VHF monolithically integrated CMOS-MEMS longitudinal bulk acoustic resonator

Presented is a fully integrated solution on CMOS technology for achieving a longitudinal bulk acoustic wave microelectromechanical resonator. The capacitive polysilicon module present in the AMS 0.35 m commercial CMOS technology is used to implement a longitudinal bar with a gap of 40 nm using the interpoly oxide as spacer. Measurements, in air, show a resonance frequency of 258 MHz.