Characterization and simulation of the first extensional mode of rectangular micro-plates in liquid media

This Letter reports on the characterization of the first extensional mode of AlN-actuated mid-point supported resonant microplates in liquid media. Devices of different dimensions were fabricated and both optical and electrical measurements were performed in order to identify the modal shape under study and determine its quality factor. The dependence of the quality factor on the plate dimensions is discussed based on analytical and finite element simulation results. A quality factor of 100 was achieved in water at 3.8 MHz, and the suitability of this kind of device to work under high viscous condition (up to 51 cP) was demonstrated.