SIMS depth profiling of TiOxNy films

Amorphous TiOxNy films of varying stoichiometry have been deposited on Si a nd Cu substrates using ion-assisted deposition (IAD), The structure of the films and the effects of annealing in the 200-450 degrees C range have been examined, Secondary ion mass spectrometry (SIMS) has been used to investigate the nea r surface and the buried film/substrate interface. The Cs+ adduct approach has proved well suited to the depth profiling of these films, and provides a good test of the degree to which some of the common problems associated w ith SIMS depth profiles can be mitigated. Work function corrections based o n the Cs+ yield have been used to refine further the MCs+ intensities and r esolve structure, particularly at the film/metal interface. Under most expe rimental conditions for these films, the knock-on effect is observed to dis tort profiles by more than the matrix effects on ion yields. Profiles reveal a complex degradation mechanism, which is somewhat contradi ctory to that reported in the previous literature. The suggested mechanism of Cu migration through the film driven by oxide formation at the outer sur face, is operative only at elevated temperatures approaching complete break down of the films. In the operational range up to similar to 350 degrees C, Cu is observed to migrate through the film to the outer surface, however a nitrogen-rich layer is observed overlying a thin oxide zone and a largely intact TiON film. Copyright (C) 1999 John Whey & Sons, Ltd.