Roles of strain and carrier in silicon oxidation

In this paper we review the study of the unified Si oxidation reaction model mediated by point defect generation, in which O₂ 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 O₂ 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 O₂ dissociative adsorption.