Ion current extracted from a self ignition plasma around the target immersed in a pulsed rf ICP methane plasma

When a pulsed voltage is applied to a target immersed in plasma, the surrounding medium of the target is self-ignited under an appropriate discharge condition. For a three-dimensional substrate, ion implantation and deposition of the plasma species are promising to be uniformly attained by the self-ignition plasma. A retained dose of conformal ion implantation may increase with the self-ignition plasma generated in the target-immersed plasma. Ion are extracted from both the target-immersed plasma and the self-ignition plasma. In this research, a stainless steel target with a diameter of 140 mm and a thickness of 18 mm was immersed in a pulsed inductively coupled methane plasma to which a pulse voltage of −400 V to −10 kV with a width of 12 μs was repeatedly applied. The self-ignition plasma was generated at the voltage higher than about −1.2 kV. It was found that the shape of the current waveform changes by varying the applied voltage due to the change of the current from the self-ignition plasma.