Investigation of the Growth Kinetics of SiC Crystals during Physical Vapor Transport Growth by the Application of In Situ 3D Computed Tomography Visualization

Computed tomography using X‐rays is applied during the bulk growth of silicon carbide (SiC) to investigate growth kinetics in situ during the physical vapor transport process. In addition to the standard SiC source material, in particular, a pure solid source SiC block is used. It is found that the growth rate is lowered as the sublimation of gaseous species is limited to the top part of the solid source. The morphological changes in the source area during growth differ significantly compared with the process when conventional powder is used. The formation of multiple growth centers on the surface of the seed is monitored in situ with a computed tomography system. In a series of experiments, the influence of the supersaturation on the growth is examined. The in situ computed tomography shows that the curvature of the growth interface is stronger influenced by the thermal field at higher pressures. A high supersaturation leads to the formation of rather smooth surface morphologies, whereas the formation of large steps on the surface is induced at lower supersaturations. Herein, the influence of the supersaturation on the morphology of SiC bulk crystals is evaluated. A low concentration of reactive species on the seed leads to the occurrence of several growth centers located next to each other at the beginning of the growth process. The formation and growth are observed during the experiment with a computed tomography (CT) system.