generates argon plasma in the reactor as a result of the cleaning it was observed that the plasma current of each electrode became uniform soon after the initiation of the cleaning process before the cleaning process the plasma current had differences of about 0 2 a between the electrodes due to the different surface condition of the electrodes this kind of plasma behavior is possible because an independent power source was used for each electrode which minimizes the current differences between the electrodes caused by the impedance differences between the electrodes in the cleaning process a high frequency current of 1 a was applied to the electrode and the temperature of the electrodes did not exceed 100 u00b0 c after the cleaning process a diamond like carbon film is deposited by supplying pure methane gas to the synthesizing apparatus having multi pair electrodes depicted in fig2 the introduction of the methane gas can be performed at a rate ranging from 50 sccm to 500 sccm a power source having a frequency within the wide range of 100 khz to 10 mhz can be used as the high frequency current source at the same time the voltage applicable by the high frequency current source should exceed 200 v if impedance differences exist be compensated by adjusting the high frequency current sources which are connected to each electrode independently this compensation assures that the power applied to each electrode 11a do not exceed 1 kw the coating of carbon film is performed using the.