Study on silicon removal property and surface smoothing phenomenon by moderate-pressure microwave hydrogen plasma

Ohmi, Hiromasa; Kimoto, Kenta; Nomura, Toshimitsu; Kakiuchi, Hiroaki; Yasutake, Kiyoshi

doi:10.1016/j.mssp.2021.105780

Cited by 6 publications

(4 citation statements)

References 48 publications

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“…1D), the H plasma, from glow discharge under the action of a strong electric field, reacts with O on the surface of the FeNb 11 O 29 -Piece crystal to produce volatile gas H 2 O, thus generating abundant oxygen vacancies in its crystal. 31,32 As a result, the prepared FeNb 11 O 29− x @C demonstrates a large specific surface area, more active site points, and a good edge effect, which is helpful to strengthen the Li + reactivity and OER kinetics. Meanwhile, the oxygen vacancies, from H 2 plasma etching, increase the electron density of the adjacent metal atoms, which can enhance the FeNb 11 O 29− x @C electrical conductivity, Li + transport rate and OER charge transfer.…”

Section: Resultsmentioning

confidence: 98%

“…There are two reasons for the formation of lattice defects: (1) the oxygen vacancies generated from H 2 plasma etching can destroy part of the lattice, resulting in lattice defects. 31 (2) Multiple heat treatments at high temperatures produce lattice defects. 37 In general, lattice defects can provide more active sites, thus boosting the Li + storage capacity and OER catalytic activity.…”

Section: Resultsmentioning

confidence: 99%

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Porous biscuit-like nanoplate FeNb₁₁O_29−x@C for lithium-ion storage and oxygen evolution

Lian

Bai

et al. 2022

Nanoscale

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Porous biscuit-like nanoplate FeNb₁₁O_29−x@C for lithium-ion storage and oxygen evolution

Lian

Bai

et al. 2022

Nanoscale

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“…The pressure was fixed to 3.3 kPa during the plasma etching treatment. This pressure value was selected because a relatively high-rate Si etching was achieved in the previous study [15].…”

Section: Methodsmentioning

confidence: 99%

“…Recently, we developed an Si etching process using relatively high-pressure (several kilopascals) H 2 plasma generated in a narrow gap of 0.5 mm [15]. This H 2 plasma achieved high etching rates (>6.5 × 10 3 nm min −1 ) of Si-based samples.…”

Section: Introductionmentioning

confidence: 99%

High-rate etching of silicon oxide and nitride using narrow-gap high-pressure (3.3 kPa) hydrogen plasma

Nomura,

Kakiuchi,

Ohmi

2024

J. Phys. D: Appl. Phys.

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We investigated the etching behavior of silicon oxide (SiOx) and silicon nitride (SiNx) in narrow-gap, high-pressure (3.3 kPa) hydrogen (H2) plasma under various etching conditions. Maximum etching rates of 940 and 240 nm/min for SiOx and SiNx, respectively, were obtained by optimizing the H2 gas flow rate. The dependence of the etching rate on gas flow rate implied that effective elimination of etching products is important for achieving high etching rates because it prevents redeposition. The sample surfaces, especially the oxide surfaces, were roughened and contained numerous asperities after etching. Etching rates of both SiOx and SiNx decreased as the temperature was raised. This suggests that atomic H adsorption, rather than H-ion bombardment, is an important step in the etching process. X-ray photoelectron spectroscopy revealed that the etched nitride surface was enriched in silicon (Si), suggesting that the rate-limiting process in high-pressure H2 plasma etching is Si etching rather than nitrogen abstraction. The etching rate of SiOx was three times higher than that of SiNx despite the higher stability of Si–O bonds than Si–N ones. One reason for the etching difference may be the difference between the bond densities of SiOx and SiNx. This study presents a relatively non-toxic, low-cost, and eco-friendly dry etching process for Si-based dielectrics using only H2 gas in comparison with the conventional F-based plasma etching methods.

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Diffusion of excessively adsorbed hydrogen atoms on hydrogen terminated Si(100)(2×1) surface

et al. 2021

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The diffusion properties of an excess H atom adsorbed on a fully H-terminated Si(100)(2 × 1)-H surface have been analyzed by means of density functional theory-generalized gradient approximation calculations. Our diffusion pathway models consist of sequences of hops between metastable Si surface atomic structures with an excess H atom. We analyzed the reaction path and corresponding barrier height in each hop using the climbing image nudged elastic band method. The activation energies for diffusion along intra-dimer, intra-row, and inter-row pathways are found to be 0.11, 0.54, and 0.74 eV, respectively, which are quite small compared to the common H diffusion running with a vacant site of hydrogen termination. The weak adsorption energy of the excess H atom is responsible for the small activation energy of diffusion. The present diffusion mechanism suggests that the physical substance of the “hot atom mechanism” proposed in the previous investigations on H exposure onto the Si surface is related to the metastable structures of excessively adsorbed hydrogen atoms.

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Study on silicon removal property and surface smoothing phenomenon by moderate-pressure microwave hydrogen plasma

Cited by 6 publications

References 48 publications

Porous biscuit-like nanoplate FeNb₁₁O_29−x@C for lithium-ion storage and oxygen evolution

Porous biscuit-like nanoplate FeNb₁₁O_29−x@C for lithium-ion storage and oxygen evolution

High-rate etching of silicon oxide and nitride using narrow-gap high-pressure (3.3 kPa) hydrogen plasma

Diffusion of excessively adsorbed hydrogen atoms on hydrogen terminated Si(100)(2×1) surface

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Study on silicon removal property and surface smoothing phenomenon by moderate-pressure microwave hydrogen plasma

Cited by 6 publications

References 48 publications

Porous biscuit-like nanoplate FeNb11O29−x@C for lithium-ion storage and oxygen evolution

Porous biscuit-like nanoplate FeNb11O29−x@C for lithium-ion storage and oxygen evolution

High-rate etching of silicon oxide and nitride using narrow-gap high-pressure (3.3 kPa) hydrogen plasma

Diffusion of excessively adsorbed hydrogen atoms on hydrogen terminated Si(100)(2×1) surface

Contact Info

Product

Resources

About

Porous biscuit-like nanoplate FeNb₁₁O_29−x@C for lithium-ion storage and oxygen evolution

Porous biscuit-like nanoplate FeNb₁₁O_29−x@C for lithium-ion storage and oxygen evolution