High Mobility Hf-In-ZnO TFTs, with HfO2 as Dielectric for Low Voltage Operation Range

In this paper we present high mobility thin film transistors, using hafnium oxide as dielectric and amorphous Hafnium-Indium-Zinc Oxide as semiconductor, both deposited by radio frequency magnetron sputtering at room temperature. Devices operated within the voltage range of 2 V, with mobility above 300 cm2/Vs and a threshold voltage in the order of 0.6 V. When the value of the effective mobility is above 150 cm2/Vs, as the gate voltage increases, its behavior presents a maximum with a further reduction. This can be interpreted as a crystalline-like behavior, although the semiconductor layer completely is amorphous.