Technical Papers and Presentations

The shear mode of film bulk acoustic resonators (FBARs) is preferred to the longitudinal mode owing to its lower acoustic losses in a liquid. However in addition to mass loading, the resonance is also affected by temperature and liquid viscosity. These two parameters can either be sensed or compensated using a layer of silicon dioxide, which has a unique temperature coefficient of elasticity. In this work, we aim to characterise the effect of temperature and viscosity on all the individual resonances in a four-resonance-mode zinc oxide FBARs for biosensors. We determine that the shear mode is less sensitive to temperature than the longitudinal mode. Our future work will focus on characterising the viscosity effect on each mode.