In this paper, we demonstrate a thin film Cu-Ni-Nb alloy deposited directly on silicon, without a designated barrier, showing very high thermal stability at a temperature up to 700 °C for 1 h. Thin [Nb-Ni12]Cux films were sputter deposited and annealed, and their material and electrical properties were studied. The results can be explained by the “cluster-plus-glue atom” model for stable solid solutions, where [Nb-Ni12] cuboctahedral clusters are embedded in a Cu matrix. In this model, the clusters are congruent with the Cu minimizing atomic interactions allowing a good stability. The properties of the films were found to be affected by the Ni/Nb ratios. Especially, the (Nb1.2/13.2Ni12/13.2)0.3Cu99.7 film annealed at 500 °C for 1 h had the lowest electrical resistivity of about 2.7 μΩ cm. And even after 40 h annealing at 500 °C, it maintained a low resistivity of about 2.8 μΩ cm, demonstrating extremely high stabilities against silicide formation.
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This project was supported by the National Science Foundation of China (Grant Nos. 51271045 and 11174044).
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Li, X.N., Zhao, L.R., Li, Z. et al. Barrierless Cu-Ni-Nb thin films on silicon with high thermal stability and low electrical resistivity. Journal of Materials Research 28, 3367–3373 (2013). https://doi.org/10.1557/jmr.2013.355