Comparative Study of Defects in Semiconductors by Electrolyte Electroreflectance and Spectroscopic Ellipsometry

It is shown that, because of the electrostriction and polarization of defects by the modulating electric field, electroreflectance spectra are more affected by defects than are third-derivative spectra from ellipsometry data. The theory of electroreflectance is generalized to include these effects. Plasticity and long-range strains are shown to lead to a first-derivative line shape and polarizable defects to a second-derivative line shape. For defect-rich samples these new terms dominate the usual third-derivative line shape.