Electrically inactive dopants in heavily doped as-grown czochralski silicon

To determine the electrically inactive fraction of As or P in heavily doped as-grown Czochralski Si4-point resistivity and SIMS measurements were carried out. No clear trend for the electricalinactive fraction was found with an increasing dopant concentration, though a mean electricalinactive fraction of 11.5% for As doping could be determined.Experimental results on a dopant-vacancy complex in as-grown Si are scarce, hence temperature dependentpositron annihilation lifetime spectroscopy (PALS) was carried out on several heavily Asand P doped as-grown Si samples. The measured average positron annihilation lifetime Ïav isbetween 218 ps and 220 ps. No temperature dependent effect on Ïav could be observed. Therefore, itcan be concluded that in the studied doping range the dopant-vacancy complexes do not exist. Thereason for the inactivation of the dopant has to be found elsewhere. A possible explanation can bethe formation of dopant precipitates.