X-Ray scattering from semiconductor interfaces

X-ray diffraction has been used to determine the structure of surfaces over the past decade or so. The concepts involved in surface structure determination may be extended to the study of buried interfaces. A formalism for the determination of the structure of epitaxial interfaces is outlined, together with its application to the NiSi2/Si(111) interface. The use of a grazing incidence diffraction geometry to investigate strain relaxation in latticemismatched epilayers on the monolayer scale is discussed. The technique has been employed to monitor strain relaxation in thin Ge overlayers on Si(001) substrates with greater sensitivity than is attainable using other techniques. The results indicate that strain relaxation in this system relates primarily to islanding on the surface rather than the formation of misfit dislocations.