The fast growth of information technology has been sustained by continuous scaling down of the silicon-based metal–oxide field-effect transistor. However, such technology faces two major challenges to further scaling. First, the device electrostatics (the ability of the transistor’s gate electrode to control its channel potential) are degraded when the channel length is decreased, using conventional bulk materials such as silicon as the channel. Recently, two-dimensional semiconducting materials1,2,3,4,5,6,7 have emerged as promising candidates to replace silicon, as they can maintain excellent device electrostatics even at much reduced channel lengths. The second, more severe, challenge is that the supply voltage can no longer be scaled down by the same factor as the transistor dimensions because of the fundamental thermionic limitation of the steepness of turn-on characteristics, or subthreshold swing8,9. To enable scaling to continue without a power penalty, a different transistor mechanism is required to obtain subthermionic subthreshold swing, such as band-to-band tunnelling10,11,12,13,14,15,16. Here we demonstrate band-to-band tunnel field-effect transistors (tunnel-FETs), based on a two-dimensional semiconductor, that exhibit steep turn-on; subthreshold swing is a minimum of 3.9 millivolts per decade and an average of 31.1 millivolts per decade for four decades of drain current at room temperature. By using highly doped germanium as the source and atomically thin molybdenum disulfide as the channel, a vertical heterostructure is built with excellent electrostatics, a strain-free heterointerface, a low tunnelling barrier, and a large tunnelling area. Our atomically thin and layered semiconducting-channel tunnel-FET (ATLAS-TFET) is the only planar architecture tunnel-FET to achieve subthermionic subthreshold swing over four decades of drain current, as recommended in ref. 17, and is also the only tunnel-FET (in any architecture) to achieve this at a low power-supply voltage of 0.1 volts. Our device is at present the thinnest-channel subthermionic transistor, and has the potential to open up new avenues for ultra-dense and low-power integrated circuits, as well as for ultra-sensitive biosensors and gas sensors18,19,20,21.
Subscribe to Journal
Get full journal access for 1 year
only $3.83 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Novoselov, K. S. et al. Two-dimensional atomic crystals. Proc. Natl Acad. Sci. USA 102, 10451–10453 (2005)
Radisavljevic, B., Radenovic, A., Brivio, J., Giacometti, V. & Kis, A. Single-layer MoS2 transistors. Nature Nanotechnol. 6, 147–150 (2011)
Lee, C.-H. et al. Atomically thin p–n junctions with van der Waals heterointerfaces. Nature Nanotechnol. 9, 676–681 (2014)
Mak, K. F., Lee, C., Hone, J., Shan, J. & Heinz, T. F. Atomically thin MoS2: a new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010)
Wang, Q. H., Kalantar-Zadeh, K., Kis, A., Coleman, J. N. & Strano, M. S. Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. Nature Nanotechnol. 7, 699–712 (2012)
Fang, H. et al. High performance single layered WSe2 p-FETs with chemically doped contacts. Nano Lett. 12, 3788 (2012)
Liu, W. et al. Role of metal contacts in designing high-performance monolayer n-type WSe2 field effect transistors. Nano Lett. 13, 1983–1990 (2013)
Lundstrom, M. S. The MOSFET revisited: device physics and modeling at the nanoscale. In IEEE International SOI Conference Proceedings 17–19 (IEEE, 2006)
Sakurai, T. Perspectives of low-power VLSI’s. IEICE Trans. Electron. E87-C, 429–436 (2004)
Quinn, J. J. & Kawamoto, G. Subband spectroscopy by surface channel tunneling. Surf. Sci. 73, 190–196 (1978)
Baba, T. Proposal for surface tunnel transistors. Jpn. J. Appl. Phys. 31, L455–L457 (1992)
Bhuwalka, K. K. et al. Vertical tunnel field-effect transistor. IEEE Trans. Electron. Dev. 51, 279–282 (2004)
Zhang, Q., Zhao, W., Member, S. & Seabaugh, A. Low-subthreshold-swing tunnel transistors. IEEE Electron Device Lett. 27, 297–300 (2006)
Khatami, Y. & Banerjee, K. Steep subthreshold slope n- and p-type tunnel-FET devices for low-power and energy-efficient digital circuits. IEEE Trans. Electron. Dev. 56, 2752–2761 (2009)
Ionescu, A. M. & Riel, H. Tunnel field-effect transistors as energy-efficient electronic switches. Nature 479, 329–337 (2011)
Datta, S., Liu, H. & Narayanan, V. Tunnel FET technology: a reliability perspective. Microelectron. Reliab. 54, 861–874 (2014)
International Technology Roadmap for Semiconductors. http://www.itrs.net/ITRS%201999-2014%20Mtgs,%20Presentations%20&%20Links/2013ITRS/Summary2013.htm (2013)
Sarkar, D. & Banerjee, K. Proposal for tunnel-field-effect-transistor as ultra-sensitive and label-free biosensors. Appl. Phys. Lett. 100, 143108 (2012)
Rodgers, P. Biomolecular turn-ons. Nature Nanotechnol. 7, 275 (2012)
Sarkar, D., Gossner, H., Hansch, W. & Banerjee, K. Tunnel-field-effect-transistor based gas-sensor: introducing gas detection with a quantum-mechanical transducer. Appl. Phys. Lett. 102, 023110 (2013)
Sarkar, D. et al. MoS2 field-effect transistor for next-generation label-free biosensors. ACS Nano 8, 3992–4003 (2014)
Sze, S. M. & Ng, K. Physics of Semiconductor Devices 3rd edn (Wiley, 2008)
Sarkar, D., Krall, M. & Banerjee, K. Electron-hole duality during band-to-band tunneling process in graphene-nanoribbon tunnel-field-effect-transistors. Appl. Phys. Lett. 97, 263109 (2010)
Das, S., Prakash, A., Salazar, R. & Appenzeller, J. Toward low-power electronics: tunneling phenomena in transition metal dichalcogenides. ACS Nano 8, 1681–1689 (2014)
Roy, T. et al. Dual-gated MoS2/WSe2 van der Waals tunnel diodes and transistors. ACS Nano 9, 2071–2079 (2015)
Britnell, L. et al. Field-effect tunneling transistor based on vertical graphene heterostructures. Science 335, 947–950 (2012)
Georgiou, T. et al. Vertical field-effect transistor based on graphene-WS2 heterostructures for flexible and transparent electronics. Nature Nanotechnol. 8, 100–103 (2013)
Tomioka, K., Yoshimura, M. & Fukui, T. Steep-slope tunnel field-effect transistors using III–V nanowire/Si heterojunction. In IEEE Symposium on VLSI Technology 47–48 (IEEE, 2012)
Liu, W. et al. High-performance few-layer-MoS2 field-effect-transistor with record low contact-resistance. In IEEE International Electron Devices Meeting 499–502 (IEEE, 2013)
Lin, M.-W. et al. Mobility enhancement and highly efficient gating of monolayer MoS2 transistors with polymer electrolyte. J. Phys. D 45, 345102 (2012)
This work was supported by the Air Force Office of Scientific Research (grant FA9550-14-1-0268) and the US NSF (grant CCF-1162633). Y.G. was supported by the Army Research Office (MURI grant W911NF-11-1-0362). All process steps for device fabrication were carried out using the Nanostructure Cleanroom Facility at the California NanoSystems Institute and the Nanofabrication Facilities at UCSB—part of the National Nanotechnology Infrastructure Network. We made extensive use of the MRL Central Facilities at UCSB, which are supported by the MRSEC Program of the NSF (award no. DMR 1121053), a member of the NSF-funded Materials Research Facilities Network (http://www.mrfn.org).
The authors declare no competing financial interests.
About this article
Cite this article
Sarkar, D., Xie, X., Liu, W. et al. A subthermionic tunnel field-effect transistor with an atomically thin channel. Nature 526, 91–95 (2015). https://doi.org/10.1038/nature15387
Nature Nanotechnology (2020)
ACS Applied Materials & Interfaces (2020)
2D Materials (2020)
physica status solidi (a) (2020)
A multiple negative differential resistance heterojunction device and its circuit application to ternary static random access memory
Nanoscale Horizons (2020)