Thermally compensated silicon pressure sensor

摘要

A semiconductor pressure sensor employing the piezoresistive effect of single crystal silicon resistors to measure the flexure of a semiconductor diaphragm. In the preferred embodiment, a Wheatstone bridge composed of a first pair of resistors disposed on the center of the diaphragm and a second pair of resistors disposed on the periphery of the diaphragm is employed. Due to the nature of the diaphragm flexure, the first and second pairs of resistors exhibit piezoresistivity in opposite directions enabling pressure measurement with greater sensitivity. The diaphragm is mounted on and supported by a silicon clamp ring. The diaphragm and the clamp ring together form a unitary semiconductor structure. Because the piezoresistive effect which serves as a measure of the diaphragm flexure and hence as a measure of the pressure difference across the diaphragm is temperature dependent, the sensor also includes a temperature sensitive resistor, forming a part of the same unitary semiconductor structure, which provides a measure of the temperature of the piezoresistive elements. This measure of temperature enables external circuitry to correct for the temperature dependence of the piezoresistive effect thereby providing a pressure measurement of greater accuracy.