Download - Shadow Nanosphere Lithography Peter J. Shin Department of Bioengineering

ShadowNanosphe

reLithograp

hyPeter J. ShinDepartment of Bioengineering

UC BerkeleyThe BioPOETS

Introduction

• Interested in Batch Fabrication technique for making biosensors (i.e. SERS substrate)

• Wanted features include - low cost manufacturing - regular patterns in large area (6” Si wafer) - very high uniformity

• A. Kosiorek, et al., Shadow Nanosphere Lithography: Simulation and Experiment, Nano Lett., 2004


Nanosphere Lithography (NSL)

Metal (Au, Ag) Deposition

Array of Polystyrene Beads as Mask

Si Substrate

• Metal deposit with electron beam evaporation (EBE) system

• Control over shape & size of patterns by varying bead radius



Top View Side View

1. Bead Coating(self-assembled monolayers)

2. Deposit Metal

3. Bead Removal(toluene, tape)



Targeted Pattern

scanning electron microscopy (SEM)image resulting from fabrication process(image from Van Duyne’s group)


Shadow Nanosphere Lithography

* Modified EBE System– Sample– Metal source5. e-beam source

Θ : angle between sample & metal source

α : angle of sample rotation



Metal (Au, Ag) Deposition Θ

αVarying α resulting in nanowire

SampleRotation

Varying Θ resulting in complex morphology



Θ = 0° & α = 0° leads to conventional NSL

150nm Cr with Θ = 25°+

15nm Ni with Θ = 0°

Conventional NSL Shadow NSLvs


Thank you!

Questions?

Download - Shadow Nanosphere Lithography Peter J. Shin Department of Bioengineering

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