Optical detection of CH_3 during diamond chemical vapor deposition

Abstract

Measurements of CH_3 have been made using resonance-enhanced multiphoton ionization (REMPI) in two different diamond growth environments. Spatial profiles of methyl above the substrate have been measured in a filament- assisted reactor, which show that the CH_3 concentration is depleted near the substrate. The CH_3 concentration at the substrate shows an approximate Arrhenius dependence on substrate temperature below 1000 K, characterized by an activation energy of 4 kcal/mole. Methyl measurements were also made in 35 Torr hydrogen/oxygen flame into which methane is injected near the substrate. Radial profiles of methyl, acquired using REMPI, and of CH_4, acquired using sampling mass spectroscopy, are in good qualitative agreement with the results of numerical simulations.

Additional Information

© 1994 Society of Photo-Optical Instrumentation Engineers (SPIE). 17 June 1994. This work has been supported, in part, by the National Science Foundation under Grant CTS-9057921 and by the 17. J. Warnatz, in Combustion Chemistry, edited by W. C. Office of Naval Research, under contract N00014-90-J-1386. Gardiner, Jr. (Springer-Verlag, New York, 1984), p. 197. An additional equipment grant from the AT&T Foundation is gratefully acknowledged.

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