Design of Capacitive Micro-Electro-Mechanical-Systems (MEMS) Accelerometer, Considering Residual Stress, Temperature Variations and Thermoelastic Damping

Abstract

This paper presents the design of two capacitive MEMS accelerometers while following two different fabrication process constraints. The first accelerometer is designed according to the design specifications of Silicon-on-Insulator Multi-User MEMS Processes (SOIMUMPS) fabrication process and the second design follows the MEMS Integrated Design for Inertial Sensors (MIDIS) fabrication process. The focus of this study is to design a dual axis capacitive MEMS accelerometer with low cross-axis sensitivity and high reliability. The effect of thermoelastic damping and residual stresses is observed on the proposed design and its temperature range of -40 to 100 °C is characterized. The operating bandwidth of designed accelerometers is 0- 400 Hz with operating acceleration of ±15 g for design 1 and ±50 g for design 2. The FEM simulations of these devices is performed in ANSYS and CoventorWare. The capacitive sensitivities of design 1 and 2 are 31.5 fF/g and 38 fF/g respectively.