Abstract
Dislocations (of interstitial character) as well as cavities are known for their ability to getter impurities within Si. In order to determine the relative gettering strength we produced both dislocations and cavities at different depths within (1 0 0) Si. This was obtained by implantation and subsequent annealing of 3×10 16 (40 keV H)/cm 2 and 1×10 16 (140 keV Si)/cm 2 resulting in cavities and dislocations at depths of 400 nm and 200 nm, respectively. Fe or Cu was then implanted with a dose of 5×10 13 atoms/ cm 2 and an energy of 35 keV. By selective implantation of different areas, all possible combinations of impurities, dislocations and cavities were obtained within one Si-sample. The results show, clearly, that Cu-impurities are gettered totally by cavities (or open-volume defects), even when dislocations are also present. In contrast, Fe-impurities, which are released from traps near the surface during annealing, are gettered by both interstitial-based dislocations and open-volume defects. Secondary ion mass spectrometry and transmission electron microscopy analyses reveal defect-Fe-impurity interactions at the different trap sites.
Published Version
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