Hostname: page-component-669899f699-2mbcq Total loading time: 0 Render date: 2025-04-29T23:24:21.791Z Has data issue: false hasContentIssue false
  • English
  • Français

Activity of tungsten and rhenium filaments in CH4/H2 and C2H2/H2 mixtures: Importance for diamond CVD

Published online by Cambridge University Press:  31 January 2011

M. Sommer  and
F. W. Smith
M. Sommer
Affiliation:
Department of Physics, The City College of the City University of New York, New York, New York 10031
F. W. Smith
Affiliation:
Department of Physics, The City College of the City University of New York, New York, New York 10031
Get access

Abstract

The resistance R, spectral emissivity ∊, and power consumption of W and Re filaments heated to 2500 °C in mixtures of CH4 or C2H2 in H2 have been measured in a series of experiments focusing on the state of the filament activity, i.e., its ability to dissociate the reactant gases. It has been found that these properties of the filaments, as well as the partial pressures of CH4 and C2H2 in the reaction chamber, depend critically on both the filament temperature and the reactant ratio, e.g., C2H2/H2. Specifically, both W and Re filaments show sharp jumps in power consumption at essentially the same temperature, signaling strong increases in filament activity and, hence, production of atomic hydrogen. These results are proposed to be due to the removal of nonreactive carbon from the surface of the filament via etching by atomic hydrogen and are consistent with the predictions of our thermodynamic model for the C–H system. Evidence for gas phase reactions is presented and the role of thermal diffusion is discussed. The emissivities of the W and Re filaments are observed to have significantly different temperature dependences which are attributed to differences in the phase diagrams for the W–C and Re–C systems. The implications of these results for hot-filament diamond CVD are discussed.

Type
Diamond and Diamond-Like Materials
Information
Journal of Materials Research , Volume 5 , Issue 11 , November 1990 , pp. 2433 - 2440
Copyright
Copyright © Materials Research Society 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

REFERENCES

1For a useful review, see Spear, K. E., J. Am. Ceram. Soc. 72, 171 (1989).CrossRefGoogle Scholar
2Langmuir, I. J. and Mackay, G. M. J., J. Am. Chem. Soc. 36, 1708 (1914).CrossRefGoogle Scholar
3Boudart, M., Ollis, D. F., and Harris, G.W., Trans. Faraday Soc. 65, 519 (1969).CrossRefGoogle Scholar
4Matsumoto, S., Sato, Y., Tsutsumi, M., and Setaka, N., J. Mater. Sci. 17, 3106 (1982).CrossRefGoogle Scholar
5Celii, F. G. and Butler, J. E., Appl. Phys. Lett. 54, 1033 (1989).CrossRefGoogle Scholar
6Sommer, M., Mui, K., and Smith, F.W., Solid State Commun. 69, 775 (1989).CrossRefGoogle Scholar
7Sommer, M. and Smith, F.W., to be published in High Temperature Science.Google Scholar
8Sommer, M. and Smith, F.W., Diamond, Boron Nitride, Silicon Carbide, and Related Wide Bandgap Semiconductors, edited by Glass, J.T., Messier, R. F., and Fujimori, N. (Mater, Res. Soc. Symp. Proc. 162, Pittsburgh, PA, 1989).Google Scholar
9Batty, J. C. and Stickney, R. E., J. Chem Phys. 51, 4475 (1969).CrossRefGoogle Scholar
10De Vos, J. C., Physica 20, 690 (1954).CrossRefGoogle Scholar
11Krikorian, O. H., Carpenter, J.H., and Newbury, R.S., High Temp. Sci. 1, 313 (1969).Google Scholar
12Barnes, B.T., J. Phys. Chem. 33, 688 (1929).CrossRefGoogle Scholar
13Jansen, F., Chen, I., and Machonkin, M. A., J. Appl. Phys. 66, 5749 (1989).CrossRefGoogle Scholar
14Toulukian, Y. S. and DeWitt, D. P., Thermophysical Properties of Matter (Plenum, New York, 1972), Vol. 8, p. 12.Google Scholar
15Moustakas, T. D., Solid State Ionics 32/33, 861 (1989).CrossRefGoogle Scholar
16 For an excellent review, see Rosner, D. E., Physico-Chemical Hydrodynamics 1, 159 (1980).Google Scholar
17Wu, C-H., Tamor, M.A., Potter, T. J., and Kaiser, E.W., in Diamond, Boron Nitride, Silicon Carbide, and Related Wide Bandgap Semiconductors, edited by Glass, J.T., Messier, R. F., and Fujimori, N. (Mater. Res. Soc. Symp. Proc. 162, Pittsburgh, PA, 1989).Google Scholar
18Pallmer, P. G. Jr., Gordon, R. L., and Dresser, M. J., J. Appl. Phys. 51, 1798 (1980).CrossRefGoogle Scholar
19Constitution of Binary Alloys, First Supplement, edited by Elliot, R. P. (McGraw-Hill, New York, 1965), C-Re on p.226; C-W on p.236.Google Scholar
20Bettler, P. C., Bennum, D. H., and Case, C. M., Surf. Sci. 44, 360 (1974).CrossRefGoogle Scholar