Design and fabrication of sculptured diaphragm MEMS low range pressure sensor

Abstract

In this paper the MEMS pressure sensor with sculptured diaphragm is designed, fabricated and tested for measuring low pressure range (0 - 600mbar). The classical flat diaphragm sensors give rise to linearity error and offset drift problem when it is used for wide range of temperature. If the offset drift and linearity error is high then compensation of the sensor with external electronics also becomes very tedious process and impossible in some cases. So, in this paper initially simulation study is discussed to optimize the sculptured diaphragm structure dimensions, to measure low pressure like 600mbar for the wide temperature range from -40°C to 80°C. COMSOL simulator tool is used to estimate the stress values on the diaphragm, and use these values to analytically determine the sensor output for different temperatures. With this simulation approach, the effect of temperature on the zero offset drift and linearity is studied. Based on the simulated structure, the diaphragm and resistor dimensions are decided and the optimized structure is fabricated using SOI wafer technology in clean room and tested for the same specifications. Finally, the simulated and practically obtained results are discussed and compared.