Self-oscillation conditions of a resonant-nano-electromechanical mass sensor

TL;DR

This paper analyzes the design and performance of co-integrated oscillators for nano-electromechanical mass sensors, comparing capacitive and piezoresistive transduction schemes and their sensitivity.

Contribution

It provides a comprehensive model and design methodology for NEMS-based mass sensors, highlighting the superior sensitivity of piezoresistive transduction at high frequencies.

Findings

Piezoresistive sensors are more sensitive than capacitive ones.

High doped silicon piezoresistive gauges offer similar resolution to metallic gauges.

The developed model aligns well with experimental observations.

Abstract

This article presents a comprehensive study and design methodology of co-integrated oscillators for nano mass sensing application based on resonant Nano-Electro-Mechanical-System (NEMS). In particular, it reports the capacitive with the piezoresistive transduction schemes in terms of the 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 much 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 a great interest for very large scale integration displays similar theoretical resolution than the metallic gauge already used experimentally.