Design and simulation of MEMS based piezoresistive pressure sensor for enhanced sensitivity

The application of MEMS to the measurement of pressure is a mature application of micromachined silicon mechanical sensors. The present paper describes the design and simulation of surface micromachined piezo resistive type pressure sensor for enhanced sensitivity. The principle of the sensing mechanism is based on the deflection of sensing silicon nitride diaphragm. In order to achieve better sensor performance, a FEM analysis using mechanical analysis module of Intellisuite software is performed to evaluate the system output sensitivity of the pressure sensor. The deflections of the diaphragms (for square as well as circular) have been studied for different applied pressure. From this, the operating range as well as the sensitivity of the sensors can be easily determined. A detailed analysis of the deflection with different applied pressure is presented graphically. The output voltage and material elasticity of diaphragm are affected by temperature variations. So, use of heat sink is required for temperature compensation purpose. This simulation results depict that proper selection of the diaphragm geometry and piezoresistor location can enhance the sensor sensitivity with lower power consumption.