FORMATION OF SEMICONDUCTOR THIN FILM

PURPOSE: To provide a forming method of a semiconductor thin film wherein step coverage is excellent, fine contact holes are easily formed, and contact resistance is small. CONSTITUTION: A silicon oxide film 13 is formed on a silicon substrate 11, and an n diffusion layer 12 is formed on the silicon substrate 11. Fine contact holes 14 are bored in the silicon oxide film 13, and the n diffusion layer is exposed. While impurities are introduced, a thin film 15 of amorphous silicon germanium (a-Si1-x Gex ) is deposited by a CVD method, in the manner in which the Ge content of a polycrystalline Si1-x Gex thin film becomes optimum, e.g. x=0.2-0.4. After that, the thin film 15 is polycrystallized by heat treatment, and a polycrystalline SiGe thin film 16 is formed.