Spurious free and temperature stable Giga-hertz acoustic wave resonators with enhanced quality factor

With the electromagnetic spectrum becoming significantly crowded, it is highly challenging to satisfy the tightening wireless specifications with the increasingly shrinking RF components in mobile equipment. High performance and miniature acoustic resonator is crucial to build the critically important RF components such as RF filters, RF duplexers and RF oscillators. This paper presents a high Q, spurious free and temperature stable bulk acoustic wave resonator. A novel approach is proposed to tune the resonator´s acoustic dispersion behavior to suppress spurious resonances and acquire a clean electrical frequency response. A SiO₂ temperature compensation layer is introduced into the resonator structure to achieve nearly zero TCF performance. The Q of the resonator is greatly enhanced by a raised frame structure applied at the periphery of the resonator.