Indium Oxide Thin-Film Transistors Fabricated by RF Sputtering at Room Temperature
Thin-film transistors (TFTs) were fabricated using an indium oxide (In<sub>2</sub>O<sub>3</sub>) thin film as the n-channel active layer by RF sputtering at room temperature. The TFTs showed a thickness-dependent performance in the range of 48-8 nm, which is ascribed to the total carrier number in the active layer. Optimum device performance at 8-nm-thick In<sub>2</sub>O<sub>3</sub> TFTs had a field-effect mobility of 15.3 cm<sup>2</sup> · V<sup>-1</sup> · s<sup>-1</sup>, a threshold voltage of 3.1 V, an ON-OFF current ratio of 2.2 × 10<sup>8</sup>, a subthreshold gate voltage swing of 0.25 V · decade<sup>-1</sup>, and, most importantly, a normally OFF characteristic. These results suggest that sputter-deposited In<sub>2</sub>O<sub>3</sub> is a promising candidate for high-performance TFTs for transparent and flexible electronics.