Soft x-ray multilayers fabricated by electron-beam deposition

In this paper, the authors have investigated the optimum deposition conditions for fabricating Mo/Si multilayers on Si wafers by means of electron-beam deposition, taking the substrate temperature and deposition rate as parameters. Mo/Si multilayers made at substrate temperatures of rom temperature to 420 degrees C and at deposition rates of 0.02 to 1.0 nm/s were evaluated by transmission electron micrographs of their cross sections, x-ray diffraction patterns, and their spectral reflectances for soft x rays of 10 to 17 nm. The optimum deposition parameters were found to be 100 to 150 degrees C and 0.02 to 0.2 nm/s, respectively, for substrate temperature and deposition rate. The Mo/Si multilayer made under the optimum condition showed fairly smooth layered structure and a reflectance of ∼30% for unpolarized soft x ray of 14.6 nm at an incident angle of 20 deg