Effects of nitrogen flow rates on the growth morphology of TiAlN films prepared by an rf-reactive sputtering technique

Over the last decade titanium aluminum nitride (TiAlN) has been under active investigation as a promising alternative to binary coating materials for cutting and forming tools because of its superior oxidation resistance and lower thermal conductivity. However, the effects of nitrogen flow rates on the reactive sputtering of TiAlN films remain relatively untapped despite their importance in studying the growth morphology to acquire valuable knowledge for the selection of optimum coating conditions. In this paper we report the results of our study regarding the implications of nitrogen flow rate on the growth morphology of the TiAlN films reactively sputtered from a stoichiometric target of TiAl. Scanning and transmission microscopy (SEM, TEM), X-ray diffraction (XRD) and atomic force microscopy (AFM) have been used for film characterization, the latter of which is yet to be fully exploited as a tool for analyzing the effects of N 2 as a sputtering parameter.