High Performance Coupled BAW/SAW Resonator Using ScAlN/AlN Thin Film Hetero Acoustic Layered (HAL) Structure

This paper presents a high-performance coupled BAW/SAW resonator based on ScAlN/Aln thin film hetero acoustic layered (HAL) structure. The influences of the SAW propagation characteristics for different geometrical parameters and configurations are investigated. The SAWs excited in the proposed HAL structure exhibits excellent performance due to the combined advantages of the coupling of BAW and SAW and its energy confinement effect. The optimized Mo/ScAlN/AlN/Mo/SiO2/Si structure exhibits a strong piezoelectric coupling (K-2) of 21% and a high phase velocity (V) of 5100m/s. And, a Q(r) is 3548 and Q(ar) is 1348 around the resonance frequency of 4.83GHz and the anti-resonance frequency of 5.32GHz respectively. The coupled BAW/SAW resonator with large K-2, high V and high Q provides promising prospects for development of high frequency, broadband and low-loss filters for 5G application.