Stress-driven surface swell and exfoliation of copper as the plasma-facing materials in NBI ICP source

Abstract Neutral beam injection (NBI) heating is a significant auxiliary heating method used in Tokamak fusion devices. The material of faraday shield (FS) and accelerator grids in the NBI inductively coupled plasma (ICP) source can be damaged during operation by the high-density hydrogen plasma irradiation, and thus affecting the stability of the NBI system. In this paper, a series of hydrogen plasma exposure experiments are performed on oxygen-free copper (OFC) specimens at 400-850 K with ion energy of 20-200 eV and irradiation ﬂuence up to 1.0×1025 /m2. Meanwhile, the rate equation model is adopted for numerical simulation of the bubble growth and hydrogen retention. The influence of OFC surface temperature, hydrogen ion energy and fluence on OFC damage are experimentally and numerically investigated. Surface observations show that swell and exfoliation are formed on the OFC samples at 400 K and 600 K by scanning electron microscopy (SEM). The hydrogen ion energy varying from 20 to 200 eV at 400 K is observed to have little effect on OFC surface microstructure. The simulative results show that there exist different critical temperatures when the initial bubble radius changes. The bubble surface density rises and the bubble size decreases with increasing temperature (below the critical temperature). In addition, adjacent bubbles get closer to each other with the growth of hydrogen bubbles, and the strong tensile stress is produced inside the surrounding material of hydrogen bubbles. Some cracks caused by hydrogen bubbles appear on the surface of the OFC to relax the pressure-induced stress, ultimately leading to OFC FS/grids material damage. This investigation helps to understand hydrogen retention and failure mechanisms of OFC materials under extreme operation conditions in the NBI devices.

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Hydrogenation and Defect Creation in GaAs-Based Devices During High Density Plasma Processing

MRS Proceedings ◽

10.1557/proc-510-209 ◽

1998 ◽

Vol 510 ◽

Cited By ~ 1

Author(s):

T. Maeda ◽

J. W. Lee ◽

C. R. Abernathy ◽

S. J. Pearton ◽

F. Ren ◽

...

Keyword(s):

Heterojunction Bipolar Transistors ◽

Inductively Coupled Plasma ◽

Electron Cyclotron Resonance ◽

Field Effect Transistors ◽

High Electron Mobility Transistors ◽

High Electron ◽

Source Power ◽

Ion Energy ◽

Inductively Coupled ◽

Self Bias

AbstractThe effects of Inductively Coupled Plasma (ICP) and Electron Cyclotron Resonance (ECR) H2 plasmas on GaAs metal semiconductor field effect transistors (MESFETs), high electron mobility transistors (HEMTs) and heterojunction bipolar transistors (HBTs) have been measured as a function of ion flux, ion energy and process pressure. The chemical effects of hydrogenation have been compared to direct physical bombardment by Ar plasmas under the same conditions. Si dopant passivation in MESFETs and HEMTs and C base-dopant passivation in HBTs produces much larger changes in sheet resistance, breakdown voltage and device gain or transconductance than Ar ion bombardment and suggests that H2-containing plasma chemistries (CH4/H2 for semiconductor etching, SiH4 for dielectric deposition, CHF3 for dielectric etching) should be avoided, or at least the exposure of the surface minimized. In some cases the device degradation is less for higher source power conditions, due to the suppression of cathode dc self-bias and hence ion energy.

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Real-time feedback control of ion energy flux in chlorine inductively coupled plasma for poly-silicon etch process

IEEE Conference Record - Abstracts 2002 IEEE International Conference on Plasma Science (Cat No 02CH37340) PLASMA-02 ◽

10.1109/plasma.2002.1030590 ◽

2003 ◽

Author(s):

C.H. Chang ◽

K.C. Leou ◽

C. Lin ◽

T.L. Lin ◽

C.W. Tseng ◽

...

Keyword(s):

Feedback Control ◽

Real Time ◽

Energy Flux ◽

Inductively Coupled Plasma ◽

Ion Energy ◽

Inductively Coupled ◽

Poly Silicon

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Plasma-Assisted Nitriding in Low-Frequency Inductively Coupled Plasma Enhanced with Ferromagnetic Cores

High Temperature Materials and Processes ◽

10.1515/htmp-2016-0233 ◽

2018 ◽

Vol 37 (6) ◽

pp. 545-550

Author(s):

Mikhail Isupov ◽

Vadim Pinaev ◽

Daria Mul ◽

Natalia Belousova

Keyword(s):

Inductively Coupled Plasma ◽

High Speed ◽

Low Frequency ◽

Sample Surface ◽

Ion Energy ◽

Inductively Coupled ◽

Steel Aisi ◽

Current Densities ◽

Aisi 321 ◽

Stainless Steel Aisi

AbstractAn experimental investigation of plasma-assisted nitriding of austenitic stainless steel AISI 321 in a low-pressure (7 Pa), low-frequency (50–100 kHz) nitrogen inductively coupled plasma enhanced with ferromagnetic cores has been performed at the temperatures of 470–625 °C, sample biases of ‒500–‒750 V, current densities on the sample surface of 1.2–3.3 mA/cm2 and nitriding times of 20 and 60 min. It is found that even the short (20 min) ion-plasma treatment results in the formation of nitrided layers with the thickness of up to 40 μm and microhardness of up to 9 GPa.The high speed of nitriding can be explained as a result of the joint action of high ion flux density and high ion energy on the sample surface.

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Low Bias Dry Etching of Sic and Sicn in ICP NF3 Discharges

MRS Proceedings ◽

10.1557/proc-512-507 ◽

1998 ◽

Vol 512 ◽

Author(s):

J. J. Wang ◽

Hyun Cho ◽

E. S. Lambers ◽

S. J. Peartont ◽

M. Ostling ◽

...

Keyword(s):

Inductively Coupled Plasma ◽

Ion Flux ◽

Pattern Transfer ◽

Plasma Composition ◽

Source Power ◽

Ion Energy ◽

Trade Off ◽

Inductively Coupled ◽

Extensive Surface ◽

Etch Rates

ABSTRACTA parametric study of the etching characteristics of 6H p+ and n+ SiC and thin film SiC0.8N0.2 in Inductively Coupled Plasma NF3/O2 and NF3/Ar discharges has been performed. The etch rates in both chemistries increase monotonically with NF3 percentage and rf chuck power reaching 3500Å·min−1 for SiC and 7500 Å·min−1 for SiCN. The etch rates go through a maximum with increasing ICP source power, which is explained by a trade-off between the increasing ion flux and the decreasing ion energy. The anisotropy of the etched features is also a function of ion flux, ion energy and atomic fluorine neutral concentration. Indium-tinoxide( ITO) masks display relatively good etch selectivity over SiC(maximum of 70:1) while photoresist etches more rapidly than SiC. The surface roughness of SiC is essentially independent of plasma composition for NF3/O2 discharges, while extensive surface degradation occurs for SiCN under high NF3:O2 conditions. The high ion flux available in the ICP tool allows etching even at very low dc self-biases, ≤ −10V, leading to very low damage pattern transfer.

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New Bactericide Orthodonthic Archwire: NiTi with Silver Nanoparticles

Metals ◽

10.3390/met10060702 ◽

2020 ◽

Vol 10 (6) ◽

pp. 702

Author(s):

F. Javier Gil ◽

Eduardo Espinar-Escalona ◽

Nuria Clusellas ◽

Javier Fernandez-Bozal ◽

Montserrat Artes-Ribas ◽

...

Keyword(s):

Silver Nanoparticles ◽

Martensitic Transformation ◽

Inductively Coupled Plasma ◽

Artificial Saliva ◽

Bacterial Strains ◽

Ion Release ◽

Critical Temperatures ◽

Nickel Ion ◽

Bacteria Culture ◽

Nanoparticles Of Silver

A potential new bactericide treatment for NiTi orthodontic archwires based in the electrodeposition of silver nanoparticles on the surface was studied. Twenty-five archwires were treated by electrodeposition, obtaining nanoparticles of silver embedded on the archwire surface. These were evaluated in order to investigate the possible changes on the superelastic characteristics (critical temperatures and stresses), the nickel ion release, and the bacteria culture behavior. The chemical composition was analyzed by Energy Dispersive X-Ray Spectroscopy-microanalysis; the singular temperatures of the martensitic transformation were obtained by a flow calorimeter. Induced martensitic transformation stresses were obtained by mechanical testing apparatus. Nickel ion release was analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) equipment using artificial saliva solution at 37 °C. Bacterial tests were studied with the most used oral bacterial strains: Streptococcus sanguinis and Lactobacillus salivarius. NiTi samples were immersed in bacterial suspensions for 2 h at 37 °C. Adhered bacteria were separated and seeded on agar plates: Tood-Hewitt (TH) and Man-Rogosa-Sharpe (MRS) for S. sanguinis and for L.salivarius, respectively. These were then incubated at 37 °C for 1 day and the colonies were analyzed. The results showed that the transformation temperatures and the critical stresses have not statistically significant differences. Likewise, nickel ion release at different immersion times in saliva at 37 °C does not present changes between the original and treated with silver nanoparticles archwires. Bacteria culture results showed that the reduction of the bacteria due to the presence to the nanoparticles of silver is higher than 90%. Consequently, the new treatment with nanoparticles of silver could be a good candidate as bactericidic orthodontic archwire.

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Investigation of Low-Temperature Hydrogen Plasma-Etching Processes for Silicon Wafer Solar Cell Surface Passivation in an Industrial Inductively Coupled Plasma Deposition Tool

IEEE Journal of Photovoltaics ◽

10.1109/jphotov.2015.2481607 ◽

2016 ◽

Vol 6 (1) ◽

pp. 10-16 ◽

Cited By ~ 4

Author(s):

Muzhi Tang ◽

Jia Ge ◽

Johnson Wong ◽

Zhe Liu ◽

Torsten Dippell ◽

...

Keyword(s):

Solar Cell ◽

Low Temperature ◽

Cell Surface ◽

Silicon Wafer ◽

Plasma Etching ◽

Inductively Coupled Plasma ◽

Surface Passivation ◽

Plasma Deposition ◽

Hydrogen Plasma ◽

Inductively Coupled

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Bubble dynamics in a compressible liquid in contact with a rigid boundary

Interface Focus ◽

10.1098/rsfs.2015.0048 ◽

2015 ◽

Vol 5 (5) ◽

pp. 20150048 ◽

Cited By ~ 20

Author(s):

Qianxi Wang ◽

Wenke Liu ◽

A. M. Zhang ◽

Yi Sui

Keyword(s):

Shock Waves ◽

Thin Layer ◽

High Speed ◽

Bubble Radius ◽

Time History ◽

Bubble Surface ◽

Boundary Integral ◽

Boundary Integral Method ◽

Imaging Method ◽

Rigid Boundary

A bubble initiated near a rigid boundary may be almost in contact with the boundary because of its expansion and migration to the boundary, where a thin layer of water forms between the bubble and the boundary thereafter. This phenomenon is modelled using the weakly compressible theory coupled with the boundary integral method. The wall effects are modelled using the imaging method. The numerical instabilities caused by the near contact of the bubble surface with the boundary are handled by removing a thin layer of water between them and joining the bubble surface with its image to the boundary. Our computations correlate well with experiments for both the first and second cycles of oscillation. The time history of the energy of a bubble system follows a step function, reducing rapidly and significantly because of emission of shock waves at inception of a bubble and at the end of collapse but remaining approximately constant for the rest of the time. The bubble starts being in near contact with the boundary during the first cycle of oscillation when the dimensionless stand-off distance γ = s / R m < 1, where s is the distance of the initial bubble centre from the boundary and R m is the maximum bubble radius. This leads to (i) the direct impact of a high-speed liquid jet on the boundary once it penetrates through the bubble, (ii) the direct contact of the bubble at high temperature and high pressure with the boundary, and (iii) the direct impingement of shock waves on the boundary once emitted. These phenomena have clear potential to damage the boundary, which are believed to be part of the mechanisms of cavitation damage.

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