Characterization of defect patterns in Cz silicon slabs by carrier densityimaging

Abstract

Cu is widely used to decorate grown-in defects in Cz silicon. Instead of preferential etching, carrier density imaging is applied to characterize Cu-decorated slabs based on lifetime mapping and IR topography. The defect patterns shown by this new method are confirmed by those delineated with preferential etching, demonstrating that carrier density imaging is effective to characterize defect patterns in Cu-decorated silicon samples. Moreover, the new method is fast and etch-free, thus avoiding corrosive and toxic chemicals. The mapping results of carrier density imaging are investigated. The lifetime has a good correlation with the density of Cu precipitates, whereas the IR topography is believed to strongly depend on the stress induced by Cu precipitates.