Astropower, Inc.

Sandra R Collins

Allen M Barnett

Robert B Hall

James A Rand

David H Ford

Joseph C Checchi

Christopher L Kendall

Chad Byron Moore

Steven M Lampo

The invention relates to improved techniques for manufacturing columnar-grained polycrystalline sheets which have particular utility as substrates or wafers for solar cells. The sheet is made from silicon on a setter material which supports the silicon material. The setter material and silicon are subjected to a thermal profile all of which promote columnar growth. The thermal profile sequentially creates a melt region where a thin-film capping layer grows at the top of the silicon, a nucleation region where preferential nucleation occurs at the capping-layer/molten-silicon interface, 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 substrate and improved

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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Chesapeake City, MD, United States of America

Sandra R Collins