JPS62141727A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form an insulating film whose composition is converted in a chemically stable state, by making a Ga2O3 insulating film formed on a substrate surface react at low temperature by an ammonia plasma process so that formation of a thermally deformed layer and an increase in surface level can be suppressed. CONSTITUTION:A thermally oxidizing film of Ga2O3 is formed on a GaAs substrate to process ammonia plasma. Thus, evaporation of As from a surface of the GaAs substrate and diffusion of Ga into an insulating film can be suppressed, and the insulating film on the surface of the GaAs substrate can be changed into a nitriding film. In case of an oxidizing film of Ga2O3 formed by positive pole oxidation method, a decrease in GaAs is similarly suppressed on the surface of GaAs to form an insulating film by superior conversion of composition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a semiconductor device including a step of using an insulating film formed on the surface of a GaAs compound semiconductor as a composition conversion film.

BACKGROUND OF THE INVENTION Conventionally, a Ga2O3 thermal oxide film formed on the surface of a G4As substrate is heat treated at a high temperature (eoo' or higher) in an ammonia atmosphere, and a part of the Ga2O3 thermal oxide film is made into a nitride film.

Problems to be Solved by the Invention FIG. 4 is a diagram showing the results of AES when the nitride film 3 was formed by conventional high temperature heat treatment in an ammonia atmosphere.

In FIG. 4, in the conventional high-temperature heat treatment method, Ga evaporates and Ga diffuses into the Ga2O3 thermal oxide film 2.
It can be seen that a thermally altered layer is formed on the surface of aAs 1, resulting in an increase in surface levels, making it unsuitable for use as an insulating film for a GaAs substrate.

Means for Solving the Problems The present invention aims to solve such problems, and G.A.A.S.
By subjecting the Ga2Q3 insulating film formed on the substrate surface to a low-temperature reaction using ammonia plasma treatment, GaA
This is to nitride the insulating film on the s-substrate.

Effect: By the method of manufacturing a semiconductor device of the present invention, GaAs
By suppressing the evaporation of As from the substrate surface, suppressing the diffusion of Qa into the insulating film, and converting the insulating film on the G p As substrate surface into a nitride film, the formation of a thermally altered layer and the surface state This makes it possible to form a chemically stable insulating film whose composition has been changed, thereby improving the yield in the manufacturing process of semiconductor devices.

EXAMPLE FIG. 1 is a diagram showing the relationship between the reaction time and the thickness of the nitride film when 1000 Ga2O3 thermal oxide films were formed on a GaAm substrate and treated with ammonia plasma.

In Figure 1, G
It can be seen that the nitride film on the a A m substrate is produced by diffusion control.

Figure 2 shows that 1000 Ga2O3 thermal oxide films 2 were formed on a GaAm substrate, and the ammonia flow rate was 15cc7.
ininin.

Substrate temperature: 360°C, AES when ammonia treated under the conditions of 2 reaction chamber pressures of 0.3 Torr and power of 100 W.
FIG.

In FIG. 2, 1 indicates the G, a A s substrate part,
It can be seen that the decrease in 88 and the decrease in Ga on the surface of the GaAs substrate 1 are suppressed. 2 indicates a Ga2O3 thermal oxide film portion, and 3 indicates a nitride film portion.

FIG. 3 shows Ga formed on the Ga Am substrate.
3 is a diagram showing the surface state concentration of GaAs when a 2O3 film is subjected to ammonia plasma treatment (4 in FIG. 3) and when it is subjected to a conventional high-temperature heat treatment in an ammonia atmosphere (5 in FIG. 3). FIG. .

In FIG. 3, it can be seen that the surface state concentration is lower when treated with ammonia plasma.

This is because the ammonia radical molecules generated by ammonia plasma diffuse through the Ga 2 (J3 thermal oxide film and a reaction occurs at low temperatures, so the composition of the Ga As surface does not change (the Ga 2 O 3 thermal oxide film is nitrided). This is because it can be done.

Furthermore, in the case of a Ga2O3 oxide film formed by the anodic oxidation method, the reduction of GaAs on the GaAs surface was similarly suppressed and an insulating film was formed with good compositional conversion.

Effects of the Invention By the method of manufacturing a semiconductor device of the present invention, G a A I
By suppressing the evaporation of As from the substrate surface, suppressing the diffusion of Ga into the insulating film, and changing the insulating film on the GaAs substrate surface to a nitride film, the formation of a thermally altered layer and the surface standardization are improved. This made it possible to form a chemically stable insulating film with a changed composition, thereby improving yields in the semiconductor device manufacturing process.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing the relationship between the reaction time of the upstream method of the present invention and the thickness of the nitride film produced when a G a 2 O a thermal oxide film is formed on a G, A m substrate. Figure 2 is a characteristic diagram showing the AES results according to the embodiment method of the present invention, and Figure 3 is the G a A of the embodiment method of the present invention and the conventional method.
FIG. 4 is a characteristic diagram comparing the surface states of B, and FIG. 4 is a characteristic diagram showing the results of AES using the conventional method. 1...GaAs, 2...C5a 2O
s, 3...Nitride film, 4...Line after ammonia plasma treatment, 5...Line of conventional example. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 θ 7ooo zooo
. A moat of surface forces? (A' Figure 3 Ec Et EV Nio7bo Band

Claims (3)

[Claims] (1) Forming an insulating film on one surface of the GaAs substrate includes a step of forming a Ga_2O_3 oxide film on one surface of the GaAs substrate, and a step of subjecting the Ga_2O_3 oxide film to ammonia plasma treatment at a low temperature. A method for manufacturing a semiconductor device. (2) The Ga_2O_3 oxide film on the GaAs substrate is formed by an anodic oxidation method or a thermal oxidation method.
A method for manufacturing a semiconductor device according to section 1. (3) GaAs substrate temperature with Ga_2O_3 oxide film is set to 5
2. The method of manufacturing a semiconductor device according to claim 1, wherein the ammonia plasma treatment is performed at a temperature of 00° C. or lower.