Patent ID: 9171867
Filing Date: 2015-10-27
Classification: H01L

Abstract:
1. A semiconductor device comprising: a first conductive layer; a first insulating layer over the first conductive layer; an oxide semiconductor layer over the first insulating layer; a second insulating layer over the oxide semiconductor layer; a second conductive layer over the second insulating layer; a third conductive layer electrically connected to the oxide semiconductor layer; and a fourth conductive layer electrically connected to the oxide semiconductor layer, wherein the first conductive layer comprises a region functioning as a first gate electrode of a transistor, wherein the second conductive layer comprises a region functioning as a second gate electrode of the transistor, wherein the third conductive layer comprises a region functioning as one of a source electrode and a drain electrode of the transistor, wherein the fourth conductive layer comprises a region functioning as the other of the source electrode and the drain electrode of the transistor, wherein the first conductive layer comprises a region in which a second layer is stacked over a first layer, and wherein the first layer comprises a plateau extending beyond an end portion of the second layer.