Submicrometer Ultrananocrystalline Diamond Films Processed In Oxygen And Hydrogen Plasma And Analyzed By Uv-Vis Spectroscopy: Thickness And Optical Constant Results

Results of UV-vis spectroscopy (spectrophotometry) of highly conductive submicrometer nitrogen-incorporated ultrananocrystalline diamond, (N)UNCD, processed in technologically important oxygen and hydrogen plasmas are presented for the spectral range of 200-1200nm. The (N)UNCD films feature high contrast interference. As-grown and etched samples were analyzed using a simple practical analytical optics methodology that allowed for accurate evaluation of film thicknesses and (N)UNCD etching rates. The obtained results were cross-validated using scanning electron microscopy. Reflection simulations based on the Fresnel equations and using the optical constants of the Si substrate provided for evaluation of spectral dependencies of the refractive index and extinction coefficient of (N)UNCD. It was found that the presence of grain boundary sp(2) phase causes noticeable extinction (zero for diamond) and slightly changes the refractive index, making its behavior nonmonotonic.