Patent ID: 8039840

Claim:
A display device comprising: a thin film transistor comprising: a gate electrode formed of a first conductive film; a gate insulating film formed of a first insulating layer over the gate electrode; a first semiconductor layer over the first insulating layer, wherein the first semiconductor layer is overlapped with the gate electrode; a channel protective film which is formed of a second insulating layer over the first semiconductor layer, wherein the channel protective film is overlapped with the gate electrode; a second semiconductor layer having an impurity element imparting one conductivity type, wherein the second semiconductor layer is overlapped with the first semiconductor layer, wherein the second semiconductor layer is divided into a source region and a drain region, wherein one end portion of the source region and one end portion of the drain region is provided over the channel protective film; and a source electrode over the source region and a drain electrode over the drain region, wherein the source electrode and the drain electrode are formed of a second conductive film; a third insulating layer formed over the source electrode and the drain electrode; a pixel electrode formed of a third conductive film over the third insulating layer, wherein the pixel electrode is electrically connected to one of the source electrode and the drain electrode through a contact hole formed in the third insulating layer; a capacitor wiring formed of a stacked body which includes the first semiconductor layer, the second semiconductor layer, and the second conductive film over the first insulating layer; and a storage capacitor formed of a stacked body which includes the capacitor wiring, the third insulating layer, and the pixel electrode.