SELF-ALIGNED IN-LINE TUNNEL-JUNCTIONS FOR SINGLE-CHARGE ELECTRONICS

The self-aligned in-line (SAIL) technique has been applied to the prep aration of ultrasmall low-capacitance metallic tunnel junctions. By us ing e-beam lithography the area of Al/AlOx/Al contacts has so far been reduced to less than 0.005 mu m(2). At low temperatures high-ohmic do uble junctions with a small metallic island between them show the Coul omb blockade effect. The current through such a device could be modula ted by a voltage applied to a gate electrode capacitively coupled to t he island (single-electron transistor). Both single-charge phenomena h ave been observed at temperatures up to 1K.