Astropower, Inc.

Todd R Ruffins

Allen M Barnett

Robert B Hall

James A Rand

David H Ford

Joseph C Checchi

Christopher L Kendall

William P Mulligan

Jacob E Brown

The invention relates to techniques for manufacturing columnar-grained polycrystalline sheets which have particular utility as substrates or wafers for solar cells. The sheet is made by applying granular silicon to a setter material which supports the granular material. The setter material and granular silicon are subjected to a thermal profile all of which promote columnar growth by melting the silicon from the top downwardly. The thermal profile sequentially creates a melt region at the top of the granular silicon and then a growth region where both liquid and a growing polycrystalline sheet layer coexist. An annealing region is created where the temperature of the grown polycrystalline silicon sheet layer is controllably reduced to effect stress relief.

Columnar-grained polycrystalline solar cell and process of manufacture

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Newark, DE, United States of America

Todd R Ruffins