SILICON ETCHING DURING THE HFCVD DIAMOND GROWTH

Citation
Jc. Arnault et al., SILICON ETCHING DURING THE HFCVD DIAMOND GROWTH, JOURNAL OF PHYSICAL CHEMISTRY B, 102(25), 1998, pp. 4856-4864
Citations number
42
Categorie Soggetti
Chemistry Physical
Journal title
JOURNAL OF PHYSICAL CHEMISTRY B
ISSN journal
15206106 → ACNP
Volume
102
Issue
25
Year of publication
1998
Pages
4856 - 4864
Database
ISI
SICI code
1089-5647(1998)102:25<4856:SEDTHD>2.0.ZU;2-H
Abstract
The silicon etching that occurs during the CVD diamond growth has been investigated as a function of the methane content in the gas phase by SEM and AFM in the tapping mode on pristine Si(lll) surfaces. Size, d epth, and angular distributions of the etch pits were recorded. We evi dence the strong effect of the carbon content on the etching process. The silicon etching is slightly increased with addition of 0.1-0.25% o f methane in the feed gas, and depletes with larger addition of carbon . This etching occurs easily along Si(100) directions. This is explain ed by the better stability on (100) planes of the precursor SiH2 to re move silane than on (111) planes. A modelization of the process points out the balance between the drop of the atomic hydrogen concentration in the gas phase and the inhibition of hydrogen bulk diffusion into s ilicon when increasing the methane content and covering the surface wi th carbon. This explains the occurrence of a maximum of silicon etchin g. Possible consequences on the diamond nucleation process are then pu t forward. It is thus expected that the etching of the silicon is gene rally detrimental as generating low-density silicon surface such as Si (100) where diamond nucleation is inhibited.