Influence of reactive gas on ion energy distributions in filtered cathodic vacuum arcs

The energy with which depositing species impinge on a growth surface is one of the main factors influencing the microstructure and properties of the thin films fabricated in plasma deposition processes. In this letter, we examine the effects of a variety of deposition parameters on the ion energy distribution beyond the magnetic filter in a filtered cathodic vacuum arc (FCVA). The results indicate that the ion energy distributions do not vary significantly with the magnetic field strength, magnetic field configuration, lateral position in the beam, or bias on the filter duct wall in the ranges studied. The energy distribution was however strongly affected by the presence of a reactive background gas. A reduction of 10 eV was recorded for a background pressure of 10^-3 Torr of N₂ gas in a carbon FCVA. This result has implications for all FCVA depositions carried out in a gas atmosphere and is consistent with the view that ion transport in the magnetic filter occurs due to an electrostatic guiding potential well.