Generation of RF plasma assisted high power pulsed sputtering glow discharge without using a magnetic field

High power pulsed sputtering plasma is an emerging technology used to modify the surfaces of industrial components and biomedical parts. The characteristic feature of the plasma is that metallic species are highly ionized and charged particles are magnetized. In order to use the plasma source in a variety of material processing applications, it is desirable that the glow is generated without a magnetic field. In this paper, a sputtering of metallic species is enhanced by a pulsed dc voltage applied to a pair of electrodes immersed in an RF plasma. Sputtered metallic species are ionized as follows: first, a 200 kHz-RF (radio frequency, output voltage: 3 kV and duration: 200 mu s) argon plasma is generated. Then, a pulsed dc (direct current) voltage is applied to a pair of electrodes (of 60 mm diameter and 75 mm long) set in the RF plasma to accelerate argon ions toward the cathode (sputter target). The applied voltage ranges from 0.8 to 1.4 kV with negative polarity. The argon gas pressure is 2.7 Pa. The pulse width is 60 mu s. In a typical example, the induced current through the electrode is 45 A with a voltage of 1000 V. The instantaneous consumed power of 45 kW and the energy consumed per pulse is 2.7 J, corresponding to an average power of 216 W at a repetition rate of 80 Hz. (C) 2009 Elsevier B.V. All rights reserved.