Effect of annealing temperature on the electrical properties of In-Zn-Li-O thin film transistors

InZnLiO thin film transistors with the bottom gate structure were fabricated by radio frequency magnetron sputtering. The structure of InZnLiO channel layers were studied by SEM and XRD. The electrical properties on the effect of the annealing temperature were investigated. As the annealing temperature increased, the field effect mobility and the on/off current ratio increased observably, and the threshold voltage was shifted to the negative direction. But when the temperature was too high, the electrical properties of InZnLiO TFTs deteriorated significantly. In all, the transistor annealed at 950 °C exhibited the best performance, with a field effect mobility of 63.1 cm2/V s, an on/off current ratio of 6.9 × 106, and a threshold voltage of 0.2 V.