On the macroparticle flux from vacuum arc cathode spots

The macroparticle contamination of vacuum-arc-deposited thin films generated by a plasma source with an optional axial magnetic field is studied. Emphasis is placed on the macroparticle flux near the discharge axis. The arc current, metal species, deposition system geometry and axial magnetic field strength are varied. Distribution functions for macroparticles of Pb, Ag, Cu, Pt, W, and Ni are determined, normalized to the film thickness deposited or the charge transferred. The application of the axial magnetic field leads to a considerable reduction of the normalized macroparticle flux since the plasma is effectively focused by the field, whereas the macroparticle production is not influenced. The macroparticle content normalized to the deposited film thickness is reduced to about 20-35% of that without an additional magnetic field