Ultra-thin-film AlN contour-mode resonators for sensing applications

This paper reports on the design and experimental verification of a new class of ultra-thin-film (250 nm) aluminum nitride (AlN) microelectromechanical system (MEMS) contour-mode resonators (CMRs) suitable for the fabrication of ultra sensitive gravimetric sensors. The device thickness was opportunely scaled in order to increase the mass sensitivity, while keeping a constant frequency of operation. In this first demonstration the resonance frequency of the device was set to 178 MHz and a mass sensitivity as high as 38.96 KHz·¿m
²
/fg was attained. This device demonstrates the unique capability of the CMR technology to decouple resonance frequency from mass sensitivity.