Growth and characterization of carbon nitride(x) thin films

The present research demonstrated that carbon nitride (CN{dollar}rmsb x){dollar} thin films can be synthesized using dc reactive magnetron sputtering. The resulting films were smooth, and electrically semi-insulating, and were primarily amorphous with a small volume fraction of nanocrystallites. The films had nitrogen-to-carbon ratios {dollar}sim{dollar}0.4-0.8 depending on deposition conditions. Results from Auger peak shape and Raman analysis suggested the presence of sp{dollar}sp3{dollar} bonded carbon. Indications of sp{dollar}sp2{dollar} bonded carbon and sp{dollar}sp2{dollar} bonded nitrogen were observed from electron energy loss analysis. Carbon-nitrogen stretching vibrations were clearly seen in IR and Raman spectra (sp bonded carbon). Nitrogen (1s) XPS results also indicated that nitrogen incorporation in CN{dollar}rmsb x{dollar} films was in the forms of carbon-nitrogen bonds.; Carbon nitride thin films showed thermal stability up to 750{dollar}spcirc{dollar}C in vacuum with microstructure and composition unchanged. Hardness value representative of the amorphous matrix was comparable to that of amorphous carbon films. Large elastic recovery at low load and high yield strength were both observed for these films, making them potential candidates for protective applications which operate below 4-6 GPa. They also exhibited excellent adherence and low coefficient of friction (COF) under unlubricated and lubricated conditions. The corresponding COF was {dollar}sim{dollar}0.15-0.25 and {dollar}sim{dollar}0.03 for block-on-ring tribotests. The dominant wear mechanism was found to depend on the size of the wear debris and how adherent the film was attached to the substrate. Ball-on-disc tribotests under different environments showed the importance of moisture on the friction behaviors of CN{dollar}rmsb x{dollar} films. Lower COF and lower wear rate were observed with increasing humidity. This was explained in terms of smaller size of oxide wear debris instead of large metal particles for lab air and humid nitrogen test environments.; Variations in deposition conditions were found to strongly influence film properties. Subtle changes of Raman features of CN{dollar}rmsb x{dollar} films in the 1300-1600 cm{dollar}sp{lcub}-1{rcub}{dollar} range as a function of deposition conditions were correlated to the extent of structural disorder in these films. The increase in disorder was attributed to enhanced energetic particle bombardments while better momentum transfer was responsible for less structural disorder.