Symmetry of Gating in Double-Gate MoS2 FETs

In this article, we correlate various double-gate (DG) molybdenum disulfide (MoS
₂
) FET architectures with the contact resistance (R
_C
) and performance. We show that the MoS
₂
DGFETs can achieve near-ideal subthreshold slope and threshold voltage modulation. We demonstrate how these DGFETs enable extraction of the gate-dependent contact resistance using only two-point probe (2PP) measurements. We show that when MoS
₂
is either only above or below source/drain (S/D) metal contacts, only one of the two gates can modulate the contact resistance through electrostatic doping, even when both gates overlap the contacts with the associated overlap capacitance. Finally, we fabricate and characterize a new MoS
₂
DGFET structure in which MoS
₂
is both above and below the S/D contacts, to enable both gates to modulate R
_C
and the channel resistance (R
_CHANNEL
). We show that both gates of the new DGFET can reduce R
_C
leading to higher drive current and more symmetrical gating for design flexibility. This new architecture will be useful in applications of DGFETs in signal processing including mixing and low-noise amplification.