TaNTa as an effective diffusion barrier for direct contact of copper and nisi

摘要

In this letter, the bi-layered structure of TaNTa is revealed to be an effective diffusion barrier for copper (Cu)NiSi direct contact application. Comparing with the conventional CuTaTaNNiSi contact structure, the proposed CuTaNTaNiSi contact structure can significantly increase the contact failure temperature over 100°C. It is demonstrated that the NiSi morphological stability is effectively enhanced by Ta capping, which is crucial to improve the performance of CuTaNTaNiSi contact. For TaNTa diffusion barrier, the Cu diffusion through TaNTa layers is revealed to be a diffusion-controlled process with an activation energy of 0.95 eV.