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 Al3Ta/Ta–N/Si by interposing the Ta–N film as a diffusion barrier between Al3Ta 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 Al3Ta/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. © 1990 The Japan Society of Applied Physics.