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Past Work
Silicon Info


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

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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