Morphology of as-implanted damage in silicon: a molecular dynamics study

The authors have analyzed the damage produced by 5 keV Si cascades in Si using molecular dynamics simulations. In order to make a statistical study of the features of the damage 283 independent cascades have been simulated. Relations between the number of displaced atoms and the size and morphology of produced damage have been studied. Using a criteria for identifying defects that eliminates thermal noise in atom positions, the distribution of the displaced atoms in the cascades were obtained. The mean number of displaced atoms per cascade is 346. About 50 % of the cascades generate between 300 and 400 displaced atoms, although significant deviations from the average values are found. The analysis of the ´deviated cascades´ has revealed an interesting relation between the number of displaced atoms of the cascade and the size of the defects that it has produced. The correlations between the results and those predicted by the modified Kinchin-Pease formula are also discussed.