Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-05T21:10:26.545Z Has data issue: false hasContentIssue false
  • English
  • Français

Development of Ultra-Clean Plasma Deposition Process

Published online by Cambridge University Press:  15 February 2011

Toshihiro Kamei  and
Akihisa Matsuda
Toshihiro Kamei
Affiliation:
Thin Film Silicon Solar Cells Superlab, Electrotechnical Laboratory, 1-1-4 Umezono Tsukuba 3058568, Japan
Akihisa Matsuda
Affiliation:
Thin Film Silicon Solar Cells Superlab, Electrotechnical Laboratory, 1-1-4 Umezono Tsukuba 3058568, Japan
Get access

Abstract

We have developed a new type of ultra-high vacuum plasma-enhanced chemical vapor deposition (UHV/PECVD) system. According to high sensitivity secondary ion mass spectrometry, device quality hydrogenated amorphous silicon (a-Si:H) films deposited at 250°C at a deposition rate of 1 Å/s contains 1015 cm-3 of O, 1015 cm-3 of C, and 1014 cm-3 of N impurities, while low defect hydrogenated microcrystalline silicon (μc-Si:H) films deposited at 200°C at a very low rate of 0.1 Å/s include 1016 cm-3 of O, 1015 cm-3 of C and 1016 cm-3 of N. These are the lowest concentrations of atmospheric contaminants for these kinds of materials observed so far. The essential features of the present UHV/PECVD system are an extremely low outgassing rate of 8×10-9 Torr·s, extremely low partial pressure of contaminant gas species <10-12 Torn, and purification of feed gas SiH4 at “point of use”. These efforts are quite important not only for clarifying the microscopic mechanism of photo-induced degradation in a-Si:H, but also for enlarging the crystalline grain size in μc-Si:H. μc-Si:H with a grain size of ≍1000 Å as determined by Scherrer's formula can be obtained at the higher rate of 1.5 Å/s by utilizing a VHF (Very High Frequency) plasma. The specific origins of impurities in the films are also discussed.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 557: Symposium A – Amorphous and Heterogeneous Silicon Thin Films—Fundamentals to Devices—1999 , 1999 , 19
Copyright
Copyright © Materials Research Society 1999

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

1. Tsai, C. C., Knights, J. C., and Thompson, M. J., J. Non-Cryst. Solids 66, 45 (1984).Google Scholar
2. Tsuda, S., Takahama, T., Isomura, M., Tarui, H., Nakashima, Y., Hishikawa, Y., Nakamura, N., Matsuoka, T., Nishiwaki, H., Nakano, S., Ohnishi, M., and Kuwano, Y., Jap. J. Appl. Phys. 26, 33 (1987).Google Scholar
3. Tanaka, H., Koyama, M., Miyachi, K., Ashida, Y., Ohashi, Y., Fukuda, N., and Nitta, A., in Proceedings of the 4th International Photovoltaic Science and Engineering Conference (The Institution of Radio and Radio Electronics Engineers Australia, New South Wales, Australia, 1989).Google Scholar
4. Kroll, U., Meier, J., Keppner, H., Shah, A., Littlewood, S. D., Kelly, I. E., and Giannoules, P., J. Vac. Sci. Technol. A13, 2742 (1995).Google Scholar
5. Kamei, T., Hata, N., Matsuda, A., Uchiyama, T., Amano, S., Tsukamoto, K., Yoshioka, Y., and Hirao, T., Appl. Phys. Lett. 68, 2380 (1996).Google Scholar
6. Redfield, D. and Bube, R. H., Phys. Rev. Lett. 65, 464 (1990).Google Scholar
7. Redfield, D. and Bube, R. H., J. Non-Cryst. Solids 137&138, 215 (1991).Google Scholar
8. Fritzsche, H., J. Non-Cryst. Solids 190, 180 (1995).Google Scholar
9. Kamei, T., Kondo, M., and Matsuda, A., Jpn. J. Appl. Phys. 37, L265 (1998).Google Scholar
10. Kamei, T. and Matsuda, A., J. Vac. Sci. Tech. A 17, 113 (1999).Google Scholar
11. Knights, J. C., in The Physics of Hydrogenated Amorphous Silicon I, edited by Joannopoulos, J. D. and Lucovsky, G. (Springer, Berlin, 1984), Vol. 55, p. 5.Google Scholar
12. Oda, S., Noda, J., and Matsumura, M., Jpn. J. Appl. Phys. 29, 1889 (1990).Google Scholar