DIAMOND-LIKE CARBON-FILM PRODUCED BY VACUUM-ARC DEPOSITION TECHNIQUE AND ITS SURFACE APPEARANCE

Diamond-like carbon (DLC) films are deposited in a dc vacuum arc plasma with a graphite cathode. The arc current, the flow rate of hydrogen gas and the pressure are 50 A, 10 ml/min and 0.05 Pa, respectively. The substrate materials are Si (111), soda-glass and Mo. Process parameters are deposition time (3 to 30 min). The films are analyzed by laser Raman spectroscopy and the surface appearance of the films are observed with an optical microscope. The results are as follows: (1) the films deposited under these conditions have diamond-like carbon structure; (2) the films deposited for 3 min on Si or Mo and for 5 min on glass, wrinkle on the substrates; (3) the films deposited for more than 10 min on Si and for more than 15 min on glass, crack and flake off the substrates; and (4) the films deposited for more than 10 min on Mo, plainly stick on the substrate without any wrinkles or flakes. It is found that plain DLC films are able to be produced by the vacuum arc deposition method if the deposition time is selected appropriately, while never by the conventional plasma CVD method.