Co-integrated Subthermionic 2D/2D WSe2/SnSe2 Vertical Tunnel FET and WSe2 MOSFET on same flake: towards a 2D/2D vdW Dual-Transport Steep Slope FET

N Oliva,L Capua,A M Ionescu,M Cavalieri

doi:10.1109/iedm19573.2019.8993643

Abstract

In this work we report the fabrication, co-integration and resulting performance of 2D/2D van der Waals (vdW) Vertical p-type Tunnel FETs and p-MOSFETs in a WSe 2 /SnSe 2 material system. We demonstrate the best ever reported combined performance in terms of subthermionic subthreshold swing (point swing less than 35 mV/dec and average swing smaller than 50 mV/dec over 1.5 decade at V DS from 300 mV to 700mV), I OFF <; 0.1 pA/um 2 , I ON ~10 nA/um 2 and I ON /I OFF > 10 5 at V DS = 500 mV, for a 2D/2D vertical Tunnel FET. Moreover, for the first time, the fabricated Tunnel FET shows clear regions of higher performance, in same 2D material system, than the 2D MOSFET below 500 mV. NDR at room temperature in the output characteristic, with I peak /I valley >10, demonstrates the dominant BTBT conduction. The low hysteresis of the devices show high quality HfO 2 gating with defect-free vdW gaps between the flakes.Finally, for the first time, we co-integrate on a single WSe 2 flake, using 4-terminal design and a common gate, a pTunnel FET and a pMOSFET with different threshold voltages. These can operate in parallel as Dual-Transport Switch: this device shows subthermionic swing (~55mV/dec point swing) of the TFET and a thermionic high on-current (~100nA/um 2 at V DS = 500mV) summing-up MOSFET and Tunnel FET currents, outperforming the individual components.

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