Layer-resolved kinetics of Si oxidation investigated using the reflectance difference oscillation method

Abstract

Dry oxidation kinetics of the Si(001) surface has been investigated using reflectance difference oscillation to resolve atomic-scale phenomena. The activation energy for oxidation has been found to increase as the oxide-Si interface moves in the depth direction, reaching the value for bulk oxidation, 2.0 eV, at the third layer from the surface. The nonlinear dependence of the oxidation rate on the ${\mathrm{O}}_{2}$ pressure, which was reported for bulk oxidation, has also been observed in the second- and third-layer oxidation. Chemical reaction and mass transport mechanisms for this initial oxidation regime are discussed.