Development of a hydraulically smooth wall shear stress sensor utilizing through silicon vias

Abstract

This paper describes the development of a wall shear stress sensor system designed to be fully non-invasive to low-speed aerodynamic flows. The microelectromechanical systems (MEMS) sensor is fabricated with integrated through-silicon-vias (TSVs), eliminating the need for front side wire bonds. Packaged in a modular housing with interchangeable components, the result is a device with less than 50 μm of deviation over the wetted surface, satisfying the requirements of hydraulic smoothness for flow speeds less than 30 m/s. Sensor performance includes a sensitivity of 1.36 mV/Pa at 1.128 kHz, corresponding to a minimum detectable signal of 1.1 mPa, resonance of 3.4 kHz with a 1.5 kHz flatband, and 72 dB of pressure rejection.