Low Voltage Driven, Stable Solution-Processed Zinc-Tin-Oxide TFT with HfOy and AlOx Stack Gate Dielectric

We report on low voltage driven, solution processed zinc-tin oxide (ZTO) transistors with a spin-coated hafnium oxide (HfOy) and aluminum oxide (AlOx) stack gate insulator (HfOy/AlOx). The ZTO TFT with a HfOy/AlOx dielectric processed at the maximum temperature of 400°C exhibits the field-effect mobility of 3.84 cm2/V s, subthreshold swing of 117 mV/dec., and threshold voltage (Vth) of 0.84 V. The positive gate bias stress degradation of Vth with time follows a stretched exponential behavior with a time constant of 1.13 × 107 s, indicating stable TFT.