Raman spectroscopy is used to characterize the microscopic bond structure of Si1−x−yGexCyalloys epitaxially grown on Si substrates by C implantation into Si1−xGexepilayers and subsequent annealing. The Ge and C concentrations in these alloys can be chosen so that its average lattice constant equals the lattice constant of Si. Our Raman results suggest that in these strain‐compensated alloys the Si–Si bonds are not identical to those in bulk Si but experience a considerable local deformation. ©1995 American Institute of Physics.