Analysis and Optimization of Sensitivity of a MEMS Peizoresistive Pressure Sensor

Abstract

This paper presents a MEMS Piezoresistive pressure sensor which utilizes a circular shaped polysilicon diaphragm with a nanowire to enhance the sensitivity of the pressure sensor. The polysilicon nanowire is fabricated in such a way that it forms a bridge between the circular polysilicon diaphragm and the substrate. The high Piezoresistive effect of Silicon nanowires is used to enhance the sensitivity. A circular polysilicon nanowire piezoresistor was fabricated by means of reactive ion etching. This paper describes the performance analysis, structural design and fabrication of piezoresistive pressure sensor using simulation technique. The polysilicon nanowire pressure sensor has a circular diaphragm of 500nm radius and has a thickness about 10nm. Finite element method (FEM) is adopted to optimize the sensor output and to improve the sensitivity of the circular shaped diaphragm of a polysilicon nanowire Piezoresistive pressure sensor. The best position to place the Polysilicon nanowires to receive maximum stress was also considered during the design process..The fabricated polysilicon nanowire has high sensitivity of about 133 mV/VKPa.