ANALYSIS OF GRAZING-INCIDENCE X-RAY DIFFUSE SCATTER FROM CO-CU MULTILAYERS

Grazing incidence diffuse X-ray scattering data from a Co-Cu multilaye r with stepped interfaces grown by molecular beam epitaxy on a copper silicide buffer on a silicon substrate has been analysed using a compu ter code based on a fractal interface within the distorted wave Born a pproximation. We have extended the theory to include the scattering fr om a stepped interface and have shown that a single set of structural parameters can be used to obtain an excellent agreement between simula tion and experimental data taken under very different X-ray optical co nditions. The symmetry of the diffuse scatter on rotation about the su rface normal can be explained if it arises from step bunching at the e nds of extensive flat terraces. These steps have a self-affine nature, enabling the fractal model to be used successfully. (C) 1998 Elsevier Science B.V. All rights reserved.