Effect of the SiO2/Si Interface on Self-Diffusion in SiO2 Upon Oxidation

Masashi Uematsu; Kenzo Ibano; Kohei M. Itoh

doi:10.4028/www.scientific.net/DDF.273-276.685

Paper Titles

High-Temperature Oxidation of Fe- Si Alloys in the Temperature Range 900-1250°C
p.661

Diffusion of ⁸Li Short-Lived Radiotracer in Li Ionic Conductors of NaTl-Type Intermetallic Compounds
p.667

Thermal-Mechanical Responses of Ti-6Al-4V during Orthogonal Cutting Process
p.673

Mass Transfer Coefficients during Steel Decarburization in a RH Degasser
p.679

Effect of the SiO₂/Si Interface on Self-Diffusion in SiO₂ Upon Oxidation
p.685

Modelling of Stable Fission Gases Diffusion in UO₂ Nuclear Fuel
p.693

Computational Study of Heat Transfer in Honeycomb Structures Accounting for Gaseous Pore Filler
p.699

Study of Distribution of Impurity Atoms in Metallurgical Macrodefects
p.707

Evolution of the Enriched Layer at the Oxide/Metal Interface during Oxidation of Recycled Steels with Copper and Copper+Nickel Residuals
p.713

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Effect of the SiO₂/Si Interface on Self-Diffusion in SiO₂ Upon Oxidation

Abstract:

The effect of the SiO2/Si interface on Si self-diffusion in SiO2 during thermal oxidation was investigated using silicon isotopes. Samples with natSiO2/28Si heterostructures were oxidized at 1150 ~ 1250 °C and the 30Si diffusion in 28SiO2 during the thermal oxidation was investigated by secondary ion mass spectrometry (SIMS) measurements. Near the SiO2/Si interface, a significant profile broadening of the 30Si isotope from natSiO2 toward the newly grown 28SiO2 was observed. This 30Si self-diffusivity sharply decreases with oxidation time and hence with increasing distance between 30Si diffusion region and the interface. This distance-dependent 30Si self-diffusion was simulated taking into account the effect of Si species generated at the interface upon oxidation and diffusing into SiO2 to enhance Si self-diffusion. The simulation fits the SIMS profiles and these results indicate that Si species, most likely SiO, are emitted from the SiO2/Si interface upon Si thermal oxidation to release the oxidation-induced stress, as has been predicted by recent theoretical studies. Furthermore, combined with our recent results on O self-diffusion, the diffusion behavior of the emitted SiO near the SiO2/Si interface is discussed.