An investigation was made, of antisite formation, by carrying out molecular dynamics simulations; using a realistic many-atom potential. The recoil energies were chosen so as to correspond to the values which were encountered in electron irradiation experiments. It was found that the probability of forming antisites directly during cascade processes was substantial. The antisite defects were stable, and were expected to survive during long-term annealing. The results indicated that the creation of antisites was anisotropic when near to the formation threshold; which was estimated to be about 15eV. The antisites formed directly via a replacement mechanism, and no pronounced asymmetry in the relative amounts of AsGa and GaAs defects was observed. The probability of vacancy production was considerably higher than that of antisites. The focused cascades which were typical of GaAs, and resulted in a sequence of antisites, were not expected to occur in compound semiconductors (such as AlAs) with a large mass difference between the atoms on the 2 sub-lattices.

T.Mattila, R.M.Nieminen: Physical Review Letters, 1995, 74[14], 2721-4