Patent ID: 8394726

Claim:
A method for manufacturing a semiconductor device, comprising the steps of: loading a substrate into a reaction chamber; supplying reactive gases into the reaction chamber and processing the substrate; and unloading the processed substrate from the reaction chamber, wherein the step of processing the substrate includes the following sequential steps: (i) a first film formation step of setting the substrate to a first temperature and forming a first silicon film on the substrate by using a first reactive gas with a first film-forming reactive compound, the first silicon film including impurity atoms, (ii) raising the temperature of the substrate to an interim temperature above the first temperature, and (iii) a second film formation step of setting the substrate to a second temperature, which is lower than the first temperature and is lower than a thermal decomposition temperature of the first reactive gas, and forming a second silicon film on at least the first silicon film using a second reactive gas that has a second film-forming reactive compound different from the first film-forming reactive compound, the second silicon film including no impurity atoms or having an impurity concentration lower than that of the first silicon film.