Patent ID: 8680528

Claim:
A display device comprising: a gate electrode over a substrate; a first insulating film over the gate electrode; a microcrystalline semiconductor film including a channel formation region, the microcrystalline semiconductor film over the gate electrode with the first insulating film interposed therebetween; an amorphous semiconductor film over and being in contact with the microcrystalline semiconductor film; a pair of semiconductor films comprising an impurity element imparting one conductivity type, the pair of semiconductor films over the microcrystalline semiconductor film; and a second insulating film over the microcrystalline semiconductor film, the amorphous semiconductor film, and the pair of semiconductor films, wherein end portions of the microcrystalline semiconductor film are positioned more inwardly than end portions of the gate electrode, and wherein the amorphous semiconductor film contains nitrogen, carbon, and oxygen at a total concentration of greater than or equal to 1×10 20 atoms/cm 3 and less than or equal to 15×10 20 atoms/cm 3 .