Design and Fabrication of Micromachined Gas Sensors

With the advent of microfabrication technology, efforts have been made to make miniaturized gas sensor. This paper describes the use of micromachining technology in the design and fabrication of closed-membrane-type gas sensor. Micromachined gas sensors consist of an active area that comprises a platinum (Pt) heater, interdigitated gold (Au) electrodes and a gas sensitive layer (tin oxide) situated at the centre of a thin membrane which itself is supported by an outer frame of silicon (micro- heater). The micromachined gas sensors comprise the advantages of microsize, structures in identical, highly uniform, and low power consumption. The micromachined gas sensor developed initially to determine carbon monoxide (CO), with later application to others gases.