Abstract
Using a mass spectrometric sampling method, we have observed the decomposition of CH4 in an rf plasma usedfor diamond deposition. The gas samples were extracted through an orifice located downstream of the plasma zone and analyzed online. For the experiments a dilute mixture of H2 and CH4 containing 0.1–3% CH4 has been used. CH4 is converted to C2H2 and C2H4 quantitatively. Small amounts of heavier hydrocarbons are formed. A comparison of the experimental results with a recent kinetic model treating a purely thermal environment is made and the differences between our experiment and the model are explained. The role of acetylene as a species formed in an atmosphere rich in atomic hydrogen is proposed. The electron impact dissociation process is suggested as the rare-determining step in the plasma-chemical decomposition of methane.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
D. V. Fedoseev, S. P. Vnukov, and B. V. Deryagin,Zh. Fiz. Khim. 50, 2751 (1976) (in Russian); translated inRuss. J. Phys. Chem. 50, 1645 (1976).
D. V. Fedoseev and V. P.Varnin,Zh. Fiz. Khim. 57, 2726 (1983) (in Russian); translated inRuss. J. Phys. Chem. 57, 1647 (1983).
M. Tsuda, M. Nakajima, and S. Oikawa,J. Am. Chem. Soc. 108, 5780 (1986).
M. Frenklach and K. E. Spear,J. Mater. Res. 3, 133 (1988).
D. Huang, M. Frenklach, and M. Maroncelli,J. Phys. Chem. 92, 6379 (1988).
I. Chen,J. Appl. Phys. 64, 3742 (1988).
M. Sommer, K. Mui, and F. W. Smith,Solid State Commun. 69, 775 (1989).
J. A. Mucha, D. L. Flamm, and D. E. Ibbotson,J. Appl., Phys. 65, 3448 (1989).
J. Matsui, A. Juuki, M. Sahara, and Y. Hirose,Jpn. J. Appl. Phys. 28, 1718 (1989).
Y. Lifshitz, S. R. Kasi, and J. W. Rabalais,Mater. Res. Soc. Symp. Proc. 128, 101 (1989).
S. J. Harris and A. M. Weiner,J. Appl. Phys. 67, 6520 (1990).
K. Kobashi, K. Nishimira, Y. Kawate, and T.Horiuchi,Phys. Rev. B 38, 4067 (1988).
M. Frenklach,J. Appl. Phys. 65, 5142 (1989).
S. J. Harris, D. N. Belton, A. M. Weiner, and S. J. Schmieg,J. Appl. Phys. 66, 5353 (1989).
W. L. Hsu,J. Vac. Sci. Technol. A6, 1803 (1988).
D. V. Fedoseev and J. N. Tolmachev,Izv. Akad. Nauk SSSR, Ser. Khim., No. 6, p. 1180 (1979) (in Russian).
G. Jansen, W. J. P. van Enckevort, and L. J. Giling,Proc. Ist Int. Symp. Diamond, 1989,Proc. Electrochem. Soc. 89-12, 508 (1989).
P. A. Karaev and F. K. Huseinova,Azerb. Khim. J. No. 4, p. 11 (1986) (in Russian).
T. Chen, R. Avni, J. D. Winefordner, and H. Nickel, Pyrolysis of Methane by Microwaves,Ber. Kernforschungsanlage Jülich, No. 1188 (1975).
S. J. Harris and A. M. Weiner,Appl. Phys. Lett. 53, 1605 (1988).
S. J. Harris,J. Appl. Phys. 65, 3044 (1989).
F. G. Celii, P. E. Pehrsson, H.-t. Wang, and J. E. Butler,Appl. Phys. Lett. 52, 2043 (1988).
F. G. Celii and J. E. Butler,Appl. Phys. Lett. 54, 1031 (1989).
F. G. Celii, P. E. Pehrsson, H.-t. Wang, H. H. Nelson, and J. E. Butler,Proc. 1st International Conference on New Diamond Science and Technology, Tokyo, 1988.
D. Heim, G. Moser, J. Laimer, and H. Störi,Proc. 9th Int. Symp. Plasma Chemistry, R. d'Agostini, ed., Pugnochiuso, Italy (1989), Vol 1, p. 452; full details in: C. Heim, Ionenextraktion aus Hochfrequenzplasmen, Diplomarbeit Technische Universität Wien, 1989, Vienna, Austria.
K. R. Doolan and J. C. Mackie,Combust. Flame 50, 29 (1983).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Okeke, L., Störi, H. Plasma-chemical decomposition of methane during diamond synthesis. Plasma Chem Plasma Process 11, 489–499 (1991). https://doi.org/10.1007/BF01447161
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01447161