Patent ID: 9012905
Filing Date: 2015-04-21
Classification: H01L

Abstract:
1. A semiconductor device comprising a transistor, the transistor comprising: a base insulating film comprising a first oxide insulating layer and a second oxide insulating layer surrounding the first oxide insulating layer, a surface of the base insulating film including a boundary between the first oxide insulating layer and the second oxide insulating layer; an oxide semiconductor film on the surface of the base insulating film; a gate insulating film over the oxide semiconductor film; a gate electrode overlapping with the oxide semiconductor film with the gate insulating film interposed therebetween; and a pair of electrodes over the oxide semiconductor film, wherein an end portion of the oxide semiconductor film which crosses a channel width direction of the transistor extends beyond the boundary between the first oxide insulating layer and the second oxide insulating layer toward the second oxide insulating layer.