X-RAY MULTIPLE-BEAM ANALYSIS IN HIGH-RESOLUTION DIFFRACTOMETRY OF III-V HETEROSTRUCTURES

High-resolution X-ray diffractometry is used to measure such parameter s of heteroepitaxic III-V layers as the substrate miscut angle alpha, the relative lattice parameter perpendicular (Delta a(perpendicular to )/a(s)) and parallel (Delta a(parallel to)/a(s)) to the interface, and the epitaxic layer tilt angle beta. X-ray multiple simultaneous diffr action is expected to provide more structural information and possibly to simplify the analysis. In this paper, a coplanar multiple diffract ion system using Co K alpha(1) radiation, a monolithic beam conditione r, (004) and (115) simultaneous diffractions, and an oscillating slit is analysed. It is concluded that with this method two measurements ar e sufficient to obtain the values of (Delta a(perpendicular to)/a(s)), (Delta a(parallel to)/a(s)), the layer tilt angle beta and the substr ate miscut angle alpha. Moreover, the absolute value of the substrate lattice parameter can be obtained.