Preparation of ultrathin HfO 2 films and comparison of HfO 2 /SiO 2 /Si interfacial structures

Stoichiometric HfO 2 films were successfully prepared using both thermal oxidation of Hf metal film and direct reactive sputtering deposited on native SiO 2 /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 HfO 2 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 © 2004 John Wiley & Sons, Ltd.