Silicon nanofilter with absolute pore size and high mechanical strength

Wen Hwa Chu, Mauro Ferrari

Research output: Chapter in Book/Report/Conference proceedingConference contribution

26 Scopus citations


Microfabricated silicon filters with a nominal pore size of 20 nm have been successfully fabricated and characterized. The filter consists of a filtration membrane on top of a silicon surface and a mechanical support on the silicon substrate. Two polysilicon layers together with a low temperature oxide layer are used to generate the filtration membrane on the front side of silicon wafers. The filtration function is accomplished by the flow channel generated from a sandwiched thin silicon dioxide layer. The thickness of the sandwiched oxide determines the particle size that can pass through the filter. Both distilled water and cell culture medium have been used to test the flow rate for this nanofilter. We have found that the flow rate of the nanofilter is highest at the beginning of the test, and then slowly decreases to its asymptotic values for both water and the cell culture medium. The observed flow rate is linearly proportional to the applied pressure in the ranges tested. The typical flow rate of distilled water for 20 nm filter with 1.19 cm 2 effective filtration area is about 0.07 ml/min for applied pressure of 8 PSI. The filter successfully sustained pressure of up to 20 PSI.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsLynne E. Parker
Number of pages12
StatePublished - Dec 1 1995
EventMicrorobotics and Micromechanical Systems - Philadelphia, PA, USA
Duration: Oct 25 1995Oct 25 1995


OtherMicrorobotics and Micromechanical Systems
CityPhiladelphia, PA, USA

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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