Stoichiometry of Ta–N Film and Its Application for Diffusion Barrier in the Al₃Ta/Ta–N/Si Contact System

In order to obtain a stable contact structure applicable to Si–LSI thin film technology, we have produced the contact structure of Al 3 Ta/Ta–N/Si by interposing the Ta–N film as a diffusion barrier between Al 3 Ta film and Si substrate. The contact structure was heat-treated at various temperatures in vacuum, and the behavior of mass transport across the interfaces of both Al 3 Ta/Ta–N and Ta–N/Si caused by the heating process was examined by Auger depth analysis. Also, on the basis of X-ray diffraction and XPS analysis, the barrier properties of the Ta–N film were examined with respect to the crystalline state and the chemical bonding state of the film. It is revealed that the thermal stability of this contact structure is closely related to the stoichiometry of the Ta–N film used as a diffusion barrier.