Achieving high performance thin film transistors based on gallium doped indium zinc tin oxide

In this paper, staggered bottom-gate amorphous oxide thin film transistors with a channel layer of gallium doped indium-zinc-tin oxide (IZTO:Ga) have been fabricated by radio frequency magnetron sputtering at room temperature on SiO2/Si substrate. Under the annealing treatment at 350 °C in air atmosphere, the IZTO:Ga films still kept amorphous and the transmittivity of the IZTO:Ga film was over 80% in the visible range. The IZTO:Ga TFTs showed desired performance with saturation mobility of 36.3 cm2V−1s−1, subthreshold swing value of 0.42 V/decade, current on/off (Ion/Ioff) up to 109 with the off current as low as 4.5 × 10−13 A and exhibited the enhancement mode with a threshold voltage of 1.0 V. Besides, the positive and negative bias stability of the IZTO:Ga TFTs without passivation is also measured in air with the stress time up to 3600 s and the threshold voltage (VTH) showed a shift for +4.6 V and −5.4 V respectively.