A SUBMICRON PARTICLE FILTER IN SILICON

A multi-purpose screen filter structure in silicon has been fabricated and characterized. The fabrication of the filter structure is based on a two-step self-aligning process using lateral boron doping, anisotropic silicon etching and silicon dioxide undercut etching. Filters for filtration of particles down to 50 nm have been fabricated. The flow resistance for gases and liquids has been measured. The fluid passes between two electrically conducting membranes, so other applications such as fluid identification and concentration measurements are possible. A preliminary fluid identification experiment is presented. © 1990.