This paper discusses the temperature dependence of the nonlinearity in silicon diaphragm piezoresistive pressure sensors. Minimization of the temperature dependence is very important in designing high-precision pressure sensors which can be used over the wide temperature range. The amount of temperature dependence can be evaluated quantitatively by using the non-linear characteristics formula of the piezoresistive effect in p-type silicon diffused layers. From the characteristic analysis of silicon diaphragms in {110} and {100} planes by this method, the following results are derived. (1) The amount of the temperature dependence of the non-linear error increases in proportion to the increase in strain added on the silicon diaphragm. (2) Optimum gauge pattern which minimizes the non-linear error and its temperature dependence is found to exist on the {110} plane.
Using these results, high-precision semiconductor pressure sensors are developed. The specifications are as follows: (1) The nonlinear error is less than ±0.1%. (2) The output voltage is larger than 65mV/V. (3) The operating temperature range is between-40°C and 120°C.
