Finite element simulation of SMFBAR based sensor

In this work, a three dimensional finite element model for solidly mounted film bulk acoustic resonator (SMFBAR) devices is developed and simulated. The simulation is performed using the CoventorWareTM platform to analyze the performance of the device. The influence of the shape of the top electrode and its thickness on the sensitivity SMFBAR based sensors was investigated. Two different electrode shapes (square and circle) with surface areas of 0.04 mm2 and 0.09 mm2 and different thicknesses varying from 50 nm to 350 nm with increments of 100 nm were investigated. The devices that were studied were ZnO based SMFBAR structures. The analysis revealed that both configurations have mass sensitivities with three orders of magnitude higher than that of quartz crystal microbalance sensing systems. These devices also exhibit high performance with maximum quality factor of 418 and effective electromechanical coupling coefficient of around 12.2%. Also, it was found out that the circular shaped top electrodes performance were slightly higher than that of square shaped one with respect to sensitivity, quality factor and effective electromechanical coupling.