Impact of device scaling on the electrical properties of MoS2 field-effect transistors

Two-dimensional semiconducting materials are considered as ideal candidates for ultimate device scaling. However, a systematic study on the performance and variability impact of scaling the different device dimensions is still lacking. Here we investigate the scaling behavior across 1300 devices fabricated on large-area grown MoS2 material with channel length down to 30 nm, contact length down to 13 nm and capacitive effective oxide thickness (CET) down to 1.9 nm. These devices show best-in-class performance with transconductance of 185 mu S/mu m and a minimum subthreshold swing (SS) of 86 mV/dec. We find that scaling the top-contact length has no impact on the contact resistance and electrostatics of three monolayers MoS2 transistors, because edge injection is dominant. Further, we identify that SS degradation occurs at short channel length and can be mitigated by reducing the CET and lowering the Schottky barrier height. Finally, using a power performance area (PPA) analysis, we present a roadmap of material improvements to make 2D devices competitive with silicon gate-all-around devices.

Automated summary

Two-dimensional semiconducting materials, such as MoS2, show promising performance for ultimate device scaling, with excellent transconductance and subthreshold swing. The study reveals that scaling the top-contact length does not affect the contact resistance and electrostatics in three monolayers MoS2 transistors, due to dominant edge injection. Furthermore, short channel lengths lead to subthreshold swing degradation, which can be mitigated by reducing the capacitive effective oxide thickness and lowering the Schottky barrier height.