Simulation Analysis on Thermal Drift of MEMS Sandwich Accelerometer

Output stability over the entire temperature range is the key parameter to measure the performance of the accelerometer. The finite element models of the three MEMS sandwich accelerometers with different material combinations are established through ANSYS, on which the coupling field analysis is performed. The influence of the structural parameters on thermal drift under temperature load is quantized by fitting the curve of differential capacitance variation and its changing rate. The differential capacitance variation and its changing rate over the whole temperature range positively decreases with the increase of the thickness of the cap and substrate, and negatively increases with the increase of the thickness of the insulation layer. Using GOS film for the cap and substrate, and utilizing its thin glass layer for insulating layer is the optimal material combination to improving the thermal drift performance of the accelerometer. The influence of cap and substrate gradually weakens with the increase of thicknesses, when they get near to 500 mu m, continuing to increase the thickness has less impact on improving the performance of thermal drift.