Remarkable Increase in Field Effect Mobility of Amorphous IZTO Thin-Film Transistors With Purified ZrOx Gate Insulator

We report the effect of purification of ZrO
_x
precursor on the performance of solution processed amorphous indium-zinc-tin oxide thin-film transistors with a ZrO
_x
gate insulator, which is processed at the maximum temperature of 300 °C in air. By purification, the saturation mobility (μ
_sat
) increases from 2.45 ± 0.83 to 15.42 ± 4.01 cm
²
V
^-1
s
^-1
, subthreshold swing decreases from 141.44 ± 14.08 to 87.90 ± 11.05 mV/decade and drain current ON/OFF ratio increases from ~10
⁷
to ~10
⁹
. The leakage currents are remarkably reduced by using purified ZrO
_x
as a gate insulator. The improvement is mainly due to the reduced impurities and less oxygen vacancies in ZrO
_x
.