Fabrication of multilayer single-electron tunneling devices

A reliable process has been developed for the fabrication of multilevel single-electron tunneling (SET) devices. Using this process, we have fabricated SET devices with Au-SiO-Al and Al-AlOx-SiO-Al overlap capacitors. The SET transistors exhibit voltage gain and, despite the complex device structure, have a low charge noise (7×10−5e/√Hz). Moreover, the use of overlap capacitors in SET devices results in a reduction of cross capacitances down to 8%.