Characterization of roughness correlations in W/Si multilayers by diffuse x-ray scattering

We present diffuse, nonspecular x-ray measurements of the interface height-height self-correlations in an amorphous WlSi multilayer. The measurements have been performed in a scattering geometry that is placed out of the plane of reflection, giving access to a much lar- ger range in parallel momentum transfer than in conventional nonspecular geometries. For the sample studied a logarithmic form of the correlation function is found.