A method for manufacturing a semiconductor device is provided. In the method, a silicon-containing gas is supplied to a substrate having a recess in a surface thereof at a predetermined film deposition temperature, thereby depositing a first silicon film in the recess. Chlorine and hydrogen are supplied to the substrate while maintaining the predetermined film deposition temperature, thereby etching the first silicon film deposited in the recess to expand an opening width of the first silicon film. The silicon-containing gas is supplied to the substrate while maintaining the predetermined film deposition temperature, thereby further depositing a second silicon film on the first silicon film in the recess.