US Patent 8188480 Thin film field effect transistor and display

A TFT is provided which includes, 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 between the active layer and at least one of the source electrode or the drain electrode, and a band gap of the active layer is smaller than a band gap of the resistance layer. Also, a display using the TFT is provided.