seminar - Advances of MEMS Resonators - 12/3 11-12, Allen 101, Li-Wen Hung, EECS, UC Berkeley

Friday, December 3, 2010
Allen 101
11:00 – 12:00

Advances of MEMS Resonators
Li-Wen Hung, EECS, UC Berkeley

Abstract
MEMS resonators are a possible single-chip solution for frequency
control in miniaturized transceivers. In particular, narrow-band filters
capable of removing the entire out-of-channel interferences relax the
dynamic range and power requirements for the subsequent circuits.

However, so far no MEMS resonator has achieved simultaneously high-Q and
low-impedance, as required by narrow-band filters. Specifically,
capacitive resonators show high Q but high impedance; piezoelectric
resonators attain low impedance but insufficient Q.

This talk will focus on the theory and demonstration of two new
techniques for either reducing the impedance or enhancing the Q of MEMS
resonators:
(1) Silicide-induced gaps, as the single known method for releasing
microstructures without any etching or bonding, form sub-50nm
transduction gaps via only seconds of annealing, compared to hours of
etching limited by mass transportation rate.
(2) Capacitive-piezo resonators post the highest Q ever measured for
sputtered AlN resonators by eliminating electrode losses and, for the
first time, confirm AlN as a high-Q material.
The talk will conclude with future research trends and new applications
enabled by advances of MEMS resonators.

Biography
Li-Wen Hung received her B.S. degree from National Taiwan University,
Taipei, and M.S. degree from University of Michigan, Ann Arbor, both in
Electrical Engineering. She will shortly receive Ph.D. from UC Berkeley.
Her current research interests include micromechanical resonators and
circuits. From 2007 to 2010, she has proposed and demonstrated four new
methods for enhancing resonator performance and has received several
awards, including four Best Paper/Poster Awards from Industry Advisor
Board (IAB) of Berkeley Sensor and Actuator Center (BSAC). Her
innovative work on silicide-induced gaps won the Gold Prize of the
international TSMC Outstanding Student Research Award in 2010. She has
three patents pending.