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Sub-Surface Equilibration of Hydrogen with the a-Si:H Network Under Film Growth Conditions

Published online by Cambridge University Press:  01 January 1993

ILSIN An ,
Y.M. Li ,
C.R. Wronski  and
R. W. Collins
ILSIN An
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
Y.M. Li
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
C.R. Wronski
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
R. W. Collins
Affiliation:
Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802
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Abstract

In this study we characterize hydrogen diffusion and reaction processes in the near-surface (top 200 Å) of a-Si:H that lead to network equilibration under standard conditions of plasma-enhanced chemical vapor deposition (PECVD). Real time spectroscopic ellipsometry (SE) is used to provide continuous kinetic information on the near-surface conversion of Si-Si to Si-H bonds during exposure of in situ-prepared films at 250°C to filament-generated atomic H. We have found that for optimum PECVD a-Si:H, the formation of additional Si-H bonds is limited by the capture of H at trapping sites, and the rapid diffusion process (D>10-14 cm2/s) by which H reaches the site is not detected optically. Deep trapping occurs at a rate of ∼10 3 s-1 under our filament conditions, estimated to generate ∼1020 cm-3 mobile H in the near-surface of the film. Finally, more than 1021 cm-3 additional H atoms are trapped with emission rates <2×10-7 s-1, suggesting trap depths >2.0 eV. Shallower traps are also detected at lower concentration.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 297: Symposium A – Amorphous Silicon Technology - 1993 , 1993 , 43
Copyright
Copyright © Materials Research Society 1993

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References

REFERENCES

[1] Gallagher, A., Mater. Res. Soc. Symp. Proc. 70, 3 (1986).Google Scholar
[2] Tanaka, K. and Matsuda, A., Mater. Sci. Rep. 2, 139 (1987).Google Scholar
[3] Street, R.A., Phys. Rev. B 43, 2454 (1991).Google Scholar
[4] Li, Y., An, I., Gunes, M., Dawson, R., Collins, R.W., and Wronski, C.R., Mater. Res. Soc. Symp. Proc. 258, 27 (1992); An, I., Li, Y., Wronski, C.R., and Collins, R.W., p. 57.Google Scholar
[5] Collins, R.W., Rev. Sci. Instrum. 61, 2029 (1990).Google Scholar
[6] Branz, H.M., Asher, S.E., and Nelson, B.P., Phys. Rev. B 47, 7061 (1993).Google Scholar
[7] Richards, P.M., J. Appl. Phys. 70, 4258 (1991).Google Scholar
[8] Jackson, W.B. and Tsai, C.C., Phys. Rev. B 45, 6564 (1992).Google Scholar
[9]See, e.g., Santos, P.V. and Jackson, W.B., Mater. Res. Soc. Symp. Proc. 258, 425 (1992).Google Scholar
[10] Zhang, S.B., Jackson, W.B., and Chadi, D.J., Phys. Rev. Lett. 65, 2575 (1990).Google Scholar
[11] Zafar, S. and Schiff, E.A., Phys. Rev. B 40, 5235 (1990).Google Scholar