Miniature tunnel junction by electron-beam-induced deposition

Electron-beam- (EB-) induced deposition using a precursor molecule was applied to making very thin metallic wires and metal/insulator/metal tunnel junctions for single-electron transport devices. Single wires, typically 8 nm thick and 13 nm wide, were produced on a substrate, using the primarily EB with 3 nm diameter. It was shown that oxygen plasma treatment of the substrate just before EB-induced deposition was effective to avoid hydrocarbon deposits which resulted in high-resistance films. A post-annealing procedure in gas ambient improved also the resistance of the wires up to three orders of magnitudes. A tunnel junction where three dots structure was connected to the wires was produced. Its electrical characteristics were fitted to a Fowler-Nordheim plot with a gradient which gradually increased when increasing the pitch of the dot array.