High-Mobility IGZO TFTs by Infrared Radiation Activated Low-Temperature Solution Process

This letter presents high-mobility thin-film transistors (TFTs) based on InGaZnO by a novel infrared (IR) radiation activated low-temperature solution process. A high mobility of over 60 cm
²
V
^-1
s
^-1
, an I
_ON
/I
_OFF
ratio of 10
⁶
, and a decreased operating voltage of 4 V were achieved at 230 °C. This mobility was four times higher than that of a device by high-temperature (450 °C) annealing, and was comparable to those of oxide TFTs previously produced via vacuum or high-temperature processes. The synergistic IR radiation and thermal energy mechanism resulted in more effective removal of precursor impurities, a more extensive metal-oxygen lattice, and more oxygen vacancies to serve as charge carriers, which contributed to the much higher performance achieved with IR radiation. Moreover, the IR-processed devices exhibited excellent operational stability with a small V
_th
shift under bias stress. Our results may provide new low-temperature solution routes to highperformance TFTs.