Nano-gap Electrodes Developed Using Focused Ion Beam Technology

  • Takashi NagaseEmail author
Reference work entry


Maskless fabrication methods for nanogap electrodes using sputter etching with a Ga focused ion beam (FIB) are presented. These methods are based on the in situ monitoring of the etching steps by measuring the current through patterned electrode films. The etching steps were terminated electrically at a predetermined current level. In the present experiment, a 30-keV Ga FIB with a beam size of ~12 nm was irradiated on double-layered films consisting of a 10–30-nm-thick Au top electrode layer and a 1–2-nm-thick Ti bottom adhesion layer to form nanowires and nanogaps. Electrode gaps that were much narrower than the beam size could be reproducibly fabricated using the presented method. The controllability of the fabrication steps was significantly improved by using triple-layered films consisting of a thin Ti top layer, Au electrode, and a bottom Ti adhesion layer. The minimum gap width achieved was ~3 nm, and the fabrication yield reached ~90 % for ~3–6-nm wide gaps. Most of the fabricated nanogap electrodes showed high insulating resistances, ranging from 1 GΩ to 1 TΩ. The applicability of the fabricated nanogap electrodes to electron transport studies of nanometer-sized objects was examined using electrical measurements of Au colloidal nanoparticles.


Current Trace Etching Step Molecular Electronic Device Single Electron Tunneling Mechanically Controllable Break Junction 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. Aviram A, Ratner MA (1974) Molecular rectifiers. Chem Phys Lett 29:277CrossRefGoogle Scholar
  2. Bezryadin A, Dekker C, Schmid G (1997) Electrostatic trapping of single conducting nanoparticles between nanoelectrodes. Appl Phys Lett 71:1273CrossRefGoogle Scholar
  3. DeMarco AJ, Melngailis J (1999) Lateral growth of focused ion beam deposited platinum for stencil mask repair. J Vacuum Sci Technol B17:3154CrossRefGoogle Scholar
  4. Durkan C, Schneider MA, Welland ME (1999) Analysis of failure mechanisms in electrically stressed Au nanowires. J Appl Phys 86:1280CrossRefGoogle Scholar
  5. Gamo K, Namba S (1990) Ion beam assisted etching and deposition. J Vacuum Sci Technol B8:1927Google Scholar
  6. Gamo K, Takakura N, Samoto N, Shimizu R, Namba S (1984) Ion beam assisted deposition of metal organic films using focused ion beams. Jpn J Appl Phys 23:L293CrossRefGoogle Scholar
  7. Hatzor A, Weiss PS (2001) Molecular rulers for scaling down nanostructures. Science 291:1019Google Scholar
  8. Klein DL, McEuen PL, Katari JEB, Roth R, Alivisatos AP (1996) An approach to electrical studies of single nanocrystals. Appl Phys Lett 68:2574CrossRefGoogle Scholar
  9. Lambert MF, Goffman MF, Bourgoin JP, Hesto P (2003) Fabrication and characterization of sub-3 nm gaps for single-cluster and single-molecule experiments. Nanotechnology 14:772CrossRefGoogle Scholar
  10. Li T, Hu W, Zhu D (2010) Nanogap electrodes. Adv Mater 22:286CrossRefGoogle Scholar
  11. Liu K, Avouris P, Bucchignano J, Martel R, Sun S, Michl J (2002) Simple fabrication scheme for sub-10 nm electrode gaps using electron-beam lithography. Appl Phys Lett 80:865CrossRefGoogle Scholar
  12. McCarty GS (2004) Molecular lithography for wafer-scale fabrication of molecular junctions. Nano Lett 4:1391CrossRefGoogle Scholar
  13. Morpurgo AF, Marcus CM, Robinson DB (1999) Controlled fabrication of metallic electrodes with atomic separation. Appl Phys Lett 74:2084CrossRefGoogle Scholar
  14. Muller CJ, Vleeming BJ, Reed MA, Lamba JJS, Hara R, Jones L II, Tour JM (1996) Atomic probes: a search for conduction through a single molecule. Nanotechnology 7:409CrossRefGoogle Scholar
  15. Nagase T, Kubota T, Mashiko S (2003) Fabrication of nano-gap electrodes for measuring electrical properties of organic molecules using a focused ion beam. Thin Solid Films 438–439:374CrossRefGoogle Scholar
  16. Nagase T, Gamo K, Kubota T, Mashiko S (2005) Maskless fabrication of nanoelectrode structures with nanogaps by using Ga focused ion beams. Microelectron Eng 78–79:253CrossRefGoogle Scholar
  17. Nagase T, Gamo K, Kubota T, Mashiko S (2006a) Direct fabrication of nano-gap electrodes by focused ion beam etching. Thin Solid Films 499:279CrossRefGoogle Scholar
  18. Nagase T, Gamo K, Ueda R, Kubota T, Mashiko S (2006b) Maskless fabrication of nanogap electrodes by using Ga-focused ion beam etching. J Microlithogr Microfabr Microsyst 5:011006Google Scholar
  19. Nakayama M, Wakaya F, Yanagisawa J, Gamo K (1998) Focused ion beam etching of resist/Ni multilayer films and applications to metal island structure formation. J Vacuum Sci Technol B16:2511CrossRefGoogle Scholar
  20. Neureuther AR, Liu CY, Ting CH (1979) Modeling ion milling. J Vacuum Sci Technol 16:1767CrossRefGoogle Scholar
  21. Park H, Lim AKL, Alivisatos AP, Park J, McEuen PL (1999) Fabrication of metallic electrodes with nanometer separation by electromigration. Appl Phys Lett 75:301CrossRefGoogle Scholar
  22. Park H, Park J, Lim AKL, Anderson EH, Alivisatos AP, McEuen PL (2000) Nanomechanical oscillations in a single-C60 transistor. Nature 407:57CrossRefGoogle Scholar
  23. Park J, Pasupathy AN, Goldsmith JI, Chang C, Yaish Y, Petta JR, Rinkoski M, Sethna JP, Abruna HD, McEuen PL, Ralph DC (2002) Coulomb blockade and the Kondo effect in single-atom transistors. Nature 417:722CrossRefGoogle Scholar
  24. Reed MA, Zhou C, Muller CJ, Burgin TP, Tour JM (1997) Conductance of a molecular junction. Science 278:252CrossRefGoogle Scholar
  25. Saifullah MSM, Ondarcuhu T, Koltsov DK, Joachim C, Welland ME (2002) A reliable scheme for fabricating sub-5 nm co-planar junctions for single-molecule electronics. Nanotechnology 13:659CrossRefGoogle Scholar
  26. Shigeto K, Kawamura M, Kasumov AY, Tsukagoshi K, Kono K, Aoyagi Y (2006) Reproducible formation of nanoscale-gap electrodes for single-molecule measurements by combination of FIB deposition and tunneling current detection. Microelectron Eng 83:1471CrossRefGoogle Scholar

Copyright information

© Springer-Verlag London 2015

Authors and Affiliations

  1. 1.Department of Physics and Electronics, Graduate School of EngineeringOsaka Prefecture UniversitySakaiJapan

Personalised recommendations