Abstract: A thin film transistor (TFT) and the method of forming the same is provided. The method of forming the TFT on a surface of a substrate, includes the steps of: forming a gate electrode; deposing a gate dielectric on the gate electrode; forming a nanocrystalline silicon (nc-Si) layer and an amorphous silicon (a-Si:H) layer above the gate dielectric, so that the thickness of the nc-Si layer is less than 30 nm thereby reducing off-current; and forming a source/drain electrode. The TFT includes: a gate electrode on a substrate, a gate dielectric on the gate electrode; a nc-Si layer having a thickness less than 30 nm, thereby reducing off-current; an a-Si:H layer; and a source/drain electrode.