Patent ID: 8067775
Filing Date: 2011-11-29
Classification: H01L

Abstract:
1. A semiconductor device comprising: a pixel portion; and a driver circuit, wherein the pixel portion includes at least a first thin film transistor including a first oxide semiconductor layer, wherein the driver circuit includes at least a second thin film transistor including a second oxide semiconductor layer and a third thin film transistor including a third oxide semiconductor layer, wherein the third thin film transistor includes a first gate electrode below the third oxide semiconductor layer and a second gate electrode above the third oxide semiconductor layer, wherein the third oxide semiconductor layer includes a first region and a second region, wherein the second region overlaps with a source or a drain electrode of the third thin film transistor, wherein a thickness of the first region is smaller than a thickness of the second region, and wherein the second thin film transistor is one of an enhancement type transistor and a depletion type transistor and the third thin film transistor is the other of the enhancement type transistor and the depletion type transistor.