The surface loss probability β of CH3 radicals on a-C:H surface is determined by time-resolved threshold ionization mass spectrometry in pulsed RF discharges. In the post-discharge, the β value decreases from 0.011-0.015 to 0.001-0.002 in about 10ms. This time evolution suggests that the loss probability depends on incoming ion and radical fluxes on the surface. We present a simple model of the surface reaction kinetics in which the number of active chemisorption sites on the surface is determined by the balance between their production, due to ions and/or H, and their annihilation, due to CH3 radicals. The model describes fairly well the observed decay of the CH3 radical density and the time evolution of β determined experimentally in the afterglow. The maximum contribution of the CH3 radicals to the deposition rate of a-C:H films was deduced to be about 60% of the total deposition rate determined experimentally.
|Number of pages||4|
|Journal||Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers|
|Issue number||7 SUPPL. B|
|Publication status||Published - Jul 1997|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)