Preventing the Capillary-Induced Collapse of Vertical Nanostructures

Tanmay Ghosh, Eva Corinna Fritz, Deepan Balakrishnan, Ziyu Zhang, Nandi Vrancken, Utkarsh Anand, Hong Zhang, N. Duane Loh, Xiumei Xu, Frank Holsteyns, Christian A. Nijhuis*, Utkur Mirsaidov*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

8 Citations (Scopus)
220 Downloads (Pure)


Robust processes to fabricate densely packed high-aspect-ratio (HAR) vertical semiconductor nanostructures are important for applications in microelectronics, energy storage and conversion. One of the main challenges in manufacturing these nanostructures is pattern collapse, which is the damage induced by capillary forces from numerous solution-based processes used during their fabrication. Here, using an array of vertical silicon (Si) nanopillars as test structures, we demonstrate that pattern collapse can be greatly reduced by a solution-phase deposition method to coat the nanopillars with self-assembled monolayers (SAMs). As the main cause for pattern collapse is strong adhesion between the nanopillars, we systematically evaluated SAMs with different surface energy components and identified H-bonding between the surfaces to have the largest contribution to the adhesion. The advantage of the solution-phase deposition method is that it can be implemented before any drying step, which causes patterns to collapse. Moreover, after drying, these SAMs can be easily removed using a gentle air-plasma treatment right before the next fabrication step, leaving a clean nanopillar surface behind. Therefore, our approach provides a facile and effective method to prevent the drying-induced pattern collapse in micro- and nanofabrication processes.

Original languageEnglish
Pages (from-to)5537-5544
Number of pages8
JournalACS Applied Materials and Interfaces
Issue number4
Publication statusPublished - 18 Jan 2022


  • capillary forces
  • high-aspect-ratio nanostructures
  • pattern collapse
  • self-assembled monolayers
  • silane
  • 2023 OA procedure


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