Chemical stability of TiN, TiAlN and AlN layers in aggressive SO 2 environments

In this paper, we have studied, using X‐ray photoelectron spectroscopy (XPS), the chemical stability of TiN, TiAlN and AlN layers produced by magnetron sputtering on Si wafer substrates, against humid, SO 2 ‐polluted atmospheres. The results have indicated that the TiN layers suffer almost no degradation after seven days of exposure to the aggressive environment. The degradation of the TiAlN layers is small, and this is evidenced by the appearance of signals corresponding to NO bonds in the N 1s spectra, after seven days of exposure to the corrosive atmosphere and the increase in the Ti 2p spectra of the contribution corresponding to TiO 2 . In contrast, the degradation experienced by the AlN layers is quite large. The spectra reveal dramatic changes after just one day of exposure to the aggressive conditions. This is related to the preferential growth of the AlN layers, which gives rise to an open, columnar structure.