Epitaxial growth of low-resistivity RuO 2 films on [formula omitted]-oriented Al 2O 3 substrate

Abstract

Highly conducting epitaxial RuO 2 films with a thickness of 0.5 μm were grown by metal-organic chemical vapour deposition on (1 0 0) Si and (1 1 ̄ 0 2) -oriented Al 2O 3 single crystal substrates. Different structure was observed for the RuO 2 films on these substrates; the films on Si substrate were polycrystalline, while X-ray diffraction analysis revealed epitaxial growth of RuO 2 on the Al 2O 3 substrates. Electrical properties (room-temperature resistivity and residual resistivity ratio) of the RuO 2 films were studied in connection with their preparation conditions, structure and morphology. Epitaxial RuO 2 films on (1 1 ̄ 0 2) -oriented Al 2O 3 single crystal substrates exhibit low resistivity at room temperature ρ 300≅30 μΩ cm and residual resistivity ratio up to 30. Moreover, the residual resistivity ratio of the RuO 2 films on the Al 2O 3 substrate can be increased by additional annealing in oxygen atmosphere to the value as high as 60.