X-RAY DETERMINATION OF THE DISLOCATION DENSITIES IN SEMICONDUCTOR CRYSTALS USING A BARTELS 5-CRYSTAL DIFFRACTOMETER

Recently, a general technique for the measurement for the threading dislocation densities in epitaxic semiconductors by high-resolution X-ray diffraction was reported [Ayers (1994). J. Cryst. Growth, 135, 71-77]. Here, this method has been extended to the case of a Bartels five-crystal diffactometer by making use of known instrumental effects for this diffractometer. The usefulness of the method has been demonstrated by application of the technique to epitaxic ZnSe grown on GaAs (001) by photo-assisted metalorganic vapor-phase epitaxy. It is shown that in this case the threading dislocation density of the epitaxic layer can be determined quantitatively. Evidence for the introduction of dislocations in the underlying GaAs substrate is also presented.