An Electron Microscope Method for Determining the Nature of Stacking Faults in F.C.C. Materials which Does not Rely on Effects of Absorption

Abstract

Previous methods for determining whether stacking faults in f.c.c. materials are extrinsic or intrinsic make use of an asymmetry in dark field images which is due to the effects of absorption. As a result, the techniques are more difficult to apply in thinner regions of a crystal and in crystals with low absorption, such as silicon. A method for determining the nature of stacking faults in f.c.c. materials is presented which does not depend on absorption effects. The method makes use of an asymmetry in bright field images which is obtained when non-symmetrical Laue diffraction conditions prevail and/or the stacking fault is inclined so that the column approximation is not valid. These images can provide sufficient information to apply either the method of Hashimoto et al. or the method of Gevers et al. with the rules for the direction of the reciprocal lattice vector reversed.