Structure of 3×2, 5×2, and 7×2 reconstructed 3C-SiC(001) surfaces obtained during epitaxial growth: Molecular dynamics simulations

Abstract

The stable Si-terminated 3C-SiC(001) surface exhibits a 2×1 reconstruction similar to Si(001)2×1, but with a longer dimer bond length, 2.49 vs 2.40 Å, due to a higher backbond strength. Molecular dynamics simulations show that deposition of Si adatoms on 3C-SiC(001)2×1 results in the formation of a series of missing-dimer-row type reconstructions of the type h×2 where h=...,7,5,3 with increasing ad-Si coverage. The basic building block for the h×2 surfaces is a two-ad-dimer unit. Si surface atoms below missing ad-Si dimers between neighboring ad-Si dimer pairs remain dimerized and 90° rotated. The most stable Si-terminated h×2 structure is 3C-SiC(001)3×2, which represents the closest-packed array of two-ad-dimer units, with a dangling bond density of 0.67 per 3C-SiC(001)1×1 unit cell.