Composite aluminum silicon-single electron transistor with tunnel FET features

Silicon single electron transistors (SiSET) featuring aluminum island and degenerately-doped silicon source and drain leads with ultrathin SiO₂ as the tunnel barrier are presented. By replacing the doped silicon island with aluminum, we expect to produce an SET with uniform metal dot that exhibits periodic Coulomb blockade oscillations. By eliminating dopants from the island of the SiSET, we are able to study the effects of dopants in the silicon leads and access regions. The fabricated devices exhibit characteristics that are influenced by the electron and the dopant density in the leads. The conductance in a number of the devices can be significantly varied by the application of gate bias. At low temperature, these devices operate as SETs, but at room temperature, tunnel field effect transistor-like behaviors are observed.