A Novel Semiconductor Piezoresistive Thin-Film Strain Gauge With High Sensitivity

Abstract

Strain sensors are essential to structural health monitoring technology. Currently, commercially available strain gauges exhibit limitations such as weak output signal, temperature sensitivity, nonlinearity, instability, and difficulties in mass production; however, the ever-expanding application scenarios of strain gauges have sparked a heightened demand for enhanced sensitivity and testing accuracy in strain detection. In this work, a novel, highly sensitive semiconductor strain sensor is developed and manufactured via the MEMS process. The sensor employs dopant silicon as its sensitive material, while its design ingeniously integrates silicon-sensitive grids to amplify the gauge factor (GF) and output signal. Through the implementation of a differential output structure, the temperature dependence of the semiconductor resistor can be mitigated. A platinum temperature resistor is, furthermore, integrated to compensate for the impact of temperature variations on the measurement caused by changes in silicon Young’s modulus. The sensor exhibits a nonlinear error of less than 0.5% within the range of 0– 196 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu ~\varepsilon$ </tex-math></inline-formula> , and it possesses a GF of 174, which is approximately 80 times greater than that of existing commercial strain gauges. The proposed sensor exhibits significant performance enhancements and holds promising potential for industrial applications in highly demanding structural health monitoring scenarios.