A study was made of defect formation and defect distributions under low-energy (25 to 800eV) self-bombardment of the (2 x 1)-terminated (001) surface. Classical molecular dynamics techniques were used to detect defect production trends in the energy dependence. The number of defects which was created during implantation was found to be a super-linear function of energy at energies below 400eV. It was found that the surface strongly affected both the threshold displacement energy and the damage creation mechanism. At energies between 10 and 15eV, a very close vacancy-interstitial pair could be formed in the bulk and, above 15.5eV, a replacement process took. Because of reconstruction, the threshold energy for close-pair formation at the surface was higher (above 13eV). As in the bulk, replacement-like processes began to occur around 15.5eV. The depth distribution of defects was found to be significantly greater than the ion penetration depth.

Effect of surface on defect creation by self-ion bombardment of Si(001) J.Tarus, K.Nordlund, A.Kuronen, J.Keinonen: Physical Review B, 1998, 58[15], 9907-15