Self-oscillation conditions of a resonant nanoelectromechanical mass sensor

Abstract

This article presents a comprehensive study and design methodology of cointegrated oscillators for nanoscale mass sensing applications based on resonant nanoelectromechanical system (NEMS). In particular, a comparison is provided between the capacitive and the piezoresistive transduction schemes in terms of overall sensor performance. The developed model is clearly in accordance with the general experimental observations obtained for NEMS-based mass detection. The piezoresistive devices are more sensitive (up to 10 zg/√Hz) than capacitive ones (close to 100 zg/√Hz) since they can work at higher frequency. Moreover, the high doped silicon piezoresistive gauge, which is of great interest for very large scale integration, shows similar theoretical resolution to that of the metallic gauge already used experimentally.