Authors: Y.H. Park and K.C. Park
Affilation: University of Colorado at Boulder, United States
Pages: 412 - 415
Keywords: MEMS resonator, Q-factor, energy loss, Multiphysics Simulation
Vibration energy transmission from MEMS resonator through anchor to substrate, viz., anchor loss, is examined by utilizing the coupled substrate-resonator-electrostatic numerical model. The resonator is electrostatically excited beam-type structure anchored at both ends onto multi-layered silicon substrate. Many of fabricated resonators exhibit that the anchor loss is a crucial energy loss path limiting the achievement of high Q-factor as operating frequency increases up to HF to VHF ranges. In this study, for the ultimate goal of design improvement, the anchor loss mechanism is numerically modeled and validated by correlation with experiments of a series of clamped beam resonators whose center frequencies range from 8 MHz to 70 MHz. The modeling procedure is divided into two parts: substrate model via a modified classical wave propagation solution, and a resonating beam modeled with finite element method. Then independent two models are coupled by interface compatibility. The validated simulation for 71.8 MHz resonator indicates that the anchor loss is a frequency dependent mechanism that increase with increasing frequency, and the resulting equivalent damping coefficient due to anchor loss is 0.15 % whereas the material damping is only 0.006 %.