Micro-pellistor with Integrated Porous Alumina Catalyst Support

Micro-pellistors capable to detect hydrocarbons below 50 mW power consumption at 550 oC operation temperature were developed by a novel processing technique. On the top of the full membrane type micro-heaters 1.4 μm thick porous alumina was formed by laterally selective electrochemical etching of the deposited aluminum layer. The porous alumina of the active element is selectively covered by finely dispersed Pt catalyst using alternative methods; such as dropping of H2[PtCl6] and sputtering technique, all aiming at deposition of controlled volume and structure of the catalyst. Constant current method in a Wheatstone-bridge configuration was applied in functional tests.