Measurement of stress and relaxation in Si1-xGex layers by Raman line shift and x-ray diffraction

Micro Raman backscattering, X-ray double crystal diffractometry and transmission electron microscopy are used to investigate the epitaxial Si(1-x)Ge(x) layers, grown by molecular beam epitaxy. The epitaxial Si(1-x)Ge(x) layers, grown by chemical vapor deposition on Si substrates with thickness between 20 and 50 nanometers, are also investigated. The Raman shift of the Si-Si mode as a function of the germanium content is also derived by a simple phenomenological model. The Raman shift also yields the degree of relaxation, independently determined from the germanium content.