Patent ID: 8330166

Claim:
A thin-film semiconductor device for a display apparatus, comprising: a substrate; a gate electrode on said substrate; a gate insulating film on said gate electrode; a first channel layer including a polycrystalline semiconductor layer on said gate insulating film; a second channel layer including a non-crystalline semiconductor layer on said first channel layer, said second channel layer including a protrusion between first top surface end portions of said second channel layer, the protrusion of said second channel layer having first lateral surfaces that each extend between one of the first top surface end portions of said second channel layer and a top surface of the protrusion of said second channel layer; an insulation layer on the top surface of the protrusion of said second channel layer, said insulation layer having second lateral surfaces that each extend to one of second top surface end portions of said insulation layer; two contact layers, each on one of the second top surface end portions of said insulation layer, adjacent one of the second lateral surfaces of said insulation layer and one of the first lateral surfaces of the protrusion, and on one of the first top surface end portions of said second channel layer; a source electrode on one of said two contact layers; and a drain electrode on an other of said two contact layers, wherein said two contact layers are of a first conductivity type, and an upper portion of the protrusion of said second channel layer is of a second conductivity type opposite the first conductivity type.