US Patent 7208377 Silicon oxidation method

A method for forming, by thermal oxidation, a silicon oxide layer on an integrated circuit including three-dimensional silicon patterns, includes implanting a first element according to a first angle with respect to a horizontal direction. The first element is electrically neutral and has a first effect on the growth rate of a thermal oxide on silicon. A second element is implanted according to a second angle with respect to the horizontal direction. The second element is electrically neutral and has a second effect complementary to the first effect on the growth rate of a thermal oxide on silicon. The second angle is distinct from the first angle, and one of the first and second angles is a right angled. The silicon is thermally oxidized.