Patent ID: 9184245
Filing Date: 2015-11-10
Classification: H01L

Abstract:
1. A semiconductor device comprising: a first oxide insulating layer over a semiconductor substrate; a first oxide semiconductor layer over the first oxide insulating layer; a second oxide semiconductor layer over the first oxide semiconductor layer; a third oxide semiconductor layer over the second oxide semiconductor layer; a second oxide insulating layer over the third oxide semiconductor layer; and a first gate electrode layer overlapping with at least the second oxide semiconductor layer with the second oxide insulating layer provided therebetween, wherein the first oxide semiconductor layer, the second oxide semiconductor layer, and the third oxide semiconductor layer each comprise indium, wherein a proportion of indium in the second oxide semiconductor layer is higher than a proportion of indium in each of the first oxide semiconductor layer and the third oxide semiconductor layer, wherein the second oxide semiconductor layer has a crystalline structure, wherein the third oxide semiconductor layer and a side surface of the second oxide semiconductor layer are in contact with each other, wherein the third oxide semiconductor layer and the first oxide semiconductor layer are in contact with each other, and wherein the third oxide semiconductor layer and the first oxide insulating layer are in direct contact with each other.