STRUCTURE AND MECHANICAL-PROPERTIES OF A-C-H FILMS DEPOSITED ONTO POLYMER SUBSTRATES

Semi-transparent amorphous hydrogenated carbon films were deposited on to a polymer (polyethyleneterephthalate) substrate by means of plasma decomposition of butane. The effects of pressure and discharge current on the nanohardness, residual stress, adhesion and wear resistance of the films were studied. IR spectroscopy and electron paramagnetic res onance were used for structural characterization of the films. The nan ohardness and wear resistance were found to increase with decreasing p ressure. However, on decreasing the pressure one can also observe high er residual stress and absorption, lower adhesion and slower growth ra te. The films deposited at lower pressures (3-4 Torr) exhibit lower C= O, CH and OH contents and a larger amount of broken bonds. The CH2-to- CH3 ratio varies only slightly with the chamber pressure. The influenc e of the discharge current was also studied. It was found that an incr ease in discharge current results in higher hardness and wear resistan ce but causes a larger residual stress and darkening of the films.