AVS 50th International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS1-WeA

Paper PS1-WeA10
Reactive Surface Coefficients for Radicals in a Vacuum Beam System

Wednesday, November 5, 2003, 5:00 pm, Room 314

Session: Mechanisms in Plasma-Surface Interactions
Presenter: Y. Kimura, University of California, Berkeley
Authors: Y. Kimura, University of California, Berkeley
J. Coburn, University of California, Berkeley
D. Fraser, University of California, Berkeley
H. Winters, University of California, Berkeley
D.B. Graves, University of California, Berkeley
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We present direct measurements of reactive surface coefficients for various radicals on a range of surfaces. The reactive surface coefficients are determined using the Radical- and Ion-Surface Interaction Analysis System (RISIAS). RISIAS is equipped with two external radical sources and an external ion beam source, all of which can be simultaneously trained on a surface. A threshold ionization quadrupole mass spectrometer (TIQMS) is aligned with one of the radical beam’s line of sight to measure radical flux in the beam. After measuring the radical flux, the TIQMS is vertically translated to allow insertion of a sample surface into the beam path via a load lock. With the sample surface in place, reflected radicals are measured with the TIQMS through a separate aperture. Choppers are used for background subtraction, allowing a direct measurement of the incident beam and reflected components. Experiments conducted with a temperature-controlled quartz crystal microbalance allow measurements of net deposition or etching with various beam components on a range of surfaces. The beam-to-background ratio of the radical beam in the TIQMS is measured to be 15 for the direct line of sight, and about 1 for reflected radicals. RISIAS can measure reactive surface coefficients from ~ 0.01-1. Measurements of CF@sub 3@, CF@sub 2@, CF, NH, NH@sub 2@, F and O radicals reacting with stainless steel, silicon, silicon dioxide, hydrocarbon and fluorocarbon surfaces will be presented.