Trans-projected-range effect in proximity gettering of impurities in silicon


Trans-projected-range effect in proximity gettering of impurities in silicon

Gueorguiev, Y. M.; Kögler, R.; Peeva, A.; Panknin, D.; Mücklich, A.; Yankov, R. A.; Skorupa, W.

Deep gettering layers have been formed in n-type Si wafers by high-energy ion implantation of Si+, P+, Ge+ and As+ and subsequent annealing. The samples have been then contaminated with Cu by implanting the impurity into the backface and an additional thermal treatment. The resulting copper depth profiles measured by secondary ion mass spectrometry show strong gettering of Cu well behind the projected ion range Rp and formation of a separate gettering band therein. We call this phenomenon the "trans-Rp effect". It has been observed for P and As implants, whereas for Si and Ge implants it was missing. This effect indicates the presence of a significant amount of defects much deeper than Rp. The size of these defects is below the resolution limit of our transmission electron microscopy analysis and we suggest that they are small interstitial clusters. Their gettering ability should be higher than that of the extended defects at Rp since the amount of Cu atoms gettered beyond Rp is much greater than that in the implanted gettering layer. A mechanism of the defect formation and clustering in the trans-Rp region is proposed, and an explanation is given of the differences in the results for the P and As implants.

Keywords: Ion implantation (61.72.Q); Defect formation and annealing (61.72.C); Indirect evidence of defects (61.72.H); Defects diffusion (66.30.L); Gettering (61.72.T)

  • Contribution to proceedings
    SIXTH INTERNATIONAL CONFERENCE ON ELECTRON BEAM TECHNOLOGIES EBT'2000, 4 - 7 June 2000, Varna, Bulgaria

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Publ.-Id: 3381