Design Issues of Piezoresistive MEMS Accelerometer for an Application Specific Medical Diagnostic System

This paper reports the design and simulation of finite element method (FEM)-based micro-electro-mechanical-systems (MEMS) piezoresistive accelerometer used in a strapdown medical diagnostic system. A square proofmass with four flexures is used in this design. Here, p-doped single-crystal silicon are used as eight piezoresistors implanted on the flexures for sensing the maximum stress; and they are connected in the form of a wheatstone bridge with each arm containing two piezoresistors. Basically, here two different geometric configuration but of same material have been designed and simulated using FEM-based tool for dynamic range (±)2g. To assure better performance characteristics, different analysis for both the configurations are done. Configuration 1 is found to have better performance with respect to load withstanding capability, eigen value analysis, better response characteristic, and low cross-axis sensitivity. Furthermore, the measurement scheme adopted is the wheatstone bridge, which gives better performance as offset is almost nullified.