Performance enhancement of In-Ga-Zn-O TFTs using double-layer gate dielectric

Abstract

We insert a low-temperature deposited (L-D) SiO2 between the high-temperature deposited (H-D) SiO2 and In-Ga-Zn-O (IGZO) active layer to enhance the TFT performance. Compared with the single SiO2 TFT, the performance of the double-layer SiO2 TFT shows obvious improvements, for instance, the saturation mobility (μsat) increases from 0.21 to 0.98 cm²/V•s, the subthreshold swing (SS) decreases from 1.05 to 0.506 V/decade and the Ion/Ioff increases from 8.2×10⁵ to 1.28×10⁶.