Preparation and properties of Ru and RuO2 thin film electrodes for ferroelectric thin films

Ru and RuO2 thin films were prepared by RF magnetron sputtering. The crystalline structure and electrical properties of these films were investigated. Reactive sputtering of a ruthenium metal target was carried out in a mixed gas of argon and oxygen at 580 °C. Total pressure (PO(2)+PAr) was controlled to maintain a constant pressure of 1 Pa. The RuO2 single phase could be obtained when PO(2) was 0.5 Pa and the deposition rate was about 30 nm/min. The resistivity of the 290 nm-thick RuO2 thin films deposited on SiO2(1000 nm)/Si was 54.9 μΩ&middotcm. However, the resistivity increased with decreasing film thickness. Fatigue resistance of (Pb, La)TiO3 thin films with RuO2 as top and bottom electrodes was improved compared to the films on Pt electrodes.