Analytical and Bioanalytical Chemistry

, Volume 406, Issue 29, pp 7455–7462 | Cite as

On copper diffusion in silicon measured by glow discharge mass spectrometry

  • Chiara Modanese
  • Guilherme Gaspar
  • Lars Arnberg
  • Marisa Di Sabatino
Research Paper
First Online:
Received:
Revised:
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Part of the following topical collections:
  1. Emerging Concepts and Strategies in Analytical Glow Discharges

Abstract

Copper contamination occurs frequently in silicon for photovoltaic applications due to its very fast diffusion coupled with a low solid solubility, especially at room temperature. The combination of these properties exerts a challenge on the direct analysis of Cu bulk concentration in Si by sputtering techniques like glow discharge mass spectrometry (GDMS). This work aims at addressing the challenges in quantitative analysis of fast diffusing elements in Si matrix by GDMS. N-type, monocrystalline (Czochralski) silicon samples were intentionally contaminated with Cu after solidification and consequently annealed at 900 °C to ensure a homogeneous distribution of Cu in the bulk. The samples were quenched after annealing to control the extent of the diffusion to the surface prior to the GDMS analyses, which were carried out at different time intervals from within few minutes after cooling onward. The Cu profiles were measured by high-resolution GDMS operating in a continuous direct current mode, where the integration step length was set to ∼0.5 μm over a total sputtered depth of 8–30 μm. The temperature of the samples during the GDMS analyses was also measured in order to evaluate the diffusion. The Cu contamination of n-type Si samples was observed to be highly material dependent. The practical impact of Cu out-diffusion on the calculation of the relative sensitivity factor (RSF) of Cu in Si is discussed.

Keywords

Surface analysis Mass spectrometry Trace elements Glow discharge Fast diffusers/fast diffusing species 
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Notes

Acknowledgments

The authors would like to thank the ‘Norwegian Research Centre for Solar Cell Technology’ (project number 193829), a Centre for Environment-Friendly Energy Research co-sponsored by the Norwegian Research Council and research and industry partners in Norway. Dr. Mari Juel (SINTEF) is gratefully acknowledged for providing the materials.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Chiara Modanese
    • 1
  • Guilherme Gaspar
    • 1
  • Lars Arnberg
    • 1
  • Marisa Di Sabatino
    • 1
  1. 1.Department Materials Science and EngineeringNorwegian University of Science and Technology (NTNU)TrondheimNorway

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