SILICON CAPACITIVE PRESSURE SENSOR

摘要

A capacitive pressure sensor uses two silicon wafers hermetically sealed to each other by recrystallized silicon formed by the migration of a ring of silicon-aluminum eutectic material from the wafer interface to the surface of one wafer. Within the ring of the eutectic a cavity with opposing conductive plates forms a capacitor. Another high conductivity path through the wafer can be formed simultaneously with the ring of eutectic material by placing an aluminum dot on the interior side of one silicon wafer. Thus, a high conductivity path is available through a silicon wafer for each of the two capacitor plates.