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Temperature-modulated micro-hotplate gas sensors

Conference ·
OSTI ID:441251
; ; ;  [1]
  1. National Inst. of Standards and Technology, Gaithersburg, MD (United States); and others

Using conventional CMOS (Complementary Metal Oxide Semiconductor) foundries, the authors have produced micro-hotplate structures consisting of an integrated heater, thermometer, and electrical contacts. Using the self-heating capabilities of the heater, sensor films were lithographically defined with controlled microstructure and electrical conductance. The sensing films were metal oxides such as SnO{sub 2} and ZnO, doped with catalytic additives, such as Pd, Pt, Ag, etc. The thermal time-constant of the device is 1 Ms, allowing temperature changes of greater than 10{degrees}C/s, over a temperature range to 550 {degrees}C in structures with Al, and 1000 {degrees}C without Al. Devices were tested in two systems: (1) an atmospheric test facility with computer controlled valves and flow controllers, and (2) an ultra-high vacuum system capable of supplying pure gases to the sensing surface.

OSTI ID:
441251
Report Number(s):
CONF-960782--
Country of Publication:
United States
Language:
English