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Microstructural Defects of Device Quality Hot-Wire Cvd Poly-Silicon Films

Published online by Cambridge University Press:  15 February 2011

J.K. Rath ,
F.D. Tichelaar  and
R.E.I. Schropp
J.K. Rath
Affiliation:
Debye Institute, Utrecht University, P.O.Box 80000, 3508 TA Utrecht, the Netherlands
F.D. Tichelaar
Affiliation:
Debye Institute, Utrecht University, P.O.Box 80000, 3508 TA Utrecht, the Netherlands
R.E.I. Schropp
Affiliation:
National centre for HREM, Rotterdamseweg 137, 2628 AL Delft, the Netherlands
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Abstract

Two types of poly-Si:H thin films made by Hot Wire CVD have been evaluated with respect to utilisation in solar cells. Poly-Si:H films made at high hydrogen dilution are highly porous and have large interconnected voids. The void density is 25000/μm-3 as determined by XTEM. On the other hand, poly-Si:H layers made at low hydrogen dilution have a compact structure and a much smaller density of voids. In these films, two types of voids exist: globular voids smaller than 15 nm, and elongated voids, often located between columns of large crystals of 150-250 nm wide at the top. The density for the 5 - 15 nm spherical voids is usually -50/μm3, but larger concentrations often occur locally, up to 1000/pm3, i.e., 0.05% volume fraction. High oxygen content in the poly-Si films made at high hydrogen dilution is largely due to post deposition intrusion of water vapour through the interconnected voids. Profiled layers are made by depositing device quality poly-Si:H layers (low hydrogen dilution) on top of a seed layer (high hydrogen dilution) of high nucleation density. Cells incorporating profiled poly-Si:H films as i-layers at a deposition rate of 0.5 nm/s were made on stainless steel substrates in the configuration SS/n-μc-Si:H(PECVD)/i-poly-Si:H(HWCVD)/p-μc-Si:H(PECVD)/ITO. For our n-i-p solar cell with poly-Si i-layer we obtained an efficiency of 4.41% and a FF of 0.607. Due to native surface texture a current density of 19.95 mA/cm2 is generated in only ~1.22 μm thick i-layer without back reflector.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 557: Symposium A – Amorphous and Heterogeneous Silicon Thin Films—Fundamentals to Devices—1999 , 1999 , 573
Copyright
Copyright © Materials Research Society 1999

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References

1. Meier, J., Torres, P., Platz, R., Dubail, S., Kroll, U., Selvan, J.A. Anna, Vaucher, N. Pellaton, Hof, Ch., Fischer, D., Keppner, H., Shah, A., Ufert, K.-D., Giannaoules, P., Koeler, J., in “Amorphous Silicon Technology-1996”, Edited by Hack, M., Schiff, E.A., Wagner, S., Schropp, R. and Matsuda, A., Mat. Res. Soc. Symp. Proc., 420, 3 (1996).Google Scholar
2. Rath, J.K., Meiling, H., Schropp, R.E.I., Jpn. J. Appl. Phys., 36, 5436 (1997).Google Scholar
3. Rath, J.K., Tichelaar, F.D., Meiling, H., Schropp, R.E.I., in “Amorphous and Microcrystalline Silicon Technology-1998”, Edited by Schropp, R., Branz, H., Wagner, S., Hack, M. and Shimizu, I., Mat. Res. Soc. Symp. Proc., 507, 879 (1998).Google Scholar
4. Schropp, R.E.I., Feenstra, K.F., Molenbroek, E.C., Meiling, H., Rath, J.K., Phil. Mag. B., 76, 309 (1997).Google Scholar
5. Patel, J.R., Semiconductor Silicon 1981 (Electrochem. Soc. Pennington, 1981) p 189.Google Scholar