A study was made of the origin of defects in oxide which had been thermally grown on Czochralski Si substrates. The samples were submitted to Cu decoration in order to locate oxide defects, focused ion beam etching was used to mark them, and substrate thinning was used to prepare the samples for transmission electron microscopy. Polyhedron structures with sizes that ranged from 150 to 300nm were found in the underlying Si substrate surface layer, just below the oxide defects. Two polyhedron structures which were superposed on each other were also observed. It was suggested that these structures were related to the presence of O precipitates. The oxide defects were thought to arise from an oxide thinning which occurred at the edge of the Si-substrate surface that was adjacent to the octahedron structures.

M.Itsumi, M.Tomita, M.Yamawaki: Journal of Applied Physics, 1995, 78[3], 1940-3