Structure and normal incidence soft-x-ray reflectivity of Ni-Nb/C amorphous multilayers

摘要

Multilayers for the water window region of the soft x rays have been prepared by pulsed laser ablation with amorphous Ni50Nb50 and amorphous C. The structural characterization of the multilayers, period d = 2.41 nm, shows that the interfaces are sharp with a roughness of only 0.4 nm that is chemical, not morphological, in origin. The interface roughness was found to be uncorrelated in the direction normal to the plane of the film. The normal incidence soft-x-ray reflectivity of the multilayer at 4.85-nm wavelength is 0.06%, 1 order of magnitude lower than the theoretically predicted value. However, the resolution limit lambda/Delta lambda of the multilayer was found to be 16.7, close to the theoretically predicted value. (C) 1997 Optical Society of America.