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Metal–oxide–semiconductor field-effect transistor with a vacuum channel


High-speed electronic devices rely on short carrier transport times, which are usually achieved by decreasing the channel length and/or increasing the carrier velocity. Ideally, the carriers enter into a ballistic transport regime in which they are not scattered1. However, it is difficult to achieve ballistic transport in a solid-state medium because the high electric fields used to increase the carrier velocity also increase scattering2. Vacuum is an ideal medium for ballistic transport, but vacuum electronic devices commonly suffer from low emission currents and high operating voltages. Here, we report the fabrication of a low-voltage field-effect transistor with a vertical vacuum channel (channel length of 20 nm) etched into a metal–oxide–semiconductor substrate. We measure a transconductance of 20 nS µm–1, an on/off ratio of 500 and a turn-on gate voltage of 0.5 V under ambient conditions. Coulombic repulsion in the two-dimensional electron system3 at the interface between the oxide and the metal or the semiconductor reduces the energy barrier to electron emission, leading to a high emission current density (1 × 105 A cm–2) under a bias of only 1 V. The emission of two-dimensional electron systems into vacuum channels could enable a new class of low-power, high-speed transistors.

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Figure 1: Ballistic transport of electrons in nano-void channels in silicon MOS.
Figure 2: Energy band diagrams.
Figure 3: Measurement of electron capture efficiency at anode edges.
Figure 4: Nano-void channel FET.

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  1. Sze, S. M. (ed.) High-Speed Semiconductor Devices (Wiley, 1990).

  2. Leitenstorfer, A. et al. Femtosecond high-field transport in compound semiconductors. Phys. Rev. B 61, 16642–16652 (2000).

    Article  CAS  Google Scholar 

  3. Ando, T., Fowler, A. B. & Stern, F. Electronic properties of two-dimensional systems. Rev. Mod. Phys. 54, 437–672 (1982).

    Article  CAS  Google Scholar 

  4. Torium, A. et al. Experimental determination of finite inversion layer thickness in thin gate oxide MOSFETs. Surf. Sci. 170, 363–369 (1986).

    Article  Google Scholar 

  5. Mead, C. A. Anomalous capacitance of thin dielectric structures. Phys. Rev. Lett. 6, 545–546 (1961).

    Article  CAS  Google Scholar 

  6. Black, C. T. & Welser, J. J. Electric-field penetration into metals: consequences for high-dielectric-constant capacitors. IEEE Trans. Electron. Dev. 46, 776–780 (1999).

    Article  CAS  Google Scholar 

  7. Han, S. & Ihm, J. Role of the localized states in field emission of carbon nanotubes. Phys. Rev. B 61, 9986–9989 (2000).

    Article  CAS  Google Scholar 

  8. Zheng, X. et al. Quantum-mechanical investigation of field-emission mechanism of a micrometer-long single-walled carbon nanotube. Phys. Rev. Lett. 92, 106803 (2004).

    Article  Google Scholar 

  9. Mayer, A. Polarization of metallic carbon nanotubes from a model that includes both net charges and dipoles. Phys. Rev. B 71, 235333 (2005).

    Article  Google Scholar 

  10. Child, C. D. Discharge from hot CaO. Phys. Rev. 32, 492–511 (1911).

    CAS  Google Scholar 

  11. Langmuir, I. The effect of space charge and residual gases on thermionic currents in high vacuum. Phys. Rev. 2, 450–486 (1913).

    Article  Google Scholar 

  12. Grinberg, A. A., Luryi, S., Pinto, M. R. & Schryer, N. L. Space-charge-limited current in a film. IEEE Trans. Electron. Dev. 36, 1162–1170 (1989).

    Article  Google Scholar 

  13. Fowler, R. H. & Nordheim, L. Electron emission in intense electric fields. Proc. R. Soc. Lond. 119, 173–181 (1928).

    Article  CAS  Google Scholar 

  14. Spindt, C. A. A thin-film field-emission cathode. J. Appl. Phys. 39, 3504–3505 (1968).

    Article  CAS  Google Scholar 

  15. De Heer, W. A., Châtelain, A. & Ugarte, D. A carbon nanotube field-emission source. Science 270, 1179–1180 (1995).

    Article  CAS  Google Scholar 

  16. Teo, K. B. K. et al. Carbon nanotubes as cold cathodes. Nature 437, 968 (2005).

    Article  CAS  Google Scholar 

  17. Brodie, I. & Muray, J. J. The Physics of Micro/Nano-Fabrication (Plenum, 1992).

  18. Mil'shtein, S., Paludi, C. A. Jr, Chau, P. & Awrach, J. Perspectives and limitations of vacuum microtubes. J. Vac. Sci. Technol. A 11, 3126–3129 (1993).

    Article  CAS  Google Scholar 

  19. Lau, Y. Y., Liu, Y. & Parker, R. K. Electron emission: from the Fowler–Nordheim relation to the Child–Langmuir law. Phys. Plasmas 1, 2082–2085 (1994).

    Article  Google Scholar 

  20. Yang, G., Chen, K. K. & Marcus, R. B. Electron field emission through a very thin oxide layer. IEEE Trans. Electron. Dev. 38, 2373–2376 (1991).

    Article  CAS  Google Scholar 

  21. Yun, M., Turner, A., Roedel, R. J. & Kozicki, M. N. Novel lateral field emission device fabricated on silicon-on-insulator material. J. Vac. Sci. Technol. B 17, 1561–1566 (1999).

    Article  CAS  Google Scholar 

  22. Luryi, S. Quantum capacitance devices. Appl. Phys. Lett. 52, 501–503 (1988).

    Article  Google Scholar 

  23. Eisenstein, J. P., Pfeiffer, L. N. & West, K. W. Negative compressibility of interacting two-dimensional electron and quasiparticle gases. Phys. Rev. Lett. 68, 674–677 (1992).

    Article  CAS  Google Scholar 

  24. Huang, J. et al. Interaction effects in the transport of two-dimensional holes in GaAs. Preprint at (2006).

  25. Ho, L. H. et al. Ground-plane screening of Coulomb interactions in two-dimensional systems: how effectively can one two-dimensional system screen interactions in another. Phys. Rev. B 80, 155412 (2009).

    Article  Google Scholar 

  26. Li, L. et al. Very large capacitance enhancement in a two-dimensional electron system. Science 332, 825–828 (2011).

    Article  CAS  Google Scholar 

  27. Toriumi, A., Iwase, M. & Yoshimi, M. On the performance limit for Si MOSFETs: experimental study. IEEE Trans. Electron. Dev. 35, 999–1003 (1988).

    Article  CAS  Google Scholar 

  28. Pinto, M. R., Sangiorgi, E. & Bude, J. Silicon MOS transconductance scaling into the overshoot regime. IEEE Electron. Dev. Lett. 14, 375–378 (1993).

    Article  CAS  Google Scholar 

  29. Novoselov, K. S. et al. Electric field effect in atomically thin carbon films. Science 306, 666–669 (2004).

    Article  CAS  Google Scholar 

  30. Wu, Y. Q. et al. Record high RF performance for epitaxial graphene transistors. IEDM Tech. Dig. 528–530 (2011).

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This work was supported by the National Science Foundation (grant no. ECCS-0925532).

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Authors and Affiliations



S.S. carried out device processing and characterization. Y.S.J. performed FIB etching for nano-void channel fabrication. H.K.K. designed the study, provided theoretical guidance, and supervised the entire project. H.K.K. wrote the manuscript with comments from S.S. and Y.S.J.

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Correspondence to Hong Koo Kim.

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The authors declare no competing financial interests.

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Srisonphan, S., Jung, Y. & Kim, H. Metal–oxide–semiconductor field-effect transistor with a vacuum channel. Nature Nanotech 7, 504–508 (2012).

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