Strain distribution of mbe grown ge_xsi_1-x/si layers by raman scattering

The strain distribution of strained layer superlattice (SLS) as a function of the distance from the interface has been studied by Raman Spectroscopy. A small angle bevel was made by angle lapping on a given thick GexSi1-x/Si SLS so that it is possible to probe the structure at different thicknesses. The Raman spectrum as a function of the distance from interface is then obtained. The results indicate that, as we move away from the interface, compression strain in the alloy layers decreases, tensile strain in the Si layers increases and lower concentration of crystalline defects are present as observed from linewidth measurement.