Abstract |
We investigated the effect of rapid thermal annealing (RTA) temperature report on oxygendeficient rutile TiO2-x thin-film transistors deposited by RF magnetron sputtering. Amorphous TFTs that use TiO2-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 TiO2-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 TiO2-x region acted as traps for electrons and led to carrier transport behavior. The TFT based on a TiO2-x channel layer annealed at 700 °C showed strongly saturated output characteristics, a much higher on/off current ratio of 7.2 × 103 A, electron mobility of 0.15 cm2/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.
(Received March 12, 2019; Accepted May 17, 2019) |
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Key Words |
thin films, sputtering, surface, X-ray diffraction, rapid thermal annealing |
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