Spectroscopic ellipsometry studies of heteroepitaxially grown cubic silicon carbide layers on silicon

Cubic silicon carbide (3C-SiC) films grown heteroepitaxially on silicon by solid source molecular beam epitaxy are investigated by variable angle spectroscopic ellipsometry. It is demonstrated that data analysis on the basis of a three-layer-model combined with effective medium approximation for the dielectric functions yields parameters which characterize surface roughness, the non-ideal substrate/film interface and possible Si excess. A comparison of these results with studies performed by atomic force microscopy, Auger electron spectroscopy, and transmission electron microscopy emphasizes the reliability of the optically determined data. The optical constants of 3C-SiC used for the simulation of the layer structure are determined by means of a CVD grown sample.