Si+ ion implantation into Si under inclined incidence angle was applied to demonstrate that Cu gettering in the region around half of the projected ion range, RP/2, of ion-implanted Si was controlled by the same mechanism working for excess vacancy generation. The obtained results directly relate the appearance of the RP/2 gettering effect to the radiation-induced excess vacancies. Excess vacancies were found to be the source of the dominating gettering sites of Cu at RP/2. Moreover, it was shown that the undesired impurity trapping at RP/2 could be prevented by means of additional Si+ implantation into the vacancy-rich region of ion-implanted Si to balance the excess of vacancies. The parameters in order to remove Cu gettering at RP/2 were determined for the additional Si+ implantation. If the threshold fluence necessary to remove the Cu gettering at RP/2 was exceeded, the excess vacancies were overcompensated and new interstitial-type dislocation loops form.

Prevention of Impurity Gettering in the RP/2 Region of Ion-Implanted Silicon by Defect Engineering. R.Kögler, A.Peeva, J.Kaschny, W.Skorupa, H.Hutter: Nuclear Instruments and Methods in Physics Research B, 2002, 186[1-4], 298-302