APPLICATIONS OF MULTIPLE-CRYSTAL DIFFRACTOMETRY

The elucidation of the structure of semiconductor multilayers can be adequately determined by x-ray methods but the interpretation is not always straightforward. In this paper we introduce the idea of full three-dimensional diffraction-space mapping to obtain information on the three-dimensional structure of imperfect materials. We also stress the importance of this method for the interpretation of the data from high-resolution x-ray diffractometry. The presence of defects and diffraction effects can create significant changes to the diffraction pattern that require a more complete analysis than that obtained from simple profiles. These subtle influences can in general only be understood by diffraction-space mapping. interpretation of diffraction-space maps from the high-resolution multiple-crystal multiple-reflection diffractometer permits the use of three extra very powerful tools. The first is multiple-crystal topography so that the diffraction-space intensity features can be related to lateral contrast on the photographic emulsion, the second is the accurate determination of lattice parameters and the third is the simulation of the diffraction shapes using dynamical theory.