Design and Simulation of Digital Output MEMS Pressure Sensor

Abstract

This paper presents the design and simulation of a MEMS pressure sensor with a digital output for measuring pressure in the range of 0–1 bar. The sensor uses the diaphragm deflection and a simple mechanical structure to convert the applied pressure to a logic digital output. Three different designs of the sensor have been proposed with square and circular diaphragms. The first design uses ten different sized square diaphragms on the same substrate to get a resolution of 0.1 bar. The second design uses a single square diaphragm instead of ten to get the same resolution. The third design also uses a single circular diaphragm with a central boss structure, which reduces the deflection nonlinearity at low pressures. Analytical analysis was carried out for all the diaphragm deflections, and the results are supported by numerical simulations carried out in COMSOL Multiphysics tool. The proposed sensor can operate on 5 V which suits well with conventional CMOS logic. The direct digital output from the pressure sensor makes its useful in wide variety of applications.