The effects of grown-in stresses and applied stresses upon interdiffusion in long-period Si0.7Ge0.3/Si were studied by using X-ray diffraction and Raman spectroscopic techniques. Both symmetrically and asymmetrically strained superlattices were used, and activation energies of 3.9 and 4.6eV, respectively, were found for interdiffusion. Enhanced interdiffusion was also detected when an asymmetrically strained superlattice was subjected to an external tensile stress during annealing. In both types of superlattice, enhanced interdiffusion was observed whenever the Si barrier layers were subjected to tensile stresses during annealing. The Raman results indicated that enhanced Ge diffusion into the Si barriers occurred when these barriers were subjected to a tensile stress. The results were explained in terms of the kinetics of defect formation and motion in the strained Si barriers.

S.M.Prokes: Materials Science and Technology, 1995, 11[4], 389-95