Kinetic Monte Carlo study on the island shape evolution of the SiC crystal during the sub-monolayer nucleation growth

SiC crystal is a key material in the improvement of the efficiency of power and electronic devices. A controllable growth of SiC crystal epitaxial layer with lower defect density and higher efficiency is still a common goal for the industries. In this paper, an improved kinetic Monte Carlo algorithm is established to investigate the effect of temperature and partial flux on the shape evolution of SiC (0001) islands. The simulation morphologies are consistent with the previous experimental observation that the clusters with triangular shape are grown at lower temperature and regular hexagonal SiC domains are obtained at higher temperature. In addition, at lower temperature, triangles with opposite directions are formed, and a reversible shape transformation occurs due to the competition between kinetic and thermodynamic effect. In contrast, the shape of island tends to evolve to the most stable one at higher temperature. For the cases under different partial flux, the triangular flakes with opposite orientations are obtained. Finally, we speculate that the coexistence of triangular islands with opposite direction might be achieved under a comparable kinetic and thermodynamic effect or a local misbalance of constituent elements circumference.