SiC Based Pressure Sensor for High-Temperature Environments

Aim of the work presented herein is to develop a SiC based pressure sensor enabling measurements up to 3000 bar at temperatures in the range of 25degC to 400degC. For fabrication of the sensor chip various processing techniques potentially permitting effective membrane structuring are compared. The sensor chip features a centerboss membrane with four piezoresistors made from epitaxial layers. To limit movement of the centerboss, a bottom plate wafer made from SiC is bonded to the sensor chip. The bottom plate is thus acting as an overpressure safety feature. A tungsten-based metallization scheme tested up to 500degC is used. The housing of the sensor is fluid-free and employs a steel membrane for media separation.