Analysis of resonance characteristics of Bragg reflector type film bulk acoustic resonator

The film bulk acoustic resonator (FBAR) is one of filter devices for information and communication and is expected to apply to biosensor because of its excellent resonance characteristics. This study was conducted to analyze the factors affecting the resonance characteristics of FBAR by modeling and simulation. The acoustic Bragg reflector type FBAR (ABR-FBAR) consisting of piezoelectric thin film such as ZnO, top and bottom electrodes, acoustic reflector and substrate was assumed. The mathematical model describing the input impedance of ABR-FBAR was derived and verified by PZT element with ABR structures. The design parameters for ABR-FBAR factors such as thickness of electrode, and number, order and thickness of ABRs were analyzed by simulation of the derived model.