Exafs Studies of Ion Implanted Bismuth

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AbstractMagnetorefiection and preliminary Rutherford Backscattering channeling experiments indicate that point defects induced in the bismuth lattice by ion implantation are largely annealed out during the implantation process due to its low melting temperature of 271.3°C. These experiments also show that the implanted ions cause long range strains in the crystal. Single crystal bismuth samples have been implanted at low temperatures (from 273°K down to 77°K) with 75 As to a total fluence of 5 × 1016/cm2 at energies ranging from 50 keV to 200 keV to yield an approximately constant arsenic profile from the sample surface to a depth of 625 Å. To study the local environment of the implanted As ions, EXAFS measurements have been made at the Cornell High Energy Synchrotron Source (CHESS). From these data, we obtain a comparison of the As nearest neighbor distances in samples implanted at different temperatures. We discuss the effect of sample temperature during implantation on these properties. This work represents the first use of EXAFS to characterize annealing of implantation-induced lattice defects during the process of ion implantation.