Evaluation and modeling of the optical properties of molybdenum particles in ceramic/metal composites

The optical constants of thin sputtered molybdenum layers, embedded in a ceramic-metal composite, which was produced by a batch sputtering deposition system, were analyzed. This was done by assuming a multilayer system for a tin oxide-molybdenum cermet and calculating the optical constants from angular and polarization dependent reflection and transmission spectra. These optical constants were found to differ strongly from those for sputtered bulk material obtained ellipsometrically. Good agreement between measured effective refractive indices for cermets and effective medium calculation was found, if these optical constants for molybdenum were used in the effective medium calculations. Differences to the optical constants of the cermet determined ellipsometrically were explained by the birefringence of the cermet. The size and the shape of the embedded particles were investigated with an atomic force microscope.