Patent ID: 9738991
Date: 2017-08-22
CPC Classifications: C23C,C30B,Y10T

Claim:
1. A method of forming an SiC crystal using a seed crystal having a given diameter, the method comprising: a. providing a graphite container having an interior diameter which is larger than the diameter of the seed crystal and having a shelf on an interior sidewall of the graphite container with an inner diameter which is smaller than the diameter of the seed crystal; b. placing a source of silicon and carbon atoms in the insulated graphite container, wherein the source of silicon and carbon atoms is for transport to the seed crystal to grow the SiC crystal; c. placing the seed crystal on the shelf and placing a lid on the graphite container to form a ceiling while preventing an exposed back surface of the seed from contacting the ceiling, thereby defining a volume between ceiling of the graphite container and the exposed back surface of the seed; d. providing means for directing gas flow from a periphery of the seed crystal to the volume; e. placing the graphite container inside a furnace; f. evacuating the furnace and filling with inert gas to a pressure above 600 torr; g. heating the furnace to a temperature from about 2,000° C. to about 2,500° C.; and, h. evacuating the induction furnace to a pressure of from about 0.1 Torr to about 100 Torr, while directing gas flow from below the seed crystal through a periphery of the seed crystal and to a center of the volume between ceiling of the graphite container and the back surface of the seed, to thereby facilitate vapor transport from the source of silicon and carbon atoms to the seed while preventing the back surface of the seed from contacting the ceiling.