Significant resonance characteristic improvements by combined use of thermal annealing and Co electrode in ZnO-based FBARs

Abstract

Resonance characteristics improvements by the combined use of thermal annealing of the W/SiO2 Bragg reflectors and Co electrodes in ZnO-based film bulk acoustic resonator (FBAR) devices are presented. Their resonance characteristics could be significantly improved by the thermal annealing particularly at 400degreesC/30 min. In addition, the use of Co electrodes has resulted in further improvement of the resonance characteristics, compared to the use of Al electrodes.