Effect of Al2O3 Passivation Layer and Cu Electrodes on High Mobility of Amorphous IZO TFT

In this paper, we present a high mobility amorphous indium-zinc-oxide (a-IZO) thin film transistor (TFT) based on copper (Cu) source/drain electrodes (S/D) and aluminum oxide (Al2O3) passivation layer (PVL). The mechanism of high mobility for the a-IZO TFT based on Cu S/D with Al2O3 PVL was proposed and experimentally demonstrated. The sputtering of Al2O3 PVL induced a highly conductive channel layer due to the formation of In-rich layer on the back channel. Also, Cu S/D presented Schottky contact behavior compared with Mo S/D which behaved like Ohmic contact. Because the Schottky contact can block leakage current and the highly conductive channel achieved high on-current, the a-IZO TFT based on Cu S/D and Al2O3 PVL performed remarkable saturation mobility up to 412.7 cm(2)/Vs. This paper presents a feasible way to implement high mobility TFT arrays with Cu electrodes.