US Patent 9269821 Semiconductor device

A transistor including an oxide semiconductor layer can have stable electrical characteristics. In addition, a highly reliable semiconductor device including the transistor is provided. A semiconductor device includes a multi-layer film including an oxide layer and an oxide semiconductor layer, a gate insulating film in contact with the multi-layer film, and a gate electrode overlapping with the multi-layer film with the gate insulating film provided therebetween. In the semiconductor device, the oxide semiconductor layer contains indium, the oxide semiconductor layer is in contact with the oxide layer, and the oxide layer contains indium and has a larger energy gap than the oxide semiconductor layer.