The present invention relates to implementation of magnetic and electrostatic forces to guide ions along curved trajectories in an ion source such that macroparticles are separated from the ion stream. Magnetic and electrostatic fields act in concert with the present invention to cause ions to flow along curved trajectories from the arc source to an area where workpieces may be treated. Since macroparticles produced by consumable electrode sources are much less affected by magnetic and electrostatic fields, said macroparticles are able to be separated from the ion stream due to the curved trajectories followed by the ions. The present invention permits effective macroparticle filtering by incorporating a consumable electrode material that faces away from the workpieces and to a closed end of the ion source. This filtering technique allows separation of macroparticles from the ion stream without substantially compromising deposition area, deposition rate, ion transport efficiency and/or uniformity in coating.
An apparatus for generating plasma includes a cathode having an evaporable surface configured to emit a material comprising plasma and macroparticles; oppositely directed output apertures configured to direct the plasma; a filter configured to transmit at least some of the plasma to the output apertures while preventing transmission of at least some of the macroparticles, the filter comprising at least one deflection electrode disposed generally parallel to and facing at least a portion of the evaporable surface; a first element for generating a first magnetic field component having a first polarity between the cathode and the at least one deflection electrode; and a second element for generating a second magnetic field component having a second polarity at the evaporable surface of the cathode that is opposite that of the first polarity such that a low-field region is created between the evaporable surface and the at least one deflection electrode.
