A Piezoresistive Pressure Sensor with Optimized Positions and Thickness of Piezoresistors

In this paper, a piezoresistive pressure sensor based on silicon on insulator (SOI) was presented, which was composed of an SOI layer with sensing elements and a glass cap for a hermetic package. Different from its conventional counterparts, the position and thickness of the four piezoresistors was optimized based on numerical simulation, which suggests that two piezoresistors at the center while the other two at the edge of the pressure-sensitive diaphragm and a thickness of 2 mu m can produce the maximum sensitivity and the minimum nonlinearity. Due to the use of silicon rather than metal for electrical connections, the piezoresistive pressure sensor was fabricated in a highly simplified process. From the experimental results, the fabricated piezoresistive pressure sensor demonstrated a high sensitivity of 37.79 mV center dot V-1 center dot MPa-1, a high full-scale (FS) output of 472.33 mV, a low hysteresis of 0.09% FS, a good repeatability of 0.03% FS and a good accuracy of 0.06% FS at 20 degrees C. A temperature coefficient of sensitivity of 0.44 mV center dot MPa-1 center dot degrees C-1 and a low zero drift were also shown at different temperatures. The piezoresistive pressure sensor developed in this study may function as an enabling tool in pressure measurements.

Automated summary

This paper presents a piezoresistive pressure sensor based on SOI, with optimized design for increased sensitivity and reduced nonlinearity. The sensor is fabricated in a simplified process and shows high sensitivity, low hysteresis, good repeatability and accuracy in different temperature environments.