The Cu passivation of B in layer samples was investigated by using Schottky barrier structures which had been prepared by depositing Cu onto B-doped SiGe at room temperature. The B passivation occurred at room temperature, after Cu deposition and diffusion in the alloy. The Cu diffusivity was enhanced by dislocations, and retarded by an increased Ge content and/or compressive strain. It was proposed that the passivation mechanisms were similar to those in pure Si. That is, fast-diffusing interstitial Cu+ passivated the B acceptors by forming neutral B-Cu complexes.

Copper Passivation of Boron in SiGe Alloys and Boron Reactivation Kinetics. M.Barthula, M.O.Aboelfotoh, F.Meyer: Microelectronic Engineering, 2001, 55[1-4], 323-8