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 degrees C.