Design and Simulation of MEMS Pressure Sensor Using COMSOL Multiphysics Tool and Analysis of its Compatibility with Digital Interfacing Unit for Pressure Measurement

Abstract

This paper summarizes variation of characteristic which arises from the longitudinal change of stress that induced in
the sensor circuit main part or the p-type Si piezoresitive element with respect to induced stress. This sensing or
conversion of stress to analog voltage resulted from the piezeoresistive effect occurred within the sensor when stress
applied. The location of the sensor on the membrane surface has chosen near to the fixed edge of the plate where
maximum stress exits. The p- Si piezoresistive sensor has included in readout circuit configuration as one of the two
elements in the sensor circuit and the other one of them placed in a stress-free region that is on the fixed edge with the
same orientation. This circuit configuration is chosen to generate readable analog sensor output voltage which is
simple and convenient to make both analytical and computer-aided analysis. Since the two sensing elements used in
the sensor circuit are identical, in absence of pressure the output voltage is found to be nearly half of the biasing
voltage. And also we observed that the sensor output voltage linearly varies with the applied pressure at the center of
the diaphragm. Finally, the change in output voltage per one 100kPa pressure is calculated in the longitudinal
orientation. We have determined that this resolution is matched with 8-bit analog to digital converter’s output
resolution if suitable signal conditioning circuit is employed for pressure measurement purpose.