The "Sopra GES-5" is a spectroscopic ellipsometer. This sophisticated optical measurement equipment allows the analysis of layer thickness and layer sequence of several stacked layers of Material. Thickness measurement is possible with a sub-Angstroem (< 0.1nm) accuracy. By spectroscopic analysis also optical parameters such as dielectric constant or absorption coefficient may be determined in a spectral rang from ultraviolett (210 nm) to near infrared (2 µm). The "ultra small spot" option is an optional lens and mirror system that facilitates focusing the beam down to a 120 x 150 µm area. This option is particularly useful for analysis of microstructured systems.