A batch-processed vacuum-sealed capacitive pressure sensor

This paper reports a multi-transducer vacuum-sealed capacitive barometric pressure sensor. The device operates with a resolution of 25 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 3969 ppm//spl deg/C and the TCS is about 1000 ppm//spl deg/C. The device uses a single layer of polysilicon both for sealing to the glass and for transfer of the glass electrode in the reference cavity to the outside world. The device is read out using a switched-capacitor charge integrator and an on-chip compensation capacitor.