A kind of low-temperature epitaxy preparation method of germanium-silicon thin film with high germanium content

Abstract

The invention discloses a low-temperature epitaxy preparation method of a germanium-silicon film with high germanium content. The low-temperature epitaxy preparation method comprises the following specific steps: (1) providing a silicon substrate with a (100) crystal face; (2) carrying out deoxidation on the silicon substrate at the temperature of 1350 DEG C, wherein the deoxidation lasts for 10 minutes; (3) through a molecular beam epitaxy method, growing a silicon buffer layer with the thickness of 20 to 50 nm on the silicon substrate after deoxidation, wherein the growth temperature is 700 DEG C; and (4) cooling the silicon buffer layer to a growth temperature which is below 300 DEG C, then growing GexSi1-x alloy, and adjusting the content of Ge, namely an x value, by changing the growth rates of Ge and Si. According to the preparation method, the high-quality germanium-silicon (GexSi1-x) film material with adjustable lattice constants can be directly grown on the silicon wafer at low temperature, and the content of germanium at most can reach 83%. The method does not need to adopt a layer-by-layer growth pattern for improving the content of germanium layer by layer, so that the method is simpler in operation and lower in cost.

Description

technical field [0001] The present invention relates to a method for directly growing germanium-silicon alloy thin films on silicon wafers, more specifically, it relates to the optimization of growth conditions for direct epitaxial germanium-silicon thin films with high germanium content (germanium content greater than 50%) on silicon wafers, Including the treatment of the substrate, the growth of the buffer layer and the optimization process of the growth temperature of the silicon-germanium alloy. Background technique [0002] Silicon (Si) and germanium (Ge) are the most common semiconductor materials and are also important materials for electronic components. Germanium-silicon alloy with adjustable band gap, adopting standard CMOS technology, can obtain ideal electronic control performance, and has important application value. However, since the lattice mismatch between germanium and silicon is above 4%, it is difficult to obtain high-quality germanium-silicon epitaxial ...

AI Technical Summary

Problems solved by technology

This method is complicated to operate and needs to constantly change the ratio of germanium to silicon, which is a waste of time and high cost

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