Oxidation-Induced Changes of Work Function and Interfacial Electronic States on Si(001) Surfaces Studied by Real-Time Ultraviolet Photoelectron Spectroscopy

Ogawa, Shuichi; Takakuwa, Yuji

doi:10.3131/jvsj.49.327

Cited by 2 publications

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References 16 publications

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“…Angle-resolved XPS was also employed to measure the depth profile of SiO near the SiO 2 surface to clarify the reaction between SiO and O 2 molecules in the SiO 2 film. 74) In this paper, we review the study of the unified Si oxidation reaction model mediated by point defect generation: The competition between the SiO 2 growth and decomposition, [74][75][76] the phase transitions in the surface oxidation, [77][78][79][80][81][82][83][84][85] the SiO 2 decomposition kinetics, 86,87) the lattice site of the adsorbed O atom, 88,89) the correlation between the SiO 2 growth rate and the SiO 2 decomposition rate, 90) the Si emission kinetics, 72,91) the self-accelerating oxidation, 92) the thermal strain-induced enhancement of dX O /dt, 93) the P O2 dependence of dX O /dt, 94) the temperature and P O2 dependence of dX O /dt during the layer-by-layer oxidation, 95) the oxidation reaction kinetics of the Si 1−x C x alloy layer (x ; 0.1) formed on Si(001) surfaces. 96) This review paper consists of five chapters.…”

Section: Introductionmentioning

confidence: 99%

Roles of strain and carrier in silicon oxidation

Ogawa

Yoshigoe

Tang³

et al. 2020

Jpn. J. Appl. Phys.

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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 SiO 2 /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 SiO 2 , thermal excitation of Si emission rate, and heat of adsorption. The band bending of the SiO 2 /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.

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Section: Introductionmentioning

confidence: 99%

Roles of strain and carrier in silicon oxidation

Ogawa

Yoshigoe

Tang³

et al. 2020

Jpn. J. Appl. Phys.

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Two-step model for reduction reaction of ultrathin nickel oxide by hydrogen

Ogawa

Taga

Yoshigoe

et al. 2021

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Nickel (Ni) is used as a catalyst for nitric oxide decomposition and ammonia production but it is easily oxidized and deactivated. Clarification of the reduction process of oxidized Ni is essential to promote more efficient use of Ni catalysts. In this study, the reduction processes of ultrathin oxide films formed on Ni(111) surfaces by thermal oxidation under vacuum and a hydrogen atmosphere were investigated by in situ time-resolved photoelectron spectroscopy. On the basis of these results, we propose a reaction model for the reduction of Ni oxide films. Our results show that the reduction of Ni oxide films on heating under vacuum does not yield a clean Ni(111) surface owing to formation of a residual stable suboxide structure on the Ni(111) surface. Conversely, in a hydrogen atmosphere of 1 × 10−5 Pa, the Ni oxide was completely reduced and a clean Ni(111) surface was obtained, even when heating below 300 °C. The reduction in a hydrogen atmosphere was best described by a two-step reaction model. The rate of the first step depends on the reduction temperature, and the rate of the second step depends on the H2 pressure. The rate-limiting process for the first step is surface precipitation of O atoms and that of the second step is dissociation of H2 molecules.

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Oxidation-Induced Changes of Work Function and Interfacial Electronic States on Si(001) Surfaces Studied by Real-Time Ultraviolet Photoelectron Spectroscopy

Cited by 2 publications

References 16 publications

Roles of strain and carrier in silicon oxidation

Roles of strain and carrier in silicon oxidation

Two-step model for reduction reaction of ultrathin nickel oxide by hydrogen

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