Sensitivity Analysis of Rectangular Microcantilever Structure with Piezoresistive Detection Technique Using Coventorware FEA

Abstract

Micro Electro Mechanical Systems (MEMS) based microcantilever is a micromachined device similar to the miniaturized version of a diver's board, longer as compared to width, and has a thickness much smaller than its length or width. The merits of MEMS microcantilever sensors are its high sensitivity, design simplicity, portability and high speed. In this paper, a microcantilever sensor is designed to meet the requirements of a biosensor that detects tuberculosis. The addition of mass on the microcantilever surface makes it to bend and its stressed elements deform.The deflection underwent by microcantilever is detected by piezoresistive detection mechanism. The behavior of piezoresistive microcantilever structure is investigated using various beam materials and geometric dimensions. The advantage of incorporating SCR (Stress Concentrated Region) on the piezoresistive microcantilever is studied and the optimal position of placing the piezoresistor on the microcantilever beam is investigated using load analysis and corresponding stress distribution results. CoventorWare® is used to do the analysis of micromachined cantilever. The results show that sensitivity increases with increase in length and incorporation of SCR but decreases with increase in thickness.