Enhanced stability against bias-stress of metal-oxide thin film transistors deposited at elevated temperatures

Transparent zinc-tin-oxide (ZTO) thin film transistors (TFTs) have been prepared by DC magnetron sputtering. Compared to reference devices with a channel deposited at room temperature and subsequently annealing at 400 degrees C, a substantially enhanced stability against bias stress is evidenced for devices with in-situ substrate heating during deposition (400 degrees C). A reduced density of sub-gap defect states in TFT channels prepared with in-situ substrate heating is found. Concomitantly, a reduced sensitivity to the adsorption of ambient gases is evidenced for the in-situ heated devices. This finding is of particular importance for an application as driver electronics for organic light emitting diode displays. (C) 2011 American Institute of Physics. [doi:10.1063/1.3643040]