Enhancing the sensitivity of a mass-based piezoresistive micro-electro-mechanical systems cantilever sensor

A study on a fabricated piezoresistive micro-electro-mechanical systems (MEMS) cantilever for a mass-based sensor has been carried out to enhance sensor sensitivity by introducing the stress concentration region (SCR). Three types of SCR geometry designs were first analysed using finite element analysis (FEA) software ANSYS^?? to study the effect of stress and its distribution when varying mass is applied at the free end. FEA results show that the rectangular SCR design has the highest stress. Then, the length of rectangular SCR is varied from 1000 m (A1) to 3000 m (A3) to study the stress distribution along the cantilever. The piezoresistive MEMS cantilever with rectangular SCR A3 produced the highest stress and was thus selected for fabrication along with the piezoresistive MEMS cantilever without SCR. From the testing results, the piezoresistive MEMS cantilever with rectangular SCR A3 successfully enhanced sensitivity by 1.97 times as compared to the piezoresistive MEMS cantilever without SCR when varying mass is applied. Therefore this SCR approach appears to be suitable for enhancing the sensitivity of a mass-based piezoresistive MEMS cantilever sensor.