We report on the electrochemical process and nucleation mechanism of the “direct-on-barrier” electroplating of copper on ultrathin cobalt adhesion layer from an alkaline CuSO4 and ethylenediamine (En) bath without additives. Results show that the corrosion current density was much lower in the alkaline bath than that in the commercial acidic bath due to formation of the CuEn22+ species in the aqueous CuSO4-En solution. The CuEn22+ species can well stop the reaction between the copper ions and Co by reducing the potential of copper ions. The current-time transients were not typical of a diffusion-limited nucleation and growth. Pure instantaneous or progressive nucleation of copper on Co layer was not observed. The impact of current density on the orientation, resistance and morphology was studied. Copper film in 250 nm thick was successfully deposited on the 10 nm Co film in the patterned wafers. And Cu was electroplated onto ultrathin Co layer with ∼5 nm thickness and TEM result shows that there is no obvious Co thickness loss.

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The recently synthesized novel figure-of-eight nanohoop with two strained oligoparaphenylene (OPP) was theoretically designed to collect and stabilize new allotropic carbon cyclo[18]carbon (C18) through molecular assembly. The size adaptability and...

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Over the past years, hard wear resistant TiN coatings deposited by magnetron sputtering have gained increasing importance in the field of decorative and cutting tool coatings. With the ongoing trend to multifunctional operating cutting tools, new solutions in the design of tools are demanded. The alloying of TiN coatings with additional elements, for instance, can effectively enhance hardness, wear resistance and so on. Both TiAlN and TiSiN coatings, well-studied nitride systems, yield superior oxidation resistance, and extend the life of cutting tools by significant margins in comparison with TiN coatings. Numerous research activities focus on TiAlN, TiSiN systems, whereas limited efforts have been made to characterize TiMoN coatings. Low coefficient of friction is a common property in various Mo-containing coatings that can react with oxygen in the air into Magnéli phase (MoO 3 ). The effects of Mo alloying on mechanical properties and wear resistance of TiN-based coatings remain to be investigated. TiMoN composite films with various Mo concentrations were deposited using RF reactive magnetron sputtering and characterized by SEM, EDS, XRD, nano-indentation and wearing tester. The results show that TiMoN coatings have fcc structure. When atomic fraction of Mo in total metallic elements (X) is less than 68.37%, a TiMoN solid solution was formed by dissolution of Mo into the TiN lattice; when X is more than 68.37%, a TiMoN solid