Room-temperature fabrication of anodic tantalum pentoxide for low-voltage electrowetting on dielectric (EWOD)

Li, Yifan, Parkes, William, Haworth, Les, Ross, A., Stevenson, J. and Walton, Anthony (2008) Room-temperature fabrication of anodic tantalum pentoxide for low-voltage electrowetting on dielectric (EWOD). Journal of Microelectromechanical Systems, 17 (6). pp. 1481-1488. ISSN 1057-7157

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This paper presents a robust anodic Ta2O5 dielectric as an alternative insulator for fabricating low-voltage electrowetting on dielectric (EWOD) systems. Previously reported low-voltage EWOD technologies require high-temperature processes ( > 435degC), which unlike this room temperature technology, are not compatible with standard copper and aluminum integrated circuit interconnect technology as well as polymer-based substrates. The anodized Ta2O5 forms a uniform pinhole free layer with a surface roughness (R a) of 0.6 nm. This robust film enables an ultrathin amorphous FluoroPolymer layer to be employed to reduce the EWOD driving voltage to 13 V. Both sub-20-nm Teflon-AF and CYTOP layers have been successfully coated on top of Ta2O5 with good adhesion. Applying voltages of 6-15 V significantly modified the contact angles of droplets in air on these samples (121deg to 81deg on Teflon-AF at 13 V and 114deg to 95deg on CYTOP at 6 V). Successful 14-V EWOD manipulation involving droplets being dispensed from a reservoir, their movement, followed by merging them together has been demonstrated using devices using a Teflon-AF + Ta2O5 dielectric.

Item Type: Article
Uncontrolled Keywords: Amorphous FluoroPolymer (aFP), CMOS, electrowetting on dielectric (EWOD), microfluidics
Subjects: F200 Materials Science
F300 Physics
H600 Electronic and Electrical Engineering
Department: Faculties > Engineering and Environment > Mechanical and Construction Engineering
Depositing User: Yifan Li
Date Deposited: 26 Feb 2015 13:50
Last Modified: 26 Oct 2015 16:15

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