High-performance ZnO Thin-Film Transistors Prepared by Atomic Layer Deposition at Low Temperature

High-performance ZnO thin film transistors (TFTs) are fabricated by atomic layer deposition (ALD). The effects of the deposition temperature of ZnO active layer (80, 100, 120, and 140°C) on performance of TFTs are investigated. Devices with ZnO active layer deposited at 120°C exhibit the best performance, such as a field-effect mobility of 31.79 cm
²
V
^-1
s
^-1
, a sub-threshold slope of 181 mV/decade, an on/off state current ratio over 10
⁹
. Besides, the devices show -0.22 and 0.19 V threshold voltage shift under positive and negative gate-bias stress.