Growth of high-dielectric-constant TiO2 films in capacitors with RuO2 electrodes

摘要

Titanium dioxide thin films were grown on RuO2 layers by atomic layer deposition. The stabilizing effect of the bottom rutile-type RuO2 layer resulted in growth of the TiO2 rutile films at temperatures above 275 degrees C. Stabilization of the TiO2 rutile phase occurred due to local epitaxial growth of the polycrystalline RuO2/TiO2/RuO2 structure, as revealed by transmission electron microscopy. A dielectric constant as high as 155 and equivalent oxide thickness (EOT) as low as 0.5 nm were determined from the capacitance-voltage measurements for the TiO2 films grown above 275 degrees C. A leakage current density of 10(-3) A/cm(2) at 1 V bias voltage was obtained for the films with EOT equal to 0.5 nm.