Design of a Dual-Axis Capacitive MEMS Accelerometer for Low Cross-Axis Sensitivity and Low Noise using SOIMUMPs Process

Abstract

This work presents the design of a dual-axis electrostatic MEMS accelerometer to achieve low cross-axis sensitivity and low noise while considering the microfabrication constraints of commercially available multi-user SOIMUMPs process. The suspension beams are designed to minimize the cross-axis coupling and increase mechanical stability. The MEMS accelerometer design is optimized using a new optimization methodology to achieve robust dynamic response in the operating temperature range of −40 ᵒC to 100 ᵒC. The optimization methodology involves the use of integrated design and analysis of computer experiments, Gaussian process regression, desirability function approach and FEM simulations. The effect of temperature variations on the squeeze film air damping force in the electrostatic sensing combs and corresponding effect on the dynamic response is analyzed and considered in the optimization study. The voltage sensitivity of the proposed MEMS accelerometer design is obtained by the integration of accelerometer behavioral model with the readout electronics in the MATLAB Simulink environment. The input acceleration range for the proposed MEMS accelerometer design is ±25 g with cross-axis sensitivity less than 0.03 % and total noise equivalent acceleration (TNEA) value of 0.2 mg⁄√Hz.