The solidly mounted resonator (SMR) is composed of a piezoelectric thin film sandwiched between two electrodes and a Bragg reflector that comprises alternating high and low acoustic impedance with a thickness of a quarter wavelength. In this study, the combination Mo/SiO2 is chosen as high/low acoustic impedance materials to form a Bragg reflector; aluminum nitride (AlN) is utilized as the piezoelectric layer. The purpose of this study is to investigate the resonance characteristics of solidly mounted resonators with various pairs of reflecting layers. The experimental results yield an electromechanical coupling of 1.926% and quality factor (Q) of 254 with three pairs of Mo/SiO2 layers. The figure of merit (FOM), which is defined as the product of electromechanical coupling and quality factor, has a maximum of 489 with three pairs of Mo/SiO2 layers.
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