Novel spatially coordinated in-situ Raman and nanoscale wear analysis of FCVA-deposited DLC film

A novel combined in-situ system, integrating Raman spectroscopy and depth-sensing techniques, was applied to analyze the wear induced transformation on the microstructure of diamond-like carbon (DLC) film deposited on Si substrates using a filtered cathodic arc vacuum (FCVA) deposition system. Using this synchronized characterization technique it was demonstrated that upon wear-induced removal of upper surface layers, the intensity ratio (ID/IG) for the area inside wear tracks decreases. On the other hand, while the peak position for the D line (PD) shifts to higher wavenumbers, the peak position for the G line (PG) shifts to lower wavenumbers. The coefficient of friction shows significant reduction upon increasing the depth of the wear tracks. These results confirm our previous preliminary report on the possible existence of layers rich in sp2 in the surface region. It was also shown that the wear debris is more graphitized.