Comparative study of c-axis AIN films sputtered on metallic surfaces

We have investigated the crystal quality, the residual stress and the composition of AIN thin films with{00 center dot 2} preferred orientation sputtered on metallic surfaces (Al0.9Si0.1, Cr, Mo and Ti) and, for comparison, on oxidized Si wafers. The AIN films deposited on metallic surfaces showed values of strain and residual stress significantly lower than on the oxidized Si wafers. The AIN films with the best crystal quality were achieved on Mo, with grain sizes ranging from 20 nm to 60 nm. In the case of AIN sputtered on Al0.9Si0.1, substrates, an unexpected behavior was observed, consisting in the reaction between the A1 substrate and the nitrogen from the plasma to form stoichiomictric AIN. For the AIN films deposited on Ti, we found that a large concentration of nitrogen (up to 10%) had been incorporated into the Ti layer, although we did not observe the formation of TiNx polytypes. No chemical reactions were observed for the AIN films sputtered on Cr and Mo substrates. (c) 2004 Elsevier B.V. All rights reserved.