A High-resolution Area-change-based Capacitive MEMS Accelerometer for Tilt Sensing

Abstract

This paper reports a newly developed chip-level micro-electromechanical system (MEMS) accelerometer for tilt sensing based on differential array area-change capacitive displacement transducer and through-silicon-wafer etching process. The proposed MEMS accelerometer consists of a silicon-based acceleration-sensitive spring-mass structure, a upper glass cover plate and an universal capacitive readout application specific integrated circuit (ASIC) die, which is used to apply differential driving signals and pickup capacitance change due to area-variation under in-plane motion. The MEMS accelerometer has a linear measurement range of ±30° with a scale factor of 33.6 mV/°. The tilt measurement resolution of the MEMS accelerometer is evaluated by the modified Allan deviation with the results showing that an angle resolution of 0.003° at an integral time of 3 seconds. Compared with the commercial MEMS tilt sensors, the proposed MEMS accelerometer in this work has a larger full measurement range and a larger bandwidth but a little bit poor linearity. Hence, it is believed that the proposed chip-level MEMS accelerometer is promising to be a high-resolution tilt sensor with a lower power consumption and smaller volume.