PIXE ANALYSIS OF HEAVY-ELEMENTS IN SILICON USING MEV HEAVY-ION BEAMS

Detection limits of heavy elements such as Fe or Cu near the surface o f silicon was investigated by PIXE using slow heavy ions (< 90 keV/amu ). Fe atoms were implanted in silicon at 343 keV energy to a dose of 1 x 10(13)-1 x 10(15) Fe/cm(2) and Cu was introduced in silicon to the dose of 5 x 10(14) Cu/cm(2). PIXE spectra were obtained by 5.2 MeV Ni- 58(3+) and Ge-74(3+) beams in order to enhance the yield of Fe or Cu K X-ray by MO process. The results were compared with those obtained by a 2 MeV proton beam. In the case of slow heavy ion impact, bremsstahl ung background above 5 keV was much lower than that of protons. Moreov er, Fe K alpha X-ray production in Fe implanted silicon was enhanced b y using the 5.2 MeV Ni-58(3+) beam. As a result, the detection limit o f Fe in silicon was successfully improved. However, Cu K alpha X-ray p roduction in Cu contaminated silicon was not so enhanced by using the 5.2 MeV Ge-74(3+) beam and the detection limit could not be improved.