Effect of ozone concentration on atomic layer deposited HfO2 on Si

Abstract

Effect of ozone concentration (200-400 g/Nm3) on atomic layer deposition of HfO2 thin films on Si wafers using tetrakis (dimethylamino)hafhium (TDMAHf) as Hf precursor was systematically studied. High-resolution transmission electron microscopy and x-ray photoelectron spectroscopy analyses show that oxidation of the Si substrate enhances with ozone concentration which leads to an increase in interfacial layer (TL) thickness between the high-k dielectric and the substrate. The relatively thicker IL successfully suppresses additional growth of itself and Si out-diffusion into the dielectric during post deposition annealing (PDA). Corresponding electrical characteristics such as capacitance-voltage, leakage current density and time zero dielectric breakdown display significant improvement for HfO2 film prepared using higher ozone concentration after PDA.