Normal incidence ellipsometry has been used to measure the change in the complex anisotropic reflectance ratio ¿ upon oxidation of the clean Si(110)16 × 2 surface. The spectroscopic change in the amplitude of ¿ (tan(¿)) shows a broad maximum of height 1.4 × 10¿3 in the high energy region above 2.5 eV. No phase shift difference for the reflectance coefficients belonging to the surface principal optical axes has been measured. A Kramers-Kronig transformation of the amplitude ratio showed that a change in the phase is not expected. The change in tan(¿) indicates that the change in reflection upon oxidation in the optical region ismainly in the (10) direction.
Wormeester, H., Molenbroek, A. M., Wijers, C. M. J., & van Silfhout, A. (1992). "Change of the surface induced optical anisotropy of the clean Si(110) surface by oxidation". Surface science, 260(1-3), 31-36. https://doi.org/10.1016/0039-6028(92)90015-X