The interaction between Cu and irradiation-induced defects was investigated by using Schottky-barrier structures which were formed by depositing Cu onto n-type or p-type Si which had been bombarded with 2MeV electrons at room temperature. It was found that the annealing rate of the di-vacancy centers (V2) was anomalously high, at temperatures below 150C, in both n-type and p-type material. This was attributed to passivation of the V2 centers, by the highly mobile Cu, via the formation of neutral complexes. A prominent level which was located at 0.52eV above the valence-band edge appeared in p-type material after Cu deposition at room temperature. It was suggested that this level originated from a complex that was formed by reaction between Cu and the C-O centers which gave rise to the so-called ordinary irradiation-induced level at Ev + 0.35eV. This level, which was normally stable at up to about 350C, annealed out rapidly at 100C via the formation of the Cu-associated level at Ev + 0.52eV which disappeared during silicide formation. The present results also showed that, contrary to previous conclusions, no injection of Si self-interstitials into the Si substrate took place during formation of the metal-rich silicide, Cu3Si.

M.O.Aboelfotoh, B.G.Svensson: Physical Review B, 1995, 52[4], 2522-7