Observation and lifetime of autoionising states of Ar produced in a glow discharge ion source

Mason, Rod S.; Anderson, Peter D. J.; Fernandez, M. Tereza

doi:10.1016/0168-1176(93)87019-o

Cited by 7 publications

(2 citation statements)

References 10 publications

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“…Many studies have proven that when more than one element was present in the sputtering target, a content bias was observed in the coating [24]. Table 3 shows the sputtering data of Ni and Cr under the 100 eV argon ion bombardment [25,26]. This indicates a small difference of sputtering rate between Cr and Ni, resulting in a content bias between the coating and sputtering target.…”

Section: Resultsmentioning

confidence: 99%

Oxidation behaviour of plasma surface alloying on Ti6Al4V alloy

Wei

Zhang

Yao

et al. 2018

Surface Engineering

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Ti-CrNi alloy coatings with 20, 40, 60 and 80 at-%Ni were prepared on Ti6Al4V alloy surface by double glow plasma surface alloying technique. The cyclic oxidation behaviour of the coatings was investigated at 750, 850 and 950°C. The results show that each coating has a complete structure of settled layer, mutual diffusion layer and sputtering affected zone. When the Ni content was 40 at-%, the Ti-CrNi alloy coating showed the best cyclic oxidation resistance. The oxide scale with 'Cr 2 O 3 film+NiO film' structure showed the best resistance to peeling.

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Section: Resultsmentioning

confidence: 99%

Oxidation behaviour of plasma surface alloying on Ti6Al4V alloy

Wei

Zhang

Yao

et al. 2018

Surface Engineering

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“…Even so, as discussed above, it is widely believed that chemi-ionisation is responsible for the bulk of cathode ion signals detected, usually assigned to Penning ionisation by the reaction with argon metastables, Ar(4s, 3 P). However, evidence of long-lived Ar Rydberg atoms has been reported 36 emerging even from these types of source. Furthermore, in our recent FFGD studies of the H 2 effect, 12 a Rydberg gas and ''cascade'' mechanism of cathode atom excitation and ionisation was found to fit well with all the experimental evidence obtained.…”

Section: Comparison With Other Gd Sourcesmentioning

confidence: 99%

Ion formation at the boundary between a fast flow glow discharge ion source and a quadrupole mass spectrometer

Mason

Williams

Mortimer

et al. 2004

J. Anal. At. Spectrom.

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An ion source is described for use in low power glow discharge mass spectrometry, using fast flowing argon as the discharge gas, and attached to a quadrupole analyser. The flow carries the plasma downstream onto an ion exit sampling cone which can be variably biased relative to the anode, enabling the physical and chemical properties of the plasma to be studied independently of the main ionisation region, the cathode fall. The parts of the plasma studied were characterised by fixed probe potential measurements. Cone bias effects are consistent with a plasma which contains large quantities of high n Rydberg atoms of both the discharge gas and the sputtered cathode. The ionisable atom flux passing through the sampling aperture was measured directly, giving densities inside the plasma of 10 10 -10 11 cm 23 . The densities of lower n Rydbergs are expected to be very much higher. H 2 is shown to quench these states and promote excitation of the cathode atoms to their Rydberg states. Field-ionisation or Auger deexcitation of the Rydberg gas inside the cell gives a high intensity cathode ion beam, which is relatively uncontaminated by the higher ionisation potential species, such as are formed from the discharge gas.

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Cathodic bombardment and sputtering in the 0.5–4.0 torr pressure region of a glow‐discharge ion source

Mason

Milton

Pichilingi

et al. 1994

Rapid Comm Mass Spectrometry

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Cathodic ion sputtering energies have been studied in a glow-discharge ion source, operated in the ranges 0.5-2.0 Torr pressure and 100-1000 V discharge voltage using ion kinetic energy spectroscopy. Average energies in the range 10-20 eV were measured. These energies are very low compared with the theoretical prediction of the charge-transfer model. In view of this, the high sputtering yields measured are surprising. It is inferred that the sputtering is caused, not by the discharge gas ions as is still widely believed, but by fast discharge-gas atoms. A means of estimating the average energy of the neutral flux is found by comparing presently measured thresholds with Literature values directly obtained. The average energy seems to be about three times greater than that of the ions. The neutral flux is crudely estimated by comparison of the apparent nett sputter yields measured here with tabulated primary values and taking into account back-diffusion. It is found to be > 100 times larger than the ion flux. The flux created by charge transfer alone is therefore not enough to explain the high sputtering yields measured. Higher energy ions detected and composed mainly of ionized cathodic atoms appear to be formed in a region intermediate between the negative glow and the cathode, which again is different from the generally held view.Glow-discharge mass spectrometry (GDMS) has become an important technique €or the analysis of trace components in metals and semiconductor materials.',' Essentially, the GD consists of two electrodes in a gas with a sufficiently high voltage applied across them to maintain a continuous electrical discharge. In GDMS, the sample forms the cathode. The sputtered atoms of the sample are launched into the gas phase where they become ionized. These ions are sampled through an orifice in the anode and analysed by mass spectrometry.that the sputtering is caused by surface bombardment of the cathode, mainly involving cations of the discharge gas, accelerated from the negative glow (see Fig. 1) through the cathode dark space (the distance separating the negative glow from the surface of the cathode) onto the cathode. The degree of sputtering depends on the conditions prevailing in the discharge, viz: the nature of the cathode material, the type of discharge gas, the pressure and the discharge voltage. The pressure has two direct effects on the sputtering. First, the relatively high pressures of a glow discharge impede the complete escape of sputtered material away from the surface, causing backdiffusion onto the cathode, thereby decreasing the nett rate of erosion. Second, collisions and resonance charge-transfer reactions, such as (l), of the accelerating ions with the gas, considerably diminish their effective kinetic energy. It is generallyAr+ .+ +Are+ A P -+ + Ar'(1)

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Observation and lifetime of autoionising states of Ar produced in a glow discharge ion source

Cited by 7 publications

References 10 publications

Oxidation behaviour of plasma surface alloying on Ti6Al4V alloy

Oxidation behaviour of plasma surface alloying on Ti6Al4V alloy

Ion formation at the boundary between a fast flow glow discharge ion source and a quadrupole mass spectrometer

Cathodic bombardment and sputtering in the 0.5–4.0 torr pressure region of a glow‐discharge ion source

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