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

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 86Kr26+ 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.

Reduced Electron Temperature in Silicon Multi-Quantum-Dot Single-Electron Tunneling Devices

“…To release this issue, therefore, the advanced sub-5 nm patterning techniques can be suggested as feasible ways to improve the device homogeneity. For example, recent advances in nanofabrication technology, such as scanning probe lithography [40], heavy ion lithography [41], extreme ultraviolet lithography [42,43], block copolymer self-assembly [44], may allow the precise undulation of the Si nanowire because these methods enable us to control both the fine size and the exact site of the sub-5 nm patterns.…”

Scalable Fabrication of Metallic Nanogaps at the Sub‐10 nm Level

“…In this way, Kollmann et al fabricated bowtieshaped gold patterns with nanogap separations as low as 6 nm at the center, see Figure 7e. [75] As an alternative to Ga and He milling, it is also possible to use high energy (MeV) beams of protons, neon and krypton to enable higher resolution patterning, [62,77,78] although we are not aware of them being used to pattern sub-10 nm MNGs.…”

“…Consequently, the spot size remains small for considerable distances above and below the focal plane, which allows for high‐resolution patterning even on tilted surfaces. [ 62 , 63 ]…”

“…As an alternative to Ga and He milling, it is also possible to use high energy (MeV) beams of protons, neon and krypton to enable higher resolution patterning, [ 62 , 77 , 78 ] although we are not aware of them being used to pattern sub‐10 nm MNGs.…”

“…Consequently, the spot size remains small for considerable distances above and below the focal plane, which allows for high-resolution patterning even on tilted surfaces. [62,63] The most widely used charged-particle-based method is electron beam lithography (see Figure 6a), in which an electronsensitive resist is exposed with a beam of low-to-medium energy electrons (<100 keV) generated by a heated filament (normally tungsten or lanthanum boride) or a field emission gun (normally tungsten). [64] For a fairly typical 30 keV electron source, the wavelength is around 7 pm-three orders of magnitude lower than the typical photon wavelength used in EUV lithography.…”