Temperature Stabilized MEMS Capacitor for Inertial Sensing Application

This paper presents a proposed method to stabilize the open loop scale factor of a gyroscope against environmental effects (particularly temperature variation) with experimental results. This is achieved by applying electronic feedback to control the DC bias across a MEMS capacitor that is to be used in the gyroscope charge sensing amplifier, thereby stabilizing against temperature variations. In this work, a MEMS cantilever capacitor design was used, and the capacitance change was differentially sensed through two pads located underneath the MEMS cantilever beam. A controlled DC bias voltage was then applied to electrostatically return the capacitance to its initial value. Results show that differential changes in capacitance may accurately sense down to 10s of ppm.