Improved amorphous indium gallium zinc oxide thin film transistors by low power RF-sputtering deposition using Ta₂O₅ dielectric

In this paper, the electrical properties of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFT) have been improved using high-k dielectric material Ta₂O₅. The performances of TFTs were investigated using simple and low cost e-beam deposited dielectric as well as using low power and low pressure during channel material deposition by sputtering. In addition, the performances were evaluated using two different channel widths at a fixed channel length. The experimental results have indicated that, using the lower size of channel width of 1000 μm, it could be obtained electrical performance parameters such as the threshold voltage, I_on to I_off ratio, sub-threshold swing voltage, and field effect mobility to be 0.26 V, 10⁷, 0.12 V/decay, and 30.07 cm²/V.s, respectively. The excellent performance of a-IGZO TFT using high-k gate dielectric has shown the great potential for its applications in high quality displays and organic lighting technology.