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Methodology to analyse small silicon samples by glow discharge mass spectrometry using a thin wafer mask.

Modanese C, Arnberg L, Di Sabatino M - MethodsX (2015)

Bottom Line: From time to time, there is the need to analyse smaller samples with this technique, and we present here a methodology to analyse samples of 9-20 mm diameter through the use of thin masks.The use of masks in this work includes the following customization:•The choice of highly-pure Si as mask material, to decrease the chance of interferences with the Si samples.•The use of a hole in the mask of the same size as the discharge area.This implies that the mask material is not sputtered, thus decreasing chances for contamination from the mask itself.

View Article: PubMed Central - PubMed

Affiliation: Norwegian University of Science and Technology (NTNU), Department of Materials Science and Engineering, 7491 Trondheim, Norway.

ABSTRACT
Glow discharge mass spectrometry (GDMS) is widely used for trace element analysis of bulk solid samples. The geometry of the GD source limits the minimum size of the sample, which for the instrument used in this work (ThermoElementGD) is 20 mm in diameter. From time to time, there is the need to analyse smaller samples with this technique, and we present here a methodology to analyse samples of 9-20 mm diameter through the use of thin masks. Thin masks have been previously used mostly as secondary cathode for the analysis of non-conducting materials, with hole size smaller than the area of the glow discharge. The use of masks in this work includes the following customization:•The choice of highly-pure Si as mask material, to decrease the chance of interferences with the Si samples.•The use of a hole in the mask of the same size as the discharge area. This implies that the mask material is not sputtered, thus decreasing chances for contamination from the mask itself.

No MeSH data available.


Concentration of phosphorus over repetition #, analysed with 6, 8 and 10 mm hole diameter and without any mask. It can be seen that the instabilities are greater for the 6 and 10 mm masks.
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fig0015: Concentration of phosphorus over repetition #, analysed with 6, 8 and 10 mm hole diameter and without any mask. It can be seen that the instabilities are greater for the 6 and 10 mm masks.

Mentions: With either the largest hole (10 mm Ø) or the smallest hole (6 mm Ø), the discharge voltage is sensibly lower, and several isotope peaks present one or two high spikes, not homogeneously distributed over the mass range and over repeated analyses in the same crater. Furthermore, the background noise with the 6 mm Ø mask is sensibly higher, even hiding the real isotope peak in some repetitions. This was observed for all the impurity isotopes, at different sputtering times, and it appears to occur randomly. The measured concentrations of phosphorus are reported in Fig. 3 as an example of the instabilities in the signal during the analysis with the 6 mm and 10 mm hole diameter masks compared to analysis with the 8 mm hole diameter mask or without the mask.


Methodology to analyse small silicon samples by glow discharge mass spectrometry using a thin wafer mask.

Modanese C, Arnberg L, Di Sabatino M - MethodsX (2015)

Concentration of phosphorus over repetition #, analysed with 6, 8 and 10 mm hole diameter and without any mask. It can be seen that the instabilities are greater for the 6 and 10 mm masks.
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644257&req=5

fig0015: Concentration of phosphorus over repetition #, analysed with 6, 8 and 10 mm hole diameter and without any mask. It can be seen that the instabilities are greater for the 6 and 10 mm masks.
Mentions: With either the largest hole (10 mm Ø) or the smallest hole (6 mm Ø), the discharge voltage is sensibly lower, and several isotope peaks present one or two high spikes, not homogeneously distributed over the mass range and over repeated analyses in the same crater. Furthermore, the background noise with the 6 mm Ø mask is sensibly higher, even hiding the real isotope peak in some repetitions. This was observed for all the impurity isotopes, at different sputtering times, and it appears to occur randomly. The measured concentrations of phosphorus are reported in Fig. 3 as an example of the instabilities in the signal during the analysis with the 6 mm and 10 mm hole diameter masks compared to analysis with the 8 mm hole diameter mask or without the mask.

Bottom Line: From time to time, there is the need to analyse smaller samples with this technique, and we present here a methodology to analyse samples of 9-20 mm diameter through the use of thin masks.The use of masks in this work includes the following customization:•The choice of highly-pure Si as mask material, to decrease the chance of interferences with the Si samples.•The use of a hole in the mask of the same size as the discharge area.This implies that the mask material is not sputtered, thus decreasing chances for contamination from the mask itself.

View Article: PubMed Central - PubMed

Affiliation: Norwegian University of Science and Technology (NTNU), Department of Materials Science and Engineering, 7491 Trondheim, Norway.

ABSTRACT
Glow discharge mass spectrometry (GDMS) is widely used for trace element analysis of bulk solid samples. The geometry of the GD source limits the minimum size of the sample, which for the instrument used in this work (ThermoElementGD) is 20 mm in diameter. From time to time, there is the need to analyse smaller samples with this technique, and we present here a methodology to analyse samples of 9-20 mm diameter through the use of thin masks. Thin masks have been previously used mostly as secondary cathode for the analysis of non-conducting materials, with hole size smaller than the area of the glow discharge. The use of masks in this work includes the following customization:•The choice of highly-pure Si as mask material, to decrease the chance of interferences with the Si samples.•The use of a hole in the mask of the same size as the discharge area. This implies that the mask material is not sputtered, thus decreasing chances for contamination from the mask itself.

No MeSH data available.