Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-28T05:08:12.432Z Has data issue: false hasContentIssue false
  • English
  • Français

Crystallinity Uniformity of Microcrystalline Silicon Thin Films Deposited in Large Area Radio Frequency Capacitively-coupled Reactors

Published online by Cambridge University Press:  01 February 2011

Benjamin Strahm ,
Alan A. Howling  and
Christoph Hollenstein
Benjamin Strahm
Affiliation:
benjamin.strahm@epfl.ch, Ecole Polytechnique Fédérale de Lausanne, Centre de Recherches en Physique des Plasmas, Station 13, Lausanne, CH-1015, Switzerland
Alan A. Howling
Affiliation:
alan.howling@epfl.ch, Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Lausanne, CH-1015, Switzerland
Christoph Hollenstein
Affiliation:
christophe.hollenstein@epfl.ch, Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas, Lausanne, CH-1015, Switzerland
Get access

Abstract

The microcrystalline silicon (μc-Si:H) intrinsic layer for application in micromorph tandem photovoltaic solar cells has to be optimized in order to achieve cost-effective mass production of solar cells in large area, radio frequency, capacitively-coupled PECVD reactors. The optimization has to be performed with regard to the deposition rate as well as to the crystallinity uniformity over the substrate area. The latter condition is difficult to achieve since the optimal solar grade μc-Si:H is deposited at the limit between a-Si:H and μc-Si:H material, where the film crystallinity is very sensitive to the plasma process. In this work, a controlled RF power nonuniformity was generated in a large area industrial reactor. The resulting film uniformity was studied as a function of the deposition regimes. Results show that the higher the input silane concentration, the more the uniformity of the crystallinity is sensitive to the RF power nonuniformity for films deposited at the limit between a-Si:H and μc-Si:H. The effect of the input silane concentration on the microstructure uniformity could be explained on the basis of an analytical plasma chemistry model. This result is important for reactor design. In reactors generating nonuniform plasma the input silane concentration has to be limited to low values in order to deposit films with uniform microstructure. To benefit from the high silane flow rate utilization fraction encountered only for higher input silane concentration, the RF power distribution has to be as uniform as possible over the whole substrate area.

Keywords

plasma-enhanced CVD (PECVD) (deposition)crystallineSi
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1066: Symposium A – Amorphous and Polycrystalline Thin-Film Silicon Science and Technology—2008 , 2008 , 1066-A01-01
Copyright
Copyright © Materials Research Society 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1] Meier, J. Kroll, U. Spitznagel, J. Benagli, S. Roschek, T. Pfanner, G. Ellert, C. Androutsopoulos, G. Hügli, A., Nagel, M. Bucher, C. Feitknecht, L. Büchel, G., and Buechel, A. Proc. 31st IEEE Photovoltaic Specialists Conference, Orlando (USA), 1464 (2005).Google Scholar
[2] Takatsuka, H. Yamauchi, Y. Kawamura, K. Mashima, H. and Takeuchi, Y., Thin Solid Films, 506-507, 13–16 (2006).Google Scholar
[3] Howling, A.A., Sansonnens, L. Ballutaud, J. Grangeon, F. Delachaux, T. Hollenstein, Ch., Daudrix, V. and Kroll, U. 16th European Photovoltaic Solar Energy Conference, Glasgow (UK), 375–379 (2000).Google Scholar
[4] Strahm, B. Howling, A.A., Sansonnens, L. and Hollenstein, Ch., Plasma Sources Sci. Technol., 16, 80–89 (2007).Google Scholar
[5] Howling, A.A., Strahm, B. Colsters, P. Sansonnens, L. and Hollenstein, Ch., Plasma Sources Sci. Technol., 16, 679–696 (2007).Google Scholar
[6] Howling, A.A., Derendinger, L. Sansonnens, L. Schmidt, H. Hollenstein, Ch. Sakanaka, E. and Schmitt, J.P.M., J. Appl. Phys., 97, 123308 (2005).Google Scholar
[7] Sansonnens, L. Strahm, B. Derendinger, L. Howling, A.A., Hollenstein, Ch., Ellert, C. and Schmitt, J.P.M., J. Vac. Sci. Technol. A, 23, 922–926 (2005)Google Scholar
[8] Donker, M.N. van den, Rech, B. Finger, F. Kessels, W.M.M. and Sanden, M.C.M. van de, Appl. Phys. Lett., 87, 263503 (2005).Google Scholar
[9] Sansonnens, L. Howling, A.A. and Hollenstein, Ch., Plasma Sources Sci. Technol., 9, 205–209 (2000).Google Scholar
[10] Droz, C. Vallat-Sauvain, E., Bailat, J. Feitknecht, L. Meier, J. and Shah, A. Solar Energy Mater. Solar Cells, 81, 61–71 (2004).Google Scholar
[11] Vetterl, O. Finger, F. Carius, R. Hapke, P. Houben, L. Kluth, O. Lambertz, A. Mück, A., Rech, B. and Wagner, H. Solar Energy Mater. Solar Cells, 62, 97–108 (2000).Google Scholar
[12] Meiling, H. Sark, W.G.J.H.M. van, Bezemer, J. and Weg, W.F. van der, J. Appl. Phys., 80, 3546–3551 (1996).Google Scholar
[13] Howling, A.A., Sansonnens, L. and Hollenstein, Ch., Thin Solid Films, 515, 5059–5064 (2007).Google Scholar
[14] Howling, A.A., Dorier, J.-L., Hollenstein, Ch., Kroll, U. and Finger, F. J. Vac. Sci. Technol. A, 10, 1080–1085 (1992).Google Scholar
[15] Sansonnens, L. Howling, A.A. and Hollenstein, Ch., Plasma Sources Sci. Technol., 7, 114–118 (1998).Google Scholar
[16] Amanatides, E. Mataras, D. and Rapakoulias, D.E., Thin Solid Films, 383, 15–18 (2001).Google Scholar
[17] Finger, F. Hapke, P. Luysberg, M. Carius, R. Wagner, H. and Scheib, M. Appl. Phys. Lett., 65, 2588–2590 (1994).Google Scholar
[18] Schmidt, H. Sansonnens, L. Howling, A.A., Hollenstein, Ch., Elyaakoubi, M. and Schmitt, J.P.M, J. Appl. Phys., 95, 4559–4564 (2004).Google Scholar
[19] Sansonnens, L. Schmidt, H. Howling, A.A., Hollenstein, Ch., Ellert, C. and Buechel, A. J. Vac. Sci. Technol. A, 24, 1425–1430 (2006).Google Scholar
[20] Sansonnens, L. and Schmitt, J.P.M., Appl. Phys. Lett., 82, 182–184 (2003).Google Scholar