An x-ray rocking curve technique for the absolute characterization of epitaxial layers and single-crystal solids

Abstract

A rapid double-crystal x-ray diffractometer technique for the absolute measurement of lattice parameters in single crystals and epitaxial layers is introduced. The method is based on the principle that in a diffractometer aligned for rocking curve measurements within a given zone, the zero setting correction is the same for all crystal angles within the zone. The peak positions can thus be measured and corrected quickly, and the lattice parameters evaluated within each layer independently of others. The proof-of-principle tests are given for Si and InP, and the method is applied to a GaN film grown on an a-plane sapphire wafer. The method has unlimited accuracy depending only on the instrumental alignment and material quality.