Grazing-incidence diffraction study of strain-modulated single quantum well nanostructures

The strain distribution of a lateral nanostructure containing an InGaAs single quantum well (SQW) is studied by depth-resolved high-resolution x-ray grazing-incidence diffraction. The lateral strain variation is realized by patterning of an initially tensily strained InGaP stressor grown on top of the compressively strained SQW. The finite element method (FEM) is applied to the analysis of the strain distribution within the SQW induced by strain relaxation of the stressor layer. In particular, it is shown that the strain field reaches a maximum beneath the valleys and varies with the valley width. Based on the distorted wave Born approximation the experimental x-ray scattering curves were simulated using the displacements calculated by FEM as an input. We found a rather good agreement between simulation and experiment.