Images of local tilted regions in strain-relaxed SiGe layers

Strain-relaxed Si1-xGex films have been investigated using X-ray microdiffr action with a diffracted beam footprint of 0.3 mu m x 2 mu m. Intensity var iations in the diffracted beam at different positions on the sample are due to the presence of local tilted regions which are larger in area than the diffracted X-ray beam. These regions are shown to have the same lattice par ameter but different orientation with respect to the Si substrate. These re gions arise from dislocation pileups, which consist of a larger number of d islocations when larger mismatch strain is relieved. (C) 1999 Elsevier Scie nce B.V. All rights reserved.