According to one embodiment, a method for forming a semiconductor device includes: forming a first underlayer film that contains a first atom selected from the group consisting of germanium, aluminum, tungsten, hafnium, titanium, tantalum, nickel, cobalt and alkaline earth metals; forming, on the first underlayer film, a second underlayer film that contains a second atom selected from the group consisting of germanium, aluminum, tungsten, hafnium, titanium, tantalum, nickel, cobalt and alkaline earth metals, the second atom being an atom not contained in the first underlayer film; and forming, on the second underlayer film, a silicon oxide film by a CVD or ALD method by use of a silicon source containing at least one of an ethoxy group, a halogen group, an alkyl group, and an amino group, or a silicon source of a siloxane system.