Range profiles and thermal release of ³He implanted into various nickel-based amorphous alloys

The behavior of ³He in the amorphous alloys Ni_75.1Cr₁₄P_10.1C_0.08, Ni_63.5Zr_36.5 and Ni_87.7P_12.3 is investigated. The samples were implanted with 150 keV ³He ions with doses of 1 × 10¹⁶ and 5 × 10^{16 3}He/cm². The samples were isochronally annealed at several consecutive stages up to their crystallization temperatures. After each annealing stage, ³He depth profiles were measured by a thermal-neutron-induced nuclear-reaction technique called neutron depth profiling (NDP). The maximum ³He release (∼20%) was observed for the Ni_63.5Zr_36.5 sample and it occurred before crystallization. Smaller but measurable amounts of ³He were released from most other combinations of sample material and implant doses. The ³He release that we observed is controlled by a detrapping process, and there are indications that it is dependent on the implantation dose. In addition to ³He release measurements, our study yielded a determination of projected depths of ³He ions with an initial energy of 150 keV in the alloys studied. The most probable range values are: 320 ± 21 nm for Ni_75.1Cr₁₄P_10.1C_0.08, 378 ± 34 nm for Ni_63.5Zr_36.5 and 375 ± 29 nm for Ni_87.7P_12.3.