Solution-Processed Amorphous In–Zn–Sn Oxide Thin-Film Transistor Performance Improvement by Solution-Processed Y₂O₃Passivation

We report the effect of water-based Y2O3passivation on the performances of solution-processed amorphous indium-zinc-tin oxide (a-IZTO) thin-film transistors (TFTs) employing a solution-processed ZrOxgate insulator. The Y2O3passivation increases the saturation mobility (μsat) and the current ratio (ION/OFF) from 1.64 ± 0.70 to 4.75 ± 0.87 cm2V-1s-1and from 108to 109, respectively, and decreases the hysteresis voltage (VH), subthreshold swing, and threshold voltage (Vth) from 0.09 ± 0.09 to 0 V, from 147.44 ± 44.55 to 114.29 ± 15.06 mV/decade, and from 0.54 ± 0.21 to 0.42 ± 0.23 V, respectively. The threshold voltage shift under positive gate bias stress is also reduced from 1.78 to 0 V. The improvements can be explained by the diffusion of Y into a-IZTO. Yttrium concentration in the a-IZTO active layer is found to be ~16 at.%, which leads to the decrease in oxygen vacancy and hydroxyl group concentrations, and to the increase in M-O-M bond concentration at the a-IZTO/ZrOxand a-IZTO/Y2O3interfaces.