Dependence of diffusion barrier properties in microstructure of reactively sputtered TiN films in Al alloy/TiN/Ti/Si system

We have been investigated the diffusion barrier properties of the reactively sputtered titanium nitride (TIN) in Al-lwt%Si-O.Swt%Cu/TiN/Ti/Si system. The lower dense but N-rich TiN film was easy to react with the Al, showing the poor diffusion barrier properties. By means of plan-view TEM, lots of disorder regions and vacancies in the TiN film could be observed. We conclude that the rearrangement in the lower dense films is easier to occur by thermal treatment, giving rise to diffusion of Ti atoms, even if the TiN is N-rich film. This conclusion indeed implies the dense degree of the TiN film in atomic level has a significant effect on the reaction between the TIN and the Al, or the diffusion barrier properties.