Proximity gettering of silicon wafers using CH3O multielement molecular ion implantation technique

Abstract

We investigated the fundamental characteristics of a CH3O-ion-implanted silicon epitaxial wafer with our previously developed multielement molecular ion implantation technique and compared this technique with a conventional implantation technique, i.e., “carbon cluster ion implantation”. We found that the CH3O ion projection range has a 10-fold higher oxygen concentration than the carbon cluster ion projection range after epitaxial growth. We also found 50 nm silicon {111} stacking faults in the CH3O ion projection range. Such defects were not observed in the carbon cluster ion projection range. From nickel gettering test results, proximity gettering of nickel contaminations by CH3O ion implantation was found to be more effective than that by C2H3 ion implantation. Therefore, we speculate that the CH3O ion projection range improves the gettering capability of metallic impurity contaminants through the formation of complex point defects formed by vacancies and that oxygen implanted at a high concentration and silicon {111} stacking faults are new gettering sinks.