Kinetics of Cr2O3 growth during the oxidation of Cr(110)
Fakultät für Physik und Astronomie, Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum - D 44780 Bochum, Germany
Accepted: 10 January 1997
We have studied the oxidation of single crystalline Cr(110) films prepared by molecular beam epitaxy (MBE) in the temperature range from 400 K to 700 K. Epitaxial α- layers in  orientation are formed over the whole temperature range. We monitor the oxidation by X-ray reflectivity measurements providing information on the oxide layer thickness, its defect density and the roughness of the oxide surface and the metal/oxide interface for different times and temperatures. After a rapid increase of the oxide thickness in the early growth stage, we observe a saturation of the oxide thickness. This saturation thickness depends markedly on the oxidation temperature, indicative for an oxidation process which is controlled by the Cr-ion diffusion. The activation energy for the cation diffusion is determined to be 1.4 eV, which is smaller by a factor of two as compared to the value found for bulk interstitial diffusion.
PACS: 81.65.Mq – Surface treatments: oxidation / 81.15.Hi – Molecular, atomic, ion, and chemical beam epitaxy / 61.10.-i – X-ray diffraction and scattering
© EDP Sciences, 1997