Temperature Dependence of Non-Linear Characteristics in Semiconductor Pressure Sensors

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.