摘要 |
<p>A capacitive absolute pressure sensor (10) includes a substrate (14) having an electrode (24) deposited thereon, and a diaphragm assembly (12) disposed on the substrate (14). As pressure increases, the diaphragm (16) deflects, touches the electrode (24) (in the touch mode), and changes the capacitance of the sensor (10). The changed capacitance is sensed to thus sense pressure changes. A burried feedthrough is used to sense the change in a capacitance in a chamber (34) under the diaphragm (16) and thus determine the pressure sensed. A vacuum in the chamber (34) is maintained by proper selection of a thickness of a sensing electrode and an insulating layer (32), exposition thereof to a thermal cycle, and the hermetic bonding of the diaphragm assembly (12) to the substrate (14). <IMAGE></p> |