Initial oxidation of Si(100)2 x 1 by ozone: Transition of growth kinetics from adsorption to ultrathin film growth

We have investigated the initial oxide growth kinetics on Si(100)2x1 by highly concentrated ozone (>80%) using X-ray photoelectron spectroscopy. Initial oxidation of <0.6 nm was found to proceed in accordance with Langmuir kinetics. However, a growth mode changed into linear kinetics at the oxide thickness of 0.6 nm on the surface at >550 degrees C, while no further growth of oxide films >0.6 nm was observed on the surface at <500 degrees C under the same pressure condition. This clear transition of kinetics has contributed to the successful growth of an oxide film >0.6 nm which is difficult to synthesize using molecular oxygen under the same processing conditions.