Development and evaluation of die materials for use in the growth of silicon ribbons by the inverted ribbon growth process. Task II: LSSA project. Quarterly report No. 4

Technical Report · Fri Sep 01 04:00:00 EDT 1978

DOI:https://doi.org/10.2172/6081575· OSTI ID:6081575

Duffy, M T; Berkman, S; Moss, H I; Cullen, G W

The results of emission spectroscopic analysis indicate that molten silicon (sessile drop) can remain in contact with hot-pressed Si/sub 3/N/sub 4/ (99.2% theoretical density) for prolonged periods without attaining the impurity content level of the nitride. It is interesting to note that, although MgO was used as binder (approx. 3.8%), Mg was not found present in the silicon sessile drop in quantities much above the level initially present in the silicon source material. The conversion of CVD silicon oxynitride to ..beta..-Si/sub 3/N/sub 4/ can be carried out at high temperature in N/sub 2/ (approx. 1600/sup 0/C), by contact with molten silicon or by a combination of these steps. Conversion in the presence of molten silicon appears preferable. Preliminary experiments with EFG-type dies coated with CVD Si/sub 3/N/sub 4/ or CVD SiO/sub x/N/sub y/ indicate that capillary rise does not occur readily in these dies. The same was found to be true of hot-pressed and reaction-sintered Si/sub 3/N/sub 4/ obtained commercially. However, when dies were formed by depositing CVD layers on shaped silicon slabs, a column of molten silicon (approx. 2.5 cm high) was maintained in each CVD die while being heated (approx. 30 min) in contact with a crucible of molten silicon. Preliminary wetting of dies appears necessary for EFG growth. Several ribbon growth experiments were performed in our new ribbon growth facility from V-shaped dies. Both CVD Si/sub 3/N/sub 4/ and CVD SiO/sub x/N/sub y/ coatings were used on the die parts. There is also a problem with the wetting of SiO/sub x/N/sub y/ in the inverted ribbon growth process but not with Si/sub 3/N/sub 4/ layers. After about 90 min in contact with the melt, however, silicon flows into the defining slot in the case of SiO/sub x/N/sub y/ coatings.

• Research Organization: RCA Labs., Princeton, NJ (USA)
• Sponsoring Organization: USDOE
• DOE Contract Number: NAS-7-100-954901
• OSTI ID: 6081575
• Report Number(s): DOE/JPL/954901-4
• 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
BINDERS
CAPILLARY FLOW
COATINGS
CRUCIBLES
CRYSTAL GROWTH
DIES
ELEMENTS
FLUID FLOW
IMPURITIES
MATERIALS
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
REFRACTORIES
RESEARCH PROGRAMS
SEMIMETALS
SILICON
SILICON COMPOUNDS
SILICON NITRIDES
SUBSTRATES
VAPOR DEPOSITED COATINGS