Characterization of Different Length Scales and Periodicities inGe/Si Microstructures by Raman Spectroscopy: Theory and Experiment

The Raman spectra of samples of the type [(GemSi,,,)N-x Ge, Si,I x p with n w rn w 5 monolayers, M= 200 monolayers and p = 10-20 were measured in the backscattering configuration in the wavenumber range 2-600 cm-'. The experimental results are discussed by comparison with simulated spectra calculated with a linear chain model with bond polarizabilities for the Raman intensities. Comparison between experimental and theoretical spectra gives insights into the sensitivity of the different Raman peaks as a probe of periodicity and interface roughness length scales.