Modulation of Interface and Bulk States in Amorphous InGaZnO Thin-Film Transistors with Double Stacked Channel Layers

A high-performance amorphous InGaZnO (a-IGZO) thin-film transistor (TFT) was achieved using a double stacked channel layer (DSCL). An oxygen-poor IGZO film was deposited in pure argon ambient as a buffer layer to prevent oxygen plasma bombardment and improve device performance. An oxygen-rich IGZO film was then deposited on top of that buffer layer to modulate device stability. With this structure, an interface with low oxygen-plasma-induced damage and few oxygen vacancies in the bulk was achieved using DSCL, leading to a higher stability of the threshold voltage. (C) 2013 The Japan Society of Applied Physics