AVS 46th International Symposium
    Nanometer-scale Science and Technology Division Monday Sessions
       Session NS1-MoA

Paper NS1-MoA1
Tribological Properties of Self-Assembled Monolayers on Si Surfaces

Monday, October 25, 1999, 2:00 pm, Room 612

Session: Nanoscale Tribology and Adhesion
Presenter: J.E. Houston, Sandia National Laboratories
Authors: J.E. Houston, Sandia National Laboratories
J.D. Kiely, Sandia National Laboratories
J.A. Mulder, University of Minnesota
X.-Y. Zhu, University of Minnesota
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The use of organic monolayers as lubricating films has recently received considerable attention, especially with regard to their potential use in micromachine applications. We have used the interfacial force microscope (IFM) to characterize, on the nanometer scale, the tribological properties of a new class of self-assembled monolayers on Si(001) surfaces. These films consist of alkyl-OH and NH2 terminated molecules reacted with a fully chlorinated Si surface. We contrast their tribological behavior with those of the more familiar alkylchlorosilane monolayers through measurements of contact hysteresis, lateral frictional force and film conductance as a function of normal load. In addition, we probe the wear behavior under repetitive "wear-track" cycles. The chlorosilane monolayers show high friction coefficients and considerable wear while the films grown on the chlorinated surface show low friction coefficients and little wear, suggesting that the latter has considerable potential as a monolayer lubricant for Si. We discuss these results in terms of what is known concerning the structural and chemical properties of these two types of self-assembled monolayers. This work was supported by the U.S. Department of Energy under contract DE-AC04-94AL85000. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U.S. Department of Energy.