Nucleation barrier of voids and dislocation loops in silicon

Abstract

We have calculated the nucleation energy barrier of voids and vacancy (V) type dislocation loops in Si under V-supersaturation conditions. The barrier of V-type dislocation loops is higher than that of voids by more than one order of magnitude, with the former exceeding 35 eV at attainable V-supersaturation levels. Thus, voids can be nucleated, but not dislocation loops. This provides an explanation for the observations that, in Si crystals grown under V-supersaturation conditions, voids exist but V-type dislocation loops do not. Voids seriously degrade the Si device gate oxide integrity. It is highly probable that the D-type swirl defects in Si are nanoscopic voids. Our calculated results have also provided information for limiting the formation temperature range of the D-swirl defects to be lower than ∼1050 °C, and the Si V formation enthalpy to be above ∼3.0 eV.