Structure of 3x2, 5x2, and 7x2 reconstructed 3C-SiC(001) surfaces obtained during epitaxial growth: Molecular dynamics simulations

The stable Si-terminated 3C-SiC(001) surface exhibits a 2X1 reconstruction similar to Si(001)2X1, but with a longer dimer bond length, 2.49 vs 2.40 Angstrom, due to a higher backbond strength. Molecular dynamics simulations show that deposition of Si adatoms on 3C-SiC(001)2X1 results in the formation of a series of missing-dimer-row type reconstructions of the type hX2 where h=...,7,5,3 with increasing ad-Si coverage. The basic building block for the hX2 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 degrees rotated. The most stable Si-terminated hX2 structure is 3C-SiC(001)3X2, which represents the closest-packed array of two-ad-dimer units, with a dangling bond density of 0.67 per 3C-SiC(001)1X1 unit cell. (C) 1996 American Institute of Physics.