Columnar-grained polycrystalline solar cell and process of manufacture

US5336335A · kind A · utility

Assignee

• ASTROPOWER, INC. · US

Inventors

• Robert B. Hall · Newark, US
• Allen M. Barnett · Landenberg, US
• Jacob Embree Brown · Newark, US
• Joseph C. Checchi · Newark, US
• David H. Ford · Wilmington, US
• Christopher L. Kendall · Wilmington, US
• William P. Mulligan · San Jose, US
• James A. Rand · New Garden Township, US
• Todd R. Ruffins · Newark, US

Key dates

• Filing date: Oct 9, 1992
• Grant date: Aug 9, 1994
• Expiry date: Oct 9, 2012

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/12528

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.