Hollow cathode plasma activation in reactive gas atmosphere

A new magnetically enhanced hollow-cathode based plasma source was developed in order to generate a large volume homogeneous plasma for substrate pretreatment and plasmaactivated deposition processes. The hollow cathode plasma is characterized by various diagnostic techniques. Spatially resolved Langmuir probe and optical emission spectroscopy measurements reveal plasma densities of more than 1012 cm-3 and 1011 cm-3 at distances of 30 cm and 125 cm from the plasma source, respectively, and electron temperatures between 6 eV and 1 eV in pure argon atmosphere at pressures between 0.1 and 3.4 Pa. When operated in nitrogen, energy-dispersive mass spectrometry demonstrates that efficient ionization and dissociation of the molecules takes place. Stronger magnetic fields and lowered gas flows through the cathode tube result in enhanced ionization and dissociation rates and higher ion energies. The effect of hollow-cathode activation on reactively sputter deposited wear resistant ZrNbN coatings is shown, demonstrating significantly improved hardness and surfacemorphology