EXPERIMENTAL-STUDY AND MODELING OF STRUCTURE FORMATION IN BURIED LAYERS AT ION-BEAM SYNTHESIS

During ion beam synthesis of SIMOX structures a redistribution process is responsible for the modification of the implanted O+ profile towar ds a homogeneous buried layer of SiO2. This is known to be mainly due to Ostwald ripening. The first approach of our study of this highly co mplex system, both experimentally and theoretically, is devoted to the substoichiometric concentration range representing the wings of stoic hiometric layers. Our experiment shows that Ostwald ripening starts fr om precipitates of comparable size, homogeneously distributed througho ut the substoichiometric implanted layer. A computer simulation of Ost wald ripening of such an initial distribution of precipitates results in the self-organisation of structure in the precipitate distribution which can be related to the experimentally observed two band structure of precipitates. Thus it has been proven experimentally: (i) that the two band structure of precipitates must not originate from preferred precipitation in certain regions as proposed so far, and (ii) theoreti cally that a structure formation in the precipitate distribution may a rise from self-organisation during Ostwald ripening.