HFCVD DIAMOND GROWN WITH ADDED NITROGEN - FILM CHARACTERIZATION AND GAS-PHASE COMPOSITION STUDIES

Citation
A. Afzal et al., HFCVD DIAMOND GROWN WITH ADDED NITROGEN - FILM CHARACTERIZATION AND GAS-PHASE COMPOSITION STUDIES, DIAMOND AND RELATED MATERIALS, 7(7), 1998, pp. 1033-1038
Citations number
27
Categorie Soggetti
Material Science
ISSN journal
09259635
Volume
7
Issue
7
Year of publication
1998
Pages
1033 - 1038
Database
ISI
SICI code
0925-9635(1998)7:7<1033:HDGWAN>2.0.ZU;2-C
Abstract
Recently there has been considerable interest in the addition of nitro gen to precursor gas mixtures and its influence on the properties of t he resulting diamond films. Careful control of the nitrogen concentrat ion in the CVD process results in changes to both the film growth rate and morphology. In addition to the well-defined and precisely control led deposition conditions, thorough characterization of the vapour-gro wn material is indispensable in order to tailor diamond film propertie s according to specific applications. High quality diamond films have been produced via hot filament CVD (HFCVD) using a precursor gas mixtu re of 1% methane in hydrogen with N-2 additions varying from 50 to 500 0 ppm (N/C 0.01-1.0). We report the results from both the structural a nd compositional characterization of the as-deposited HFCVD diamond fi lms by scanning electron microscopy, Raman spectroscopy and X-ray diff raction. Both the diamond phase purity and growth rate are maximized w ith 200 ppm N-2 in the gas mixture with further additions resulting in reduced growth rates and poorer film quality. We explain these findin gs in terms of the concentrations of gas phase species obtained from c hemical equilibrium calculations and in particular the importance of t he CN radical to the diamond growth process. (C) 1998 Elsevier Science S.A.