A batch-fabricated silicon capacitive pressure transducer with low temperature sensitivity

A batch-fabricated solid-state capacitive pressure transducer has been developed using silicon integrated-circuit technology. The fabricated devices exhibit a dynamic range of 350 mmHg and a pressure sensitivity of about 1100 ppm/mmHg. The temperature coefficient of zero-pressure offset is about +50 ppm/°C (less than 0.05 mmHg/°C) and the temperature coefficient of pressure sensitivity over the -20 to +50°C temperature span is about +275 ppm/°C (less than 0.04 mmHg/°C) when the device is used with an open or vacuum-sealed reference cavity. These temperature coefficients are substantially lower than those of previously reported monolithic devices and are low enough that expensive temperature trims can be eliminated for many applications.