Impact of tandem IGZO/ZnON TFT with energy-band aligned structure

Thin film transistors with high mobility and bias stability were fabricated using an In–Ga–Zn–O (IGZO)/zinc oxynitride (ZnON) tandem structure. In addition to increasing the saturation mobility from 13.44 cm2/V s to 24.75 cm2/V s, the hysteresis and device degradation under positive bias stress decreased more than five times as the ZnON semiconductor was added to the IGZO layer. These results were due to the reduced number of trapped electrons caused by the lower amount of relatively deep trap sites in the ZnON semiconductor and the existence of an energy barrier between ZnON and IGZO layers.