Atomic-scale structural evolution of Ta-Ni-Si amorphous metal thin films

To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/materials-letters/We investigated the thermal stability of a new ternary amorphous metal thin film, Ta₂.₄Ni₂.₂Si, and assessed its suitability as a Cu diffusion barrier for semiconductor device applications. Transmission electron microscopy was coupled with atom probe tomography to provide a detailed understanding of the atomic-scale evolution of both structure and composition as a function of annealing temperature. We show that the amorphous structure is stable up to >800 °C under ultrahigh vacuum, while annealing to 900 °C induces nano-crystallization of a single ternary phase in an amorphous matrix. The implications of crystallization and solute partitioning are examined in the context of high-temperature stability to aid in the design and understanding of this new class of thin film materials