CHARACTERIZATION OF SI GE INTERFACES BY DIFFUSE-X-RAY SCATTERING IN THE REGION OF TOTAL EXTERNAL REFLECTION/

Four samples with different numbers of Si/Ge-bilayers were grown at th e same time by high vacuum vapor deposition onto Si(111)-substrates at room temperature. Diffuse scattering experiments within the region of total external reflection were carried out to investigate the mesosco pic roughness of the interfaces. The data are explained quantitatively using the distorted wave Born approximation (DWBA) for correlated lay er systems with self-affine interfaces. Because all samples were grown under identical conditions the interface parameters of the simpler sy stems were used for the more complex samples in order to reduce the nu mber of free parameters in the refinement. The resulting trends for th e roughness amplitude and the in-plane correlation lengths are compare d to predictions from different growth models.