Phase transitions in vacuum arcs in the context of liquid metal arc sources

Arc sources using liquid cathode material could enable very high rate deposition of metal and metal compounds of cathode materials of low melting point. Of special interest are cathodes of zinc, cadmium, tin, and indium as they can be used to deposit high quality transparent conducting oxide films. Phase transitions are briefly reviewed using phase diagrams and vapor pressure curves, and preliminary experiments are reported using a crucible designed to hold the solid or liquid cathode material. Liquid zinc showed evidence of boiling, and liquid tin emitted less and smaller macroparticles than the same source using solid tin.