ENHANCED SURFACE-INTERFACE RECOMBINATION AND SURFACE INVERSION OF NI DECORATED SI SI(GE)/SI HETEROSTRUCTURES/

Electron beam induced current variations in images of strain relaxed e pitaxial Si/Si(Ge)/Si wafers deliberately contaminated with nickel fro m the backside are reported for different contamination levels. Strong recombination contrast due to NiSi2 precipitates was observed both at the top Si surface and along buried interfacial misfit dislocations. A surface conductivity inversion from n to p type was obtained for the high level Ni contaminated sample. A theoretical analysis based on th e presence of a surface potential due either to a metal-silicon Schott ky contact, or to the accumulation of charged traps is used to explain the observed effects.