FBAR Gas Sensors

Small-sized, high-sensitivity, and low-cost sensors are required for gas-sensing applications because of their critical role in environmental monitoring, clinic diagnosis, process control, and anti-terrorism. Given the rapid developments in micro-fabrication and microelectromechanical system (MEMS) technologies, film bulk acoustic resonator (FBAR) gas sensors have received increased research attention because of their improved working frequency and reliability. This chapter discusses the state-of-the-art and recent developments in FBAR gas sensors. The sensing mechanism and limitations of these sensors are summarized. Recent progress in the development of four major aspects of FBAR gas sensors, namely, FBAR gas sensors using different sensing materials, FBAR gas sensors used in electronic noses, system integration of FBAR gas sensors, and FBAR gas sensors used as micro-GC detectors, is reviewed. The potential future of FBAR sensors used in flexible electronics is also discussed.