1. Top-down technique Toshitake Takahashi 03/09/2009 EE235

2. Demonstrate a new method to fabricate single fluidic- channel of uniform channel width (11-50nm) and over 1.5cm in length Imprint mold is created by unconventional nanofabrication (crystallographic anisotropic etching…)

3. Overview (a) Innovative mold fabrication that creates a nanoimprint mold (b) Use of the mold to imprint the nanochannel line in a functional material layer (c) Optical RIE that transferres the imprinted patterns into a substrate

4. Schematic of fabrication steps for making imprint mold Anisotropic wet etching with KOH Atomically smooth sidewall Conformal deposition of SiNx ensure uniform channel width Channel width is defined by SiNx film thickness

5. SEM images of each step

6. Top-down SEM images of 17nm, 1.5cm long channel Uniform over the entire channel Offer sub-10nm lithographic resolution for patterning sub-20nm channel line

7. Channel continuity tests (1)DI water containing fluorescent dye (2) DNA labeled with TOTO-1 fluorescent dye (1) Flowing colored water(2) Flowing DNA in solution

8. Electrical conductance measurement With a salt solution, electrical conductance : G m =66.1 nS Electrical conductivity is σ=G m L/wd=10.2 S/m Microchannel Nanochannel Electrical conductance : G m =0.40 pS channel cross-section: 314 nm 2 =(17.7 nm×17.7 nm)

9. Conclusion Demonstrate the fabrication of a single, narrow (as small as 11nm), long (over 1.5cm) and continuous fluidic channel This technique can be used for a variety of innovative bio/chemical sensors, particullary single-stranded DNA sequencing device