Composition, Structure, and Dielectric Characteristics of (Sr0.5Ba0.5)Nb2O6/Pt(111)/Si(001) Films

Resumo

Sr_0.5Ba_0.5Nb₂O₆ (SBN) relaxor ferroelectric films of different thicknesses have been grown on Pt(111)/Si(001) substrates by rf sputtering. We have studied their structure, composition–depth profiles, lattice dynamics, and dielectric properties at temperatures from 25 to 200°C. The results demonstrate that the composition of the films does not vary with depth and corresponds to that of the ceramic target used and that the SBN/Pt interface has a transition layer more than 30 nm in thickness, consisting of a mixture of platinum and SBN. According to X-ray diffraction characterization results, the films are polycrystalline, with a preferential orientation of the SBN [001] axis along the normal to the substrate surface. At a film thickness of 950 nm or above, the SBN films on Pt(111)/Si substrates differ insignificantly in unit-cell parameters, lattice dynamics, and Burns temperature from SBN single crystals. We discuss general relationships of structure formation and characteristics of the films.