Ceramic meso hot-plates for gas sensors

A new type of gas sensor is presented that combines the advantages of micro machined silicon gas sensors and ceramic gas sensors. Low temperature co-fired ceramics (LTCC)-technology, which is the cutting edge for manufacturing high density integrable circuits for high frequency applications, is used to manufacture gas sensors. The sensor devices are shaped like already known hot-plate low-power micro machined silicon gas sensors. Compared to classical ceramic gas sensors the low thermal conductivity (3 W/mK) leads to a low power consumption (480 mW at 330degreesC). The inexpensive manufacturing technology is a remarkable advantage for small series compared to the expensive silicon technology. This contribution presents first results for LTCC hot-plate gas sensors that include design, manufacturing, tests and simulation of such devices. Important thermal properties like power consumption and temperature distribution are measured and compared to FEM-simulations. The results of the simulations are used to improve the temperature distribution on the hot-plate. First measurements using a propane sensitive Cr2O3 layer show the principal operativeness of the concept using LTCC meso hot-plates for gas sensors. (C) 2004 Elsevier B.V. All rights reserved.