Influence of an electrical field on the macroparticle size distribution in a vacuum arc

The results of experimental study of macroparticle distribution in a vacuum are presented for Cu, Ti, Zr, and Cr cathodes. We have studied the macroparticle contamination of the films deposited on the substrate having floating potential and biased up to -1000 V with respect to the anode. It has been found that the macroparticle number significantly decreases (by a factor of 3-4) with substrate biasing for all examined cathode materials. A model of macroparticle motion in the quasineutral plasma and near-substrate sheath was proposed. The model bases on analyses of the macroparticle charging and motion in the quasineutral plasma and near substrate sheath. The model can qualitatively explain the macroparticle reduction in the coating due to negatively charged macroparticle reflection in an electric field. (C) 1999 American Vacuum Society. [S0734-2101(99)04805-8].