PREPARATION AND CHARACTERIZATION OF IRIDIUM OXIDE THIN-FILMS GROWN BYDC REACTIVE SPUTTERING

Iridium oxide (IrO2) thin films were successfully grown by a DC magnet ron reactive sputtering method. It was found that the crystalline natu re and morphology of IrO2 films were strongly dependent on the oxygen partial pressure, total pressure and growth temperature. The growth of IrO2 is well explained by the generic curve for the total pressure as a function of Oz content. The films showed good barrier performance b etween Pt and poly-Si up to 750 degrees C. A 40-nm-thick Ba0.5Sr0.5TiO 3 film was grown by RF magnetron sputtering on the Pt/IrO2/poly-Si ele ctrode. The leakage current density and dielectric constant of a Pt/Ba 0.5Sr0.5TiO3/Pt capacitor on the IrO2/poly-Si electrode were comparabl e to those of the capacitor on a SiO2/Si substrate. However, an additi onal ohmic layer was required to prevent the formation of a SiO2 layer between the IrO2 and poly-Si.