Capacitive pressure sensor with minimized dielectric drift

Abstract From the Canadian patent

Pressure sensors utilizing capacitance variations to sense pressure variations of the silicon on-silicon type in which dielectric drift, which occurs in such sensors due to the changing characteristics primarily of the dielectric wall support layer (16) extending up from the silicon substrate (12) between it and the silicon diaphragm (11) is, minimized by in turn minimizing the contribution of the dielectric layer to the total capacitance of the sensor (10), reducing the dielectric contribution to the capacitance from, for example, about fifty (50%) percent down to a range of no more than about twenty to twenty-five (20-25%) percent and down typically to sixteen to about ten (16%-10%) …