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Self-patterned localized metal contacts for silicon solar cells

  • Zhong Lu (a1), Pei Hsuan Lu (a1), Jie Cui (a1), Kai Wang (a1) and Alison Lennon (a1)...

Abstract

This paper describes the use of self-patterning anodic aluminum oxide (AAO) layers to enable localized metal contacts and to achieve passivation for the rear surface of silicon solar cells. There are no commercially available technologies that are capable of patterning localized contacts on silicon solar cells with low cost, high-throughput, and robust processing, especially when closely spaced small-area openings are required. In the approach described, nanoporous AAO layers were formed by anodizing aluminum over intervening dielectrics on textured silicon wafers. When the anodized test structures were fired in a belt furnace, localized contacts formed at peaks and valleys of the alkaline-textured silicon surface. Furthermore, the anodization contributed ∼35 mV increment in the implied Voc of the test structures. Low contact resistivity was demonstrated and the proposed contacting mechanism for this innovative localization suggested that the contact percentage can be controlled by varying the anodization duration and/or the surface morphology.

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Corresponding author

a)Address all correspondence to this author. e-mail: z.lu@student.unsw.edu.au

References

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1.Zhao, J., Wang, A., and Green, M.A.: 24.5% efficiency silicon PERT cells on MCZ substrates and 24.7% efficiency PERL cells on FZ substrates. Prog. Photovoltaics Res. Appl. 7(6), 471474 (1999).
2.Swanson, R.M., Beckwith, S.K., Crane, R.A., Eades, W.D., Young Hoon, K., Sinton, R.A., and Swirhun, S.E.: Point-contact silicon solar cells. IEEE Trans. Electron Devices 31(5), 661664 (1984).
3.Muller, J., Bothe, K., Gatz, S., Plagwitz, H., Schubert, G., and Brendel, R.: Contact formation and recombination at screen-printed local aluminum-alloyed silicon solar cell base contacts. IEEE Trans. Electron Devices 58(10), 32393245 (2011).
4.Jiun-Hong, L., Upadhyaya, A., Ramanathan, S., Das, A., Tate, K., Upadhyaya, V., Kapoor, A., Chia-Wei, C., and Rohatgi, A.: High-efficiency large-area rear passivated silicon solar cells with local Al-BSF and screen-printed contacts. IEEE J. Photovoltaics 1, 1621 (2011).
5.Wang, Z., Han, P., Lu, H., Qian, H., Chen, L., Meng, Q., Tang, N., Gao, F., Jiang, Y., Wu, J., Wu, W., Zhu, H., Ji, J., Shi, Z., Sugianto, A., Mai, L., Hallam, B., and Wenham, S.: Advanced PERC and PERL production cells with 20.3% record efficiency for standard commercial p-type silicon wafers. Prog. Photovoltaics Res. Appl. 20(3), 260268 (2012).
6.Dullweber, T., Gatz, S., Hannebauer, H., Falcon, T., Hesse, R., Schmidt, J., and Brendel, R.: Towards 20% efficient large-area screen-printed rear-passivated silicon solar cells. Prog. Photovoltaics Res. Appl. 20(6) 630638 (2011).
7.Gatz, S., Hannebauer, H., Hesse, R., Werner, F., Schmidt, A., Dullweber, T., Schmidt, J., Bothe, K., and Brendel, R.: 19.4%-efficient large-area fully screen-printed silicon solar cells. Phys. Status Solidi RRL 5(4), 147149 (2011).
8.Schmidt, J., Merkle, A., Brendel, R., Hoex, B., de Sanden, M.C.M., and Kessels, W.M.M.: Surface passivation of high-efficiency silicon solar cells by atomic-layer-deposited Al2O3. Prog. Photovoltaics Res. Appl. 16(6), 461466 (2008).
9.Zhao, J., Wang, A., and Green, M.A.: Series resistance caused by localised rear contact in high efficiency solar cells. Sol. Energy Mater. Sol. Cells 32(1), 8994 (1994).
10.Wenham, S.R., Chan, B.O., Honsberg, C.B., and Green, M.A.: Beneficial and constraining effects of laser scribing in buried-contact solar cells. Prog. Photovoltaics Res. Appl. 5(2), 131137 (1997).
11.Junge, J.: Laser fired contacts for high efficiency solar cells based on EFG material. In 23rd European Photovoltaic Solar Energy Conference and Exhibition, Valencia, Spain, 2008. (WIP-Munich, München, Germany, 2008).
12.Lennon, A., Utama, R., Lenio, M., Ho-Baillie, A., Kuepper, N., and Wenham, S.R.: Forming openings to semiconductor layers of silicon solar cells by inkjet printing. Sol. Energy Mater. Sol. Cells 92(11), 14101415 (2008).
13.Lenio, M., Howard, J., Jentschke, F., Lennon, A., and Wenham, S.R.: Design, fabrication and analysis of high efficiency inkjet printed passivated emitter rear contacted cells. In 37th IEEE Photovoltaic Specialists Conference, Seattle, WA, 19–24 June, 2011, Seattle, WA, 2011. (IEEE, Austin, TX, 2011).
14.Lennon, A., Renn, M., King, B., and Wenham, S.R.: Aerosol jet etching for silicon solar cells. In 24th European Photovoltaic Solar Energy Conference, Hamburg, Germany, 21–25 September, 2009; Hamburg, Germany, 2009; pp. 22462249. (WIP-Munich, München, Germany, 2009).
15.Rodriguez, J., Lennon, A., Mei, H., Chan, C., Lu, P.H., Yao, Y., and Wenham, S.R.: Direct etching - targeting commercial photovoltaic applications. In Digital Fabrication Conference, Minneapolis, MN, 2–6 October 2011; Minneapolis, MN, 2011. (The Society for Imaging Science and Technology, 2011).
16.Liu, L., Du, Z., Lin, F., Hoex, B., and Aberle, A.G.: Aluminum local back surface field solar cells with inkjet-opened rear dielectric films. In 38th IEEE Photovoltaics Specialist Conference, Austin, TX, 3–8 June, 2012; Austin, TX, 2012. (IEEE, Austin, TX, 2012).
17.Urrejola, E., Peter, K., Plagwitz, H., and Schubert, G.: Al-Si alloy formation in narrow p-type Si contact areas for rear passivated solar cells. J. Appl. Phys. 107(12), 124516 (2010).
18.Grasso, F.S., Gautero, L., Rentsch, J., Preu, R., and Lanzafame, R.: Characterisation of local AL-BSF formation for PERC solar cell. In 25th European Photovoltaic Solar Energy Conference and Exhibition, Valencia, Spain, 6–10 September, 2010; Valencia, Spain, 2010; pp. 371374. (WIP-Munich, München, Germany, 2010).
19.Diggle, J.W., Downie, T.C., and Goulding, C.W.: Anodic oxide films on aluminum. Chem. Rev. 69(3), 365405 (1969).
20.Lee, W., Scholz, R., Nielsch, K., and Gösele, U.: A template-based electrochemical method for the synthesis of multisegmented metallic nanotubes. Angew. Chem. Int. Ed. 44(37), 60506054 (2005).
21.Mikulskas, I., Juodkazis, S., Tomasiunas, R., and Dumas, J.G.: Aluminum oxide photonic crystals grown by a new hybrid method. Adv. Mater. 13(20), 15741577 (2001).
22.Lu, P.H., Wang, K., Lu, Z., Lennon, A., and Wenham, S.: Anodic aluminum oxide passivation for silicon solar cells. In IEEE J. Photovoltaics. (IEEE, Austin, TX, 2012).
23.Lu, P.H.D., Chen, Y., and Lennon, A.: Innovative rear point-contact scheme for silicon solar cells. In Solar 2010 Conference, Canberra, Australia, 2010; Canberra, Australia, 2010. (Australian Solar Energy Society, 2010).
24.Lee, W., Nielsch, K., and Gosele, U.: Self-ordering behavior of nanoporous anodic aluminum oxide (AAO) in malonic acid anodization. Nanotechnology 18, 475713475721 (2007).
25.Narasimha, S. and Rohatgi, A.: An optimized rapid aluminum back surface field technique for silicon solar cells. IEEE Trans. Electron Devices 46(7), 13631370 (1999).
26.Sinton, R.A., Cuevas, A., and Stuckings, M.: Quasi-steady-state photoconductance, a new method for solar cell material and device characterization. In 25th IEEE Photovoltaic Specialists Conference, Washington, DC, 13–17 May, 1996; Washington, DC, 1996; pp. 457460. (IEEE, Austin, TX, 1996).
27.Sproul, A.B. and Green, M.A.: Improved value for the silicon intrinsic carrier concentration from 275 to 375 K. J. Appl. Phys. 70, 846854 (1991).
28.Raineri, V., Privitera, V., Vandervorst, W., Hellemans, L., and Snauwaert, J.: Carrier distribution in silicon devices by atomic force microscopy on etched surfaces. Appl. Phys. Lett. 64(3), 354356 (1994).
29.Berger, H.H.: Models for contacts to planar devices. Solid State Electron. 15, 145158 (1972).
30.Schroder, D.K. and Meier, D.L.: Solar cell contact resistance - a review. IEEE Trans. Electron Devices ED- 31(5), 637647 (1984).
31.Hezel, R. and Jaeger, K.: Low-temperature surface passivation of silicon for solar cells. J. Electrochem. Soc. 136(2), 518523 (1989).
32.Hoex, B., Heil, S.B.S., Langereis, E., van de Sanden, M.C.M., and Kessels, W.M.M.: Ultralow surface recombination of c-Si substrates passivated by plasma-assisted atomic layer deposited Al2O3. Appl. Phys. Lett. 89, 042112042114 (2006).
33.Schmidt, J., Merkle, A., Hoex, B., van de Sanden, M.C.M., and Kessels, W.M.M.: Atomic-layer-deposited aluminum oxide for the surface passivation of high efficiency silicon solar cells. In 33rd IEEE Photovoltaics Specialist Conference, San Diego, CA, 11–16 May, 2008; San Diego, CA, 2008.
34.Lambert, J., Guthmann, C., Ortega, C., and Saint-Jean, M.: Permanent polarization and charge injection in thin anodic alumina layers studied by electrostatic force microscopy. J. Appl. Phys. 91(11), 91619169 (2002).
35.Vrublevsky, I., Jagminas, A., Schreckenbach, J., and Goedel, W.A.: Electronic properties of electrolyte/anodic alumina junction during porous anodizing. Appl. Surf. Sci. 253(10), 46804687 (2007).
36.Williams, K.R., Gupta, K., and Waslik, M.: Etch rates for micromachining processing - part 2. J. Microelectromech. Syst. 12, 761778 (2003).
37.Ximello-Quiebras, N., Dastgheib-Shirazi, A., Scholz, S., and Hahn, G.: Influence of pyramid size of chemically textured silicon wafers on the characteristics of industrial solar cells. In 25th European Photovoltaic Solar Energy Conference and Exhibition, Valencia, Spain, 6–10 September, 2010; Valencia, Spain, 2010; pp. 17611764.
38.Cudzinovic, M.J. and Sopori, B.: Control of back surface reflectance from aluminum alloyed contacts on silicon solar cells. In 25th IEEE Photovoltaics Specialist Conference, 1996; 1996; pp 501503.
39.Meemongkolkiat, V., Nakayashiki, K., Kim, D.S., Kopecek, R., and Rohatgi, A.: Factors limiting the formation of uniform and thick aluminum–back-surface field and its potential. J. Electrochem. Soc. 153(1), G53G58 (2006).
40.Muller, J., Gatz, S., Bothe, K., and Brendel, R.: Optimizing the geometry of local aluminum-alloyed contacts to fully screen-printed silicon solar cells. In Photovoltaic Specialists Conference (PVSC), 2012 38th IEEE, 3–8 June 2012, 2012; pp. 002223002228.
41.Dauwe, S., Mittelstädt, L., Metz, A., and Hezel, R.: Experimental evidence of parasitic shunting in silicon nitride rear surface passivated solar cells. Prog. Photovoltaics Res. Appl. 10(4), 271278 (2002).
43.Cui, J., Colwell, J., Li, Z., and Lennon, A.: Localised back surface field formation via different dielectric patterning approaches. In The 50th Annual Australian Solar Council's Conference. Swinburne University of Technology, Melbourne, (AuSES, 2012).

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