Analysis of the Temperature Dependence of a Semiconductor Pressure Sensor

Abstract

This paper describes an analysis of the temperature characteristic of piezoresistive semiconductor pressure sensors and its improvement. In this analysis the non-linear temperature dependence of thermal expansion of silicon is considered to calculate the thermal stress in the silicon diaphragm. The temperature characteristic of the sensor is then calculated considering the non-linearity of piezoresistive coefficients for temperature. This analysis reveals that the temperature characteristic strongly depends on the difference in thermal expansion between the silicon diaphragm and its mounting die. The appropriate dimension of the mounting die which minimizes this thermal stress is calculated and a trial pressure sensor is manufactured. The trial pressure sensor with a compensating circuit consisting of thermisters and resisters shows a good temperature characteristic; the zero point change and the span change are less than±1% for temperature range -40∼120°C.