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Proceedings Paper

Direct measurement of H-atom sticking coefficient during diamond film growth
Author(s): L. Robbin Martin
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Paper Abstract

In previous work it has been demonstrated that diamond thin films can be grown in a heated quartz flowtube by adding organic molecules to a stream of atomic hydrogen. In this system, the pattern of diamond film growth may be used to obtain information about the growth kinetics. In the present work, a thin, moveable catalytic probe that detects hydrogen atoms has been added. Since the flowtube is at a uniform temperature and has a high flowspeed, the rate of decay of H-atoms down the tube may be converted to a sticking coefficient, after making a small correction for diffusive mass transfer. The data were taken at a tube temperature of 800 Celsius and a pressure of 3.7 torr, with 1 SCCM of methane injected into a flow of 150 SCCM of 90% argon, 10% hydrogen. Calibration of the H-atom probe indicates that all the hydrogen is initially nearly dissociated. The probe measurements give a sticking coefficient at 800 Celsius of about 3 X 10-4 for the silicon/diamond substrates. During diamond deposition, i.e., when methane is flowing, the apparent sticking coefficient rises to 2.5 X 10-3, although this includes the effect of gas phase reaction as well as wall loss. We will discuss how these numbers shed light on proposed mechanisms for diamond formation.

Paper Details

Date Published: 1 December 1991
PDF: 8 pages
Proc. SPIE 1534, Diamond Optics IV, (1 December 1991); doi: 10.1117/12.48290
Show Author Affiliations
L. Robbin Martin, The Aerospace Corp. (United States)

Published in SPIE Proceedings Vol. 1534:
Diamond Optics IV
Albert Feldman; Sandor Holly, Editor(s)

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