Oxide ridge formed around octahedral void defects on (001)-oriented Czochralski silicon

We found that thermal oxidation of (001)-oriented Czochralski silicon produ ces oxide ridges which surround the oxide pits above the grown-in defects ( or octahedral void defects), whereas thermal oxidation of (111)-oriented Cz ochralski silicon produces oxide pits solely above the octahedral void defe cts. When the thermal oxide layers on (001)-oriented silicon were 400 nm, t he heights of the oxide ridges were about 10-20 nm. Considering that the si de walls of the octahedral void defects are (111) oriented, we assume that the oxidation rate of (111)-oriented silicon exceeding that of (001)-orient ed silicon is closely related to the formation of oxide ridges. (C) 1999 Am erican Institute of Physics. [S0021-8979(99)02516-5].