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Nanoscale silicon substrate patterns from self-assembly of cylinder forming poly (styrene)-block-poly(dimethylsiloxane) block copolymer on silane functionalized surfaces

Lookup NU author(s): Dr Scott Watson, Dr Andrew Pike, Dr Ben Horrocks, Dr David Fulton, Professor Andrew HoultonORCiD



Poly(styrene)-block-poly(dimethylsiloxane) (PS-b-PDMS) is an excellent block copolymer (BCP) system for self-assembly and inorganic template fabrication because of its high Flory-Huggins parameter (chi similar to 0.26) at room temperature in comparison to other BCPs, and high selective etch contrast between PS and PDMS block for nanopatterning. In this work, self-assembly in PS-b-PDMS BCP is achieved by combining hydroxyl-terminated poly (dimethylsiloxane) (PDMS-OH) brush surfaces with solvent vapor annealing. As an alternative to standard brush chemistry, we report a simple method based on the use of surfaces functionalized with silane-based self-assembled monolayers (SAMs). A solution-based approach to SAM formation was adopted in this investigation. The influence of the SAM-modified surfaces upon BCP films was compared with polymer brush-based surfaces. The cylinder forming PS-b-PDMS BCP and PDMS-OH polymer brush were synthesized by sequential living anionic polymerization. It was observed that silane SAMs provided the appropriate surface chemistry which, when combined with solvent annealing, led to microphase segregation in the BCP. It was also demonstrated that orientation of the PDMS cylinders may be controlled by judicious choice of the appropriate silane. The PDMS patterns were successfully used as an on-chip etch mask to transfer the BCP pattern to underlying silicon substrate with sub-25 nm silicon nanoscale features. This alternative SAM/BCP approach to nanopatternformation shows promising results, pertinent in the field of nanotechnology, and with much potential for application, such as in the fabrication of nanoimprint lithography stamps, nanofluidic devices or in narrow and multilevel interconnected lines.

Publication metadata

Author(s): Borah D, Cummins C, Rasappa S, Watson SMD, Pike AR, Horrocks BR, Fulton DA, Houlton A, Liontos G, Ntetsikas K, Avgeropoulos A, Morris MA

Publication type: Article

Publication status: Published

Journal: Nanotechnology

Year: 2017

Volume: 28

Issue: 4

Print publication date: 01/01/2017

Online publication date: 16/12/2016

Acceptance date: 01/11/2016

Date deposited: 08/02/2017

ISSN (print): 0957-4484

ISSN (electronic): 1361-6528

Publisher: IOP Publishing


DOI: 10.1088/1361-6528/28/4/044001


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Funder referenceFunder name
EU FP7 NMP project
09/IN.1/602Science Foundation Ireland
245565LAMAND project