JP2001320087A - Method for producing gallium nitride compound semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an electrode having a low resistance ohmic contact layer. SOLUTION: At least a P type gallium nitride layer is grown on a substrate and an electrode layer is formed on the P type gallium nitride layer wherein the electrode layer is formed by steps for plating the P type gallium nitride with a layer of beryllium metal or an alloy thereof, proceeding to a diffusion step, diffusing beryllium metal or an alloy thereof into the P type gallium nitride layer, cleaning the surface, depositing a metal on the clean P type gallium nitride layer, and then proceeding to a high temperature processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a gallium nitride compound semiconductor.

[0002]

2. Description of the Related Art Compound semiconductor devices are widely used in the field of communications and displays. Recently, gallium nitride III-V compound semiconductors have been developed to meet the needs of blue light sources. Become. Gallium nitride III
The main component of the group V compound semiconductor is indium aluminum nitride, aluminum gallium nitride, aluminum indium gallium nitride, or the like.

Conventionally, the most effective substrate used for a gallium nitride-based III-V compound semiconductor is a single crystal substrate of dialuminum trioxide. However, since this substrate cannot conduct, it is difficult to manufacture an element such as a light emitting diode. The positive electrode and the negative electrode must be formed on the same plane, and must be connected to the P-type layer and the N-type layer of the light emitting diode via an ohmic contact layer. Since the general electrode is made of a metal material, the thickness of which is considerably thin and light shielding is avoided, the electrical characteristics of the ohmic contact layer greatly affect the function of the light emitting diode made of the compound semiconductor. In particular, since the hole mobility of the P-type layer of gallium nitride in this type of semiconductor device is low, the resistance of the P-type layer is high, so that the diffusion of the hole flow is a key point in device manufacture.

[0004] US Patent No. 5,563,422 Japan N
The invention proposed by the icia company is a gallium nitride-based III
A method for manufacturing a group V compound semiconductor is provided. It plating the metal thin film on the P-type layer and performing annealing treatment to enhance the diffusion of hole flow, and hydrogen atoms linking with the acceptor are separated from the acceptor during the annealing process, thereby activating acceptor impurities. Thus, the electrical characteristics of the ohmic contact layer can be improved. However, in general, metals such as nickel, chromium, aluminum and gold have not clearly improved the efficiency and resistance of their ohmic contact points in the gallium nitride of the P-type layer.

[0005]

SUMMARY OF THE INVENTION Accordingly, it is a main object of the present invention to provide a method for manufacturing an electrode of a gallium nitride-based compound semiconductor device capable of improving the electrical characteristics of an ohmic contact layer.

[0006]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a method for diffusing beryllium ions into a gallium nitride P-type layer by a diffusion method to increase the hole mobility and to improve the subsequent manufacturing process. To provide a method for manufacturing a gallium nitride compound semiconductor in which an electrode having an ohmic contact layer with low resistance is obtained by adding an electrode to the gallium nitride compound semiconductor.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a view showing an element structure according to a method of manufacturing a gallium nitride-based compound semiconductor according to the present invention. The method for producing a gallium nitride-based compound semiconductor of the present invention is an improvement of a P-type electrode of a gallium nitride-based compound semiconductor device (for example, a gallium nitride-based light-emitting diode). As shown in the figure, the gallium nitride light emitting diode has a substrate 10
0 has an N-type gallium nitride layer 110 and a P-type gallium nitride layer 120 superposed thereon. Among them, the substrate 100 is made of a monocrystalline aluminum trioxide substrate to improve the efficiency. Since it does not conduct, the electrodes of the light emitting diode must be formed in front of the device. As shown in the figure, after forming an N-type gallium nitride layer 110 and a P-type gallium nitride layer 120 overlaid thereon, N-type gallium nitride is formed by reactive ion etching.
The P-type gallium nitride layer 110 and the P-type gallium nitride layer 120 superposed thereon are corroded into a planar trapezoid. Since the hole mobility of the P-type gallium nitride layer is low, the resistance of the P-type layer is improved, so that the P-type electrode 122 is formed on the entire P-type gallium nitride layer 120, and then the P-type electrode 122 is formed on the P-type electrode 122. Type electrode welding pad 1
24 and the exposed N-type gallium nitride layer 1
An N-type electrode 112 is formed on 10, and leads are provided to the N-type electrode 112 and the P-type electrode welding pad 124 to form a passage.

[0009] Because of the low hole mobility of the P-type gallium nitride layer, the gist of the present invention is to provide an electrode manufacturing method to improve the hole mobility and form an electrode having an ohmic contact layer with low resistance. Improve the efficiency of gallium compound semiconductor devices. FIG. 2 is a flowchart of a specific embodiment of the method for manufacturing a gallium nitride-based compound semiconductor according to the present invention. The method of the present invention includes the following steps: (1) Plating a P-type gallium nitride layer (P-type layer) with beryllium metal or an alloy thereof (for example, beryllium gold alloy). (2) Place in a high-temperature nitrogen environment for 3 to 15 minutes to diffuse beryllium into the P-type gallium nitride layer, and then clean the surface. (3) A 30-50 A nickel and a 70-150 A beryllium alloy are deposited and subjected to a high-temperature treatment under a nitrogen environment for 3 to 15 minutes to form a transparent conductive film. In the steps (1) and (2), it is preferable that the diffusion and the high-temperature treatment are performed within a range of 400 to 600 degrees Celsius.

FIG. 3 is a diagram showing the measurement results of the resistance of the electrode manufactured according to the present invention. In the case of the manufacturing process in which the beryllium diffusion manufacturing process is not performed, the resistance value of the electrode is 6.25 ohm, and when the beryllium diffusion manufacturing process according to the present invention is added, the resistance of the electrode becomes 1.25 ohm, and the original It becomes 1/5. Therefore, according to the present invention, the resistance of the ohmic contact layer of the P-type gallium nitride layer can be significantly reduced, and the efficiency of the light emitting diode can be improved.

[0011]

As described above, according to the method for manufacturing a gallium nitride-based compound semiconductor of the present invention, the resistance of the ohmic contact layer of the p-type gallium nitride layer can be greatly reduced, and the efficiency of the light emitting diode can be improved. it can.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration of an application element of a method for manufacturing a gallium nitride compound semiconductor according to the present invention.

FIG. 2 is a flowchart of a specific example of a method for manufacturing a gallium nitride-based compound semiconductor according to the present invention.

FIG. 3 is a diagram showing a measurement result of resistance of an electrode manufactured according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 100 Substrate 110 N type gallium nitride layer 112 N type electrode 120 P type gallium nitride layer 122 P type electrode 124 P type electrode welding pad

Claims (6)

[Claims] At least a P-type gallium nitride layer is grown on a substrate, and an electrode layer is formed on the P-type gallium nitride layer, wherein the P-type gallium nitride layer has a layer of beryllium metal or an alloy thereof. And then proceed with the diffusion step to diffuse the beryllium metal or its alloy into the P-type gallium nitride layer, then clean the surface, and then deposit the metal on this clean P-type gallium nitride layer and then heat treat A method of manufacturing a gallium nitride compound semiconductor formed by each of the following steps. 2. A method for manufacturing a gallium nitride compound semiconductor, wherein the beryllium alloy is a beryllium gold alloy. 3. The method according to claim 1, wherein the diffusing step comprises:
The method according to claim 1, wherein the semiconductor substrate is placed in a high-temperature nitrogen atmosphere at 0 degrees for 3 to 15 minutes. 4. The method of claim 1, wherein the deposited metal is a 30-50 A nickel and 70-150 A beryllium gold alloy. 5. The method according to claim 1, wherein the high-temperature treatment is performed in a nitrogen environment at 400 degrees Celsius.
The method for producing a gallium nitride compound semiconductor according to claim 1, wherein the high-temperature treatment is performed at -600 degrees for 3 to 15 minutes. 6. The method according to claim 1, wherein the substrate is a single crystal substrate of dialuminum trioxide.