Spectroscopic Ellipsometry: Multilayer and porous structures

Due to its non-destructive nature, spectroscopic ellipsometry has become commonplace in the semiconductor industry as a widely used thin film characterization technique. This model dependent technique exploits polarization states of light to study the structures and compositions of thin films ranging in thickness from just a few angstroms to several microns. In this study, three multi-layered MBE-grown thin film stacks were characterized over a spectral range of 2.0-5.0eV along with the irregular structures of a series of stain-etched porous silicon thin film layers. By using a novel modeling technique, the pore size and distribution was determined and correlated with surface resistivity and Raman measurements of the same structures.