The effect of UV-assisted cleaning on the performance and stability of amorphous oxide semiconductor thin-film transistors under illumination

The effect of ultraviolet (UV) cleaning on the performance and stability of amorphous oxide transistors was evaluated. The application of UV cleaning at all process steps prior to the growth of the active layer induces relatively small threshold voltage (V_T) shifts upon negative bias illumination stress (NBIS). On the other hand, additional UV cleaning right after the active growth engenders significant device degradation upon NBIS, which is manifested by severe negative V_T shifts. It is suggested that the exposure of the oxide semiconductor to UV radiation is accompanied with the creation of defects that provide trapping sites for photogenerated holes.