MoS$_{2}$ MEMS-FET Nn Force Sensor With Suspended Body FET and Piezoresistive-Based Hybrid Transduction

Abstract

In this letter, we present a comprehensive study on the design, simulation, and modeling of nano-Newton (nN) force sensor using 2-D molybdnem disulphide (MoS$_{2}$)-based suspended body dual-gate field-effect transistor (2D SB-DG-FET) with integrated piezoresistor. The sensor uses the hybrid transduction scheme involving suspended body (SB) FET and piezoresistive load resistors in common source amplifier (CSA) configuration. The sensor consist of a MoS$_{2}$-based FET integrated on a suspended microelectromechanical systems (MEMS) structure with MoS$_{2}$ piezoresistors acting as a load. The choice of MoS$_{2}$ allows the use of same functional material as both FET channel and piezoresitive load. During force sensing, MEMS structure ensures the constant gate capacitance change leading to an output current change of the SB-DG-FET. Simultaneously the applied force also causes resistance change in the piezoresistors. COMSOL Multiphysics 6.0 and CoventorWare MP 10.3 have been used for the design and simulation of the MEMS structure. The design and simulation of the 2D SB-DG-FET and its application in CSA configuration with piezoresistive load have been carried out in COMSOL using a lookup table. The CSA exhibits the linear response with output sensitivity 1.15 $\upmu \text{V}/\text{nN}$ and maximum detection range upto 2 $\upmu \text{N}$. This letter demonstrates the advantage of this hybrid transduction scheme due to the response of SB-FET and piezoresistor in CSA circuit.