Investigations on Compositional, Structural and Optical Properties of Thermally Oxidized HfO2 Films

Thermal oxidation at various temperatures on magnetron sputtered hafnium films shown significant effect on stoichiometry, crystallographic structure and electrical and optical properties. X-ray photoelectron spectroscopy confirms the stoichiometry of HfO2 films by showing the relevant shift in the core level binding energies of hafnium and oxygen after increasing the oxidation temperature to 600 °C. The EDAX analysis also confirmed the required composition of HfO2 films. The presence of monoclinic HfO2 structure was identified by XRD for the films oxidized at 600 °C. The interface quality at HfO2/Si stacks was improved as a function of oxidation temperature. The optical band gap and the refractive index of the HfO2 films increased with increase of oxidation temperature.