The influence of NH3 plasma treatment on Al2O3/HfO2 gate dielectrics of TFTs with atmospheric pressure plasma jet deposited IGZO channel

Abstract

Indium-gallium-zinc-oxide (IGZO) thin-film transistors are fabricated by atmospheric pressure plasma jet (APPJ) technique. HfO₂ (25 nm) and Al₂O₃ (25 nm) are used as the gate dielectric stack. NH₃ plasma treatment is applied to optimize the device performance by reducing the gate dielectric leakage and increasing the oxide capacitance. The best performance of the APPJ IGZO TFT is obtained with a 30W-60s NH₃ plasma treatment with field-effect mobility of 6.1 cm²/V-s, subthreshold swing of 0.19 V/dec, and on/off current ratio of 10⁸.