MINIATURE TUNNEL JUNCTION BY ELECTRON-BEAM-INDUCED DEPOSITION

Electron-beam- (EB-) induced deposition using a WF6 precursor molecule was applied to making very thin metallic wires and metal/insulator/me tal tunnel junctions for single-electron transport devices. Single wir es, typically 8 nm thick and 13 nm wide, were produced on a SiO2 subst rate, using the primarily EB with 3 nm diameter. It was shown that oxy gen plasma treatment of the substrate just before EB-induced depositio n was effective to avoid hydrocarbon deposits which resulted in high-r esistance films. A post-annealing procedure in H-2 gas ambient improve d 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 increasin g the pitch of the dot array.