Patent ID: 8188480

Claim:
A thin film field effect transistor comprising, on a substrate, at least a gate electrode, a gate insulating layer, an active layer containing an amorphous oxide semiconductor, a source electrode and a drain electrode, wherein a resistance layer containing an amorphous oxide and having a thickness of more than 3 nm is disposed to cover an entire surface of the active layer at a side at which the source electrode and the drain electrode are provided, and is disposed between the active layer and at least one of the source electrode or the drain electrode, a band gap of the active layer is smaller than a band gap of the resistance layer, the active layer does not directly contact the drain electrode and the source electrode, and the band gap of the active layer is 2.0 eV or more and less than 4.0 eV, and wherein the resistance layer further covers the entire side surfaces of the active layer.