SiC single crystal sublimation growth method and apparatus

A SiC single crystal sublimation growth method comprising:

• (a) providing a growth chamber that is separated by a porous graphite membrane into a source compartment that is charged with a SiC source material and a crystallization compartment that includes a SiC seed crystal;
• and
• (b) heating the interior of the growth chamber such that a temperature gradient forms between the SiC source material and the SiC seed crystal, the SiC source material is heated to a sublimation temperature, and the temperature gradient is sufficient to cause sublimated SiC source material to diffuse through the porous graphite membrane from the source compartment into the crystallization compartment where the sublimated SiC source material condenses on the SiC seed crystal and forms the SiC single crystal, wherein all of the sublimated SiC source material that condenses on the SiC seed crystal and forms the SiC single crystal diffuses through the porous graphite membrane from the source compartment into the crystallization compartment, wherein the porous graphite membrane is comprised of carbon that is reactive to silicon-rich vapor generated by precipitation of the sublimated SiC source material on the SiC seed crystal in the crystallization compartment, wherein the porous graphite membrane is positioned in the growth chamber such that the generated silicon-rich vapor diffuses in a direction from a growth interface of the SiC single crystal on the SiC seed crystal toward the porous graphite membrane, in spite of Stefan gas flow in an opposite direction, where the silicon-rich vapor reaches the porous graphite membrane and reacts with the carbon comprising the porous graphite membrane to produce a carbon-bearing vapor that acts as an additional source of C during the growth of the SiC single crystal on the SiC seed crystal, wherein:
• a distance between the growing SiC single crystal and the porous graphite membrane is between 15 mm and 35 mm;
• the temperature of the SiC source material is greater than the temperature of the porous graphite membrane;
• the temperature of the porous graphite membrane is greater than the temperature of the SiC seed crystal;
• and
• the porous graphite membrane is comprised of porous graphite grains, each having a maximum dimension between 100 micron and 500 micron.