Silicon sheet growth by the inverted Stepanov technique. Quarterly report No. 4

Technical Report · Tue Mar 01 04:00:00 EST 1977

DOI:https://doi.org/10.2172/7305309· OSTI ID:7305309

Berkman, S.; Cullen, G. W.; Duffy, M. T.; Kim, K. M.

Chemically vapor deposited silicon nitride and silicon oxynitride (CVD-Si/sub 3/N/sub 4/ and CVD-SiO/sub x/N/sub y/, respectively) are being evaluated as the contact material for molten silicon in the ribbon growth configuration. Thin films of the contact material are deposited on substrates such as boron nitride (BN) and hot-pressed and reaction-sintered silicon nitride (RS-Si/sub 3/N/sub 4/). Preliminary evaluation of the reactivity of molten silicon with the CVD-Si/sub 3/N/sub 4/ and CVD-SiO/sub x/N/sub y/ indicates that these materials are considerably more resistant to reaction with and/or dissolution in silicon than other materials examined to date. The SiO/sub x/N/sub y/ appears to be more stable in contact with the molten silicon than the Si/sub 3/N/sub 4/. Of the various substrates examined, RS-Si/sub 3/N/sub 4/ is the most favored. There is a problem, however, in obtaining high-purity, reaction-sintered Si/sub 3/N/sub 4/. Reaction-sintered Si/sub 3/N/sub 4/ and BN die materials used for the growth of silicon ribbon were coated with CVD-Si/sub 3/N/sub 4/. Various graphite substrates were coated with CVD-Si/sub 3/N/sub 4/ and CVD-SiO/sub x/N/sub y/ and used in silicon sessile drop experiments to determine compatibility in thermal expansion properties between film and substrate. Among six graphite grades (from Ultra Carbon Corporation), substrates designated UT-8 were most compatible with both types of CVD coatings in the sessile drop tests. Ribbon growth runs have been carried out using dies coated with the CVD-Si/sub 3/N/sub 4/. Stable growth of narrow ribbons has been achieved. The grown ribbons are typically 0.05 to 0.06 cm thick, 0.3 to 0.5 cm wide.

• Research Organization: RCA Labs., Princeton, NJ (USA)
• DOE Contract Number: NAS-7-100-954465
• OSTI ID: 7305309
• Report Number(s): ERDA/JPL/954465-77/1; PRRL-77-CR-12
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
BORON COMPOUNDS
BORON NITRIDES
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
CRYSTAL GROWTH
DEPOSITION
DIRECT ENERGY CONVERTERS
ELEMENTS
NITRIDES
NITROGEN COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PNICTIDES
PURIFICATION
SEMIMETALS
SILICON
SILICON COMPOUNDS
SILICON NITRIDES
SILICON SOLAR CELLS
SOLAR CELLS
SUBSTRATES
SURFACE COATING