Simulation studies on giant step bunching in 4H-SiC epitaxial growth: Cluster effect

We have developed a computer simulation that can reproduce giant step bunching (GSB) that takes into account both the cluster effect and the Schwoebel effect. When using our simulation to investigate the conditions for generating GSB, we found that, for GSB to occur, there exists a threshold value of the surplus flux rate of Si- or C-source gases not contributing to growth, which in turn depends on the flux rate of each source gas: or, more specifically, the boundary between the presence and absence of GSB. This boundary does not depend on the off-angle of the substrate. We have also found a mechanism that explains the occurrence of wavy surface morphology.