Fall 2012 IAB & Research Review
September 19 to 21
Advances in Piezoelectric RF MEMS Lamb Wave Resonators
MEMS resonators offer new prospects for a variety of important applications including mass sensing, biosensing, digital logic circuits, and signal processing. In general, high quality factors, excellent thermal stability, and high resonance frequencies are the required features. Recently, micromachined Lamb wave resonators have attracted great attention since it combines the advantages of BAW and SAW: ultra-high phase velocities and multiple frequencies excitation by interdigital transducers (IDT).
This talk will cover the recent progress in aluminum nitride (AlN) Lamb wave resonators utilizing the lowest-order symmetric (S0) mode. More specifically, we will present how to improve the temperature-frequency stability of the AlN Lamb wave resonators by adding a layer of silicon dioxide. The Q’s of Lamb wave resonators can be significantly enhanced using biconvex edges. Moreover, we will report the most recent results on the AlN/SiC Lamb wave resonator utilizing the third-order symmetric (QS3) mode which exhibits a low motional impedance of 91 ohms and a high Q of 5510 at a resonance frequency of 2.92 GHz, resulting in the highest product of 1.61×10^13 Hz among the suspended piezoelectric thin film resonators reported to date.