CHARACTERIZATION OF III-V HETEROEPITAXIAL LAYERS BY X-RAY-DIFFRACTION

GaAl(As)Sb/GaSb heterostructures grown in our institute are studied by precise x-ray diffractometry. The films were deposited by liquid-phas e epitaxy on GaSb wafers. Experimental data are obtained using the par allel setting of an x-ray double-crystal diffractometer. Information o n the strain-depth profile, the number of layers and the component lay er thicknesses is extracted from the measured pattern by comparing it with a simulated pattern. A simple transparent method of calculating t he x-ray reflection coefficient of the single crystal with a layer is described. A Penning and Polder type approach for the perfect crystal is used. The crystal film was considered as a sequence of homogeneous lamellae having varying lattice parameters and thicknesses.