PZT Transduction of High-Overtone Contour-Mode Resonators

This paper presents the Butterworth-van Dyke model and quantitative comparison that explore the design space of lead zirconate titanate-only (PZT) and PZT on 3-, 5-, and 10-mu m single-crystal silicon (SCS) high-overtone width-extensional mode (WEM) resonators with identical lateral dimensions for incorporation into radio frequency microelectro-mechanical systems (RF MEMS) filters and oscillators. A novel fabrication technique was developed to fabricate the resonators with and without a silicon carrier layer using the same mask set on the same wafer. The air-bridge metal routings were implemented to carry electrical signals while avoiding large capacitances from the bond-pads. We theoretically derived and experimentally measured the correlation of motional impedance (R(X)), quality factor (Q), and resonance frequency (f) with the resonators' silicon layer thickness (t(Si)) up to frequencies of operation above 1 GHz.