Sensitivity enhancement in piezoresistive micro-pressure sensor using perforated diaphragm

Abstract

MEMS is the science of miniaturization which creates tiny-integrated devices. The piezoresistive pressure sensors because of its high sensitivity and linearity, ease of fabrication is mostly used in wide variety of applications. To enhance the sensitivity of the conventional piezoresistive pressure, the diaphragm is made perforated. The diaphragm in the non-stress area is made porous to reduce the mass of the device. Mechanical stiffness of the perforated diaphragm when subjected to pressure induces more stress comparatively. The pores of size 40μm×40μm are made in the diaphragm of size 400μm×400μm. The percentage of porous area is varied from 0 to 40% and results are compared. The designed models are simulated using COMSOL Multiphysics. The simulated results reveal that Sensor with 40% perforation is highly sensible to applied pressure and shows extended linearity. The sensitivity of the sensor with 40% perforation achieves 49.6mV/V/MPa where as conventional sensor is 42mV/V/MPa.