Home | News | Publications | Contact Information | Links

Search Site Bioactive Surfaces formed by Low Energy Electron Beam Lithography of Self-Assembled Monolayers By Cindy Harnett Patterned amine-terminated self-assembled monolayers (SAMs) have potential as a template for the deposition and patterning of a wide variety of materials on silicon surfaces, including biomolecules. Amine SAMs may be electron-beam patterned by direct exposure to the beam, or by backfilling an electron-beam patterned inert monolayer. This page describes direct low-energy electron-beam patterning of 2-aminopropyltriethoxysilane (APTS) and (aminoethylaminomethyl)phenethyltrimethoxysilane (PEDA) self-assembled monolayers on silicon substrates. Self-assembled monolayers have been studied as a resist or template-making material for use in microcolumn electron-beam lithography systems. Microcolumn arrays are limited to low voltages (around 1000 V) because small gaps between their microfabricated parts may cause electrical arcs at higher voltages. APTS monolayers are formed on silicon by immersion for 15 minutes in a dilute APTS/methanol solution. PEDA monolayers are formed by 20 minute immersion in dilute PEDA/methanol. The electron beam is used to diminish the reactivity of monolayers in the exposed areas. Exposure damages or removes the amine groups which are responsible for adhesion to other materials. When an exposed APTS or PEDA monolayer is immersed in a solution of particles that attach to amines, the particles adhere preferentially to the unexposed areas.   Next page: Detecting changes in electron-beam exposed regions