THE DIFFUSE-X-RAY SCATTERING IN REAL PERIODICAL SUPERLATTICES

The X-ray diffraction in real periodical superlattices has been described using a four-dimensional formalism on the basis of the Takagi diffraction theory and an optical coherence approach. This method enabled us to study the diffraction properties of real superlattices containing rough interfaces and other structural defects (precipitates etc.). The interfaces have been described by a statistical model, which takes into account lateral correlations at a rough interface. The theoretical conclusions have been verified by X-ray diffraction measurements on a GaAs AlAs superlattice using a double crystal and a triple crystal diffractometers. From the reflection curve of the 0-th diffraction satellite and from the integrated reflectivities of non-zero satellites the averaged parameters of the lattice have been determined. The statistical parameters of the interfaces were estimated from the shapes of non-zero diffraction peaks. © 1992.