Synchrotron x-ray topographic and high-resolution diffraction analysis of mask-induced strain in epitaxial laterally overgrown GaAs layers

Abstract

Synchrotron x-ray back reflection section topographs of epitaxial lateral overgrown (ELO) GaAs samples grown on (001) GaAs substrates show images of the GaAs layers bent due to the interaction between the layer and the SiO2 mask. The topographs are simulated under the assumption of orientational contrast. Using the same data the measured x-ray diffraction curve is simulated. The calculations, which are in good agreement with the measurements, are used to gain information on the tilted (001) lattice planes in each ELO layer. We show that the bending of ELO lattice planes reaches a maximum at the center of the ELO stripes, where misorientation is at a minimum, and decreases towards the edges of the stripes, where misorientation reaches a maximum.