Accession Number : AD0739183

Title :   On the Formation of Beta-SiC in the Initial Growth Stage,

Corporate Author : EMMANUEL COLL BOSTON MASS ORIENTAL SCIENCE RESEARCH LIBRARY

Personal Author(s) : Inomata,Y. ; Matsumoto ,S.

Report Date : 07 JAN 1972

Pagination or Media Count : 22

Abstract : The formation of Beta-SiC at temperatures outside its thermally stable range of 1,400-1,600C was studied experimentally using the sublimation procedure and the synthetic method with molten silicon. From consideration of the molar surface energy of Beta- and alpha-SiC, the following are shown to be the main causes for the phenomenon: (1) Given an equal volume of crystallites, the molar surface energy of the Beta-type is always lower than that of the alpha-type based on its higher lattice symmetry; (2) the bonding energy of the Beta-type is the lowest among the SiC polytypes from comparison of the band gaps; (3) the rate of transition from the Beta- to the alpha-type is not too large. The free energy gaps among the SiC polytypes were found to be smaller than 100 cal/mole. The effects of pressure and polarity are also discussed. (Author)

Descriptors :   (*SILICON CARBIDES, *CRYSTAL GROWTH), PHASE STUDIES, CRYSTAL STRUCTURE, JAPAN

Subject Categories : Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE