Elastic Relaxation Evaluation in SiGe/Si Hetero-Epitaxial Structures

Abstract

In this paper, the impact of downscaling the geometry on the stress levels of SiGe/Si hetero-epitaxial structures is investigated by two different experimental techniques, i.e., Raman spectroscopy and High-Resolution X-ray diffraction analysis. The experimental results are complemented by finite element stress simulations. It is shown that the lowest stress levels are obtained for window sizes lower than 5 um wide, and moreover, for a larger epitaxial thickness. As is discussed, this dependence is connected with elastic relaxation at the edges of the SiGe epilayers.