Plasma transport in a new cathodic arc ion source, theory and experiment

The ever increasing demand for coatings of higher and higher quality requires the development of new methods for producing them. One of the promising new avenues involves the use of arc-produced plasmas. The principal advantage for such methods is that the plasma ions can be controlled through the use of applied electromagnetic fields, so that the energy with which the coating material arrives at the substrate can be regulated. The primary disadvantage is ridding the plasma beam of the macroparticles which are produced simultaneously with the beam. One approach to overcoming this difficulty is to pass the plasma through a magnetic filter. The large mass of the macroparticles prevents them from bending in the filter, while the plasma is directed to the substrate. The authors have developed a new macroparticle-filtered metal ion source, based on the cathodic arc, which makes use of steered arc control technology. The ion currents and electrical potentials in this source were measured at various locations and used to assess a simple computer model. The implications of this assessment for future arc source design is discussed.