'Umbrella'-like precipitates in nitrogen-doped Czochralski silicon wafers

摘要

Nitrogen effect on nucleation of oxygen precipitates in Czochralski Si has been investigated by transmission electron microscopy, Z-contrast imaging, and electron energy loss spectrometry (EELS). We have examined unusual "umbrella" shape oxygen precipitates in bulk of ingot in depths of more than 40 μm. Two predominant orientations of "umbrella" have been found along [110] and [-1-10] directions. We have investigated the distribution of nitrogen, oxygen, and interstitial Si by EELS profile taken simultaneously with HR Z-contrast image. The mechanism of nitrogen-enriched oxygen precipitates nucleation has been discussed.