Thermally Induced Microdefects in Czochralski-Grown Silicon: Nucleation and Growth Behavior

Abstract

The current understanding of thermally induced microdefects in Czochralski-grown silicon crystals is briefly reviewed and our investigations of the defects are described. The microdefects originate in oxygen precipitation occurring during thermal treatments after crystal growth. Both homogeneous and heterogeneous nucleation models have been proposed for the oxygen precipitation. The homogeneous nucleation model is contradicted because a low density of microdefects are induced in recent high-quality crystals even at high oxygen concentrations. A heterogeneous nucleation model is proposed, based on detailed investigations of the thermal behaviors of microdefects. It is demonstrated that the oxygen precipitation is governed by nucleation sites (carbon atoms) and the thermal history of wafers after crystal growth besides the oxygen concentration of the wafer.