Macroscopic modelling of silicon carbide sublimation: toward a microscopic modelling of defect formation

Abstract

The deposition of single SiC crystals has been processed inside a sealed enclosure at temperatures above 2300 K and pressures lower than 5 × 10 3 Pa by the modified Lely method. The purpose of this work is to present different optimized macroscopic models, thermodynamics, heat and mass transfers used in the simulation of the growth of such crystals. Thermodynamic modelling has been used to determine the most important reactive species involved in equilibrium conditions. Induction heating modelling has allowed the calculation of the actual temperatures inside the reactor which are not well known because of the difficulty associated with their measurement. Finally, mass transport modelling provided the calculated deposition rate. It was found that the calculated growth rates were close to the experimental ones which may indicate a good representation of the actual phenomena involved in the crucible. Moreover, defect formation, which is the primary obstacle to the production of large area devices, is explained by local sublimation of the growing ingot and related to the temperature gradients existing within the crystal and graphite holder.