SOL-GEL DERIVED TEXTURED BARIUM STRONTIUM TITANATE THIN FILMS FOR MICROWAVE DIELECTRIC APPLICATIONS

摘要

Highly (100) oriented Ba_(0.5)Sr_(0.5)TiO_3 {BST50} and Ba_(0.6)Sr_(0.4)TiO_3 {BST60} thin films were successfully grown on LaAlO_3 (LAO) (100) substrates by sol-gel technique. The in-plane epitaxial nature of these films was confirmed by X-ray pole figure analysis and Rutherford backscattering (RBS) channeling measurements. The effect of manganese (Mn) doping and BST:MgO heterostructure on the nature of epitaxial growth and electrical behavior of (100) oriented (BST50) thin films were studied. These films exhibited excellent phase shift and insertion loss characteristics at microwave frequencies. The BST50 film with 3 at% Mn doping showed improvement in the phase shift (337° at 339 V and at ～14 GHz) and BST:MgO film showed the considerable reduction in the insertion losses (～3.4 dB at 400 V and at 16.25 GHz) for the phase shifters measured in the high frequency region.