Effect of stress and composition on the Raman spectra of etch-stop SiGeB layers

Abstract

Si1−(x+y)GexBy strained layers on Si (x≤3.4%, y≤0.4%) have been analyzed by Raman spectroscopy. Stress in the layers has not been observed to affect the Fano interaction parameters of the first‐order Si–Si Raman line. These parameters have been determined in the range of B concentrations from 5×1019 to 2×1020 cm−3 and Ge fractions from 1% to 3.4%. The observed shift in the spectra has been found to depend linearly on both the germanium and boron contents. These data have been correlated with the stress measured in the layers by mechanical wafer bow measurements. The dependence of the Raman shift on the germanium content and strain agrees with that previously reported for strained SiGe layers. According to these data, Raman spectroscopy appears as an interesting tool for the nondestructive assessment of stress and composition of these layers.