Design and Simulation of PolySi Diaphragm Capacitive Pressure Sensor

This paper presents the design and simulation of a capacitive pressure sensor system for industrial and biomedical applications. Employing the Micro Electro Mechanical Systems (MEMS) technology, high sensor sensitivities and resolutions have been achieved. This report provides initial data on the design and simulation of such a sensor. The sensor is composed of a polysilicon diaphragm that deflects due to pressure applied over it. Applied pressure deflects the 2 µm diaphragm changing the capacitance between the Silicon substrate and the polysilicon diaphragm.  The pressure sensor provides a linear change in capacitance versus pressure in the range of 0.1MPa to 1MPa. The simulation result shows a displacement of 0.25µm / 0.1MPa of the diaphragm and capacitance of 30fF to 44fF in the linear region.