Effect of oxygen on the formation of end-of-range disorder in implantation amorphized silicon

Formation of End-of-Range (EOR) disorder was studied in (100)-oriented silicon, when subjected to amorphization by implantation of Gehighplus ions, followed by a 10 s Rapid Thermal Annealing (RTA) at 1050 degreeC. XTEM, RBS/channeling, and SIMS were used to analyze Czochralski grown (CZ) silicon wafers with oxygen concentrations of 6.5, 7.0, and 8.0 X 10high17/ccm and Float Zone (FZ) silicon, as "low oxygen" wafers. Amorphization on neighboring parts of the 4" wafers was made either by 60 keV Gehighplus implantation or by 110 keV Gehighplus implantation and by sequential (60 keV plus 110 keV) Gehighplus implantation. Parts of each wafer were additionally implanted with 13 keV boron. In FZ silicon, no defects were found for 60 keV Gehighplus implantation and RTA at 1050 degreeC. For 110 keV Gehighplus and sequential (60 keV plus 110 keV) Gehighplus implantation in FZ- silicon the majority of the samples showed perfect annealing. Two wafers, however, subjected to sequential implantation still contained defects but with a defect density that was one order of magnitude lower than for CZ wafers. For one of them, not even a continuous layer of defects was formed. In contrast, CZ wafers contained defect bands, except for the 60 keV Gehighplus implantation (in accord with the findings of Ozturk et al., IEEE Trans. on Electronic Dev. 35, 659 (1988)). The presence of boron had no visible effect on the defect structure.