Hydrogenated IGZO Thin-Film Transistors Using High-Pressure Hydrogen Annealing

Hydrogenation of thin-film indium–gallium–zincoxide (IGZO) is carried out by applying a high-pressure hydrogen annealing (HPHA) process under 5-atm pressure at different temperatures of 260∘ C, 270∘ C, and 280∘ C. The HPHA effectively increases the carrier concentration and the Hall mobility up to~10¹⁹~ cm⁻³and~6.4~ cm²/ Vs, respectively. The HPHA-IGZO films exhibit smoother surfaces as compared with the as-grown films. The HPHA performs at a temperature of 260∘ Cthat greatly enhances the electrical characteristics of IGZO TFTs, leading to a saturation field effect mobility of 7.4cm²/ Vs, a subthreshold slope of 0.37 V/decade, a threshold voltage of 2.2 V, and anI_ ON/I_ OFFof2.0× 10⁶.