Unusual Cathode Erosion Patterns Observed for Steered Arc Sources

A cathodic arc source with a magnetron-type magnetic field was investigated for stability, erosion, and compatibility with a linear macroparticle filter. Cathodic arc spot and plasma distributions were photographed during the transition from a pure argon background (0.5 Pa) to a mixture of argon and oxygen. We report about unusual cathode erosion patterns, which were narrow (~2 mm) with periodic pits when operating in argon, and broad (~10 mm) with periodic groves and ridges when operating in argon and oxygen mixtures.