There is provided a technique that includes (a) pre-etching a surface of a substrate made of single crystal silicon by supplying a first etching gas to the substrate; (b) forming a silicon film on the substrate with the pre-etched surface, by supplying a first silicon-containing gas to the substrate; (c) etching a portion of the silicon film by supplying a second etching gas, which has a different molecular structure from a molecular structure of the first etching gas, to the substrate; and (d) forming an additional silicon film on the etched silicon film by supplying a second silicon-containing gas to the substrate.