Investigation of LaAlO3/ZrO2/a-InGaZnO thin-film transistors using atmospheric pressure plasma jet

Amorphous indium-gallium-zinc-oxide thin-film transistors (a-IGZO-TFTs) with the LaAlO₃/ZrO₂ gate dielectric stack employing a novel atmospheric pressure plasma jet process that results in small subthreshold swing and low threshold voltage are proposed and fabricated. The influence of post-deposition annealing (PDA) temperature on LaAlO₃/ZrO₂ gate dielectric stack and device performance was investigated. The equivalent oxide thickness of the LaAlO₃/ZrO₂ dielectric stack decreases from 11.5 nm without annealing to 7 nm after a 500°C annealing was applied. The LaAlO₃/ZrO₂/a-InGaZnO TFT with a 500°C annealing exhibits a small subthreshold swing of 77 mV·dec^-1, a high field-effect mobility of 9 cm²·V^-1·s^-1 and an excellent current ratio of 1.8 × 10⁷, which could be attributed to the improved gate dielectric quality by the PDA. The LaAlO₃/ZrO₂/a-InGaZnO TFTs with excellent gate control ability allow the device to operate at a low operating voltage with low power consumption.