A combined piezoresistive/capacitive pressure sensor with self-test function based on thermal actuation

A new pressure sensor combining a piezoresistive and a capacitive measurement principle is described. Both the mechanical stress in a thin silicon diaphragm as well as the deflection are measured. The sensor has the additional feature that its operation can be checked by means of a thermal actuator, integrated in the device. Applying electrical power to a heater results in an internal pressure rise, allowing the sensor output to be checked and eventually adjusted. Experimental results on sensor operation and self-test actuation are presented and discussed.