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

Abstract

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, R P/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 R P/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 R P/2. Moreover, it is shown that the undesired impurity trapping at R P/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 in order to remove Cu gettering at R P/2 are determined for the additional Si + implantation. If the threshold fluence necessary to remove the Cu gettering at R P/2 is exceeded, the excess vacancies are overcompensated and new interstitial-type dislocation loops form.