Thermal stability of Co/SiO multilayers for use in the soft X-ray region

Ishino, Masahiko; Koike, Masato; Kanehira, Mika*; Sato, Futami*; Terauchi, Masami*; Sano, Kazuo*

The heat stability of Co/SiO multilayers was evaluated. Multilayer samples were deposited on Si substrates by means of the ion beam sputtering method and annealed at temperatures from 100-600 C in a vacuum furnace. For the structural and optical evaluations, small angle X-ray diffraction measurements, soft X-ray reflectivity measurement in the 1 keV energy region, and transmission electron microscopy observations were carried out. As the results, the Co/SiO multilayers annealed up to 400 C maintained the initial multilayer structure and kept almost the same X-ray reflectivity as the as-deposited sample. A deterioration of the multilayer structure caused by the growth of Co grains was found on the samples annealed over 500 C, and the soft X-ray reflectivity dropped in accordance with the deterioration of the multilayer structure.