Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-28T14:40:19.147Z Has data issue: false hasContentIssue false
  • English
  • Français

Kerfless exfoliated thin crystalline Si wafers with Al metallization layers for solar cells

Published online by Cambridge University Press:  10 November 2015

Raphael Niepelt ,
Jan Hensen ,
Verena Steckenreiter ,
Rolf Brendel  and
Sarah Kajari-Schöder
Raphael Niepelt*
Affiliation:
Department of Photovoltaics, Institute for Solar Energy Research Hamelin (ISFH), D-31860 Emmerthal, Germany
Jan Hensen
Affiliation:
Department of Photovoltaics, Institute for Solar Energy Research Hamelin (ISFH), D-31860 Emmerthal, Germany
Verena Steckenreiter
Affiliation:
Department of Photovoltaics, Institute for Solar Energy Research Hamelin (ISFH), D-31860 Emmerthal, Germany
Rolf Brendel
Affiliation:
Department of Photovoltaics, Institute for Solar Energy Research Hamelin (ISFH), D-31860 Emmerthal, Germany; and Institut für Festkörperphysik, Leibniz Universität Hannover, D-30167 Hannover, Germany
Sarah Kajari-Schöder
Affiliation:
Department of Photovoltaics, Institute for Solar Energy Research Hamelin (ISFH), D-31860 Emmerthal, Germany
*
a)Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

We report on a kerfless exfoliation approach to further reduce the costs of crystalline silicon photovoltaics making use of evaporated Al as a double functional layer. The Al serves as the stress inducing element to drive the exfoliation process and can be maintained as a rear contacting layer in the solar cell after exfoliation. The 50–70 µm thick exfoliated Si layers show effective minority carrier lifetimes around 180 µs with diffusion lengths of 10 times the layer thickness. We analyze the thermo-mechanical properties of the Al layer by x-ray diffraction analysis and investigate its influence on the exfoliation process. We evaluate the approach for the implementation into solar cell production by determining processing limits and estimating cost advantages of a possible solar cell design route. The Al–Si bilayers are mechanically stable under processing conditions and exhibit a moderate cost savings potential of 3–36% compared to other c-Si cell concepts.

Keywords

Six-ray diffraction (XRD)thermal stresses
Type
Invited Feature Paper
Information
Journal of Materials Research , Volume 30 , Issue 21 , 13 November 2015 , pp. 3227 - 3240
Copyright
Copyright © Materials Research Society 2015 

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.)

Footnotes

Contributing Editor: Don W. Shaw

This paper has been selected as an Invited Feature Paper.

References

REFERENCES

International Technology Roadmap for Photovoltaic (ITRPV) (SEMI PV GROUP, Berlin, Germany, 2015) www.itrpv.net (accessed May 25, 2015).Google Scholar
Yisng, C.: Energy Trend PV (2014) http://pv.energytrend.com/price/20140103-6007.html (accessed January 7, 2014).Google Scholar
Bruel, M.: Silicon on insulator material technology. Electron. Lett. 31(14), 1201 (1995).Google Scholar
Henley, F., Kang, S., Liu, Z., Tian, L., Wang, J., and Chow, Y-L.: Beam-induced wafering technology for kerf-free thin PV manufacturing. Presented at the 34th IEEE Photovoltaic Specialists Conference, Philadelphia, 2009; p. 1718.Google Scholar
Brendel, R. and Ernst, M.: Macroporous Si as an absorber for thin-film solar cells. Phys. Status Solidi RRL 4(1–2), 40 (2010).Google Scholar
Brendel, R.: A novel process for ultrathin monocrystalline silicon solar cells on glass. Presented at the 14th European Photovoltaic Solar Energy Conference, Barcelona, Spain, 1997; p. 1354.Google Scholar
Hayes, G.J. and Clemens, B.M.: Rapid lift-off of epitaxial thin films. J. Mater. Res. 28(18), 2564 (2013).Google Scholar
Tanielian, M., Blackstone, S., and Lajos, R.: A new technique of forming thin free standing single-crystal films. J. Electrochem. Soc. 132(2), 508 (1985).Google Scholar
Dross, F., Robbelein, J., Vandevelde, B., van Kerschaver, E., Gordon, I., Beaucarne, G., and Poortmans, J.: Stress-induced large-area lift-off of crystalline Si films. Appl. Phys. A 89(1), 149 (2007).Google Scholar
Bedell, S.W., Shahrjerdi, D., Hekmatshoar, B., Fogel, K., Lauro, P., Ott, J.A., Sosa Cortes, N.E., and Sadana, D.: Kerf-less removal of Si, Ge, and III–V layers by controlled spalling to enable low-cost PV technologies. IEEE J. Photovoltaics 2(2), 141 (2012).Google Scholar
Bedell, S.W., Fogel, K., Lauro, P., Shahrjerdi, D., Ott, J.A., and Sadana, D.: Layer transfer by controlled spalling. J. Phys. D: Appl. Phys. 46(15), 152002 (2013).Google Scholar
Rao, R.A., Mathew, L., Saha, S., Smith, S., Sarkar, D., Garcia, R., Stout, R., and Gurmu, A.: A novel low cost 25 µm thin exfoliated monocrystalline Si solar cell technology. Presented at the 37th IEEE Photovoltaic Specialists Conference, Seattle, 2011; p. 1504.Google Scholar
Kwon, Y., Yang, C., Yoon, S-H., Um, H-D., Lee, J-H., and Yoo, B.: Spalling of a thin Si layer by electrodeposit-assisted stripping. Appl. Phys. Express 6(11), 116502 (2013).Google Scholar
Suo, Z. and Hutchinson, J.W.: Steady-state cracking in brittle substrates beneath adherent films. Int. J. Solids Struct. 25(11), 1337 (1989).Google Scholar
Rao, R.A., Mathew, L., Sarkar, D., Smith, S., Saha, S., Garcia, R., Stout, R., Gurmu, A., and Ainom, M.: A low cost kerfless thin crystalline Si solar cell technology. Presented at the 38th IEEE Photovoltaic Specialists Conference, Austin, 2012; p. 1837.Google Scholar
Masolin, A., Simoen, E., Kepa, J., and Stesmans, A.: Defects in Si foils fabricated by spalling at low temperature: Electrical activity and atomic nature. J. Phys. D: Appl. Phys. 46(15), 155501 (2013).Google Scholar
Martini, R., Kepa, J., Debucquoy, M., Depauw, V., Gonzalez, M., Gordon, I., Stesmans, A., and Poortmans, J.: Thin silicon foils produced by epoxy-induced spalling of silicon for high efficiency solar cells. Appl. Phys. Lett. 105(17), 173906 (2014).Google Scholar
Sinton, R.A.: Quasi-steady-state photoconductance, a new method for solar cell material and device characterization. Presented at the 25th IEEE Photovoltaic Specialists Conference, Washington, D.C., 1996; p. 457.Google Scholar
Saha, S., Hilali, M.M., Onyegam, E.U., Sarkar, D., Jawarani, D., Rao, R.A., Mathew, L., Smith, R.S., Xu, D., Das, U.K., Sopori, B., and Banerjee, S.K.: Single heterojunction solar cells on exfoliated flexible ∼25 μm thick mono-crystalline silicon substrates. Appl. Phys. Lett. 102(16), 163904 (2013).Google Scholar
Schönfelder, S., Breitenstein, O., Rissland, S., de Donno, R., and Bagdahn, J.: Glue-cleave: Kerfless wafering for silicon wafers with metal gluing and removable interface. In Proceedings of the 22nd Workshop on Crystalline Silicon Solar Cells & Modules: Materials and Processes, Sopori, B. and Sinton, R. ed.; Golden: Vail, CO, 2012; p. 208.Google Scholar
Bellanger, P., Brito, M.C., Pera, D., Costa, I., Gaspar, G., Martini, R., Debucquoy, M., and Serra, J.M.: New stress activation method for kerfless silicon wafering using Ag/Al and epoxy stress-inducing layers. IEEE J. Photovoltaics 4(5), 1228 (2014).Google Scholar
Hatch, J.E.: Aluminum: Properties and Physical Metallurgy (ASM International, Russel, OH, 1984); p. 6.Google Scholar
Masolin, A., Bouchard, P-O., Martini, R., and Bernacki, M.: Thermo-mechanical and fracture properties in single-crystal silicon. J. Mater. Sci. 48(3), 979 (2013).Google Scholar
Hensen, J., Niepelt, R., Kajari-Schroder, S., and Brendel, R.: Directional heating and cooling for controlled spalling. IEEE J. Photovoltaics 5(1), 195 (2015).Google Scholar
Heinemeyer, F., Mader, C., Münster, D., Dullweber, T., Harder, N.P., and Brendel, R.: In-line high-rate thermal evaporation of aluminium as a novel industrial solar cell metallization scheme. In Proceedings of the 2nd Workshop on Metallization for Crystalline Silicon Solar Cells, Hoornsta, J., Schubert, G., and Beaucarne, G. ed.; University of Konstanz: Konstanz, Germany, 2010; p. 48.Google Scholar
Niepelt, R., Hensen, J., Knorr, A., Steckenreiter, V., Kajari-Schröder, S., and Brendel, R.: High-quality exfoliated crystalline silicon foils for solar cell applications. Energy Procedia 55, 570 (2014).Google Scholar
Kajari-Schröder, S., Hensen, J., Niepelt, R., and Brendel, R.: Kerfless wafering by mechanically induced spallation—Observation of the process evolution with digital image correlation. Presented at the 6th World Conference on Photovoltaic Energy Conversion, Kyoto, Japan, 2014; p. J1ThO.7.3.Google Scholar
Ramspeck, K., Bothe, K., Schmidt, J., and Brendel, R.: Combined dynamic and steady-state infrared camera based carrier lifetime imaging of silicon wafers. J. Appl. Phys. 106(11), 114506 (2009).Google Scholar
Schlangenotto, H., Maeder, H., and Gerlach, W.: Temperature dependence of the radiative recombination coefficient in silicon. Phys. Status Solidi A 21(1), 357 (1974).Google Scholar
Richter, A., Glunz, S.W., Werner, F., Schmidt, J., and Cuevas, A.: Improved quantitative description of Auger recombination in crystalline silicon. Phys. Rev. B 86(16), 5202 (2012).Google Scholar
Macherauch, E. and Müller, P.: Zur Eigenspannungsausbildung bei einer Al-Legierung und bei Reinstaluminium. Naturwissenschaften 44(14), 389 (1957).CrossRefGoogle Scholar
Gere, J.M.: Mechanics of Materials, 6th ed. (Brooks/Cole, Belmont, CA, 2004).Google Scholar
Evans, A.G. and Hutchinson, J.W.: The thermomechanical integrity of thin films and multilayers. Acta Metall. Mater. 43(7), 2507 (1995).Google Scholar
Shi, H., McLaren, A.J., Sellars, C.M., Shahani, R., and Bolingbroke, R.: Constitutive equations for high temperature flow stress of aluminium alloys. Mater. Sci. Technol. 13, 210 (1997).Google Scholar
Bauser, M., Sauer, G., and Siegert, K.: Extrusion, 2nd ed. (ASM International, Russel, OH, 2006).Google Scholar
Bader, S., Kalaugher, E.M., and Arzt, E.: Comparison of mechanical properties and microstructure of Al(1 wt.%Si) and Al(1 wt.%Si, 0.5 wt.%Cu) thin films. Thin Solid Films 263(2), 175 (1995).Google Scholar
Kerr, M., Campbell, P., and Cuevas, A.: Lifetime and efficiency limits of crystalline silicon solar cells. Presented at the 29th IEEE Photovoltaic Specialists Conference, New Orleans, 2002; p. 438.Google Scholar
Richter, A., Hermle, M., and Glunz, S.W.: Reassessment of the limiting efficiency for crystalline silicon solar cells. IEEE J. Photovoltaics 3(4), 1184 (2013).Google Scholar
Brendel, R., Petermann, J.H., Zielke, D., Schulte-Huxel, H., Kessler, M., Gatz, S., Eidelloth, S., Bock, R., Garralaga Rojas, E., Schmidt, J., and Dullweber, T.: High-efficiency cells from layer transfer: A first step toward thin-film/wafer hybrid silicon technologies. IEEE J. Photovoltaics 1(1), 9 (2011).Google Scholar
Petermann, J.H., Schulte-Huxel, H., Steckenreiter, V., Kajari-Schroder, S., and Brendel, R.: Principle of module-level processing demonstrated at single a-Si:H/c-Si heterojunction solar cells. IEEE J. Photovoltaics 4(4), 1018 (2014).Google Scholar
Govaerts, J., Robbelein, J., Gonzalez, M., Gordon, I., Baert, K., de Wolf, I., Bossuyt, F., van Put, S., and Vanfleteren, J.: Developing an advanced module for back-contact solar cells. IEEE Trans. Compon., Packag., Manuf. Technol. 1(3), 1319 (2011).Google Scholar
Kim, J.C. and Cheong, S.K.: I–V curve characteristics of solar cells on composite substrate unsder mechanical loading. J. Mech. Sci. Technol. 28(5), 1691 (2014).Google Scholar
Xu, D., Ho, P.S., Rao, R.A., Mathew, L., Smith, S., Saha, S., Sarkar, D., Vass, C., and Jawarani, D.: Mechanical strength and reliability of a novel thin monocrystalline silicon solar cell. Presented at the IEEE International Reliability Physics Symposium, Anaheim, 2012; p. 4A.3.1.Google Scholar
Tvergaard, V. and Hutchinson, J.W.: Toughness of an interface along a thin ductile layer joining elastic solids. Philos. Mag. A 70(4), 641 (1994).Google Scholar
Volinsky, A., Moody, N., and Gerberich, W.: Interfacial toughness measurements for thin films on substrates. Acta Mater. 50(3), 441 (2002).Google Scholar
Wei, Y. and Hutchinson, J.W.: Nonlinear delamination mechanics for thin films. J. Mech. Phys. Solids 45(7), 1137 (1997).Google Scholar
Hu, Y.Y. and Huang, W.M.: Elastic and elastic-plastic analysis of multilayer thin films: Closed-form solutions. J. Appl. Phys. 96(8), 4154 (2004).Google Scholar
Goodrich, A., Hacke, P., Wang, Q., Sopori, B., Margolis, R., James, T.L., and Woodhouse, M.: A wafer-based monocrystalline silicon photovoltaics road map: Utilizing known technology improvement opportunities for further reductions in manufacturing costs. Sol. Energy Mater. Sol. Cells 114, 110 (2013).Google Scholar
Bellanger, P., Bouchard, P-O., Bernacki, M., and Serra, J.: Room temperature thin foil SLIM-cut using an epoxy paste: Experimental versus theoretical results. Mater. Res. Express 2(4), 046203 (2015).Google Scholar
Steckenreiter, V., Horbelt, R., Wright, D.N., Nese, M., and Brendel, R.: Qualification of encapsulation materials for module-level-processing. Sol. Energy Mater. Sol. Cells 120, 396–401 (2014).Google Scholar
Masolin, A.: Fabrication and characterization of ultra-thin silicon crystalline wafers for photovoltaic applications using a stress-induced lift-off method. Ph.D. Thesis, KU Leuven, Faculty of Engineering, Leuven, BE, 2012.Google Scholar