Structure and properties of fluorine and boron co-alloyed diamond-like carbon films

Fluorine (F) and boron (B) co-alloyed diamond-like carbon (FB-DLC) films were prepared on polymethyl methacrylate (PMMA), polycarbonate, glass, silicon (100) and Mo sheets by the plasma immersion ion processing (PIIP) technique. A pulse glow discharge plasma was used for the PIIP deposition and was produced at a pressure of 1.33 Pa from acetylene (C2H2), diborane (B2H6), and hexafluoroethane (C2F6) gas. The composition of FB-DLC films was measured by using the ion beam analysis techniques, and the bonding structure was characterized by IR and Raman spectroscopies. The co-alloying of F and B into DLC films resulted in the formation of F-C and B-C hybridized bonding structures. The levels of the F and B concentrations affected the composition, chemical bonding and properties as was evident from the changes observed in hydrogen concentration, optical gap energy, hardness, friction coefficient, and contact angle of water on films. Compared to B-alloyed or F-alloyed DLC films, the F and B co-alloyed DLC films exhibited a reduced hydrogen concentration, high hardness and optical gap energy, and improved hydrophobic and tribological properties.