Electron Holographic Lithography
The technique is readily extendible to electron waves as well, as demonstrated by the practice of electron holography. Spacings of a few nanometers or even less than a nanometer have been reported using electron holograms. This is because the wavelength of an electron is always shorter than for a photon of the same energy. The wavelength of an electron is given by the de Broglie relation h/p, where h is the Planck constant and p is the electron momentum. For example, a 1 keV electron has a wavelength of slightly less than 0.04 nm. A 5 eV electron has a wavelength of 0.55 nm. This yields X-ray-like resolution without depositing significant energy. In order to ensure against charging, it must be ensured that electrons can penetrate sufficiently to reach the conducting substrate.
A fundamental concern for using low-energy electrons (<<100 eV) with this technique is their natural tendency to repel one another due to Coulomb forces as well as Fermi-Dirac statistics, though electron anti-bunching has been verified only in a single case.
Read more about this topic: Interference Lithography