Highly Stable, Solution-Processed Ga-Doped IZTO Thin Film Transistor by Ar/O2 Plasma Treatment

The effects of gallium doping into indium-zinc-tin oxide (IZTO) thin film transistors (TFTs) and Ar/O-2 plasma treatment on the performance of a-IZTO TFT are reported. The Ga doping ratio is varied from 0 to 20%, and it is found that 10% gallium doping in a-IZTO TFT results in a saturation mobility (mu s(at)) of 11.80 cm(2) V-1 s(-1), a threshold voltage (V-th) of 0.17 V, subthreshold swing (SS) of 94 mV dec(-1), and on/off current ratio (I-on/I-off) of 1.21 x 10(7). Additionally, the performance of 10% Ga-doped IZTO TFT can be further improved by Ar/O-2 plasma treatment. It is found that 30 s plasma treatment gives the best TFT performances such as mu s(at) of 30.60 cm(2) V-1 s(-1), V-th of 0.12 V, SS of 92 mV dec(-1), and I-on/I-off ratio of 7.90 x 10(7). The bias-stability of 10% Ga-doped IZTO TFT is also improved by 30 s plasma treatment. The enhancement of the TFT performance appears to be due to the reduction in the oxygen vacancy and -OH concentrations.