JPH0693454B2 - Method for manufacturing semiconductor device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device including a step of forming an insulating film on the surface of a compound semiconductor.

2. Description of the Related Art Conventionally, as a pretreatment for forming an insulating film on a compound semiconductor substrate, the substrate surface is washed with an organic solvent or an etching solution to directly form the insulating film.

Problems to be Solved by the Invention It is difficult to remove carbon and oxygen adhering to the surface by the conventional cleaning method, and when the insulating film is directly formed on the substrate surface, the surface depletion layer is easily formed. However, it is not suitable as a method for forming a surface protection film on a substrate or a method for forming a heat treatment protection film.

Means for Solving the Problems The present invention aims to solve such problems, and after cleaning the substrate surface, the substrate is placed in a plasma reaction chamber, ammonia plasma treatment is performed to nitride the GaAs surface, and then an insulating film is deposited. To do.

By the method for manufacturing a semiconductor device of the present invention, the adhesion between the compound semiconductor and the insulating film is strengthened, the surface level of the compound semiconductor surface formed by the insulating film is suppressed, and the field effect transistor etc. It is possible to provide a semiconductor device that suppresses performance deterioration and has a high yield.

Example Hereinafter, a method for manufacturing a semiconductor device of the present invention will be described based on an example.

FIG. 1 shows an embodiment of the present invention.

In FIG. 1, the surface-cleaned GaAs substrate 1 is placed on the susceptor 3 of the parallel plate type plasma CVD apparatus 2,
The reaction chamber 4 is replaced with ammonia for about 5 minutes. The RF power supply for plasma generation is input, the reaction chamber is converted to ammonia plasma, and left for about 10 minutes to nitride the GaAs substrate display.
Then, silane gas is mixed with ammonia gas to deposit a silicon nitride film on the surface of the GaAs substrate.

Figure 2 shows the results of XPS analysis of the GaAs surface using ammonia plasma.

From FIG. 2, comparing the ammonia plasma-treated substrate (line A in FIG. 2) and the untreated substrate (line B in FIG. 2), the natural oxide film AS ₂ O was observed in the untreated case. _Although only ₅ films were formed, GaN was formed when ammonia plasma treatment was performed.
The peak appears, indicating that GaN is formed by nitriding the GaAs surface.

Fig. 3 shows the time left in the ammonia plasma atmosphere and
The relationship between the film thicknesses of the GaN film formed on the GaAs substrate surface is shown.

In FIG. 3, the film thickness of the GaN film is proportional to the square root of time, and the formation of the GaN film is progressing due to diffusion control.

This ammonia plasma treatment is used as a pretreatment for forming an insulating film.

When ammonia plasma is used as a pretreatment for the insulating mask for ion implantation, the ion stopping power is increased and the lateral spread of the implanted ions at the interface of the implantation mask can be suppressed.

When ammonia plasma is used as a pretreatment for forming the interlayer isolation insulating film of the wiring of the semiconductor device, the interface between the substrate and the insulating film is inactivated, and the leak current can be suppressed.

Similarly, the surface leak current can be suppressed when the ammonia plasma treatment is performed at the time of forming the surface protective film.

Similarly, the inter-electrode leakage current can be suppressed even when the ammonia plasma treatment is performed at the time of forming the inter-electrode separation protection film of the semiconductor device.

Further, when the ammonia plasma treatment is performed at the time of forming the heat treatment protective film, the stress at the interface between the substrate and the protective film is relieved, and the generation of the thermal conversion layer can be suppressed.

In this embodiment, no film is formed on the substrate in advance, but an insulating film such as a silicon oxide film may be attached to the substrate. This is because, as shown in FIG. 3, since the reaction is diffusion-controlled, ammonia radicals diffuse in the insulating film and the substrate interface is inactivated.

EFFECTS OF THE INVENTION According to the present invention, by performing an ammonia plasma treatment on a compound semiconductor surface, nitriding the semiconductor surface, and then continuously forming an insulating film, the adhesion between the compound semiconductor and the insulating film is strengthened, and The surface level of the compound semiconductor surface to be formed is suppressed, performance deterioration of the field effect transistor and the like formed on the surface is suppressed, and a semiconductor device with high yield can be provided, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a sectional view of a plasma CVD apparatus showing an embodiment of the present invention, FIG. 2 is a view showing the result of XPS analysis of the GaAs surface by the ammonia plasma of the present invention, and FIG. 3 is left in an ammonia plasma atmosphere. FIG. 4 is a diagram showing a relationship between time and a film thickness of a GaN film formed on the surface of a GaAs substrate. 1 ... GaAs substrate, 2 ... Plasma CVD apparatus, 3 ... Susceptor, 4 ... Reaction chamber.

Claims (8)

[Claims] 1. In the step of forming an insulating film on a compound semiconductor substrate, ammonia plasma treatment is performed before forming the insulating film to nitride the surface of the compound semiconductor,
A method of manufacturing a semiconductor device, comprising a step of continuously forming an insulating film on the surface of the compound semiconductor. 2. A method for manufacturing a semiconductor device according to claim 1, wherein nitride is formed on the surface of the compound semiconductor by performing plasma treatment. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the ammonia plasma treatment and the formation of the insulating film are performed in the same reaction chamber. 4. The method of manufacturing a semiconductor device according to claim 1, wherein ammonia plasma treatment is performed as a pretreatment for forming an insulating film for an impurity diffusion mask or an ion implantation mask. 5. The method of manufacturing a semiconductor device according to claim 1, wherein ammonia plasma treatment is performed as a pretreatment for forming an interelectrode separation protection film of the semiconductor device. 6. The method of manufacturing a semiconductor device according to claim 1, wherein ammonia plasma treatment is performed as a pretreatment for forming an interlayer isolation insulating film on the wiring of the semiconductor device. 7. The method of manufacturing a semiconductor device according to claim 1, wherein an ammonia plasma treatment is performed as a pretreatment for forming an insulating protective film for heat treatment. 8. The method of manufacturing a semiconductor device according to claim 1, wherein an ammonia plasma treatment is performed as a pretreatment for forming the surface protective film.