Systematic low-high 2-step, and high-low-high 3-step, annealing methods were used to investigate the micro-defects which were generated in wafers of Czochralski-type material. The defect microstructure was found to be affected by the low-temperature annealing time. Cluster precipitates predominated in samples that received no, or short-term, nucleation annealing. Cluster precipitates disappeared, and dispersed precipitates predominated, in samples that received somewhat longer nucleation annealing. Cluster precipitates, entangled with dislocations, were annihilated during extended low-temperature annealing. It was suggested that interstitial type-A swirl defects were the nucleation centers for cluster precipitates. The annihilation of A-swirl defects was proposed in order to explain the lack of formation of cluster precipitates during 2-step annealing.

C.Y.Kung, C.M.Liu, W.Hsu, R.H.Horng: Journal of Applied Physics, 1998, 83[1], 56-9