Electrical measurements at radio frequency glow discharges for spectroscopy

Wilken, L.; Hoffmann, Volker; Wetzig, K.

doi:10.1016/j.sab.2007.07.003

Cited by 21 publications

(15 citation statements)

References 88 publications

(179 reference statements)

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“…For a free running generator no matching box is needed because the source is a part of the oscillating circuit. 36,37 This simplifies the generator operation and reduces the stabilisation time. The oscillation frequency changes slightly and thus compensates the variation of the plasma impedance.…”

Section: Optimization Of the Experimental Setupmentioning

confidence: 99%

Electrical properties of the µs pulsed glow discharge in a Grimm-type source: comparison of dc and rf modes

Efimova

Hoffmann

Eckert

2011

J. Anal. At. Spectrom.

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The electrical properties, in particular the U-I characteristics, current and voltage signal shapes within the pulse, are important parameters for the understanding of the processes taking place in the pulsed glow discharge (PGD). The electrical properties are also closely related to the analytical performance of the PGD such as sputtering rates, crater shapes and emission yields. Moreover, the dependence of the U-I plots on the density of the discharge gas can be used to estimate the gas temperature. This result is relevant for the analysis of thermally fragile samples. Nevertheless, there is a lack of PGD studies where the current and voltage signals are considered in detail. Therefore, this article is dedicated to the electrical properties of PGD. The influence of the PGD parameters (duty cycle and pulse duration) on the electrical properties is examined. The results highlight the optimum parameters for particular analytical applications. The question, whether direct current (dc) and radio frequency (rf) discharges behave similarly is also discussed and all experiments are performed for both modes. The comparative studies reveal strong similarities between dc and rf pulsed discharges.

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Section: Optimization Of the Experimental Setupmentioning

confidence: 99%

Electrical properties of the µs pulsed glow discharge in a Grimm-type source: comparison of dc and rf modes

Efimova

Hoffmann

Eckert

2011

J. Anal. At. Spectrom.

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“…For ultra thin non-conductive layers the capacity is very high, and thus, the voltage drop is negligible. 12,25 But in the case of thick nonconductive samples V out /V in is less than 1 due to the low sample capacitance and the resultant voltage drop with the consequent lower power deposition into the discharge plasma. This study is based on a simplified equivalent electrical circuit for the system, which has been described previously by Therese et al, 12 taking into account the capacitances of the discharge cell, sample and probes used.…”

Section: Electrical Measurements: Voltage Transfer Coefficientmentioning

confidence: 99%

Improvement of the analytical performance in RF-GD-OES for non-conductive materials by means of thin conductive layer deposition and the presence of a magnetic field

Alberts

Thérèse

Guillot

et al. 2010

J. Anal. At. Spectrom.

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Radiofrequency glow discharge coupled to optical emission spectrometry (RF-GD-OES) is a wellknown analytical technique for bulk, surface and depth profiling and can be applied in the direct analysis of conductors, semiconductors and non-conductors, however for the latter case limits still exist. The problem is related to the low power deposited in the plasma due to a voltage drop developing inside the material. The voltage transfer coefficient, defined as the ratio between the peak voltage at the front and at the back of the sample. This depends on the sample capacitance, which itself is dependant on the material surface, thickness and permittivity. In order to improve the analysis of such non-conductive materials, thin conductive top layers are deposited on both sides of the sample which increases their voltage transfer coefficient. The aim of this work is to study the influence of these thin layers on the optical and electrical signals measured for the samples with varying thickness and diameter. Additionally, the influence of applying a magnetic field during the GD analysis has been evaluated as an attractive option in order to obtain higher sputtering rates, together with better ionisation and excitation efficiencies and as a consequence give improved emission intensities.

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“…However, there are also non-conducting oxide films whose dc bias voltages can not be determined. Fortunately, interesting progresses both in instrumentation 30 and in the development of numerical and electrical simulations 31 are being made to solve remained limitations in the analysis of non-conducting samples.…”

Section: Gd-oes Calibration Of Oxygenmentioning

confidence: 99%

“…The Al/O ratio reached a constant value at the same time that hydrogen concentration diminished from 3 to 0.6 mass% (although hydrogen quantification should be taken with care). Wilken et al 30 have recently reported that the porous Al 2 O 3 layer of the electrochemical oxidation is usually densified by water vapour to Bo ¨hmit (2 AlO(OH)). The challenging differentiation of aluminium oxide, oxo-hydroxides and hydroxides by XPS was carried out using Thomas' protocol.…”

Section: Compositional Depth Profiling Analysis Of Anodic Alumina Filmsmentioning

confidence: 99%

In-depth profile analysis of oxide films by radiofrequency glow discharge optical emission spectrometry (rf-GD-OES): possibilities of depth-resolved solid-state speciation

Malherbe

Fernández

Martínez

et al. 2008

J. Anal. At. Spectrom.

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Electrical measurements at radio frequency glow discharges for spectroscopy

Cited by 21 publications

References 88 publications

Electrical properties of the µs pulsed glow discharge in a Grimm-type source: comparison of dc and rf modes

Electrical properties of the µs pulsed glow discharge in a Grimm-type source: comparison of dc and rf modes

Improvement of the analytical performance in RF-GD-OES for non-conductive materials by means of thin conductive layer deposition and the presence of a magnetic field

In-depth profile analysis of oxide films by radiofrequency glow discharge optical emission spectrometry (rf-GD-OES): possibilities of depth-resolved solid-state speciation

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