The energy barriers to the nucleation of voids and vacancy-type dislocation loops under vacancy supersaturation conditions were calculated. The barrier for vacancy-type loops was found to be higher, than that for voids, by more than an order of magnitude. The former barrier exceeded 35eV for obtainable vacancy supersaturation levels. Therefore, voids could be nucleated but not dislocation loops. This provided an explanation for the observation that, in Si crystals which were grown under vacancy supersaturation conditions, voids existed but vacancy-type dislocation loops did not. It was also suggested that D-type swirl defects in Si were nanoscopic voids. The present calculations also predicted that the temperature range for the formation of D-type swirl defects lay below 1050C, and that the vacancy formation enthalpy was greater than about 3eV.

Nucleation Barrier of Voids and Dislocation Loops in Silicon. T.Y.Tan, P.Plekhanov, U.M.Gösele: Applied Physics Letters, 1997, 70[13], 1715-7