JPS6298721A - Zn solid-state diffusing method for iii-v compound semiconductor - Google Patents

Abstract

PURPOSE:To prevent the deterioration in element characteristics by a method wherein, after a Zn-doped oxide film and an SiO2 cap have been continuously deposited on the surface of a III-V compound semiconductor by performing a sputtering method, Zn is diffused in the vicinity of the substrate surface by performing a heat treatment using the Zn-doped oxide film as the source of diffusion. CONSTITUTION:After a Zn-doped oxide film and an SiO2 cap have been deposited continuously on the surface of an N-type III-V compound semiconductor by performing a sputtering method, a heat treatment is performed, and Zn is diffused in the vicinity of the substrate surface using the Zn-doped oxide film as the source of diffusion. As a result, Zn can be diffused easily in the N-type III-V compound semiconductor by performing a low temperature process, and an excellent P-N junction can be formed in the vicinity of the surface of the III-V compound semiconductor.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to the use of Zn in a ■-■ group compound semiconductor such as GaAs.
This paper relates to improvements in solid-phase diffusion methods.

[Prior art]

Z to ■-V group semiconductors used in light emitting and light receiving elements, etc.
As an n diffusion method, a method is conventionally known in which a Zn-doped oxide film formed by plasma CVD is used as a diffusion source.

[Problem that the invention attempts to solve]

However, in order to obtain a high-quality film in such a method, a high temperature (usually 300° C. or higher) is required during film formation, which tends to deteriorate device characteristics.

The present invention was made to solve the above-mentioned problems, and it is an object of the present invention to provide a Zn solid-phase diffusion method capable of diffusing Zn into a ■-■ group compound semiconductor by a low-temperature process.

C) Means and operation for solving problems) The present invention provides n
After successively depositing a Zn-doped oxide film and a SiO2 cap on the surface of the type ■-■ group compound semiconductor by sputtering, heat treatment is performed to diffuse Zn into the semiconductor using the Zn-doped oxide film as a diffusion source. It is characterized by being diffused near the surface. According to the present invention, Zn can be easily diffused into the n-type IV group compound semiconductor by a low-temperature process, and a good pn junction can be formed near the surface of the ■-V group compound semiconductor.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

First, an n-type GaAs substrate 1 (n=I x 10')
A Zn-doped oxide film 2 and a cap 3 of SiO2 were successively formed by sputtering on the Zn-doped oxide film 2 and the cap 3 of SiO2. Z
The thickness of the n-doped oxide film 2 is 500 to 2000
The thickness of the cap 3 is 500. Next, N
2 gas at a temperature of 500 to 800°C for 1 hour to remove Zn from the Zn-doped oxide film 2 as a diffusion source.
A p-type diffusion layer was formed by diffusing n into the vicinity of the surface of the substrate 1.

After the diffusion, the substrate was folded and stainless steel etched, and the diffusion depth versus diffusion temperature was measured, and the characteristic diagram shown in FIG. 2 was obtained. Note that A in FIG. 2 is a characteristic line according to the present invention, and B is a characteristic line showing the relationship between diffusion temperature and diffusion depth according to the conventional vapor phase diffusion method. As is clear from FIG. 2, in the solid phase diffusion method of the present invention, a diffusion layer with a diffusion depth of, for example, 1 μm can be formed by heat treatment at 550°C, whereas in the vapor phase diffusion method, a diffusion layer with the same depth can be formed. 650-70 layers
It can be seen that a heat treatment temperature of 0°C is required and the temperature can be lowered by about 100°C. Moreover, the GaAs surface was in a mirror-like state after the cap and the Zn-doped oxide film were removed.

〔Effect of the invention〕

As detailed above, according to the present invention, it is possible to provide a method for solid-phase diffusion of Zn into a ■-v group compound semiconductor, which is capable of diffusing Zn into a ■-v group compound semiconductor using a low-temperature process, and which has excellent mass productivity.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a GaAs substrate used in the Zn solid-phase diffusion process in an example of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between diffusion temperature and diffusion depth. DESCRIPTION OF SYMBOLS 1... GaAs substrate, 2... Zn doped oxide film, 3... Cap.

Claims (1)

[Claims] Zn is deposited on the surface of the III-V compound semiconductor by sputtering.
A III-V compound semiconductor characterized in that after successively depositing a doped oxide film and a cap of SiO_2, a heat treatment is performed to diffuse Zn near the semiconductor surface using the Zn-doped oxide film as a diffusion source. Zn solid phase diffusion method.