Tunable BaxSr1−xTiO3 FBARs based on SiO2/W Bragg reflectors

Experimental performance of tunable Film Bulk Acoustic Wave Resonators (FBAR) using paraelectric phase Ba
_x
Sr
_1-x
TiO
₃
(BSTO) thin films is reported. It is shown that the SiO
₂
/W based Bragg reflectors deposited on high resistivity substrates withstand relatively high deposition temperatures (<; 600C) of the ferroelectric films without defects and delamination. Tunable FBARs with Qf products more than 1000 are demonstrated experimentally. Potentials of increasing the Q-factor and tunability are considered.