Two-Dimensional ZrS2 and HfS2 for Making Sub-10 nm High-Performance P-Type Transistors

Two-dimensional (2D) transition metal dichalcogenide (TMDC) semiconductors have been recognized as reliable candidates for future sub-10 nm physical gate length field-effect transistors (FETs). However, the device performance of 2D P-type devices is far inferior to that of N-type devices, which seriously hinders the development of complementary metal-oxide-semiconductor (CMOS) integrated circuits. Herein, we presented that two new 2D TMDC channel materials, ZrS₂ and HfS₂, can realize high-performance P-type MOSFETs through first-principles quantum transport simulations. Different from the 2D MoS₂ and WSe₂, the continuous in-plane p-orbitals at the valence band edge of 2D ZrS₂ and HfS₂ lead to a small hole effective mass of 0.24 m₀. As a result, 2D ZrS₂ and HfS₂ P-type MOSFETs with 10 nm gate length possess an on-state current (I_on) as high as 2000 μA/μm. Moreover, even when the gate length shrinks to 5 nm, the I_on can also reach ∼1500 μA/μm with the energy delay product ranging from 3 × 10^-30 to 1 × 10^-29 Js/μm, which are better than many other 2D P-type MOSFETs like MoS₂ and WSe₂. Our work demonstrates that 2D ZrS₂ and HfS₂ are competitive channel materials for constructing future sub-10 nm P-type high-performance FETs.