Effects of Electrical Bias Stress on the Performance of ZnO-Based TFTs Fabricated by RF Magnetron Sputtering

-based thin film transistors (TFTs) were fabricated on a tin oxide (ITO)/glass substrate by radio frequency (rf) magnetron sputtering at . The transfer characteristics of the fabricated TFT showed a drain current on/off ratio of , a field effect mobility of , an off current lower than , and a threshold voltage of . The stability of the TFTs was examined under various electrical bias stress conditions. The operation of TFT was stable at the electrical bias stress ( at , ) for stress time of . However, with increasing bias stress and the duration of the stress, the transfer characteristics of TFT were degraded, and the devices were physically damaged due to heavy charge accumulation in the channel layer. In addition, trapping of tunneling electrons in the caused threshold voltage shift.