Patent ID: 9281409
Filing Date: 2016-03-08
CPC Classification: H01L

Claim Text:
1. A semiconductor device comprising: a first oxide semiconductor film over an insulating surface; a second oxide semiconductor film over the first oxide semiconductor film; a third oxide semiconductor film in contact with a top surface of the insulating surface, a side surface of the first oxide semiconductor film, a side surface of the second oxide semiconductor film, and a top surface of the second oxide semiconductor film; a gate insulating film over the third oxide semiconductor film; and a gate electrode which is in contact with the gate insulating film and faces the top surface and the side surface of the second oxide semiconductor film, wherein a thickness of the first oxide semiconductor film is larger than a sum of a thickness of the third oxide semiconductor film and a thickness of the gate insulating film, and wherein a difference between the thickness of the first oxide semiconductor film and the sum of the thickness of the third oxide semiconductor film and the thickness of the gate insulating film is larger than or equal to 20 nm.