Oxygen precipitation in nitrogen-doped Czochralski silicon

Oxygen precipitation in nitrogen-doped Czochralski (NCZ) silicon has been i nvestigated by one-step and two-step annealing. It was found that nitrogen in NCZ silicon enhanced oxygen precipitation at lower temperatures ( < 750 degrees C), while it had no influence on oxygen precipitation at higher tem peratures. We considered that nitrogen could enhance the nucleation of oxyg en precipitation, rather than its growth. After two-step annealing, the sam ples were observed by means of a transmission Electronic Microscope (TEM). New morphology of oxygen precipitates was revealed. The size of the oxygen precipitates was about 300-500 A. It is suggested that nitrogen interacted with oxygen to form nitrogen-oxygen complexes as heterogeneous nuclei which enhanced nucleation of oxygen precipitates. (C) 1999 Elsevier Science B.V. All rights reserved.