Patent ID: 9166055
Filing Date: 2015-10-20
Classification: H01L

Abstract:
1. A semiconductor device comprising: an oxide semiconductor stack comprising a first oxide semiconductor layer and a second oxide semiconductor layer; a source electrode layer and a drain electrode layer over the oxide semiconductor stack; an insulating film over the oxide semiconductor stack; and a gate electrode layer over the insulating film, the gate electrode layer overlapping with the oxide semiconductor stack, wherein energy gaps of the first oxide semiconductor layer and the second oxide semiconductor layer are different from each other, wherein the oxide semiconductor stack includes a first region, a second region, a third region, a fourth region, and a fifth region, wherein the gate electrode layer overlaps the first region, wherein the source electrode layer is in contact with the second region, wherein the drain electrode layer is in contact with the third region, wherein the fourth region and the fifth region are not overlapped by any of the gate electrode layer, the source electrode layer, and the drain electrode layer, wherein an impurity concentration of the fourth region is higher than that of the second region, and wherein an impurity concentration of the fifth region is higher than that of the third region.