SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor device including an oxide semiconductor with stable electric characteristics and high reliability, and to manufacture a highly reliable semiconductor device in a high yield.SOLUTION: In a top-gate staggered transistor including an oxide semiconductor film: a first gate insulating film in contact with the oxide semiconductor film is formed of a silicon oxide film by a plasma CVD method using a deposition gas containing silicon fluoride and oxygen; and a second gate insulating film laminated over the first gate insulating film is formed of a silicon oxide film by a plasma CVD method using a deposition gas containing silicon hydride and oxygen.