(Invited) Cantilever-Based Resonant Chemical Microsensors

Abstract

This paper reviews cantilever-based resonant chemical microsensors, which detect an analyte of interest via a change of the resonance frequency of a characteristic vibration mode, caused by the added mass upon sorption of the analyte into a sensing film deposited on the cantilever surface. While the focus of the paper is on silicon-based, hammer-like resonant sensors that comprise a head region suspended by a cantilever support structure, the results can be applied to other material systems and resonator geometries as well. The cantilever vibrations are excited electrothermally and sensed using four piezoresistors arranged in a Wheatstone bridge. Approaches to address the three ‘S’ metrics of chemical sensors, i.e., sensitivity, selectivity, and stability are highlighted. In particular, the benefits of localized deposition of the sensing film and the analysis of signal transients are explored.