Batch-processed vacuum-sealed capacitive pressure sensors

This paper reports two multitransducer vacuum-sealed capacitive barometric pressure sensors, one using single-lead and the other using multiple-leads to transfer the electrical signal out of the vacuum-sealed reference cavity. The first device operates with a resolution of 37 mtorr over a pressure range from 600 to 800 torr. The sensitivity is 27 fF/torr (3000 ppm/torr). The TCO at 750 torr is 3900 ppm//spl deg/C and the TCS is 1000 ppm//spl deg/C. The second device has a resolution of 25 mtorr over a range from 500 to 800 torr, with individual transducer sensitivity of 39 fF/torr. The TCO at 750 torr is 1350 ppm//spl deg/C and TCS is 1000 ppm//spl deg/C. Both devices have an on-chip compensation capacitor and are read out using an electronically-trimmed switched-capacitor charge integrator.