Stress inversion from initial tensile to compressive side during ultrathin oxide growth of the Si(100) surface

We report the real-time observation of the stress change during sub-nanometer oxide growth on the Si(100) surface. Oxidation initially induced a rapid buildup of tensile stress up to -1.9 × 10⁸ N m ^-2 with an oxide thickness of 0.25 nm, followed by gradual compensation by a compressive stress. The compressive stress saturated at 5 × 10⁷ N m^-2 for an oxide thickness of 1.2 nm. The analysis, assisted by theoretical study, indicates that the observed initial tensile stress is caused by oxygen bridge-bonding between the Si dimers. Atomistic model calculations considering mutually orthogonal orientations of the Si(100) surface structure reproduce the stress inversion from the tensile to the compressive side.