Influence of seed and crucible rotation on surface morphology during solution growth of 6-inch 4° off-axis SiC

The off-axis growth of SiC on C-face is strongly governed by seed or crucible rotation modes, exhibiting a specific surface step pattern. For unidirectional seed rotation, a macroscopic vortex-like pattern is observed across the entire crystal surface, corresponding to the flow field beneath the seed crystal. This results in macrosteps with heights reaching several millimeters. To suppress such surface roughening, the accelerated crucible rotation technique was applied to generate alternating azimuthal flow, producing antiparallel and parallel step-flow regions. However, this leads to anisotropy of the steps, with an increase in average step height from 5 µm to 170 µm along the[11–20] direction. To further reduce this step height discrepancy, switching rotation of both the seed and crucible was implemented, inducing alternating radial and azimuthal flows. This approach effectively decreases the average step height to approximately 30 µm.