Patent ID: 7977750

Claim:
A semiconductor device comprising: at least a first n-channel thin film transistor being formed in a display region over a substrate; at least a second n-channel thin film transistor and at least a p-channel thin film transistor in a drive circuit each being formed in a periphery of the display region over the substrate; and a capacitor forming electrode formed adjacent to a portion of a crystalline semiconductor film to form a capacitor therebetween; the first n-channel thin film transistor includes: a gate electrode formed over the substrate, a first insulating film formed over the gate electrode, a second insulating film comprising silicon oxide formed over the first insulating film, the crystalline semiconductor film formed over the second insulating film, wherein the first n-channel thin film transistor has first and second channel regions, and source and drain regions, and wherein a channel length of the p-channel thin film transistor is shorter than that of the second n-channel thin film transistor.