Abstract
In this paper a method of analyzing the nonlinear characteristics of a piezoresistive semiconductor pressure sensor and the results given by this method are described.
The main causes of nonlinearity in a semiconductor pressure sensor are the nonlinear characteristics of the piezoresistive effect in silicon and of the stress in the silicon diaphragm. Experimental data are used to derive a nonlinear characteristics formula and then the formula is used to estimate the nonlinearity of the piezoresistive effect. Approximate formulas for uniformly loaded circular plates with a large deflection are also used to calculate the nonlinearity of the stress in a silicon diaphragm.
Using these formulas, it is shown that the nonlinearity error of a pressure sensor is related to the positions of radial and tangential resistors on the silicon diaphragm. Optimum resistor positions, in which nonlinearities are less than 0.2% F. S., have also been determined.
