ZnON contacts enabling high-performance 3-D InGaZnO inverters

The inclusion of an ultra-thin zinc oxynitride (ZnON) layer inserted between the channel of InGaZnO (IGZO) and source/drain (S/D) metal of Al for an IGZO thin-film transistor (TFT) is demonstrated to improve device performance in terms of a reduction in S/D series resistance (RSD). The improvement is attributable to the elimination of an interfacial layer of AlOx which is inherently formed at the Al/IGZO interface, by the insertion of ZnON. Characteristics of 3D stacked-type inverters constructed by the IGZO TFTs with ZnON contacts have been also studied. Full-swing switching with voltage gains increases from 9.8V/V for the IGZO inverter without ZnON contacts to 12.3 V/V with ZnON contacts at an operating voltage of 5 V.