X-RAY-DIFFRACTION ANALYSIS OF GAAS/ALAS MULTILAYER STRUCTURES GROWN BY MOLECULAR-BEAM EPITAXY ON (311) AND (210) GAAS-SURFACES

In this work, we investigate the structural properties of single and multiple AlAs/GaAs heterostructrues grown on (311) and (210) AaAs surfaces by molecular beam epitaxy. The strain state and lattice deformation of epitaxial layers gron on high-index surfaces is determined. The components of the strain tensor are calculated by minimizing the strain-energy density and are implemented in the normalized strain function of the Takagi-Taupin equations of the dynamical X-ray diffraction theory for distorted crystals in order to simulate the experimental X-ray diffraction patterns. Experimental results on AlGaAs single heterostructures and AlAs/GaAs multilayer Structures reveal that the epitaxial layers are pseudomorphic and show a shear strain component different from zero in contrast to structures grown on (001) substrates surfaces. The measured data are in excellent agreement with the calculated strain fields.