To make it the growth of a facet on the interface between a single crystal silicon film and a silicon oxide film hard to generate by a method wherein a semiconductor device is formed into a constitution, wherein an epitaxial layer is grown on the surface which is exposed in an open part formed in the silicon oxide film of a semiconductor substrate by a selective and epitaxial growth method.

The exposed surface of a silicon substrate 11 is cleaned by a proper method, and thereafter a selective and epitaxial growth is performed in an open part 13 and an epitaxial layer 22 is formed in the open part 13. The representative condition of this selective and epitaxial growth is a condition that a temperature is set at 800°C, a pressure is set at 6.7×102 Pa, dichlorosilane (SiH2Cl2) gas is flowed at a flow rate of 100 SCCM as reaction gas and HCl gas and H2 gas are respectively flowed at a flow rate of 10 SCCM and a flow rate of 1,000 SCCM as carrier gas. As this result, there is not a facet on the interface between the sidewall of a silicon oxide film 12 and the epitaxially grown film 22 and a selectively and epitaxially grown layer having not a defect can be formed.