Light-beam-induced current measurements on copper–nickel co-contaminated Cz-silicon bicrystals

We report temperature-dependent LBIC-measurements on copper–nickel co-diffused Czochralski-silicon bicrystals focussing on the distribution and the recombination properties of the metal-precipitated defects. The samples had been hydrophobically wafer-bonded from two n-type materials with slightly different doping concentration and thermal history. LBIC analyses in cross-section geometry reveal substantially different spatial distributions of metal-related precipitates between the two crystals. This behaviour is explained by oxygen-related microdefects present in one wafer, acting as efficient nucleation sites. A precipitate-free zone was found below the surface but not beneath the bonding interface. At isolated colonies LBIC contrasts in the range of 50% have been observed indicating strong carrier recombination at such defects.