Hydrogen plasma etching of diamond films deposited on graphite

Villalpando, Isaela; Porro, Samuele; Wilson, J.I.B.

doi:10.1016/j.diamond.2011.03.007

Cited by 37 publications

(19 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…it was shown that exposing BDD samples to hydrogen plasma at high surface temperature results in a reduction of sp2 content (see also Figure 3(a) of the present paper) due to a preferential etching of sp2 phases 74 . As seen in Figure 3(d), the NCD surface behaves in a similar fashion.…”

Section: D) Discussionsupporting

confidence: 63%

Negative-ion production on carbon materials in hydrogen plasma: influence of the carbon hybridization state and the hydrogen content on H⁻yield

Ahmad¹,

Pardanaud²,

Carrère³

et al. 2014

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Highly oriented poly crystalline graphite (HOPG), boron-doped diamond (BDD), nanocrystalline diamond (NCD), ultra-nano-crystalline diamond (uNCD), fullerenes C60 and C70 and Diamond Like Carbon (DLC) surfaces are exposed to low pressure hydrogen plasma in a 13.56 MHz plasma reactor. Relative yields of surface produced Hions due to bombardment of positive ions from the plasma are measured by an energy analyzer cum quadrupole mass spectrometer. Irrespective of plasma conditions (0.2 and 2 Pa), HOPG surfaces show the highest yield at room temperature (RT), while at high temperature (HT), the highest yield (~ 5 times compared to HOPG surface at room temperature) is observed on BDD surfaces. The shapes of ion distribution functions (IDFs) are compared at RT and HT to demonstrate the mechanism of ion generation at the surface. Raman spectroscopy analyses of the plasma exposed samples reveal surface modifications influencing Hproduction yields, while further analyses strongly suggest that the hydrogen content of the material and the sp3/sp2 ratio are the key parameters in driving surface ionization efficiency of carbon materials under the chosen plasma conditions.

show abstract

Section: D) Discussionsupporting

confidence: 63%

Negative-ion production on carbon materials in hydrogen plasma: influence of the carbon hybridization state and the hydrogen content on H⁻yield

Ahmad¹,

Pardanaud²,

Carrère³

et al. 2014

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…Defects/non diamond phases produced by plasma exposure are annealed and etched away by the plasma at high temperature. Enhanced sp 2 phases etching at high temperature has indeed already been observed [92,93]. Therefore when increasing the temperature, the diamond surface is reconstructed and the surface state under plasma exposure is probably closer to the pristine material than it would be at room temperature.…”

Section: Diamond As Negative-ion High Yield Material: Results and Dismentioning

confidence: 72%

Alternative solutions to caesium in negative-ion sources: a study of negative-ion surface production on diamond in H₂/D₂ plasmas

et al. 2017

View full text Add to dashboard Cite

This paper deals with a study of H − /D − negative ion surface production on diamond in low pressure H 2 /D 2 plasmas. A sample placed in the plasma is negatively biased with respect to plasma potential. Upon positive ion impacts on the sample, some negative ions are formed and detected according to their mass and energy by a mass spectrometer placed in front of the sample. The experimental methods developed to study negative ion surface production and obtain negative ion energy and angle distribution functions are first presented. Different diamond materials ranging from nanocrystalline to single crystal layers, either doped with boron or intrinsic, are then investigated and compared with graphite. The negative ion yields obtained are presented as a function of different experimental parameters such as the exposure time, the sample bias which determines the positive ion impact energy and the sample surface temperature. It is concluded from these experiments that the electronic properties of diamond materials, among them the negative electron affinity, seem to be favourable for negative-ion surface production. However, the negative ion yield decreases with the plasma induced defect density. fusion power-plant prototype producing electrical energy, targeting ∼1 GW of electrical power coupled to the grid [23,24]. In the ITER and DEMO devices, the heating of the plasma will mainly be produced by neutral beam injection (NBI). NBIs systems are key components in achieving high fusion energetic-performances. The ITER NBIs are required to inject 1 MeV beams of neutral deuterium atoms (D) into the tokamak, providing plasma heating and current drive. At such high velocities, much larger than classical electron orbit velocities of hydrogen atoms, the probability of electron capture from D + ions is too low, so that production of D relies on electron detachment from high-intensity D − beams. D − negative-ions are produced in a low-pressure plasma source and subsequently extracted and accelerated.The ITER negative ion source, currently under development at IPP Garching [7,25] in Germany, operates with a high-density, low-pressure inductively coupled plasma. Extracted D − current density of 200 A m −2 , over a large surface of 1.2 m 2 , with 5%-10% uniformity and low co-extracted electron-current (below one electron per negative ion), during long operation period (3600 s) is targeted. To reach such a high D − negative-ion current, the only up-to-date scientific solution is the use of caesium. Deuterium negative-ions are created at the extraction region by backscattering of positive ions or neutrals on the plasma grid. Deposition of caesium on the grid lowers the material work function and allows for high electron-capture efficiency by incident particles and thus, high negative ion yields. Studies conducted at IPP Garching show that the ITER negative-ion source can reach the required high current densities. However, drawbacks to the use of caesium have been identified. First, the caesium is continuously injected in the source a...

show abstract

“…because sp and sp2 carbon reacts with hydrogen radicals and ions more readily than does sp3 bound carbon [28]. In addition to PECVD photo-dissociation of hydrogen molecules under pinch radiation should be taken into account.…”

Section: Discussionmentioning

confidence: 99%

Characterization of carbon contamination under ion and hot atom bombardment in a tin-plasma extreme ultraviolet light source

Dolgov

Lopaev

Lee

et al. 2015

Applied Surface Science

142

View full text Add to dashboard Cite

Molecular contamination of a grazing incidence collector for extreme ultraviolet (EUV) lithography was experimentally studied. A carbon film was found to have grown under irradiation from a pulsed tin plasma discharge. Our studies show that the film is chemically inert and has characteristics that are typical for a hydrogenated amorphous carbon film. It was experimentally observed that the film consists of carbon (~70 at. %), oxygen (~20 at. %) and hydrogen (bound to oxygen and carbon), along with a few at. % of tin. Most of the oxygen and hydrogen are most likely present as OH groups, chemically bound to carbon, indicating an important role for adsorbed water during the film formation process. It was observed that the film is predominantly sp3 hybridized carbon, as is typical for diamond-like carbon. The Raman spectra of the film, under 514 and 264 nm excitation, are typical for hydrogenated diamond-like carbon. Additionally, the lower etch rate and higher energy threshold in chemical ion sputtering in H 2 plasma, compared to magnetron-sputtered carbon films, suggests that the film exhibits diamond-like carbon properties.

show abstract

Hydrogen plasma etching of diamond films deposited on graphite

Cited by 37 publications

References 19 publications

Negative-ion production on carbon materials in hydrogen plasma: influence of the carbon hybridization state and the hydrogen content on H⁻yield

Negative-ion production on carbon materials in hydrogen plasma: influence of the carbon hybridization state and the hydrogen content on H⁻yield

Alternative solutions to caesium in negative-ion sources: a study of negative-ion surface production on diamond in H₂/D₂ plasmas

Characterization of carbon contamination under ion and hot atom bombardment in a tin-plasma extreme ultraviolet light source

Contact Info

Product

Resources

About

Hydrogen plasma etching of diamond films deposited on graphite

Cited by 37 publications

References 19 publications

Negative-ion production on carbon materials in hydrogen plasma: influence of the carbon hybridization state and the hydrogen content on H−yield

Negative-ion production on carbon materials in hydrogen plasma: influence of the carbon hybridization state and the hydrogen content on H−yield

Alternative solutions to caesium in negative-ion sources: a study of negative-ion surface production on diamond in H2/D2 plasmas

Characterization of carbon contamination under ion and hot atom bombardment in a tin-plasma extreme ultraviolet light source

Contact Info

Product

Resources

About

Negative-ion production on carbon materials in hydrogen plasma: influence of the carbon hybridization state and the hydrogen content on H⁻yield

Negative-ion production on carbon materials in hydrogen plasma: influence of the carbon hybridization state and the hydrogen content on H⁻yield

Alternative solutions to caesium in negative-ion sources: a study of negative-ion surface production on diamond in H₂/D₂ plasmas