Dielectric Interface Engineering for High-Performance Monolayer MoS2 Transistors via TaOxInterfacial Layer

Field-effect transistors (FETs) based on 2-D materials have great potential for future ultimate-scaled electronics. However, nonideal semiconductor–dielectric interfaces due to interfacial traps and oxide traps have constrained the potential of 2-D semiconductors. Here, we report a new dielectric interface engineering approach for monolayer (1L) MoS2 transistors employing a relatively high- TaOx interfacial layer (7) whose defect bands are located outside of the operation window of the MoS2 Fermi level. Such band alignment can minimize active interface trap states in top-gate (TG) dielectric stacks. The TaOx interfacial layer can also act as an efficient doping layer, with the highest ON-current I ₎₍ reaching 861 A/ m at V ₃ₒ = 1. 5 V and overdrive voltage V ₎ₕ = 3 V. The lowest contact resistance is down to 230 m. Dual-gate (DG) FETs can achieve subthreshold slope (SS) values down to 70 mV/dec in short-channel devices (L ₂₇ =55 –75 nm). Our reported SS, I ₎₍, and R₂ are among the best-reported values for MoS2 devices. For low-power applications, our devices exhibit a record-high I ₎₍ of 598 A/ m at V ₃ₒ =0. 65 V. The new dielectric engineering approach proposed in this study can pave the way for realizing high-performance logic devices based on 2-D materials.