Reflectance difference spectroscopy RDS/RAS combined with spectroscopic ellipsometry for a quantitative analysis of optically anisotropic materials

We discuss various aspects of the characterization of optically anisotropic materials by spectroscopic ellipsometry (SE) and reflectance-difference/anisotropy-spectroscopy (RDS/RAS). The main focus is on the limitation of quantitative analysis, and will be discussed in detail for two different examples: group-III-nitride layers and ZnO. We suggest that a combination of SE and RDS is a good choice to determine the 14 components of the dielectric tensor (here epsilon(vertical bar vertical bar),epsilon(perpendicular to)) and allows also to determine important parameters such as thickness or sample orientation.