Influence of Oxygen Concentration of Si Wafer Surface in Si Emission on Nano Ordered Three-Dimensional Structure Devices

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The mechanism of Si pillar thermal oxidation is considered. The Si emission is discussed in the oxidation of three-dimensional structures, which must be fundamentally important to understand the oxidation mechanism. It is confirmed that the Si emission is enhanced in the three-dimensional structures by the geometrical and stress effects. The larger effect is expected for Si spheres rather than for Si pillars. More enhanced Si emission can be expected for the smaller spheres. Then the mechanism of Si missing and the effect of Si emission are also discussed. The oxide viscous flow mechanism is the promising candidate to explain the Si missing, because the oxide viscosity could be reduced by the SiO incorporation and the compressive stress. The geometrical effect induces the viscosity gradient, which is important to induce the Si missing. Interplay of the emitted SiO and the accumulated stress is the key in Si pillar oxidation. Careful approaches are suggested for the oxidation of three-dimensional structures.

Section: Si Missing Mechanismsupporting

confidence: 51%

“…[5][6][7][8][9] We also observe quite similar phenomena experimentally. 10,11) These unique phenomena for the oxidation of 3D structures are thought to come from several reasons. In silicon oxidation, it is known that Si is emitted from the interface into the oxide as well as into the silicon substrate.…”

Section: Introductionmentioning

confidence: 99%

Reconsideration of Si pillar thermal oxidation mechanism

Kageshima¹,

Shiraishi²,

Endoh³

2018

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“…It is also known that Si missing and self-limiting occur during the oxidation process of nanopillars. 72,73) The oxidized pillars have thinner diameters than those expected from simple conversion from Si into SiO 2 . The oxidation stops after a while and shows selflimitation.…”

Section: Introductionmentioning

confidence: 99%

First-principles study of pressure and SiO-incorporation effect on dynamical properties of silicon oxide

Kageshima¹,

Yajima²,

Shiraishi³

et al. 2019

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The pressure and SiO-incorporation effect on the temperature dependence of dynamical properties for silicon oxide (SiO2)1−x(SiO)x is theoretically studied by first-principles molecular dynamics. It is found that the incorporation of SiO enhances the selfdiffusions even under high pressure. The SiO effect on Si selfdiffusion is however reduced by the pressure at temperature lower than 4000 K, and the amount of reduction is larger for lower temperature, while the effect on O selfdiffusion is hardly reduced, being independent of the temperature. Such a difference is thought to come from the difference in selfdiffusion mechanisms between Si and O. It is indicated that the incorporated SiO acts as combined SiO interstitials rather than separate Si interstitials or O vacancies. This also suggests that the oxide viscous flow mechanism is a promising candidate for the origin of the Si missing in oxidizing Si nanopillars.

“…It is known that such strain leads to the unconventional growth of Si oxide film. 4,5) The strain induced in the oxide film could also have an unconventional effect on the film reliability such as dielectric breakdown. Previous studies have reported that the dielectric breakdown of the oxide film is triggered by O-vacancy (V O )-related defects in the film.…”

Section: Introductionmentioning

confidence: 99%

First-principles study of strain effect on oxygen vacancy in silicon oxide

Yata¹,

Kageshima²

2021

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The strain dependence of stability and diffusion barrier height of the O vacancy in Si oxide is examined using the first-principles calculation. It is found that the stability and the diffusion barrier height increase as the oxide is compressed. The analysis shows that the diffusion barrier height is determined by the Si–Si distance of the O vacancy. Based on these results, the dielectric breakdown of the gate Si oxide film in the three-dimensional structure metal-oxide-semiconductor field-effect transistor is also considered. It is suggested that the interfacial O-vacancy density increases because the interfacial oxide is subjected to compressive strain. On the other hand, the surface O-vacancy density decreases and the surface O-vacancy diffusion is promoted because the surface oxide is subjected to tensile strain. The reliability of the oxide film might be thus affected by the strain.