Effect of design parameters on thin film bulk acoustic resonator performance

摘要

Film bulk acoustic resonators (FBARs) have received considerable attention for micro-electromechanical systems (MEMS) applications such as RF filters, resonators, and recently, bio-sensors. FBARs consisting of a piezoelectric thin film and an acoustic reflector for acoustic isolation from the surrounding medium are advantageous due to the intrinsic high sensitivity to mechanical, chemical, or electrical perturbation and compatibility with standard CMOS processing. In this work, we investigated the resonance characteristics of acoustic Bragg reflector-type FBARs by the model-based parametric analysis. The effect of various thicknesses and materials of electrodes and structural variation of acoustic Bragg reflectors on the key performance characteristics was studied to identify optimal design parameters for high performance FBAR devices. The key performance characteristics of FBARs include impedance characteristics, reflection coefficients, electro-mechanical coupling coefficients, and Q factors. These results not only offer new insights into design guidelines for high performance FBAR devices but also help better understanding of the fundamental physical phenomenon at resonances of the device.