Mass Sensitivity of Thin Film Resonator Devices

A systematic study of the influence of the materials´ properties and thickness in composite thin film bulk acoustic resonators (FBAR) on the mass sensitivity is presented. Calculations based on the Mason transmission line model are presented along with some preliminary experimental results. We present and investigate the concept of sensitivity amplification in the mass sensitive regime and show how this amplification correlates with wave reflection and interference within the composite structure. Asymmetrical resonators where the sensitivity differs between the two different surfaces are also presented.