Strain and composition in self-assembled SiGe islands by Raman spectroscopy

We have investigated self-assembled Si1-xGex islands grown on Si (001). We show that the average composition and both the epsilon(xx) and epsilon(zz) average strain components can be derived from Raman scattering spectra. Both nm-sized and mum-sized islands are investigated. The experimental results are compared successfully with finite-element strain simulations. Raman scattering is shown to be a versatile and reliable tool for investigating capped and uncapped islands. It is shown that strain profiles in mum-sized islands can be obtained by means of micro-Raman. (C) 2002 American Institute of Physics.