Design and Simulation of a Closed Loop Controlled Linear Displacement MEMS Micromotor, Based on a Floating Gate Transistor

This work consists of a proposal of a micromotor with a linearly displaced shaft, driven by electrostatic forces designed for CMOS-MEMS technology. Four springs and a set of mobile electrodes make up the body of the micromotor; in turn, a plate whose function is to sense the position is attached to the main body, making the system a closed loop instance. A floating gate MOS transistor (FGMOS) is connected to the sensor plate of the micromotor’s body to form the sensing system. The main body is made of a structural layer of aluminum, while a layer of polysilicon is used for the floating gate of the transistor which can operate as the shaft’s position sensor. The proposed electronics and microsystem are monolithic, and the substrate is a single silicon wafer. Multiphysics simulations of the micromotor were performed considering a quasi-static case, since it is the one that best suits the behavior of the proposed micromotor, the results of the simulations show good agreement with the theoretical model.