Design of High Sensitivity SOI Piezoresistive MEMS Pressure Sensor

In this paper, the effect of the size of the piezoresistors that forms the Wheatstone bridge on sensitivity has been studied and reported. There are four resistors implanted on the diaphragm in such a way that two of them sense the tensile stress (Group I) and the other two senses the compressive stresses (Group II). The structure of this MEMS sensor has been created and analyzed using IntelliSuite MEMS CAD tool. The results show that the size of the group I resistors should be made as large as possible and that of group II should be made as small as possible to achieve maximum sensitivity. It is also illustrated that the size design of group II resistors is critical.