A study on offset drift with temperature of MEMS inertial sensors

This paper presents a detailed study of offset drift of a capacitive inertial sensor with temperature. The goal is to analyze the contribution to the overall drift component by the sensor and the signal conditioning circuit. The relevance of the study lies in the fact that the offset drift with temperature affects the overall accuracy of the sensor. The device selected for the case study is a bulk micro-machined single axis inclinometer with differential capacitive sensing mechanism. To assess the temperature dependence of capacitance, a numerical analysis has been done. Finite element method is used to simulate thermal, electrostatic and electro-thermo mechanical behavior of the sensor assembly. Simulations are performed to understand the advantages of silicone material based mounting technique, where a silicone based encapsulant is used to attach sensor to package. An experimental approach to segregate the offset drift contribution has been proposed.