Improved Reproducibility in Porous Silica Sol-Gel Processing Using Tertiary Butanol Solvent
A.K. Rissanen, M. Blomberg and H. Kattelus
VTT Technical Research Centre of Finland, FI
Keywords: sol-gel, aerogel, xerogel, TBA, porous film patterning
Silica aerogels and xerogels are porous materials, which possess many exceptional properties. The research for the use of aerogel thin films in MEMS applications, such as humidity sensors, biosensors and calorimetric devices, is still at an early stage. Therefore the aerogel thin film process development is prerequisite. Previously, highly volatile liquids like ethanol or isopropanol (IPA) have been used for the solvent in the traditional two-step acid-base sol-gel process, which may deteriorate the reproducibility of the process. In this paper, a novel method to produce porous films with improved reproducibility is presented. It is also demonstrated that aerogel films act as a source for particles during the supercritical drying process. Aerogel patterning with lithography and plasma etching is investigated.
Nanotech 2004 Conference Technical Program Abstract