INFLUENCE OF TRANSITION-METAL IMPURITIES ON OXYGEN PRECIPITATION IN CZOCHRALSKI-GROWN SILICON

Oxygen precipitation in Czochralski-grown silicon intentionally contam inated with Cu or Fe is investigated by means of Fourier-transform inf rared spectroscopy, transmission electron microscopy, and the electron -beam-induced-current technique. It is found that oxygen precipitation is not influenced by Cu impurities, but is enhanced significantly by Fe impurities even if the concentration of Fe is much lower than that of Cu in Si. Cu forms precipitate colonies of a low density and a larg e size, and does not react with minute oxygen precipitates existing in as-grown specimens. On the contrary, Fe precipitates on them and form s Fe decorated silica particles of a very high density, which serve as the efficient sites for the nucleation of oxygen precipitates. (C) 19 96 American Vacuum Society.