Proximity electron lithography using permeable electron windows

This letter reports on an electron source consisting of thin electron-permeable windows and a carbon nanocoil emitter. Electron windows with diameters of 250 nm were fabricated using silicon micromachining technology. Carbon nanocoils that are selectively grown from silicon were used as emitters. Field-emitted electrons from the emitters are transmitted through the thin silicon electron windows with thicknesses in the range of 15-50 nm. The electron transmittance of the electron windows was evaluated and it was demonstrated that transmittances higher than 60% are achievable for the case of electron energies higher than 5 keV. Proximity electron lithography is demonstrated using 1.5×1.5 μ m2 electron windows with a thickness of 50 nm.