On the transmission function of an ion-energy and mass spectrometer

Hamers, E. A. G.; Sark, W.G.J.H.M. van; Bezemer, Jeff; Goedheer, W. J.; Weg, W. F. van der

doi:10.1016/s0168-1176(97)00285-1

Cited by 58 publications

(48 citation statements)

References 8 publications

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“…As a consequence, the CMA does not contribute to an energy-dependent effect. However, energy-dependent effects can arise from the limited acceptance angle of the system as well as from chromatic abberation due to the retardation or acceleration of the ions in the ion optics 39 . Space charge limitations can arise for higher densities or lower energies inside the PM.…”

Section: Total Detection Efficiency Of the Plasma Monitormentioning

confidence: 99%

Quantitative determination of mass-resolved ion densities in H2-Ar inductively coupled radio frequency plasmas

Sode

Schwarz-Selinger

Jacob

2013

Journal of Applied Physics

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Inductively coupled H 2 -Ar plasmas are characterized by an energy-dispersive mass spectrometer (plasma monitor), a retarding field analyzer, optical emission spectroscopy and a Langmuir probe. A procedure is presented that allows determining quantitatively the absolute ion densities of Ar + , H + , H + 2 , H + 3 and ArH + from the plasma monitor raw signals. The calibration procedure considers the energy and mass-dependent transmission of the plasma monitor. It is shown that an additional diagnostic like a Langmuir probe or a retarding field analyzer is necessary to derive absolute fluxes with the plasma monitor. The conversion from fluxes into densities is based on a sheath and density profile model.Measurements were conducted for a total gas pressure of 1.0 Pa. For pure H 2 plasmas the dominant ion is H + 3 . For mixed H 2 -Ar plasmas the ArH + molecular ion is the most dominant ion species in a wide parameter range. The electron density n e is around 3 × 10 16 m −3 and the electron temperature T e decreases from 5 to 3 eV with increasing Ar content. The dissociation degree was measured by actinometry. It is around 1.7 % nearly independent on Ar content. The gas temperature, estimated by the rotational distribution of the Q-branch lines of the H 2 Fulcher-α diagonal band (v' = v" = 2) is estimated to (540±50) K.

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Section: Total Detection Efficiency Of the Plasma Monitormentioning

confidence: 99%

Quantitative determination of mass-resolved ion densities in H2-Ar inductively coupled radio frequency plasmas

Sode

Schwarz-Selinger

Jacob

2013

Journal of Applied Physics

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“…The floating potential of the substrate holder dummy ranged from −2.4 to −3 V. To maintain constant energy resolution ions are either accelerated or decelerated to a constant pass energy through the 45 ∘ sector field. The voltage of the first element of the extraction lens (extraction) was set to −5 V and the second element (lens1) at −189 V according to the recommendations by Hamers et al to avoid chromatic abberation [10]. The mass-dependent transmission was assumed to be constant.…”

Section: Nitrogen Plasma Exposurementioning

confidence: 99%

“…Therefore dedicated laboratory experiments have been performed to investigate the interaction of W surfaces with N plasmas. Tungsten coated Si samples were exposed to N ions from plasma and ion gun sources at energies from 20 eV to 10 keV and W surface temperatures from 300 to 750 K. After exposure to the N plasma with fluences of up to several 10 23 N m 2 the N content in the samples was measured by nuclear reaction analysis. The sputter erosion was determined by measuring the thickness change of the W layer by RBS.…”

Section: Introductionmentioning

confidence: 99%

Interaction of nitrogen plasmas with tungsten

Schmid¹,

Manhard

Linsmeier

et al. 2010

Nucl. Fusion

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Abstract.The use of nitrogen seeding to reduce the edge plasma temperature has recently been successfully applied in ASDEX Upgrade. While the plasma performance was significantly improved compared to other seeding species like Ar or Ne, questions remained as to the interaction of nitrogen with a tungsten first wall. In particular the formation of thick tungsten nitride layers with reduced melting temperature and increased physical sputtering was a concern. Therefore dedicated laboratory experiments have been performed to investigate the interaction of W surfaces with N plasmas. Tungsten coated Si samples were exposed to N ions from plasma and ion gun sources at energies from 20 eV to 10 keV and W surface temperatures from 300 to 750 K. After exposure to the N plasma with fluences of up to several 10 23 N m 2 the N content in the samples was measured by nuclear reaction analysis. The sputter erosion was determined by measuring the thickness change of the W layer by RBS. The formation of W nitride phases was investigated in separate XPS experiments where the samples were implanted in situ with keV N ions. It was found that only very small fractions of N are accumulated in the W surface and that N is bound in a nitride state. At temperatures above 600 K the nitrides are no longer stable which further reduces the N uptake into the W. Moreover the accumulation of N in the surface leads to a decrease in W physical sputtering due to the lower W concentration at the surface.

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“…The IEDFs of singly and doubly charged Cr ions comprises low energy peaks and very pronounced high-energy tails that completely dominate the ion energy spectrum for energies larger than 5 eV. The [18,19]) convoluted with (i) the probability function for electron impact ionization (which is the dominant ionization mechanism in HIPIMS discharge [20]), (ii) the probability function for collisions of metal ions with Ar neutrals, and finally (iii) the energy transmission function of the spectrometer [21]. In parallel, a contribution from the back-reflected metal ions (i.e., ions that were trapped by the negative potential at the cathode and accelerated towards the target) to the high energy tail is also expected.…”

Section: Current and Voltage Waveformsmentioning

confidence: 99%