Microscopic identification of stepped SiC(0001) and the reaction site of hydrogen-rich epitaxial growth

Abstract

We report first-principles total-energy electronic-structure calculations, based on density-functional theory, that unveil detailed atomic structures of hydrogen-adsorbed step edges and their energetics of the silicon carbide (SiC) (0001) surface. The obtained adsorption energy of the hydrogen atom at each step reveals the microscopic reason for the step morphology on the Si-face SiC(0001) surfaces which are commonly inclined toward the $\ensuremath{\langle}11\overline{2}0\ensuremath{\rangle}$ direction in epitaxial growth. The calculated hydrogen coverages at each step and also on the surface terrace clearly identify the favorable reaction sites for the epitaxial growth, such as chemical vapor deposition (CVD) in which hydrogen is ubiquitous. The obtained results provide a firm theoretical framework to discuss the atom-scale mechanism of the epitaxial growth of SiC.