AeroMEMS pressure sensor with integrated wall hot-wire

Design, fabrication, and characterization of novel MEMS pressure sensors featuring integrated wall hot-wire sensors and sealed through silicon vias with back side bond pads are presented. Sensor chips are realized by silicon micromachining. They consist of a highly sensitive piezoresistive pressure sensor featuring a sensitivity of 4 μV/(VPa) and a wall hot-wire composed of aluminum (AlSiCu) that is thermally insulated by an air-filled cavity. Thus, the sensors make combined wall pressure and wall shear stress measurements possible. Integration of sealed through silicon vias enables to electrically contact the sensor chips from the back side. Hence, flow disturbing bond wires on the front side are avoided when chips are mounted flush with the measured surface. The sensor’s excellent dynamic properties and its potential of simultaneously measuring wall pressure and wall shear stress makes the device a powerful measurement tool for fluid mechanics.