Suppression of Secondary Defects in Silicon by Carbon Implantation

Abstract

AbstractWe have examined the role of co-implanted carbon in suppressing the formation of secondary defects in self-ion irradiated Si(100). Implantation of 540 keV energy Si ions to a fluence of 1015 cm-2 followed by a 900°C, 15 minute anneal leads to the growth of an extended defect band at the end-of-range. Range matched carbon co-implantation can be used to modify this defect development dramatically. While direct co-implantation of carbon and silicon ions has no apparent effect on the formation of extended defects, such formation can be suppressed when the implanted C is incorporated substitutionally into the silicon lattice. Ion channelling and nuclear reaction analysis show that substitutional carbon is removed from substitutional sites during Si ion irradiation. In this case, it is proposed that excess interstitial silicon ions which normally lead to the growth of secondary defects will occupy the lattice sites previously occupied by carbon ions.