Rapid thermal processing of mesoporous silica films: A simple method to fabricate films micrometers thick for microelectromechanical systems (MEMS) applications

We are interested in constructing self-assembled mesoporous silica films several micrometers thick in a cost-effective way, for use as ionic conductors, membranes, and sensors for microelectromechanical systems (MEMS) applications. One way to construct films of micrometer thickness is to repeat the coating processes with each step, followed by calcination of the surfactants. However, conventional furnace calcination requires hours, which makes it impractical. In this paper, we report the use of a lamp-based rapid thermal processing (RTP) as a simple and fast way to remove surfactants and stiffen the silica framework. The RTP enabled us to save processing time (by an order of magnitude, in comparison to the time required for conventional furnace processing). Mesoporous silica films similar to 2.5 mu m thick were fabricated within an hour. Using microfabrication techniques, self-supporting mesoporous films were subsequently fabricated on patterned silicon wafers.