Carbon Nitride and Carbon Fluoride Thin Films Prepared by HiPIMS

Sammanfattning: The present thesis focuses on carbon based thin films prepared by high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS). Carbon nitride (CNx: 0 < x < 0.20) as well as carbon fluoride (CFx: 0.16 < x < 0.35) thin films were synthesized in an industrial deposition chamber by reactive magnetron sputtering of graphite in Ne/N2, Ar/N2, Kr/N2, Ar/CF4, and Ar/C4F8 ambients. In order to increase the understanding of the deposition processes of C in the corresponding reactive gas mixture plasmas, ion mass spectroscopy was carried out. A detailed evaluation of target current and target voltage waveforms was performed when graphite was sputtered in HiPIMS mode. First principle calculations targeting the growth of CFx thin films revealed most probable film forming species as well as CFx film structure defining defects. In order to set different process parameters into relation with thin film properties, the synthesized carbon based thin films were characterized with regards to their chemical composition, chemical bonding, and microstructure. A further aspect was the thin film characterization for possible applications. For this, mainly nanoindentation and contact angle measurements were performed. Theoretical calculations and the results from the characterization of the deposition processes were successfully related to the thin film properties.The reactive graphite/N2/inert gas HiPIMS discharge yielded high ion energies as well as elevated C+ and N+ abundances. Under such conditions, amorphous CNx thin films with hardnesses of up to 40 GPa were deposited. Elastic, fullerene like CNx thin films, on the other hand, were deposited at increased substrate temperatures in HiPIMS discharges exhibiting moderate ion energies. Here, a pulse assisted chemical sputtering at the target and the substrate was found to support the formation of a fullerene-like microstructure.CFx thin films were found to have surface energies equivalent to super-hydrophobic materials for x > 0.26 while such films were polymeric in nature accounting for hardnesses below 1 GPa. Whereas, an amorphous structure for carbon-based films with fluorine contents ranging between 16 % and 23 % was observed. For those films, the hardness increased with decreasing fluorine content and ranged between 16 GPa and 4 GPa. The HiPIMS process in fluorinecontaining atmosphere was found to be a powerful tool in order to change the surface properties of carbon based thin films.