Nature and Shape of Stacking Faults in 3C-SiC by Molecular Dynamics Simulations

Classical molecular dynamics simulations are used to investigate the 3D evolution of stacking faults (SFs), including the partial dislocation (PD) loops enclosing them, during growth of 3C-SiC layers on Si(001). It is shown that the evolution of single PD loops releasing tensile strain during the initial carbonization stage, commonly preceding 3C-SiC deposition, leads to the formation of experimentally observed V- or Δ-shaped SFs, the key role being played by the differences in the mobilities between Si- and C-terminated PD segments. Nucleation in the adjacent planes of PD loops takes place at later stage of 3C-SiC deposition, when slightly compressive-strain conditions are present. It is shown that such a process very efficiently decreases the elastic energy of the 3C-SiC crystal. The maximum energy decrease is obtained via the formation of triple SFs with common boundaries made up by PD loops yielding a zero total Burgers vector. Obtained results explain the experimentally observed relative abundance of compact microtwin regions in 3C-SiC layers as compared with the other SF-related defects.