A MEMS Capacitive Inertial Sensor with Near Nanoscale Capacitance Plate Spacing

In this paper, a high precision micro inertial sensor with movable lateral electrodes embedded in the two grid vibrators is presented. Through ampere force produced by the electromagnetic driving principle, the initial sensing capacitance spacing of inertial sensor can be reduced theoretically to near nanometer scale. The fringe effect of sensing capacitor with different overlapping widths and different capacitance gaps is analyzed by the finite element software Ansoft Maxwell and ANSYS. The simulation values are compared with the theoretical values, which verifies that the fringe effect of capacitor must be considered when designing high precision capacitive inertial sensors. The simulated resonant frequency of the sensor is 616.19 Hz, the sensitivity is 0.659 μm/g, and accelerometer can sustain a shock acceleration of 1000 g, which proves the feasibility of the structure.