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 hot-wire 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.