Effects of various oxygen partial pressures on Ti-doped ZnO thin film transistors fabricated on flexible plastic substrate

By applying a novel active layer of titanium zinc oxide (TiZO), we have successfully fabricated fully transparent thin-film transistors (TFTs) with a bottom gate structure fabricated on a flexible plastic substrate at low temperatures. The effects of various oxygen partial pressures during channel deposition were studied to improve the device performance. We found that the oxygen partial pressure during channel deposition has a significant impact on the performance of TiZO TFTs, and that the TFT developed under 10% oxygen partial pressure exhibits superior performance with a low threshold voltage (Vth) of 2.37V, a high saturation mobility (μsat) of 125.4cm2V-1 s-1, a steep subthreshold swing (SS) of 195mV/decade and a high Ion/Ioff ratio of 3.05 _ 108. These results suggest that TiZO thin films are promising for high-performance fully transparent flexible TFTs and displays. © 2016 The Japan Society of Applied Physics.