A simple method for fabricating a Si-based single electron transistor

A simple method, based on overlapping the dosage distribution of discrete electron beam (e-beam) written nano-dots, was employed to fabricate nano-structures containing narrow constrictions. The e-beam writing process can be designed so that the electron dosage in the overlapping region is just above the threshold exposure dosage of the negative electron-beam resist. Since the overlapping region is narrower than the diameter of the quantum dot, after a reactive ion etching process, a quantum dot connected with side electrodes through narrow constrictions is formed, which is the basic structure of a single electron transistor (SET). The electronic characteristics of the fabricated Si-SET were analyzed, and found to be consistent with the expected behavior of electron transport through a gated quantum dot, according to the orthodox theory based on the Coulomb blockade of the quantum dot.