Method for determining impurities in epitaxial silicon crystals

摘要

A laser beam is directed onto an epitaxial silicon crystal grown on a silicon crystal substrate at the temperature of liquid helium and the spectra of the luminescent light radiated from the crystal and the substrate are analyzed to determine the kind and concentration of impurities in the epitaxial silicon crystal. In particular, a photo luminescence intensity ratio of an impurity within the crystal substrate and an impurity within the epitaxial crystal is graphically related to the concentration of the impurity within the epitaxial crystal such that the concentration levels of the impurity within the epitaxial crystal may be determined as a function of the photo luminescence intensity ratio.