Gaas thin film grown on Si substrate and preparation method thereof

Abstract

The invention discloses a preparation method for a GaAs thin film grown on a Si substrate. The preparation method comprises the following steps of: (1) cleaning the Si substrate; (2) pre-processing the Si substrate; (3) deoxidizing the Si substrate; (4) growing a buffer layer, in which an In<x>Ga<1-x>P buffer layer of 2 to 20 nanometers is grown on the surface of the Si substrate processed through the step (3) at a growth temperature of 350-500 DEG C; and (5) growing the GaAs thin film, in which the GaAs thin film is grown on the In<x>Ga<1-x>P buffer layer at a growth temperature of 500-580 DEG C. The invention also discloses the GaAs thin film grown on the Si substrate. The preparation method has the advantages of simplicity in the structure of the buffer layer, convenience in an epitaxial growth process and the like, and the obtained GaAs epitaxial thin film is flat in surface, low in dislocation density and high in crystal quality.

Description

technical field [0001] The invention relates to a GaAs thin film and a preparation method thereof, in particular to a GaAs thin film grown on a Si substrate and a preparation method thereof. Background technique [0002] III-V compounds are widely used in optoelectronic devices due to their advantages of good stability, small effective mass, high electron mobility and peak velocity, and high light absorption coefficient. Among them, the band gap of GaAs is 1.42eV, which corresponds to the highest energy band in the solar spectrum, so it is very suitable for the production of solar cells and photodetectors. Commonly used substrate materials for growing GaAs semiconductor devices are GaAs or Ge, etc., but these materials are expensive, thus increasing the preparation cost of GaAs-based semiconductor materials. Compared with GaAs and Ge, Si has the advantages of mature technology, low price, and easy large-scale size. If epitaxial growth of high-quality GaAs materials can be r...

AI Technical Summary

Problems solved by technology

On the one hand, the lattice constant of Si is smaller than that of GaAs, and there is more than 4% lattice mismatch between them, which will cause a large number of misfit dislocations in GaAs during growth, deteriorating device performance

On the other hand, due to the surface characteristics of the Si substrate, defects such as twin crystals and reverse domains are also more likely to appear, especially when there is a large mismatch stress between the epitaxial material and the substrate.

The formation of these defects will cause a large number of pyramid-shaped or trench-shaped protrusions to form on the surface of the epitaxial film, which seriously affects the surface flatness of GaAs semiconductor devices.

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