Accession Number:

AD0276160

Title:

BETA-SILICON CARBIDE AND ITS POTENTIAL FOR DEVICES

Descriptive Note:

Corporate Author:

STANFORD RESEARCH INST MENLO PARK CALIF

Personal Author(s):

Report Date:

1962-05-15

Pagination or Media Count:

1.0

Abstract:

Initial measurements of the N content of SiC crystals, grown by the solution technique during the previous program, showed a level of 7.3 x 10 to the 18th power atomscc. This is closely comparable to the value 2.1 x 10 to the 19th power carrierscc obtained previously from Hall measurements on these crystals. Although additional measurements will be required to assure the validity of these results, these data appear to confirm that N is the impurity doping these crystals. In considering the sources for N contamination during crystal growth, it appears that N adsorbed on the graphite crucible and subsequently incorporated into the SiC coating is responsible. In view of the gettering action of crystallizing SiC at low temperatures and the fact that the SiC coating acts as the sources of C during crystal growth, it is considered that improvements in the coating technique are essential. For this reason, a Si vapor deposition process was selected to replace the powder application procedure previously employed. With this new process, the crucible can be vacuum-outgassed at a high temperature and repeatedly coated and reacted to form the SiC layer without exposing the crucible to air at any point in the coating process. Pyrolytic graphite is also being evaluated as a high-purity crucible material. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE