Abstract

The scattering of radiation (e.g., X-rays or neutrons) by multilayer films containing interface roughness is discussed. As is by now well known, such interface roughness usually possesses a degree of conformality (i.e., correlations between different interfaces), which is known to produce structure in the diffuse scattering which mimics that in the specular reflectivity [1-6]. There are more subtle effects when either the incident or scattered wave vector is close to the condition for specular Bragg reflection from the multilayer, which have also been noted [7]. Such effects can be treated within the framework of the Distorted Wave Born Approximation (DWBA) [8-10], which can also be thought of as including “double-scattering” (i.e., Bragg + diffuse scattering) processes. Interesting effects in the diffuse scattering (i.e., sharp minima or edges) manifest themselves in the line shapes observed for rocking curves at these positions, and these can be qualitatively explained within the framework of the dynamical theory of diffraction by considering the effects of correlated interface roughness. Such correlated roughness can produce both constructive and destructive interference in the dynamically scattered waves. The theory is illustrated with Synchrotron X-ray diffuse scattering studies from several Nb/Si multilayer samples [11].

© 1994 Optical Society of America