AVS 53rd International Symposium
    Surface Science Thursday Sessions
       Session SS-ThP

Paper SS-ThP29
Optimization of Lithographic Parameters for Writing Thiolated Molecules via Nanografting and NPRW using an Open-Loop AFM System

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Surface Science Poster Session
Presenter: W. Serem, Louisiana State University
Authors: W. Serem, Louisiana State University
J.N. Ngunjiri, Louisiana State University
J.C. Garno, Louisiana State University
Correspondent: Click to Email
The unique advantages and capabilities of nanografting and NanoPen Reader and Writer (NPRW) for writing arrays of nanopatterns (< 200 nm) of self-assembled monolayers (SAMs) using an open-loop AFM system will be presented. Both methods apply force to an AFM tip to write SAM nanopatterns in ambient environments. Nanografting is accomplished in a dilute solution of the molecules chosen for writing. The AFM tip is scanned at high force, displacing molecules of the matrix SAM under the tip. Fresh molecules from solution assemble onto the surface following the track of the scanning tip. For NPRW, the AFM tip is coated with SAM molecules for writing in air or water. During writing, the tip is scanned at a high force to write nanopatterns within a methyl-terminated matrix SAM resist. For both methods, the resolution of writing depends on the geometry of the AFM tip, easily achieving 10 nm dimensions with standard commercial cantilevers. Nanografting and NPRW are excellent for in situ studies and use the same tip for fabrication and imaging the designed nanostructures. Both methods offer flexibility and can be used to write n-alkanethiols with different terminal chemistries and chain lengths. When using an open-loop AFM scanner, the writing speed, direction and force must be optimized to achieve high-resolution writing. Vector movements which translate the tip in both the X and Y directions simultaneously are shown to produce problems with alignment and registry for nanopatterns. We will disclose the programming strategies for tip translation which lead to improvements in the uniformity, alignment and geometries of nanopatterns written using open-loop feedback control.