Silicon-micromachined direct-pore filters for ultrafiltration

Wen Hwa Chu, Tony Huen, Jay K. Tu, Mauro Ferrari

Research output: Contribution to journalConference articlepeer-review

27 Scopus citations


A new silicon filter with straight filtration channels has been fabricated and characterized. The semi-permeable membrane of the filter is made of a sandwiched p+ polysilicon/oxide/p+ silicon structure. The sacrificial oxide between the two silicon layers determines the pore size of the filter. This filter can be mass produced and has very precise control over filtration channels (variation less than 25%). Two log reduction of 100 nm fluorescent particles has been achieved in our 50 nm filters. The tested filtration fluxes for filtered DI water, 0.1 M PBS and ethanol solution (75% wt) were 0.54 - 1.5, 0.10, 0.54 - 1.2 ml/cm2hr, respectively.

Original languageEnglish (US)
Pages (from-to)111-122
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 1997
EventMicro- and Nanofabricated Electro-Optical Mechanical Systems for Biomedical and Environmental Applications - San Jose, CA, United States
Duration: Feb 10 1997Feb 10 1997


  • Filtration
  • Immuno-isolation
  • Microelectro-mechanical-system
  • Micromachining
  • Semi-permeable membrane
  • Silicon filter
  • Ultrafiltration

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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