Nonlinear analysis of a CMOS integrated silicon pressure sensor

This paper reports theoretical and experimental results of analysis on the nonlinear characteristics of a CMOS integrated pressure sensor with a square silicon diaphragm. It is shown that nonlinearity is caused by both the large diaphragm deflection and the nonlinear piezoresistance of the resistors. The optimum layout for the piezoresistors to minimize their nonlinearity is also shown. The measured nonlinearity for the fabricated device agrees well quantitatively with the numerically analyzed nonlinearity.