Lateral inhomogeneities of sapphire plates determined with the aid of X-ray and probe methods

X-ray diffractometry, X-ray profilometry, atomic-force microscopy, and sclerometer tests are employed in the study of $R$-cut plates of sapphire single crystals grown with the aid of the Kyropoulos technique and used as substrates for the silicon-on-sapphire structures. Regions with different degrees of perfection can be found even on a single plate. Mutually consistent results of the four experimental methods based on different physical principles can be used to reveal regions of structural imperfection on the surface of a plate. It is expedient to employ a complex procedure for multipoint monitoring of the parameters of plates to reduce the number of defect samples that serve as substrates in the production of electronic devices.