A native oxide high-κ gate dielectric for two-dimensional electronics


Silicon-based transistors are approaching their physical limits and thus new high-mobility semiconductors are sought to replace silicon in the microelectronics industry. Both bulk materials (such as silicon-germanium and III–V semiconductors) and low-dimensional nanomaterials (such as one-dimensional carbon nanotubes and two-dimensional transition metal dichalcogenides) have been explored, but, unlike silicon, which uses silicon dioxide (SiO2) as its gate dielectric, these materials suffer from the absence of a high-quality native oxide as a dielectric counterpart. This can lead to compatibility problems in practical devices. Here, we show that an atomically thin gate dielectric of bismuth selenite (Bi2SeO5) can be conformally formed via layer-by-layer oxidization of an underlying high-mobility two-dimensional semiconductor, Bi2O2Se. Using this native oxide dielectric, high-performance Bi2O2Se field-effect transistors can be created, as well as inverter circuits that exhibit a large voltage gain (as high as 150). The high dielectric constant (~21) of Bi2SeO5 allows its equivalent oxide thickness to be reduced to 0.9 nm while maintaining a gate leakage lower than thermal SiO2. The Bi2SeO5 can also be selectively etched away by a wet chemical method that leaves the mobility of the underlying Bi2O2Se semiconductor almost unchanged.

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Fig. 1: Crystal and electronic structures.
Fig. 2: Controlled oxidation of Bi2O2Se layers and facile etching of Bi2SeO5.
Fig. 3: Electrical properties of Bi2SeO5.
Fig. 4: Top-gated Bi2O2Se/Bi2SeO5 FETs and inverter circuit.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.


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We thank G.F. Dong for her help and discussions in measuring dielectric properties. We acknowledge financial support from the National Natural Science Foundation of China (21733001, 21525310, 51672007 and 11974023) and the National Basic Research Program of China (2016YFA0200101). P.G. also acknowledges support from the Key Area R&D Program of Guangdong Province (2018B010109009) and the Key R&D Program of Guangdong Province (2018B030327001). J.Y. and K.L. were supported by the US Department of Energy (DOE), Office of Science, Basic Energy Sciences (award no. DE-SC0019025).

Author information




H.P. conceived the original idea for the project. T.T. carried out the synthesis and structural characterizations of the bulk and 2D crystals. The devices were fabricated and measured by T.L., with help from L.X., Z.W., H.W. and R.J. H.F. and B.Y. carried out the theoretical calculations. The scanning transmission electron microscopy measurements were performed by Y.S. under the direction of P.G. MIM was performed by J.Y. under the supervision of K.L. The manuscript was written by H.P., T.L., T.T. and J.W. with input from the other authors. All work was supervised by H.P. All authors contributed to the scientific planning and discussions.

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Correspondence to Hailin Peng.

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Li, T., Tu, T., Sun, Y. et al. A native oxide high-κ gate dielectric for two-dimensional electronics. Nat Electron 3, 473–478 (2020). https://doi.org/10.1038/s41928-020-0444-6

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