QUANTITATIVE DOUBLE-CRYSTAL X-RAY DISPERSION TOPOGRAPHY WITH A POINT FOCUS SOURCE

The X-ray topographic method described by Nittono and Shimizu [J. Crys tal Growth 45 (1978) 476] is discussed. The method uses a high dispers ive setting of a double-crystal spectrometer and a point focus source. Formulas for interpretation of the topographs are derived and discuss ed especially for the investigation of the thin epilayers. The frequen t case of the curved sample is also considered. The employment of this method is illustrated by several topographs of liquid phase epitaxy ( LPE) layers.