Formation of Particulate Fe-Al Films by Selective Oxidation of Aluminum

摘要

Fe-5wt%Al films were RF-sputtered and annealed in an atmosphere of hydrogen and water vapor mixture at 1173 K for up to 200 min in order to selectively oxidize aluminum. As the annealing time increased, the morphology of the films changed from the continuous to the discontinuous type; thus, particulate Fe-Al films formed after 100 min. Thermodynamics simulation was performed to determine the ideal conditions for this process. Temperatures exceeding 1073 K are necessary to prevent iron from oxidation confirmed by both the depth profile in XPS and magnetic moment increment in VSM. Annealing the films in an atmosphere with a very low dew point of 77 K did not make the films become particulate. New findings are expected to be applied to the thin film inductors for GHz application as well as to manufacturing process of nanoparticles.