Two-Dimensional ZrS<sub>2</sub> and HfS<sub>2</sub> for Making Sub-10\nnm High-Performance P‑Type Transistors

Two-dimensional\n(2D) transition metal dichalcogenide (TMDC) semiconductors\nhave been recognized as reliable candidates for future sub-10 nm physical\ngate length field-effect transistors (FETs). However, the device performance\nof 2D P-type devices is far inferior to that of N-type devices, which\nseriously hinders the development of complementary metal-oxide-semiconductor\n(CMOS) integrated circuits. Herein, we presented that two new 2D TMDC\nchannel materials, ZrS<sub>2</sub> and HfS<sub>2</sub>, can realize\nhigh-performance P-type MOSFETs through first-principles quantum transport\nsimulations. Different from the 2D MoS<sub>2</sub> and WSe<sub>2</sub>, the continuous in-plane <i>p</i>-orbitals at the valence\nband edge of 2D ZrS<sub>2</sub> and HfS<sub>2</sub> lead to a small\nhole effective mass of 0.24 m<sub>0</sub>. As a result, 2D ZrS<sub>2</sub> and HfS<sub>2</sub> P-type MOSFETs with 10 nm gate length\npossess an on-state current (<i>I</i><sub>on</sub>) as high\nas 2000 μA/μm. Moreover, even when the gate length shrinks\nto 5 nm, the <i>I</i><sub>on</sub> can also reach ∼1500\nμA/μm with the energy delay product ranging from 3 ×\n10<sup>–30</sup> to 1 × 10<sup>–29</sup> Js/μm,\nwhich are better than many other 2D P-type MOSFETs like MoS<sub>2</sub> and WSe<sub>2</sub>. Our work demonstrates that 2D ZrS<sub>2</sub> and HfS<sub>2</sub> are competitive channel materials for constructing\nfuture sub-10 nm P-type high-performance FETs.