Silicon compatible materials for harsh environment sensors

The wide bandgap semiconductors silicon carbide and diamond and the material system Silicon On Insulator (SOI) are compared regarding their suitability as silicon compatible materials to extend the application fields of micromachined sensors to harsh environment conditions especially to high temperatures. The harsh environment conditions are specified by analyzing the demands of automotive and aerospace applications. The physical properties of the material systems are discussed and their technological stage of development is evaluated, especially with respect to the compatibility to standard silicon processes. Furthermore, the commercial availability of the different materials in the form of substrates is considered and a forecast of future developments is attempted. As an example of a harsh environment sensor, a combustion pressure sensor is presented and characterized.