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Analysis of Compositionally and Structurally Graded Si:H and Si1−xGex:H Thin Films by Real Time Spectroscopic Ellipsometry

Published online by Cambridge University Press:  01 February 2011

Nikolas Podraza
Affiliation:
[email protected], The Pennsylvania State University, Materials Research Institute, 272 Materials Research Lab, University Park, PA, 16802, United States
Jing Li
Affiliation:
[email protected], The Pennsylvania State University, Materials Research Institute, University Park, PA, 16802, United States
Christopher R. Wronski
Affiliation:
[email protected], The Pennsylvania State University, Materials Research Institute, University Park, PA, 16802, United States
Mark W. Horn
Affiliation:
[email protected], The Pennsylvania State University, Materials Research Institute, University Park, PA, 16802, United States
Elizabeth C. Dickey
Affiliation:
[email protected], The Pennsylvania State University, Materials Research Institute, University Park, PA, 16802, United States
Robert W. Collins
Affiliation:
[email protected], University of Toledo, Department of Physics and Astronomy, Toledo, OH, 43606, United States
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Abstract

Silicon-germanium (Si1−x Gex :H) thin films have been prepared by plasma enhanced chemical vapor deposition of SiH4 and GeH4 and measured during growth using real time spectroscopic ellipsometry. A two-layer virtual interface analysis has been applied to study the structural evolution of Si:H films prepared in multistep processes utilizing alternating intermediate and low H2-dilution material layers, which have been designed to produce predominately amorphous films with a controlled distribution of microcrystalline particles. The compositional evolution of alloy-graded a-Si1−x Gex :H has been studied as well using similar methods. In each case, depth profiles of microcrystalline content, f μc , or Ge content, x, have been extracted. Additionally, real time spectroscopic ellipsometry has been used to monitor post-deposition exposure of a-Si:H, a-Si1−xGex:H, and a-Ge:H films to a hydrogen plasma in situ in order to determine sub-surface amorphous film modification similar to that which would occur when a highly H2-diluted layer is deposited on a layer prepared with lower dilution. These analyses provide guidance for enhanced performance of Si:H based solar cells, through controlled bandgap grading using compositionally graded amorphous binary alloys (a-Si1−xGex :H) or the incorporation of controlled fractions of microcrystallites into bulk amorphous i-layer materials, and by providing a fundamental understanding of the modification of component layers during the deposition of subsequent layers in multilayer stacks.

Type
Research Article
Copyright
Copyright © Materials Research Society 2008

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References

REFERENCES

1. Fujiwara, H. Koh, J. and Collins, R. W. Thin Solid Films 313-314, 474 (1998).Google Scholar
2. Ferlauto, A. S. Ferreira, G. M. Koval, R. J. Pearce, J. M. Wronski, C. R. Collins, R. W. Al-Jassim, M. M., and Jones, K. M. Thin Solid Films 455-456, 665 (2004).Google Scholar
3. An, I. Zapien, J. Chen, C. Ferlauto, A. and Collins, R. W. Thin Solid Films 455-456, 132 (2004).Google Scholar
4. Collins, R. W. Ferlauto, A. S. Ferreira, G. M. Chen, C. Koh, J. Koval, R. Lee, Y. Pearce, J. M. and Wronski, C. R. Solar Energy Mater. Solar Cells 78, 143 (2003).Google Scholar
5. Podraza, N. J. Wronski, C. R. Horn, M. W. and Collins, R. W. Mater. Res. Soc. Symp. Proc. 910, A.10.1.1 (2006).Google Scholar
6. Ferlauto, A. S. Ferreira, G. M. Pearce, J. M. Wronski, C. R. Collins, R. W. Deng, X. and Ganguly, G. J. Appl. Phys. 92, 2424 (2002).Google Scholar
7. Pearce, J. M. Podraza, N. Collins, R. W. Al-Jassim, M. M., Jones, K. M. Deng, J. and Wronski, C. R. J. Appl. Phys. 101, 114301 (2007).Google Scholar