Grazing incidence diffraction by epitaxial multilayered gratings

Multilayered gratings have been investigated by high-resolution grazing incidence diffraction, employing non-coplanar triple crystal diffractometry. A theoretical treatment has been developed based on the distorted wave Born approximation for multilayer diffraction. Grazing incidence diffraction reveals as an optimal complement to symmetrical and asymmetrical high-resolution X-ray diffraction. The method allows to measure separately the influences of the lateral strain and the grating shape. Depth selective studies have been performed by surface gratings and buried gratings showing for the first time the evolution of the strain relaxation phenomena in strained InGaAsP surface gratings resulting from burying in InP