Evidence for a dose dependence for thermal redistribution of implanted silicon in SiO2

The redistribution of implanted 30Si atoms in isotopically purified 28SiO2 thermal oxide is studied as functions of temperature and implanted dose. The results clearly evidence a diffusion enhancement, which is more pronounced at low temperature and high dose. The results are consistent with the simple picture that the redistribution is governed by a Si interstitial diffusion mechanism, which can be slowed down by the presence of residual impurities.