An Electret-based Pressure Sensitive Mos Transistor

The operation of the Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is based on the fact that the lateral conductivity of silicon at the silicon dioxide-silicon interface strongly depends on the transverse electric field in the oxide. Adding a small air-filled spacer between metal gate and oxide, and applying a voltage across the insulator on top of the silicon, the lateral conductivity can become pressure sensitive. The generation of the electric field in the insulator can however also be provided by means of an electret. In this paper the integrated Electret-MOSFET based pressure sensor is presented with respect to its theory, realization and performance. .