Prevention of impurity gettering in the RP/2 region of ion implanted silicon by defect engineering

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 is controlled by the same mechanism working for excess vacancy generation. The obtained results directly relate the appearance of the RP/2 gettering effect to radiation-induced excess vacancies. Excess vacancies were found to be origin for the dominating gettering sites of Cu at RP/2. Moreover, it was shown that the undesired impurity trapping at RP/2 can 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 were determined for the additional Si+ implantation to remove Cu gettering at RP/2. If the threshold fluence necessary to remove the Cu gettering at RP/2 is exceeded, the excess vacancies are overcompensated and new interstitial-type dislocation loops form.