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Scalable integration of hybrid high-κ dielectric materials on two-dimensional semiconductors

Nature Materials volume 22, pages 1078–1084 (2023)Cite this article

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Abstract

Two-dimensional (2D) semiconductors are promising channel materials for next-generation field-effect transistors (FETs). However, it remains challenging to integrate ultrathin and uniform high-κ dielectrics on 2D semiconductors to fabricate FETs with large gate capacitance. We report a versatile two-step approach to integrating high-quality dielectric film with sub-1 nm equivalent oxide thickness (EOT) on 2D semiconductors. Inorganic molecular crystal Sb2O3 is homogeneously deposited on 2D semiconductors as a buffer layer, which forms a high-quality oxide-to-semiconductor interface and offers a highly hydrophilic surface, enabling the integration of high-κ dielectrics via atomic layer deposition. Using this approach, we can fabricate monolayer molybdenum disulfide-based FETs with the thinnest EOT (0.67 nm). The transistors exhibit an on/off ratio of over 106 using an ultra-low operating voltage of 0.4 V, achieving unprecedently high gating efficiency. Our results may pave the way for the application of 2D materials in low-power ultrascaling electronics.

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Fig. 1: Integration process and structure characterizations of the ultrathin high-κ dielectric layer on 2D materials.
Fig. 2: The formation mechanisms of Sb2O3 and HfO2 layers on 2D materials.
Fig. 3: Low-power FETs and logic gates with our hybrid dielectric layer as gate dielectrics.
Fig. 4: 2D FETs with shorter channels and the benchmark of the 2D FETs with Sb2O3/HfO2 hybrid layer as gate dielectrics.

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The data that support the findings of this study are included in the article and Supplementary Information, and are available from the corresponding author upon reasonable request.

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All computational data are presented in the paper.

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Acknowledgements

This work was supported by the National Nature Science Foundation of China (grant nos. 21825103 (T.Z.), U21A2069 (T.Z.) and 52202171 (K.L.)). We also acknowledge the Analytical and Testing Center of Huazhong University of Science and Technology for the XPS characterizations and analysis. We thank Y. Gao and L. Sun (Huazhong University of Science and Technology) for providing us with graphene and measuring the contact angle.

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  1. These authors contributed equally: Yongshan Xu, Teng Liu.

Authors and Affiliations

  1. State Key Laboratory of Materials Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, China

    Yongshan Xu, Teng Liu, Kailang Liu, Yinghe Zhao, Lixin Liu, Jun Yu, Xin Feng, Fuwei Zhuge, Huiqiao Li & Tianyou Zhai

  2. National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China

    Lei Liu & Xinran Wang

  3. Center for High Pressure Science, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, China

    Penghui Li & Anmin Nie

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  1. Yongshan Xu
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Contributions

K.L. and T.Z. conceived the ideas. Y.X. and K.L. designed and carried out most experiments under the supervision of T.Z. T.L. and Y.Z. carried out the work of the molecular dynamics simulation and first-principles calculations. P.L. and A.N. prepared the cross-sectional samples and performed the STEM characterizations. Lei Liu and X.W. prepared the large-scale monolayer MoS2. Lixin Liu, F.Z., X.F., J.Y. and H.L helped analyse the data. Y.X., K.L. and T.L. worked on the images with assistance from all the other authors. K.L. wrote the paper with input from all co-authors.

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Correspondence to Kailang Liu or Tianyou Zhai.

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Nature Materials thanks Xuan Gao and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Information

Supplementary Figs. 1–15 and Table 1.

Supplementary Video 1

The process of Sb2O3 molecules deposition on the surface of MoS2.

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Xu, Y., Liu, T., Liu, K. et al. Scalable integration of hybrid high-κ dielectric materials on two-dimensional semiconductors. Nat. Mater. 22, 1078–1084 (2023). https://doi.org/10.1038/s41563-023-01626-w

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