Theoretical and experimental studies of micromachined hot-wire anemometers

A new type of micromachined and batch-fabricated hot-wire anemometers has been developed. The systematic characterization of these devices, especially of the steady-state characteristics, frequency response, and directional dependence are presented. These micromachined anemometers can perform better than conventional ones because of their extremely small size. It is demonstrated that a 10 µm long, 1 µm wide, and 0.5 µm thick polysilicon hot wire can have a unprecedented bandwidth of 1.4 MHz in constant-temperature mode.