Evaluation of Output Signal Nonlinearity for Semiconductor Strain Gage with ANSYS Software

Abstract

The paper is devoted to the study of the nonlinearity of the output signal of the pressure sensor on the silicon on sapphire structure (SOS). The authors constructed a mathematical model of the strain-gauge and carried out numerical simulation by using the ANSYS 12.1 software. For comparative analysis, the problem was solved both in a geometrically nonlinear and in a geometrically linear formulation. To account for the elastic-plastic properties of the silver solder PSR72, the Prandtl diagram was used. As a result, the maximum stresses and deformations in the sapphire crystal, solder, and titanium membrane under which the design successfully works were determined, and also the nonlinearity of the output signal was estimated in depending of the applied pressure. According to calculations, the nonlinearity of the output signal is 11.3%. The received value is unacceptable for this type of sensor, and requires further tuning, which negatively affects the accuracy of the product and its cost.