Research and Design of High Sensitivity FBAR Micro-mass Sensors

Abstract

Micro-mass sensors have important application in chemical and biological sensing. Based on the theory of thin film bulk acoustic resonator (FBAR), this paper represents four designs of different micro-mass sensor models. COMSOL Multiphysics™ software is used to simulate the FBAR sensor sensitivity, which with low-impedance acoustic layer and additional electrode frame. In the finate element simulation models, five different values of mass-loading were applied. From the experimental results, the characteristic parameters and the sensitivity of the FBAR sensors were obtained. It is known to us that the FBAR sensor’s frequency quality factor can be improved by using the electrode frame, and its sensitivity can be enhanced by using the low-impedance acoustic layer. To sum up, the above analysis shown that the best sensitivity is 1.351 × 10-12ng/μm2/Hz and the frequency quality factor is 1415, which is the FBAR sensor with a single-step electrode frame and a low-impedance acoustic layer.

A review of piezoelectric MEMS sensors and actuators for gas detection application

“…Furthermore, FBAR possesses more favored piezoelectric properties including high acoustic velocity [258], high electromechanical coupling coefficient ( k 2 ) [259], and low acoustic loss [260]. It has been proven that bringing all these unique properties besides the ultra-thin piezoelectric films such as AIN which is in the thickness of a nanometer, all of these properties can help to produce unique FBAR devices which possess very high resonant frequencies usually from sub-GHz to 10 GHz and high-quality factor [261].…”

Design of low phase noise FBAR oscillator based on Pierce structure

“…FBAR and saw are widely used in RF applications. Because FBAR has the advantages of small size, low insertion loss, low power consumption and high frequency, it is more suitable for UHF applications than surface acoustic wave(SAW) [4] . FBAR shows great potential in miniaturization and integration of micro electro mechanical system (MEMS) oscillators [5] .…”