Characterization of a Ti vacuum arc and the structure of deposited Ti and TiN films

Abstract
The energy of Ti neutrals and Ti+ ions was determined in the region of the cathode spot of a Ti vacuum arc by measurement of the Doppler broadened profiles of Ti(I) and Ti(II) emission lines using Fabry-Perot interferometry. Energy analysis of Ti+ and Ti++ was carried out at a distance from the cathode using an electrostatic analyzer. The emission lines showed that the neutrals had energies corresponding to approximately 0.4 eV while the Ti+ ions had a most probable energy of 3 eV. The energy analyzer showed that remote from the cathode spot Ti+ had a most probable energy of 80 eV. This large difference is explained in terms of a simple model for the arc which includes a potential ‘‘hump’’ near the cathode. The charge fraction of the evaporant was measured to be approximately 0.5, and the effect of nitrogen background gas on the energy distribution was observed. Deposited films of Ti and TiN were prepared and the influence of substrate bias investigated. It was found that under high negative bias the Ti films exhibited a preferred 〈110〉 orientation consistent with previous studies of ion-beam-induced textures.