In-situ fluorine-doped ZnSnO thin film and thin-film transistor

Abstract

In this paper, in-situ fluorine-doped ZnSnO (ZTO:F) thin films prepared by co-sputtering are proposed. It was found that the F had been successfully introduced into the ZTO thin films and distributed uniformly in the bulk. The corresponding top-contact bottom-gated ZTO:F thin film transistors (TFTs) were fabricated with an annealing temperature of 350 °C. The fabricated TFTs exhibit a field-effect mobility of 14.2 cm2V−1s−1, on-off ratio of over 109, and subthreshold swing (SS) as low as 87 mV/decade due to the incorporation of F. In addition, the bias stability of fabricated TFTs was also examined and the Vth shifts under negative gate bias stress are not more than ±0.1 V even without any passivation. It is expected that the In-free ZTO:F amorphous oxide semiconductor and the corresponding TFTs have potential for low-cost and environmentally safe fabrication.