Fabrication and Characterization of a Novel Nanoscale Thermal Anemometry Probe

The development, fabrication, and characterization of a novel nanoscale thermal anemometry probe (NSTAP) for measuring velocity fluctuations in turbulent flows are described. This miniature MEMS anemometer consists of a freestanding 30 or 60 × 1 × 0.1 μm platinum filament with electrically conductive pads and a silicon structure. A novel deep reactive ion etching lag-based process for fabricating a 3D silicon support structure is described together with other microfabrication steps. The sensors behave similarly to conventional hotwire anemometers, with an order of magnitude better spatial and temporal resolution. Batch fabrication allows a relatively low-cost high-yield process, which together with its superior frequency response and size, make it an attractive thermal anemometry sensor for velocity measurements in turbulent flows.