MODELING THE OPTICAL-RESPONSE OF SURFACES MEASURED BY SPECTROSCOPIC ELLIPSOMETRY - APPLICATION TO SI AND GE

We present a convenient formula for interpreting the surface contribution to ellipsometric measurements, which should facilitate the further development of such optical studies. The formalism has been generalized to allow for optical anisotropy at the surface. This generalized form allows direct comparison to theoretical models of surface optical response. The method is used to analyze measurements of the Ge(111)(2 x 1), Si(111)(2 x 1) and Si(100)(2 x 1) reconstructed surfaces. The results are compared to previously published results. We conclude that surface state transitions do not dominate the surface contributions above the bulk energy gap.