Controllable doping and wrap-around contacts to electrolessly etched silicon nanowire arrays

Jyothi S. Sadhu, Hongxiang Tian, Timothy Spila, Junhwan Kim, Bruno Azeredo, Placid Ferreira, Sanjiv Sinha

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Top-down electroless chemical etching enables non-lithographic patterning of wafer-scale nanostructured arrays, but the etching on highly doped wafers produces porous structures. The lack of defect-free nanostructures at desired doping and the difficulties in forming reliable electrical side-contacts to the nanostructure arrays limits their integration into high performance nanoelectronics. We developed a barrier layer diffusion technique to controllably dope wafer-scale silicon nanowire arrays (1017-10 20 cm-3) produced by chemically etching lightly doped silicon wafers. In order to achieve low resistance top-side electrical contacts to the arrays, we developed a two step tip-doping procedure to locally dope the tips (∼1020 cm-3) to metallic levels. The dopant concentration is characterized by depth profiling using secondary ion mass spectroscopy and four-point probe electrical measurements. Further, array scale electrical measurements show that the tip-doping lowers the specific contact resistivity (∼10-5 Ω cm2) since the metallic tips enable direct tunneling of electrons across the nickel silicide contacts to the nanowire arrays. This work provides a scalable and cost-effective doping approach to control charge injection and charge conduction in nanowire arrays, thus advancing their integration into various device applications.

Original languageEnglish (US)
Article number375701
Issue number37
StatePublished - Sep 19 2014
Externally publishedYes


  • electrical contacts
  • metal assisted chemical etching
  • silicon nanowire arrays

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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