Structural and electrical properties of ternary Ru–AlN thin films prepared by plasma-enhanced atomic layer deposition

Ruthenium–aluminum-nitride (Ru–AlN) thin films were grown by plasma-enhanced atomic layer deposition (PEALD) at 300 °C. The Ru intermixing ratio of Ru–AlN thin films was controlled by the number of Ru unit cycles, while the number of AlN unit cycles was fixed to one cycle. The electrical resistivity of Ru–AlN thin film decreased with increasing the Ru intermixing ratio, but a drastic decrease in electrical resistivity was observed when the Ru intermixing ratio was around 0.58–0.78. Bright-field scanning transmission electron microscope (BF-STEM) and energy-dispersive X-ray spectroscopy (EDX) element mapping analysis revealed that the electrical resistivity of Ru–AlN thin film was strongly dependent on the microstructures as well as on the Ru intermixing ratio. Although the electrical resistivity of Ru–AlN thin films decreased with increasing the Ru intermixing ratio, a drastic decrease in electrical resistivity occurred where the electrical paths formed as a result of the coalescence of Ru nanocrystals.

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► Ru–AlN thin films were grown by plasma-enhanced atomic layer deposition (PEALD).
► Structural properties were systematically investigated by XRD, BF-STEM and EDX.
► A drastic decrease in resistivity was due to the microstructural change of the films.