High-Performance Indium-Gallium-Zinc-Oxide Thin-Film Transistors with Stacked Al₂O₃/HfO₂ Dielectrics

Abstract

High-performance amorphous indium-gallium-zinc-oxide thin-film transistors (a-IGZO TFTs) gated by Al 2 O 3 /HfO 2 stacked dielectric films are investigated. The optimized TFTs with Al 2 O 3 (2.0 nm)/HfO 2 (13 nm) stacked gate dielectrics demonstrate the best performance, including low total trap density N t , low subthreshold swing voltage, large switching ratio I ON/OFF , high mobility μ FE , and low operating voltage, equal to 1.35 × 10 12 cm −2 , 88 mV/dec, 5.24 × 10 8 , 14.2 cm 2 /V⋅s, and 2.0 V, respectively. Furthermore, a low-voltage-operated resistor-loaded inverter has been fabricated based on such an a-IGZO TFT, showing ideal full swing characteristics and high gain of ∼27 at 3.0 V. These results indicate a-IGZO TFTs gated by optimized Al 2 O 3 /HfO 2 stacked dielectrics are of great interests for low-power, high performance, and large-area display and emerging electronics.