It was recalled that octahedral structures had recently been found in Czochralski Si substrate surface layers, just beneath oxide defects. An attempt was made to characterize these structures by means of transmission electron microscopy and energy-dispersive X-ray spectroscopy. The results indicated that the structure was full of vacancies; contrary to previous results which had suggested that the octahedral structures which had been found in bulk Si were filled with amorphous SiO2. A model was proposed for the formation of an octahedral structure with many vacancies.

M.Itsumi, H.Akiya, T.Ueki, M.Tomita, M.Yamawaki: Journal of Applied Physics, 1995, 78[10], 5984-8