Effect of graphitization degree of crucible on SiC single crystal growth process

Effects of graphite crucible on the mass transport and the growth rate of the SiC single crystal in fabricating SiC single crystal has been investigated by the seeded sublimation growth method. Different graphitization degrees of the crucibles were obtained by heat treatment at various temperatures between 2100 degrees C and 2300 degrees C. The crucibles were subjected to SEM observation, XRD investigation, and the graphitization degree was determined quantitatively. The experimental results indicate that the graphite crucible is an important C source provider in the SiC crystal growth. High crystal growth rate is obtained by using the untreated crucibles (corresponding to low graphitization degree), which contributed to the reaction activity between Si and graphite of the crucible. Increasing the graphitization degree resulted in degradation in crystal growth, even graphitization of the SiC seed crystal.