Xhyphen;ray analysis of strain relaxation in strainedhyphen;layer superlattices

摘要

Theoretical simulations of xhyphen;ray doublehyphen;crystalhyphen;diffraction rocking curves for strainhyphen;relaxed superlattices have been successfully carried out based on xhyphen;ray dynamical diffraction theory. The strain relaxation, the misorientation between the superlattice layers and the substrate, and the effect of peak broadening due to the formation of misfit dislocations have been taken into account. The influence of possible strain relaxation mechanisms and relaxation ratios on the rocking curves have been investigated. It was found that both the mechanism and degree of the strain relaxation of the superlattice can be determined by fitting the angular positions and the relative intensities of the experimental superlattice satellites. By using this method, an InxGa1minus;xAs/GaAs superlattice sample and a GexSi1minus;x/Si superlattice sample were analyzed. The different strainhyphen;relaxation mechanisms were found in these two samples.