INFLUENCE OF SILICON ON QUALITY FACTOR, MOTIONAL IMPEDANCE AND TUNING RANGE OF PZT-TRANSDUCED RESONATORS

Abstract

This paper provides a quantitative comparison and explores the design space of PZT-only (Lead Zirconium Titanate) and PZT-on-Silicon length-extensional mode resonators for incorporation into RF MEMS filters and oscillators. We experimentally measured the correlation of motional impedance (R X ) and quality factor (Q) with the resonators' silicon layer thickness (t Si ). For identical lateral dimensions and PZT-layer thickness (t PZT ), the PZT-on-Silicon resonator has higher resonant frequency (dominated by silicon), higher Q (5,100 vs. 140) and lower motional impedance (51 vs. 205 ). However, PZT-only resonator demonstrated much wider frequency tuning range (5.1% vs. 0.2%).