Patent ID: 7998845

Claim:
A method of manufacturing a semiconductor device, comprising the steps of: forming a semiconductor film over an insulating surface, wherein the semiconductor film contains germanium and has an amorphous structure; adding a metal element for accelerating crystallization to the semiconductor film having the amorphous structure; performing a heat treatment to the semiconductor film having the amorphous structure to form a semiconductor film having a crystalline structure; irradiating the semiconductor film having the crystalline structure with a first laser light in an atmosphere or in an oxygen atmosphere; irradiating the semiconductor film having the crystalline structure with a second laser light in an inert gas atmosphere or in a vacuum, after irradiating with the first laser light, forming a second semiconductor film including a rare gas element over the semiconductor film having the crystalline structure, after irradiating with the second laser light; gettering the metal element from the semiconductor film having the crystalline structure into the second semiconductor film; and removing the second semiconductor film.