INTERFACE STRUCTURE OF MBE-GROWN COSI2 SI/COSI2 LAYERS ON SI(111) - PARTIALLY CORRELATED ROUGHNESS AND DIFFUSE-X-RAY SCATTERING/

The detailed interface structure of a CoSi2/Si/CoSi2/Si(111) layer sys tem grown by molecular-beam epitaxy is investigated in this paper. Mea surements of the diffuse scattering in the region of total external re flection were performed and analyzed within the distorted-wave Born ap proximation. The analysis of the specularly reflected and the diffusel y scattered intensity leads to a consistent set of interface and layer parameters, which are compared with results of Rutherford backscatter ing/channeling, transmission electron microscopy, and scanning tunneli ng microscopy. Although the diffuse intensity is dominated by a very r ough surface layer, the roughness distribution of the buried interface s of the epitaxial layers was determined rather exactly. It was found that the roughnesses of the interfaces of all epitaxial layers are of the order of monolayer steps. Very good agreement between the measurem ents and the calculations is achieved, if conformal roughness of the a djacent interfaces of each CoSi2 layer is included. Furthermore, the i nterfaces of the sandwiched Si layer are partially correlated, which m eans that the step structure is partially transferred through all inte rfaces up to the surface of the upper CoSi2 layer.