Influence of piezoelectric film and electrode materials on film bulk acoustic-wave resonator characteristics

This study adopts the one-dimensional Mason model and basic transmission line theory to investigate the influence of different piezoelectric films and electrode materials on the characteristics of a thin film bulk acoustic-wave resonator (FBAR). The influences of different electrodes, piezoelectric films, and supporting membrane thicknesses are also explored. The results confirm that the material properties and thickness of the piezoelectric film play a significant role in determining the performance of the FBAR, and influence such characteristics as the resonant frequency, the bandwidth, and the insertion loss. Therefore, the choice of piezoelectric material has a pronounced influence upon the subsequent design of the FBAR filter. Since the results also demonstrate that the resonant frequency of the FBAR is influenced by the thickness of each of the layers within the acoustic wave path, and by the resonance area, the potential exists to tune the characteristics of the FBAR by specifying appropriate geometric parameters during the FBAR design stage.