Low energy O induced redistribution of nanosized Au inclusions in an oxide layer grown on Si(1Â 0Â 0)

Implantation of 32 keV Au− ions, at the rate of ∼2 × 1013 ions cm−2 s−1, to a dose of 8 × 1016 ions cm−2, into a thermally grown oxide layer on Si(1 0 0), has been found to produce Au nanoclusters with a bimodal size distribution. Rutherford backscattering spectrometry and transmission electron microscopy have been used to characterize the samples. The as-grown nanocluster distribution has ∼6 nm size clusters in the near surface region with a tail of smaller clusters extending into the oxide matrix. A further O implantation (dose in the range of 5 × 1015 to 5 × 1016 atoms cm−2) has been found to result in a breakup of larger Au nanoclusters. This can be understood in terms of the formation of displacement spikes coming from the second implantation. Annealing, both the as-implanted and subsequent high dose O implanted samples, at 800 °C for 1 h has been found to result in a growth in the nanocluster size the later showing a more uniform distribution.