Stable ZnO thin film transistors by fast open air atomic layer deposition

We report stable, high performance zinc oxide thin film transistors grown by an atmospheric pressure atomic layer deposition system. With all deposition and processing steps kept at or below 200°C, the alumina gate dielectric shows low leakage (below 10−8A∕cm2) and high breakdown fields. Zinc oxide thin film transistors in a bottom gate geometry yield on/off ratios above 108, near zero turn-on voltage, little or no hysteresis, and mobility greater than 10cm2∕Vs. With alumina passivation, shifts in threshold voltage under gate bias stress compare favorably to those reported in the literature.