The use of a Si-based resist system and Ti electrode for the fabrication of sub-10 nm metal-insulator-metal tunnel junctions

We have developed a process which is applicable for the fabrication of single electron devices by utilizing a SiO2/c-Si bilayer electron beam resist. The process parameters were optimized especially for the fabrication of metal-insulator-metal tunnel junctions of sub-10 nm sizes. A suspended mask suitable for double angle evaporation was successfully fabricated. Employing the highly corrosion resistance material Ti as an electrode metal and two-step removal process against excess Ti over inorganic resist, we fabricated a structure with sub-10 nm Ti/TiOx/Ti double tunnel junctions and an island, which exhibited tunneling property.