Applied Physics B

, 125:114 | Cite as

Optimization of ALD \(\hbox {Al}_{2}\hbox {O}_{3}\) process parameters for passivation of c-silicon and its implementation on industrial monocrystalline silicon solar cell

  • Akansha Bansal
  • Prashant Singh
  • Rajesh Kumar JhaEmail author
  • B. R. Singh


Effect of process parameters on \(\hbox {Al}_{2}\hbox {O}_{3}\) deposited using Atomic Layer Deposition (ALD) for the surface passivation of c-silicon surface has been investigated. Surface passivation properties of \(\hbox {Al}_{2}\hbox {O}_{3}\) have been measured by evaluating the minority carrier lifetime and interface charges at the \(\hbox {Si}/\hbox {Al}_{2}\hbox {O}_{3}\) interface. It has been observed that surface passivation properties of \(\hbox {Al}_{2}\hbox {O}_{3}\) are strongly dependent on process parameters such as substrate temperature, annealing temperature, and thickness of the deposited \(\hbox {Al}_{2}\hbox {O}_{3}\) film. Minority carrier lifetime, effective charge density (\(Q_{{\mathrm{eff}}}\)), and interface defect density (\(D _{{\mathrm{it}}}\)) were observed to vary from 180 to \(355\,\upmu \hbox {s}\), \(-\,2.3 \times 10^{12}\) to \(-1.46 \times 10^{13}\,\hbox {cm}^{-2}\) and \(1.2 \times 10^{9}\) to \(1.9\times 10^{10}\,\hbox {eV}^{-1}\,\hbox {cm}^{-2}\), respectively, for various process parameters. \(\hbox {Al}_{2}\hbox {O}_{3}\) film based on the optimized process parameters were then used as a passivation layer in fabricating industrial PERC solar cells. Effect of \(\hbox {Al}_{2}\hbox {O}_{3}\) passivation in PERC solar cells has been demonstrated by comparing the characteristics of the PERC solar cells with that of the standard Al BSF solar cells. An efficiency improvement of \(\sim 0.8\%\) has been observed in passivated emitter rear cells (PERC) solar cells as compared to the standard aluminum back surface field (Al BSF) solar cells.



The authors would like to express their sincere thanks to Prof. Nagabhushan, Director, Indian Institute of Information Technology-Allahabad for his constant encouragement and support. Authors would also like to thank Prof. Hirnmay Saha (Head-Centre of Excellence for Green Energy and Sensor Systems, IIEST, Kolkata), Dr. A. K. Saxsena (Director BHEL-ASSCP, Gurugram) and their teams for providing lab, industrial facilities, and support. Thanks are also due to Mr. Upendra Joshi and Mr. Deepak Shukla for their help and assistance. This research was supported by Solar Energy Research Initiative (SERI), Department of Science and Technology, Govt. of India under the sanction letter DST/SERI/2k12/63(G).


  1. 1.
    R. Hezel, K. Jaeger, Low-temperature surface passivation of silicon for solar cells. J. Electrochem. Soc. 136(2), 518–523 (1989)CrossRefGoogle Scholar
  2. 2.
    G. Agostinelli, A. Delabie, P. Vitanov, Z. Alexieva, H.F.W. Dekkers, S. De Wolf, G. Beaucarne, Very low surface recombination velocities on p-type silicon wafers passivated with a dielectric with fixed negative charge. Sol. Energy Mater. Sol. Cells 90(18), 3438–3443 (2006)CrossRefGoogle Scholar
  3. 3.
    B. Hoex, S.B.S. Heil, E. Langereis, M.C.M. Van de Sanden, W.M.M. Kessels, Ultralow surface recombination of c Si substrates passivated by plasma-assisted atomic layer deposited \(\text{ Al }_{2}\text{ O }_{3}\). Appl. Phys. Lett. 89(4), 042112 (2006)ADSCrossRefGoogle Scholar
  4. 4.
    B. Hoex, J.J.H. Gielis, M.C.M. Van de Sanden, W.M.M. Kessels, On the c Si surface passivation mechanism by the negative-charge-dielectric \(\text{ Al }_{2}\text{ O }_{3}\). J. Appl. Phys. 104(11), 113703 (2008)ADSCrossRefGoogle Scholar
  5. 5.
    J. Benick, A. Richter, M. Hermle, S.W. Glunz, Thermal stability of the \(\text{ Al }_{2}\text{ O }_{3}\) passivation on p-type silicon surfaces for solar cell applications. physica status solidi (RRL) Rapid Res. Lett. 3(7–8), 233–235 (2009)ADSCrossRefGoogle Scholar
  6. 6.
    G. Dingemans, P. Engelhart, R. Seguin, M.M. Mandoc, M.C.M. van de Sanden, W.M.M. Kessels, Comparison between \(\text{ Al }_{2}\text{ O }_{3}\) surface passivation films deposited with thermal ald, plasma ald and pecvd. in 35th IEEE PVSC, (Honolulu, Hawaii, 2010), pp. 20–25Google Scholar
  7. 7.
    G. Dingemans, R. Seguin, P. Engelhart, M.C.M. Van De Sanden, W.M.M. Kessels, Silicon surface passivation by ultrathin \(\text{ Al }_{2}\text{ O }_{3}\) films synthesized by thermal and plasma atomic layer deposition. physica status solidi (RRL) Rapid Res. Lett. 4(1–2), 10–12 (2010)ADSCrossRefGoogle Scholar
  8. 8.
    J. Schmidt, B. Veith, R. Brendel, Effective surface passivation of crystalline silicon using ultrathin \(\text{ Al }_{2}\text{ O }_{3}\) films and \(\text{ Al }_{2}\text{ O }_{3}/\text{ SiNx }\) stacks. physica status solidi (RRL) Rapid Res. Lett. 3(9), 287–289 (2009)CrossRefGoogle Scholar
  9. 9.
    S. Dauwe, L. Mittelstädt, A. Metz, R. Hezel, Experimental evidence of parasitic shunting in silicon nitride rear surface passivated solar cells. Prog. Photovolt. Res. Appl. 10(4), 271–278 (2002)CrossRefGoogle Scholar
  10. 10.
    B. Hoex, J. Schmidt, R. Bock, P.P. Altermatt, M.C.M. Van De Sanden, W.M.M. Kessels, Excellent passivation of highly doped p-type Si surfaces by the negative-charge-dielectric \(\text{ Al }_{2}\text{ O }_{3}\). Appl. Phys. Lett. 91(11), 112107 (2007)ADSCrossRefGoogle Scholar
  11. 11.
    J. Benick, B. Hoex, M.C.M. Van de Sanden, W.M.M. Kessels, O. Schultz, S.W. Glunz, High efficiency n-type si solar cells on \(\text{ Al }_{2}\text{ O }_{3}\)-passivated boron emitters. Appl. Phys. Lett. 92(25), 253504 (2008)ADSCrossRefGoogle Scholar
  12. 12.
    G. Dingemans, W. Beyer, M.C.M. Van de Sanden, W.M.M. Kessels, Hydrogen induced passivation of Si interfaces by \(\text{ Al }_{2}\text{ O }_{3}\) films and \(\text{ SiO }_{2}/\text{ Al }_{2}\text{ O }_{3}\) stacks. Appl. Phys. Lett. 97(15), 152106 (2010)ADSCrossRefGoogle Scholar
  13. 13.
    D. Lei, Y. Xuegong, L. Song, G. Xin, G. Li, D. Yang, Modulation of atomic-layer-deposited \(\text{ Al }_{2}\text{ O }_{3}\) film passivation of silicon surface by rapid thermal processing. Appl. Phys. Lett. 99(5), 052103 (2011)ADSCrossRefGoogle Scholar
  14. 14.
    J. Frascaroli, G. Seguini, E. Cianci, D. Saynova, J. van Roosmalen, M. Perego, Surface passivation for ultrathin \(\text{ Al }_{2}\text{ O }_{3}\) layers grown at low temperature by thermal atomic layer deposition. Physica status solidi (a) 210(4), 732–736 (2013)ADSCrossRefGoogle Scholar
  15. 15.
    G. Seguini, E. Cianci, C. Wiemer, D. Saynova, J.A.M. Van Roosmalen, M. Perego, Si surface passivation by \(\text{ Al }_{2}\text{ O }_{3}\) thin films deposited using a low thermal budget atomic layer deposition process. Appl. Phys. Lett. 102(13), 131603 (2013)ADSCrossRefGoogle Scholar
  16. 16.
    H. Lee, T. Tachibana, N. Ikeno, H. Hashiguchi, K. Arafune, H. Yoshida, S. Satoh, T. Chikyow, A. Ogura, Interface engineering for the passivation of c-Si with \(\text{ O }_{3}\)-based atomic layer deposited \(\text{ AlOx }\) for solar cell application. Appl. Phys. Lett. 100(14), 143901 (2012)ADSCrossRefGoogle Scholar
  17. 17.
    A.W. Blakers, A. Wang, A.M. Milne, J. Zhao, M.A. Green, 22.8 efficient silicon solar cell. Appl. Phys. Lett. 55(13), 1363–1365 (1989)ADSCrossRefGoogle Scholar
  18. 18.
    R. Preu, S.W. Glunz, S. Schäfer, R. Lüdemann, W. Wettling, W. Pfleging, Laser ablation-a new low-cost approach for passivated rear contact formation in crystalline silicon solar cell technology. in Proceedings of the 16th European Photovoltaic Solar Energy Conference, (2000), p. 1181–1184Google Scholar
  19. 19.
    S. Gatz, H. Hannebauer, R. Hesse, F. Werner, A. Schmidt, T. Dullweber, J. Schmidt, K. Bothe, R. Brendel, 19.4%-efficient large-area fully screen-printed silicon solar cells. physica status solidi (RRL) Rapid Res. Lett. 5(4), 147–149 (2011)ADSCrossRefGoogle Scholar
  20. 20.
    E. Schneiderlöchner, R. Preu, R. Lüdemann, S.W. Glunz, Laser-fired rear contacts for crystalline silicon solar cells. Prog. Photovol. Res. Appl. 10(1), 29–34 (2002)CrossRefGoogle Scholar
  21. 21.
    Screen-printed solar cells institut for solarenergieforschung hameln. Accessed on 25 May 2017Google Scholar
  22. 22.
    J.L. Van Hemmen, S.B.S. Heil, J.H. Klootwijk, F. Roozeboom, C.J. Hodson, M.C.M. Van de Sanden, W.M.M. Kessels, Plasma and thermal ald of \(\text{ Al }_{2}\text{ O }_{3}\) in a commercial 200 mm ald reactor. J. Electrochem. Soc. 154(7), G165–G169 (2007)CrossRefGoogle Scholar
  23. 23.
    S. Bordihn, I. Kiesow, V. Mertens, P. Engelhart, J.W. Müller, W.M.M. Kessels, Impact of the deposition and annealing temperature on the silicon surface passivation of ald \(\text{ Al }_{2}\text{ O }_{3}\) films. Energy Proc. 27, 396–401 (2012)CrossRefGoogle Scholar
  24. 24.
    F. Kersten, A. Schmid, S. Bordihn, J.W. Müller, J. Heitmann, Role of annealing conditions on surface passivation properties of ald \(\text{ Al }_{2}\text{ O }_{3}\) films. Energy Proc. 38, 843–848 (2013)CrossRefGoogle Scholar
  25. 25.
    Y. Zhao, C. Zhou, X. Zhang, P. Zhang, Y. Dou, W. Wang, X. Cao, B. Wang, Y. Tang, S. Zhou, Passivation mechanism of thermal atomic layer-deposited \(\text{ Al }_{2}\text{ O }_{3}\) films on silicon at different annealing temperatures. Nanoscale Res. Lett. 8(1), 114 (2013)ADSCrossRefGoogle Scholar
  26. 26.
    R. Kotipalli, R. Delamare, O. Poncelet, X. Tang, L.A. Francis, D. Flandre, Passivation effects of atomic-layer-deposited aluminum oxide. EPJ Photovol. 4, 45107 (2013)ADSCrossRefGoogle Scholar
  27. 27.
    H. Goverde, B. Vermang, A. Morato, J. John, J. Horzel, G. Meneghesso, J. Poortmans, \(\text{ Al }_{2}\text{ O }_{3}\)surface passivation characterized on hydrophobic and hydrophilic c-Si by a combination of qsspc, cv, xps and ftir. Energy Proc. 27, 355–360 (2012)CrossRefGoogle Scholar
  28. 28.
    M. Li, H.-S. Shin, K.-S. Jeong, S.-K. Oh, H. Lee, K. Han, G.-W. Lee, H.-D. Lee, Blistering induced degradation of thermal stability \(\text{ Al }_{2}\text{ O }_{3}\) passivation layer in crystal Si solar cells. JSTS J. Semicond. Technol. Sci. 14(1), 53–60 (2014)CrossRefGoogle Scholar
  29. 29.
    J. Schmidt, M. Kerr, P.P. Altermatt, Coulomb-enhanced auger recombination in crystalline silicon at intermediate and high injection densities. J. Appl. Phys. 88(3), 1494–1497 (2000)ADSCrossRefGoogle Scholar
  30. 30.
    S. Rein, Lifetime Spectroscopy: A Method of Defect Characterization in Silicon for Photovoltaic Applications, vol. 85 (Springer, Heidelberg, 2006)Google Scholar
  31. 31.
    A. Richter, F. Werner, A. Cuevas, J. Schmidt, S.W. Glunz, Improved parameterization of auger recombination in silicon. Energy Proc. 27, 88–94 (2012)CrossRefGoogle Scholar
  32. 32.
    A. Bansal, H. Mishra, S. Bhattacharya, B.R. Singh, First principles calculations of bonding and charges at the \(\text{ Al }_{2}\text{ O }_{3}\) interface in a \(\text{ c-Si }/\text{ SiO }_{2}\) interface in a \(\text{ c-Si }/\text{ SiO }_{2}/\text{ am-Al }_{2}\text{ O }_{3}\) structure applicable for the surface passivation of silicon-based solar cells. IEEE Trans. Electron Devices 63(2), 544–550 (2016)ADSCrossRefGoogle Scholar
  33. 33.
    B. Hoex, J. Schmidt, P. Pohl, M.C.M. Van de Sanden, W.M.M. Kessels, Silicon surface passivation by atomic layer deposited \(\text{ Al }_{2}\text{ O }_{3}\). J. Appl. Phys. 104(4), 044903 (2008)ADSCrossRefGoogle Scholar
  34. 34.
    F. Werner, B. Veith, D. Zielke, L. Kühnemund, C. Tegenkamp, M. Seibt, J. Schmidt, R. Brendel. Improved understanding of recombination at the Si/\(\text{ Al }_{2}\text{ O }_{3}\)interface. in Proceedings of the 25th European Photovoltaic Solar Energy Conference, Valencia, (2010)Google Scholar
  35. 35.
    A. Stesmans, V.V. Afanas’ev, Electron spin resonance features of interface defects in thermal (100) \({\text{ Si }}/\text{ SiO }_{2}\). J. Appl. Phys. 83(5), 2449–2457 (1998)ADSCrossRefGoogle Scholar
  36. 36.
    S. Bordihn, V. Mertens, J.W. Müller, W.M.M. Kessels, Deposition temperature dependence of material and si surface passivation properties of \(\text{ o }_{3}\)-based atomic layer deposited \(\text{ Al }_{2}\text{ O }_{3}\)-based films and stacks. J. Vac. Sci. Technol. A Vac. Surf. Films 32(1), 01A128 (2014)CrossRefGoogle Scholar
  37. 37.
    G. Dingemans, P. Engelhart, R. Seguin, M.M. Mandoc, M.C.M. van de Sanden, W.M.M. Kessels. Comparison between aluminum oxide surface passivation films deposited with thermal ALD, plasma ALD and PECVD. in Photovoltaic Specialists Conference (PVSC), 2010 35th IEEE dingemans2010comparison, IEEE, (2010) pp. 003118–003121Google Scholar
  38. 38.
    J. Haeberle, K. Henkel, H. Gargouri, F. Naumann, B. Gruska, M. Arens, M. Tallarida, D. Schmeißer, Ellipsometry and xps comparative studies of thermal and plasma enhanced atomic layer deposited \(\text{ Al }_{2}\text{ O }_{3}\)-films. Beilstein J. Nanotechnol. 4(1), 732–742 (2013)CrossRefGoogle Scholar
  39. 39.
    M. Tulio Aguilar-Gama, E. Ramírez-Morales, Z. Montiel-González, A. Mendoza-Galván, M. Sotelo-Lerma, P.K. Nair, H. Hu, Structure and refractive index of thin alumina films grown by atomic layer deposition. J. Mater. Sci. Mater. Electron. 26(8), 5546–5552 (2015)CrossRefGoogle Scholar
  40. 40.
    S.-K. Oh, H.-S. Shin, K.-S. Jeong, M. Li, H. Lee, K. Han, Y. Lee, G.-W. Lee, H.-D. Lee, Process temperature dependence of \(\text{ Al }_{2}\text{ O }_{3}\) film deposited by thermal ald as a passivation layer for c-Si solar cells. JSTS J. Semicond. Technol. Sci. 13(6), 581–588 (2013)CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Akansha Bansal
    • 1
  • Prashant Singh
    • 1
  • Rajesh Kumar Jha
    • 1
    Email author
  • B. R. Singh
    • 1
  1. 1.Department of Electronics and Communication EngineeringIndian Institute of Information TechnologyAllahabadIndia

Personalised recommendations