Structural characterization of ultrathin Cr and Sc films for soft X-ray mirrors

The structure of multilayers of ultrathin scandium (Sc) and chromium (Cr) films has been characterized by means of transmission electron microscopy (TEM). Face centered cubic Sc was found both in magnetron sputtered thin Sc layers on Si(001) and in Cr/Sc multilayers for soft X-ray mirrors. The single Sc and Cr layers are polycrystalline with randomly oriented grains, while Sc and Cr within the Cr/Sc multilayer show a strong [001] texture in the deposition direction. From high-resolution images the orientation-relationship at the Cr/Sc interfaces could be deduced as: Sc[110]//Cr[100] and Sc [010]//Cr[110], which was confirmed by image simulations.