Damage formation and annealing studies of low energy ion implants ...

peak gives a dose of 1.2E14 cm -2 – 1.7E14 cm -2 which is between 9 - 12 % of the
implanted F. The dose measured by SIMS suggests total dose retention. F appears to be
trapped at the oxide interface.
For the non-PAI samples in Figure 7.4b), the as-implanted sample displays a
slight channelling tail and is otherwise the same as the PAI sample. For samples
annealed at high temperatures the F migration to the surface is also observed. However
the deeper migration observed with PAI samples does not occur in non PAI samples.
The only variation is with the sample annealed at 600 °C, in which a double peak is
observed. The second peak is centred around a depth of 7-8 nm. This behaviour is not
too unusual and can be attributed to trapping of some F around the original a/c interface
which is consistent with previous studies (4). The MEIS profile in Figure 7.4c) indicates
the depth of the original a/c interface around 7 – 8 nm which is indeed consistent with
the F trapping result. Returning to the PAI samples in figure 7.4a), it is worth
mentioning that the second deeper damage peak at 12 – 13 nm cannot be attributed to
trapping at the original a/c interface, which is much deeper in the PAI samples.
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