Capacitive differential pressure sensor with high overload capability using silicon/glass technology

A capacitive pressure sensor for differential pressures of 100 kPa (1 bar) with an overload capability up to 25 MPa (250 bar) without the need for an external overload protection is presented. The sensing element consists of a Pyrex/silicon/Pyrex sandwich and is fabricated in silicon/glass technology using anodic bonding. To increase the overpressure range the sensor element is mounted in a pre-stressed mounting fixture, which was optimized numerically. Results of FEA simulations, technological processing and sensor performance are discussed.