Oxygen precipitation in heavily boron-doped silicon crystals

Abstract

Transmission electron microscopy was applied to study oxygen precipitation in P+ wafers by comparison with that in P− wafers grown in the same puller under the same growth schedule. Besides the higher precipitate density in P+ wafers for all heat treatments, it was shown that nucleation centers can be easily re-established in P+ wafers at a low temperature after a prior denuding anneal. The precipitate morphology was found to depend on the precipitate growth rate and/or the presence of impurities. The morphology evolution from a small polyhedron to a large plate during the precipitate growth is proposed to explain the observed shapes.