High performance ZnO-based thin film transistor with high-κ gate dielectrics fabricated at low temperature

D.D. Han, J. Cai, W. Wang, L.L. Wang, Y.C. Ren, S.J. Li, Y. Wang, S.D. Zhang
Peking University, CN

Keywords: ZnO-based thin film transistor, high-κ gate dielectrics, low temperature

Summary:

We report on the fabrication and characteristics of low-driven-voltage and high mobility the thin film transistors (TFTs) using ZnO as an active channel layer grown by using radio frequency (rf) magnetron sputtering technique. The TFT device structure used in this study is a bottom gate type, which consists of high-κ HfO2 film as the gate dielectric. The sputtering and post-annealing conditions of the gate insulators are optimized for leakage current and TFT performances. The device shows a low threshold voltage of 1 V, an high on/off ratio of 1.0×107, a high field effect mobility of 32.1 cm2 / V · s, a subthreshold swing of 0.46 V/decade, and the off current of less than 10-12A at a maximum device processing temperature of 280℃. The ZnO-TFT is a very promising low-cost optoelectronic device for the next generation of invisible and flexible electronics due to transparency, high mobility, and low-temperature processing.