Epitaxial growth of high-κ TiO2 rutile films on RuO2 electrodes

Polycrystalline and epitaxial RuO2∕TiO2∕RuO2 structures were prepared by a combination of metal organic chemical vapor deposition and atomic layer deposition techniques. TiO2 layer grew in a rutile structure due to epitaxial growth on the RuO2 seed layer and exhibited high dielectric constant of 120. Equivalent oxide thickness as low as 0.5nm with a leakage current density of 6×10−6A∕cm2 at 0.8V bias voltage was obtained for the RuO2∕TiO2∕RuO2 capacitor structure epitaxially grown on (11¯02) sapphire substrate. Analysis of leakage currents revealed uneven distribution of defects in the TiO2 dielectric layer.