The Fe ions were implanted into thermally grown silica films, to a dose of about 6.5 x 1016/cm2, by using a metal-vapor vacuum-arc ion source and an accelerating voltage of 62kV. Structural evolution of the film during post-implantation annealing was studied by means of X-ray diffraction, Rutherford back-scattering spectroscopy, X-ray photo-electron spectroscopy and atomic force microscopy. It was found that the implanted Fe atoms gradually diffused out of the film and aggregated to form particle islands on the film surface after annealing. Out-diffusion and island formation were particularly marked when the annealing temperature was increased to 800C. It was demonstrated that, in the early stages of annealing, the growth of Fe islands depended closely upon the out-diffusion of the implanted Fe atoms, and that the size and areal density of the islands increased progressively with increasing annealing time. After a certain time, the size of the islands continued to increase, but the areal density decreased significantly; thus implying that most of the implanted Fe atoms had diffused out of the film. The islands could then grow further by consuming smaller ones via surface diffusion.

Aggregation and Out-Diffusion of Iron Atoms for Fe Ion-Implanted Silica Films. X.Ding, M.F.Chiah, W.Y.Cheung, S.P.Wong, J.B.Xu, I.H.Wilson, H.Wang, L.Chen, X.Liu: Journal of Applied Physics, 1999, 86[5], 2550-4