In-situ dual-wavelength and ex-situ spectroscopic ellipsometry studies of strained SiGe epitaxial layers and multi-quantum well structures

Abstract

In-situ dual-wavelength ellipsometry and ex-situ spectroscopic ellipsometry have been used to study strained Si 1−x Ge x Si multilayers. Reference dielectric function spectra of strained Si 1− x Ge x with 0.06 < x < 0.29 have been obtained for the first time and an interpolation procedure based on the strain dependence of the dominant critical point energies developed. Good agreement with composition and thickness values from corroborative techniques was obtained when the effects of strain were taken into account.