Self-Sensing Micro- and Nanocantilevers with Attonewton-Scale Force Resolution

Thin, piezoresistive silicon cantilevers are shown to provide unprecedented sensitivity for force detection in an integrated, self-sensing, readily scalable configuration. The devices realized herein are patterned from single-crystal Si epilayer membranes utilizing bulk micro- and nanomachining processes. We demonstrate an electrically transduced force sensitivity of 235 aN/Hz^(1/2) at room temperature and 17 aN/Hz^(1/2) at 10 K. Enhancement of the p+ piezoresistive gauge factor is observed at cryogenic temperatures. The results are employed to elucidate the ultimate, low-temperature sensitivity attainable from self-sensing nanoelectromechanical systems utilizing displacement transduction based upon semiconducting piezoresistors.