JPH0521354A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To remove a spontaneous oxide film on a surface of a substrate without heating an Si substrate body by irradiating the substrate with an ultraviolet ray from an excimer laser to be turned ON, OFF in an extremely short time of one second or less. CONSTITUTION:An Si substrate 2 is introduced into a reaction chamber 1, and irradiated with only one pulse of an ultraviolet ray by a KrF excimer laser 3. A laser beam energy is 500mJ/cm<2>, an H2 flow rate is 3 SLM, and an H2 pressure is 1Torr. Then, an SiGe film is grown 1000Angstrom . The conditions at this time have 580 deg.C of a substrate temperature, 5 SCCM of Si2H6 flow rate, 3 SCCM of GeH4 flow rate, 3 SLM of H2 flow rate, and 1Torr of reaction pressure. This film was an epitaxial film. Variation in n-type/n<+> type boundary due to a laser irradiation was the resolution of less of a secondary ion mass spectrum analysis. That is, only the surface of the Si substrate is heated, the oxide film can be removed, the interior of the substrate is hot heated, and hence semiconductor characteristics are not deteriorated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing method, particularly S
The present invention relates to a method for removing a natural oxide film formed on the surface of a substrate.

[0002]

2. Description of the Related Art Conventionally, a natural oxide film is removed before growing a thin film on a Si substrate by heating it to 800 ° C. or higher in an ultrahigh vacuum or a reducing gas. When the entire substrate is heated to such a high temperature, the characteristics of the device are deteriorated, such as the diffusion of the n / n ⁺ interface, and it is an obstacle to miniaturization.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to heat only a natural oxide film formed on the surface of a Si substrate to a high temperature.

[0004]

The above-mentioned problems are characterized by including the step of irradiating the Si substrate with ultraviolet rays that can be turned on and off in an extremely short time of 1 second or less to remove the natural oxide film on the Si substrate. It can be solved by the method of manufacturing a semiconductor device.

[0005]

When light is incident on the semiconductor, the shorter the wavelength of the light is, the more the light is absorbed by the incident layer and is not transmitted to the inside. Moreover, the shorter the irradiation time, the less the temperature rise inside. If the irradiation time exceeds 1 second, the internal temperature rises. Among the ultraviolet rays, for example, the ultraviolet rays by the KrF excimer laser have a pulse of about 1 × 10 ⁻⁷ seconds, and only the natural oxide film on the surface of the Si substrate can be evaporated. Si and SiGe can be epitaxially grown on the obtained Si substrate. Also polycrystal
Pre-growth treatment of Si, WSi, MoSi, W, Al, Mo, TiN, etc. can also be performed at a temperature lower than the evaporation temperature of the native oxide film.

[0006]

EXAMPLE 1 FIG. 1 is a sectional view of an apparatus for carrying out the method of the present invention. NH
Washed with a 1: 1: 5 mixture of ₄ OH: H ₂ O ₂ : H ₂ O (100) n /
The n ⁺ Si substrate 2 was placed in the reaction chamber 1 and

[0007]

[Table 1]

Only one pulse of ultraviolet rays was irradiated by a KrF excimer laser under the conditions shown in. Immediately after that, Table 2

[0009]

[Table 2]

A SiGe film was grown to 1000 Å under the conditions shown in.
This film was an epitaxial film. The change in the n / n ⁺ interface of the Si substrate due to laser irradiation was below the resolution of secondary ion mass spectrometry.

Comparative Example 1 The SiGe film grown in the same manner as in Example 1 except that the laser irradiation shown in Table 1 was not performed was a polycrystalline film.

Comparative Example 2 Instead of the laser irradiation shown in Table 1, the substrate was heated to 1000 with an infrared lamp.
The SiGe film grown in the same manner as in Example 1 except that it was heated to 0 ° C. for 10 minutes was an epitaxial film, but as a result of secondary ion mass spectrum analysis, the n / n ⁺ interface was diffused.

[0013]

According to the present invention, the natural oxide film can be removed by heating only the surface of the Si substrate, and the semiconductor characteristics are not deteriorated by heating the inside of the Si substrate.

[Brief description of drawings]

1 is a cross-sectional view of an apparatus for carrying out the method of the present invention.

[Explanation of symbols]

1 ... Reactor 2 ... Si substrate 3 ... KrF excimer laser 4 ... Laser beam expander 5 ... Quartz window 6 ... Infrared lamp 7 ... Pyrometer

Claims (3)

[Claims] 1. A method of manufacturing a semiconductor device, which comprises a step of irradiating a Si substrate with ultraviolet rays that can be turned on and off in an extremely short time of 1 second or less to remove a natural oxide film on the Si substrate. 2. The method according to claim 1, wherein the ultraviolet ray is irradiated by an excimer laser. 3. The method according to claim 1, wherein the epitaxial crystal film is grown after removing the native oxide film.