Impurity gettering by high-energy ion implantation in silicon beyond the projected range

Deep gettering layers have been formed in Si wafers by MeV implantation of Si+ and P+ ions, followed by annealing. Samples have been subsequently cont aminated with Cu. Secondary ion mass spectrometry analysis reveals for P im plants gettering of Cu atoms in regions significantly deeper than the proje cted ion range R-P and formation of a separate Cu gettering band there. We call this phenomenon the "trans-R-P effect." The results obtained indicate the presence of an appreciable amount of defects in the region beyond R-P. Their gettering ability is much higher than that of the implanted gettering layer at R-P. The size of these deep defects is below the resolution limit of transmission electron microscopy. We suggest that they are interstitial s and/or small interstitial clusters. An explanation of the mechanism respo nsible for their migration from R-P into the trans-R-P region and their clu stering is proposed. (C) 1999 American Institute of Physics. [S0003-6951(99 )00948-1].