High-frequency furnace. Eleventh quarterly report for period ending June 30, 1984
An important phase of silicon solar cell production via ingot technology is the conversion of polycrystalline silicon to the single-crystal, ingot form that is required for wafering. In the current art such ingots are produced either by pulling from the melt or by various crucible growth techniques. A characteristic of all of these methods, which use bulk melting, is that a refractory crucible is required to hold the molten charge. This imposes the disadvantages that the silicon is always contaminated to some degree by dissolution of the refractory into the melt, which can reduce solar cell efficiency, and the crucibles themselves represent a significant cost factor. Clearly, elimination of the need for a refractory crucible in the melt growth of single-crystal silicon would be an important process improvement. Work to be conducted under the present Grant Award is to investigate a radical, new heating technique which holds potential for achieving crucibleless melting. Ingots would be pulled from the melt as per conventional practice. Briefly, a high frequency current (10 KHz) is caused to flow on the surface of a mass of metal as a result of skin effect and proximity effect. By controlling the power input and heat losses from the billet it is anticipated that it will be possible to form and maintain in its top surface a molten pool which will be contained in a solid, outer layer or skull of metal. The basic objectives of the project are to prove the general feasibility of this melting technique. This is to be accomplished by building and operating a small, experimental furnace. To simplify the project as much as possible and to minimize research costs, cast iron will be used in place of silicon for melt experiments.
- Research Organization:
- Zumbrunnen (Allen D.), Salt Lake City, UT (USA)
- DOE Contract Number:
- FG01-81CS15077
- OSTI ID:
- 6798408
- Report Number(s):
- DOE/CS/15077-T10; ON: DE84014179
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
ELECTRIC FURNACES
POWER SYSTEMS
SILICON
MELTING
COOLING SYSTEMS
FORCED CONVECTION
CONVECTION
ELEMENTS
ENERGY SYSTEMS
FURNACES
PHASE TRANSFORMATIONS
SEMIMETALS
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture