Patent ID: 9570594
Date: 2017-02-14
CPC Classifications: H01L

Claim:
1. A semiconductor device comprising: a first oxide film; a second oxide film over the first oxide film, the second oxide film comprises indium, gallium, and zinc; a source electrode layer; a drain electrode layer; a first gate insulating film in contact with the source electrode layer and the drain electrode layer; and a first gate electrode layer over the second oxide film with the first gate insulating film therebetween, wherein the first gate electrode layer is located in a depressed portion between the source electrode layer and the drain electrode layer, wherein the second oxide film does not overlap with the source electrode layer and the drain electrode layer, wherein the first gate electrode layer does not overlap with the source electrode layer and the drain electrode layer, wherein a side surface of the second oxide film is in contact with the source electrode layer, wherein an opposite side surface of the second oxide film is in contact with the drain electrode layer, wherein a thickness of the source electrode layer is larger than a thickness of the second oxide film, and wherein a thickness of the drain electrode layer is larger than the thickness of the second oxide film.