`Triggerless' triggering of vacuum arcs

Anders, André; Brown, Ian; MacGill, R.A.; Dickinson, M.R.

doi:10.1088/0022-3727/31/5/015

Cited by 120 publications

(56 citation statements)

References 16 publications

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“…The cathodes are pulsed using the "triggerless" arc initiation method [13]. The streaming plasma was guided and transported through a curved magnetic macroparticle filter [14] into the magnetic plasma homogenizer [15,16] to deposit highquality films.…”

Section: Methodsmentioning

confidence: 99%

Electrical properties of a-C: Mo films produced by dual-cathode filtered cathodic arc plasma deposition

Sansongsiri

Anders

Yotsombat

2008

Diamond and Related Materials

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Molybdenum-containing amorphous carbon (a-C:Mo) thin films were prepared using a dual-cathode filtered cathodic arc plasma source with a molybdenum and a carbon (graphite) cathode. The Mo content in the films was controlled by varying the deposition pulse ratio of Mo and C. Film sheet resistance was measured in situ at process temperature, which was close to room temperature, as well as ex situ as a function of temperature (300-515 K) in ambient air. Film resistivity and electrical activation energy were derived for different Mo and C ratios and substrate bias. Film thickness was in the range 8-28 nm. Film resistivity varied from 3.55×10 -4 Ω m to 2.27×10 -6 Ω m when the Mo/C pulse ratio was increased from 0.05 to 0.4, with no substrate bias applied. With carbon-selective bias, the film resistivity was in the range of 4.59×10 -2 and 4.05 Ω m at a Mo/C pulse ratio of 0.05.The electrical activation energy decreased from 3.80×10 -2 to 3.36×10 -4 eV when the Mo/C pulse ratio was increased in the absence of bias, and from 0.19 to 0.14 eV for carbonselective bias conditions. The resistivity of the film shifts systematically with the amounts of Mo and upon application of substrate bias voltage. The intensity ratio of the Raman D-peak and G-peak (I D /I G ) correlated with the pre-exponential factor (σ 0 ) which included charge carrier density and density of states.

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Section: Methodsmentioning

confidence: 99%

Electrical properties of a-C: Mo films produced by dual-cathode filtered cathodic arc plasma deposition

Sansongsiri

Anders

Yotsombat

2008

Diamond and Related Materials

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“…In the present study, we have employed open-air N 2 /He DBD plasmas to functionalize the surface of hydrogen-free DLC films. The films were prepared by the filtered cathodic arc which is a well known technique for the deposition of hard carbon DLC films with low hydrogen content [16][17][18]. Surface analysis and characterization after functionalization of the surfaces by DBD were performed using x-ray photoelectron spectroscopy and contact angle measurements.…”

Section: Introductionmentioning

confidence: 99%

Functionalization of hydrogen-free diamond-like carbon films using open-air dielectric barrier discharge atmospheric plasma treatments

Endrino

Marco

Allen

et al. 2008

Applied Surface Science

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A dielectric barrier discharge (DBD) technique has been employed to produce uniform atmospheric plasmas of He and N 2 gas mixtures in open air in order to functionalize the surface of filtered-arc deposited hydrogen-free diamond-like carbon (DLC) films. XPS measurements were carried out on both untreated and He/N 2 DBD plasma treated DLC surfaces. Chemical states of the C 1s and N 1s peaks were collected and used to characterize the surface bonds. Contact angle measurements were also used to record the short-and long-term variations in wettability of treated and untreated DLC.In addition, cell viability tests were performed to determine the influence of various He/N 2 atmospheric plasma treatments on the attachment of osteoblast MC3T3 cells.Current evidence shows the feasibility of atmospheric plasmas in producing long-lasting variations in the surface bonding and surface energy of hydrogen-free DLC and consequently the potential for this technique in the functionalization of DLC coated devices. IntroductionIn a recent study it was shown that the nanoscale wettability of a hydrogenterminated diamond surface was lower than that of regions that had been oxidized using an atomic force microscope tip [1]. The difference in wettability between modified diamond surfaces suggests the application of control wettability of modified carbon surfaces in the fields of medicine and biotechnology, which could also be extended to diamond-like carbon films.Diamond-like carbon (DLC) films are known to be hard, low friction and chemically inert materials. Numerous in-vitro and in-vivo experiments have indicated that DLC can have both excellent biocompatibility and hemocompatibility [2][3][4][5]. In the past, the wettability of DLC coatings has been modified by selective doping using both metal and non-metal dopants [6][7][8]. For instance, both silicon and fluorine can be used to increase the surface energy and reduce the contact angle with water. In one study [6], researchers modified the surface energy of DLC by incorporating oxygen and silicon into the bonding network, thus avoiding the use of harmful fluorine-containing hydrocarbon gases. However, the silicon-containing DLC coatings had 20 times lower wear resistance than undoped DLC films. In other recent study [9], phosphorus-doped DLC films were deposited by applying hybrid plasma immersion ion implantation and deposition (PIIID) techniques; the good wettability exhibited by P-doped DLC samples leads to an increase in hemocompatibility. However, in this study the mechanical properties of the modified films were not analyzed. In a different study [5], substrates with various substrate roughness were employed to investigate the attachment of human osteoblast cells to amorphous carbon films with different surface textures. This study concluded that cell attachment increased monotonically with surface roughness. However, smooth surfaces are critical in the vast majority of biomedical applications and topological functionalization of the surface cannot be seen as a wide-rang...

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“…From the data of Table 1 it is apparent that the 300 V bias resulted in a higher sp 3 content than the 120 V, which is somewhat surprising since it is generally known that carbon ion energies of about 100-200 eV lead to the highest sp 3 content. The formation of diamond bonds is facilitated by densification via energetic condensation, i.e.…”

Section: Figures 6 Indicates That There Is Practically No Difference mentioning

confidence: 92%

“…Repetitively pulsed arc ignition is facilitated by the "triggerless" or "self-trigger" method, i.e. by a current driven between anode and cathode via a conducting coating on the cathode-enclosing ceramic [3].…”

Section: Methodsmentioning

confidence: 99%

Plasma biasing to control the growth conditions of diamond-like carbon

Anders¹,

Pasaja²,

Lim³

et al. 2007

Surface and Coatings Technology

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It is well known that the structure and properties of diamond-like carbon, and in particular the sp /sp ratio, can be controlled by the energy of the condensing carbon ions or atoms. In many practical cases, the energy of ions arriving at the surface of the growing film is determined by the bias applied to the substrate. The bias causes a sheath to form between substrate and plasma in which the potential difference between plasma potential and surface potential drops. In this contribution, we demonstrate that the same results can be obtained with grounded substrates by shifting the plasma potential. This "plasma biasing" (as opposed to "substrate biasing") is shown to work well with pulsed cathodic carbon arcs, resulting in tetrahedral amorphous carbon (ta-C) films that are comparable to the films obtained with the conventional substrate bias. To verify the plasma bias approach, ta-C films were deposited by both conventional and plasma bias and characterized by transmission electron microscopy (TEM) and electron energy loss spectrometry (EELS). Detailed data for comparison of these films are provided.

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`Triggerless' triggering of vacuum arcs

Cited by 120 publications

References 16 publications

Electrical properties of a-C: Mo films produced by dual-cathode filtered cathodic arc plasma deposition

Electrical properties of a-C: Mo films produced by dual-cathode filtered cathodic arc plasma deposition

Functionalization of hydrogen-free diamond-like carbon films using open-air dielectric barrier discharge atmospheric plasma treatments

Plasma biasing to control the growth conditions of diamond-like carbon

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