Simulation of a Low Frequency Z-Axis SU-8 Accelerometer in CoventorWare and MEMS+

This paper presents the simulation of a z-axis SU-8 capacitive accelerometer. The study consists of a modal analysis of the modeled accelerometer, a study relating capacitance to acceleration, capacitance to deflection, an effective spring constant calculation, and a comparison of results achieved using CoventorWare® ANALYZER and MEMS+®. A fabricated energy harvester design from [1] was used for modeling and simulation in this study, with a four spring attachment of a 650µm × 650µm × 110µm proof mass of 4.542×10-8kg. At rest, the spacing between electrodes is 4µm along the z-axis, and at 1.5g acceleration, there is 1.9µm spacing between electrodes, at which point pull in occurs for a 1V voltage.