Shadow Nanosphere LithographyIntroductionNanosphere Lithography (NSL)Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9ShadowNanosphereLithographyPeter J. ShinDepartment of BioengineeringUC BerkeleyThe BioPOETSIntroduction•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., 2004UC BerkeleyThe BioPOETSNanosphere Lithography (NSL)Metal (Au, Ag) DepositionArray of Polystyrene Beads as MaskSi Substrate•Metal deposit with electron beam evaporation (EBE) system•Control over shape & size of patterns by varying bead radiusUC BerkeleyThe BioPOETSNanosphere Lithography (NSL)Top View Side View1. Bead Coating(self-assembled monolayers)2. Deposit Metal3. Bead Removal(toluene, tape)UC BerkeleyThe BioPOETSNanosphere Lithography (NSL)Targeted Patternscanning electron microscopy (SEM)image resulting from fabrication process(image from Van Duyne’s group)UC BerkeleyThe BioPOETSShadow Nanosphere Lithography* Modified EBE System–Sample–Metal source5. e-beam sourceΘ : angle between sample & metal sourceα : angle of sample rotationUC BerkeleyThe BioPOETSShadow Nanosphere LithographyMetal (Au, Ag) DepositionΘαVarying α resulting in nanowireSampleRotationVarying Θ resulting in complex morphologyUC BerkeleyThe BioPOETSShadow Nanosphere LithographyΘ = 0° & α = 0° leads to conventional NSL150nm Cr with Θ = 25°+ 15nm Ni with Θ = 0°Conventional NSL Shadow NSLvsUC BerkeleyThe BioPOETSThank
View Full Document
Unlocking...