A copper- and boron-related defect in silicon

The resistivity of boron-doped silicon can be significantly increased by polishing such material with an appropriate amine- and copper-containing slurry. This effect is ascribed to a passivation of the boron acceptors by a defect produced or introduced by the polishing process. Three new, so far unknown localized vibrational modes at 691, 720, and 1038 cm^–1 are observed in highly boron-doped silicon samples after such a polishing treatment. Two of these localized modes can be identified as due to a boron-containing defect. High concentrations of copper found in the samples after appropriate polishing indicate a participation — either directly or indirectly — of this metal in the passivation process.