Wear life evaluation of diamond-like carbon films deposited by microwave plasma-enhanced CVD and RF plasma-enhanced CVD method

Diamond-like carbon (DLC) films were prepared by microwave plasma-enhanced chemical vapor deposition (MW PECVD) and by radio frequency plasma-enhanced chemical vapor deposition (RF PECVD) method. In case of the DLC films deposited by the MW PECVD, a negative DC bias (−375 to −550 V) was applied to enhance the adhesion between the film and a Si (silicon) substrate. The Raman spectroscopy suggested the DLC films were amorphous. AFM images show that the surface roughness of the films decreases with increasing negative DC bias voltage. In case of the DLC films deposited by the RF PECVD, AFM images show that the surface roughness of the DLC films decreases with increasing the RF power (25–200 W). In this study, the wear life of the DLC films deposited by both deposition methods was more affected by surface roughness and coating thickness than by structural details revealed by the Raman works.