Industrial Application of Pulsed Dc Bias Power Supplies in Closed Field Unbalanced Magnetron Sputter Ion Plating

Pulsed dc power supplies are now commonly used in the reactive magnetron deposition of dielectric coatings from conductive or partially conductive sputtering targets. Their advantages, particularly the elimination of arcing and enhanced process stability are well recognised. In comparison, the application of pulsed dc power to the biasing of substrates in ion plating processes has received much less attention. The present study draws on experience with a range of pulsed dc bias supplies in industrial coating equipment, exploiting closed field unbalanced magnetron sputtering technology. Pulsed plasma characteristics have an impact on all stages of the coating process, from initial surface cleaning through to interface formation and the coating of components, requiring the appropriate selection of pulsing parameters. The synergistic interaction of pulsed dc bias, dc and pulsed dc closed field magnetron sources is explored. Practical considerations, such as the processing of thermally sensitive materials and the preservation of critical surface characteristics, are also discussed. SE/517