DIELECTRIC FUNCTION SPECTRA OF STAINED AND RELAXED SI(1-X)GE(X) ALLOYS (X=0-0.25)

Dielectric function spectra for strained and relaxed Si1-xGex alloys w ith x-0.13 and 0.20 are presented in numerical form. The effect of str ain is shown to cause a modification of the spectra in the E1 critical point region, resulting in a decrease in refractive index at 1.96 eV, amounting to 0.06 at x=0.22. The spectral dependence of the refractiv e index is presented for a series of strained layers. An overview is g iven of spectral databases and the single-wavelength ellipsometry data available in the literature.