Performance of Sub-5 nm field-effect transistors based on ZrS2/NbTe2 heterojunction from quantum transport simulations

This study systematically investigates the transport properties of n-type field-effect transistors (FETs) with a monolayer (ML) ZrS₂ channel, using first-principles calculations and quantum transport simulations. A ZrS₂/NbTe₂ heterojunction with well-aligned work functions is employed as the electrodes, enabling n-type Ohmic contacts at both vertical and lateral interfaces of the FET. The introduction of an underlap (UL) structure effectively suppresses short-channel effects, reducing the off-state current ($I_{\text{off}}$) to 0.1 μA/μm. To further enhance gate controllability, environmentally stable high-κ dielectrics are employed. The total channel capacitance ($C_t$), delay time ($\tau$), and power-delay product ($PDP$) satisfy the International Technology Roadmap for Semiconductors (ITRS) 2028 high-performance (HP) standards. The device with a 2 nm UL and an HfO₂ dielectric achieves optimal performance, exhibiting an on-state current ($I_{\text{on}}$) of 2624 μA/μm, nearly three times higher than the ITRS 2028 HP standard for $I_{\text{on}}$. This study provides theoretical insights into the design of HP two-dimensional (2D) FETs.