Relation Between Oxidation Rate and Oxidation-Induced Strain at SiO₂/Si(001) Interfaces during Thermal Oxidation

To experimentally verify the Si oxidation reaction model mediated by point defect (emitted Si atoms and their vacancies) generation due to oxidation-induced strain, real-time photoelectron spectroscopy using synchrotron radiation was employed to simultaneously evaluate the amount of oxidation-induced strained Si atoms at the SiO 2 /Si interface, oxidation state, and oxidation rate during oxidation on n-type Si(001) surfaces with O 2 gas. It is found that both the oxidation rate and the amount of strained Si atoms at the completion of the first-oxide-layer growth decrease gradually with increasing temperature from 300 to 550 °C, where the oxide grows in the Langmuir-type adsorption manner. It is found that the interface strain and oxidation rate have a strong correlation. We discuss the reason for the oxide coverage and oxidation temperature dependences of interfacial strain from the viewpoint of the behavior of adsorbed oxygen during the first-oxide-layer growth.