Movable Gate MOSFETs as Readout Devices for Cantilever-Based Nano-Electromechanical Sensors

Abstract

This work proposes a novel readout mechanism for highly sensitive cantilever-based mass sensors using movable-gate (MG) MOSFETs. Traditional dynamic-mode cantilever sensors measure mass through shifts in resonance frequency, which offer high precision but require complex analog circuitry and large device areas, limiting integration and miniaturization. In contrast, the proposed approach exploits strong short-channel effects in MG MOSFETs, where the drain current depends exponentially on cantilever position, allowing for orders-of-magnitude changes without analog-to-digital conversion. Numerical simulations and initial experiments demonstrate the feasibility of this approach, which also avoids pull-in instability by using the electrostatic behavior of the gate-channel system to stabilize and even excite oscillations. The concept paves the way for scalable, low-complexity, high-resolution mass sensing with full circuit integration potential.