Ultra-violet light enhanced super critical fluid treatment in In-Ga-Zn-O thin film transistor

A low-temperature ultra-violet (UV) light enhanced supercritical CO2 (SCCO2) fluid treatment is employed to improve the performance of In-Ga-Zn-O (IGZO) thin film transistor (TFT) device. In this study, amorphous IGZO film deposited by sputtering is investigated in SCCO2 ambient under different illumination conditions. After SCCO2 treatment with UV exposure, the mobility and subthreshold swing of the TFT can be significantly improved. A model is proposed to explain the mechanism, and the improvement is due to the reduction of dangling bonds at the grain boundary. With the help of UV, dangling bonds can be effectively passivated by OH chemical groups.