Effect of Annealing on Defect Elimination for High Mobility Amorphous Indium-Zinc-Tin-Oxide Thin-Film Transistor

This letter studies the correlation of postannealing treatment on the electrical performance of amorphous In-Zn-Sn-O thin-film transistor (a-IZTO TFT). The 400 °C annealed a-IZTO TFT exhibits a superior performance with field-effect mobility of 39.6 cm 2 /Vs, threshold voltage (Vth) of -2.8 V, and subthreshold swing of 0.25 V/decade. Owing to the structural relaxation by 400 °C annealing, both trap states of a-IZTO film and the interface trap states at the a-IZTO/SiO 2 interface decrease to 2.16×10 17 cm -3 eV -1 and 4.38×10 12 cm -2 eV -1 , respectively. The positive bias stability of 400 °C annealed a-IZTO TFTs is also effectively improved with a V th shift of 0.92 V.