Todd R Ruffins

US Patent:

53363353, Aug 9, 1994

Filed:

Oct 9, 1992

Appl. No.:

7/959009

Inventors:

Robert B. Hall - Newark DE
Allen M. Barnett - Newark DE
Jacob E. Brown - Newark DE
Joseph C. Checchi - Newark DE
David H. Ford - Wilmington DE
Christopher L. Kendall - Wilmington DE
William P. Mulligan - Hockessin DE
James A. Rand - Oxford PA
Todd R. Ruffins - Newark DE

Assignee:

AstroPower, Inc. - Newark DE

International Classification:

H01L 310392
H01L 310368
H01L 3118

US Classification:

136258

Abstract:

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.