the p-side ohmic electrode 70 is formed in a predetermined pattern, a reforming process may be performed before the formation of the p-side pad electrode 71.
Even in the case described above, it can be selectively performed on the p-type contact layer 7 located at the light emitting portion 7a, and has the same operation and effect as the manufacturing method of the embodiment.
[0025]
Further, in the present invention, before forming the p-side ohmic electrode 70, after performing a reforming process of forming a Ni layer on the entire surface of the p-type contact layer 7 and removing the Ni layer, the p-side ohmic electrode 70 is formed. And the p-side pad electrode 71 may be formed in a predetermined pattern.
Even in the case described above, carriers can be more effectively injected into the active layer located immediately below the light emitting portion 7a as compared with a conventional light emitting element that has not been modified. The light emitted from the active layer immediately below the emission section 7a can be efficiently emitted from the light emission section 7a immediately above.
As described above, when the surface is modified over the entire surface before the p-side electrode is formed, the carrier injection efficiency is increased even immediately below the p-side ohmic electrode. (It is still the case that the light can be emitted more efficiently than the conventional light emitting device), but the mesh electrode is formed on the p-type contact layer slightly roughened by the surface modification. There is an advantage that the mesh electrode can be formed with good adhesion.
[0026]
【Example】
Hereinafter, examples according to the present invention will be described.
Embodiment 1 FIG.
Example 1 will be described with reference to FIG.
Although not shown in FIG. 1 in the first embodiment, the buffer layer 2 includes an undoped GaN layer, and the p-type cladding layer 6 includes a lightly doped p-type lightly doped layer. In place of the n-type clad layer 1, a first multilayer film layer and an n-type superlattice multilayer film layer are included.
[0027]
(Substrate 1)
The substrate 1 made of sapphire (C surface) is set in a MOVPE reaction vessel, and while flowing hydrogen, the temperature of the substrate is raised to 1050 ° C. to clean the substrate.
[0028]
(Buffer layer 2)
Subsequently, the temperature is lowered to 510 ° C., and a buffer layer 2 made of AlGaN is grown on the substrate 1 to a thickness of about 200 angstroms using hydrogen as a carrier gas and ammonia and TMG (trimethylgallium) as a source gas. Note that the first buffer layer 2 grown at a low temperature can be omitted depending on the type of the substrate, the growth method, and the like.
[0029]
(Undoped GaN layer)
After the growth of the buffer layer 2, only TMG is stopped, and the temperature is increased to 1050 ° C. When the temperature reaches 1050 ° C., an undoped GaN layer is grown to a thickness of 1.5 μm using TMG and ammonia gas as the source gas.
[0030]
(N-side contact layer 3)
Subsequently, at 1050 ° C., TMG, ammonia gas and silane gas were used as the source gas and the ¹⁸ / Cm ³ An n-side contact layer 3 made of doped GaN is grown to a thickness of 1.85 μm.
[0031]
(First multilayer film layer)
Next, only the silane gas was stopped, and a lower layer of undoped GaN was grown to a thickness of 3000 Å at 1050 ° C. using TMG and ammonia gas. Subsequently, silane gas was added at the same temperature to add 6 × 10 ¹⁸ / Cm ³ An intermediate layer made of doped GaN is grown to a thickness of 300 angstroms, then only silane gas is stopped, and an upper layer made of undoped GaN is grown at the same temperature to a thickness of 50 angstroms to form a total film consisting of three layers. A first multilayer layer having a thickness of 3350 Å is grown.
[0032]
(N-type superlattice multilayer film layer)
Next, at a similar temperature, a first nitride semiconductor layer made of undoped GaN is grown at 40 Å, then the temperature is set to 800 ° C., and undoped In is formed using TMG, TMI and ammonia. _0.02 Ga _0.98 A second nitride semiconductor layer made of N is grown by 20 angstroms. These operations are repeated so that ten layers are alternately stacked in a first + second order, and finally, a first nitride semiconductor layer made of GaN is grown by 40 angstroms to form an n-type superlattice multilayer film. A superlattice multilayer is grown to a thickness of 640 angstroms.
[0033]
(Active layer 5)
Next, a barrier layer made of undoped GaN is grown to a thickness of 200 angstroms, then the temperature is raised to 800 ° C., and undoped In _0.4 Ga _0.6 A well layer made of N is grown to a thickness of 30 Å. Then, five barrier layers and four well layers are alternately stacked in the order of barrier + well + barrier + well... Let it.
[0034]
(Medium concentration doped multilayer p-type cladding layer 6)
Next, at a temperature of 1050 ° C., TMG, TMA, ammonia, Cp ₂ Using Mg (cyclopentadienyl magnesium), ¹⁹ / Cm ³ Doped p-type Al _0.2 Ga _0.8 A first nitride semiconductor layer made of N is grown to a thickness of 40 angstroms, then the temperature is set to 800 ° C., and TMG, TMI, ammonia, Cp ₂ 5 × 10 Mg using Mg ¹⁹ / Cm ³ Doped In _0.03 Ga _0.97 A second nitride semiconductor layer made of N is grown to a thickness of 25 Å. Then, these operations are repeated, and five layers are alternately laminated in the order of first + second, and finally, the first nitride semiconductor layer is formed of a multilayer film having a superlattice structure in which the first nitride semiconductor layer is grown to a thickness of 40 Å. The side multilayer clad layer 6 is grown to a thickness of 365 angstroms.
[0035]
(Lightly doped p-type lightly doped layer)
Subsequently, a p-type lightly doped layer of undoped GaN is grown to a thickness of 2000 Å at 1050 ° C. using TMG and ammonia. This low-concentration doped layer is grown as undoped during growth, but Mg doped in the medium-concentration doped multilayer p-type cladding layer 6 diffuses during the growth of the low-concentration doped layer 9, and When the highly doped p-type contact layer 7 is grown, Mg diffuses, and the lightly doped layer shows p-type.
The Mg concentration of this lightly doped layer is 2 × 10 ¹⁸ / Cm ³ It becomes. Further, as shown in FIG. 2, the change in the Mg concentration of the low-concentration doped layer shows almost the same value as the Mg concentration of the p-type cladding layer 6 at the portion in contact with the p-type cladding layer 6. The Mg concentration gradually decreases as the distance from the layer 6 increases, and the Mg concentration in the vicinity of the p-type contact layer 7 to be grown later (immediately before the growth of the p-type contact layer 7) shows almost the lowest value.
[0036]
(Highly doped p-type contact layer 7)
Subsequently, at 1050 ° C., TMG, ammonia, Cp ₂ Using Mg, Mg is 1 × 10 ²⁰ / Cm ³ A p-type contact layer 7 made of doped GaN is grown to a thickness of 1200 Å.
After completion of the reaction, the temperature is lowered to room temperature, and the wafer is annealed in a reaction vessel at 700 ° C. in a nitrogen atmosphere to further reduce the resistance of the p-type layer.
[0037]
After annealing, the wafer is taken out of the reaction vessel, a mask having a predetermined shape is formed on the surface of the uppermost p-type contact layer 7, and etching is performed from the p-type contact layer 7 side by an RIE (reactive ion etching) apparatus. As shown in FIG. 1, the surface of the n-type contact layer 3 is exposed.
[0038]
Next, on the p-type contact layer 7, Rh is formed at 400 °, Ir at 500 °, and Pt at 1000 ° in this order.
Next, at the position where the p-side pad electrode faces the n-type contact layer 3, Pt is formed in the order of 400 ° and Au is formed in the order of 6500 °.
After the p-side pad electrode 71 is formed, the exposed p-side ohmic electrode is patterned to form the p-side ohmic electrode 70 in a mesh shape. The lift-off method is used for the formation method.
[0039]
Next, heat treatment (annealing) is performed at 600 ° C. in order to obtain good ohmic contact between the p-type contact layer 7 and the p-side ohmic electrode 70.
Next, an n-electrode 30 is formed on the exposed surface of the n-type contact layer 3 by laminating W at 200 °, Al at 2000 °, W at 500 °, Pt at 1000 °, and Au at 3500 ° in this order.
Next, a Ni layer having a thickness of 60 ° is formed so as to cover the entire surface of the p-type contact layer 7. Further, the Ni layer is removed by wet etching using diluted nitric acid or concentrated hydrochloric acid.
[0040]
Thus, a nitride semiconductor device is obtained. In this nitride semiconductor device, on the surface of the p-type contact layer 7 serving as a light extraction surface, the p-side ohmic electrode 70 is formed in a mesh shape except for the p-side pad electrode formation portion, and the mesh formation portion is separated from the p-side pad electrode 71. It is formed.
In the nitride semiconductor light emitting device of Example 1 configured as described above, the forward voltage Vf when the forward current was 20 mA was 3.61 V.
[0041]
Embodiment 2. FIG.
The nitride semiconductor light emitting device according to the second embodiment is different from the first embodiment in that the entire p-type contact layer is modified before the p-side ohmic electrode is formed, and thereafter, the p-side ohmic electrode and the p-side pad electrode are formed. In contrast to Example 1, other points were made in the same manner as in Example 1.
As a result, in the nitride semiconductor light emitting device of Example 2, the forward voltage Vf was 3.64 V when the forward current was 20 mA.
[0042]
Comparative Example 1
The nitride semiconductor light emitting device of Comparative Example 1 was manufactured in the same manner as in Example 1 except that the modification treatment was not performed.
As a result, in the nitride semiconductor light emitting device of Comparative Example 1, the forward voltage Vf was 3.67 V when the forward current was 20 mA.
[0043]
Modified example
In the present embodiment and examples, the p-side ohmic electrode is not meshed below the p-side pad electrode 71. However, in the present invention, the p-side ohmic electrode below the p-side pad electrode 71 may have a mesh shape. Further, the steps of forming and removing Ni for surface modification may be performed before forming the p-side pad electrode or after forming the p-side pad electrode.
By doing so, the forward voltage Vf can be further reduced.
In this case, the output may decrease due to the light emitted from the opening of the p-side ohmic electrode being absorbed by the p-side pad electrode, but the p-side ohmic electrode of the p-side pad electrode and the p-type contact may be reduced. By forming the Rh layer as a layer in contact with the layer, light absorption by the p-side pad electrode can be suppressed, and a decrease in output can be prevented.
[0044]
【The invention's effect】
As is apparent from the above description, in the nitride semiconductor light emitting device according to the present invention, the p-type nitride semiconductor layer of the light emitting portion is formed of at least one selected from the group consisting of Ni and Pt. Since the metal layer is formed and then modified by removing the metal layer, the metal layer is removed during the growth of the nitride semiconductor in the p-type contact layer of the light emitting portion by the catalytic action of the Ni layer or the Pt layer. Separation of hydrogen is promoted, and the resistance value can be reduced.
Therefore, according to the nitride semiconductor light emitting device of the present invention, carriers can be more effectively injected into the active layer located immediately below the light emitting portion, and light is emitted from the active layer immediately below the light emitting portion. Light can be efficiently emitted from the light emitting portion immediately above, and a nitride semiconductor light emitting device having high luminous efficiency and high light extraction efficiency can be provided.
[Brief description of the drawings]
FIG. 1 is a plan view of a nitride semiconductor light emitting device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA ′ of FIG.
3 is a partially enlarged sectional view showing a part of the sectional view of FIG. 2 in an enlarged manner.
FIG. 4 is a partially enlarged cross-sectional view showing a part of a cross section of a nitride semiconductor light-emitting device of a modified example according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... board | substrate, 2 ... buffer layer, 3 ... n-type contact layer, 4 ... n-type cladding layer, 5 ... active layer, 6 ... p-type cladding layer, 7 ... p-type contact layer, 7a ... light emission part, 70 ... p-side ohmic electrode, 71 ... p-side pad electrode.

Claims (9)

A nitride semiconductor light-emitting device comprising a p-type contact layer made of a p-type nitride semiconductor, and a p-side ohmic electrode partially formed on the p-type contact layer except for a light emitting portion,
The p-type contact layer of the light emitting portion is modified by forming a metal layer made of at least one selected from the group consisting of Ni and Pt and then removing the metal layer. Nitride semiconductor light emitting device. 2. The nitride semiconductor light emitting device according to claim 1, wherein said metal layer is a Ni layer. 3. The nitride semiconductor light emitting device according to claim 1, wherein only the p-type nitride semiconductor layer of the light emitting portion is modified. A nitride semiconductor light-emitting device comprising a p-type contact layer made of a p-type nitride semiconductor, and a p-side ohmic electrode partially formed on the p-type contact layer except for a light emitting portion,
A nitride semiconductor light emitting device comprising at least one metal element selected from the group consisting of Ni and Pt on a surface of a p-type contact layer of the light emitting portion. 5. The nitride semiconductor light emitting device according to claim 4, wherein said metal element is Ni. The said p-side ohmic electrode has an opening part, The said light emission part was comprised by the said p-type contact layer surface exposed by the opening part, The any one of Claims 1-5. Nitride semiconductor light emitting device. 7. The nitride semiconductor light emitting device according to claim 6, wherein said p-side ohmic electrode has a plurality of said openings. A method for manufacturing a nitride semiconductor light-emitting device, comprising: a contact layer made of a p-type nitride semiconductor; and a p-side ohmic electrode partially formed on the contact layer except for a light emitting portion.
An electrode forming step of partially forming a p-side ohmic electrode on the p-type contact layer except for a light emitting portion;
Apart from the electrode forming step, a metal layer forming step of forming a metal layer made of a metal selected from the group consisting of Ni and Pt on the surface of the p-type contact layer of the light emitting portion, and a metal for removing the metal layer A method for manufacturing a nitride semiconductor light emitting device, comprising a layer removing step. Before the metal layer forming step, including the electrode forming step,
9. The electrode forming method according to claim 8, wherein, in the metal layer forming step, the metal layer is formed so as to cover the light emitting portion and the p-side ohmic electrode.

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