Characterization of plasma conditions in a hollow cathode arc evaporation device

The effective application of the hollow cathode arc (HCA) in plasma activated PVD processing is based on two properties: production of a high density plasma and generation of suprathermal beam electrons. This paper deals with investigations into the generation and the relaxation processes of beam electrons in an HCA device. The parameters of the electron component in the plasma were measured by a directionally resolved Langmuir probe and a magnetic spectrometer device. In the gases and gas mixtures used, three groups of electrons were detected near the cathode exit: isotropically distributed electrons, high energy and low energy beam electrons. The energy and concentration of these three groups depend on the gas mixture and pressure. From the results obtained, a model of electron beam generation inside a hollow cathode was developed. In relation to the deposition conditions, the electron temperature and electron density were measured near the substrate too. The results obtained are discussed with regard to the optimization of an HCA deposition device.