Deposition and characterization of crystalline conductive RuO₂ thin films

Highly conductive metal-oxide RuO₂ thin films have been successfully grown on yttria-stabilized zirconia (YSZ) substrates by pulsed laser deposition. Epitaxial growth of RuO₂ thin films on YSZ and the atomically sharp interface between the RuO₂ and the YSZ substrate are clearly evident from cross-sectional transmission electron microscopy. A diagonal-type epitaxy of RuO₂ on YSZ is confirmed from x-ray diffraction measurements. The crystalline RuO₂ thin films, deposited at temperatures in the range of 500 °C to 700 °C, have a room-temperature resistivity of 35 ± 2 μΩ-cm, and the residual resistance ratio (R₃₀₀k/R_{4.2 k}) is around 5 for the crystalline RuO₂ thin films.