Influence of surface roughness on near‐surface depth analysis from X‐ray reflectivity measurements

X‐ray reflectometry is a powerful tool for investigations of rough surfaces and interface structures. However, in previous studies, the calculation of the X‐ray reflectivity often show a strange effect where interference effects would increase at a rough surface. Here, we propose that this unexpected result of such calculations of the X‐ray reflectivity originates in a neglect of the effect of a decrease in the intensity of refracted X‐rays due to diffuse scattering at a rough surface and interface. In the present study, we present a new, accurate analysis of the X‐ray reflectivity from a multilayer surface taking into account roughness‐induced diffuse scattering. We calculated the X‐ray reflectivity for the W/Si system using a reduced Fresnel transmission coefficient at a rough surface and interface. The calculated reflectivity using this approach gave a physically reasonable result. A new approach using a reduced Fresnel transmission coefficient at a rough surface and interface allowed us to calculate physically reasonable values of the X‐ray reflectivity. Copyright © 2010 John Wiley & Sons, Ltd.