Method for forming a thin film at low temperature by using
plasma pulses is disclosed. While a purge gas or a reactant purge gas activated by
plasma is continuously supplied into a reactor, a source gas is supplied intermittently into the reactor during which period
plasma is generated in the reactor so that the source gas and the purge gas activated by plasma reacts, so that a thin film is formed according to the method. Also, a method for forming a
thin layer of film containing a plural of metallic elements, a method for forming a thin metallic film containing varied contents by amount of the metallic elements by using a supercycle Tsupercycle comprising a combination of simple
gas supply cycles Tcycle, . . . , and a method for forming a thin film containing continuously varying compositions of the constituent elements by using a supercycle Tsupercycle comprising a combination of simple
gas supply cycles Tcycle, . . . , are disclosed. The methods for forming thin films disclosed here allows to shorten the purge cycle duration even if the reactivity between the source gases is high, to reduce the contaminants caused by the gas remaining in the reactor, to form a thin film at low temperature even if the reactivity between the source gases is low, and also to increase the rate of thin film formation.