Integration of a sensitive material to a silicon-based device for CO detection

A sensitive semiconductor oxide has been successfully integrated to a silic on-based prototype of sensor for environment pollution as CO. The sensitive material SnO2 includes catalyst Pd aggregates and provides a low temperatu re detection (80-120 degrees C) by conductance change (sensitivity S = (G - G(0))/G(0) = 60 at 120 degrees C for 50 ppm CO in air in steady state and S = 8 in dynamic regime). The (100) silicon substrate, coated by a Si3N4 in sulating film, includes a micro-heater, a temperature measuring resistor, a nd Pt interdigital electrodes, covered with the sensitive material integrat ed using a Ultrasonic Submicronic Aerosol Pyrolysis process at atmospheric pressure. The operating cycle of the system has been studied, regarding to the necessity to reactivate the sensitive material at regular intervals by heating at higher temperature. (C) 1999 Elsevier Science S.A. All rights re served.