JP2002314131A - Transparent electrode, manufacturing method thereof and group iii nitride semiconductor light emitting element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a p-type electrode superior in light transmission for group III nitride semiconductor light emitting elements and a group III nitride semiconductor light emitting element utilizing the same. SOLUTION: A thin film of gold simple substance is formed on a p-type group III nitride semiconductor surface and the surface of the gold thin film is protected with a silicon dioxide thin film to form a light-transmitting p-type electrode. The silicon dioxide thin protective film covering the gold thin film prevents gold from balling up even in an annealing process for obtaining an Ohmic junction, thereby obtaining a high light transmission.

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 and a light emitting device such as a laser device which are used as a blue light emitting device.
The present invention relates to a structure of a light-transmitting electrode provided on a light extraction side of a light-emitting element in which a group-III nitride semiconductor is stacked, and further relates to a group-III nitride semiconductor light-emitting element using the light-transmitting electrode structure.

[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 _0.9 N p-type upper cladding layer 35, and magnesium-doped p-type Ga on the p-type upper cladding layer 35.
A p-type contact layer 36 of N is sequentially epitaxially grown to form a stacked body.

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. In the example of the light emitting device shown in FIG. 3, a gold thin film 37 is formed on the surface of the p-type contact layer 36.
A translucent electrode having a two-layer structure of a nickel oxide thin film 38 and a conductive nickel oxide thin film 38 is provided, and a p-type electrode pad 39 is formed on the surface of the nickel oxide thin film 38. On the other hand, the n-type electrode serving as a counter electrode is formed on the surface of the n-type contact layer 33 made of GaN, in which a part of the stacked body composed of the epitaxial growth layer is removed by etching and exposed. 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. 3, the n-type electrode 40 made of an aluminum film is formed on the surface of the n-type contact layer 33. The bonding wire 22 is connected by welding the ball-shaped gold 21 using a wire bonder.

Conventionally, 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
For example, it has excellent ohmic properties, high external quantum efficiency, and high brightness.
It is said that a light emitting element can be obtained.

On the other hand, as an n-type electrode formed on the surface of the 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.

[0006]

However, the p-type I
As a light-transmitting electrode formed on the group II nitride semiconductor contact layer, a light-transmitting electrode having a two-layer structure including a first layer made of a metal thin film and a metal oxide conductive film has a light emission transmittance of usually 4%.
It is as low as about 0 to 60%, which is insufficient as a light emitting element.
This is considered to be due to a decrease in transmittance due to the metal oxide conductive film. However, for the purpose of improving transmittance,
If a light-transmitting electrode made of only gold was used without forming a metal oxide conductive film, during annealing for the purpose of reducing contact resistance, a break called ball-up occurred, or in the electrode forming process, During handling, there is a problem that the yield of the element is remarkably reduced due to rubbing and damage.

The present invention has been made in view of the above circumstances, and is directed to a light-transmitting electrode formed on a p-type group III nitride semiconductor contact layer, which has a high light transmittance from the light-emitting layer, and An object of the present invention is to provide a light-transmitting electrode structure that does not require a simple annealing step and that can obtain a sound light-transmitting electrode.

[0008]

The translucent electrode of the present invention comprises:
A translucent electrode was formed by sequentially laminating a gold (Au) thin film and a silicon dioxide (SiO ₂ ) thin film on the surface of a p-type group III nitride semiconductor. With the above configuration of the translucent electrode, the p-type
By forming a good ohmic contact between the group III nitride semiconductor and Au and covering the Au thin film with a stable SiO ₂ protective film, a ball-up phenomenon does not occur in the mild annealing process required for ohmic contact formation. As a light-transmitting electrode having a high light transmittance of 70 to 90%.

The light-transmitting electrode of the present invention can be applied to a case where the p-type group III nitride semiconductor is p-type GaN. GaN is easily lattice-matched with a group III nitride semiconductor including another light emitting layer to obtain high-quality crystals, and it is easy to obtain a p-type semiconductor layer by selecting a dopant.
It is useful as a contact layer of a group II nitride semiconductor light emitting device.

In the translucent electrode of the present invention, it is preferable that the thickness of the Au thin film is 0.003 to 1 μm. More preferably 0.005 to 0.1 μm, even more preferably 0.1 to 0.1 μm.
008 to 0.02 μm. It is preferable that the thickness of the SiO ₂ thin film is 0.5 to 3 μm. More preferably, the thickness is 0.5 to 1.5 μm. This is because current is diffused over the entire light emitting region of the light emitting layer, and high light transmittance is obtained.

The method for producing a translucent electrode according to the present invention is a p-type
0.003 to 1 μm thick gold on the group II nitride semiconductor surface
(Au) a thin film and 0.5 to 3 μm thick silicon dioxide (S
iO _Two ) After the thin films are sequentially laminated, a temperature of 450 to 600 ° C.
The method of annealing at different degrees was adopted. Adopt such a method
By doing so, the transmittance of light from the light emitting layer is high, and
Breaking up called ball-up or electrode forming
During handling in the process
The problem is that the yield of the element is significantly reduced due to
No sound translucent electrode can be obtained.

In the light emitting device of the present invention, particularly, the light emitting layer
It is preferable to have a multiple quantum well (MQW) structure composed of nGaN or InGaN and GaN. In general, group III nitride semiconductors have a high band gap energy and can emit light of a short wavelength.
It is also very useful as a laser device capable of coping with a higher recording density of an optical disk. If the translucent electrode of the present invention is used for the group III nitride semiconductor light emitting device, it becomes possible to obtain a light emitting device having high light transmittance and higher external quantum efficiency. 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 the sapphire substrate at high temperature
A method of using a crystal lump obtained by nitriding nitrogen 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. The n-type contact layer
GaN using an n-type dopant such as silicon
And the like. The n-type contact layer has a light emitting structure on it
In addition to the above, a part is deleted as described later to form an n-type electrode.
Therefore, the thickness needs to be about 4 to 6 μm.

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 2.0-6.
At about 0 eV, laser emission of blue-violet or ultraviolet light having a wavelength shorter than 430 nm can be obtained from green-visible light or blue-visible light having a wavelength of about 530 nm. The light emitting structure of the present invention is configured by joining the above light emitting layers with cladding layers of different conductivity types. Normally, a cladding layer having a band gap energy higher than that of the light emitting layer is used to inject electrons into the light emitting layer and confine the injected electrons to promote pn 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 AlGaN is used.
It is preferable to provide a thin film made of GaN and GaN 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 layer on the p-side.
Since InGaN has a smaller band gap than GaN, InGaN has advantages such as easy formation of ohmic contact with metal and high p-carrier activity rate. The contact layer uniformly supplies an operating current to the entire surface of the light emitting element. The n-type and p-type contact layers are bonded to each other.
It must be lattice-matched with the group III nitride semiconductor and have a low specific resistance. On each of the n-type and p-type contact layers, n-type and p-type electrodes for forming a good ohmic junction for connection to an external power supply are provided.

A translucent p-type electrode is formed on the p-type contact layer in the light extraction direction. In the present invention, a translucent electrode having a two-layer structure in which a gold (Au) thin film and a silicon dioxide (SiO ₂ ) thin film are sequentially laminated is employed as the p-type electrode. The thickness of the gold thin film is suitably 0.003 to 1 μm. In general, it is known that even a metal can be translucent if it is a thin film,
In order to obtain a 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 is deposited on the gold thin film to a thickness of 0.5 to 2 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. After forming the gold thin film and the silicon dioxide thin film, annealing is performed at a temperature of 450 to 600 ° C. to form an ohmic contact. It is preferable that annealing is performed at a low temperature as much as possible and mild annealing is performed.

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 having a thickness of 0.5 to 1 μm.
Annealing is performed at a temperature of 00 ° C. to form an n-type electrode that makes ohmic contact.

[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 an InGaN well layer and a barrier layer of GaN; a diffusion prevention layer 7 composed of undoped AlGaN; a p-type layer 8 composed of p-type GaN; An epitaxial wafer in which the p-type contact layers 9 were sequentially laminated was manufactured. The growth of the buffer layer 2 and the low n-doped GaN layer 3 made of GaN is performed using trimethylgallium ((CH ₃ ) ₃ Ga).
/ Ammonia (NH ₃ ) mixed gas was used as a source gas. To grow the n-type contact layer 4 made of n-type GaN, trimethylgallium ((C
A mixed gas of H ₃ ) ₃ Ga) / ammonia (NH ₃ ) was used, and a mixed gas of disilane (Si ₂ H ₆ ) / hydrogen (H ₂ ) was used as a dopant. 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. As a dopant, disilane (Si ₂ H ₆ )
/ Hydrogen (H ₂ ) mixed gas was used.

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

On the surface of the p-type contact layer 9 of InGaN of the epitaxial wafer formed as described above, a gold (Au) thin film 10 and a silicon dioxide thin film 11 were formed to form a translucent electrode 17. Then, a part of the silicon dioxide thin film 11 is removed by etching, and titanium (Ti) is formed as a bonding pad 18 at one corner of the (Au) thin film 10.
Thin film 12, aluminum (Al) thin film 13 and gold (A)
u) Three layers of vapor-deposited films composed of the thin films 14 were sequentially formed.
The formation of the translucent electrode 17 and the bonding pad 18
This 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, a solution of gel-like silicon dioxide (SiO ₂ ) dissolved in an organic solvent is applied on the gold vapor-deposited film by a spin coating method, and heat-treated in an inert atmosphere to form a film. A silicon dioxide thin film 11 made of SiO ₂ having a thickness of 1.7 μm was formed. Further, the silicon dioxide thin film 11 was patterned by using a general photolithography technique, and an opening of the silicon dioxide thin film 11 was provided at a position to be a corner of a rectangular element on the epitaxial wafer. Further, as a bonding pad 18 for wire bonding, a three-layer deposited film made of titanium (Ti), aluminum (Al), and gold (Au) was sequentially formed on the entire surface of the epitaxial wafer. The thickness of each deposited film is as follows: Ti: 0.1 μm, Al: 0.5 μm, A
u: 0.5 μm. Further, the three-layer deposited film is patterned by using a normal photolithography technique, and the three-layer deposited film is left only at the position of the opening of the silicon dioxide thin film 11 to be a corner of the element. A portion of the deposited film was removed to form a bonding pad 18 for a p-type electrode. Finally, annealing was performed at 550 ° C. for 50 minutes in an argon atmosphere containing 10% oxygen in order to reduce the contact resistance between the p-type contact layer 9 made of InGaN and the translucent electrode 17.

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. . Next, a nickel thin film 15 and an aluminum thin film 16 were sequentially formed on the exposed surface of the n-type contact layer 4 by a vacuum evaporation method. The thickness of the nickel thin film 15 was 0.1 μm, and the thickness of the aluminum thin film 16 was 0.7 μm. Finally, in order to obtain an ohmic junction of the n-type electrode, 5
Annealing was performed at 50 ° C. for 10 minutes to complete the n-type electrode 19.

The epitaxial wafer having the translucent electrode 16 and the n-type electrode 19 as described above was
The chip was cut into m-shaped chips, mounted on a lead frame, and each electrode was connected to the lead frame with an aluminum wire using an ultrasonic wire bonder. Observation of the light-transmitting electrode of the chip thus obtained with an optical microscope revealed that the light-transmitting electrode portion was a uniform transparent film exhibiting a light blue color, and no dirt, peeling or ball-up was observed. Further, the light transmittance of a transparent electrode sample having a two-layer structure made of gold and SiO ₂ , which was prepared in the same procedure as that of the translucent electrode prepared in this example, was 70%. 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 17 and the n-type electrode 19 of this light emitting element lamp, the current 2
The emission output at 0 mA was 3.3 mW on average, the forward voltage was 3.5 V, and blue emission having an emission wavelength of 470 nm was obtained. In addition, 16,000 chips were obtained from an epitaxial wafer having a diameter of 2 inches, and the emission intensity was 2.
When chips less than 8 mW were removed as rejected products, the product yield was 98%.

(Comparative Example) The structure of the epitaxial growth layer was the same as that described in the embodiment, and the light-transmitting electrode had the same two-layer structure of nickel oxide (NiO) and gold (Au) as in the prior art. When an element lamp was manufactured and an operating voltage was applied between the p-type electrode and the n-type electrode, the emission output at a current of 20 mA was 2.4 mμW on average, and the forward voltage was 3.
At 4 V, blue light emission with an emission wavelength of 470 nm was obtained.
Also, 1 inch from an epitaxial wafer having a diameter of 2 inches
6,000 chips are obtained, and the emission intensity is 2.8 mW
After removing chips less than as rejects,
The product yield was 30%.

[0028]

According to the light-transmitting electrode structure of the present invention, since the transmittance of emitted light is high, a light-emitting element lamp having high external quantum efficiency and high brightness can be obtained when a lamp is formed. Although the forward voltage slightly increases, there is no problem in practical use. Further, in producing the light emitting device of the present invention, unlike the case where the light-transmitting electrode is formed only with a single layer of gold without forming silicon dioxide, the ball is used for annealing for the purpose of reducing the contact resistance. This does not cause a break called "up" or rubbing and damage during handling of the electrode forming process, so that the yield of the element is not significantly reduced.

[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 light emitting device having a conventional InGaN-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 ... gold thin film, 38 ... nickel oxide thin film,
39... P-type electrode pad, 40... N-type electrode

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Mineo Okuyama 1-1-1 Ohnodai, Chiba-shi, Chiba F-term in Showa Denko KK R4 (reference) 4M104 AA04 AA07 BB02 BB05 BB09 BB13 BB14 CC01 DD34 DD78 EE05 EE16 FF13 GG04 HH20 5F041 AA03 AA04 AA43 AA44 CA05 CA12 CA34 CA40 CA65 CA83 CA85 CA88 CA92 CA98 DA07

Claims (8)

[Claims] 1. The method according to claim 1, wherein gold (A) is formed on the surface of the p-type group III nitride semiconductor.
u) A translucent electrode comprising a thin film and a silicon dioxide (SiO ₂ ) thin film sequentially laminated. 2. The translucent electrode according to claim 1, wherein the p-type group III nitride semiconductor is p-type GaN. 3. A gold (Au) thin film having a thickness of 0.003 to 1
The translucent electrode according to claim 1, wherein the translucent electrode has a thickness of μm. 4. The translucent electrode according to claim 1, wherein the thickness of the silicon dioxide (SiO ₂ ) thin film is 0.5 to 3 μm. 5. A gold (Au) thin film having a thickness of 0.003 to 1 μm and a thickness of 0.5 to 1 μm on a surface of a p-type group III nitride semiconductor.
A method for manufacturing a light-transmitting electrode, comprising sequentially laminating a silicon dioxide (SiO ₂ ) thin film of 3 μm and annealing at a temperature of 450 to 600 ° C. 6. A light emitting device having a light emitting layer made of a group III nitride semiconductor on a substrate, wherein a p-type I
A group III nitride semiconductor light emitting device comprising the translucent electrode according to any one of claims 1 to 4 on a surface of the group II nitride semiconductor. 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. 8. The group III nitride semiconductor light emitting device according to claim 6, wherein the group III nitride semiconductor on which the translucent electrode is formed is InGaN.