Title :
A High-Quality-Factor Film Bulk Acoustic Resonator in Liquid for Biosensing Applications
Author :
Xu, Wencheng ; Zhang, Xu ; Choi, Seokheun ; Chae, Junseok
Author_Institution :
Sch. of Electr., Comput. & Energy Eng., Arizona State Univ., Tempe, AZ, USA
Abstract :
We report a high-quality-factor (Q) film bulk acoustic resonator (FBAR) operating in liquid environments. By integrating a microfluidic channel to a longitudinal-mode FBAR, a Q of up to 150 is achieved with direct liquid contacting. A transmission line model is used to theoretically predict the Q behavior of the FBAR. The model suggests an oscillatory pattern of Q as a function of the channel thickness and the acoustic wavelength in the liquid, which is experimentally verified by precisely controlling the channel thickness. This FBAR biosensor is characterized in liquids for the real-time in situ monitoring of the competitive adsorption/exchange of proteins, the Vroman effect. The FBAR offers a minimum detectable mass of 1.35 ng/cm2 and is successfully implemented in a Pierce oscillator as a portable sensing module.
Keywords :
Q-factor; acoustic resonators; adsorption; biochemistry; biosensors; bulk acoustic wave devices; crystal resonators; fluid oscillations; microchannel flow; molecular biophysics; piezoelectric materials; piezoelectric semiconductors; portable instruments; proteins; semiconductor device models; semiconductor thin films; transmission line theory; zinc compounds; FBAR biosensor; Pierce oscillator; Vroman effect; ZnO; biosensing applications; channel thickness; direct liquid contacting; high-quality-factor film bulk acoustic resonator; longitudinal-mode FBAR; microfluidic channel; oscillatory pattern; portable sensing module; protein adsorption; protein exchange; real-time in situ monitoring; transmission line model; $Q$ factor; Acoustic resonators; biomedical transducers; piezoelectric resonators;
Journal_Title :
Microelectromechanical Systems, Journal of
DOI :
10.1109/JMEMS.2010.2093568
