Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-25T17:26:39.375Z Has data issue: false hasContentIssue false

Simulation of Gas Phase Clustering of Nanocrystals in Sputter Discharges

Published online by Cambridge University Press:  28 February 2011

Seung J. Choi
Affiliation:
University of Illinois. Department of Electrical and Computer Engineering, 1406 W. Green St., Urbana, IL 61801
Mark J. Kushner
Affiliation:
University of Illinois. Department of Electrical and Computer Engineering, 1406 W. Green St., Urbana, IL 61801
Get access

Abstract

The preparation of nanocrystalline particles or clusters (sizes 1–50 nm) is of interest to the study of small systems and for use in sintering or compacting of high purity bulk materials. Recently, a method whereby these crystals can be fabricated using a sputter discharge has been reported. We have developed a computer model to simulate the formation of homogeneous (e.g., Si, Cu, Ti) gas phase clusters in these devices as precursors to larger nanocrystals. The model combines Monte Carlo and drift-diffusion algorithms to simulate the sputtering of atoms from the target, their thermalization in the buffer gas, and gas phase nucleation reactions. Densities of clusters having one to many hundreds of atoms are obtained as a function of position in the discharge. We find that the experimentally observed particle sizes cannot be explained by clustering involving solely neutral reactants due to their short residence times in the plasma. Negatively charged clusters which are trapped in the plasma have correspondingly longer residence times and most likely are responsible for the growth of large particles. Scaling laws for the growth of homogeneous clusters will be presented based on the results of the model.

Type
Research Article
Copyright
Copyright © Materials Research Society 1991

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.)

References

REFERENCES

1. Hahn, H. and Averback, R.S., J. Appl. Phys. 67. 1113 (1990).Google Scholar
2. Averback, R.S., Hahn, H., Höfler, H.J., Logas, J.C., and Shen, T.C., Mat. Res. Soc. Symp. Proc. 153, 3 (1989).Google Scholar
3. Birringer, R., Marquart, P., Klein, H.P., and Gleiter, H., Phys. Lett. 102A. 365 (1984).Google Scholar
4. Thomas, G.J., Siegel, R.W., and Eastman, J.A., Proc. Mats. Res. Soc. 153 13 (1989).Google Scholar
5. Birringer, R. and Gleiter, H., Encyclopedia of Mats. Sci. and Eng.,edited by Cahn, R.W. (Pergamon Press, Oxford. 1988) p.339.Google Scholar
6. Gleiter, H., Prog, in Mater. Sci. (1990) in press.Google Scholar
7. Karch, J., Birringer, R., and Gleiter, H., Nature 330. 556 (1987).Google Scholar
8. Mitchner, M. and Kruger, C., Partially Ionized Gases. (Willey, New York. 1973).Google Scholar
9. Meyer, K., Schuller, I.K., and Falco, C.M., J. Appl. Phys. 52. 5803 (1981).Google Scholar
10. Yidal, M.A. and Asomoza, R., J. Appl. Phys. 87. 477 (1990).Google Scholar
11. Phillips, J.C.. Chem. Rev. 86, 619 (1986).Google Scholar
12. Girshick, S.L. and Chiu, C.P., Plasma Chem. Plasma Proc. 9. 355 (1989).Google Scholar
13. Lai, F.S., Fiedlander, S.K., Pich, J., and Hidy, G.H., J. Colloid and Interface Science 39, 395 (1972).CrossRefGoogle Scholar
14. Gelbard, F., Tambour, Y., and Seinfeld, J.H., J. Colloid and Interface Science 76. 541 (1980).Google Scholar
15. Ulrich, G.D., Comb. Sci. Tech. 4. 47 (1971).Google Scholar
16. Haberland, H., in Fundamental Processes of Atomic Dynamics, edited by Birggs, J.S., Kleinpoppen, H., and Lutz, H.O. (Plenum, 1988).Google Scholar
17. Casero, R., Sainz, J.J., and Soler, J.M., Phys. Rev. A 37. 1401 (1988).Google Scholar
18. Echt, O., in Proc. 5th Svmp. on Atomic and Surface Physics, edited by Howorka, F., Lindinger, W., and Mark, T.D. (Obertraum, Austria, 1986).Google Scholar
19. Gai, H., Thompson, D.L., and Raff, L.M., J. Chem. Phys. 88. 156 (1987).Google Scholar