Method for reducing defects in silicon carbide epitaxial film

Abstract

The invention discloses a method for reducing defects in a silicon carbide epitaxial film. The method is executed in horizontal hot wall-type chemical vapor deposition (CVD) equipment and comprises the following steps of 1) substrate preparing, wherein a (0001) silicon-surface silicon carbide substrate deviating towards the (11-20) direction by 4 degrees is selected; 2) pre-growth baking, wherein a reaction chamber is subjected to radio frequency induction heating after a prepared sample is delivered to a reaction chamber and before gas is injected; 3) in-situ etching, wherein an improved hydrogen H2 in-situ etching technology is employed to perform pre-growth surface pre-treatment of the substrate; and 4) epitaxial growing, wherein a silicon carbide film starts to grow when the temperature rises to an epitaxial growth temperature. The advantages are that by using the method, the defects existing in the epitaxial film based on the (0001) silicon-surface silicon carbide substrate deviating towards the (11-20) direction by 4 degrees can be effectively reduced and the quality of the epitaxial film can be increased. The characteristics are that the method of the invention is simple and easy to implement; the epitaxial technology repeatability and consistency are good; the epitaxial film quality is high; and the method is suitable for mass production.

Description

technical field [0001] The present invention relates to a method for reducing defects in a homoepitaxial thin film based on a (0001) silicon surface silicon carbide substrate with a 4° bias to the <11-20> direction. It belongs to the technical field of semiconductor materials. Background technique [0002] In recent years, silicon carbide (SiC) epitaxial materials and devices are growing steadily and rapidly, and in some fields it is gradually replacing traditional silicon and gallium arsenide materials. Silicon carbide has better material properties than silicon and gallium arsenide. For example 4H-SiC, which has approximately 4×10 6 V / cm breakdown field strength, about 2×10 7 cm / s electron drift velocity and about 4.9W / cm·K thermal conductivity, while having high chemical stability and radiation resistance. These excellent material properties make silicon carbide particularly suitable for high power, high temperature and high frequency applications. [0003] Mos...

AI Technical Summary

Problems solved by technology

However, there are a large number of defects such as step-like morphology and triangular defects in the epitaxial film grown on the 4° off-angle substrate, which is not conducive to the later device fabrication

Although there have been some reports on reducing defects in epitaxial films on (0001) silicon carbide substrates with a 4° bias to the direction, such as the use of low C / Si ratios and hydrogen in-line etching, etc., the elimination of defects The effect is not ideal, such as Figure 1 and Figure 2 shows that there are still a lot of steps in the epitaxial film Defects such as appearance

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