TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Hoffmann, V. A1 - Wetzig, K. A1 - Steers, E.B.M. T1 - Investigations of the effect of hydrogen in an argon glow discharge N2 - Clear evidence of the effects caused by hydrogen, introduced in different forms in an analytical glow discharge source (GDS) operated with argon, is presented for the different matrix elements copper, stainless steel, titanium, aluminium and silicon. When hydrogen is present even in small quantities in argon, not only are there significant changes in the emission line intensities of most elements (analyte and plasma species), but also new spectral features, such as emission bands of new compounds (hydrides of sputtered sample constituents) and a continuous background in the range ~220–440 nm. Moreover, the discharge current (the dependent parameter in our experiments) decreases with increasing hydrogen concentration. Different modes of hydrogen introduction, externally in gaseous form or sputtered as a sample constituent, cause very similar effects in terms of discharge current, line intensity (of analyte and plasma gas) and emission continua, which implies similar changes in the discharge processes in the two cases. The excitation of the hydrogen continuum appears to quench the population of the argon metastables (11.55 and 11.72 eV) and, consequently, other elementary processes in the plasma in which the argon metastables take part, but to a different extent for each analyte. PY - 2000 U6 - https://doi.org/10.1039/b002367l SN - 0267-9477 SN - 1364-5544 IS - 15 SP - 1075 EP - 1080 PB - Royal Society of Chemistry CY - London AN - OPUS4-964 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Hoffmann, V. A1 - Wetzig, K. A1 - Steers, E.B.M. T1 - Emission spectra of copper and argon in an argon glow discharge containing small quantities of hydrogen N2 - The influence of hydrogen contained in a sample or otherwise introduced into a glow discharge source (GDS) is here extensively experimentally presented for the case of copper as a sample by means of the addition of small quantities of molecular hydrogen (<1% relative partial pressure) to the argon carrier gas. The progressive addition of molecular hydrogen causes different intensity changes particular to the individual lines of different species such as atomic (Cu I) and ionic (Cu II) copper, and also atomic (Ar I) and ionic (Ar II) argon. Some interesting features of the emission spectrum of hydrogen such as its line, band and even continuum spectrum are observed. It was also found that the depth resolution becomes worse even at very low concentrations of hydrogen. PY - 2000 U6 - https://doi.org/10.1039/b001565m SN - 0267-9477 SN - 1364-5544 IS - 15 SP - 951 EP - 958 PB - Royal Society of Chemistry CY - London AN - OPUS4-965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Steers, E.B.M. A1 - Hoffmann, V. A1 - Unger, Wolfgang A1 - Paatsch, Wolfgang A1 - Wetzig, K. T1 - Influence of hydrogen on the analytical figures of merit of glow discharge optical emission spectroscopy - friend or foe? PY - 2003 U6 - https://doi.org/10.1039/b305384a SN - 0267-9477 SN - 1364-5544 VL - 18 SP - 521 EP - 526 PB - Royal Society of Chemistry CY - London AN - OPUS4-2290 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, V. A1 - Dorka, R. A1 - Wilken, L. A1 - Hodoroaba, Vasile-Dan A1 - Wetzig, K. T1 - Present possibilities of thin-layer analysis by GDOES N2 - The analysis of thin layers of thickness 100 nm has become a new field of application for glow discharge optical emission spectroscopy (GDOES). In this paper an overview is given of the experiences and possibilities gained by the authors in later years at their research, development and application of GDOES. During GDOES analysis of a multilayer system the depth resolution was determined using the inverse maximal slope method. Under optimized discharge conditions a depth resolution of 25 nm at 100 nm depth was achieved. The gas flow in a Grimm-type source for glow discharge mass spectrometry (GDMS) was simulated and a correlation between calculated pressure and crater shape was found. Cleanness of the sample and source turned out to be essential for a fast stabilization time and reduction of the influence of light elements and molecules. Thereby, a 10 nm layer at the top surface of a sample could be quantified. Apart from the influence of density, the reflectivity of the sample surface is discussed. It is shown that a high sample reflectivity can cause up to 100% more light to be measured by the spectrometer. KW - GDOES KW - GDMS KW - Thin-layer analysis PY - 2003 U6 - https://doi.org/10.1002/sia.1575 SN - 0142-2421 SN - 1096-9918 VL - 35 IS - 7 SP - 575 EP - 582 PB - Wiley CY - Chichester AN - OPUS4-2624 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Klemm, D. A1 - Reinholz, Uwe A1 - Strub, E. A1 - Röhrich, J. A1 - Bohne, W. A1 - Hoffmann, V. A1 - Wetzig, K. T1 - Potential candidates of certified reference material for determination of hydrogen concentration with glow discharge optical emission spectrometry (GD-OES) - a feasibility study N2 - Three different coatings/layers have been found in a feasibility study as potential candidates for certified reference materials for the determination of hydrogen concentration by GD-OES: (i) electroplated zinc, (ii) carbon-rich coatings and (iii) amorphous silicon layers. KW - CRM KW - Hydrogen KW - GDS PY - 2008 U6 - https://doi.org/10.1039/b717924c SN - 0267-9477 SN - 1364-5544 VL - 23 SP - 460 EP - 462 PB - Royal Society of Chemistry CY - London AN - OPUS4-17335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Unger, Wolfgang A1 - Jenett, H. A1 - Hoffmann, V. A1 - Hagenhoff, B. A1 - Kayser, S. A1 - Wetzig, K. T1 - Depth profiling of electrically non-conductive layered samples by RF-GDOES and HFM plasma SNMS N2 - The work is intended to compare the capabilities of two similar depth profiling techniques to analyse electrically non-conductive samples. In order to get a better evaluation of the depth resolution, various multilayer sandwiches, such as SiO2/TiO2 and Si3N4/SiO2 deposited on glass substrates have been investigated. Optimised depth profiles are presented for both methods, glow discharge optical emission spectrometry (GDOES) and radiofrequency mode (known as “HFM” in the SNMS literature) of plasma secondary neutral mass spectrometry (SNMS). The optimisation procedure, necessary to get the best set of plasma parameters, which result in the optimal depth resolution, is also described for one selected sample. Additionally, sputtering crater profilometry was carried out in order to check out the flatness of the sputtered crater. The influence of the thickness of the sample substrate on the sputtering rate is discussed. Finally, advantages and disadvantages of the use of these two depth profiling methods, especially for the non-conductive samples, are concluded from this comparative study. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of a cross-sectioned sample was carried out in order to get supplementary information. KW - rf-Glow discharge KW - HFM plasma SNMS KW - Non-conductive layered samples KW - Depth resolution KW - Crater shape KW - ToF-SIMS PY - 2001 U6 - https://doi.org/10.1016/S0169-4332(01)00259-8 SN - 0169-4332 SN - 1873-5584 VL - 179 IS - 1-4 SP - 30 EP - 37 PB - North-Holland CY - Amsterdam AN - OPUS4-6882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hodoroaba, Vasile-Dan A1 - Steers, E.B.M. A1 - Hoffmann, V. A1 - Wetzig, K. T1 - The effect of small quantities of hydrogen on a glow discharge in neon. Comparison with the argon case N2 - In order to gain an insight into the numerous effects caused by the addition of hydrogen to an argon glow discharge, comparison experiments have been made with neon as carrier gas. In some cases the effects are diminished or even disappear. Using various bulk samples, such as copper, steel and titanium, sputtered in a neon glow discharge, the intensities of the analytical lines are affected by the presence of hydrogen in different ways from argon; the dependent parameter (the discharge current in this work) and the sputtering rate vary less than in argon. The crater shape and roughness are also affected and these effects are discussed qualitatively. Probably the most important spectral feature caused by hydrogen in the case of a discharge in argon is the emission of a continuous background. This does not appear in neon under similar discharge conditions and only weakly at high hydrogen concentrations. This supports the suggestion, made in previous work, that an effective quenching process of the argon metastables (11.55 and 11.72 eV) is Penning excitation of the hydrogen molecules, and subsequent decay to a repulsive state with emission of the continuum; in neon the energy match does not occur. It was found with neon, as with argon, that similar features occur as when hydrogen is introduced in different ways into the glow discharge: as a molecular gas contamination or as a constituent of the sample. Glow discharge mass spectrometry (GD-MS) experiments carried out with both argon and neon support the results obtained by optical emission spectrometry (OES) and provide further relevant information. PY - 2001 U6 - https://doi.org/10.1039/b007527m SN - 0267-9477 SN - 1364-5544 VL - 16 SP - 43 EP - 49 PB - Royal Society of Chemistry CY - London AN - OPUS4-6887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -