Implantation and grain growth in ni thin films induced by Bi and Ag ions

Thin (25–60 nm) Ni films deposited on NaCl at 300 K. and 673 K have been implanted with 40–200 keV ions of Bi and Ag. Rutherford backscattering analysis has been used to measure the film thickness and retained Ag and Bi atom concentrations whilst electron microscopy has been used to determine the microstructure and crystallographic relationships. A Bi concentration of 7.4 at.% was reached in the Ni films without observable precipitation of a second phase. By contrast, precipitates were observed in Ag implanted Ni films when the Ag concentration exceeded 4 at.%. Recrystallization and grain growth were observed in the ion bombarded region. The average grain diameter was found to increase linearly with implant dose and the growth rate increased linearly with the energy deposited into elastic collisions. For doses ≳ 1.5 × 1016cm−2 microtwins were observed and a 〈110〉 plate fibre texture developed. This resulted in some channeling of the incident ions and to selective grain sputtering.