Enhancing IGZO Thin Film Transistor Scalability Through Tunneling Contact

By inserting a single layer of graphene in between the metal to In-Ga-Zn-O (IGZO) contact, the channel carrier injection mechanism of an IGZO Thin-Film-Transistor (TFT) can be converted from thermionic emission to tunneling. Experimental results show that the tunneling-TFT can be scaled to a small dimension without compromising leakage current. A 2μm tunneling-TFT shows early saturation and similar subthreshold slope as the long channel devices, while the conventional TFTs can hardly be switched off. Further reduction of the IGZO film thickness can better suppress the short channel effect of the TC-TFTs.