Element composition and electrochemical behaviour of polycrystalline AlN thin films

Aluminium nitride (AlN) thin films were deposited under different nitrogen partial and total pressures by means of reactive d.c. magnetron sputtering. The investigated films had polycrystalline structure, revealed by electron beam diffraction (EBD). The depth profiles of Al, N and C distributions were registered by a direct emission layer-by-layer analysis in a hollow cathode glow discharge. All data indicated that there are no peculiarities of the element depth profiles in our films. The X-ray photoelectron spectroscopy (XPS) spectrum was used to determine the composition of the films. The spectrum clearly showed peaks from Al, N, O and C atoms present in the films. The electrochemical behaviour of the films was investigated using a d.c. electrochemical test in a 3% NaCl solution. The AlN films grown at a higher nitrogen partial pressure performed with a better electrochemical behaviour. A strong IR absorption band was obtained around 670 cm−1, which confirmed that the deposited films were AlN.