Optical properties of titanium containing amorphous hydrogenated carbon films (a-C:H/Ti)

Titanium containing amorphous hydrogenated carbon films have been deposited by reactive magnetron sputtering. Real time laser reflectometry and ex situ spectrophotometry have served as a means for the determination of the optical constants index of refraction n and extinction coefficient k. The experimental results are being compared to effective medium theories, modeling the optical constants of the composite material from the ones of amorphous hydrogenated carbon and TiC. We have used the effective medium theories to estimate the bulk stoichiometries which agree with Rutherford backscattering experiments but deviate from the surface stoichiometries determined by in situ photoelectron spectroscopy. These deviations can be explained by surface diffusion and three dimensional cluster growth.