Robust Micromachined Silicon Carbide Environmental Sensors

50561-98-I Robust Micromachined Silicon Carbide Environmental Sensors--Boston MicroSystems Inc., 356 Walnut Street, Wellesley, MA 02181-3324; (617) 661-6075 Dr. Richard Mlcak, Principal Investigator Dr. Richard Mlcak, Business Official DOE Grant No. DE-FG02-98ER82541 Amount: $74,957 A strategic need exists for foul-resistant sensors capable of operating at elevated temperatures and chemically aggressive environments, characteristic of smokestacks and combustion exhausts, while exhibiting high sensitivity, selectivity to key emission constituents, and rapid response. In addition, the remote placement and monitoring of sensors requires low power drain and reasonable cost. This project will develop a unique, versatile, and robust micromachined single crystal silicon carbide sensor consisting of p-n junction active sensor elements and an integrated microhotplate. The sensor will be capable of operating in corrosive environments at elevated temperatures, with high selectivity, reproducibility, rapid response times, and low power dissipation. A patented photoelectrochemical micromachining process will be utilized to fabricate freestanding SiC microhotplates and single crystal SiC p-n junction active sensor elements. Tests will be conducted in controlled gaseous environments representative of combustion exhausts. Commercial Applications and Other Benefits as described by the awardee: The sensors should be useful for monitoring, controlling, and tracking smoke stack and combustion exhaust emissions, essential for insuring compliance with clean air regulations. The sensors could also be used for monitoring the geographic dispersal of emissions in varying climatic conditions._