Proximity gettering of transition metals in separation by implanted oxygen structures

The gettering behavior of Cu and Fe in ion beam synthesized silicon on insulator (SOI) material incorporating a buried oxide layer is investigated before and after the formation of deep gettering zones by either C or He implantation. Secondary ion mass spectroscopy (SIMS) analysis is employed to obtain information as to the C, O, Fe, and Cu depth distributions. It is shown that the proximity gettering approach using C and He renders the possibility of removing and stabilizing metal contaminants not only away from the near-surface region, but also remote from the buried oxide/substrate interface to which they normally segregate in the absence of efficient implantation induced gettering sinks. C implants are found to have better gettering efficiency as they getter both Cu and Fe whereas He implants getter Cu only. In addition, the C implant dose needed to achieve one and the same gettering effect is an order of magnitude lower than the He dose.