Scanning probe nanofabrication of chemically active areas on substrate covered with organosilane monolayers

An organosilane monolayer self-assembled onto Si substrates was patterned using a scanning tunneling microscope or an atomic force microscope with a conductive probe. The tip-scanned area was etched by wet etching, while the unscanned area remained resistant to the etching. Consequently, the tip-scanned patterns were transferred to the substrate Si using the scanned area as an etching window. Moreover, the tip-scanned area preferentially reacted with other organosilane molecules, e.g., 3-aminopropyltrimethoxysilane, to form a monolayer confined to the scanned pattern. Next, onto this amino-terminated monolayer, aldehyde-modified latex nanoparticles were immobilized area selectively through chemical reaction between the amino and aldehyde groups. It was demonstrated that in the areas where the probe tip of the microscopes had been scanned, the surface was terminated with hydroxyl groups and became active to various chemical treatments. © 1997 American Vacuum Society.