Theoretical analysis of bulk acoustic wave resonators with emerging -Ga₂O₃ piezoelectric film

In this paper, the theoretical analysis of 2.3 GHz bulk acoustic wave (BAW) resonators with emerging epsilon-Ga2O3 piezoelectric films was investigated. By using the finite element method to calculate the dispersion curve of the BAW resonator based on epsilon-Ga2O3, we designed and optimized the Bragg reflector structure as well as the metal frame to suppress transverse energy leakage. When the width of the raised metal frame is an odd multiple of the quarter wavelength of the S-1 Lamb mode, the vibration displacement at the boundary of the resonators is significantly suppressed, and the acoustic energy is concentrated as much as possible in the effective area of the resonators, resulting in improvement of the Q(p) and Q(max). Therefore, the epsilon-Ga2O3 based BAW resonators with Bode Q(max) (similar to 1488), electromechanical coupling coefficient k(eff)(2) (similar to 15%), and the figure of merit (FoM) coefficient (similar to 223) are simulated and designed. Detailed theoretical analysis provides the key theoretical guidance and design scheme for the realization of epsilon-Ga2O3 BAW filters. The above-mentioned results imply that the emerging epsilon-Ga2O3 piezoelectric semiconductors have application prospects in BAW resonators and radio frequency front-end fields.