Design and construction of bipolar pulsed-dc magnetron sputtering system for thin films synthesis.

Abstract

An asymmetric bipolar pulsed-dc magnetron sputtering system has been developed for thin films
synthesis. The system consists of a pulsed-dc power supply, an unbalanced circular planar magnetron sputtering gun supporting a two inch diameter target, and a vacuum system. A test with a copper target under argon atmosphere of 40 mtorr showed that the pulsed-dc magnetron argon plasma can be successfully generated with a cathode negative voltage between -500 to -600 volts and the reverse positive pulse of 0-120 volts. The pulse frequency was 17 kHz and the corresponding current density at the target surface was approximately in the range of 15-25 mA/cm2. These operating conditions could be applied for the preparation of Na_xCo₂O₄ thermoelectric thin films and other oxide compounds.