​Abstract: The article presents a MEMS microbridge integrated with two identical MOSFETs in a current mirror configuration. The input MOSFET, embedded on the substrate, serves as a reference MOSFET, while the output MOSFET is placed at the fixed edge of the microbridge to detect deflection-induced mechanical stress. Due to the piezoresistive effect, applied mass changes the channel mobility of the output MOSFET, resulting in changes in drain current and voltage across its drain terminals. Three microbridge-based sensing configurations are investigated: (a) pMOS channel resistive loaded, (b) nMOS channel resistive loaded and (c) dual channel current mirror integrated microbridge mass sensors. Simulation using COMSOL Multiphysics and TSpice software shows sensitivity of approx. 0.11 μV/μg, 2.33 μV/μg and 12.67 μV/μg for pMOS, nMOS and dual channel sensors, respectively. Fabrication process steps and mask-layout design are also discussed. Overall, this study demonstrates a promising and robust approach for highly sensitive low-mass sensing applications.

Keywords: Microelectromechanical systems, Piezoresistive devices, Current mirror circuit, Sensor systems.

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