Applied Microscopy

  • 제50권
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  • Pages.17.1-17.9
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  • 2020
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  • 2287-5123(pISSN)
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  • 2287-4445(eISSN)
한국현미경학회 (Korean Society of Microscopy)
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Depth-dependent EBIC microscopy of radial-junction Si micropillar arrays

  • Kaden M. Powell (Electrical and Computer Engineering, University of Utah) ;
  • Heayoung P. Yoon (Electrical and Computer Engineering, University of Utah)
  • 투고 : 2020.07.15
  • 심사 : 2020.08.24
  • 발행 : 2020.12.31
⟨ 이전 논문 다음 논문 ⟩

초록

Recent advances in fabrication have enabled radial-junction architectures for cost-effective and high-performance optoelectronic devices. Unlike a planar PN junction, a radial-junction geometry maximizes the optical interaction in the three-dimensional (3D) structures, while effectively extracting the generated carriers via the conformal PN junction. In this paper, we report characterizations of radial PN junctions that consist of p-type Si micropillars created by deep reactive-ion etching (DRIE) and an n-type layer formed by phosphorus gas diffusion. We use electron-beam induced current (EBIC) microscopy to access the 3D junction profile from the sidewall of the pillars. Our EBIC images reveal uniform PN junctions conformally constructed on the 3D pillar array. Based on Monte-Carlo simulations and EBIC modeling, we estimate local carrier separation/collection efficiency that reflects the quality of the PN junction. We find the EBIC efficiency of the pillar array increases with the incident electron beam energy, consistent with the EBIC behaviors observed in a high-quality planar PN junction. The magnitude of the EBIC efficiency of our pillar array is about 70% at 10 kV, slightly lower than that of the planar device (≈ 81%). We suggest that this reduction could be attributed to the unpassivated pillar surface and the unintended recombination centers in the pillar cores introduced during the DRIE processes. Our results support that the depth-dependent EBIC approach is ideally suitable for evaluating PN junctions formed on micro/nanostructured semiconductors with various geometry.

키워드

과제정보

The authors acknowledge the support from B. Baker, D. Magginetti, and S. Pritchett for the development of device fabrication. The radial junction processes and the EBIC data acquisition were performed at Penn State University (University Park, PA, USA) and the National Institute of Standards and Technology (Gaithersburg, MD, USA). We thank Y. Yuwen, T. Mayer, P. Haney, and N. Zhitenev for valuable discussions.

참고문헌

  1. Y.H. Chu, C.Q. Qian, P. Chahal, C.Y. Cao, Printed diodes: Materials processing, fabrication, and applications. Adv. Sci. 6(6), 1801653 (2019). https://doi.org/10.1002/advs.201801653
  2. K.M. Dowling, E.H. Ransom, D.G. Senesky, Profile evolution of high aspect ratio silicon carbide trenches by inductive coupled plasma etching. J. Microelectromech. Syst. 26(1), 135-142 (2017). https://doi.org/10.1109/Jmems.2016.2621131
  3. D. Drouin, A.R. Couture, D. Joly, X. Tastet, V. Aimez, R. Gauvin, CASINO V2.42 - a fast and easy-to-use modeling tool for scanning electron microscopy and microanalysis users. Scanning 29(3), 92-101 (2007). https://doi.org/10.1002/sca.20000
  4. E. Garnett, P.D. Yang, Light trapping in silicon nanowire solar cells. Nano Lett. 10(3), 1082-1087 (2010). https://doi.org/10.1021/nl100161z
  5. H. Han, Z.P. Huang, W. Lee, Metal-assisted chemical etching of silicon and nanotechnology applications. Nano Today 9(3), 271-304 (2014). https://doi.org/10.1016/j.nantod.2014.04.013
  6. P.M. Haney, H.P. Yoon, B. Gaury, N.B. Zhitenev, Depletion region surface effects in electron beam induced current measurements. J. Appl. Phys. 120(9), 095702 (2016). https://doi.org/10.1063/1.4962016
  7. Z.P. Huang, N. Geyer, P. Werner, J. de Boor, U. Gosele, Metal-assisted chemical etching of silicon: A review. Adv. Mater. 23(2), 285-308 (2011). https://doi.org/10.1002/adma.201001784
  8. B.M. Kayes, H.A. Atwater, N.S. Lewis, Comparison of the device physics principles of planar and radial p-n junction nanorod solar cells. J. Appl. Phys. 97(11), 114302 (2005). https://doi.org/10.1063/1.1901835
  9. M.D. Kelzenberg, S.W. Boettcher, J.A. Petykiewicz, D.B. Turner-Evans, M.C. Putnam, E.L. Warren, et al., Enhanced absorption and carrier collection in Si wire arrays for photovoltaic applications. Nat. Mater. 9(3), 239 (2010) ://WOS:000274700900021
  10. C.E. Kendrick, H.P. Yoon, Y.A. Yuwen, G.D. Barber, H.T. Shen, T.E. Mallouk, et al., Radial junction silicon wire array solar cells fabricated by gold-catalyzed vapor-liquid-solid growth. Appl. Phys. Lett. 97(14), 143108 (2010). https://doi.org/10.1063/1.3496044
  11. T. Kobayashi, M. Koyama, T. Sugita, S. Takayanagi, Performance of GaAs surfacebarrier detectors made from high-purity gallium-arsenide. IEEE Trans. Nucl. Sci. 19(3), 324-32+ (1972). https://doi.org/10.1109/Tns.1972.4326745
  12. Laermer, F., & Schilp, A. (2003). Method of anisotropic etching of silicon. Patent US6531068 (US)
  13. H.J. Leamy, Charge collection scanning electron-microscopy. J. Appl. Phys. 53(6), R51-R80 (1982). https://doi.org/10.1063/1.331667
  14. K.K. Lew, J.M. Redwing, Growth characteristics of silicon nanowires synthesized by vapor-liquid-solid growth in nanoporous alumina templates. J. Cryst. Growth 254(1-2), 14-22 (2003). https://doi.org/10.1016/S0022-0248(03)01146-1
  15. X.L. Li, Metal assisted chemical etching for high aspect ratio nanostructures: A review of characteristics and applications in photovoltaics. Curr. Opin. Solid State Mater. Sci. 16(2), 71-81 (2012). https://doi.org/10.1016/j.cossms.2011.11.002
  16. G.W. Neudeck, The PN Junction Diode (Addison-Wesley, Reading, 1989)
  17. G.S. Oehrlein, Dry etching damage of silicon - a review. Mater. Sci. Eng. B Solid State Mater. Adv. Technol. 4(1-4), 441-450 (1989). https://doi.org/10.1016/0921-5107(89)90284-5
  18. Qian, Y., Magginetti, D. J., Jeon, S., Yoon, Y., Olsen, T. L., Wang, M., et al. (2020). Heterogeneous optoelectronic characteristics of Si micropillar arrays fabricated by metal-assisted chemical etching. https://ui.adsabs.harvard.edu/abs/2020arXiv200616308Q. Accessed 1 June 2020
  19. D.L. Sengupta, T.K. Sarkar, D. Sen, Centennial of the semiconductor diode detector. Proc. IEEE 86(1), 235-243 (1998). https://doi.org/10.1109/5.658775
  20. C.W. Teplin, S. Grover, A. Chitu, A. Limanov, M. Chahal, J. Im, et al., Comparison of thin epitaxial film silicon photovoltaics fabricated on monocrystalline and polycrystalline seed layers on glass. Prog. Photovolt. 23(7), 909-917 (2015). https://doi.org/10.1002/pip.2505
  21. H.D. Um, N. Kim, K. Lee, I. Hwang, J.H. Seo, Y.J. Yu, et al., Versatile control of metal-assisted chemical etching for vertical silicon microwire arrays and their photovoltaic applications. Sci. Rep. 5, 11277 (2015). https://doi.org/10.1038/srep11277
  22. D.B. Wittry, D.F. Kyser, Measurement of diffusion lengths in direct-gap semiconductors by electron-beam excitation. J. Appl. Phys. 38(1), 375 (1967). https://doi.org/10.1063/1.1708984
  23. B.Q. Wu, A. Kumar, S. Pamarthy, High aspect ratio silicon etch: A review. J. Appl. Phys. 108(5), 051101 (2010). https://doi.org/10.1063/1.3474652
  24. C.J. Wu, D.B. Wittry, Investigation of minority-carrier diffusion lengths by electron-bombardment of Schottky barriers. J. Appl. Phys. 49(5), 2827-2836 (1978). https://doi.org/10.1063/1.325163
  25. E.B. Yakimov, What is the real value of diffusion length in GaN? J. Alloys Compd. 627, 344-351 (2015). https://doi.org/10.1016/j.jallcom.2014.11.229
  26. J. Yoo, S.A. Dayeh, W. Tang, S.T. Picraux, Epitaxial growth of radial Si p-i-n junctions for photovoltaic applications. Appl. Phys. Lett. 102(9), 093113 (2013). https://doi.org/10.1063/1.4794541
  27. H.P. Yoon, P.M. Haney, J. Schumacher, K. Siebein, Y. Yoon, N.B. Zhitenev, Effects of focused-ion-beam processing on local electrical measurements of inorganic solar cells. Microsc. Microanal. 20(S3), 544-545 (2014). https://doi.org/10.1017/S1431927614004449
  28. H.P. Yoon, Y.A. Yuwen, C.E. Kendrick, G.D. Barber, N.J. Podraza, J.M. Redwing, et al., Enhanced conversion efficiencies for pillar array solar cells fabricated from crystalline silicon with short minority carrier diffusion lengths. Appl. Phys. Lett. 96(21), 213503 (2010). https://doi.org/10.1063/1.3432449
  29. H.P. Yoon, Y.A. Yuwen, H. Shen, N.J. Podraza, T.E. Mallouk, E.C. Dickey, et al., in 37th IEEE Photovoltaic Specialists Conference. Parametric study of micropillar array solar cells (2011), pp. 000303-000306. https://doi.org/10.1109/PVSC.2011.6185905
  30. A. Zeniou, K. Ellinas, A. Olziersky, E. Gogolides, Ultra-high aspect ratio Si nanowires fabricated with plasma etching: Plasma processing, mechanical stability analysis against adhesion and capillary forces and oleophobicity. Nanotechnology 25(3), 035302 (2014). https://doi.org/10.1088/0957-4484/25/3/035302
  31. R.N. Zhou, M.Z. Yu, D. Tweddle, P. Hamer, D. Chen, B. Hallam, et al., Understanding and optimizing EBIC pn-junction characterization from modeling insights. J. Appl. Phys. 127(2), 024502 (2020). https://doi.org/10.1063/1.5139894