A technique of reducing fluctuation between elements is provided in which a semiconductor film having a crystal structure is obtained by using a metal element that accelerates crystallization of a semiconductor film and then the metal element remaining in the film is removed effectively. A barrier layer is formed on a semiconductor film having a crystal structure by plasma CVD from monosilane and nitrous oxide as material gas. In a step of forming a gettering site, a semiconductor film having an amorphous structure and containing a high concentration of noble gas element, specifically, 1.times.10.sup.20 to 1.times.10.sup.21/cm.sup.3, is formed by plasma CVD. The film is typically an amorphous silicon film. Then gettering is conducted.