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Proceedings Paper

Silicon nanofilter with absolute pore size and high mechanical strength
Author(s): Wen Hwa Chu; Mauro Ferrari
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Paper Abstract

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 cm2 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.

Paper Details

Date Published: 18 December 1995
PDF: 12 pages
Proc. SPIE 2593, Microrobotics and Micromechanical Systems, (18 December 1995); doi: 10.1117/12.228643
Show Author Affiliations
Wen Hwa Chu, Univ. of California/Berkeley (United States)
Mauro Ferrari, Univ. of California/Berkeley (United States)

Published in SPIE Proceedings Vol. 2593:
Microrobotics and Micromechanical Systems
Lynne E. Parker, Editor(s)

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