Effect of thermal annealing on the electrical characteristics of an amorphous ITZO:Li thin film transistor fabricated using the magnetron sputtering method

Abstract In this work, the effect of thermal annealing on the optimal and electrical characteristics of the ITZO:Li thin film transistor was investigated. The ITZO:Li active channel layer was deposited on an SiO 2 /p + +Si substrate by radio frequency magnetron sputtering at room temperature. The micro structure of the active channel layer is always amorphous below 400 ℃ according to X-ray diffraction patterns. No significant change in the band gap energy of the films was observed after the annealing treatment, with E g approximately equal to 3.6 eV. As the annealing temperature increased, the mobility and on/off current ratio initially increased and then decreased, with the threshold voltage always showing a decrease. The evolution of the on/off current and threshold voltage was attributed to the variation of the electron concentration with increasing annealing temperature, according to the Hall measurement. The evolution of the mobility was attributed to the effect of the annealing treatment on the sub-gap state density and defects in the films.