Effects of Post-Deposition Thermal Annealing Temperature on Electrical Properties of ZnON Thin-Film Transistors

We investigate the effects of the post-deposition thermal annealing temperature on the physical and chemical structure of zinc oxynitride (ZnON) thin films and on the electrical performance of ZnON thin-film transistors (TFTs). When a ZnON TFT is annealed at 150 °C, it exhibits conductive behavior, which is attributed to the increased electron concentration caused by the increase in the nitrogen vacancies of the defective ZnXNY bonds within the ZnON. The TFT shows the best electrical performance when the annealing temperature is 250 °C, but a degradation in the electrical performance is observed when the annealing temperature is increased to 350 °C. The significantly reduced electron concentration and the relative increase in the oxygen within the ZnON are considered as the possible reasons for the degradation in the electrical performance observed in the ZnON TFTs annealed at 350 °C.