Characteristics research of pressure sensor based on nanopolysilicon thin films resistors

Abstract

To further improve the sensitivity temperature characteristics of pressure sensor, a kind of pressure sensor taking nanopolysilicon thin films as piezoresistors is proposed in this paper. On the basis of the microstructure analysis by X-ray diffraction (XRD) and scanning electron microscope (SEM) tests, the preparing process of nanopolysilicon thin films is optimized. The effects of film thickness and annealing temperature on the micro-structure of nanopolysilicon thin films were studied, respectively. In order to realize the measurement of external pressure, four nanopolysilicon thin films resistors were arranged at the edges of square silicon diaphragm connected to a Wheatstone bridge, and the chip of the sensor was designed and fabricated on a [Formula: see text] orientation silicon wafer by microelectromechanical system (MEMS) technology. Experimental result shows that when [Formula: see text] = 6.80 mA, the sensitivity of the sensor PS-1 is 0.308 mV/kPa, and the temperature coefficient of sensitivity (TCS) is about −1742 ppm/[Formula: see text]C in the range of −40–140[Formula: see text]C. It is possible to obviously improve the sensitivity temperature characteristics of pressure sensor by the proposed sensors.