  Two-dimensional (2D) semiconductors have attracted tremendous interests as
natural passivation and atomically thin channels that could facilitate
continued transistor scaling. However, air-stable 2D semiconductors with high
performance were quite elusive. Recently, extremely air-stable MoSi2N4
monolayer had been successfully fabricated [Hong et al., Science 369, 670
(2020)]. To further reveal its potential applications in the sub-5 nm MOSFETs,
there is an urgent need to develop integrated circuits. Here we report
first-principles quantum transport simulations on the performance limits of n-
and p-type sub-5 nm monolayer (ML) MoSi2N4 metal-oxide-semiconductor FETs
(MOSFETs). We find that the on-state current in the MoSi2N4 MOSFETs can be
effectively manipulated by the length of gate and underlap (UL), as well as the
doping concentration. Very strikingly, we also find that the n-type devices the
optimized on-state current can reach up to 1390 and 1025 uA/um for the high
performance (HP) and low power (LP) applications, respectively, both of which
satisfy the International Technology Roadmap for Semiconductors (ITRS)
requirements. Whereas, the optimized on-state current can meet the LP
application (348 uA/um) for the p-type devices. Finally, we find that the
MoSi2N4 MOSFETs have ultra-low subthreshold swing and power delay product,
which have potential to realize the high speed and low power consumption
devices. Our results show that MoSi2N4 is an ideal 2D channel material for
future competitive ultrascaled devices.
