Sub-5 nm Lithography with Single GeV Heavy Ions Using Inorganic Resist.

Liu, Qing; Zhao, Jing; Guo, Jinlong; Wu, Ruqun; Liu, Wenjing; Chen, Yiqin; Du, Guanghua; Duan, Huigao · Nano Lett · 2021

basic_science · Level V

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Abstract

In this work, we demonstrate a process having the capability to realize single-digit nanometer lithography using single heavy ions. By adopting 2.15 GeV <sup>86</sup>Kr<sup>26+</sup> ions as the exposure source and hydrogen silsesquioxane (HSQ) as a negative-tone inorganic resist, ultrahigh-aspect-ratio nanofilaments with sub-5 nm feature size, following the trajectory of single heavy ions, were reliably obtained. Control experiments and simulation analysis indicate that the high-resolution capabilities of both HSQ resist and the heavy ions contribute the sub-5 nm fabrication result. Our work on the one hand provides a robust evidence that single heavy ions have the potential for single-digit nanometer lithography and on the other hand proves the capability of inorganic resists for reliable sub-5 nm patterning. Along with the further development of heavy-ion technology, their ultimate patterning resolution is supposed to be more accessible for device prototyping and resist evaluation at the single-digit nanometer scale.