Self-aligned double-gate single-electron transistor derived from 0.12-μm-scale electron-beam lithography

A single-electron transistor (SET) with two gates was fabricated via the self-aligned evaporation of Al into a trench structure comprised of Si and $SiO2.$ The initial trench, which was comparable to 0.12 μm lines and defined by electron-beam lithography, was reduced to $0.05×0.02 μm$ by a slightly anisotropic etching characteristic. These processes allow for the production of SET devices using current silicon fabrication techniques. The simultaneous formation of two gates allows for one gate to be used to control the background charge of each device. The shift of Coulomb oscillation peaks was clearly shown by controlling the second gate bias. An inverter logic operation at a temperature of 5 K with a gain of 1.3 was obtained. These characteristics indicate that such SET logic devices, based on a combination of the good performance of the Al SET and the high level of control of the fabrication of Si technology, have considerable potential for future use.