Mems device and fabrication method thereof

Abstract

A microelectromechanical systems (MEMS) device includes: a surface acoustic wave (SAW) filter including an interdigital transducer; a first structural layer disposed over the SAW filter; and a bulk acoustic wave (BAW) filter disposed over the first structural layer. The BAW filter includes a supporting substrate, an acoustic reflective structure disposed over the supporting substrate, and a piezoelectric stack structure disposed over the acoustic reflective structure. The piezoelectric stack structure includes a first electrode, a piezoelectric layer, and a second electrode. The first structural layer includes a first cavity covered by an effective resonance region of the piezoelectric stack structure and the interdigital transducer of the SAW filter.

Dependencies are inferred from the claim text.