NITROGEN FLOW RATE DEPENDENCE OF THE GROWTH MORPHOLOGY OF TiAlN FILMS DEPOSITED BY REACTIVE SPUTTERING

초록

In this paper we report the results of our study on the implications of nitrogen on the growth morphology of the reactively sputtered TiAlN films from stoichiometric target of TiAl. The films deposited in this technique are preferably (200) oriented of NaCl structure of TiN. However, at lower nitrogen flow rates the X-ray diffraction (XRD) peak of (200) phase decrease in intensity and broadens as an additional peak of (1011) wurtzite-structure alloys overlap at the same 2q value. From scanning and transmission electron microscopy (SEM and TEM) analysis it was found that the film growth takes place according to the columnar morphology. With increase in N2 flow columns become denser. TEM selected area diffractograms show the presence of dominant single crystal phase in a polycrystalline state. Atomic force microscopy (AFM) indicates a fluctuating surface morphology mainly arising out of the grain domains distribution in random fashion. Surface roughness was found to be tending to a constant value at higher nitrogen flow rates. Bearing ratio has also been plotted as a function of height, taking the maximum depth probed by the AFM tip as height zero.