IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Nanometer Structures Wednesday Sessions
       Session NS+EL-WeA

Paper NS+EL-WeA7
Micro and Nanoscale Patterning of SAMs and Their Functionalisation

Wednesday, October 31, 2001, 4:00 pm, Room 133

Session: Molecular Electronics and Patterning
Presenter: S. Sun, University of Manchester Institute of Science and Technology, UK
Authors: S. Sun, University of Manchester Institute of Science and Technology, UK
K. Chong, University of Manchester Institute of Science and Technology, UK
G.J. Leggett, University of Manchester Institute of Science and Technology, UK
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Lithography methods are at the heart of modern-day microfabrication, nanotechnology and molecular electronics. These methods always rely on patterning of a resistive film followed by a chemical etching of the substrates. Self-assembled-monolayers (SAMs) of alkanethiols on metals (Au, Ag or Cu) have been found to be good resists to protect underneath metals from wet etching. In addition, due to the chemical reactivity of some groups on SAMs, various kind of materials can be immobilized onto it. Therefore patterning and functionalisation of SAMs have attracted great interest since the last decade. Various methods have been employed for this purpose. Here we report experiments that generate micro- and nanometer size patterns of SAMs. Micrometer size features have been obtained through masked photo-oxidation either by a high-pressure mercury arc lamp or a lamp that only emits 254 nm light. Proteins have been immobilised onto these features successfully and can exhibit both a lateral force and topography contrast. Nanometer scale patterns have been achieved by scanning alkanethiol coated atomic force microscope (AFM) tips across Ag/Au film surface, a method called dipped-pen-nanolithography (DPN). It has been found the transportation rate of alkanethiols from AFM tip to metal surface not only depend strongly on the humidity of the environment, but also on the quantity of alkanethiol adsorbed on the tip and properties of substrate of interest. Different feature sizes from several micrometers to less than 50 nm have been obtained by controlling the scan speed and the environment humidity. Similar with the SAMs on Au, the SAMs on Ag formed by this method can also be used as resist layer to protect underneath Ag film from chemical wet etching.