Enhanced diffusion barrier property of nanolayered NbMoTaW/TiVCr high entropy alloy for copper metallization

In this work, the single-layered amorphous NbMoTaW and multilayered amorphous NbMoTaW/TiVCr high entropy alloys were prepared to investigate the diffusion barrier performance. The microstructure and thermal stability of these samples were analyzed by X-ray diffraction, transmission electron microscope, and four-point probe method after annealing at different temperatures. In the single-layered structure, Cu silicide formed after annealing at 600 degrees C. The reason is that the amorphous NbMoTaW layer crystallizes during annealing, which causes the interdiffusion between Cu and Si through grain boundaries (GBs). However, the multilayered structure still maintains effective barrier performance as the annealing temperature is below 800 degrees C. Amorphous structure without GBs diffusion path, severe lattice distortion, and the high dense layer interface are responsible for the improved barrier property in the multilayered system. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, single-layered and multilayered amorphous high entropy alloys were prepared to investigate their diffusion barrier performance. It was found that the multilayered structure exhibited better barrier performance due to the absence of grain boundary diffusion path and severe lattice distortion in the amorphous structure.