Light-Illumination-Induced Degradation in Elevated-Metal Metal-Oxide Thin-Film Transistors without and with Fluorination

Light-illumination-induced degradation in elevated-metal metal-oxide (EMMO) thin-film transistors without and with fluorination (F) is characterized and studied. EMMO TFTs shows little degradation under red light illumination stress (LIS) and shows a positive shift of the transfer curve under green and blue LISes. Positive charge generation and metastable defect state generation may be responsible for the LIS-induced degradation. Compared to EMMO TFTs without F, EMMO TFTs with F exhibit better reliability under LIS due to the reduction of oxygen vacancies by the formation of fluorine-metal bonds. The saturation behaviors and recovery behaviors may be due to the an immediate reduction of the donor-like states after the removal of LIS.