Performance analysis of a silicon piezoresistive pressure sensor based on diaphragm geometry and piezoresistor dimensions

摘要

Micro Electro Mechanical System (MEMS) based silicon pressure sensors were the first micro mechanical transducers developed. They have undergone a significant growth in the last few years. In this paper the different shapes of diaphragms (rectangular, square and circular) having the same surface area and thickness has been investigated. Performance parameters like the maximum induced stress and deflection of the diaphragms have been compared using the finite element tool Coventor Ware®. In addition to that, the effect of the size of the piezoresistor which forms the whetstone bridge of the sensor, on the sensitivity has been studied and reported. There are four resistors diffused in to the diaphragm in such a way that two of them are arranged parallel to the membrane edge (Group-A) and the other two are arranged perpendicular to the edge (Group-B). The simulation results clearly indicate that the dimension of Group-B resistor plays an important role in determining the sensitivity of the pressure sensor.