Effect of Various CF4/CH4 Flow Ratios on Structure and Optical Band Gap of Fluorinated Diamond-Like Carbon Thin Films

Fluorinated diamond-like carbon (F-DLC) thin films are deposited using radio frequency plasma enhanced chemical vapor deposition under various gas flow ratios. The surface morphology of the F-DLC thin films deposited at lower gas flow ratios is a compact and uniform structure, and it became rough with the increase of gas flow ratios. The relative atomic contents of fluorine and chemical bonding configurations of C-Fx (x=1, 2, 3) in the thin films increases with the increase of gas flow ratios. The optical band gap of the thin films presents a decrease of different degree with the increase of gas flow ratios.