Surface Waves and Strain Modulations in Si1-xGex Alloy Layers on Si

Abstract

ABSTRACTThe growth of strained, continuous Si1-xGex epitaxial alloy layers on Si can, under certain conditions, result in the occurrence of marked, small-scale layer thickness fluctuations in the form of crystallographically-aligned, interlocking ripple arrays. In the present work, combined transmission electron microscope (TEM) and atomic force microscope studies are employed to reveal the detailed nature of these surface ripples. TEM contrast studies demonstrate that well-defined, oscillatory strain variations accompany these ripple structures, the presence of which is shown to be associated with partial elastic strain-relief and lowering of the energy of die strained-layer system.