Optimal microwave properties of thin BSTO films for high frequency applications

The influence of deposition parameters on microwave properties of Ba/sub x/Sr/sub 1-x/TiO/sub 3/ (BSTO) films deposited on alumina substrate has been investigated in a wide frequency range (1-30 GHz). The best combination of high tunability (n) and low losses (tan /spl delta/) at room temperature was obtained for the 30% Ba content target. The best BSTO films exhibited n=2.1 and tan /spl delta/=0.016 at 1 GHz and zero bias. This result is among the best reported for sputtered BSTO on alumina substrates.