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Past
Work: Edge-Supported Pulling of Si Ribbons ("String Ribbon")
| In
1979, we were looking for a rugged growth method for Si sheets,
with minimal susceptibility to disruption from thermal perturbations. The method we devised was Edge-Supported Pulling, or ESP, in which the
edges of the meniscus from which the ribbon solidified were stabilized
or supported by two foreign filaments on each edge of the
ribbon. Ribbons 50 mm wide were grown
and reported in 19801.
The system is tolerant of ± 5oC
temperature variations. Cell efficiencies as high as 13.8% (93% of co-processed CZ value) were
obtained. We patented the method 2,3 and conducted
further work to explore filament materials4. The
technology was licensed to Arthur D. Little Corporation and then later
transferred to Evergreen Solar, where it was commercialized as
"String Ribbon." |
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Schematic of Growth
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 A Growing 50-mm Ribbon
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1. T.F.
Ciszek and J.L. Hurd, "Melt Growth of Silicon Sheets by Edge-Supported Pulling,"
in: Proceedings of the Symposia on Electronic and Optical Properties of Polycrystalline or
Impure Semiconductors and Novel Silicon Growth Methods, Ed. K.V. Ravi and B.
O'Mara. St.
Louis, MO; ll-l6 May, l980, the Electrochemical Soc., Pennington, NJ, 1980, Proceedings
Volume 80-5, pp. 2l3-222.
2. Theodore
F. Ciszek, "Method and Apparatus for Forming Silicon Crystalline
Bodies," U.S. Patent 4,239,734 (1980).
3. Theodore F. Ciszek, "Method For
Forming Silicon Crystalline Bodies," U.S. Patent 4,304,623 (1981).
4. T.F. Ciszek, J.L. Hurd,
and M. Schietzelt, "Filament Materials for Edge‑Supported Pulling of
Silicon Sheet Crystals," J. Electrochem. Soc. 129 (1982) 2838.
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