Achieving High Mobility in IGTO Thin-Film Transistors at a Low Temperature via Film Densification

The effects of chamber pressure (
P
_C
) on the structural and chemical properties of an indium gallium tin oxide (IGTO) channel layer were examined. Smoother and denser IGTO films were obtained with decreasing
P
_C
, which were explained based on the enhanced kinetic energy of sputtered particles due to fewer collisions with the plasma atmosphere. The resulting IGTO thin-film transistor exhibited a high mobility of 35.0 cm
²
/Vs, subthreshold gate swing of 0.17 V/decade, threshold voltage (
V
_TH
) of -0.45 V, and
I
_ON/OFF
ratio >10
⁸
, even at a low annealing temperature of 150 °C.