Structure mechanics analysis on three-axis piezoresistive micro accelerometer

A three-axis piezoresistive accelerometer based on SOI with single mass and four side-eight beam structure was designed to improve the mechanical precision and the consistency of silicon process. The accelerometer detected three-axis acceleration signals by connecting the resistances on the beams to form three Wheatstone bridges. The mathematics model was established by using the theory of Mechanics of Material and Mechanics of Vibration,and the systemic mechanics analysis of the structure was made. The results indicate the influence of the structure parameters on the performance such as intrinsic frequency and sensitivity of three directions. The static and modal simulations were carried out by ANSYS software,which proved the correctness of the mechanics analysis. Finally,the processing flows were designed,and the unpacked accelerometer was showed. The micro-accelerometer can test three-dimensional vector simultaneously,and the design of Wheatstone bridge and structure restrain the transverse effect effectively.