Interdiffusion in Ge rich SiGe/Ge multilayers studied by in situ diffraction



We report on the investigation of diffusion properties of SiGe/Ge multiple quantum well (MQW) structures with period of 24 nm grown strain symmetrized on relaxed SiGe buffers on Si (001) substrates by molecular beam epitaxy. During in situ annealing, X-ray diffraction experiments were performed on series of MQW structures with average Ge contents of about 70 and 90% using reciprocal space mapping around the (224) reciprocal lattice point. The reciprocal space maps were obtained at elevated temperatures at the ESRF for temperatures from about 600 to 800 °C. The temperatures, where interdiffusion becomes observable, is in the range from 680 to 780 °C for xGe = 0.7 and from 650 to 720 °C for xGe = 0.9. The diffusion parameters were obtained from the analysis of the decay of the periodic satellites in the recorded intensity maps.