Formation of clean stacking faults and oxide microdefects in Czochralski silicon

Abstract

The effect of intrinsic gettering action by microdefects in Czochralski silicon containing substantial amounts of oxygen on the properties of stacking faults (SF’s) has been studied. It has been found that high-temperature oxidation of swirl-free wafers results in the generation of SF’s decorated with probably heavy metallic impurity precipitates around the Frank partial dislocations, while high-temperature oxidation of swirled wafers results in the generation of clean SF’s. The occurrence of clean SF’s is correlated with the presence of microdefects in the bulk of wafers. Transmission electron microscopy (TEM) observations revealed that the microdefects were the precipitates (believed to be some form of silicon oxide) with generator dislocations or punched-out dislocations and that these dislocations captured impurity precipitates. These observations suggest that the microdefect dislocations are more attractive to metallic impurities in silicon than the Frank partial dislocations of the SF’s.