ELECTRON-MICROSCOPY STUDY OF OXIDATION-INDUCED DEFECTS AT THE SILICONSILICON-DIOXIDE INTERFACE

It is shown by transmission and electron scanning microscopies and ene rgy-dispersive X-ray spectroscopy that the conditions of thermal annea ling and the initial surface damage influence the microstructure of th e silicon-silicon-dioxide interface and the silicon underlayers, espec ially the structure and chemical composition of defects. Annealing und err vacuum enhances the dislocation formation induced by diamond polis hing. Oxidizing annealing of similar samples induces stacking faults, while mechanochemically polished samples do not show any stacking faul ts after the same thermal treatment. Copper precipitation in {110} pla nes is observed. The shape of the precipitates depends on the density of nucleation sites in the near-surface layers as well as on the amoun t of contaminating copper: some small copper precipitates are detected when the silicon has been mechanically polished and oxidized, while g iant copper colonies are revealed when the silicon sample has been mec hanochemically etched.