OPTICAL-CONSTANTS OF VERY THIN GOLD-FILMS IN THE SOFT-X-RAY REGION

The optical constants, delta = 1 - n and kappa, of very thin gold films have been determined from the reflectance data obtained in the soft x-ray region of 60-900 eV. The gold films were prepared to various thicknesses, d = 49 - 270 angstrom, by ion beam sputtering (IBS) and electron beam evaporation (EB). A plane parallel slab model with due considerations for the surface and the interface roughness was employed to analyze the reflectance data by least-squares curve fitting. The optical constants determined for the IBS samples definitely show their dependence on the film thickness. It is also found that delta of the 201-angstrom thick IBS film is smaller by approximately 10% than that of the EB film of 212 angstrom thick.