Patent ID: 9660095
Date: 2017-05-23
CPC Classifications: H01L

Claim:
1. A semiconductor device comprising: an insulating film; and a semiconductor film over the insulating film, wherein the semiconductor film comprises an oxide semiconductor, wherein the insulating film includes a portion with a curved surface, wherein the semiconductor film comprises a curved portion including a first curved surface and a second curved surface, wherein the first curved surface of the curved portion of the semiconductor film is in contact with the curved surface of the portion of the insulating film, wherein a curvature radius of the first curved surface of the curved portion of the semiconductor film is longer than or equal to 20 nm and shorter than or equal to 60 nm, wherein the first curved surface of the curved portion of the semiconductor film is located inside the curved surface of the portion of the insulating film, wherein the curved portion of the semiconductor film comprises a channel formation region, wherein the first curved surface and the second curved surface of the curved portion of the semiconductor film are opposite to each other, wherein the channel formation region is located between the first curved surface and the second curved surface of the curved portion of the semiconductor film, and wherein the semiconductor film has a crystalline region including crystals whose c-axes are substantially parallel to a normal vector of the curved surface of the portion of the insulating film.