In this paper we review the study of the unified Si oxidation reaction model mediated by point defect generation, in which O-2 dissociative adsorption occurs at dangling bonds of point defects (emitted Si atoms and vacancies) at the SiO2/Si interface, and the point defect generation rate is given by a combination of oxidation-induced strain, thermal strain due to the difference in thermal expansion coefficient between Si and SiO2, thermal excitation of Si emission rate, and heat of adsorption. The band bending of the SiO2/Si interface is caused by the electron and hole trapping at the vacancy for n- and p-Si substrates, respectively, leading to the charged states with unpaired electrons that is responsible for the dissociative adsorption of O-2 molecule. Since P-b0 and P-b1 centers with unpaired electron are not concerned with the charge transfer of band bending, they are also the active sites for O-2 dissociative adsorption. (C) 2020 The Japan Society of Applied Physics