AVS 49th International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP3
Stability Studies of Monolayers on Scribed Silicon to Water, Air, and X-ray

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Surface Science Poster Session
Presenter: G. Jiang, Brigham Young University
Authors: G. Jiang, Brigham Young University
T.L. Niederhauser, Brigham Young University
S.D. Davis, Brigham Young University
M.R. Linford, Brigham Young University
Correspondent: Click to Email
The stability of alkyl monolayers on scribed silicon to air, water, and/or X-rays was investigated. Monolayers were prepared by scribing silicon surfaces in the presence of reactive liquids (1-pentene, 1-decene, 1-hexadecene, methyl iodide, 1-iodopetane, 1-iododecane, 1-butanol, 1-bromopentane, and 1,4-dibromobutane) with a computer-controlled diamond-tipped instrument. In all cases some initial oxidation of the underlying silicon surface was observed by X-ray photoelectron spectroscopy (XPS), which increased with time until the O1s/Si2p XPS ratio reached a stable level (after 100 - 200 hours). In the case of silicon scribed under the iodoalkanes, the iodine to silicon ratio by XPS decreased with time until it also reached a stable value. The C1s/Si2p XPS ratios for all surfaces remain essentially constant after all exposures to air and water, which indicates that monolayers of 1-alkenes and 1-haloalkanes on scribed silicon are quite stable. Kinetics measurements using water contact angles on scribed patches and water capacity measurements of hydrophobic corrals on silicon show trends similar to the XPS results. In general, hydrophobic corrals retained much of their capacity to hold water. Surface oxidation is shown to take place at the silicon surface. It is suggested that iodine is lost by hydrolysis of surface Si-I bonds. Finally, no change in the amount of C, O, or Br at the surfaces was observed by XPS after 3 - 4 hr of illumination with monochromatic Al Ka X-rays, indicating that XPS analyses can be performed on monolayers on scribed silicon without substantially damaging them.