The energy dependence of excessive vacancies created by high energy Si+ ion implantation in Si

We have used molecular beam epitaxy grown Sb markers within Si to detect vacancy fluxes created by high energy Si+ ion implants at various energies. Our experiments show that for a constant ion fluence of 1 X 10(15) cm(-2), the number of free vacancies created by ion implantation, followed by annealing at 900 degrees C, increases with implantation energy. This is in contrast to the instantaneous vacancy creation rate during ion bombardment at the surface, which decreases with increasing ion energy. The possible mechanisms are discussed based on the separation distance between excessive interstitials (at the projected range of ions) and vacancies (near the surface), and the interaction between free vacancies and vacancy clusters. (c) 2005 Elsevier B.V. All rights reserved.