Pb_(0.3)Sr_(0.7)TiO_(3) thin films for high-frequency phase shifter applications

摘要

Pb_(0.3)Sr_(0.7)TiO_(3) (PST30) thin films were synthesized on platinized silicon (Pt/Si) and lanthanum aluminate (LAO) substrates using chemical solution deposition technique. The films on LAO substrate were highly (100) oriented, whereas the films on Pt/Si substrate were polycrystalline. The low dielectric loss in the PST30/LAO films makes them attractive for fabricating tunable dielectric devices. An eight-element coupled microstrip phase shifter was fabricated on PST30/LAO film and tested in the frequency range ～15-17 GHz. The maximum figure of merit (K=phase shift per dB loss) of ～56°/dB was obtained for PST30 film, which was better than commonly observed value in pure barium strontium titanate films. This makes PST30 a potential candidate material for further investigations for microwave applications.