AVS 49th International Symposium
    Plasma Science Tuesday Sessions
       Session PS2-TuA

Paper PS2-TuA3
Abrupt Changes with Mixture Composition in the Surface Coverage and Etch Rate During Si Etching by Cl@sub 2@-Ar Plasmas

Tuesday, November 5, 2002, 2:40 pm, Room C-105

Session: Plasma Surface Interactions I
Presenter: I.P. Herman, Columbia University
Authors: N.C.M. Fuller, Columbia University
I.P. Herman, Columbia University
V.M. Donnelly, University of Houston
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Laser desorption of the adlayer, with laser-induced fluorescence and plasma-induced emission detection of the desorbed adsorbates, has been used to investigate Si etching in inductively coupled Cl@sub 2@-Ar plasmas. These techniques show that the relative coverage of SiCl@sub x@ species and etch rate increase and the coverage of Si decreases very abruptly as the chlorine fraction is increased for a 75% Cl@sub 2@ plasma with the bias set for 80 eV ions. The Cl@sub 2@ fraction required to produce this abrupt change increases with an increase in ion energy. There is no corresponding abrupt change in the Cl, Cl@super+@, and Ar@super+@ densities or electron temperature at this mixture condition, as measured by optical emission spectroscopy. The implications of these results and the reaction mechanism will be discussed. This work is supported by NSF Grant No. DMR-98-15846.