Sensitivity enhancement of a silicon based MEMS pressure sensor by optimization of size and position of piezoresistor

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 effect of the size of the piezoresistor which forms the whetstone bridge of the sensor, on the sensitivity has been studied and reported. In addition to that the proper positioning of the resistor on the diaphragm has been analyzed. 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. Sensitivity can be improved by optimization of resistor size or by proper positioning of the resistor on the diaphragm.