BRILLOUIN-SCATTERING DETERMINATION OF THE ELASTIC-CONSTANTS IN SUPPORTED GE FILMS

Brillouin scattering from supported Ge films, prepared by rapid therma l processing chemical vapor deposition (RTPCVD) and plasma-enhanced ch emical vapor deposition (PECVD) techniques, is carried out in the back scattering geometry. The phonon spectra are analyzed and simulated by taking the ripple and elasto-optic coupling into account, which leads to an accurate determination of the elastic constants. It is found tha t these constants are strongly dependent on deposition methods. In add ition, we have also studied the influence of the interdiffusion in the interfacial layer on the elastic properties.