Swirl defects in dislocation-free Czochralski-type crystals were investigated by using preferential etching, transmission electron microscopy and electron energy loss spectroscopy. Two types of swirl defect were found, with a clear correspondence between a striated pattern consisting of hillocks and buried micro-defects. The Swirl defects were identified as being perfect dislocation loop clusters and tetrahedral precipitates, respectively. Some form of tiny micro-defect was also distributed preferentially in the vicinity of the Swirl pattern, but there was no detectable correspondence between hillocks and these micro-defects.

Tentative Analysis of Swirl Defects in Silicon Crystals T.W.Fan, J.J.Qian, J.Wu, L.Y.Lin, J.Yuan: Journal of Crystal Growth, 2000, 213[3-4], 276-82