Effect of current density on silicon surface in electrochemical etching

Norhafizah Burham; Azrul Azlan Hamzah; Burhanuddin Yeop Majlis

Effect of current density on silicon surface in electrochemical etching

View Fulltext

Author(s): Norhafizah Burham ^{1, 2} ; Azrul Azlan Hamzah ¹ ; Burhanuddin Yeop Majlis ¹
- Affiliations: 1: Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), 43650 Bangi, Malaysia;
  2: Faculty of Electrical Engineering, Universiti Teknologi Mara (UiTM), 40450 Shah Alam, Selangor Darul Ehsan, Malaysia
Source: Volume 9, Issue 12, December 2014, p. 850 – 853
DOI: 10.1049/mnl.2014.0382 , Online ISSN 1750-0443

Received 30/06/2014, Accepted 29/08/2014, Published 06/10/2014

A simple and reliable fabrication technique for producing nanoporous filters is presented. The nanoporous filter plays an important role in biomedical microelectromechanical systems applications, especially in filtering out waste and solute from inside human blood. Nanosized components in the biological fluid are filtered using silicon membranes that are controlled by nanosized pores. The technique explored was the electrochemical etching (ECE) process of silicon. This approach starts with thinning the bulk silicon until only several micrometres thick using the KOH process and then carry out ECE to produce pores. The yield of the process was a 3 µm thick nanoporous silicon membrane with pore sizes of less than 100 nm. This physical characteristic enables the membrane to filter all the waste and solute particles of less than 100 nm. Owing to this simple and reliable method, the development of nanoporous silicon membrane can be used in nanofiltration applications especially in an artificial kidney.

References

1. 1)
  - 22. Lehmann, V.: ‘Electrochemistry of silicon: instrumentation, science, materials and applications’ (Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 2002).
2. 2)
  - 17. Li, Z., Zhao, L., Diao, H., Zhou, C., Li, H., Wang, W.: ‘Macroporous silicon formation on low resistivity p-type c-Si substrate by metal catalyzed electrochemical etching’, Int. J. Electrochem. Sci., 2013, 8, pp. 1163–1169.
3. 3)
  - 18. Kang, C.-G., Kang, M.-S., Yang, J.-H., Jin, J.-H., Hong, S.-I., Min, N.-K.: ‘Comparison of nano-porous silicon prepared by photoelectrochemical etching in HF-ethanol and HF-acetonitrile solutions’, J. Korea Phys. Soc., 2003, 42, pp. S693–S697.
4. 4)
  - 14. Kumar, P., Huber, P.: ‘Effect of etching parameter on pore size and porosity of electrochemically formed nanoporous silicon’, J. Nanomater., 2007, 2007, p. 4.
5. 5)
  - 3. Beale, M.I.J., Benjamin, J.D., Uren, M.J., Chew, N.G., Cullis, A.G.: ‘An experimental and theoretical study of the formation and microstructure of porous silicon’, J. Crystal Growth, 1985, 73, (3), pp. 622–636 (doi: 10.1016/0022-0248(85)90029-6).
6. 6)
  - R.L. Smith , S.D. Collins . Porous silicon formation mechanisms. J. Appl. Phys. , R1 - R22
7. 7)
  - 2. Theunissen, M.J.J.: ‘Etch channel formation during anodic dissolution of N-type silicon in aqueous hydrofluoric acid’, J. Electrochem. Soc., 1972, 119, (3), pp. 351–360 (doi: 10.1149/1.2404201).
8. 8)
  - 13. Kumar, P., Lemmens, P., Ghosh, M., Ludwig, F., Schilling, M.: ‘Effect of HF concentration on physical and electronic properties of electrochemically formed nanoporous silicon’, J. Nanomater., 2009, 2009, p. 7.
9. 9)
  - 12. Mehra, R.M., Agarwal, V., Jain, V.K., Mathur, P.C.: ‘Influence of anodisation time, current density and electrolyte concentration on the photoconductivity spectra of porous silicon’, Thin Solid Films, 1997, 315, pp. 281–285 (doi: 10.1016/S0040-6090(97)00756-6).
10. 10)
  - 6. Lehmann, V., Gosele, U.: ‘Porous silicon formation: a quantam wire effect’, Appl. Phys. Lett., 1991, 58, p. 856 (doi: 10.1063/1.104512).
11. 11)
  - 27. Kumar, P., Hofmann, T., Knorr, K., Huber, P., Scheib, P., Lemmens, P.: ‘Tuning the pore wall morphology of mesoporous silicon from branchy to smooth, tubular by chemical treatment’, J. Appl. Phys., 2008, 103, (2), p. 024303 (doi: 10.1063/1.2829813).
12. 12)
  - 4. Lehmann, V., Foll, H.: ‘Formation mechanism and properties of electrochemically etched trenches in n-type silicon’, J. Electrochem. Soc., 1990, 137, (2), pp. 653–659 (doi: 10.1149/1.2086525).
13. 13)
  - 11. Yaakob, S., Ismail, M.A.B., Bakar, N.H.H.A., Ibrahim, K.: ‘The formation and morphology of highly doped N-type porous silicon: effect of short etching time at high current density and evidence of simultaneous chemical and electrochemical dissolutions’, J. Phys. Sci., 2012, 23, (2), pp. 17–31.
14. 14)
  - 15. Canham, L.T.: ‘Properties of porous silicon’ (INSPEC, The Institution of Electrical Engineers, 1997).
15. 15)
  - 16. Lehmann, V.: ‘The physics of macoporous silicon formation’, Thin Solid Films, 1995, 255, pp. 1–4 (doi: 10.1016/0040-6090(94)05620-S).
16. 16)
  - 4. Gaspard, F., Bsiesy, A., Ligeon, M., Muller, F., Herino, R.: ‘Charge exchange mechanism responsible for P-type silicon dissolution during porous silicon formation’, J. Electrochem. Soc., 1989, 136, (10), pp. 3043–3046 (doi: 10.1149/1.2096399).
17. 17)
  - 21. Dittrich, T., Rauscher, S., Timoshenko, V.Y., et al: ‘Ultrathin luminescent nanoporous silicon on n-Si: pH dependent preparation in aqueous NH4F solutions’, Appl. Phys. Lett., 1995, 67, (8), pp. 1134–1136 (doi: 10.1063/1.114985).
18. 18)
  - 7. Zhang, X.G.: ‘Mechanism of pore formation on n-type silicon’, J. Electrochem. Soc., 1991, 138, pp. 3750–3756 (doi: 10.1149/1.2085494).
19. 19)
  - 20. Salonen, J., Lehto, V.P.: ‘Fabrication and chemical surface modification of mesoporous silicon for biomedical applications’, Chem. Eng. J., 2008, 137, (1), pp. 162–172 (doi: 10.1016/j.cej.2007.09.001).
20. 20)
  - 24. Sailor, M.J.: ‘Fundamentals of porous silicon preparation: porous silicon in practice: preparation, characterization and applications’ (Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 2012), pp. 1–42.
21. 21)
  - 25. Chuang, S.F., Collins, S., Smith, R.: ‘Preferential propagation of pores during the formation of porous silicon: a transmission electron microscopy study’, Appl. Phys. Lett., 1989, 55, (7), pp. 675–677 (doi: 10.1063/1.101819).
22. 22)
  - 19. Hamzah, A.A., Abidin, H.E.Z., Majlis, B.Y., et al: ‘Electrochemically deposited and etched membranes with precisely sized micropores for biological fluids microfiltration’, J. Micromech. Microeng., 2013, 23, pp. 836–840.
23. 23)
  - 1. Lehmann, V.: ‘The physics of macropore formation in low doped n-type silicon’, J. Electrochem. Soc., 1993, 140, (10), pp. 2836–2843 (doi: 10.1149/1.2220919).
24. 24)
  - 10. Lehmann, V., Stengl, R., Luigart, A.: ‘On the morphology and the electrochemical formation mechanism of mesoporous silicon’, Mater. Sci. Eng., 2000, B69-70, pp. 11–22 (doi: 10.1016/S0921-5107(99)00286-X).
25. 25)
  - 23. Dimitrios, N., Pagonis, A.G.N.: ‘Free-standing macroporous silicon membranes over a large cavity for filtering and lab-on-chip applications’, Microelectron. Eng., 2006, 83, pp. 1421–1425 (doi: 10.1016/j.mee.2006.01.065).
26. 26)
  - 26. Chuang, S.F., Collins, S., Smith, R.: ‘Porous silicon microstructure as studied by transmission electron microscopy’, Appl. Phys. Lett., 1989, 55, (15), pp. 1540–1542 (doi: 10.1063/1.102239).
27. 27)
  - 1. Turner, D.R.: ‘Electropolishing silicon in hydrofluoric acid solutions’, J. Electrochem. Soc., 1958, 105, pp. 402–408 (doi: 10.1149/1.2428873).

Login

Not registered yet?

Share

Tools

Login to add to favourites

Key

Effect of current density on silicon surface in electrochemical etching

References

Related content