Thickness Effects of Active Layers on the Properties of Zinc Tin Oxide Transparent Thin Film Transistors

Abstract: Transparent thin film transistors were fabricated on n+-Si wafers coated by Al2O3/SiO2. Zinc tin oxide (ZTO) films deposited by rf magnetron sputtering were employed for active layers. The mobility (μs), threshold voltage (VT), and subthreshold swing (SS) dependances on ZTO thickness were analyzed. The VT decreased with increasing ZTO thickness. The μs raised from 5.1 cm2/Vsec to 27.0 cm2/Vsec by increasing ZTO thickness from 7 nm to 12 nm, and then decreased with ZTO thickness above 12 nm. The SS was proportional to ZTO thickness