Characterization of magnetron sputtered rhodium films for reflective coatings

Preparation and detailed characterization of metallic rhodium films prepared by magnetron sputtering on silicon substrates have been carried out. Different deposition conditions such as gas pressure, deposition rate and substrate temperature were investigated. The films were characterized by XPS, SEM, XRD, AFM and reflectivity measurements. No impurities were detected on the surface after deposition. The films have a low roughness and their structure exhibit nanometric crystallites with a dense columnar structure. Amongst all investigated parameters, only the gas pressure during deposition was observed to have an influence on the optical properties of the film. Otherwise, the measured reflectivity is close to the reflectivity calculated from optical constants of pure rhodium films.