SIMS depth profiling of implanted helium in pure iron using CsHe+ detection mode

Helium distribution in implanted monocrystalline and polycrystalline Fe samples has been measured by secondary ion mass spectrometry (SIMS). The use of Cs+ primary ions in conjunction with the detection of CsHe+ molecular ions was shown to be an efficient method to overcome the very high first ionization potential of helium. The implantation ranges of 60keV He ions in samples are measured about 220nm in agreement with projected ranges calculated by TRIM. He concentrations at or above 5×1018at/cm3 (∼60ppm) were measured. This study confirms the paramount interest of SIMS as a direct He depth profiling technique.