Effect of Annealing Temperature on Electrical Properties and Stability of Si–Zn–Sn–O Thin Film Transistors Under Temperature Stress

Abstract

Silicon–zinc–tin–oxide (SZTO) thin film transistors (TFTs) were fabricated by radio frequency magnetron sputtering at room temperature, and the influence of annealing temperature (400–600 °C) on the electrical properties and the stability of the SZTO TFTs were investigated. As the annealing temperature was increased, the electrical properties, such as the field effect mobility, on/off current ratio, and subthreshold swing enhanced because of increase in the carrier concentration and decrease in the trap density. However, a conductor-like behavior was observed at 600 °C owing to a high carrier concentration. The stability of the SZTO TFTs was measured in the temperature range of 300–333 K under temperature stress (TS). The ∆VTH was measured to be 5.5, and 2.81 V at annealing temperatures of 400 and 500 °C, respectively. These results indicate that defect states decreased and stability enhanced with increase in the annealing temperature because of rearrangement of atoms caused by annealing. The relation between the electrical properties and the annealing temperature was also investigated using the transmission line method, and the total resistance was found to decrease with increase in the annealing temperature, which is in accordance with the result of TS.