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 cm²/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/SiO₂ interface decrease to 2.16×10¹⁷ cm^-3eV^-1 and 4.38×10¹² 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.