Study of TiN and Ti/TiN coatings produced by pulsed-arc discharge

TiN coatings on steel substrates and silicon (100), and Ti/TiN bilayers on silicon (100) are produced using vacuum arc processes by means of plasma-assisted techniques. These films are prepared by using a Ti and nitrogen gas target at 1.7 mbar for TiN films and argon at 1.3 mbar for Ti coatings. The system is composed of a vacuum chamber with two opposite electrodes upon which there is a 300-V discharge. The films obtained are characterized in composition by means of X-ray diffraction (XRD) techniques, observing a preferential orientation for TiN on a (200) plane. Moreover, the crystallite size and the lattice microstrain were calculated, showing random behaviors when the number of pulsed discharges is increased, due to the continuous processes of relaxation and formation of dislocations into the film. A morphological analysis was done using atomic force microscopy (AFM) techniques, observing an increase of roughness and grain size as a function of the number of pulsed discharges. Furthermore, approximate thicknesses of the films were calculated, obtaining values in the order of nanometers.