Ion-assisted sputtering of TiN films

Abstract

Ion bombardment of growing films is one of the possible ways to produce films with specific properties. As yet there are no general rules for the production of these films. The quality of TiN films produced depends on the deposition conditions. A sharp transition from porous, black TiN films to compact, dense, bright gold TiN films is observed at a substrate bias U s of about -40 V. Recent experiments have indicated that the microstructure of TiN films and the transition mentioned above can be controlled by the ion energy delivered to the growing film per deposited particle E p = eU s v i/ v m. This paper investigates the transition from porous, soft TiN films with a zone I microstructure to compact, hard TiN films with a zone T microstructure as a function of i s, U s and the deposition rate a D at constant temperature T s = 350 °C and pressure p T = 5 Pa. Correlations between the microhardness HV, the macrostress σ, the microstrain e, the lattice parameters, the intensities of the X-ray reflections and the colour and appearance of the film are discussed. The zone I to zone T transition is observed at E p ≈ 150 eV atom -1.