Precipitate engineering in GaAs studied by laser scattering tomography

Annealing experiments were carried out with semi-insulating LEC GaAs. The v olumes of the precipitates were determined by an advanced technique of lase r scattering tomography (LST) qualified for quantitative volume measurement s and their statistical relevant evaluation. The dependence of the volume d istributions of precipitates on annealing conditions is presented. The depe ndence of the total volume of the precipitate ensemble on hold temperature and time is shown. The experimental results cannot be explained completely in the framework of Ostwald ripening of the As precipitates. A behaviour no t described earlier has been observed: at cooling inside the assumed homoge neity range of GaAs the growth of As precipitates followed by their dissolu tion. (C) 2001 Published by Elsevier Science B.V.