Fabrication of a single-electron transistor with mesoscopic tunnel junctions

We developed SETs made by aluminum electrodes and Al/AlOx/Al tunnel junctions, and tested their behavior at 0.3 K in the superconducting regime. The devices are fabricated using a double-angle evaporation through a suspended resist mask, defined by electron-beam lithography (shadow mask and tilted evaporation technique). By exploiting the shadow effect, we can reduce the junction dimensions and achieve a figure of 70 nm for the junction side. In this work we will show our experimental results both on the fabrication and on the performance of the superconducting single-electron transistors.