AVS 47th International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP37
1-to-9 keV Electron-Induced Surface Chemistry in Ultra High Vacuum Systems

Tuesday, October 3, 2000, 5:30 pm, Room Exhibit Hall C & D

Session: Poster Session
Presenter: Q. Ma, Argonne National Laboratory
Authors: Q. Ma, Argonne National Laboratory
R.A. Rosenberg, Argonne National Laboratory
Correspondent: Click to Email
Electrons in accelerators are ubiquitous. They range in energies from MeV down to a few eV (secondary electrons). Collisions of these electrons with surfaces of accelerator components may produce reactions that will modify the properties of the surface/vacuum interface. In order to gain insight into these reactions, we have studied the interaction of 1-to-9 keV electrons with the Ar-ion sputtered surfaces of Al, TiN, and Si, under ultra high vacuum conditions using scanning Auger electron spectroscopy. Electron-induced surface chemistry takes place on all these surfaces. For both Al and Si, layer-by-layer growth of oxides was produced by electron beam bombardment. In the case of Al, a clear threshold behavior of the oxidation rate is observed for excitation energies near the Al K-core hole (1560 eV), which suggests participation of secondary electrons in the surface reaction. In the case of TiN films, surface carbonation occurred with 9 keV electron bombardment while no reaction was observed with 5 keV el ectrons. No enhancement of the surface oxidation rate was observed. It will also be shown that the deposited carbonaceous layer is graphitic in nature, resulting in a decrease of the secondary electron yield and thus an increase of the observed sample current. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences under Contract No. W-31-109-ENG-38.