JP2002313749A - LIGHT-EMITTING DEVICE n TYPE ELECTRODE, ITS MANUFACTURING METHOD AND III GROUP NITRIDE SEMICONDUCTOR LIGHT-EMITTING DEVICE USING THE SAME - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a III group nitride semiconductor light-emitting device n-type electrode which is low in contact resistance and is superior in bondability, and a III group nitride semiconductor light-emitting device utilizing the same. SOLUTION: A nickel thin film is formed on the surface of an n-type III group nitride semiconductor, and an n-type electrode of a 2-layer structure in which an aluminum thin film is further mounted to a surface of the nickel thin film is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device using a group III nitride semiconductor used as a blue light emitting device, such as a light emitting device or a laser device, and more particularly to an ohmic device provided on the surface of an n-type group III nitride semiconductor. The present invention relates to a contacting electrode structure and a group III nitride semiconductor light emitting device using the n-type electrode.

[0002]

2. Description of the Related Art In recent years, as a light-emitting element that emits light in a blue band or a green band, In _x Al _Y Ga _{1 -XYN} (0 ≦ X <
Group III nitride semiconductor light-emitting devices represented by 1, 0 ≦ Y <1) have attracted attention. The group III nitride semiconductor light emitting device is, for example, as shown in the sectional structure of FIG. 3, on a substrate 31 made of sapphire (α-Al ₂ O ₃ ) single crystal, a metal organic chemical vapor deposition (MOCVD) method. And the like. It is composed of an epitaxially grown layer of a group III nitride semiconductor deposited by using such a growth means. In the laminated structure shown in FIG. 3, first, a buffer layer 32 made of GaN is formed on a substrate 31, and an n-type contact layer 33 made of silicon-doped n-type GaN is formed on the buffer layer 32. A light emitting layer 34 made of non-doped In _0.2 Ga _0.8 N thereon;
Magnesium-doped p-type Al _0.1 G on the light emitting layer 34
A p-type upper cladding layer 35 of a _0.9 N and a p-type contact layer 36 of magnesium-doped p-type GaN are sequentially epitaxially grown on the upper cladding layer 35 to form a laminate.

In the light emitting device having the above structure, the α-Al ₂ O ₃ single crystal used as the substrate has an insulating property.
An electrode for supplying a current to the light emitting element is located on the same side of the substrate as p.
The structure is such that both poles and n-pole electrodes are formed.
In the example of the light emitting element shown in FIG.
The p-type contact layer 36 is made of aN. Therefore, on the surface of the p-type contact layer 36, a translucent electrode having low contact resistance and transparent to light emission must be provided over a wide range as much as possible. On the other hand, the counter electrode n
Since the substrate is insulative, the n-type contact layer 3 made of GaN is formed by exposing a part of the stacked body composed of the epitaxially grown layer by etching to expose the n-type electrode.
3 is formed. The n-type electrode must also be in ohmic contact with the n-type contact layer 33 and have a low contact resistance. In the example of the light emitting element shown in FIG.
An n-type electrode 40 made of an aluminum film is formed on the surface of the mold contact layer 33. In many cases, the ball-shaped gold 21 is welded to the p-type electrode pad 39 and the n-type electrode 40 using a wire bonder. The bonding wire 22 is connected.

Conventionally, as an n-type electrode formed on the surface of an n-type contact layer, an alloy containing chromium and / or nickel (see JP-A-6-257868), titanium (Ti), aluminum (Al) or An electrode using a titanium-aluminum alloy (see JP-A-6-257868) is known. Electrodes made of these metals are said to form a good ohmic junction with an n-type group III nitride semiconductor.

On the other hand, a p-type group III nitride semiconductor contact
The light-transmitting electrode formed on the layer has a thickness of 0.01 to
0.2 μm chromium (Cr), nickel (Ni), gold
Gold such as (Au), titanium (Ti) or platinum (Pt)
Metallic thin films have been used (Japanese Patent Laid-Open No. 6-314822).
reference). These metal thin films are formed by means such as vacuum evaporation.
After being formed, by annealing in an appropriate temperature range,
Ohmic contact is obtained by diffusing over the entire contact layer
It has been. In addition, thin films of these metals are
It is known that it shows a transmittance of 40 to 60% for visible light.
Have been. Also, nickel (Ni) as a translucent electrode,
Platinum (Pt), palladium (Pd), rhodium (R
h), ruthenium (Ru), osmium (Os) or
Represents a first layer made of a metal thin film such as iridium (Ir);
Zinc (Zn), Indium (In), Tin (Sn), Mag
Oxides such as nesium (Mg), specifically ZnO, In
_TwoO_Three, SnO_Two Of tin, MgO or indium and tin
Conductive thin metal oxide such as Indium Tin Oxide (ITO)
It is known that the second layer composed of a film has a two-layer structure.
(See Japanese Patent Application Laid-Open No. 9-129919). Metal acid
Transparent electrode with two-layer structure using oxide conductive thin film
High ohmic characteristics and high brightness with high external quantum efficiency
It is said that an optical element can be obtained.

[0006]

However, an n-type electrode made of aluminum (Al) or a titanium-aluminum alloy formed on the surface of an n-type contact layer, which has been conventionally used, has poor bondability and is not suitable for light emitting diodes. In the process of forming the semiconductor device, there is a problem that the n-type contact layer and the n-type electrode metal are separated and the product yield is reduced. The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has good bondability, does not cause separation from an n-type contact layer, and furthermore, a group III nitride that forms a good ohmic contact with the n-type contact layer. An object of the present invention is to provide an n-type electrode for a semiconductor and a group III nitride semiconductor light emitting device using the same.

[0007]

That is, an n-type electrode for a group III nitride semiconductor according to the present invention is a light emitting device in which a nickel (Ni) thin film and an aluminum (Al) thin film are sequentially laminated on an n-type group III nitride semiconductor surface. The device was an n-type electrode. N-type electrode is N
By having a two-layer structure of i and Al, there is no separation from the n-type contact layer, and n is excellent in bondability to form a good ohmic contact with the n-type contact layer.
It can be a shaped electrode.

[0008] The n-type electrode of the present invention is also effective when the n-type group III nitride semiconductor is n-type GaN. G
Since aN is easily lattice-matched with another group III nitride semiconductor to obtain a high-quality crystal, and it is easy to obtain an n-type semiconductor layer by selecting a dopant, an n-type contact in a group III nitride semiconductor light emitting device is obtained. Useful as a layer.

In the n-type electrode according to the present invention, the Ni thin film has a thickness of 0.05 to 1 μm, and the Al thin film has a thickness of 0.4 to 1 μm.
It is preferably 2 μm. More preferably, the thickness of the Ni thin film is 0.1 to 0.5 μm. The thickness of the Al thin film is 0.5 to 1 μm. This is for reducing the contact resistance with the n-type contact layer and obtaining a strong bond with the n-type contact layer and the bonding wire.

The method for manufacturing an n-type electrode for a light-emitting device according to the present invention is characterized in that the thickness of the n-type electrode is 0.05 to
Nickel (Ni) thin film of 1 μm and thickness of 0.4 to 2 μm
After sequentially laminating aluminum (Al) thin films of
Annealing was performed at a temperature of ６００600 ° C. . By adopting such a method, bondability is good,
It is possible to easily form an n-type electrode for a group III nitride semiconductor that does not peel off from the n-type contact layer and forms a good ohmic contact with the n-type contact layer.

The group III nitride semiconductor light emitting device of the present invention comprises:
What is claimed is: 1. A light emitting device comprising a light emitting layer comprising a group III nitride semiconductor on a substrate, wherein the group III nitride comprises an n-type group III nitride semiconductor surface provided with the aforementioned n-type electrode for a light emitting device according to the present invention. A semiconductor light emitting device was used. The group III nitride semiconductor light emitting device of the present invention has good bondability of an n-type electrode,
Since there is no delamination with the n-type contact layer and good ohmic contact with the n-type contact layer, a high-performance and high-luminance Group III nitride semiconductor light-emitting device can be obtained with a high product yield. In the group III nitride semiconductor light emitting device of the present invention, particularly, the light emitting layer is made of InGaN or InGa.
It is preferable to have a multiple quantum well (MQW) structure composed of N and GaN.

In general, a group III nitride semiconductor has a high band gap energy and can emit light of a short wavelength, and is extremely useful not only for a display device but also for a laser device capable of coping with a high recording density of an optical disk. is there. Further, if the light emitting portion has an MQW structure, the injected electron-hole pairs form a two-dimensional exciton, and the binding energy and the oscillator strength are larger than those of the bulk crystal, and are stable even at room temperature. As a result, a high power laser diode with low power consumption can be obtained. If this is used, stable oscillation of laser light can be achieved. Short wavelength lasers are especially important for information storage technology because they can increase optical recording density.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Group III nitride semiconductor light emission of the present invention
The light emitting part structure of the element is sapphire (α-Al _TwoO_Three)
It is formed on the surface of a substrate made of a crystalline material. On the surface of the board
Form a buffer layer. The buffer layer is the substrate and the group III nitride semiconductor
To mitigate the effects of lattice mismatch with
Thus, for example, it is formed of GaN or the like from which good quality crystals can be easily obtained.
You. The layer thickness is 0.01 to 0.02 μm. The buffer layer is
In addition to the MOCVD method, it can be formed by a vapor phase growth method or the like.
it can. In addition, a mirror-like GaN-based
As a method of creating a semiconductor crystal, a method other than the buffer layer is used.
May be used. For example, called the Seeding Process method
Forming a metal droplet on a high-temperature sapphire substrate
A method using a nitrided crystal mass as a crystal growth nucleus, HVPE
(Hydrogen vapor phase epitaxy)
I do not care. Mirror-like tables created using these methods
On a GaN-based compound semiconductor crystal having a plane, for example,
An n-type contact layer is formed. For example, n-type contact layer
Using n-type dopants such as silicon,
Form. The light emitting structure is provided on the n-type contact layer.
In addition, an n-type electrode is formed by removing a part as described later.
Therefore, the thickness is generally about 1 μm or more.
You. For example, an n-type contact layer is formed on the surface of the buffer layer.
I do.

A light emitting structure is provided on the n-type contact layer. This light emitting structure has a structure of In _X Al _Y Ga _{1 -XYN} (0 ≦ X
A group III nitride semiconductor represented by <1, 0 ≦ Y <1) is used as a light emitting layer. The light emitting layer is, for example, Ga
N, In _X Ga _1-X N (0 <X <1), Al _Y Ga _1-Y N
(0 <Y <1), In _X Al _Y Ga _{1 -XYN} (0 <X <
1, 0 <Y <1) and the like can be used. These group III nitride semiconductors have band gap energies of about 2 to 6 eV and can emit laser light of blue-violet and ultraviolet light having a wavelength shorter than 430 nm from green visible light and blue visible light having a wavelength of about 530 nm. Becomes The light emitting structure of the present invention is configured by joining the above light emitting layers with cladding layers of different conductivity types. Usually, a material having a higher band gap energy than that of the light emitting layer is used for the cladding layer, electrons are injected into the light emitting layer,
-Configured to promote n-bonding. The junction types include a homojunction in which the same crystals of different conductivity types are joined, a single hetero (SH) junction in which different conductivity types of different crystals are joined, and a double hetero (DH) in which the light emitting layer is sandwiched between two types of different crystals. Joining etc. can be used.

For the purpose of low power consumption and large output, a quantum well (Multiple Quantum Well: MQW) structure in which two compound semiconductor thin films are alternately stacked on a light emitting layer can be adopted. With the MQW structure, the injected electron-hole pairs form a two-dimensional exciton, and the binding energy and the oscillator strength are larger than those of the bulk crystal, so that they exist stably even at room temperature. . If this is used, stable oscillation of laser light can be achieved. Short wavelength lasers are especially important for information storage technology because they can increase optical recording density. The MQW structure also has a structure in which the light emitting layer is sandwiched between cladding layers having different conduction types and a large band gap energy.

The light emitting layer contains In _x containing indium (In).
When a crystal represented by Al _Y Ga _{1 -XYN} (0 <X <1, 0 ≦ Y <1) is used, in order to prevent volatilization of the In element in a later step, AlGaN or GaN is used. It is preferable to provide a thin film as a diffusion prevention layer. A contact layer is formed on the light emitting structure. The contact layer has a conductivity type opposite to that of the contact layer formed prior to the formation of the light emitting structure. Normally, the contact layer on the substrate side is n-type, and the contact layer on the opposite side of the light-emitting layer from the substrate is p-type. The light extraction direction is on the p-type contact layer side. Further, InGaN may be formed as a contact layer on the outermost surface on the p-side. InGaN is GaN
Since the band gap is small as compared with the above, there are advantages such as easy formation of ohmic negotiation with a metal and a high activation rate of p carriers. The contact layer uniformly supplies an operating current to the entire surface of the light emitting element.
Each p-type contact layer must be lattice-matched with the group III nitride semiconductor to be joined and have a low specific resistance.
In addition, on each of the n-type and p-type contact layers, a good ohmic junction for connecting to an external power supply is formed.
And a p-type electrode.

A translucent p-type electrode is formed on the p-type contact layer in the light extraction direction. In the present invention, a gold (Au) thin film and silicon dioxide (SiO) are used as p-type electrodes.
₂ ) A translucent electrode having a two-layer structure in which thin films are sequentially laminated is employed. The thickness of the gold thin film is suitably from 0.003 to 1 μm, more preferably from 0.005 to 0.1 μm. In general, it is known that even a metal is light-transmitting if it is a thin film. However, in order to obtain high light transmittance, the thickness of the gold thin film needs to be within the above range. Since gold has a low specific resistance, an operating current can be diffused over the entire surface of the p-type contact layer by using a thin film having the above thickness, and uniform light emission can be extracted from the entire surface of the element. A silicon dioxide thin film having a thickness of 0.
Deposit 5 to 3 μm, more preferably 0.5 to 1.5 μm. This is because the silicon dioxide thin film serves as a protective film that prevents the gold thin film from ball-up and breaking the gold thin film when annealing is performed to obtain ohmic contact between the p and n electrodes in a later step. . In order to suppress ball-up of the gold thin film and maintain high translucency, the thickness of the silicon dioxide thin film needs to be in the above range.

On the other hand, an n-type electrode serving as a counter electrode is formed on the n-type contact layer. For this reason, a part of the once-grown epitaxial growth layer is removed by etching to expose the n-type contact layer, and n is formed on the exposed n-type contact layer.
Form a mold electrode. n-type I to form n-type contact layer
Aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), or an alloy thereof can be used as an electrode material that forms an ohmic junction with the group II nitride semiconductor. These metal materials are vacuum-deposited on the n-type contact layer to form a thin film of 0.4 to 3 μm,
Annealing is performed at a temperature of 0 ° C. to form an n-type electrode that makes ohmic contact. At this time, first, the film thickness is 0.05 to 1 μm.
It is preferable to form an Al film having a thickness of about 0.4 to 2 μm after forming a Ni thin film having a thickness of about 2 to form a two-layer structure.
This is because such a structure does not cause separation from the n-type contact layer, and can provide an n-type electrode having excellent bondability and good ohmic contact with the n-type contact layer.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a group III nitride semiconductor light emitting device according to the present invention will be described in detail based on embodiments. (Embodiment) FIG. 1 shows an M-type semiconductor having a gallium nitride phosphide crystal layer.
Gallium nitride (GaN) having a light emitting part structure of QW structure
It is a plane schematic diagram of a system LED. FIG. 2 is a diagram showing a stacked structure of the gallium nitride (GaN) -based blue LED shown in FIG. 1, and is a cross-sectional view taken along line AA ′ of FIG.

The light emitting device of this embodiment was manufactured by the following method. Sapphire (α-Al ₂ O ₃ ) as the substrate 1
It was used. A buffer layer 2 made of non-doped GaN, a low n-doped GaN layer 3, an n-type contact layer 4 made of n-type GaN, n-type In
A lower cladding layer 5 composed of GaN, a light emitting layer 6 having an MQW structure composed of a well layer composed of InGaN and a GaN barrier layer,
Anti-diffusion layer 7 made of non-doped AlGaN, p-type G
An epitaxial wafer was formed by sequentially laminating a p-type layer 8 made of aN and a p-type contact layer 9 made of p-type InGaN. , GaN buffer layer 2 and low n-doped GaN layer 3 are grown using trimethylgallium ((CH
_{3) 3} Ga) / gas mixture of ammonia (NH ₃₎ was used as the raw material gas. N-type contact layer 4 made of GaN
For the growth of, a mixed gas of trimethylgallium ((CH ₃ ) ₃ Ga) / ammonia (NH ₃ ) is used as a source gas, and disilane (Si ₂ H ₆ ) is used as a dopant.
/ Hydrogen (H ₂ ) mixed gas was used. In growing the lower cladding layer 5 made of n-type InGaN, a mixed gas of trimethylgallium ((CH ₃ ) ₃ Ga) / trimethyl indium ((CH ₃ ) ₃ In) / ammonia (NH ₃ ) is used as a source gas. The dopant is disilane (Si
₂ H ₆₎ was used / hydrogen (H ₂₎ mixed gas.

For the growth of the light emitting layer 6 having the MQW structure composed of the well layer composed of InGaN and the GaN barrier layer, trimethyl gallium ((CH ₃ ) ₃ Ga) / trimethyl indium ((CH ₃ ) ₃ In) / ammonia (NH) The mixed gas of ₃ ) was used. The growth of the diffusion preventing layer 7 made of non-doped AlGaN is performed using trimethylgallium ((CH ₃ ) ₃ G).
A mixed gas of a) / trimethylaluminum ((CH ₃ ) ₃ Al) / ammonia (NH ₃ ) was used. p-type GaN
The growth of the p-type layer 8 made of trimethylgallium ((CH ₃ ) ₃ Ga) / ammonia (N
Using a mixed gas of H _3), as a dopant, biscyclopentadienyl magnesium _{((C 5 H 5) 2} M
g) was used. To grow the p-type contact layer 9 made of p-type InGaN, trimethyl gallium ((CH ₃ ) ₃ Ga) / trimethyl indium ((C
A mixed gas of H ₃ ) ₃ In) / ammonia (NH ₃ ) was used, and biscyclopentadienyl magnesium ((C ₅ H ₅ ) ₂ Mg) was used as a dopant.

A gold (Au) thin film 10 and a silicon dioxide thin film 11 were formed on the surface of the p-type contact layer 9 made of InGaN of the epitaxial wafer formed as described above. One corner of the silicon dioxide thin film 11 is removed by etching, and a three-layer consisting of a titanium (Ti) thin film 12, an aluminum (Al) thin film 13, and a gold (Au) thin film 14 is formed as a bonding pad 18 at one corner of the gold (Au) thin film 10. Deposited films were sequentially formed. The formation of the translucent electrode 17 and the bonding pad 18 was performed as follows.

A gold piece was placed on a boat serving as an evaporation source using a resistance heating type vacuum evaporation apparatus. The above-described epitaxial wafer was loaded into this vacuum deposition apparatus, and the pressure in the apparatus was reduced to 3.99 × 10 ⁻⁴ Pa. Next, the heater of the evaporation source is energized and heated, and the shutter is opened to start the deposition of the gold film. When the film thickness of the gold vapor deposition reaches 10 nm while monitoring the film pressure with a quartz-crystal vibrating film pressure type, the shutter is closed. Thus, the formation of the gold thin film 10 was completed.

Next, the gel is applied using a spin coating method.
Silicon dioxide (SiO_Two ) In organic solvent
Is applied on the gold vapor-deposited film and heat-treated in an inert atmosphere.
And heat-treated in an argon atmosphere containing 10% oxygen.
1.7 μm thick SiO _Two Silicon dioxide thin film consisting of
11 was formed. In addition, general photolithography
Using the SiO2 technology_Two Silicon dioxide thin
By patterning the film 11, the film 11 is formed on the epitaxial wafer.
The silicon dioxide thin film 11 is located at a position to be a corner of the rectangular element of FIG.
Opening was provided. Furthermore, for wire bonding
As a pad, the entire surface of this epitaxial wafer
In addition, titanium (Ti), aluminum (Al) and gold (A
u) were sequentially formed in three layers. Of each deposited film
The thicknesses are as follows: Ti: 0.1 μm, Al: 0.5 μm, Au:
It was 0.5 μm. In addition, normal photolithography
Patterning the three layers of deposited film using
And the position of the opening of the silicon dioxide thin film 11 to be the corner of the element.
Leaving only three layers, removing the other parts of the deposited film
Thus, a bonding pad 18 for a p-electrode was formed. Most
Later, a p-type contact layer 9 made of GaN and a translucent electrode
10% oxygen to reduce contact resistance with
In an argon atmosphere at 550 ° C for 50 minutes
Was performed.

Subsequently, a part of the epitaxial growth layer at the other corner of the element where the n-type ohmic electrode was to be formed was removed by dry etching to expose the n-type contact layer 4 made of GaN. . Then, a nickel thin film 15 and an aluminum thin film 16 are formed on the exposed surface of the n-type contact layer 4 made of GaN by vacuum evaporation.
Were sequentially formed. For vacuum evaporation, a vacuum evaporation apparatus equipped with two resistance heating boats was used. One of the boats was loaded with a nickel piece as an evaporation source, and the other was loaded with an aluminum piece. 3.99 × 1 inside the vacuum evaporation system
The pressure was reduced to 0 ^-4 Pa, and the boat on which the nickel pieces were placed was first heated and heated to confirm that the nickel on the boat had dissolved, and then the shutter that separated the boat from the substrate was opened. Then, nickel deposition was started. The vapor deposition was performed while monitoring the film thickness of the vapor deposition film with a quartz vibrating plate type film thickness meter. When the film thickness reached 100 nm, the shutter was closed to stop the energization of the boat, and the vapor deposition of the nickel thin film 14 was completed. Subsequently, a current is applied to the board on which the aluminum is placed, and the aluminum thin film 1 having a thickness of 700 nm is formed according to the same procedure.
5 was formed. Finally, in order to obtain an ohmic junction of the n-type electrode, annealing was performed at 550 ° C. for 10 minutes in a nitrogen atmosphere to complete an n-type electrode 19 having a two-layer structure of nickel and aluminum.

The epitaxial wafer having the light-transmitting electrode 17 and the n-type electrode 18 as described above is
The chip was cut into corner chips, mounted on a lead frame, and each electrode was connected to the lead frame with an aluminum wire using an ultrasonic wire bonder. At the time of wire bonding, peeling of the n-type electrode was hardly observed. The percentage of chips damaged by bonding was about 7%. The chip thus obtained was molded with a resin to obtain a light emitting element lamp. When an operating current was applied between the bonding pad 18 and the n-type electrode 19 of this light emitting device lamp, the light emission output at a current of 20 mA was 3.3 mW on average, the forward voltage was 3.5 V, and the light emission wavelength was 470 nm. Luminescence was obtained. In addition, diameter 2
16,000 chips were obtained from an inch epitaxial wafer.

(Comparative Example) A light-emitting device lamp having the same structure as that of the embodiment described above in the epitaxial growth layer and a single-layer structure of a titanium-aluminum alloy similar to the conventional one in the structure of the n-type electrode was manufactured. When an operating current was applied between the electrode and the n-type electrode, a light emission output at a current of 20 mA was 3.3 mW on average, a forward voltage was 3.4 V, and blue light emission having a light emission wavelength of 470 nm was obtained. Further, when 16,000 chips were produced on an epitaxial wafer having a diameter of 2 inches, 30% of the chips were rejected due to peeling of the n-type electrode in the bonding step.

[0028]

According to the n-type electrode structure of the present invention, since the bondability is good, the product acceptance rate is high, and the contact resistance is low and the forward voltage is somewhat high, but there is no problem in practical use.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a group III nitride semiconductor light emitting device of an example.

FIG. 2 is a schematic sectional view taken along line AA ′ of FIG.

FIG. 3 is a schematic cross-sectional view of a conventional light emitting device having an AlGaInN-based double heterojunction structure.

[Explanation of symbols]

1, 31 ... substrate, 2, 32 ... buffer layer, 3 ...
Low n-doped GaN layer, 4,33 ... n-type contact layer, 5 ... lower cladding layer, 6, 34 ... light emitting layer,
7: diffusion prevention layer, 8: p-type layer, 9: p-type contact layer, 10: gold thin film, 11:・ Silicon dioxide thin film, 12: titanium thin film, 13: aluminum thin film, 14: gold thin film, 15: nickel thin film, 1
6 ... Aluminum thin film, 17 ... Translucent electrode, 1
8 bonding pad, 19 n-type electrode 2
0, 30... III-nitride semiconductor light emitting device, 21.
.Ball-shaped gold, 22... Bonding wire, 3
5 upper clad layer 36 p-type contact layer 37 nickel oxide thin film 38 gold thin film
39... P-type electrode pad, 40... N-type electrode

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mineo Okuyama 1-1-1, Onodai, Chiba City, Chiba Prefecture F-term in Showa Denko KK R4M104 AA04 AA10 BB02 BB05 BB09 BB13 BB14 CC01 DD16 DD28 DD34 DD64 DD65 DD78 EE15 FF17 GG04 HH08 HH15 5F041 AA03 AA04 AA43 AA44 CA05 CA12 CA34 CA40 CA65 CA73 CA83 CA92 CA98 DA07

Claims (7)

[Claims] 1. An n-type electrode for a light-emitting element, comprising a nickel (Ni) thin film and an aluminum (Al) thin film sequentially laminated on an n-type group III nitride semiconductor surface. 2. The n-type electrode for a light-emitting device according to claim 1, wherein the n-type group III nitride semiconductor is n-type GaN. 3. The nickel (Ni) thin film has a thickness of 0.05.
3. The n-type electrode for a light emitting device according to claim 1, wherein the thickness is from 1 μm to 3 μm. 4. An aluminum (Al) thin film having a thickness of 0.1 mm.
The n-type electrode for a light emitting device according to any one of claims 1 to 3, wherein the thickness is 4 to 2 µm. 5. A nickel (Ni) thin film having a thickness of 0.05 to 1 μm on a surface of an n-type group III nitride semiconductor and a nickel (Ni) thin film having a thickness of 0.5 to 1 μm.
A method for manufacturing an n-type electrode for a light emitting device, comprising sequentially laminating aluminum (Al) thin films of 4 to 2 μm and annealing at a temperature of 400 to 600 ° C. 6. A light emitting device comprising a light emitting layer made of a group III nitride semiconductor on a substrate, wherein the light emitting device according to claim 1 is provided on a surface of an n-type group III nitride semiconductor. Characterized by comprising an n-type electrode for
Group III nitride semiconductor light emitting device. 7. The light emitting layer is made of InGaN or InGaN.
7. The group III nitride semiconductor light emitting device according to claim 6, wherein the device has a multiple quantum well (MQW) structure composed of GaN and GaN.