3 nm Channel MoS2 Transistors by Electromigration of Metal Interconnection

Abstract

Further scaling down the feature size of transistors is central for the development of next-generation electronic devices. However, fabrication of transistors with channel lengths down to 5 nm has been challenging due to lithography limit and short channel effects (SCEs). Here, we demonstrate an MoS2-based device with the shortest 3 nm channel length among global back-gated transistors by feedback-controlled electromigration of metal interconnection. The Si/SiO2-back-gated model device shows on/off ratios of up to 2 × 105 and exhibits a field-effect mobility of up to 33.5 cm2 V–1 s–1, which is, to the best of our knowledge, the highest value in the as-yet-reported same-type transistors with a sub-10 nm channel length. This good immunity of the device to SCEs is also corroborated by the COMSOL Multiphysics simulation. After replacing the thicker physical gate SiO2 dielectric and Si electrode with the 2D hexagonal boron nitride (h-BN) and graphene monolayer, respectively, for better gate control, the field-effect mobility is pushed to 51.2 cm2 V–1 s–1 and displays excellent switching characteristics with near-ideal subthreshold swing of 67 mV dec–1 and drain-induced barrier lowering as low as 0.378 V V–1. This work can promote further transistor downscaling and extend Moore’s law.