The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 10, 1999
Filed:
May. 08, 1997
Donovan L Barrett, Port Orange, FL (US);
Richard H Hopkins, Export, PA (US);
James P McHugh, Pittsburgh, PA (US);
Hudson McDonald Hobgood, Murrysville, PA (US);
Northrop Grumman Corporation, Los Angeles, CA (US);
Abstract
A nitrogen doped single crystal silicon carbide boule is grown by the physical vapor transport process by introducing nitrogen gas into the growth furnace. During the growth process the pressure within the furnace is maintained at a constant value, P.sub.o, where P.sub.o .ltoreq.100 Torr. This is accomplished by measuring the pressure within the furnace and providing the pressure measurement to a process controller which regulates the nitrogen introduction as nitrogen gas is incorporated into the crystal structure. The partial pressure of the nitrogen may be selected to be at a value between 1 and P.sub.o. If the desired partial pressure is less than P.sub.o, an inert gas is added to make up the difference.