Memristor crossbar arrays with 6-nm half-pitch and 2-nm critical dimension

Abstract

The memristor1,2 is a promising building block for next-generation non-volatile memory3, artificial neural networks4,5,6,7 and bio-inspired computing systems8,9. Organizing small memristors into high-density crossbar arrays is critical to meet the ever-growing demands in high-capacity and low-energy consumption, but this is challenging because of difficulties in making highly ordered conductive nanoelectrodes. Carbon nanotubes, graphene nanoribbons and dopant nanowires have potential as electrodes for discrete nanodevices10,11,12,13,14, but unfortunately these are difficult to pack into ordered arrays. Transfer printing, on the other hand, is effective in generating dense electrode arrays15 but has yet to prove suitable for making fully random accessible crossbars. All the aforementioned electrodes have dramatically increased resistance at the nanoscale16,17,18, imposing a significant barrier to their adoption in operational circuits. Here we demonstrate memristor crossbar arrays with a 2-nm feature size and a single-layer density up to 4.5 terabits per square inch, comparable to the information density achieved using three-dimensional stacking in state-of-the-art 64-layer and multilevel 3D-NAND flash memory19. Memristors in the arrays switch with tens of nanoamperes electric current with nonlinear behaviour. The densely packed crossbar arrays of individually accessible, extremely small functional memristors provide a power-efficient solution for information storage and processing.

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Fig. 1: Nanofin enables low-resistance electrodes for memristor crossbars.
Fig. 2: Continuous Pt nanofin arrays fabricated on SiO2 with Ge wetting layers.
Fig. 3: The 2-nm memristor crossbar arrays.
Fig. 4: Negligible crosstalk in the 2-nm memristor crossbars.
Fig. 5: Demonstration of memory function for the 2-nm memristor crossbar array.

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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Acknowledgements

This work was supported by the US National Science Foundation (NSF) (ECCS-1253073). Part of the device fabrication work was conducted in the clean room of the Center for Hierarchical Manufacturing (CHM), an NSF Nanoscale Science and Engineering Center (NSEC) located at the University of Massachusetts Amherst. The TEM work used resources of the Center for Functional Nanomaterials, which is a US DOE Office of Science Facility, at Brookhaven National Laboratory under contract no. DE-SC0012704.

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Contributions

Q.X. conceived and designed the experiments. S.P. fabricated and measured the circuits. C.L., W.X. and H.X. conducted the focused ion beam and TEM characterization. S.P., Q.X., H.J. and J.J.Y. analysed the data. Q.X. and S.P. wrote the manuscript. All authors commented and approved the manuscript.

Corresponding author

Correspondence to Qiangfei Xia.

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Supplementary information

Supplementary Information

Supplementary Figures 1–22, Supplementary Notes 1–6, Supplementary References

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Pi, S., Li, C., Jiang, H. et al. Memristor crossbar arrays with 6-nm half-pitch and 2-nm critical dimension. Nature Nanotech 14, 35–39 (2019). https://doi.org/10.1038/s41565-018-0302-0

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