Dielectric properties of epitaxial Ba0.5Sr0.5TiO3 films on amorphous SiO2 on sapphire -: art. no. 072905

The strain-relieved crystalline Ba0.5Sr0.5TiO3 (BST) film on SiO2/Al2O3 was achieved by combining a molecular-beam epitaxy of BST on Si/Al2O3 and a post-growth anneal in oxygen at elevated temperatures. The oxidation anneal not only converted the thin Si interlayer into amorphous SiO2 and eliminated the dielectric loss from the Si, but also relieved local strain in the film. The resulting BST film showed promising dielectric properties with 66% tunability and 0.016 dielectric loss, respectively. Additionally, temperature-dependent permittivity of the BST film resembled that of the bulk BST ceramics. (C) 2005 American Institute of Physics.