Effects of Bragg reflector annealing on performance factors of FBAR-based ultramass-sensitive sensors

We present the film bulk acoustic wave resonator-based ultramass-sensitive (FBAR-UMS) sensors in which their resonance characteristic improvements, mainly due to Bragg reflector (BR) annealing, favorably influence their performance factors. We fabricated two kinds of FBAR-UMS sensors, respectively, with nonannealed and annealed BRs (namely, nonannealed and annealed sensors) and investigated the effects of BR annealing on their performance factors by comparing their resonance frequency shift (−Δfr), measured before and after each mass loading (Δm). As a result, the annealed sensors showed much larger mass-loading effect and detectable mass range than the nonannealed ones. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2134–2137, 2015