Radio frequency induction heating in the crucible wall permits improved thermal control of the melt solid interface shape in Bridgman-Stockbarger crystal growth. The crucible must: be refractory to withstand the semiconductor melt temperatures, have material strength to withstand the internal vapor pressure of the melt constituents, be electrically conducting to serve as a rf susceptor, be chemically inert to materials being grown, and be sealed because the volatility of the constituents, The only likely crucible material is glassy polymeric carbon (GPC), studied since the 1960's.
Physical, mechanical, and electrical characterization of GPC were needed as a function of heat treatment temperature (HTT) for theoretical modeling and furnace design. Physical, mechanical, and electrical properties have been compared to other research. Various GPC treatments used HTT from 1270 to 2770 K. Sample dimensions and mass loss measurements were made to determine GPC shrinkage due to high temperature heat treatment. XRD was performed to compare this sample with past measurements performed by Jenkins. Hoop strength, strain, and Young modulus were measured using a calibrated high pressure stress analysis system designed to isolate the pure hoop stress component. A Kelvin double bridge circuit was constructed to determine GPC resistivity. We control the electrical resistivity and mechanical properites of GPC by selecting the proper HTT.
R.J. Naumann and S.L. Lehoczky, J. Cryst. Growth, 61 (1983) 707. T. Jasinski and A.F. Witt, J. Cryst. Growth, 71 (1985) 295. L. R. Holland, J. Cryst. Growth, 96, (1989) 577. J.H. Fisher, G.Shelby, and L.R. Holland, NASA Conference Publication 3259, 247-252. L.R. Holland, J. Cryst. Growth 66, (1984) 501. G.M. Jenkins and K. Kawamura, Polymeric Carbons-Carbon Fibre, Glass, and Char, Cambridge University Press (London, 1976). H.K. Jena, PhD. Dissertation Alabama A&M University Department of Physics, July 1994.J. H. Fisher, L.R. Holland, G.M. Jenkins, and H. Maleki, 22nd International Carbon Conference, July 95, San Diego, CA. Submitted for review to Carbon.
NGG-40010 Dr. Alex Lehoczky, the NASA Space Grant Fellowship sponsor NSF/MRCE NSF-HRB 9353548 Dr. Alton Williams, NSF/MRCE principle investigator Nichols Research Corporation. Georgia Pacific for assistance in selecting the lamenating resin and suppling our research team with ample stock.
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