Single-crystal – oriented-crystal – and epitaxy growth processes; – Forming from vapor or gaseous state – Fully-sealed or vacuum-maintained chamber
Reexamination Certificate
2006-12-12
2006-12-12
Hiteshew, Felisa (Department: 1722)
Single-crystal, oriented-crystal, and epitaxy growth processes;
Forming from vapor or gaseous state
Fully-sealed or vacuum-maintained chamber
C117S089000, C117S093000, C117S105000
Reexamination Certificate
active
07147715
ABSTRACT:
A method is disclosed for producing semi-insulating silicon carbide crystal with a controlled nitrogen content. The method includes the steps of introducing an ambient gas containing hydrogen into a sublimation growth chamber, heating a silicon carbide source powder to sublimation in the hydrogen ambient growth chamber while, heating and then maintaining a silicon carbide seed crystal in the hydrogen ambient growth chamber to a second temperature below the temperature of the source powder, at which second temperature sublimed species from the source powder will condense upon the seed crystal, continuing to heat the silicon carbide source powder until a desired amount of silicon carbide crystal growth has occurred upon the seed crystal, while maintaining an ambient concentration of hydrogen in the growth chamber sufficient to minimize the amount of nitrogen incorporated into the growing silicon carbide crystal, and while maintaining the source powder and the seed crystal during sublimation growth at respective temperatures high enough to increase the number of point defects in the growing crystal to an amount that renders the resulting silicon carbide crystal semi-insulating.
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Hobgood Hudson McDonald
Jenny Jason Ronald
Malta David Phillip
Tsvetkov Valeri F.
Cree Inc.
Hiteshew Felisa
Summa, Allan & Addition, P.A.
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