TRAPPING MECHANISMS BY CAVITIES FOR METALLIC IMPURITIES IN MONOCRISTALLINE SILICON

摘要

Taking stock of "clean" cavity energies, we conclude that the most important one which controls the cavity shape is the surface energy. Thus, we introduce a cavity shape factor η defining a constant cavity volume. The variations of its corresponding surface energy with η give the cavity equilibrium shape which is taken as reference. Further simulations are performed, tuning the specific surface energy of the cavity vicinal surface γ_m. The calculations reveal that a decrease of only 0.2 Jm~(-2) of γ_m is enough to get a drastic impact on the cavity morphology. They demonstrate that cavity shape modification must proof the occurrence of chemisorption. Effectively we experimentally observed such shape transformation when the mean coverage of cavities reaches at least few percents. The bi-dimensional or three-dimensional phase formation depends on the metal flux arriving at cavities, on the local coverage of the vicinal surface, and on the metal specific surface energy.