Investigation of LaAlO 3 /ZrO 2 / a ‐InGaZnO thin‐film transistors using atmospheric pressure plasma jet

Abstract

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.