Weak‐beam contrast of stacking faults in transmission electron microscopy

Stacking faults (and other planar defects) imaged under weak‐beam conditions can exhibit pronounced contrast changes if the sign of the diffraction vector or of the excitation error is changed. This contrast behaviour has not yet been understood. In this paper, the contrast of weak‐beam images of stacking faults in silicon is studied systematically; the faults are subsequently unambiguously characterized by direct lattice imaging. Other related planar defects in silicon, stainless steel, and a copper alloy are also investigated. Extrinsic stacking faults are found to show significant contrast asymmetries while intrinsic faults did not. A simple theory is presented which taking into account the finite thickness of an extrinsic stacking fault can explain most of the observed contrast phenomena. Copyright © 1980 WILEY‐VCH Verlag GmbH & Co. KGaA