Microscopic Identification of Surface Steps on SiC by Density-Functional Calculations

Abstract

We have performed density-functional calculations in order to clarify atomic structures and energetics of surface steps on SiC. The obtained energetics of distinct step types on vicinal 3C-SiC(111) surfaces which correspond to 4H- and 6H-SiC(0001) surfaces reveals the atom-scale reason for the experimental observation in the past that the step morphology is straight for the SiC(0001) surfaces inclined toward the 〈1-100〉 direction while it is meandering for the 〈11-20〉 inclined surfaces. The calculations clarify the rebonding between upper- and lower-terrace edge atoms, which is decisive for the energetics of the atomic steps.