Fabrication of porous membrane filter from p-type silicon

✍ Scribed by Grigoras, K. ;Franssila, S. ;Sikanen, T. ;Kotiaho, T. ;Kostiainen, R.

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 194 KB
• Volume: 202
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200461203

✦ Synopsis

Abstract

Macropore formation and applications of low‐doped p‐type silicon have been studied. Traditional hydrofluoric acid/ethanol/water electrolyte and organic electrolytes containing dimethyl sulfoxide and hydrofluoric acid were used, and different anodization current densities were applied in order to optimize the pore formation and prevent cracking of the layer. Thin crystalline membranes were prepared by anisotropic wet etching from the backside, using a silicon nitride layer as a mask. A similar silicon nitride layer was used to define the area of the membrane to be porosified. Macroporous silicon membranes have been fabricated and tested as a filter for biomedical samples. Fluorescently labeled polystyrene beads, 1 µm in diameter, were succesfully used to demonstrate filter action. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)