Simulation study of inversion, accumulation, and junctionless mode monolayer MoS2/Ge heterojunction nanosheet at 1.5 nm node

Abstract

This paper evaluates the performance of monolayer MoS₂/Ge heterojunction n-channel nanosheet (MGHJFET) in various operating modes, including inversion mode (IM), accumulation mode (AC), and junctionless mode (JL), at the 1.5 nm technology node. To investigate these MGHJFET characteristics, a hybrid simulation approach was employed, combining atomistic simulations using density functional theory (DFT) with technology-computer-aided design (TCAD) simulations. The electrical characteristics of three types of MGHJFETs with different channel doping levels were analyzed. Further assessment was conducted on the analog and digital performance of the MGHJFETs in IM, AC, and JL modes. The IM and AC MGHJFETs exhibit superior performance due to current modulation in the monolayer MoS₂. Specifically, the saturation current in IM and AC structures reaches up to $8.5\times 10^{-5}$  A, and the $I_{\mathrm{on}}$/$I_{\mathrm{off}}$ ratio achieves $10^6$. By utilizing the 2D monolayer MoS₂ material, the channel current of IM and AC MGHJFETs can be effectively modulated. Combined with the other advantages of 2D materials, this device is capable of scaling down to its smallest possible physical limits in the post-Moore era.