Growth characteristics and properties of RuAlO hybrid films fabricated by atomic layer deposition

[Display omitted] •RuAlO hybird films were synthesized by alternating ALD sequences of Al2O3 and Ru.•Nucleation delay was observed when Ru was deposited on Al2O3, not the other way.•With a low Ru cycle ratio, isolated Ru particles are embedded in the Al2O3 matrix.•With a high Ru cycle ratio, Ru nucleus coalesce into a continuous film.•Electrical resistivity of the hybrid film could be adjusted over 10-3 ∼ 1011 Ω·cm. In this work, RuAlO hybridfilmswere synthesized by alternating ALD sequences of Al2O3and Ru for electrical conductivity regulation.O2exposure has significant effectson the nucleation and etching processes of Ru, therefore the O2exposure was first optimized for efficient growth of Ru. A set of RuAlOhybrid films with different Ru subcycle ratioswere fabricated.In-situ quartz crystal microbalance (QCM) measurementrevealed acertain nucleation delaywhenRu was deposited on the surface ofAl2O3, whileno nucleation delay was observed when Al2O3was deposited on Ru. High resolution transmission electron microscopy(HRTEM) characterization confirmed formation ofRu grains embedded in amorphous Al2O3matrix. Elemental mapping results demonstrated that RuandAlelementsareuniformly distributedon the cross section ofthe film.In the grazing incidence angle X-ray diffraction (GIAXRD) patterns ofRuAlOhybrid films,characteristic diffraction peaks of Ru appear with aRusubcycle ratio ≥ 70 %. By properly tuning the Ru to Al2O3ALD subcycle ratio, electrical resistivity of theRuAlOhybrid film could beadjusted over a wide range of 10-3 ∼ 1011Ω·cm.