Texture-related roughness of (Nb,Ti)N sputter-deposited films

We study the properties of (Nb,Ti)N films deposited by reactive magnetron sputtering in an atmosphere of argon and nitrogen at ambient substrate temperature, focusing, in particular, on the technological factors determining film texture and roughness. We find that increasing the adatom energy, while keeping the film chemical composition constant, results in a change of texture from [111] to [100]. Similar changes in film texture are observed as the nitrogen injection decreases for a constant sputtering pressure, indicating that adatom energy is not the only one determining factor. Analyzing the experimental data, it is concluded that nitrogen concentration has a very strong influence on the process of the texture formation, since an increase in nitrogen injection results in an increase in adatom energy, while the film growth is driven toward [111] texturing. Film roughness is strongly related with texture in both experiments, i.e., decreases with an increase in the ratio of [200] and [111] XRD line intensities, indicating that film roughness is determined by crystal habit.