OPTICAL-EMISSIONS DURING PLASMA-ASSISTED CHEMICAL-VAPOR-DEPOSITION OFDIAMOND-LIKE CARBON-FILMS

The deposition of diamond-like carbon (DLC) films onto silicon wafers and polyethyleneterephthalate (PET) from methane-hydrogen gas mixtures by plasma assisted chemical vapor deposition was investigated by opti cal emission spectroscopy. Film growth rates, crack formation, and ave rage electron energy in the plasma were analyzed for various depositio n conditions. The cracks in the DLC films deposited onto PET could be removed by increasing the hydrogen content in the gas mixture. No adju stment of ion energy, substrate temperature control, or addition of in ert gas was necessary to avoid crack formation. In the commonly used r ange of bias voltage above 500 V, the intensity of the H alpha line (6 56.3 nm) correlated well with the film deposition rate. The hydrogen p eak intensity can be used for on-line, non-contact, instantaneous moni toring of the deposition rate.