Internal gettering efficiency in p/p+ and p/p- silicon epistructures

The efficiency of internal gettering vs. external and p(+) gettering has been investigated by EBIC contrast measurements in p/p(+) and p/p(-) epi Si on Cz substrates containing oxygen precipitates. The samples were not intentionally contaminated. It was seen that internal gettering also works in presence of back-side poly Si and high B concentration (p/p+ samples with high oxygen content and back-side poly Si) because of, on one hand, the high density of oxygen precipitates and, on the other hand, the low onset temperature for p(+) gettering. The metal undergoing internal gettering likely is Fe, though present in concentrations as low as 10(9)-10(10) cm(-3).