
257Impurities in Silicon Wafers
spectrophotometry and those obtained by the activation analysis method within a 40%
range in determining the carbon impurity concentration in silicon. The carbon content
of semiconductor-grade silicon was found to be on the order of a few ppma, which is in
disagreement with chemical analysis results. Quantication of carbon in silicon is still a
major topic of research. Many groups are actively working on this key material present in
silicon crystals [38–47], as is evident from the publications.
Three types of microdefects, formed by the agglomeration of either self-interstitials or
vacancies, have been observed ...