The behavior of powder sublimation in the long-term PVT growth of SiC crystals

The effect of different temperature distribution in powder on the powder sublimation was investigated by experiments and simulations. On the one hand, appropriately large temperature difference in the powder will contribute to high growth rate when the mass transportation between the powder and the seed proceeds smoothly. Nevertheless, the recrystallization at the bottom of powder will reduce the available powder in the growth and should be avoided. On the other hand, when the temperature difference in the powder is so large that the rate of sublimation of the powder increases beyond the normal limit of the rate of mass transportation between the powder and the seed, the mass transportation in the powder will be obstructed and even the crystal growth will be interrupted.