JPS6242571A - Manufacture of compound semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a gate from peeling off by providing a heat resistant gate of metal silicide on a heated GaAs substrate. CONSTITUTION:A GaAs substrate 5 is put on a supporting saucer 6 which is supported on a table 7 and placed directly below a target 3. High vacuum is provided in a bell-jar 1 and the substrate 5 is heated 8 to the temperature of 120 deg.C. Then Ar gas is introduced into the bell-jar 1 and plasma is induced with Ar ions and the target 3 is sputtered by plasma discharge to deposit a heat resistant gate 4 of TaW silicide on the substrate 5. Adhesiveness between the gate metal and the substrate can be improved by heating the substrate so that the peeling off of the gate caused in the high temperature treatment after ion implantation by the difference between the thermal expansion coefficient of the gate metal and that of the substrate can be avoided and the performance of the device can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a compound semiconductor device.

BACKGROUND OF THE INVENTION In recent years, compound semiconductor devices have attracted attention because they can realize integrated circuits that take advantage of the characteristics of compound semiconductors, such as high-speed operation and low power consumption. The so-called self-line process, in which selective ion implantation is performed using a heat-resistant gate metal formed on a compound semiconductor substrate as a mask, and the implanted ions are activated by heat treatment at high temperatures to form a field effect transistor, improves the performance of compound semiconductor devices. This technology is attracting attention as a technology that can further improve it. However, since the compound semiconductor and the heat-resistant gate metal have different coefficients of thermal expansion, when selective ion implantation is performed on the compound semiconductor substrate on which the heat-resistant gate metal is formed and heat treatment is performed at a high temperature, stress due to the difference in the coefficient of thermal expansion between the two occurs. occurs, and the stress induces peeling of the heat-resistant gate metal, causing a significant deterioration in the performance of the compound semiconductor device.

Hereinafter, a conventional method for manufacturing a compound semiconductor device as described above will be described with reference to the drawings.

FIG. 2 shows a conceptual diagram of a process for forming a heat-resistant gate metal of a conventional compound semiconductor device. In Figure 2, 1
The Pelger, a high-frequency sputtering device, works to keep the inside of the container airtight. 2 is a target cover for protecting the target metal 3. 3 is a tantalum tungsten silicide target for forming a mental tungsten silicide gate metal 4 on a gallium arsenide substrate 5. Reference numeral 4 denotes a tantalum tungsten silicide heat-resistant gate metal that forms a Njot-Key junction between the gallium arsenide substrate 5 deposited on the gallium arsenide substrate 6. 6 is a substrate support plate on which the gallium arsenide substrate 5 is placed. Reference numeral 7 denotes a support base for fixing the substrate support plate 6. 9 is a substrate cooling water conduit for keeping the gallium arsenide substrate 5 at room temperature.

A process for forming a heat-resistant gate metal of the compound semiconductor device configured as described above will be described.

First, the gallium arsenide substrate 5 is placed on the substrate support plate 6.

A substrate support plate e is placed on a support stand 7, and the support plate 6 is set so that the target 3 is directly above the gallium arsenide substrate 5. Next, after creating a high vacuum inside the Pelger 1, water is flowed through the substrate cooling water conduit 9 to keep the gallium arsenide substrate 5 at room temperature. Finally, argon gas is introduced into the Pelger 1 to induce plasma discharge by argon ions,
The target 3 is sputtered by this plasma discharge to form a mental tungsten silicide heat-resistant gate metal 4 on the gallium arsenide substrate 5.

Problems to be Solved by the Invention However, in the above structure, in the high temperature heat treatment process after selective ion implantation between the formed tantalum tungsten silicide heat-resistant gate metal 4 and the gallium arsenide substrate 5, due to the difference in thermal expansion coefficient. The generation of stress causes peeling of the tantalum tungsten silicide heat-resistant gate metal 4, which has the drawback of significantly reducing the performance of the compound semiconductor device.

In view of the above drawbacks, the present invention provides a method for manufacturing a compound semiconductor device in which peeling does not occur even when a gallium arsenide substrate on which a mental tungsten silicide heat-resistant gate metal is formed is heat-treated at high temperature, and the performance of the compound semiconductor device does not deteriorate. It provides:

Means for Solving the Problems In order to solve the above problems, the method for manufacturing a compound semiconductor device of the present invention includes a step of heating a compound semiconductor substrate and a step of forming a heat-resistant gate metal on the heated compound semiconductor substrate. It is composed of.

Effect: This structure makes it possible to reduce the stress caused by the difference in thermal expansion coefficient between the compound semiconductor substrate and the heat-resistant gate metal, and also improves the crystallinity of the heat-resistant gate metal. Adhesion to the semiconductor substrate is improved, and peeling of the heat-resistant gate metal can be prevented in the high-temperature heat treatment step after selective ion implantation, and the performance of the compound semiconductor device can also be improved.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a conceptual diagram of a process for forming a heat-resistant gate metal of a compound semiconductor device in an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a Pelger of a high-frequency sputtering device, which serves to keep the inside of the container in a sealed state. 2 is a target cover for protecting the target 3. 3 is a tantalum tungsten silicide target for forming a tantalum tungsten silicide heat-resistant gate metal 4 on a gallium arsenide substrate ε. Reference numeral 4 denotes a tantalum tungsten silicide gate metal that forms a Schottky junction with the gallium arsenide substrate 6. 6 is a substrate support plate on which the gallium arsenide substrate 6 is placed. Reference numeral 7 denotes a support base for fixing the substrate support plate 6. 8 is a heater for heating the gallium arsenide substrate 6;

The operation of the heat-resistant gate metal forming process of the compound semiconductor device configured as described above will be described below.

First, the gallium arsenide substrate 6 is placed on the substrate support plate 6.

A substrate support plate 6 is placed on a support pedestal, and the support plate 6 is set so that the target 3 is directly above the gallium arsenide substrate 6. Next, after creating a high vacuum inside the Pelger 1, the gallium arsenide substrate 5 is heated to 120℃ using the heater 8 for heating the substrate.
Heat to 'C.

Finally, argon gas is introduced into the Pelger 1 to induce plasma with argon ions, and the target 3 is sputtered by this plasma discharge to form the tantalum tungsten silicide heat-resistant gate metal 4 on the gallium arsenide substrate 5.

As described above, according to this embodiment, by heating the gallium arsenide substrate 6 to 120°C, the tantalum tungsten silicide heat-resistant gate metal 4 and the gallium arsenide substrate 6 are heated.
We were able to improve the adhesion between the two. As a result, it is possible to prevent the peeling of the heat-resistant gate metal 4 that has conventionally occurred due to the difference in thermal expansion coefficient between the two in the high-temperature heat treatment step after selective ion implantation, and it is also possible to improve the performance of the compound semiconductor device. did it.

In addition, in the example, the substrate heating temperature was 120'C,
The substrate heating temperature is not limited to 120'C, but may be any temperature as long as it is above room temperature. For example, it can be set to 200°C. Also, any material may be used as long as it has heat resistance. For example, tungsten silicide can be used.

Effects of the Invention As described above, the present invention provides substrate heating of a compound semiconductor substrate during formation of a heat-resistant gate metal.
This improves the adhesion between the compound semiconductor substrate and the heat-resistant gate metal, eliminates the peeling of the heat-resistant gate metal that occurs due to the difference in thermal expansion coefficient between the two during the high-temperature heat treatment process after selective ion implantation, and improves the performance of compound semiconductor devices. Since it can be improved, its practical effects are significant.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a process for forming a heat-resistant gate metal of a compound semiconductor device according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram of a process of forming a heat-resistant gate metal of a conventional compound semiconductor device. 1... Pelger of sputtering equipment, 2...
...Target cover, 3...Tantalum tungsten silicide target, 4...Tantalum tungsten silicide gate metal, 6...Gallium arsenide substrate, 6...Substrate support plate ,7...
...Support stand, 8...Heater for heating the substrate, 9...
...Water conduit for board cooling.

Claims (2)

[Claims] (1) A method for manufacturing a compound semiconductor device, comprising the steps of heating a compound semiconductor substrate and depositing a heat-resistant gate metal on the heated compound semiconductor substrate. (2) The method for manufacturing a compound semiconductor device according to claim 1, wherein the compound semiconductor substrate is a gallium arsenide substrate, and the heat-resistant gate metal is a metal silicide.