Triple coupled cantilever systems for mass detection and localization

Cantilever sensors have been the subject of a growing attention in the last decades and their use as mass detectors has been proved with attogram sensitivity. Systems of cantilevers on the other hand are still in a preliminary stage and only few devices have been discussed so far. In this paper we propose an original geometry consisting of three mechanically coupled identical cantilevers. We use finite element analysis to investigate the coupling effect on the performance of the system, in particular its mass response. We have fabricated prototypical micron-sized devices, showing that the mass sensitivity of a three coupled cantilever system is comparable to that of a single resonator. We demonstrate that systems of coupled cantilevers offer several advantages over single cantilevers, including less stringent vacuum requirements for operation, mass localization, insensitivity to surface stress and to distributed a-specific adsorption.