Heat exchanger method, ingot casting; fixed abrasive method, multi-wire slicing: Phase II. Silicon sheet growth development for the Large-Area Silicon Sheet Task of the Low-Cost Silicon Solar Array Project. Quarterly progress report No. 2, January 1, 1978--March 31, 1978
A crack-free silicon ingot has been cast in a graded, semiconductor purity silica crucible. More than 90% single crystallinity has been achieved in 2.5 kg cast ingots. The impurities on the surface of the melt have been reduced with the use of a rapid heat-up cycle and absence of graphite retainers. Solar cells fabricated out of HEM cast material have shown conversion efficiency up to 14% under AM1 Xenon source illumination. Considerable progress has been achieved in casting square cross-section ingots. The growth in the corners has been obtained but the problem area is in fabricating a custom-made graded crucible. Kerf loss was reduced to 6.2 mil, 0.155 mm in slicing 4 cm x 4 cm cross-section with 100% yield. The abrasive life of plated impregnated blades was increased by hardening the electroless nickel layer. In an effort to prevent diamond pull-out and thereby improve the abrasive life, the plated layer was increased from 0.3 mil, 7.5 ..mu..m to 0.5 mil, 12.5 ..mu..m. The extra thickness buried the diamonds. A thinner copper sheath for impregnation and a thicker nickel coating to prevent diamond pull-out is expected to improve the abrasive life. Higher feed forces increased the cutting rates but resulted in deeper surface damage.
- Research Organization:
- Crystal Systems, Inc., Salem, Mass. (USA)
- DOE Contract Number:
- NAS-7-100-954373
- OSTI ID:
- 6772814
- Report Number(s):
- DOE/JPL/954373-6
- Country of Publication:
- United States
- Language:
- English
Similar Records
Silicon ingot casting: heat exchanger method multi-wire slicing, fixed abrasive slicing technique. Phase IV. Silicon sheet growth development for the large area sheet task of the Low-Cost Solar Array Project. Quarterly progress report No. l, December 15, 1979-March 31, 1980
Heat exchanger method - ingot casting fixed abrasive method - multi-wire slicing. Phase II. Silicon sheet growth development for the Large Area Sheet Task of the Low Cost Solar Array Project. Quarterly progress report No. 4 for July 1--September 30, 1978
Related Subjects
36 MATERIALS SCIENCE
SILICON
CASTING
CUTTING
ABRASIVES
CRUCIBLES
CRYSTAL STRUCTURE
EFFICIENCY
HEAT EXCHANGERS
IMPURITIES
MONOCRYSTALS
SILICON SOLAR CELLS
CRYSTALS
DIRECT ENERGY CONVERTERS
ELEMENTS
FABRICATION
MACHINING
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SEMIMETALS
SOLAR CELLS
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture