Spectroscopic ellipsometry is a non-destructive, noncontact, and non-invasive optical technique which is based on the change in the polarization state of light as it is reflected obliquely from a thin film sample. Ellipsometry uses a modelbased approach to determine thin film, interface, and surface roughness thicknesses, as well as optical properties (and much more!) for thin films ranging in thickness from a few A to several tens of microns. Select