Effect of Rapid Thermal Annealing Temperature on Oxygen-Deficient Ti02.x-based Thin-Film Transistors Deposited by RF Magnetron Sputtering

摘要

We investigated the effect of rapid thermal annealing (RTA) temperature report on oxygen-deficient rutile TiO_(2-x) thin-film transistors deposited by RF magnetron sputtering. Amorphous TFTs that use Ti_(2-x) semiconductors as an active layer can be fabricated by low-temperature process and show remarkable electrical performance. The RTA post-annealing process provides greater production and development flexibility, and a fast preparation method. Structural analyses using X-ray diffraction suggested that when the Ti_(2-x) film was annealed at different temperatures (400 °C, 500 °C, 600 °C, and 700 °C) it changed from an amorphous to a rutile phase. The oxygen vacancies in the Ti_(2-x) region acted as traps for electrons and led to carrier transport behavior. The TFT based on a Ti_(2-x) channel layer annealed at 700 °C showed strongly saturated output characteristics, a much higher on/off current ratio of 7.2 x 10~3 A, electron mobility of 0.15 cm~2/Vs, a threshold voltage of 0.4 V, and a subthreshold swing of 0.31 V/dec. However, when the temperature of the RTA was 700 °C, the stability and reliability of the TFT was reduced and surface roughness increased, thereby reducing the mobility of the element charges, as well as leakage current.