Ostwald ripening of Ge precipitates elaborated by ion implantation in SiO2

The kinetical behavior of Ge nanoparticles synthesized in SiO2 by ion impla ntation and annealing has been studied by transmission electron microscopy and electron energy loss spectroscopy measurements. The combination of both techniques allows to develop a new method for simultaneous evaluation of t he main parameters of the nanoparticles distribution (density and size) in an amorphous matrix. The number of Ge atoms contained within the precipitat es, as deduced from these parameters, agrees with the Ge content in the imp lanted layer as measured by secondary ion mass spectroscopy (SIMS), which g ives confidence on the proposed method. The obtained results indicate the e xistence of a conservative Ostwald ripening process. Finally, the activatio n energy for the precipitate growth has been deduced from the data. (C) 200 0 Elsevier Science S.A. All rights reserved.