Fabrication of atomic‐scale metallic microstructures by retarding‐field focused ion beams

Atomic‐scale metallic microstructures have been deposited on various semiconductor substrates. A retarding‐field method is used to form a low‐energy, focused beam of Au ions from a liquid metal alloy source. The ions were deposited with landing energies down to 20 eV to form ultrathin films. The microstructure of the ultrathin films was found to be metallic islands, the smallest of which are 1 nm or less. The microstructure on a GaAs substrate displayed a high degree of size and spacing regularity. The technique was used as a method to fabricate nanometer‐scale islands in a multiple‐junction Coulomb blockade device.