Solar silicon via improved and expanded metallurgical silicon technology. Quarterly report No. 4

Technical Report · Fri Jul 01 00:00:00 EDT 1977

DOI:https://doi.org/10.2172/7293316· OSTI ID:7293316

Hunt, L. P.; Dosaj, V. D.; McCormick, J. R.

The goal of this program is to produce solar-cell-grade silicon at 3000 Mt/y for less than $10/kg by 1986. The approach is to improve the quality of the 200,000-Mt/y process for producing $1/kg, 98-percent pure metallurgical silicon. A completed preliminary survey of silica sources indicates that sufficient quantities of high-purity quartz are available in the U.S. and Canada to meet LSSA goals. Supply can easily meet demand for this little-sought commodity. Charcoal, as a reductant for silica, can be purified to a sufficient level by high-temperature fluorocarbon treatment and vacuum processing. High-temperature treatment causes partial graphitization which can lead to difficulty in smelting. Smelting of Arkansas quartz and purified charcoal produced kilogram quantities of silicon having impurity levels generally much lower than in MG-Si. Half of the goal was met of increasing the boron resistivity from 0.03 ohm-cm in metallurgical silicon to 0.3 ohm-cm in solar silicon. A cost analysis of the solidification process indicates $3.50-7.25/kg Si for the Czochralski-type process and $1.50 to 4.25/kg Si for the Bridgman-type technique.

• Research Organization: Dow Corning Corp., Hemlock, Mich. (USA). Solid-State Research and Development Lab.
• DOE Contract Number: NAS-7-100-954559
• OSTI ID: 7293316
• Report Number(s): ERDA/JPL/954559-77/2
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
SILICON
PRODUCTION
ARC FURNACES
CHARCOAL
COST
PURIFICATION
QUARTZ
RESEARCH PROGRAMS
SILICA
SILICON SOLAR CELLS
SMELTING
ADSORBENTS
CHALCOGENIDES
DIRECT ENERGY CONVERTERS
ELEMENTS
FURNACES
MINERALS
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SEMIMETALS
SILICON COMPOUNDS
SILICON OXIDES
SOLAR CELLS
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture