CARRIER LIFETIME AND X-RAY-IMAGING CORRELATIONS OF AN OXIDE-INDUCED STACKING-FAULT RING AND ITS GETTERING BEHAVIOR IN CZOCHRALSKI SILICON

The characterization of a unique crystal originated and thermally acti vated defect zone in Si wafers called an oxide-induced stacking fault (OSF) ring has been carried out using two noncontacting techniques. Th e minority-carrier lifetime has been mapped using the laser microwave photoconductance decay (LM-PCD) method and correlated with a transmiss ion x-ray topographic image of the wafer. Additional details of the la teral and depth dependent stacking fault density were revealed by pref erential etching. The minority-carrier lifetime within the annular OSF ring itself was about one order of magnitude lower than that outside the ring, while intermediate lifetime values were observed inside the ring. Temperature-dependent LM-PCD measurements revealed that a redist ribution of the metallic impurity Fe occurred via gettering by the sta cking faults. These findings were confirmed and quantified by deep-lev el transient spectroscopy. Implications for radial variations in devic e yield are discussed in the context of the depth distribution of the extended defects, their impurity gettering action, and wafer-to-wafer variations in the nature of the OSF ring. (C) 1996 American Institute of Physics.