Determination of chlorine distribution in silicon dioxide by neutron activation

A neutron activation method for the determination of chlorine distribution in silicon dioxide on the surface of Si wafers has been developed. After irradiation of the sample with a standard, successive layers are removed from the oxide surface by chemical etching and the chlorine content in the solutions obtained is determined gamma-spectrometrically. Using a Ge(Li) detector, a lower limit of determination of 1.0·10⁻⁷ g was obtained. This limit can be improved by using a NaI(Tl) detector. The error of chlorine determination is discussed.