Development and evaluation of die and container materials. Third quarterly progress report, April 1--June 30, 1978. [For molten silicon]

Technical Report · Sat Jul 15 04:00:00 EDT 1978

DOI:https://doi.org/10.2172/6617945· OSTI ID:6617945

Wills, R R; Niesz, D E

Methods of producing low-cost silicon sheet for solar cells are under active development. In the crystal-growing processes a refractory crucible is required to hold the molten silicon, while in the ribbon processes an additional refractory shaping die is needed to enable silicon ribbon to be produced. In several ribbon processes the high-temperature materials are a limiting factor in the development of the technique. The objective of this study is to develop and evaluate refractory die and container materials. Mass spectrometric studies of molten silicon in contact with silicon nitride and silicon carbide show that the vapor pressure of silicon is lower over these materials than over the oxides (beryllium oxide, alumina, and silica) studied previously. Measured carbon and nitrogen contents are 6.4 x 10/sup 19/ atoms/cm/sup 3/ and 3.3 x 10/sup 18/ atoms/cm/sup 3/, respectively. The fabrication of O' and ..beta..' Sialons was found to be strongly dependent upon the nature of the silicon nitride powder. A modified hot pressing procedure was adopted to allow volatilization of chlorine-containing species from the SN402 grade powder. ..beta..' Sialon of composition X = 1 appears to offer some promise as a candidate die material, but materials containing a higher alumina composition (X = 2.4 Sialon) or the phase known as X phase with molten silicon. O' Sialons of compositions X = 0.1, X = 0.2, and X = 0.35 reacted with molten silicon, forming a complex interface zone. The concentration of thin precipitates in the silicon increased with the alumina content of the O' Sialon solid solution.

• Research Organization: Battelle Columbus Labs., OH (USA)
• DOE Contract Number: NAS-7-100-954876
• OSTI ID: 6617945
• Report Number(s): DOE/JPL/954876-78/3
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
36 MATERIALS SCIENCE
360601 -- Other Materials-- Preparation & Manufacture
ALUMINIUM COMPOUNDS
ALUMINIUM NITRIDES
ALUMINIUM OXIDES
CASTING
CHALCOGENIDES
COMPATIBILITY
CONTAINERS
CRUCIBLES
DIES
DIRECT ENERGY CONVERTERS
ELEMENTS
FABRICATION
HOT PRESSING
MASS SPECTROSCOPY
MATERIALS
MATERIALS WORKING
NITRIDES
NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
PNICTIDES
POWDERS
PRESSING
PRODUCTION
REFRACTORIES
SEMIMETALS
SILICON
SILICON COMPOUNDS
SILICON NITRIDES
SILICON SOLAR CELLS
SOLAR CELLS
SPECTROSCOPY
THERMODYNAMIC PROPERTIES
VAPOR PRESSURE