Multi-band RF filter integrating different modes of AlN resonator by CMOS-compatible process

A compact multi-band RF front-end architecture is strongly required and a multi-band RF filter bank is a key component for future mobile phones based on cognitive wireless technology. We have developed a novel CMOS-compatible process for the integration of a multi-band filter with LSI. Different modes of AlN/Si composite piezoelectric MEMS resonators, i.e. film bulk acoustic resonators (FBARs) and disk-type resonators, were co-fabricated on a dummy Si wafer. A ladder-type FBAR filter with a center frequency of 7.71 GHz and a mechanically-coupled disk-array filter with a center frequency of 292.8 MHz were also prototyped and characterized.