Preparation and effects of O2 flow on the electrical characteristics of Li doped MgZnO thin film transistors

Abstract

In this paper, the authors attempt to fabricate thin film transistors using Li doped MgZnO (MgZnO:Li) as the active layer. The MgZnO:Li films were deposited by the radio frequency magnetron sputtering technique at room temperature. As the ideal active layer thickness is controlled at 35 nm, the mechanism on the electrical characteristic transition induced by Ar/O2 mixed plasma treatment was discussed. The results confirm that the appropriate sputtering Ar/O2 gas flow ratio (30/3) could compensate for the intrinsic defects in the channel, which is beneficial to MgZnO:Li thin film transistors. In addition, the fabricated device exhibited the best performance with a saturation mobility of 12.9 cm2/V s, a threshold voltage of −15 V, and a large on/off current ratio of 2.5 × 107.