ANOMALOUS DIFFUSION EFFECTS IN ION-IMPLANTED MGO SINGLE-CRYSTALS

The effects of niobium and rubidium ion implantation on monocrystalline (100) MgO slices have been investigated using Rutherford backscattering spectrometry in channeling geometry (RBS), electron spectroscopy for chemical analysis (ESCA) and optical absorption measurements. Analysis of the implantation profiles have been performed on samples implanted at 300 K with energies of 150 and 320 keV and doses ranging from 2 X 10(15) to 2 X 10(17) ions cm-2. For doses above 10(16) ions cm-2, the implantation profiles differ significantly from theoretical predictions of the "TRIM" code and exhibit a marked depth diffusion effect of implanted particles. Moreover, a particularly high fraction (between 60 and 95%) of implanted atoms in substitutional sites is evidenced. It has to be noticed that even for the highest doses the amorphization of the implanted layer does not occur. The different chemical states of atoms in the implanted layers investigated by ESCA and optical measurements have been correlated with RBS results in order to precise the anomalous diffusion effects of implanted species.