Pt/RuO2 Hybrid Bottom Electrodes and Their Effects on the Electrical Properties of (Ba, Sr)TiO3 Thin Films

Thin platinum layer of 100 Å thickness was used for the modification of the interface state between (Ba, Sr)TiO3 (BST) thin films and RuO2 bottom electrodes. Pt/RuO2 hybrid bottom electrodes were fabricated with various platinum deposition temperatures by a conventional dc magnetron sputtering method. Although the surface morphology and X-ray diffraction (XRD) patterns of BST thin films were not changed, the electrical properties of BST films deposited on Pt/RuO2 hybrid electrodes were improved compared to the films on RuO2 electrodes. Dielectric constant (ε r) and leakage current density of the 1000 Å thick BST thin films on Pt/RuO2 hybrid electrodes prepared at the platinum deposition temperature of 400°C were 498 and 8.6×10-8 A/cm2 at 1.5 V, respectively.