Preparation of ultrathin HfO2 films and comparison of HfO2/SiO2/Si interfacial structures

摘要

Stoichiometric HfO2 films were successfully prepared using both thermal oxidation of Hf metal film and direct reactive sputtering deposited on native SiO2/Si wafer. Angle-resolved x-ray photoelectron spectroscopy, Auger depth profiling and grazing incident x-ray reflectivity have been exploited to study the interfacial structures of the generated HfO2 films. A thinner interface (about 1.2 nm) of Hf-rich silicates is formed using thermal oxidation, while the reactive sputtering deposition leads to a thicker (about 3.2 nm) Si-rich interface. The results of binding energy, chemical composition, thickness and density all indicate that both interfaces have a graded structure where the concentration of Hf in the silicate interlayer decreases gradually along the depth. Copyright (C) 2004 John Wiley Sons, Ltd.