High performance self-aligned top-gate ZnO thin film transistors using sputtered Al ₂O ₃ gate dielectric

High performance self-aligned top-gate zinc oxide (ZnO) thin film transistors (TFTs) utilizing high-k Al ₂O ₃ thin film as gate dielectric are developed in this paper. Good quality Al ₂O ₃ thin film was deposited by reactive DC magnetron sputtering technique using aluminum target in a mixed argon and oxygen ambient at room temperature. The resulting transistor exhibits a field effect mobility of 27 cm ²/V s, a threshold voltage of - 0.5 V, a subthreshold swing of 0.12 V/decade and an on/off current ratio of 9 × 10 ⁶. The proposed top-gate ZnO TFTs in this paper can act as driving devices in the next generation flat panel displays.