STACKING-FAULTS IN EPITAXY INVESTIGATED BY SPALEED

Some experimental results on the epitaxy on fcc (111) surfaces indicat e that the lattice sites of the deposited layers can vary between the face-centered cubic and the hexagonal close-packed stacking sequence. Several non-specular beams in SPALEED (spot profile analysis of LEED) are suited to detect quantitatively the registry of islands or flat hi llocks at the surface. Because of the small penetration depth of the e lectrons the localization of stacking faults is mostly limited to the uppermost layer. Deeper-lying stacking faults are proved by a constant phase jump in the scattering factor reducing the peak intensity of th e spot.