Combined XBIC/μ-XRF/μ-XAS/DLTS investigation of chemical character and electrical properties of Cu and Ni precipitates in silicon

摘要

Combination of DLTS method and synchrotron-based analytical microprobe techniques was used to study the precipitation of Cu and Ni atoms at two kinds of structural defects in silicon lattice: dislocation network created by direct wafer bonding and oxygen-induced microdefects. Results of our measurements revealed the difference in the preferred precipitation places: Ni particles in form of NiSi_2 were found only at the dislocation network, while Cu particles in form of Cu_3Si were found both at the dislocation network and at thernoxygen-induced microdefects. DLTS measurements showed Ni acceptor levels in Ni contaminated sample and a broad band related to Cu precipitates in Cu contaminated one. In case of simultaneous Cu and Ni contamination NiSi_2 and Cu_3Si precipitates were found definitely at the same places indicating therefore that the metals interact during precipitation. DLTS showed the superposition of spectra for only Ni and for only Cu contaminated samples.