US Patent 10103277 Method for manufacturing oxide semiconductor film

A method comprising a step of forming an oxide semiconductor film over a substrate by a sputtering method while heating the substrate at a temperature of higher than 200° C. and lower than or equal to 400° C. is provided. The oxide semiconductor film comprises a crystalline region and is in a non-single-crystal state. The step of forming the oxide semiconductor film is performed by using a sputtering target comprising indium, gallium, zinc and oxygen and a sputtering gas comprising at least one of a rare gas and oxygen.