(Invited) 2D/3D Tunnel-FET: Toward Green Transistors and Sensors

Tuesday, 30 May 2017: 11:20
Churchill B2 (Hilton New Orleans Riverside)
W. Cao, J. Kang, and K. Banerjee (University of California, Santa Barbara)
MOSFETs have been the workhorse of the worldwide semiconductor industry and the primary building blocks of most electronic products of everyday use since the 1970’s. However, continuous miniaturization of MOSFETs, well beyond 100 nanometers, to sustain the ever growing need for increased transistor densities has given rise to a daunting power dissipation challenge during the past decade due to increasing leakage power arising from a fundamental limitation of their turn-on characteristics. This talk will examine the genesis of this challenge, and provide an overview of our recently demonstrated atomically-thin 2D layered semiconducting channel tunnel-FET (Nature 2015) that overcomes this challenge and is a new class of transistors in which electrons move in an extremely thin interface layer between a conventional 3D semiconductor (Germanium, as the source) and a thin film of atomically layered barrier material (molybdenum disulphide or MoS2, as the channel). The materials allow the electrons that carry the signal current to be injected through quantum mechanical band-to-band tunneling.

At present, our 2D/3D heterostructure TFET is the thinnest-channel subthermionic transistor ever made and exhibits unprecedented low leakage currents, high ON/OFF ratio, 2X higher ON current (w.r.t other experimental TFETs at 0.1 V), very low average subthreshold swing (SS) over four decades of drain current, and lowers power dissipation by over 90% compared to the state-of-the-art MOSFETs. Rigorous analysis of the physics of band-tails in 2D semiconductors and their various heterostructures, accomplished in our group (IEDM 2016), support the experimentally demonstrated minimum SS values. Moreover, we have also shown that 2D-material (such as MoS2) based conventional FETs provide an excellent platform for biosensing (ACS Nano 2014). Hence, 2D-TFETs that combine the advantages of an atomically-thin channel and the unprecedented sensitivity of a tunnel-FET (APL 2012), owing to their steep turn-on characteristics, can be employed for building a revolutionary new class of ultra-low power bio/gas sensors (Physics Today, Sept 2016).