AVS 46th International Symposium
    The Science of Micro-Electro-Mechanical Systems Topical Conference Wednesday Sessions
       Session MM-WeA

Paper MM-WeA3
Deposition, Characterization and Degradation of Vacuum-deposited Fluorinated Alkylsiloxane Films

Wednesday, October 27, 1999, 2:40 pm, Room 620

Session: Micro-Science and Tribology
Presenter: T.M. Mayer, Sandia National Laboratories
Authors: T.M. Mayer, Sandia National Laboratories
M.P. de Boer, Sandia National Laboratories
N.D. Shinn, Sandia National Laboratories
T.A. Michalske, Sandia National Laboratories
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We deposit monolayer films of fluorinated alkylsiloxanes by a chemical vapor deposition process using C@sub 8@F@sub 13@H@sub 4@SiCl@sub 3@ and H@sub 2@O. Films are formed under well controlled conditions of reactant exposure and temperature, from 25 - 300@super o@ C. Using in-situ ellipsometry and quartz crystal microbalance techniques, we show that film thickness is self limiting at approximately one monolayer due to coverage dependent adsorption of precursors. Adhesion measurements of micromechanical structures coated with these films show typical adhesion energies of ~20 µJ/m@super 2@ at low humidity conditions. Exposure to high humidity environments for long periods results in degradation of the films and stronger adhesion. We postulate that this degradation is related to defects in the films, which are susceptible to hydrolysis by adsorbed water. We examine this postulate by measuring adhesion for varying film coverage, and by examining the morphology of freshly deposited and aged films by atomic force microscopy. Friction measurements correlated to film structure and history are examined as well in micromechanical test devices using structures coated with these films.