Energetics of vacuum arc cathode spots

Anders, André

doi:10.1063/1.1370541

Cited by 22 publications

(16 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The average data for quasi-steady-state conditions (t > 150 µs) are also included in Table 1. As anticipated from energy considerations 20 and detected in previous data 25 , the arc burning voltage and the kinetic energy are correlated as shown in figure 4.…”

Section: A Ion Flux Measurements Without External Magnetic Fieldsupporting

confidence: 56%

“…The arc current, as given by the circuit, and the self-adjusting burning voltage determine the energy input and the characteristic plasma parameters. As was experimentally shown 19 , the material specific burning voltage has a surprisingly simple, linear relation to the cohesive energy of the cathode material ("Cohesive Energy Rule" 20 ). In this paper we expand the research on ion velocities and other ion flux parameters to address the following issues:…”

mentioning

confidence: 99%

See 1 more Smart Citation

Ion flux from vacuum arc cathode spots in the absence and presence of a magnetic field

Anders

Yushkov

2002

Journal of Applied Physics

Self Cite

348

155

View full text Add to dashboard Cite

Because plasma production at vacuum cathode spots is approximately proportional to the arc current, arc current modulation can be used to generate ion current modulation that can be detected far from the spot using a negatively biased ion collector. The drift time to the ion detector can used to determine kinetic ion energies. A very wide range of cathode materials have been used. It has been found that the kinetic ion energy is higher at the beginning of each discharge and approximately constant after 150 µs. The kinetic energy is correlated with the arc voltage and the cohesive energy of the cathode material. The ion erosion rate has in inverse relation to the cohesive energy, enhancing the effect that the power input per plasma particle correlates with the cohesive energy of the cathode material. The influence of three magnetic field configurations on the kinetic energy has been investigated. Generally, a magnetic field increases the plasma impedance, arc burning voltage, and kinetic ion energy. However, if the plasma is produced in a region of low field strength and streaming into a region of higher field strength, the velocity may decrease due to the mirror effect. A magnetic field can increase the plasma temperature but may reduce the density gradients by preventing free expansion into vacuum. Therefore, depending on the configuration, a magnetic field may increase or decrease the kinetic energy of ions. Additionally, the angular distribution of the ion flux and ion kinetic energy has been investigated in the absence of an external magnetic field. The result can be fitted by a superposition of an isotropic and a cosine distribution. * Corresponding Author, aanders@lbl.gov 3

show abstract

Section: A Ion Flux Measurements Without External Magnetic Fieldsupporting

confidence: 56%

mentioning

confidence: 99%

Ion flux from vacuum arc cathode spots in the absence and presence of a magnetic field

Anders

Yushkov

2002

Journal of Applied Physics

Self Cite

348

155

View full text Add to dashboard Cite

show abstract

“…At that time, they argued that the high initial voltage in the first ≈25 μs (compare to figure 3(b)) and current fluctuations cannot solely explain the observed changes in charge states. Current fluctuations can have a minor effect on charge states [33,34], due to changes in the electrical power input related to electron temperatures in the plasma [35] and thereby to the observed charge states. Such effects might also affect the present results, because of the not precisely 'rectangular' current pulse shape and fluctuations in power (see figure 3(a)).…”

Section: Ion Charge State Distributionsmentioning

confidence: 99%

Time-resolved ion energy and charge state distributions in pulsed cathodic arc plasmas of Nb−Al cathodes in high vacuum

Zöhrer

Anders

Franz

2018

Plasma Sources Sci. Technol.

Self Cite

View full text Add to dashboard Cite

Cathodic arcs have been utilized in various applications including the deposition of thin films and coatings, ion implantation, and high current switching. Despite substantial progress in recent decades, the physical mechanisms responsible for the observed plasma properties are still a matter of dispute, particularly for multi-element cathodes, which can play an essential role in applications. The analysis of plasma properties is complicated by the generally occurring neutral background of metal atoms, which perturbs initial ion properties. By using a time-resolved method in combination with pulsed arcs and a comprehensive Nb−Al cathode model system, we investigate the influence of cathode composition on the plasma, while making the influence of neutrals visible for the observed time frame. The results visualize ion detections of 600 μs plasma pulses, extracted 0.27 m from the cathode, resolved in mass-per-charge, energy-per-charge and time. Ion properties are found to be strongly dependent on the cathode material in a way that cannot be deduced by simple linear extrapolation. Subsequently, current hypotheses in cathodic arc physics applying to multi-element cathodes, like the so-called 'velocity rule' or the 'cohesive energy rule', are tested for early and late stages of the pulse. Apart from their fundamental character, the findings could be useful in optimizing or designing plasma properties for applications, by actively utilizing effects on ion distributions caused by composite cathode materials and charge exchange with neutrals.

show abstract

“…To increase the ionization state and to reduce the thermal load on cathode and substrate several groups developed and used the pulsed vacuum arc [4]. Very recently much progress has been made in understanding the nature of the cathode spot, the distribution of energy ions, the role of cohesive energy [5], the importance of atomic scale heating [6] and selfsputtering [7]. However oxygen and hydrogen incorporation in films produced in the pulsed mode [8,9] and in DC operation [10] is also often reported.…”

Section: Introductionmentioning

confidence: 99%

UHV arc for high quality film deposition

Russo

Cianchi²,

Akhmadeev

et al. 2006

Surface and Coatings Technology

View full text Add to dashboard Cite

The vacuum arc is a well-known technique for producing coatings with enhanced adhesion and film density. Many cathodic arc deposition systems are actually in use in industry and research. They all work under (high) vacuum conditions in which water vapour pressure is an important source of film contamination, especially in the pulsed arc mode of operation. Here we present a cathodic arc system working under ultra-high vacuum conditions (UHVCA). We have used for arc ignition a Nd-YAG pulsed laser focused on the cathode surface, which provides a reliable system and allows eliminating all possible sources of contaminants. We have proven that the arc technique produces bulk-like films suitable for superconducting applications. UHVCA has been used to produce ultra-pure niobium films with excellent structural and electrical properties at a deposition temperature lower than 100oC. The UHVCA technique therefore opens up new perspectives for all applications requiring pure films and low deposition temperatures.

show abstract

Energetics of vacuum arc cathode spots

Cited by 22 publications

References 9 publications

Ion flux from vacuum arc cathode spots in the absence and presence of a magnetic field

Ion flux from vacuum arc cathode spots in the absence and presence of a magnetic field

Time-resolved ion energy and charge state distributions in pulsed cathodic arc plasmas of Nb−Al cathodes in high vacuum

UHV arc for high quality film deposition

Contact Info

Product

Resources

About