Influence of Pt, RuO 2 and SrRuO 3 Intermediate Layers on Characteristics of (Sr 0.5Ba 0.5)Nb 2O 6 Thin Films

The influence of Pt, RuO2 and SrRuO3 intermediate layers on the growth of (Sr0.5Ba0.5)Nb2O6 (SBN) thin films and their related electrical properties has been examined. Crystalline SBN films on Pt-coated Si can be obtained at substrate temperatures higher than 720°C (1 mbar), whereas the formation of SBN films on RuO2-coated Si is difficult, due to the instability of the RuO2 layer at high substrate temperatures. On the other hand, SrRuO3 layers deposited at 600°C (0.1 mbar) not only possess good electrical conductivity (ρ s ≈0.5 mΩcm), making them suitable for use as base electrodes, but also have good lattice matching with SBN materials, which markedly enhances the formation of SBN films. However, a special procedure including the deposition of SBN thin films at 600°C (0.1 mbar) to preserve the perovskite phase of the predeposited SrRuO3 layers, followed by postannealing at 750°C (1 atm) to fully crystallize the SBN materials, is required to obtain optimum multilayer films. The remanent polarization thus obtained is around P r=2.8 µC/cm2 and the leakage current density is around J1 =10-7 A/cm2.