Micropatterning of Ceramics on Substrates towards Gas Sensing Applications

摘要

There is an ongoing interest to widen the range of materials into the fabrication of Microelectromechanical Systems (MEMS). Ceramic powders in gas sensor fabrication facilitate the use of a wide range of complex oxide compositions compared to gas phase processes such as chemical (CVD) and physical vapour deposition (PVD). Miniaturization of thick film gas sensors offers advantages like integration on the logical chip and low heat consumption. Transition metal-doped tin oxide is widely known for its use as gas sensitive material in both thick and thin film sensor technologies. We used soft lithography, namely micromolding in capillaries (MIMIC) for the fabrication of micro-structured tin oxide ceramics on different substrates. Colloidal dispersions of fine ceramic powders were successfully applied in MIMIC similar to techniques using metallorganic ceramic precursors. The attained feature size strongly depends on the powder size but on the preparation of the colloidal suspension as well. Using 0.25 micron oxide powder, structures of 10 microns and below were well reproduced.