Macro-particle reduction mechanism in biased arc ion plating of TiN

The mechanism of macro-particles (MPs) contamination in arc ion plating is investigated on TiN films under different biases. The effect of the biases is analyzed from the viewpoint of plasma physics. It is shown that the negatively charged MPs are affected by the biases through a repulsive force from the negatively biased substrate. They are more easily charged by electrons under pulsed biases because they repeatedly move in and out of the oscillating plasma sheath. In d.c. bias modes, the plasma sheath is stable and its charging effect is weak. Thus the repulsive force from the substrate under the pulsed biases is higher than that under the d.c. ones, and therefore, MPs are significantly reduced.