Evaluation of the Accuracy of Out-of-Plane Normal Stress Detection Using Novel Piezoresistive CMOS Sensors

This paper discusses the measurement opportunities arising from a novel piezoresistance sensor featuring vertical currents. Temperature-compensated measurements of a sum of the three normal stress components including the vertical normal stress, are presented. In specific applications with sensors located at free surfaces where the vertical normal stress component vanishes, a combination of this temperature-compensated measurement and a pseudo-Hall measurement yields the individual in-plane normal stresses. Furthermore, the temperature-uncompensated extraction of the vertical normal stress component is discussed with respect to the new measurement possibilities provided by the presented sensor. A sensitivity analysis illustrates the influence of individual uncertainty sources to the overall uncertainty of the measurement. Based on these results possible improvements in stress detection are suggested.