RUO2 THIN-FILMS AS BOTTOM ELECTRODES FOR HIGH DIELECTRIC-CONSTANT MATERIALS

Ruthenium dioxide (RuO2) thin films are evaluated as a bottom electrode for SrTiO3. It was found that a thin RuO2(50 nm)/Ru(20 nm) layer on Si is quite effective as a barrier layer for both orygen atoms and metals when depositing SrTiO3 ata relatively low temperature of 450-degrees-C. To test its suitability for high-temperature processes such as CVD of SrTiO3, the RuO2/Ru electrode on Si was annealed in air at 600-degrees-C for 1 hour. Even under this severe condition, the electrode using 100-nm-thick RuO2 was sufficient for preventing oxygen diffusion into Si.