Beam induced phase transformations and self annealing in as-implanted iron silicides

Using spatially resolved energy-loss spectroscopy, electron diffraction, and He+-ion channeling we have observed the evolution of α-Fe disilicide layers from primary crystallographically badly defined FeSi2 precipitates with increasing Fe dose in as-implanted specimens at constant target temperature. Increasing the Fe+ dose transforms secondary metallic α-FeSi2 first into semiconducting β-FeSi2 and then into FeSi. Elevated target temperature at constant dose also causes transformation of the secondary α-FeSi2 into β-phase. Results are interpreted in terms of beam induced crystallisation.