X-ray Multiple-Beam Analysis in High-Resolution Diffractometry of III–V Heterostructures

High-resolution X-ray diffractometry is used to measure such parameters of heteroepitaxic III–V layers as the substrate miscut angle α, the relative lattice parameter perpendicular (Δa_⊥/a_s) and parallel (Δa_||/a_s) to the interface, and the epitaxic layer tilt angle β. X-ray multiple simultaneous diffraction is expected to provide more structural information and possibly to simplify the analysis. In this paper, a coplanar multiple diffraction system using Co Kα₁ radiation, a monolithic beam conditioner, (004) and (115) simultaneous diffractions, and an oscillating slit is analysed. It is concluded that with this method two measurements are sufficient to obtain the values of (Δa_⊥/a_s), (Δa_||/a_s), the layer tilt angle β and the substrate miscut angle α. Moreover, the absolute value of the substrate lattice parameter can be obtained.